*u‘n-‘ms.\ GENNTNATTON AND GROWTHSTUDIES TN ' .. EUPATORIUM ODORATUM FROM THE NEW AND ow WORLD TNTNNES ~ * Thesis fNrTheDegreeNf Phng MTcNTGAN STATE NNTvENsTTYg ’ NEBENNNEN AYODEJ! EDWARDS 1923 ‘ ‘ LIBRARY Michigan Scam University This is to certify that the thesis entitled GERMINATION AND GROWTH STUDIES IN EUPATORIUM ODORATUM FROM THE NEW AND OLD WORLD TROPICS presented by ALEXANDER AYODEJI EDWARDS has been accepted towards fulfillment of the requirements for Ph.D. degree in Botany l‘ajor professor Datje g 71;, /¢‘7 3 0-7 639 ABSTRACT GERMINATION AND GROWTH STUDIES IN EUPATORIUM ODORATUM FROM THE NEW AND OLD WORLD TROPICS BY Alexander Ayodeji Edwards Selected characteristics of Eupatorium odoratum L. from seven localities in the New and Old World Tropics were investigated. Germinability, dormancy, leaf area ratio, root weight ratio, relative growth and net assimi- lation rates were examined under uniformly controlled environmental conditions. The effects of moisture, nitrogen and density on growth were observed among the plants from the seven localities. Significant differences were found among the plants from different localities in the rates and percentages of germination, and in time to reach maximum germination in response to soaking, moisture stress and light. The inhibitory effect of darkness on germination was reversible in seeds from six areas. Generally, germination occurred readily in the Species under the experimental conditions in this investigation. Variations and differences between plants in total dry weight, total nitrogen, root/shoot ratio, root weight Alexander Ayodeji Edwards ratio, and leaf area ratio were found to be significant at all samplings and treatments. The plants also differed in relative growth rate and net assimilation rate. Plants from the Paleotropics were found to have significantly lower leaf area ratio and higher root weight ratio and net assimilation rate than those from the Neotropics. Differences and variations in the characteristic germination behavior and growth functions among the plants observed in this investigation suggest that these charac- teristic features may be adaptive in this species. Signif- icant correlation of germination and some growth functions with mean annual precipitation of locality of origin as well as differences in reSponse to moisture stress suggest that plants from the seven localities may be climatic ecotypes. This study suggests that the ecological success of Eupatorium odoratum as an introduction to the Old World Tropics is in part due to its characteristic ability to germinate readily under various conditions of the environ- ment; also, due to the characteristic efficiency of the root system, or, of the photosynthetic apparatus. It is also possible that its success is due to the plastic nature of the Species, or its competitive ability in the absence of predators. GERMINATION AND GROWTH STUDIES IN EUPATORIUM ODORATUM FROM THE NEW AND OLD WORLD TROPICS BY Alexander Ayodeji Edwards A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Botany and Plant Pathology 1973 (60¢ 1 C; ACKNOWLEDGMENT S The author wishes to express his profound gratitude and appreciation to Dr. Stephen N. Stephenson his major professor, for his guidance, constructive criticisms and interest throughout the period of this study. Also, many thanks to Dr. J. A. D. Zeevaart,IRu Jack C. Elliott, Dr. John H. Beaman, and Dr. James M. Tiedje members of his guidance committee, for their valuable suggestions and expertise in the preparation of this manuscript. The author further extends his acknowledgment and gratitude to Dr. William B. Drew, for his assistance in obtaining seeds from Thailand, to Dr. Jack C. Elliot, for collecting seeds from Guatemala, to Dr. P. R. wychereley of the Rubber Research Institute of Malaya, and Dr. J. Bullock of the University of Malaya for providing seeds from Malaya, to Dr. R. E. Crutwell of the Commonwealth Institute of Biological Control, for collecting seeds from Trinidad, and to Mr. J. A. A. Akinniran for collecting seeds from Nigeria. Special thanks and sincere appreciation to Dr. William Tai for allowing the use of his photographic equipment and to Mr. Gilbert D. Starks for his assistance in photographing some of the materials in this manuscript, and to all his col- leagues who have contributed valuable suggestions in an ii ecological atmosphere throughout the period of this study. Finally, the author is greatly indebted to his wife and children whose constant support, patience and forbearance have made this study a reality. iii TABLE OF CONTENTS ACKNOWLEDGMENTS . . . . . . . LIST OF TABLES. . . . . . . . LIST OF FIGURES . . . . . . . INTRODUCTION . . . . . . . . MATERIALS AND METHODS . . . . . Characteristics and Distribution odoratum . . . . . . . Morphological Characteristics Geographical Distribution. . Ecological Characteristics . Dispersal . . . . . . . Economic Importance. . . . Seed Source . . . . . . Germination Studies . . . . Effects of Moisture. . . . Soaking. . . . . . . . Moisture Stress . . . . . Effect of Nitrate . . . . Effect of Light . . . . . Analyses of Results. . . . Growth Studies . . . . . . Effect of Moisture . . . . Effect of Nitrogen . . . . Effect of Density . . . . Calculation of Growth Functions. Analyses of Growth . . . . RESULTS AND DISCUSSION . . . . . Germination Studies . . . . General Observations . . . Effect of Soaking . . . . Effect of Moisture Tension . Effect of Nitrate . . . . Effect of Light . . . . . Discussion. . . . . . . Growth Studies . . . . . . General Observations on Growth Greenhouse Studies . . . . iv and Dev Eupatorium elopment. Page ii vi ix 12 12 12 13 15 16 20 21 23 23 24 24 25 26 26 27 28 30 31 31 34 35 35 35 44 46 52 52 60 60 63 Effect of Moisture Effect of Nitrogen Effect of Density GENERAL DISCUSSION SUMMARY . REFERENCES . APPENDIX. Page 78 86 97 113 117 118 129 ‘Table 1. Al. A2. A3. A4. LIST OF TABLES Localities of origin of seeds of Egpatorium odoratum with approximate latitude, longitude, mean annual rainfall, mean annual temperature, and code names . . . . . . . . . . . Relative growth rage gm/gm/wk, and net assimila- tion rate (cm /gm), in E. odoratum from seven localities over two sampling intervals . . . Simple correlation coefficient with climatic features of growth attirubutes of E. odoratum from seven localities. . . . . . . . . Relative growth rate (gm/gm/wk) in E. odoratum from seven localities at three moisture stress localities . . . . . . . . . . . . Net assimilation rate (gm/cmZ/wk) in E. odoratum from seven localities at three moisture stress localities . . . . . . . . . . . . Total dry weight, root weight ratio, leaf area ratio, relative growth rate, and net ' assimilation rate of seven localities of E. odoratum at two density levels. . . . . . Mean germination and standard error in E. odoratum from seven localities at four +—-—-r——t--I- inhibition levels . . . . . . . . . . Analysis of variance of mean germination in E. odoratum from seven localities at four soaking levels . . . . . . . . . . . Number of days to reach maximum germination and percentage germination in E.'odoratum from seven localities at four soaking levels. . . Percentage germination and number of days to reach maximum germination in parenthesis in E. odoratum from seven localities at varied moisture stress. . . . . . . . . . . vi Page 22 75 77 84 85 106 130 131 132 133 Table Page A5. Analysis of variance of percentage germination sin transformation in E. odoratum from six localities at various moisture tensions. . . 133 A6. Mean germination and standard error E. odoratum from seven localities at five molar concen- trations of KNO3 . . . . . . . . . . 134 A7. Mean germination and standard error in E. odoratum from seven localities under Tight treatment. . . . . . . . . . . . . 135 A8. Mean dry weight (g) at three sampling periods in E. odoratum from seven localities. . . . 136 A9. Analysis of variance of mean dry weight in E. odoratum from seven localities. . . . . . 136 A10. Mean root/shoot ratio (x10) at three sampling periods in E. odoratum from seven localities E. odoratum x 10 . . . . . . . . . . 137 All. Analysis of variance of mean root/shoot ratio in E. odoratum from seven localities. . . . 137 A12. Root weight ratio (RWR) and leaf area ratio (LAR) (cmZ/gm) of E. odoratum over three sampling periods from seven localities . . . 138 A13. Dry weight (g) of E. odoratum from seven locali- ties at three moisture levels . . . . . . 139 A14. Two-way analysis of variance of dry weight (gm) in E. odoratum from seven localities at three soil mOisture levels . . . . . . . . . 140 A15. Root/shoot ratio in E. odoratum from seven localities at three 5011 mOisture levels and three sampling periods x 10. . . . . . . 141 A16. Analysis of variance of root/shoot ratio in E. odoratum from seven localities at three sofl moisture levels. . . . . . . . . . . 142 A17. Root weight ratio in E. odoratum from seven localities at three—mOisture levels over two sampling intervals. . . . . . . . . . 143 vii Table Page A18. Analysis of variance of root weight ratio x 10 in E. odoratum from seven localities at three soil moisture levels at three sampling periods . . . . . . . . . . . . . 144 A19. Leaf area ratio (cmz/gm) in E. odoratum from seven localities at three moisture levels and two sampling intervals . . . . . . . . 145 A20. Analysis of variance of leaf area ratio in E. odoratum from seven localities at three soil mOisture levels at three sampling periods . . 146 A21. Mean dry weight (g) in E. odoratum from seven localities at two density levels over two sampling periods . . . . . . . . . . 147 A22. Mean root/shoot ratio E. odoratum from seven localities at two deHsiEy levels over two sampling periods . . . . . . . . . . 148 viii 10. 11. 12. 13. 14. LIST OF FIGURES Map showing present distribution of Eupatorium odoratum E. . . . . . . . Regeneration of E. odoratum in 3' of water in the flood plains of River Ogun in Nigeria . E. odoratum growing on roadside in Nigeria . Pappus and achene of E. odoratum showing bristle-like curved barbs . . . . . . Capitula and achenes of E. odoratum. . . . Total germination in seeds of E. odoratum from six localities at four soaking periods Mean germination and standard error in E. odoratum from seven localities at four soaking periods. . . . . . . . . . Rate of germination in E. odoratum from seven localities at four levels of soaking after 40 days . . . . . . . . . . Effect of soaking on germination rate in seven populations of E. odoratum . . . . Percentage germination in E. odoratum from six localities at varied moisture tension and their weighted means i 5; . . . . . Germination rate in six populations of E. odoratum at five moisture tension. . . . Effect of nitrate on germination of E. odoratum . . . . . . . . . . . . Effect of l x 10_1M KNO3 on germination of E. odoratum . . . . . . . . . . . Total germination in E. odoratum from seven localities at five molar concentrations Of KNO3 O O O O O O C O O O O 0 ix Page 14 17 17 18 19 36 38 40 43 45 47 48 49 51 Figure Page 15. Mean germination in E. ordoratum from seven localities at varied molar concentrations of KNO3 and their standard error . . . . 53 16. Total germination in E. odoratum from seven localities at three light treatments. . . 55 17. Total percent germination in E. odoratum from seven localities . . . . . . . . . 61 18. Mean dry weights of E. odoratum from seven localities on three harvest periods and their weighted means :S§’ . . . . . . 64 19. Means of dry weights :_S§ over three sampling periods in E..odoratum from seven localities . . . . . . . . . . . 65 20. Mean root/shoot ration of E. odoratum from seven localities calculated from mean D and Mean D and their weighted means : S; on three harvest periods . . . . . 67 21. Means of root/shoot ratio :S§ over three sampling periods in E. odoratum from seven localities . . . . . . . . . 68 22. Means of root weight ratio of E. odoratum localities over two sampling intervals . . 70 23. Mean leaf area (cm2) of E. odoratum from seven localities over three sampling periods . . . . . . . . . . . . 71 24. Means of leaf area (cm2) of E. odoratum from seven localities over three sampling periods . . . . . . . . . . . . 72 25. Mean leaf area ratio (cmz/gm) over two sampling intervals and their range in E. odoratum from seven localities. . . . . 74 26. Dry weight of E. odoratum from seven locali- ties at threE'mSISture levels and their weighted means :_S§ at three sampling periods . . . . . . . . . . . . 79 27. Root/shoot ratio of E. odoratum from seven localities at three moisture levels . . . 80 Figure ‘ Page 28. Comparison between LAR and RWR in E. odoratum from seven localities at three moisture levels over two sampling intervals . . . 82 29. Mean height (cm) per plant 0f.§' odoratum from seven localities treated with nitrogen six. . . . . . . . . . . 87 30. Mean number of leaves per plant of E. odoratum from seven localities treated with nitrogen :S;. c o o o o o o o o o 87 31. Effect of nitrogen on total dry weight (gm) and weighted means i S— in E. odoratum from seven localities at three sampling periods . . . . . . . . . . . . 89 32. Effect of nitrogen on root/shoot ratio in E. odoratum from seven localities at three sampling periods . . . . . . . . . 91 33. Total Kjeldahl nitrogen mg/gm dry weight and weighted means :S— in E. odoratum from seven localities Over three sampIing periOdS O O O O O O O O O O O O 92 34. Effect of nitrogen on leaf area (cmz) in E. odoratum at three sampling periods . . . 94 35. Mean leaf area ratio (cmZ/gm) in E. odoratum from seven localities over two sampling intervals. . . . . . . . . . . . 95 36. Average height per plant (cm) 1,3; of E. odoratum from seven localities at two density levels of three and six plants per pot . . . . . . . . . . . . 96 37. Average number of leaves per plant + S; in E. odoratum from seven localities at—two density levels of three and six plants per pot respectively . . . . . . . . . 99 38. Mean dry weight per plant per pot in E. odoratum from seven localities at two density levels . . . . . . . . . . 101 39. Mean root/shoot ratio per plant per pot in E. odoratum from seven localities at two denSity levels . . . . . . . . . . 101 xi Figure Page 40. Root weight ratio (gm gm 1) per plant of E. odoratgg from seven localities at two - density levels of three and six plants per pot . . . . . . . . . . . . 103 41. Leaf area ratio cmz/gm per plant per pot of E. odoratum from seven localities at two density levels of three and six plants per pot respectively . . . . . . . . . 104 42. Relationship between relative growth rate, net assimilation rate, and leaf area ratio in E. odoratum from seven localities (means and their range over two sampling intervals) . . . . . . . . . . . 108 43. Relationship between leaf area ratio and net assimilation rate in E. odoratum from seven localities at three mOisture levels . 109 xii 'f 4; < INTRODUCTION Plant species found in a diversity of habitats, particularly those species differentiated by regionally expressedantigeographically conditioned differences in climate, frequently consist of numerous ecotypes. Ecotypes are derived as a result of genotypical responses and adapta- tions to particular habitats. Variations occurring within species invading a new habitat may be morphological, physiological or both. The success of a species occurring in habitats other than its center of origin or geographic range may be due to the following: (1) the genotype, (2) ability to find an open niche, (3) lack of predation and (4) competition (Allard, 1965; Baker, 1965, 1967; Harper, 1965; Sakai, 1961, 1965; Stebbins, 1965). Many plant species that have become abundant or widespread in new or disturbed habitats are usually referred to as weeds. Disturbed habitats may be agricultural, waste places or roadsides. Ecologically, weedy species may be referred to as pioneers in a secondary successional sere. What makes a plant species weedy or non-weedy is a question that has not been fully resolved, however, species that are non-weedy in one habitat may become weedy if introduced into a new habitat. Weedy species have been shown, in general, to possess such characteristics as selfcompatibility, ability to flower quickly, high seed production, and neutral photoperiodism (Allard, 1965; Baker, 1965, 1967; Mulligan, 1965; Stebbins, 1965). Baker (1967) has shown that tolerance to environ- mental extremes such as light, shading, drought, and water- logging of the soil, have contributed to the success of Eupatorium microstemon as a weedy species. Harper and Chancellor (1960) have shown that the success of weedy BEEEE species was not only due to the number, size and reproductive capacity of individuals, but also tolerance to variation in water table conditions and soil type. Eupatorium odoratum L. is a recent introduction from tropical America to the flora of India, South East Asia, and Africa in the Old World Tropics (Adams, 1964; Bennett and Rao, 1968; Biswas, 1934; Moni and George, 1959). Introduction of this plant into areas of the Old World Tropics was accidental. It has become abundant and wide- spread within the last fifty years. The rapidity with which the species has spread has caused concern and stimulated investigation into possible eradication or biological control methods in India and Nigeria (Crutwell, 1968, 1969, 1971; Mohan Lal, 1960; Sheldrick, 1968). In Nigeria, observation of E. odoratum in a number of habitats has revealed differences in leaf area, petiole length, and internodes to be significant among eleven populations growing in different soil moisture conditions (Edwards, 1969, 1969a; Odukwe, 1965; Sheldrick, 1968). Observations over the two year period of 1967 and 1968 suggested that the spread of this species in Nigeria has reached its limit (Edwards, 1968). As suggested by the morphological variations found, the success of E. odoratum in this region of the Paleotropics appears to be related to some adaptations to the selective forces. In order to understand fully a plant species' successful establishment in a new habitat, either by natural or accidental introduction, one must examine such features of the life history as germination, seedling establishment, and growth in several populations. Results obtained from this type of approach may be useful in examining evolutionary trends in widespread species. Evolutionary trends may be morphological, physiological, reproductive, or combinations of all three. Variations or differences occurring in these attributes are more or less accentuated by the selective forces of the habitat. Germination and seedling establishment represent two of several critical stages in the life history of a plant species invading a new habitat. Modifications of the basic genotype program are expressed in a range of phenotypes (Bradshaw, 1965; Harper, 1965). Turesson (1922, 1925), noted that the point of primary importance in plant species is the genotypic constitution. He assigned the term 'ecotype' as an 'ecological unit' to cover the products arising as a result of the genotypical response of a plant species (ecospecies), to a particular habitat. The genetic program of the species which allows it to survive during the critical stages of development may include a range of possible develop- mental pathways. The pathway selected or the direction followed by the species will depend upon the environmental conditions to which the organism is exposed. Germination responses to factors of the enviroment such as moisture, light and temperature vary among and within populations of plant species. Seeds of many species have evolved ways to prevent desiccation of the embryo due to the moisture regime in the habitat. Harper and Benton (1966), also Harper and Sagar (1963) have shown that the failure of seeds of some plant species to germinate was the result of delayed or insufficient hydration of the seeds, a condition brought about by level of water table in the soil. Water uptake and available water (Lazenby, 1955; Toole g3_3l., 1956) have been shown to be two important aspects of moisture requirements of many plant species. Uptake of water by seeds of Atriplex canesceng (Springfield, 1966), Polyggnum (Timson, 1965), and Iva annua (Ungar and Hogan, 1970) has been shown to be related to soil moisture stress, or any combinations of physical factors of the habitat. In many weedy species, particularly those occurring in temperate climates, the presence of nitrates in the soil has been shown to increase germinability (Steinbauer and Grigsby, 1957, 1957a; Steinbauer gE_3E., 1955; Williams and Harper, 1965). The effect of nitrates in breaking dormancy may be dependent on other factors of the environ- ment such as light (Steinbauer and Grigsby, 1957), temperature and moisture (Steinbauer and Grigsby, 1957, 1957a; Williams and Harper, 1965). The importance of light and its effect on germina- tion of seeds has received much attention. When seeds are dispersed, they are either half or completely buried in the soil, or lie on the surface and covered with litter, or occupy cracks or crevices in the soil, or are completely exposed on the soil surface. They are thus exposed to light for some duration or not exposed at all. Germination of seeds in response to light revealed that variations occur on the inter- and intraspecific as well as inter- and intrapopulation levels (Caver and Harper, 1966; Cole, 1967; Shontz and Oosting, 1970; Toole gE_§E., 1956; Thurling, 1966). The effects of the factors of the environment on plant species cannotbe over-emphasized. Bradshaw (1959) showed that differences in vegetative heights, inflorescence heights, basal and aerial tillers, and the mode of spread of underground stems in populations of Agrostis tenuis Sibth. were due to the environment in which the populations grew. McWhorter (1971) in his study of populations of Sorghum halepense (L.) Pers. has shown that variations in growth habits were due to high fertility and adequate soil moisture. Robertson and Ward (1970) have concluded from their study of populations of Koeleria cristata (L.) Pers. that varia- tions in phenological and morphological attributes were due primarily to the moisture regime of the habitat. McKell et a1, (1962) studied populations of medusahead, Taeniatherum asperum (Simonkai) Nevski, an introduced annual grass to the United States, and concluded that the ecotypes differentiated mostly on phenological grounds. The study also showed rapid evolution in the species which has about an eighty-year history in the United States. The suggested reasons for the rapid evolution were, open niches in an almost closed community, high reproductive ability, and penetration of limited individuals of the species across a 'migration barrier' between the Old and the New World. The first two reasons given above may be applied to E. odoratum in the Old World Tropics. In a series of studies of Eupatorium rugosum Houtt., Kucera (1958, 1962) noted that differences in flowering response would suggest physiological variations in populations within the range of the species. He con- cluded that variations in the natural populations were the result of genotypic responses to varying climatic conditions within the broad range of the species. Although E. rugosum is not a weedy species, it is however widespread. It was also shown that differences in photoperiodic response were adaptations related to latitudinal distribution of E. rugosum (Cohen and Kucera, 1969). McMillan (1969, 1970) found that diverse photoperiodic responses in Xanthium strumarium L. were correlated with habitat and latitude. The study showed that a combination of critical night-length and maturity response formed the basis for reproductive adaptation in different climatic regimes of E. stramarium. Investigations of populations of several species of Amaranthus, Ulex europaeus L., and Cardamine indicated that differences in response to photoperiodism significantly correlated with date of flowering, habitat, and latitude (McWilliams gE_3E., 1966; Millener, 1962; Thurling, 1966). In order to understand fully how an invading species (introduced or otherwise) has become successful in a new habitat, it would perhaps be profitable to examine intrinsic physiological attributes such as accumulation of dry matter (biomass), root/shoot ratio, relative growth rate, leaf area ratio, and net assimilation rate. Also, the processes of respiration and photosynthesis must be included since they too contribute directly to growth functions. That differences in growth functions occur among populations have been clearly demonstrated with some field crops (Watson, 1947, 1952), and some annual and perennial species (Monk, 1966). In addition, Harper and Ogden (1970) have shown that allocation of energy varied during the life cycle of Senecio vulgaris L. They concluded that the reproductive effort was not affected by gross variations in individual plants. The idea of allocation of energy during the life cycle of the plant species, particularly at the seedling level, coupled with intrinsic growth functions, offer the prospect of utilizing them in interpreting the behavior of weedy species that have become successful in diverse habitats. Among the early investigators who used growth functions to explain the behavior of plant species was Watson (1947). He showed that there were variations in net assimilation rate, leaf area ratio and leaf area between species and varieties, and within years in field crops. The aim of Watson's investigation was to find a better method of assessing or predicting behavior of field crops under selection. Bjorkman and Holmgren (1961) showed that there were differences in respiratory rate among ecotypes of Solidago virgaurea. In an earlier work, they showed that differences in photosynthesis also occurred among populations of E. virgaurea. They concluded that maximum respiration and photosynthesis took place at different temperatures for the ecotypes studied. In recent years, growth functions have been utilized to assess the yield in the genus L01ium (Wilson and Cooper, 9 1969) in Dacgylis glomerata L. (Eagles, 1969), and in Festuca arundinacea Schreb. (Chatterjee, 1961). These workers were particularly interested in being able to assess the potential for improvement of field crops under selection. The application of growth functions to the study of weedy species was made by Hammerton (1965), and Hammerton and Stone (1966). They concluded that populations of Polygonum periscaria L., and E. lapgthifolium L. represented distinct ecotypes on the basis of correlation of growth functions with latitude of origin. It is evident that the success of an invading species hinges on: (1) the genotype; (2) modifications of the basic genotype patterns; (3) influence of the faCtors or features of the environment; (4) physical manifestations of the geno- type (phenotypes); (5) manipulations of internal processes (respiration, photosynthesis, and reproduction); and (6) growth functions and attributes which are manifestations of the internal processes. The idea has been suggested that examination and investigation of morphological variation within species is "like inspecting the 'tip of the iceberg', whereas the main complexity lies at the physiological level of the vital processes" (Briggs and Walters, 1969). It would appear therefore, that physiological approaches to the study of weedy species and, in particular, those that are widely distributed and have become abundant in areas of similar or varied environmental factors and habitats may yield useful 10 information and allow for greater understanding of the behavior of weedy species. There are many facets of the behavior of a plant species, particularly a successfully established migrant species, that must be examined in order to understand fully the mechanisms by which the species manipulates avail— able materials, energy and space. In order to obtain useful and meaningful information, a physiological approach to the study of plant species appears to be a realistic one. The importance of physiological attributes, particularly growth functions as relative growth rate, net assimilation, rate, root weight ratio, root/shoot ratio, and leaf area ratio, and their probable application in interpreting relationships among populations of plant species, has motivated the present study of Eupatorium odoratum. The statement can be made that upon introduction, a species may undergo physiological changes sometime during its life history in order to survive in a new habitat. There are many facets to the physiological changes a species may undergo. It is difficult to examine all of the facets because the rate, or time, or type of changes depend upon the genetic program of the species. It would be logical perhaps to examine such sensitive characteristics as growth rate, assimilation rate, root weight, or leaf area ratios during the early growth phase of the species, in order to determine whether changes in some or all of these are adaptive charact- eristics. Evaluation of these physiological characteristics 11 may also indicate the strategy associated with the genotype under varying conditions of the environment. The objective of this study therefore is to determine the strategy and adaptations of some physiological attributes in populations of E. odoratum that have contributed to its rapid spread within a relatively short period of time. MATERIALS AND METHODS Characteristics and Distribution of Eupatorium odoratum Morphological Characteristics Eupatorium odoratum is a member of the family Compositae (Asteraceae) in the tribe Eupatorieae. It is a straggling or somewhat scandent herb or shrub. The stems are pubescent and round, or sometimes angular at the nodes. The opposite and decussate, or sometimes whorled leaves are three-nerved at or near the base, sparsely to moderately pubescent beneath, velvety or hirsute and copiously yellow glandular above. The leaves, which are generally rhombic-ovate to lanceolate with long acuminate apices and cuneate bases, have margins that are serrate to dentate, or the upper leaves may be nearly entire. The flower heads or capitula are arranged in a terminal, trichotomous, convex corymb. The green—tipped involucral bracts are imbricate and enclose 12 - 35 purple, pale lavender, or whitish flowers. The styles are exerted, as long as the corolla, and of the same color. The pappus is whitish and approximately the same length as the dark brown to black, angular, barbed achene (Adams, 1964; Cheeseman, 1940; Hutchinson and Dalziel, 1963; Long and Lakela, 1971). 12 l3 Geographical Distribution \ Eupatorium odoratum is an example of a tropical species that has become recently established in new habitata far from its geographic range. This species is now widespread in the Old World Tropics and has been described as an "aggressive weed" (Bennett and Rao, 1968; Simmonds, 1965). Eupatorium odoratum is native to the West Indies and continental America from southern Florida to Paraguay in South America (Figure 1). It is abundant, but not widespread, in Trinidad and Tobago, Jamaica and Barbados. The continental range of the species extends from latitude 1808 in Bolivia and Paraguay in the south, through Costa Rica, Guatemala, Honduras and southern Mexico, and into southern United States in the north, where it occurs mainly in Dade and Monroe Counties in Florida (Cheeseman, 1928; Crutwell, 1969, 1970, 1971; Grashoff, 1969; Long and Lakela, 1971). The species was accidentally introduced into the Old World Tropics where it is now abundant and widespread. It was first recorded in India, Burma, Singapore, and Thailand by Biswas (1934), and subsequently in Ceylon and Malaya by Moni and George (1959), and Salgado (1963). From Tropical Asia, the species was introduced into Africa and was first described as a new species in Ghana and Nigeria by Adams (1964). Further observations of the spread of .m Edumuopo Edfluoummsm mo coflpsofluumflo ucomwum mcfl3onm msz|.H onsmflm 03. 002 on! .8 ow 00% 90.. oom— 00.3 n u u n . n n . . 1 i _ u . 1 n _ i . . . . . . 09 . u .. — . . . . . co _ . n u u n . u 0 . 20:02.0”: Pachom Eonm Espmuooo .m CH nouum Unmocoum poo coHumoHEHou Homozia.n ongofim .mooom mm #0 moumoHHmom unmfim wo coo: . 13 "‘0 $3.0: 2w Es: L3: mmfig .wwmzd _ E ,1- ..,_ . . 4 _ A . . 1 . T . . 1 . 1 . . .. . W 1 an MVP. % T w : OLLVNIWHB T . 1 “.1 1 . t l T .7. 2 . . t T , I ‘4 I 39 I. Illa .II IIIIIIJIII- - III I I It .liiqliI. ..I.. s I IIIIIDAIT I . a . . .1 . a L. a w m. -I . IL--- .I E I l l I 17 :«I- i z—4-‘ LIL; ' I i .1 l I I 1| 1| .lII ‘ , . . I. . HI MEAT . N s. MIA. coaumsaeumw m>HumH5EEoU :mwz 1--.,“ - l _ 3| Figure 7.--Continued. Mean Percentage of Germination 40 ~4L—o—4uxflmal -o—-O—4hours 2.4 « 0 o 4 3 MLYA l 1 1 g T T T * so 20 30 4b , 10 20 so 40 Days Days Figure 8.-—Rate of Germination in E. odoratum from Seven Localities at Four Levels of Soaking After 40 Days. 41 I E I -_.J._-.,‘. ,‘ ‘ _.a.i 30' I I *ourf 84-Homrs -w--- . .._. '”Co$tro l-Ia + 24vHours. I I T -_iw4 I I l a I ._,. I . ' >—‘-——— , II . - .t-.:._...-s+-4.IaeursM f—I—- l . . I I I ‘ I ,_ - .,__.- _--.._..__4L.__i;fl.. - I . ,- . ‘ I .' V v I I I -3 I, -I L--- 9.? axe; 6O 50 O 4 I?! P O 00 3 21.. GUAT I..-‘--" ‘ + a 1.-..-. 20 Days: LO, ommucmoumm cams Figure 8.--Continued. 42 case of seeds from Agege, Ifako, and Trinidad, more than 65% of germination was reached in 10 days at 4, 24, and 48 hours. Ninety percent was reached in 10 days after 1 hour in seeds from Guatemala. There were significant differences in the rate of germination among the seven seeds from localities at the l, 4, and 24 hours of soaking after 10 days. For example, at 1 hour, seeds from Agege, Ifako, and Guatemala had 62% of total germination, seeds from Trinidad and Thailand had 23%, and seeds from Sango Otta and Malaya had 15%. At 4 hours, seeds from Agege, Ifako, and Trinidad attained 65% followed by seeds from Sango Otta, Malaya, and Thailand with 30%, and Guatemala had 5%. At 24 hours, seeds from Agege and Ifako gave 60% of total germination, and the rest 40%. No significant differences were evident in the rate of germination in 10 days at 48 hours. In 20 days, however, significant differences occurred among seeds from Agege, Ifao, Thailand, and Guatemala with 66%, Malaya and Sango Otta with 17%, and Trinidad alone about 17% of the total germination (Figure 9). Germination in seeds from all localities was examined by a one-way analysis of variance using total germination for all levels of treatment. There were significant differences at P < 0.05. The pattern of differences was the same as using the results of the control alone. Seeds from the following localities did 43 D0 1. “O'O‘THLD 2 —-o-O-MLyA 2 54+NlM-a 2 +0-mso go *NIFA -. ”TRIO g ‘I. «Hr-nun? 3 t 3%. ///4}——~—0 I a a 0 < 3 Eco 5 4 g . < 1 mm 1 4/D/D’c CHECK 1m 0 100 § £80 6 6 é a g 5 69 ‘25 3 ' a. E at“ ‘ 3. z 3 1 z a. 1 4. Nouns ' 24mm GI 10 no 1so 10 2.0 30 D AYS DAYS Figure 9.--Effect of Soaking on Germination Rate in Seven Populations of E. odoratum. 44 not show any significant differences; Agege and Ifako, Malaya and Guatemala, Sango Otta and Malaya, using Student's "t". Differences among seeds from other local- ities were significant at P < 0.05. Effect of Moisture Tension Available moisture in the soil is a critical factor in seed germination and subsequent establishment of the seedling. Results showed that germination decreased with increasing moisture tension. Germination response among the seeds from the six localities was significant at different moisture tension levels. No germination occurred at 10 atm. In seeds from Trinidad and Guatemala, increased moisture tension appears to hve induced germination. For example, seeds from Trinidad gave germination of 68% at 5 atm., and 74% at 3 atm.; seeds from Guatemala gave 12% at 5 atm. Fifty percent germination of the control was observed at l, 3, and 5 atm. in seeds from Guatemala, Agege, Sango Otta, Malaya, and Trinidad (Figure 10). Maximum germination was attained in 15 days in seeds from Agege, Guatemala, and Trinidad, and 20 - 25 days in seeds from Thailand, Malaya, and Sango Otta. The range in which at least 30% germination was reached was 15 - 25 days; whereas in the soaking treatment, it took generally 20 - 30 days to reach maximum germination I I I ‘70 I I ‘ “ ‘ “ . I . I w I . I 8» I I I '3?66 1 I I a" ‘ W ' a I I I I -.-I. I I, __‘_l_... i _I EI I I I wI I I ' ' U 50. , ,:_._I__r - SI 3 ‘ 1 I I‘VI I I I 0| I I , I I I I L“ I , I ' I I. ‘ I I I . j I I I I I I I - ll- 5 30 I I ‘ , I ; I ‘ I, ... . . ._.r ‘ ‘ 4‘ I ' I I I - I ' I ’ 10?V,A,I_ I 5’_ ’ n ‘ ..I ,r,r . . u. ‘,_,_I.. ‘ I I I _ < I - l I I ‘ I I I I I I I . ' . I . t-G ’ ., '2 I: ‘ I; ' ‘I , ‘~ " ; ; . ,, I I I I I Moisture Stress in ATM. I I I I I Figure lO.--Percentage Germination in E. odoratum from Six Localities at Varied Moisture Tension and their Weighted Means i 5;. 46 (Figures 9 and ll). The rate of germination at all moisture tension levels was compared in Figure 11. Percentage germination of 43 and 47% observed in the seeds from Agege and Trinidad at moisture tension of l and 3 atm. were significantly different at P < 0.05 from the remaining' populations. At 5 and 8 atm., seeds from Trinidad with germination of 30 and 65% was significantly different from seeds from the remaining localities. No germination was observed in the seeds from Thailand and Guatemala at 8 atm. Effect of Nitrate It has been observed (Steinbauer and Grigsby, 1957, 1957a) that nitrates in the germination substrate increased germinability in seeds of some weed species and that the major activity was that of breaking dormancy. The effect of nitrate on breaking dormancy in E. odoratum was examined. Results indicated that nitrate did not break dormancy in E. odoratum. The presence of nitrate, however, affected the emergence of the primary leaves in seeds from five localities (Figure 12). Concentration of lO-lM KNO3 inhibited the growth of roots in all the seed sources studies. The general effect is shown in Figure 13. There were no significant differences in germina- tion in the control and treated seeds except at the 10.1 M KNO concentration level. Germination response in seeds 3 from each locality varied at the different levels of 47 .cofimcme wusumfloz Rik um. Esumuomuo .m «o mcoflumgmom me .5 93¢ cofiumcflfiuomonuéa musmwm ml 913 0» MW“: 3 I 9» W736 9 on 9 ace ‘ E 39w .0 a 2m m n .33.. J u o m a m .3, 3 ..II\ M 8 n. w. Ia gm 32.9.. a q...» 2. N m 3.." a H m w 8.... 5.6.. m Imam...“ - D 0 35¢ _ .IOAVI 052M 1.: :hh . Rt“. .~-.‘ ‘~ ‘-‘§‘§;‘.\ a, h 5 C ' U 1‘... I. “ ’I Figure 12.--Effect of nitrate on germination of E. odoratum A: Control; B: 1x10'5M; C: lxlO‘3M KNO3. Row 1. NISO; Row 2. NIFA; Row 3. TRND; Row 4. NIAG; Row 5. MLYA. 49 ion of t on germina M KNO3 -l odoratum. Figure l3.--Effect of l x 10 E. 50 nitrate concentrations (Figure 14). Total germination of 60% and above was observed in seeds from Thailand, Agege, and Trinidad; and less than 60% in the rest. This pattern of germination response to nitrate treatments was compar— able to that of soaking where seeds from the same localities had more than 60% germination. Also, seeds from Trinidad had the highest percent germination among seeds examined. Comparison of mean cumulative germination showed differences in response to nitrate treatment, for example, germination response in seeds from Thailand, Agege, and Trinidad were significantly different from seeds from Ifako, 5 4 Sango Otta, and Malaya at 10‘ M KNOB. At 10‘ ences in germination in seeds from Malaya and Sango Otta M, differ- were not significant; but differences among other seed sources were significant at P < 0.05. The differences in the seeds from Guatemala and seeds from other localities 3 M concentration of KNOB. Germination response in seeds from the Old World were highly significant at 10- Tropics varied from those from the New World TrOpics. Differences in germination among seeds from the seven localities could not be attributed to the effect of nitrate alone. Germination, for example, differed in seeds from the Far East (Thailand and Malaya), in seeds from Agege 51 .m I ozx no mcoflumuucmocou nmaoz m>flm um mmfluflamooq cm>mm Eoum Edumuoco .m CH coflumcflauwo Hmuoenu.va mudmflm C. 3 «504 Q J ¢n .JaE) IEIOJ. UOueUL Qumtflo $5 58ch floomv s 703; o... s IOU: m z .03 w s v.9 x. n 3.81 N Etcoo a 52 and Ifako, two of the three localities from Nigeria, and also in the two seed sources from the New World Tropics (Figure 15). Effect of Light The results of an experiment on the effect of light on germination in E. odoratum showed that light is an important factor in the germination of this species. Continuous darkness did not suppress germination in seeds from Trinidad and Agege which gave cumulative germination of 24 and 40, representing about 33% and 80% of those obtained for continuous light and 11 - 13 hour photoperiod respectively. The effect of continuous darkness inhibited germination in seeds from Guatemala. There were no signif- icant differences in germination among seeds from Malaya, Agege, Ifako, and Trinidad, under continuous light and 11 - 13 hour photoperiods. Total germination ranged from 32 = 63% for continuous light, and 31 to 70% for 11 — 13 hour photOperiods. Here again, the seeds from Trinidad had the highest percent germination (Figure 16). Discussion The germination behavior of E. odoratum in response to soaking, moisture stress, nitrate and light treatments varied among seeds from seven localities investigated. Differences and variations in percent germination, and w- m; '3“? “Kim ‘ .. 25 20 15 10 53 -{}{}—NIAG +‘_NISO “NIFA C O .H I U (U .5 5 E H OJ C) m B > .H 0 .LJ ‘5 H 2 -(»{}.THLD E -4.—.—MLYA 5 2 5 C. (U G) 2: 20 CD 15 EE%—’——flfl’.—— « 10 k\_ 5 d 7: .L. A 0.00 1x10_5 1x10‘2r 1x10’3 lxlO-Z 1x10-l Molar 1 Mean of Four Roplicates of 25 Seeds. Figure 15.--1Mean Germination in E. ordoratum from Seven Localities at Varied Molar Concentrations of KNO Standard Error. 3 and their a.‘ Th4-.- 54 \ | 41.11.1411! I r a . a n» .w . . Tl - ¢ 1 - . _ , .. . V _ . _ . . v _ fl _ . q A 1‘ Ilo ‘ . . 4 _v w . . _ u l m _ . . _ Yy III! .4 I‘ll.‘ loll‘lllll4.vll1 . . a . fl . . _ . r , _ . . . . . _. ,. . iv 1 « IL‘ b-51. H v‘l-v- ‘ili it . . _ , _ tllo lllll a . . _ b. ‘I “' l. I‘llL'l-‘ID‘ i " . . , . a k . ?. -~111| a I O I 1...? w i. I 1 ti? ' t ol 4‘! v I}: . A. I t o no ‘ C a m . a . _ o . r b..- ‘l Av l l . . q . ., _ _ .. _ . 1 a-Jh- l .oll.‘ it . IT ‘lllll. 1I‘Iu1.rllllt. ‘ y . :0 "ll 1 -GOHJMGHEHMD ®>MUMHSEESU Gmm2-. o S Figure 15.--Continued. 55 .mpcmfiummua pnmflq mouse um mmfiuflamooq cw>mm Eouw Edumuooo mw:._443 9 1:... d uoueugwdas) IE+0l rates of germination observed under the four environmental conditions may be due to adaptions withing the species. Excluding seeds from Thailand, soaking time signifw icantly affected germination in seeds from the remaining six localities investigated. For example, soaking for more than 1 hour did not significantly alter total germination in the seeds from Sango Otta. On the other hand, total germination after soaking for 1 hour and 48 hours was significantly different from the control in seeds from Guatemala. The response to soaking was highly correlated with precipitation of the localities from which the seeds originated (r = +0.79). High osmotic pressure appears to reduce total germination in seeds from the Old World Tropics; yet, in the seeds from the New World Tropics, and in particular, the seeds from Trinidad, there were significant increases in percent germination at high osmotic pressure; 15% and 20% more germination were observed than in the control. It was observed also that seeds from Malaya, Agege, and Sango Otta had about 50% germination of the control at 5 atm.; while the seeds from Agege had about 25% germina- tion of the control at 8 atm. Seeds from Thailand had 5% and 25% germination of the control at 3 and 5 atm. Differences in germination among the seeds were found to be due to the effects of soaking and moisture am... 55—117.. ‘13 stress; by comparing percent germination of the controls in the two experiments, no significant differences were observed. In the case of the seeds from Sango Otta, collection site is usually water-logged; also, the mean annual precipitation of 2286 mm in Malaya suggests that the seeds from that area may be found in areas of low moisture tensions. The fact that more than 50% germina- tion occurred at 3 and 5 atm. in seeds from Agege, Sango Otta, and Malaya may suggest the plastic nature of seeds from the Old World Tropics to variations in soil moisture conditions. Seeds from Agege perhaps showed a more plastic response than seeds from other areas of the Old World Tropics from the results obtained at the different moisture tensions. The differences in the rate of germination and percent germination at increased soaking time, as well as at increased osmotic pressure may be an adaptive feature of the seeds to moisture conditions at the different localities. At 1, 3 and 5 atm., seeds of E. odoratum from Trinidad had a significantly higher rate of germination and percent germination than seeds from other localities; at 3 and 5 atm., it had a significantly higher rate and percent germination than at other treatment levels includ- ing the control. Although seeds from Agege had a signifi— cantly higher rate and percent germination at l and 3 atm. 58 than seeds from other areas of the Old World Tropics, there was a decrease in both the rate and percent germina— tion at these two levels; and at 3 atm., the rate and the percent germinated were significantly lower than the con— trol. Seeds from Trinidad and Guatemala had significantly higher rate and percent germination at 24 and 48 hours soaking time than at either 1 and 4 hours or the control; :7 yet the rate was fairly uniform among the seeds from the Old World TrOpics. It thus appears from the data that some modifications in the germination behavior of r E. odoratum introduced into the Old World Tropics has occurred. These modifications may have been in the selec- tion for genotypes adapted to moist conditions. The presence of nitrate in the germination sub- strate did not appear to have any effect on germination in E. odoratum. Only the seeds from Agege showed signif- icant differences at increased nitrate concentrations. High concentrations of nitrate in the germination substrate is likely to inhibit germination and subsequent seedling establishment. The effect of nitrate, however, may be that of accelerating development of the seedling, particu— larly in the early emergence and expansion of the primary leaves. There is much literature on the effect of nitrate in breaking dormancy in seeds. There was no evidence from the results obtained that prolonged dormancy exists in the seeds of E. odoratum. The lack of prolonged dormancy perhaps is a characteristic of the seed that has contri- buted to the success of E. odoratum in the Old World Tropics; also, it may be a selective attribute that is basic in seeds from all the localities. Light affected germination in the seven localities of E. pdoratum. More than 40% germination was obtained when the seeds kept in continuous darkness were transferred to an 11 - 13 hour photoperiod. A dark period followed by light appeared to induce higher percentage germination in seeds from three areas. The data obtained may suggest that any buried viable seeds may germinate upon disturbance of the site, particularly those that are found on arable land. There is no evidence, however, to indicate whether longer periods of continuous darkness may eventually prevent germination. The results of these experiments may be used to explain the ecological implications associated with germi— nation behavior of introduced species in alien habitats. The data obtained may suggest also that variations and differences among the seeds from the seven localities may be due to adaptations in E. odoratum under the environ— mental factors investigated. The characteristic behavior of imbibition, or dormancy, or both appear to be similar in the seeds from the Old and New World Tropics. The number of seeds capable of germinating varied among the seed sources; seeds from Trinidad and Thailand had total 60 percent germination of 57% and 60%; seeds from Agege and Ifako had 50% and 52%; seeds from Malaya, Sango Otta, and Guatemala had 33% and 34%. By comparing percent germina- tion under different treatments with the total percent germination, it was found that increase or decrease in total germination was due to the effect of soaking time, moisture stress, and light. There seems to be sufficient evidence that the variability and differences in germination of seeds from seven localities investigated may be related to the features of the environment, particularly, precipitation, in the different localities. In order to understand fully the germination behavior of E. odoratum, further research is needed in the field and laboratory to verify the results obtained in this investigation; and, in addition, to determine light-moisture and temperature-moisture interactions on germination of E. odoratum as well as seeds of other weeds associated with it. It is also important to follow viability and germinability from the onset of seed production in order to determine what type of strategy has been utilized. Growth Studies General Observations on Growth and Develgpment Morphological differences and differences in the rate of growth were observed in the early stages of _—_-‘n-»2mfl .' “r. ? hm 61 .mmflpflamooq cm>mm anw W5umuoco .w cfl aoflumcHEMmu pcmoumm Hmuoell.na mnsmflm mmfluflamooq embw- ozme .mmHz- -omHz ocHz «we: . i .. . w P .. w - . - . i. 4.1- - .«T 14117.- . T d - J» . . r , . - . - . ”- ,- - T. - . , . » , 9.”. . .,-. . . . “fin- - i. .-...l 9.1;. Ill. TIT: . e - f -3 SI-o-Ir. -.. - - . - , H .. - . . . o - . . . - i - . F L 1 I! _ TI! . .. I AT ....... 1 I Tl"! ’ i l '01“ I! A iqullllLllll'! ll? Til?! ‘ Aillj » 113.1 _ A . A ”‘1' \T ' l O Iu till TIIII! rll.l JTII‘I .I T nl'llIl'l-II‘II ill! a ii I Ilr-T- it- Iii.» - 4 a ‘ ml» 1:" .I'TIIIII}! 0 II J ml‘ :1 fiIIAII'iI -§| vii-Iii ill. # |l?.||ul. I A D lill'll 'I I10 1". U i T I» ¢ I l 23- l YT-illluvl YT; ~n1.-II LIT»! . T 9.1 . 3i- T 1 l i I 1 i T i l i T i T J i l i i 'udtqeufmiéb queoieam T L Mf-——--O--A dp—o-o—o— T L l r L l' i -31 T . Ti H .T - 11 4+ w i IJFII _T---- -, , ..... 4.: .- - 1r 8 LITT+ITTTI.1TLr; ;.L w - .T- H N r Lo TH l OZ develOpment of E. odoratum. The plants from Guatemala were taller and weaker than plants from other areas. The leaves of plants from Florida were more or less glabrous and nearly entire. At twelve weeks, the internodes of plants from the Old World Tropics were short as compared to later formed internodes which were approximately three to four times as long. The first three pairs of leaves length, were seen to be generally smaller in surface area, and width than later developed ones. Occasionally, the plants from the Old World Tropics produced leaves that xvere orbiculate and nearly entire. The stems of plants iirom Florida and Guatemala were usually darker in color tflian in plants from other localities. Also, the young lxaaves are in general heavily pubescent except in young lfisaves of plants from Florida. The hypocotyl and lower epicotyl tend to become wcxody very early in growth. This characteristic was esnpecially noticed in plants growing in a water saturated ervvironment. Secondary roots emerged at this point under Ccnaditions just described. Differences in growth among Pliints growing in different soil moisture conditions were also noticed. Plants growing in a water saturated and dry Coruditions tend to have broader or smaller and densely hairy leaves than those plants growing at field capacity. 63 Greenhouse Studies The data presented here were from plants grown under uniform environmental conditions in the greenhouse to determine if there are variations in some physiological attributes within E. odoratum from Seven Localities. Dry weight.--There were significant differences among the plants in total plant dry weight. There was an increase in total dry weight in plants from Guatemala, -Agege, Sango Otta and Thailand at all sampling periods; “there was an increase in total dry weight in the plants :Erom Malaya and Trinidad between the first two samplings fk>1lowed by a decrease in total dry weight between the sensond and third samplings; the population from Florida srnowed a decrease in total dry weight at all sampling pexriods (Figure 18). There were significant differences iri plants from Guatemala and Malaya between the first two saunplings, and in plants from Guatemala, Thailand, Agege, arud Ifako between the second and third samplings. There WExre significant differences among the plants from seven arwaas in total dry weight over all sampling periods, except among plants from Malaya and Florida, and Agege anri Sango Otta (Figure 19). It appears that a definite trend in accumulation (If (Drganic matter (biomass) is seen among the plants from Seven localities. As early as the first sampling period, "Wag? fifltz‘hh‘. . x A E a HarVest Peri I _ i _ , I. wfiwu sm-ysmfi: ha l M ean 0f 4 Replicates. F' 8 \v A Three Harvest Periods and their Weighted Means is l gur" 113.--Mean Dry Weights of E. odoratum from Seven Localities on DR Y WEIGHT (GM) 15... r" -L. in 5.. . ri— ‘ ' "E “i...“ U . mo MINA N130 Eng TRND Fun m {OCALITI Figure l9.-—Means of Dry Weights + 8; Over Thrée Sampling Periods i1; E. odoratum from Seven Localities. 66 plants from Guatemala had the greatest biomass; this trend was maintained throughout the sampling periods. In a peri;: of four weeks from the first sampling, four distinct groups are seen: (1) plants from Guatemala, (2) the group of plants from Agege and Sango Otta, (3) those from Malaya and Florida, and (4) those from Trinidad (Figure 20). Root/shoot ratio.--Figure 20 shows the pattern of root/shoot ratio among plants from the seven areas investi~ :mzm L gated. Plants from Thailand and Sango Otta had a higher root/shoot ratio at the second sampling than at the first or the third sampling periods. Plants from Agege and Guatemala had lower root/shoot ratio at the second and third sampling periods than at the first. Plants from Malaya continued to increase in root/shoot ratio at second and third samplings. A lower root/shoot ratio was obtained for plants from Florida and Trinidad at the second sampling than at either the first or the third. All differences were significant among and between samplings at P < 0.05. An examination of root/shoot ratio over all sampling gperiods showed that plants from the Old World TrOpics had liigher root/shoot ratio than plants from the New World TErOpics. Plants from Thailand had the highest ratio of 6..81 : 0.14, and plants from Trinidad had the lowest ratio Of’ 3.99 : 0.26. All differences were significant at P ‘< 0.05. - ' ' ' """ 1.; TH ' I CHIMMTH—m' 5. "I" I- 51 . ‘ I , ~IIs——+:I—2.é m3}? I I I -, I I -- I- I .- I ' I '*_,¢_,g._-3.- NIAIGr‘*‘I’f" I “ - - ’1‘“ j ; I , I IIe—eI—«T. map I - I - I-- -I E «qt—Ari» GUATT~~—I——J-w¥ I ‘ ii «I.— ’ g Anal—6. TRND I I I I, 0.8I . ._--_. , ,..,.7_ Fla-_-_-I_,.--,- .-,, I __ i ”IQ—5%.: IID I - i - : I ' - : - ; - I - I a: . -_1.. -_- I- - I- I_.L - - I ; I z - I i - - I - 1.2... In , _ : j ',-,,.",I.'_7 ' I (14) - I , E - I I I - I0,-_§__ - ‘ , : \L - - I I 3 I - i \ ' ‘ 1.3: 0‘3“ - -7> / - “I - ‘ - 1- , . 3 ,1, . _- L (5) -- - I , - - N - . L (2) ‘ f ; if? . 1- gws : - , - , ~ . - I..- - =~ ‘3 (6) , "I __ \ o; - - “I , ; I 1 - $1 I . T I ‘ - i I I I - ‘ 1 I I 0.2 I - - - 1 I - I — > : I I I I T I I I I I - ‘ I '- I I - - , - - ; -1 . ..-._ --...,- ,, i ; I I 1 . - 0.1L I, ,I , f . I 4 I. I - - I I f FT“: "" “T - - - - - I - , . I .I.-I -, L. ,1- ,, ‘- - I -‘ I I I J . I 0 0 IL I l l 1 l I _.L _;_._. . I "‘ I ' I I - I I I 1 f ' I I I Harvest Period-Two Weeks Interval 1 Mean of 4 Replicates. figure 20.--1Mean Root/Shoot Ration of E. odoratum from Seven Localities Calculated from Mean I5.andMean D Means :t SSE on Three Harvest Perio s. and their Weighted Localities 03-2.- ”.8an8 IT. H E. . - . e -. , r _ - , .J. 1, . H .4 1 F. - I.--I _-Ia-- II- M- -III-IIInIIIIIv . NII 1 FIT-I, .I I .w ,. - . , ,. _ 7 M u w 1 h . M I D. _ , - , ,. 1 . . m. I- IIIl-I- I, I i I III- - II III-1- . I f - . , - ,1. Ta A. U, G, O S I N G A H h. . - .m w _ o . . .. I u , 1 . T _ r . . . m m w 1 , . TIT-{II I v .I ' -I.\ IIIIA I I II I I I III II I» IIIIIII I. I? IIllVl ” L . , 1 1 . _ . H . _ W . _ _ . . s. 1 , 4 a; . “I ,- . I 0. n“ 0 IHI odoratum from Seven Localities. figure 21.--Means of Root/Shoot Ratio #82 Over Three Sampling Periods in E. II 'I‘IIJIII III. I’ll: 69 Root weight ratio (RWR).--Root weight ratio varied among plants from the seven localities. Differences among plants were significant at both sampling intervals except in plants from Thailand and Sango Otta. Plants from Thailand had the highest ratio (0.405), and those from Trinidad had the lowest ratio (0.237) (Figure 22). There was no apparent change in root weight ratio in plants from @ Thailand, Malaya, and Trinidad at both sampling intervals; E'- the others showed significant decrease in root weight [ ratios at the second sampling interval. Plants from the Old World Tropics had higher root weight ratio than plants from the New World Tropics. Leaf area (LA) and leaf area ratio (LAR).--Leaf area increased in plants from Thailand, Agege, and Guatemala at all sampling periods; however, plants from Malaya, Sango Otta, Trinidad, and Florida showed a decrease in leaf area at the third sampling period. Plants from Guatemala had the largest leaf area and differences between sampling periods and among the other plants were signifi— cant. Increase in leaf area in the plants from Guatemala parallels the increase in dry weight (Figures 23 and 24). The correlation between total dry weight and leaf area at all samplings was found to be highly significant at P < 0.01; r = 0.907 (n = 21). There were no significant differences among plants from the other areas except IPigure 22. --Means of Root Weight Ratio of E. over Two Sampling Intervals. 7O E 13; il‘a+l’1“3f.-s.a§ Edi Wfll LOCALITIES odoratum Loca o xl +7 9 "I: a: gig 9.1L ~27 ‘ - ”J H V S S“ _._ o 4‘ ' l. or 3. 15 __ THLD Anna) AHSO 6037' TRIO» PLxD liti”? lllll 111:! I'll ll l..lllll 71 Y x t H LeaLArearcmzrxrlflfl p—a , . 1 Mean of 4 Replicates. 11gure23.--1Mean Leaf Area (cm2) of E. odoratum from Seven Local- ities Over Three Sampling Periods. Leaf Figure 24.-~Means of Leaf Area (cm2) of E. odoratum from Seven .Localities Localities over Three Sampling Periods. 73 Sango Otta, at the second sampling period, and Agege, at the third sampling period. Weighted means over three sampling periods is pre- sented in Figure 24. There were significant differences among plants from all the areas investigated. Except for the plants from Thailand, those from the Old World Tropics had larger leaf area than those from Trinidad and Florida. Leaf area ratio varied between plants at all sampling intervals. Leaf area ratio was highest in the plants from Trinidad and least in those from Sango Otta. Mean leaf area ratio over two sampling intervals is shown in Figure 25. Except in the plants from Malaya, plants from the Old World Tropics had lower leaf area ratio than those from the New World Tropics. All differences were significant at P < 0.05. There were little or no differ- ences in the plants from Agege and Sango Otta at both sampling intervals; differences among plants from other areas were however significant. Net assimilation rate (NAR) and relative growth rate (RGR).--Results of net assimilation rate and relative growth rates are summarized in Table 2. There was no overall significance between sampling intervals in both net assimilation and relative growth rates. Differences among plants from the seven localities were however significant. Plants from Thailand had the highest net 74 E ‘ Jctflntervql . 2nd. I» 1&— 9 PE“; :3 __ r-flj C; '1 6 a a: (“if 0 u. <[ Lu _J 3 r + - zeal. "—1 ‘41 H1 0 J Tut—o Mu/A m Fa T LOCALITZIES ' All... Figure 25. --Mean Leaf Area Ratio (cm2 /gm) .Over Two Sampling Intervals and their Range in E. odoratum from Seven Localities. ,I‘ 7S H00.0I mmH.0| vm0.0| Hm0.0l 000.0: «no.0: exam 000.0 0N0.0| mvo.0 HH0.0 mm0.0| mh0.0 sze NOH.0 mmH.0 000.0 mma.0 mnH.0 m00.0 B¢Do 050.0 00H.0 mm0.0 500.0 00H.0 0m0.0 OmHz vHH.0 05H.0 «m0.0 mHH.0 Hma.0 0m0.0 wfiHz Nm0.0 5H0.0| NNH.0 HOH.0 0N0.0| mNN.0 «MAS HNH.0 mmm.0 m00.0 00H.0 mom.0 000.0 Gama com: N H qmmz N H mmfluwamooq Hm>umucH mcflamamm am>umunH mafiamfimm Esmsov maz 235353 omo .mHm>Hmusw mqeamsmm ozu Hm>o mmfluflamooH cm>mm Scum Edumuono .m ca .AEm\mEUV mumu coflumafififlmmm um: cam .x3\Em\Em mmmu npzoum m>HuMHOMII.~ mqmde 7O assimilation rate of 0.121 cmZ/gm, and those from Florida had the least net assimilation rate of-0.128 cmZ/gm. Increase in net assimilation rates was observed in plants from Thailand, Agege, Sango Otta and Guatemala over the sampling intervals. There was an increase in relative growth rates in the plants from the Old World Tropics except those from Malaya. Increase in relative growth rate occurred only in plants from Guatemala in the New World Tropics. Differ— ences between sampling intervals were significant in plants from all the localities investigated. There were signifi- cant differences also among plants from the seven locali- ties by making use of the mean relative growth rate over two sampling intervals. Plants from Guatemala had the highest relative growth rate of 0.133 gm/gm/wk and those from Florida had the least of -0.051 gm/gm/wk. Correlation with habitat factors.--A summary of simple correlations is shown in Table 3. Only RGR was significantly correlated with mean annual rainfall. It was expected that high correlations would be obtained with respect to latitude and longitude and perhaps temperature. It did confirm, however, that variations and differences among the plants may be due to available moisture in specific localities. 77 TABLE 3.--Simple correlation coefficient with climatic features of growth attributes of E, odoratum from seven localities. Mean Mean Lat. Long. Ann. 0C Ann. rainfall LAR +0.27 +0.53 +0.33 +0.35 NAR +0.51 +0.18 +0.20 +0.60 RWR +0.31 +0.30 +0.20 +0.47 RGR +0.67 +0.08 +0.36 +0.75* * significant at P<0.05. 78 Effect of Moisture Dry weight.--Results of the effect of soil moisture on total dry weight accumulation are summarized in Figure 26. There were significant differences between treatments and among plants from the seven localities investigated. Total dry weight accumulation among plants from these areas was less at temporary wilting point than at either field capacity or saturated point. At the two extremes of moisture conditions, plants from the Old World Tropics had larger total dry weights than those from the New World Tropics, excluding plants from Guatemala which had the largest total dry weight of 17.92g at saturated point and second largest total dry weight of 17.95g at temporary wilting point. Although no clear pattern was observed among plants from both the New and the Old World Tropics at the two extreme moisture conditions, plants from four localities--Thailand, Malaya, Guatemala, and Trinidad—- however showed increase in total dry weight at saturated point, while there was a decrease in total dry weight in plants from all localities at temporary wilting point. Root/shoot ratio.--Figure 27 shows the effect of moisture on root/shoot ratio in plants from seven areas investigated. There were significant differences in root/shoot ratio among the plants from all localities at three moisture conditions. Differences were due to the 79 .mpofluwm mcflautmm omuxb um mm A memo: omucmewx peony paw maw>oq ousumeoz OOHLB um mmeuflamooq co>om Eouw EsOQHOUo .m we ugmemz >uann.mm wuswflm Hm>uwucH mxmmz O3BI©oflumm umw>umz omqmlmrmvu ozmeLVLVI emowlvill omHzL1L1| omA musumfloz wanna um mmflufiamooq cm>mm Eouw Edumuowo .w wo oflumm poocm\uoomun.nm wusmflm Hm>uwucH umm>umm Hm>umucH umw>umm Hm>umucH umw>nmm m o H m h A a? m r H. OI x 01393 acous/aoou IDIUIQmJE . ITumufim mcHHmEmm 038 um>o maw>mq mHsumwoz mouse um mmfluflamooq cm>om Eoum EduMHOUO .m CH mam 0cm mHmch mucmfipmmnfi mcHHmEmm mmHuHHMUOH cm>mm .mmHuHHMUOH mmmuum musumHoE woman um Eonw ESDMHOUO .m :H Ax3\Em\Emv mnmu QDBOHm m>HuMHmmll.v mqmda ucHom mcHuHHz mummomfimu Haze m suflommmu oflmflm 0 ohm DGHOQ coHp0H5u0m u mmH mm0.0| 5m0.0| 000.0: 0m0.0 N50.0| NmN.0| voH.0 cam: mmo.0| mNH.0I 000.0: 0HH.0 H5H.0a 050.0 mH0.0I N mZB 0m0.0| Hm0.0 000.0 m00.0 0N0.0 mmm.0l HN0.0 H m mH0.0| mH0.0 000.0 0N0.0 0H0.0 000.0 N00.0 cam: 0H0.0: 000.0: m00.0 0H0.0: 5H0.0 m00.0| N00.0: N om NH0.0I 0m0.0 500.0 0m0.0 0H0.0 0H0.0 500.0 H N 500.0: 0H0.0 m00.0 H00.0 000.0 HN0.0 mm0.0 cmmz H00.0| 0H0.0 m00.0 Hm0.0u NN0.01 0H0.0 00H.0 N mm 0H0.0: NN0.0 000.0 mmH.0 Hm0.0 5N0.0 0H0.0 H H QmHm Dzmfi Edam OmHz 04:2 4552 01.59 Hm>HmuGH uamEummHB mCHHmEMm I .mmHuHHmooH mmmnum mnsumHoE mmnzg um mmHuHHmooH cm>mm Scum Edumwopo .m CH Ax3\NEo\Emv mama cOHpMHHEHmmm umZnu.m mqmda 86 variance for each treatment showed that differences among plants from all areas were significant. Net assimilation rate varied among the plants at the two extremes of mois- ture treatment. The plants from Thailand had the highest net assimilation rate at temporary wilting point and second only to those from Sango Otta at saturated point. Relative growth rate varied also among plants from the seven areas investigated. Plants from Sango Otta had the highest relative growth rate at saturated point followed by those from Thailand (Table 4). All plants showed reduced growth rates at temporary wilting point. Effect of Nitrogen Results of the effect of nitrogen on plant height, number of leaves per plant, total dry weight, root/shoot ratio, leaf area, leaf area ratio and total nitrogen are presented here. Plant height and number of leaves per plant.--There were no marked differences in height and number of leaves per plant among plants from the seven areas investigated in the control and nitrogen treated plants (Figures 29 and 30). Nitrogen appears to have no effect on plant height and number of leaves produced per plant under the conditions at which the investigation was carried out. Significant differences in plant height and number of leaves could not 87 .man 50000002 cum; 09.0yre mmflufl cwmompgn 5003 0000000 mmflnfl uHmooq cw>mm Eoum Enumuovo .m 00 nHmooq cw>mm Eouh Edumuopo .m ucmHm boa mm>woq mo umoesz cmmznt.0m mudem mo ucmHm Mom AEOV ustmm cmmzll.mN musmHm wwHuHHmooq . meuHHmooq qua exam 02mm egao omHz omHz wm Eoum mmuamHmS paw A500 unmflmx who Hmpos so ammougHz mo pommmmlu.Hm muumHm 90 treatments, plants from some areas, however, showed signif- icant differences between treatments over three sampling periods. Excluding the plants from Malaya and Agege, plants from the others had lower root/shoot ratios under nitrogen treatment than in the control. Also, root/shoot ratios were higher in plants from the Old World Tropics in the control and treated plants than in those from the New World Tropics (Figure 32). Total nitrogen.--Total Kjeldahl nitrogen per unit of dry weight was higher in the treated plants than in the control. There were significant differences among plants from each area and between treatments. While there was generally an increase in total nitrogen in the treated plants from some areas, there was a decrease in total nitrogen in the control plants from four of the seven localities (Figure 33). Total nitrogen in the treated plants over three sampling periods showed that plants from Trinidad and Florida had about twice as much nitrogen as present in those from the Old World Tropics. This was not the case however in the control. Also, total nitrogen in plants from the New World Tropics in the treated plants was about twice as high as in the controls. For example, plants from Trinidad had a total nitrogen of 169.6 mg/g in the control and 240.4 mg/g in the treated plants. 91 meuHHmooq cm>mm Eonm Eduauouo .m :H mUoHHmm mcHHQEmm mouse um oflumm uoonm\uoom so ammouuflz mo uommmmsu.mm mnsmflm n t. (.. v. m E HG» _ _ m Mv U m N 93 Leaf area and leaf area ratio.—-The data for leaf area and leaf area ratio are summarized in Figures 34 and 35. Although leaf areas in the nitrogen treated plants were generally larger than in the control, there was no significant difference between treatments. Significant differences between sampling periods and treatments were observed however. Plants from Guatemala (867.7 and 941.7 cmz/g) had the largest leaf area at both treatment levels (Figure 34). Variations in leaf area among plants from each locality were observed. Plants from the New World Tropics had larger leaf area than plants from the Old World Tropics between sampling periods and treatments. There were significant differences in leaf area ratio among plants from the seven localities and between treatments. Leaf area ratio in the nitrogen treated plants were higher in those from the New World Tropics than in those from the Old World Tropics. No apparent effect of nitrogen on plants from Malaya was evident as a lower leaf area ratio (59.6 cmz/g) was obtained in the nitrogen treated plants than in the control (73.2 cm2/g) (Figure 35). Variations in leaf area ratio were also evident. The range between the two sampling intervals was fairly uniform among some plants from areas in the control, but varied considerably among others in the treated plants. l .mpoHHmm msHHmEmm gonna um Edumnopo .m :H ANEOV mwum mqu so cmvouqu mo uommmmul.vm onsmHm .mHm>vacH mcHHmEdm O39 um>o moHpHHmooq cm>wm Eoum ESDmuopo .m CH Eb Eu oHumm mmud mama Gmmzll. mudmam N mm . 96 U 5 Plant; /P0‘0 T m 6 u “ T /'\ W \J (t g 0 l . -- EL. L l 1% T lil I ”L TEN H [5‘ “I " | "' J IL! 9( I 7 g: , < Hi ' 12- 'i .4 5;. H 1_L _ h .__l Limits L_ raw Mic/n MAS M'SD . GMT 7M0 P1410 Lo CA LIT/ES Figure 36;--Average Height Per Plant (cm) 1 Si of E. odoratum from Seven Localities at Two Density Levels of Three and Six Plants Per Pot. 97 Nitrogen did not appear to have any definite effect on growth and development of E. odoratum. Incre- ments and variations in leaf area, leaf area ratio may be due to nutritional effect only. Observation on the effect of nitrogen on germination supported the idea of nutritional effect. Increase in surface area of cotyledons and early development of the primary leaves with increasing nitrogen concentration were observed. Further investiga- tion of the effect of nitrogen in the field may help con- firm the nutritional role as well as any other role the nitrogen may play in the growth and development of E. odoratum. The early phases of seedling development may be considered also. Effect of DensiEy Results of the effect of density on the behavior of E. odoratum are presented here. The response of plants from the seven localities was different in each of the growth attributes examined. Height and number of leaves per plant were significantly different among plants and between treatments. Total dry weight and net assimilation rate were much higher at low plant density level than at the high plant density level. Root weight ratio, however, was generally larger at the high plant density level than at the low plant density level. 98 Plant height and number of leaves per plant.-— Plant heights in four populations from Malaya, Sango Otta, Guatemala, and Trinidad were greater at the low plant density level than at the high plant density level. Plants from Thailand were taller at the high plant density level than at the low plant density level. Plant heights were slightly greater in those from Agege and Florida at the high plant density level than at the low plant density level (Figure 36); differences were not, however, signif- icant. Variations within the plants from each area at both density levels were evident. The average number of leaves per plant (Figure 37) was generally greater in plants at the low density level than at the high density level. Variations within the plants from Malaya (17.6 i 2.35), and Guatemala (27.40 i 5.79) were highly significant at the low density level. The average of leaves per plant was largest in plants from Guatemala at all samplings. Differences among plants from each area were significant at the two density levels. The average number of leaves per plant appears to be related to the height. There was an inverse relation- ship between height and number of leaves in plants from Agege, Sango Otta, and Florida. Dry weight.--Total dry weight was generally higher at the low density level than at the high density level; 99 ’Localities- Figure 37.--Average Number of Leaves Per Plant 1 Sx in E. odoratum from Seven Localities at Two Density Levels of Three and Six Plants Per Pot Respectively. 100 plants from Florida, however, had significantly higher total dry weight at the high density level than at the low density level. Plants from two areas of the Old World Tropics had significantly lower dry weight at the high density level than at low density level. Excluding the plants from Guatemala with highest mean dry weight (3.55g), plants from the Old World Tropics in general had higher total dry weight at the low density level than those from the New World TrOpics (Figure 38). Plants from two areas of the New World Tropics had significantly higher dry weight at the high density level than those from the Old World Tropics. In plants from Florida, the mean dry weight at high density was more than twice as great as at low density level; whereas, there was no difference at the two density levels in the plants from Thailand. Mean dry weight was about twice as high at low density level as at high density level in plants from other areas . Root/shoot ratio.—-Results of the effect of density on root/shoot ratio are summarized in Figure 39. Root/ shoot ratio was greater at high density level than at low density level. There was no overall significant differ— ences among plants from each area at the two density levels. There were significant differences among plants from each locality, however, between samplings. 101 IHmoaq Cubmm Eoum F.. n;5. .m CH 00m 0 mHmioA mu- 1 ;,. 40 mmeH .me>mq NpamCmn 005 um ,wHuHHmooq Cm>mm Eouw EDLmHOCO .m CH C H00 uCMHm Cwm OHumm uc:£m\uoom Cmmzin.0m mustm pom umm uCMHm Hmm quHwB hum Cwmzln. mm m. Pot _ .BerlPlant re '7‘— Root/ Shogt Rat A . _ . L i 3 ”0mewame .0 u a. _ ‘5’. 000?»:me m .n 0?: . l “ n l TL: L. 102 Root/weight ratio. --Root weight ratio was greater at high density level than at low density level in plants from six of seven localities investigated (Figure 40). There were significant differences among the plants and between treatments. As root weight ratio is based on total dry weight, it appears to offer a meaningful explanation as to the behavior of the roots in dry matter accumulation in E. odoratum. Although root weight ratio was higher at higher density level than at low density, it did not appear that intraspecific competition is sufficiently high to inhibit growth and development in plants from the different areas. Interpretation of this result may be taken with caution in that two samplings may not be sufficient to explain the true behavior of this Species at high density level. It is therefore suggested that further investi- gation of density levels be carried out in the field to determine the degree of interaction within plants from different areas as well as among other species. Leaf area ratio.-—In plants from Thailand and Agege leaf area ratio was higher at high density level than at low density level; in plants from Malaya and Florida, leaf area ratio was higher at low density than at high density. Differences between the two treatments were significant in plants from the four areas listed above. There were no significant differences in the rest of the plants from other areas at the two treatment levels (Figure 41). 103 J Illlllll flflflflllulllilllllillllllllllHiiillll! I. 'lllrllllllrlll||.llll .. . . 4 O 15.. 01311.95?”an ‘ "[3311 n sl’PergPdt‘j 17 I. T a u: 1] 1: r n , V . u .L . r . 4... . r . .c! y -1 . o , _ L odoratum from Seven Localities at Two Density Figure 40.--Root Weight Ratio (Gm Gm_l) Per Plant of E. Levels of Three and Six Plants Per Pot. 1: PE USA? ”41 n1: per 1 m e l /9 egrpga 104 a” -T ~ (:1 '3ffladF<* NO If ’8’ 8 8‘ M Ma ~05 mso 0M?” he mo Lockhtftis Figure 41.-~Leaf Area Ratio cm 2/gm Per Plant Per Pot of E. ‘odOratum from Seven Localities at Two Density Levels of Three and Six Plants Per Pot Respectively. 105 Relative growth rate and net assimilation rate.-- The contribution of leaves to growth may be impaired at high density level. Evidence for this was seen in low relative growth and net assimilation rate (Table 6). The rate of carbon assimilation did not depend on the size of the photosynthetic apparatus. It appears that the rate of carbon assimilation was much less than the rate of respiration; consequently, a negative net assimilation rate and relative growth rate among plants of the New World Tr0pics particularly at high density level. The develop- ment and growth of the plants in general seem to depend on how much dry matter was accumulated and how much was used up in supplying energy for growth. The data suggest that at high density level, a much larger amount of energy was required for growth. Discussion.--The data obtained in this investi- gation have shown the presence of physiological variations and also variations due possibly to experimental errors, etc., in Eupatorium odoratum grown under uniformly controlled environment and under some features of the environment. There were significant differences between plants from the different areas in dry matter accumulation, root/shoot ratio, root weight ratio, relative growth rate, and net assimilation rate. Marked differences were also seen 106 .mgmw>nmn 030 m0 uCMHm\uC@H03 5H0 H60 -0 uomxmLCMHm 0 M Q pom\mquHm m w m mmH.o- moa.o- HH.mHH 0em.o mme.a n 0000 000.0- Heo.ou 05.000 ema.o mem.a 0 000.0- «no.0- 00.0ma Hm~.o H50.H n 0209 HN0.0- mao.ou NH.HMH 0am.o mem.~ 0 000.0- N00.0- mo.vm He~.o m0m.0 0 9400 00m.o m0H.o 0~.0m mm~.o moa.e 0 500.0 eeo.o 0~.mHH 000.0 mom.H n omHz mvo.o 0mo.o «n.0HH mo~.o ~¢H.m a 500.0 Hmo.o mm.o¢H m-.o ~m~.H 0 04Hz eea.o 0~H.o me.eoa ooo.o woe.a 0 000.0- moo.ou 00.0HH mm~.o mee.a a «was eao.o mmo.o mm.Ho~ mmH.o mmm.m m mvo.o- mmo.o- mm.0mH «mmeo mom.H 0 name 0H0.0 000.0 00.0H 0H~.o mnm.H 0 Hang «“20 .20 Hume Huz0 .20 Huz0~.zo H.20 .20 1200 coeumasmom C42 m0m mag 03C 3H l .mHm>mH muHmCov 03» um Edumuoco .m mo mCOHuMHsmom Cm>mm mo much COHumHHEHmmm umC 0C0 .mumu Cuzonm w>Hu0HwH .OHumu mmum mmmH .OHumu quHmz noon .usmHmz aha Hmuoall.0 wands 107 among plants from these areas in response to some features of the environment and in particular to moisture. Root weight ratio, leaf area ratio, and net assimi— lation appear to be genetically controlled in E. odoratum. The significant differences and variations observed among plants in these growth functions suggest that they may represent physiological adaptations to features of the environment. Correlations between net assimilation rate, leaf area ratio, and root weight ratio were significant among plants from the different areas. Relative growth rate and net assimilation rate were also highly correlated. Differences in net assimilation rate and leaf area ratio were also closely associated. In plants grown under uni- form greenhouse environment, or, under extreme moisture conditions, high leaf area ratio was accompanied by low net assimilation rate, or vice versa. Generally, plants from the New World Tropics had high leaf area ratio and low net assimilation rate; plants from the Old World TrOpics had low leaf area ratio and high net assimilation rate (Figures 42 and 43). No definite pattern was established under high density effect; some populations had high leaf area ratio and low net assimilation rate. The inverse relationship between leaf area ratio and net assimilation rate observed in E. odoratum was similar to the findings of Watson (1947, 1952), and I '21 {I’ll 1" Ill if A R CM‘VGME 60 .4 6 «an. IDLAW! . M 108 :09 J. t-THJ’ s-Nmo 4.-Mso 5-GUAT éfiTflNb nib-8 ‘1 W9 23' WW I I m . 191(9), 20'}: ‘1' ‘XM/ 4:55 5 10 - 36‘ Wfiytr ..._..'_1._.__.._ . ”-0..- Figure 42.--Relationship Between Relative Growth Rate, Net Assimi- lation Rate, and Leaf Area Ratio in E. odoratum from Seven Localities (Means and their Range over Two Sampling Intervals). i l i I i . 1' . T 30;... I; Localities i ’ ‘ .1 A" 1 110 Wilson and Cooper (1969). Hammerton (1965) attributed differences in net assimilation rate to differences in leaf fall, which may affect the estimates of leaf area ratio and net assimilation ratein Polygonum persicaria. In E. odoratum, no leaf fall was observed during the period of investigation. Differences in net assimilation may be due to the size or the leaves, or to differences in the rate of respiration which may be higher or lower than the rate of photosynthesis. It has been reported by Bjorkman and Holmgren (1961) that differences in respiratory rates and the rates of photosynthesis occurred in ecotypes of Solidago virgaurea. Root weight ratio as a function of an estimate of the contribution of root to growth was found to vary among plants from the different areas investigated. Increase in root weight ratio was accompanied by a decrease in leaf area ratio as seen in plants grown under uniform greenhouse environment or under extreme moisture conditions. Root weight ratio was generally higher among plants from the Old World Tropics than those from the New World Tropics. The fact that plants from the Old World Tropics produced more root in proportion to the dry weight than plants from the New World Tropics may suggest that this attribute is an adaptation of the plants in the Paleotropics to different habitats in which they grow. Significant differences in root weight ratio among the plants from the Old World lll Tropics may perhaps reflect the plastic nature of the genotypes that have been produced in these areas. It appears that significantly higher root weight ratio in some plants may be in response to the effect of density; or, it may be due to the experimental techniques employed. Correlation with habitat factors suggests that physiological differences may be associated with precipi- tation, consequently, the populations of E. odoratum may be thought of as representing climatic ecotypes. The lack of correlation of the growth functions with such features as longitude, latitude, and temperature did not imply that these factors have no effect on growth and development of E. odoratum. It may be that the behavior of the plants under uniformly controlled conditions was masked in such an environment. The plants from Agege and Sango Otta differed in their response to the effects of moisture and density in some of the growth functions investigated. The affinity of the plants from Thailand to that from Agege may suggest that introduction of E. odoratum to Nigeria was from Thailand; also some similarities between plants from Malaya and Trinidad may indicate that introduction into Malaya was from Trinidad. It may be suggested that plants from the Old World Tropics represent separate introductions. 112 The introduction of E. odoratum in the Old World Tropics in recent years is seen in its physiological diversity which has helped it to be a successful species in a wide range of habitats. It is envisaged that further research will be carried out in the field to ascertain the results that have been obtained from the various greenhouse experiments. Such investigation must include seedling F3 establishment, efficiency in the utilization of mineral nutrients, inter- and intraspecific competition, and reproductive biology. GENERAL DISCUSSION The results obtained from germination and growth studies of E. odoratum from the New and Old World Tropics suggest that several different genotypes are represented in these different areas. The conditions necessary for the evolution of ecotypes within a species have been sum- marized by Bradshaw (1959). The physiological variations observed in this investigation appear to be genetically controlled, because they were observed under uniformly controlled environmental conditions; it is reasonable to assume such variations to be adaptive. Correlation of growth functions and percent germi- nation with mean annual precipitation in locality of origin may lead one to conclude that moisture is perhaps one of the features of the habitat that has acted as a selective force to which adaptations have been made. Furthermore, significant differences have been found in some morphologi- cal characteristics in plants of E. odoratum from Nigeria growing along a moisture gradient (Edwards, 1969). That there is a correlation between a growth attribute and a habitat factor does not necessarily indicate a causal relationship, nor does it demonstrate the adaptive value of that particular attribute. As Bradshaw (1959) has 113 114 pointed out, a population may appear unrelated to its environment because our assessment of the environment is at fault, or the factor involved may no longer be operative. When seeds are introduced into a new habitat, only those that are suited to the prevailing conditions will germinate and produce offSpring. Suitability depends upon the adaptive features that have evolved within the Species. Therefore, variations occurring in these adaptive features under changes in environmental conditions may indicate the degree of plasticity of these features. The characteristic ability of seeds of E. odoratum to germinate readily under varying moisture conditions suggests the plastic nature of the genotype in this respect; unlike some species of temperate climates whose seeds will not germinate unless at optimum conditions of particular environmental factors (Harper and Benton, 1966; Harper and Sagar, 1963; Harper §E_§l,, 1963). This characteristic ability to germinate readily is thus considered an asset in E. odoratum that enables it to compete with other species whose seeds do not have this adaptive value. It is perhaps in the establishment and growth phases that the ultimate survival of the species depend. E. odoratum is a Species that has been introduced into more or less stable or seral communities in the Old World Tropics. For a species to be successful in such a com- munity, its genetic program must allow it to operate 115 within an array of environmental conditions. It has been argued (Cody, 1966; Harper, 1967; MacArthur and Connell, .1967) that the manner in which the resources of an organism are apportionedcm:manipulated may be important in establish" ment and success of plant species. This concept may be applied to examining the behavior of plant Species intro- duced into stable or seral communities. It appears that in I. odoratum some physiological adaptations have contributed to the survival of the species in the Old World Tropics. These physiological adaptations are seen in the photo- synthetic mechanisms and in the allocation of energy to root production at the expense of shoot growth or leaf expansion. These characteristic features have been shown to be sensitive to features of the environment (BjBrkman and Holmgren, 1963; Cooper, 1963) in a manner suggesting adaptive significance. There is sufficient evidence to conclude that the physiological attributes and characteristic features observed in germination and growth of E. odoratum have contributed to the success and rapid distribution that have been observed in populations from the Old World TrOpics. These physiological attributes may also have contributed to the aggressiveness of the species. The characteristic efficiency of the root system, the shoot system, and high net assimilation rate appear to have been a few of the pathways selected by the genotypes introduced 116 into the different habitats in the Old World Tropics. The variations observed in plants from the three localities from Nigeria suggest the influence of the microhabitats on the plants in which the species became established. Plants from each of these areas apparently are of different genotypes. The ecological success of E, odoratum in becoming a wideSpread species in the Old World Tropics may be attributed in part to its characteristic germination and growth behavior in response to some factors of the environ- ment. Perhaps of much significance is the characteristic behavior in allocation of energy and materials during the growth phase of the Species. The absence of predators also may have enhanced the develOpment of adaptive physio- logical features in approximately fifty years of the species' introduction into the Old World Tropics. Further- more, these physiological adaptations and the absence of predators may have contributed to the species competitive capacity within the communities in which it is found. SUMMARY Physiological attributes of germination and growth response in E. odoratum from seven localities of the New and Old World Tropics have been investigated under uni- formly controlled environmental conditions. Significant differences were found among seeds from the seven localities in rate of germination, percent germination, and in time to reach maximum germination. Also, variations and differences in growth functions were found to be significant among plants from the areas investigated. Ecological success of an introduced Species in new and alien habitats is discussed. 117 REFERENCES 118 REFERENCES Adams, C. D. 1964. New records of flowering plants in West Africa. V. Compositae. J. W. Afr. Sci. Ass. 8:127-133. Allard, R. W. 1965. Genetic systems associated with colonizing ability in predominantly self-pollinated species. pp. 49-75. In H. G. Baker and G. L. Stebbins (eds.). The gEnetics of colonizing species. Academic Press, New York. Baker, H. G. 1965. Characteristics and modes of origin of weeds. pp. 147-172. £3 H. G. Baker and G. L. Stebbins (eds.). The genetics of colonizing species. Academic Press, New York. Baker, H. G. 1967. The evolution of weedy taxa in the Eupatorium microstemon species aggregate. Taxon l : 93—300. Bennett, F. D. and V. P. Rao. 1968. Distribution of an introduced weed Eupatorium odoratum Linn. (Compositae) in Asia and Africa and possibilities of its biological control. Pest Articles and News Summaries, Sec. C. 14:277-281. Bennett, F. D. and R. E. Crutwell. 1969. Host specificity tests with Amalo insulata (Walk) Arctiidae, a potential agent for the control of Eupgtorium odoratum Linn. Composiae. CIBC Unpub. Report. p. 9. Bhat, R. V. and M. G. Karnik. 1954. Indigenous cellulosic raw materials for the production of pulp, paper and board. India For. Bull. 182:1-9. Biswas, K. 1934. Some foreign weeds and their distribu- tion in India and Burma. Indian Forester. 60: 861-885. Bj6rkman, O. and P. Holmgren. 1961. Studies of climatic ecotypes of higher plants. Leaf respiration in different p0pulations of Solida o virgaurea. K. Lamtbr. Hogsk. Ann. 27:297-304. 119 120 Bjorkman, O. and P. Holmgren. 1963. Adaptability of the photosynthetic apparatus to light intensity in ecotypes from exposed and shaded habitats. Physiol. Plantarum. 16:889-914. Blackman, V. H. 1919. The compound interest law and plant growth. Ann. Bot. 33:353-360. Bradshaw, A. D. 1959. Population differentiation in Agrostis tenuis Sibth. I. Morphological differen— tiatIOn. New Phytol. 58:208-227. Bradshaw, A. D. 1965. Evolutionary significance of phenotypic plasticity in plants. Adv. Genet. 13:115-155. Briggs, D. and S. M. Walters. 1969. Plant variations and evolution. World University Library, McGraw-Hill Book Company, New York. Cavers, P. B. and J. L. Harper. 1966. Germination poly- morphism in Rumex crispus and Rumex obtusifolia. Cavers, P. B. and J. L. Harper. 1967. Studies in the dynamics of plant populations: the fate of seed and transplants introduced into various habitats. J. Ecol. 55:59-71. Chatterjee, B. N. 1961. Analysis of ecotypic differences in tall fescue (Festuca arundinacea Schrieb.). Ann. Appl. Biol. 49:560-562. Chesseman, E. E. 1940. Flora of Trinidad and Tobago. Vol. 2 pt. 2 (Asterales). Trinidad Govt. Printer, Port—of-Spain, Trinidad. Cody, M. L. 1966. A general theory of clutch size. Evolution 20:174-184. Cohn, R. J. and C. L. Kucera. 1969. Photoperiodic adap— tations in Egpatorium rugosum. Amer. J. Bot. 56: 571-574. Cole, N. H. A. 1967. Comparative physiological ecology of the genus Eriogonum in the Santa Monica Mountains in southern California. Ecol. Monogr. 37:1-24. 121 Cooper, J. P. 1963. Species and populations differences in climatic reSponses. pp. 381-403. In L. T. Evans (ed.). Environmental control of_plant growth. Academic Press, New York. Cooper, J. P. and J. R. McWilliam. 1966. Climatic varia- tion in forage grasses. II. Germination, flowering and leaf development in Mediterranean populations of Phalaris tuberosa. J. Appl. Ecol. 3:191-212. Crutwell, R. W. 1968. Preliminary survey of potential control agents of Eupatorium odoratum in Trinidad. Proc. 9th Brit. Weed Control Conf. pp. 836-841. Crutwell, R. E. 1969. Report on a survey of the insects associated with E. odoratum L. in Central America, undertaken in June—July, 1968. pp. 12 (CIBC Unpub. Report). Crutwell, R. W. 1970. Report on studies of Apion brunneonigrum B.B. a weevil attacking Eupatorium odoratum L. (Compositae) in Trinidad. pp. 8 (CIBC Unpub. Report). Crutwell, R. E. 1971. Report on a survey of the insects associated with Eupatorium odoratum L. in South America, undertaken in April-May,T197l. CIBC Unpub. Report. pp. 14. Eagles, C. F. 1969. Time changes of relative growth rate in two natural populations of Dactylis glomerata L. Edwards, A. W. A. 1968. First progress report on distri- bution of Egpatorium odoratum L. in Southern Nigeria. Fed. Ministry Agric. Unpub. Report. pp. 4. Edwards, A. W. A. 1969. Second progress report on dis- tribution and growth of Eupatorium odoratum L. Fed. Ministry Agric. Unpub. Report. pp. 5. Edwards, A. W. A. 1969a. On the ecology of Eupatorium odoratum L. I. Distribution and growth in fourteen localities in southwestern Nigeria. Paper read at the 9th Annual Conf. of Science Society of Nigeria, Zaria, 1969. 122 Grashoff, C. 1969. Reproductive processes affecting the taxonomy of some Mexican and Central American Species of Eupatorium. Thesis: Master's degree. Michigan State Univ. pp. 101. Hammerton, J. L. 1965. Studies on weed species of the genus Polygonum L. I. Physiological variation within E. perSiCaria L. Weed Res. 5:13-26. Hammerton, J. L. 1967. Studies on weed Species of the genus Polygonum L. IV. Variations in seed weight and germination behaviour in P. lapathifolium. Weed Res. 6:1-21. ‘ Hammerton, J. L. 1967a. Studies on weed species of the genus Polygonum L. V. Variations in seed weight, germination behaviour and seed polymorphism in E. persicaria L. Weed Res. 7:331-348. Hammerton, J. L. and M. Stone. 1966. Studies on weed species of the genus Polygonum L. II. Physiologi- cal variation within P. 1apathifolium L. Weed Res. 6:104-131. ‘ Harper, J. L. 1965. Establishment, aggression and cohabitation in weedy species. IE.H° G. Baker and G. L. Stebbins (eds.). pp. 243-268. The genetics of colonizing species. Academic Press, New York. Harper, J. L. 1967. A Darwinian approach to plant ecology. J. Ecol. 55:242-270. Harper, J. L. and R. A. Benton. 1966. The behaviour of seeds in soil. II. The germination of seeds on the surface of a water supplying substrate. J. Ecol. 54:151-166. Harper, J. L. and A. P. Chancellor. 1960. The comparative biology of closely related species living in the same area. IV. Rumex: Interference between indi- viduals in populat1ons of one and two species. J. Ecol. 47:679-695. Harper, J. L. and I. H. MacNaughton. 1960. The inheri- tance of dormancy in inter— and intraSpecific hybrids of Papaver. Heredity 15:315—320. Harper, J. L. and J. Ogden. 1970. The reproductive strategy of higher plants. I. The concept of strategy with Special reference to Senecio vulgaris L. J. Ecol. 58:681-698. 123 Harper, J. L. and G. R. Sagar. 1963. Some aspects of the ecology of buttercups in permanent grasslands. Proc. Br. Weed Control Conf. 1:256—264. Harper, J. L., J. N. Clatworthy, I. H. MacNaughton, and G. R. Sagar. 1961. The evolution and ecology of closely related Species living in the same area. Evolution 15:209-227. Harper, J. L., W. T. Williams, and G. R. Sagar. 1965. The behaviour of seed in soil. I. The heterogeneity of soil surfaces and its role in determining the establishment of plants from seeds. J. Ecol. 53:273-286. Hutchinson, J. and J. M. Dalziel. 1963. Flora of West Tropical Africa. 2nd ed. Vol. 2. Crown Agents, London. Knipe, D. and C. H. Herbel. 1960. The effects of limited moisture on germination and initial growth of six grass species. J. Range Manage. 13:297-302. Kucera, C. L. 1958. Flowering variation in geographic selections of Eu atorium rugosum. Houtt. Bull. Torrey Bot. Club. 83:40-48. Kucera, C. L. 1962. Racial studies on Eupatorium rugosum Houtt. Adv. Front. P1. Sci. 1:75-86. Lazenby, A. 1955. Germination and establishment of Juncus effusus. II. The interaction effects of moiSture and competition. J. Ecol. 43:595-605. Lindsay, D. R. 1953. Climate as a factor influencing the mass ranges of weeds. Ecology 34:308-321. Litzenberger, S. C. and Ho Tong Lip. 1961. Utilizing Eupatorium odoratum L. to improve crop yields in Long, R. W. and O. Lakela. 1971. A flora of trOpical Florida. A manual of seed plants and ferns of southern pennisular Florida. University of Miami Press, Coral Gables, Florida. MacArthur, R. H. and J. H. Connell. 1967. The biology of populations. pp. 200. John Wiely and Sons, Inc., New York. 124 McKell, C. M., J. P. Robinson, and J. Major. 1962. Ecotypic variation in Medusahead, an introduced annual grass. Ecol. 43:686-698. McMillan, C. 1969. Photoperiod in three Xanthium popu- 1ations from the Tropic of Cancer 1n Mex1co. Science 165:292-294. McMillan, C. 1970. Photoperiod in Xanthium pOpulations from Texas and Mexico. Amer. J. Bot. 57:881-888. McMillan, C. 1971. Photoperiod evidence in the intro— duction of Xanthium (Cocklebur) to Australia. Science 171:1020-1031. McWhorter, C. G. 1971. Growth and develOpment of Johnson grass ecotypes. Weed Science 19:141-146. McWilliams, E. L., R. Q. Landers, and J. P. Mahlstede. 1966. Ecotypic differentiation in response to photoperiodism in several species of Amaranthus. Iowa Academy of Sciences 73:44-51. Millener, L. H. 1962. Daylength as related to vegetative development in Ulex europaeus L. II. Ecotypic variations with latitude. New Phytol. 61:119-127. Mohan Lal, K. B. 1960. Eradication of Lantana, Eupatorium and other pests. Ind. For. 86:482-484. Moni, N. S. and M. P. George. 1959. Eupatorium odoratum, a common weed found in teak plantations of Kerala State. Indian For. 85:728-730. Moni, N. S. and R. Subramonian. 1960. Essential oil from Eupatorium odoratum--a common weed in Kerala. Indian For. 86:209. Monk, Carl. 1966. Ecological importance of root/shoot ratios. Bull. Torrey Bot. Club. 93:402-406. Mulligan, G. 1965. Recent colonization by herbaceous plants in Canada. EE_H. G. Baker and G. L. Stebbins (eds.). The genetics of colonizing Species. Academic Press, New York. pp. 127-143. Odukwe, D. O. 1965. Eupatorium odoratum (Siam Weed). Bull. Nigerian For. Dept., April, 1964. Palmblad, I. G. 1969. Populational variations in germina- tion of weedy Species. Ecol. 50:746-748. 125 Peacock, J. T. and G. McMillan. 1968. Photperiodic response of American Proso is and Acacia from a broad latitudinal distribution. Amer. J. Bot. 55:153-159. Robertson, P. A. and R. T. Ward. 1970. Ecotypic differ- entiation in Koeleria cristata (L.) Pers. from Colorado and related areas. Ecology 51:1083-1087. Sakai, K. I. 1961. Competitive ability in plants: its inheritance and some related problems. Symp. Soc. Expt'l. Biol. 15:245-263. Sakai, K. I. 1965. Contributions to the problem of Species colonization from the viewpoint of competi— tion and migration. In H. G. Baker and G. L. Stebbins (eds.). The—genetics of colonizing species. Academic Press, New York. pp. 215—239. Salgado, M. L. M. 1963. New menace on coconut estates: Eupatorium odoratum spreads into coconut estate. Ceylon Coconut Planters' Review 3:69-70. Sheldrick, R. D. 1968. The control of Siam Weed in Nigeria. J. Nig. Inst. Oil Palm Res. 5:7-19. Shontz, J. P. and H. J. Oosting. 1970. Factors affecting interaction and distribution of Haplopappus divaricatus and Conyza canadensis in North Carolina old fields. Ecol. 51:780-793. Simmonds, F. J. 1965. Report on a visit to Sierra Leone, Ghana, Nigeria, Mauritius and East Africa. November 1964 - March 1965. Commonwealth Agri— culture Bureaux. pp. 42. (Unpub. Report). Snaydon, R. W. 1962. The growth and competitive ability of contrasting natural populations of Trifolium re ens L. on calcareous and acid soils. J. Ecol. 50:439-447. Springfield, H. W. 1966. Germination of four-winged saltbush seed at different moisture stress. Agr. J. 58:149-150. Stebbins, G. L. 1965. Colonizing species of the natural California flora. In H. G. Baker and G. L. Stebbins (eds.). The genetics of colonizing species. Academic Press, New York. pp. 173-195. J.‘ 126 Steinbauer, G. P. and B. Grigsby. 1957. Interaction of temperature light and moistening agent in the germination of weed seeds. Weeds. 5:175-182. Steinbauer, G. P. and B. Grigsby. 1957a. Dormancy and germination characteristics of the seeds of four species of Plantago. Proc. Assoc. Off. Seed Anal. 47:158-164. Steinbauer, G. B., B. Grigsby, L. Correa, and P. Frank. 1955. A study of methods for obtaining laboratory germination of certain weed seeds. Proc. Assoc. Off. Seed Anal. 45:48-52. Thurling, N. 1966. Population differentiation in Augtralian Cardamine. II. Response to variations in temperature and light intensity. Aust. J. Bot. 14:179-188. Thurling, N. 1966a. Population differentiation in Australian Cardamine. III. Variation in germina- tion response. Aust. J. Bot. 14:189-194. Timson, J. 1965. Germination in Polygonum. New Phytol. 64:179-186. Toole, E. H. and V. K. Toole. 1941. Progress of germina- tion of seed of Digitaria as influenced by germina- tion temperature and other factors. J. Agric. Res. 63:65-90. Toole, E. H., S. B. Hendricks, H. A. Borthwick, and V. K. Toole. 1956. Physiology of seed germination. Ann. Rev. Plant Physiol. 7:299-324. Turesson, G. 1922. The genotypical responSe of the plant species to the habitat. Hereditas 3:211-350. Turesson, G. 1925. The plant species in relation to habitat and climate. Hereditas 6:11-236. Uhvits, R. 1946. Effects of osmotic pressure on water absorption and germination of alfalfa seeds. Amer. J. Bot. 33:278-285. Ungar, I. A. and W. C. Hogan. 1970. Seed germination in Iva annua L. Ecol. 51:150-154. Vance, B. D. and C. L. Kucera. 1960. Flowering variations in Eupatorium rugosum. Ecol. 41:340-345. 127 Wareing, P. F. and L. D. J. Phillips. 1970. The control of growth and differentiation in plants. pp. 1?- 21. Pergamon Press, Oxford. Watson, D. J. 1947. Comparative physiological studies on the growth of fields crops. I. Variation in net assimilation rate and leaf area between species and varieties, and within and between years. Ann. Bot. 11:41—76. Watson, D. J. 1952. The physiological basis of variations in yield. Adv. Agron. IV:101-l44. Williams, J. T. and J. L. Harper. 1965. Seed polymorphism and germination. I. The influence of nitrates and low temperatures on the germination of Chenopodium album. Weed Res. 5:141-150. ' ‘— Wilson, D. and J. P. Cooper. 1969. Assimilation rate and growth of Lolium populations in the glasshouse in contrasting light intensities. Ann. Bot. 33: 951-965. Wycherley, P. R. 1960. Vegetation of rubber plantations. J. Rubber Res. Inst. Malaya. 16:87-92. Whycherley, P. R. 1963. The range of cover plants. Planters' Bull. Rubber Res. Inst. Malaya No. 68: 117-122. Whycherley, P. R. 1965. Ground covers in plantation crops. Symp. Ecol. Res. Humid Trop. Veg., Kuching, Whycherley, P. R. and M. M. Chandapilla. 1969. Effects of cover plants. J. Rubber Res. Inst. Malaya. 21: 140-157. General References Ayers, A. D. 1952. Seed germination as affected by soil moisture and salinity. Agron. J. 44:82-83. Boughey, A. S. 1968. Ecology of populations. The Mac- millan Company, Collier-Macmillan Ltd., London. 128 Bray, J. R. 1963. Root production and the estimation of net productivity. Can. J. Bot. 41:65-72. Edwards, K. J. R. and R. W. Allard. 1963. The influence of light intensity on competitive ability. Amer. Nat. 97:243-248. Collis-George, N. and J. E. Sands. 1959. The control of seed germination by moisture as a soil physical property. Aust. J. Agric. Res. 10:628—636. Hanson, H. C. and E. D. Churchill. 1961. The plant com- munity. Reinhold Publishing Corp., New York. Harper, J. L. 1961. Approaches to the study of plant competition. Ea F. L. Milthorpe (ed.). Mechanisms in biological competition. Symp. Soc. Expt'l. Biol. 15:1-39. Kormondy, E. J. 1969. Concepts of ecology. Prentice- Hall, Inc., Englewood Cliffs, New Jersey. McMillan, C. 1960. Ecotypes and community function. Odum, E. P. 1971. Fundamentals of ecology. 3rd ed. W. B. Saunders Co., Philadelphia. Solbrig, O. T. 1970. Principles and methods of plant biosystematics. The Macmillan Company, Collier- Macmillan Ltd., London. The Times Atlas of the World. 1967. Times Newspaper Ltd., London, and Houghton Mifflin Co., Boston. Varma, S. C. 1938. On the nature of the competition between plants in the early phases of their develOpment. Ann. Bot. N.S. 2:203-225. _- 4m.-. APPENDIX 129 .mpmmm mN mo mmCMOHHmmu quHm mo C002 H mm.NHm5.NH 50.HHN0.0 mH.Hflom.v Hv.NHm5.mH 00.NHN5.0 9400 0N.H000.0H N0.0000.0N Hm.HHmN.mH 00.HH50.0H H0.HHm5.NH ozma N0.Hn5m.vH Nm.HHN0.0H m5.0HNO.MH mm.0HNO.mH 00.NHN0.0H dez 00.HH5m.0H 05.0HNH.0H 00.0HN0.0H N0.0HmN.HH Nm.NHN5.5 omHz 00.HHmN.mH 00.Hwom.5H NH.N000.0H 0m.Hnom.0H 50.HHmN.mH wde 00.HHm5.0H 00.HHNH.0 00.H000.mH 0m.HHN0.0 00.HH50.0 45H: mm.HHN0.0H 00.HHNH.0H m0.0n5m.vH N0.Hum5.¢H N0.0HN0.0H name 00 0N v H x0030 wuHHmooa mnsom CH mEHB I .mHm>wH COHDHQHQEH usom #0 mmHuHHCOOH Cm>mm Comm ESSCHOUO .m CH Honum pumpCmum 0C0 COHHMCHEHmm H G002! I . HAN mam/5H. 130 131 TABLE A2.--Analysis of variance of mean germination in E. odoratum from seven localities at four soaking levels. Source df MS F Total 275 165.11 Subgroups 34 1098.68 32.89H Pops. 6 5191.09 155.40** Trts. 4 576.01 17.24** Pops. x Trts. 24 162.69 4.87** Error 241 33.40 ** Significant at P>0.01 level. 132 e~.mHH.mm ie.Hmvmm 10.0meem 10.5H00m Ce.meve~ Am.mmvo~ 9000 me.mse.me Ae.0eemm Ae.emvem 10.5500H 10.0000H Ae.Hmvem ozme mm.m0m.mm Am.emvom 10.5000m Am.emvmm 10.000em Am.~evma «CH2 He.m00.mm Am.HeemN Am.eevmm Am.~evmm 10.0000m 10.0mvom emHz mm.~00.mm ie.mmvem Ae.eeemH ie.0mva 10.0000N Ae.mmvem 0¢Hz mm.esm.0m ie.mevem im.mm0em le.mmvm~ 10.0mvmm 10.5memm «was am.HHe.e0 Am.emcmm 10.0mvmm Am.mmvmm 1e.mmvm~ 10.000em name 0000 0 we em 0 H x0000 NpHHmooC .0.0 new: musom CH mEHB .mHm>mH mCHxMOm usom um mmHuHHMOOH Cw>mm Eonm ECHMHOUO .m CH COHHMCHEHmm mmmvaonm UCm COHHMCHEHmm ESEmeE Commn 0H mmmp mo Hmnfidzll.mm mqmde l . . TABLE A4.-~Percentage germination and number of days to reach maximum germination in parenthesis in E. odoratum from seven localities at varied maLs-;w stress. Atmospheres Locality Check 1 3 5 8 10 THLD 48(25) 32(20) 12(25) 9(25) 0 MLYA 41(25) 27(25) 24(25) 21(20) 4(10) NIAG 61(15) 47(15) 43(15) 24(10) 15(15) NISO 41(15) 39(25) 30(20) 22(20) 2(10) GUAT 9(10) 9(10) 12(15) 4(15) 0 TRND 53(20) 55(15) 73(15) 68(15) 30(15) lMean of two reciplicates of50 seeds except TRND (40 seeds). TABLE A5.--Analysis of variance' of percentage germination arc sin transformation in E. odoratum from six 0 I O O — —-—————'—- localities at various m01sutre tenSions. Source df MS F Total 29 241.78 Treatments 4 669.46 3.861* Error 25 173.36 * Significant at P>0.05. 134 .00000 0N mo meumoHHmmn 0 mo C002 H .AN mHMHmV muoozm mo mOCMCMmmmm ecu pm peuuonm muoon .1 8H0.0H0.H mm.m#0.NH mv.0H5.0 00.0Hm.H 0N.¢H0.0H vo.mHN.MH BHm um mmHuHHMUOH C0>0m EOHH Esumnopo .m Houum pummCmum 0C0 COHHMCHEHmm H cmmzll.m¢ mqmda 135 TABLE A7.--Mean germination and standard error in E. 050:5? ~ from seven localities under light treatEhnt. Continuous Continuous llhrs L Cont. dark: Light dark 13hrs D Trt.Trfd . .. ..... TollL—13D THLD 6.0i1.29 0.5i0.29 10.3:0.75 13.010.91 MLYA 8.011.00 1.510.50 7.5i1.85 7.7i0.75 NIAG 15.2il.3l 10.0il.22 13.5i0.64 7.010.71 NISO 8.7i0.75 1.5i0.29 5.0:0.4l 8.0i0.82 NIFA 13.7il.31 3.5i1.l9 14.0i1.47 12.5i0.50 TRND 15.7i2.29 6.0i1.78 17.7i0.25 6.5il.85 GUAT 6.5i2.82 1.0i0.71 9.710.48 1.0i1.00 aTransfer made after the first twenty days. TABLE A8.--Mean1 E. 136 dry weight (g) at three sampling periods odoratum from seven localities. I .Y' J Populations Sampling Periods THLD MLYA NIAG NISO GUAT TRND FLRD C.L 1 5.74 3.20 6.10 7.57 12.16 3.41 5.28 1.15 2 5.79 5.06 6.82 8.37 14.66 3.96 4.74 1.38 3 8.80 4.80 9.80 10.30 20.85 3.57 3.67 2..8 Mean 6.77 4.35 7.57 8.74 15.89 3.64 4.56 1 59 1Mean of four replicates. TABLE A9.--Ana1ysis of variance of mean dry weight in E. odoratum from seven localities. H u Source df MS Fs Total 20 18.925 ** Populations 6 52.860 12.065 Error 14 4.381 * * Significant at P<0.01. 137 TABLE AlO..--Mean1 root/shoot ratio (x10) at three sampling periods in E. odoratum from seven localities E. odoratum—§ 10. Localities Sampling Periods THLD MLYA NIAG NISO GUAT TRND FLRD S . E . 1 6.51 3.97 6.44 6.92 4.48 3.64 5.80 0.51 2 7.08 4.46 5.97 7.31 4.44 2.77 2.94 0.69 3 6.84 5.48 4.00 5.15 3.33 3.47 1.79 0.52 Mean 6.81 4.64 5.47 6.46 4.08 3.29 3.40 0.53 1Mean of four replicates. TABLE E. odoratum from seven localities. All.--Ana1ysis of variance of mean root/shoot ratio in Source df MS Fs Total 20 20.421 ** Populations 6 79.111 32.807 Error 14 2.411 * * Significant at P<0.01. 138 TABLE A12.--Root weight ratio (RWR) and leaf area ratio (LA?) (cm /gm) of E. odoratum over three sampling periods from—Seven localities. Locality RWR LAR 1 2 . Mean . .l , 2 —Eean THLD 0.400 0.410 ’0.405 86.52 58.35 72.43 MLYA 0.302 0.304 0.303 125.14 101.52 1-3 : NIAG 0.382 0.325 0.353 68.68 69.31 63.9' NISO 0.423 0.347 0.385 64.86 65.44 65.15 GUAT 0.307 0.272 0.289 89.37 85.12 87.24 TRND 0.239 0.236 0.237 116.20 120.42 118.31 FLRD 0.287 0.232 0.259 106.80 124.60 115.70 139 .500 ee.mH-ee.eH Ame-eHez0eHom 00H0H03 500060505 0 0250 .500 eo.Humm.ozAwmmumev 50H00m0o 0H0Hm n .o.mm .500.eo.ezlwemuomv 0eHom 0000005000 u .e.mH mo.m 00.5 05.0 5m.m 55.0 00.0 50.0 000: mo.H om.H 00.0 mm.m 0m.H m~.Hu 00.0 00.5 m 05.0 00.0 00.0 em.0 mm.0 05.0 0H.o 00.5 5 035m 05.0 00.0 em.H om.0 00.0 om.m 00.0 eH.0 H OH.5 om.m 55.05 mm.HH e5.mH 50.0 m0.eH e002 0H.m 00.0 OH.0 05.55 mH.~H 00.0H 05.0 00.0H m 00.~ 00.5 00.0 oe.mm 05.0H om.NH 00.0 em.OH m .o.mm 00.5 00.5 00.5 0H.~m 0H.m om.HH oe.m em.0H H mm.m mm.m mm.5H mm.0 m5.0 00.0 00.0 000: om.~ 05.0 00.0 00.0H 05.0 eH.5 00.0 mm.HH m mo.~ 05.5 mm.m ee.mH ee.HH om.5 00.0 00.0 N .0.0H 50.H 05.0 05.5 om.0H 00.0 00.0 oH.H 00.0 H .m.m emHm 0205 5000 omHz 00Hz 05H: ages 000000 000500005 0CHHmemm .mHm>mH mHSpmHoE 00050 00 meHuHHmooH C0>mm Eoum EdumHowo .m we Amv quHm3 >HQI|.mH¢ mHm00 00505005 000m @0030 00 5000000000 cm>mm EOHM Esumnoco .m £0 00000 voonm\uoomIl.5H¢ mqmde 142 TABLE Al6.--Analysis of variance of root/shoot ratio in g. odoratum from seven localities at three soil moisture levels. Source df MS Vs Total 62 19.143 Groups 20 28.821 ' 1.982* Population 6 63.679 4.381** Treatment 2 78.437 5.396** Pops. x Trt. 12 3.124 0.215 Error 42 14.533 * Significant at P>0.05. ** Significant at P<0.01. 143 00000 0000003 500000508 I 5 50005050 00000 n .0.05 00000 0000000005 u .0.50 55.5 50.5 55.5 55.0 55.5 55.0 05.5 55.5 5552 55.5 55.5 50.5 55.0 55.0 50.0 50.5 05.0 5 5305 55.5 50.5 50.5 55.5 55.5 55.5 05.5 55.5 0 50.5 55.5 05.5 55.5 55.0 55.5 55.0 55.5 cam: 55.5 55.0 55.5 55.5 55.0 55.5 55.0 05.5 5 .0.55 55.5 05.5 50.5 55.5 55.0 05.5 55.5 55.0 0 55.5 50.0 05.5 55.5 05.0 55.5 55.0 50.5 0502 55.5 05.0 55.5 55.0 55.5 05.5 55.0 05.5 5 .m.50 05.5 05.0 50.0 50.5 55.0 55.0 55.0 50.5 0 .5.5 0550 5200 0555 0502 0002 5002 5550 05>00050 050005000 .500>00000 00000505 03w 00>0 500>00 00005005 00000 00 5000000000 00>05 5000 50000000 .0 00 00000 000003 0oomlu.50« 00009 00000505 144 TABLE A18.--Analysis of variance of root weight ratio x 10 :0 E. odoratum from seven localities at three soil moisture levels at three sampling periods. Source df MS Fs Total 41 2.226 F- - Groups 20 3.514 3.515H Populations 6 7.642 7.644** Treatments 2 10.227 10.229** Pops. x Trts. 12 0.332 0.332 Error 21 0.999 ** Significant at P<0.01. J45 uc00m mc00003 ammuomEmB n % E 0 mu0ommmu 00000 u .0.00 ucflom coflumuspmm n .m.m0 000.00 00.00 00.00 00.00 00.00 00.00 00.00 00.00 cam: 000.00 00.00 00.000 00.000 00.00 00.00 00.00 00.00 0 0390 000.00 00.00 00.00 00.0 00.00 00.00 00.00 00.0 0 000.00 00.000 00.000 00.00 00.00 00.00 00.000 00.00 c002 000.00 00.000 00.000 00.00 00.00 00.00 00.000 00.00 0 .o.m0 000.00 00.00 00.000 00.00 00.00 00.00 00.000 00.00 0 000.00 00.000 00.000 00.00 00.00 00.00 00.00 00.00 cam: 000.00 00.000 00.000 00.00 00.00 00.0 00.00 00.00 0 .0.00 000.00 00.000 00.00 00.00 00.00 00.00 00.00 00.00 0 .m.m omqm 0200 9400 0002 0002 0002 0000 000000 ucmaummne mam0mfimm .m0m>nmpc0 mc00mEMm .} m3» cam m0m>m0 musumflofi mmnnp um mm0u000000 cw>mm 500m Edumuoco .m CH AEm\NEov oflumn mwnm wmmqlu.00¢ mqmdB 146 TABLE A20.--Ana1ysis of variance of leaf area ratio in g, odoratum from seven localities at three soil mOisture levels at three sampling periods. -00- Source df MS Fs Total 41 2316.879 Groups 20 4209.440 8.182“* populations 6 10361.331 20.141 * Treatments 2 13143.368 25.549,M Pops. x Trts. 12 355.493 0.691 Error 21 514.440 * * Significant at P<0.01. 147 000.0 000.0 000.0 000.0 000.0 000.0 000.0 0002 000.0 000.0 000.0 000.0 000.0 000.0 000.0 0 pom\mu:00m 0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 0002 000.0 000.0 000.0 000.0 000.0 000.0 000.0 0 pom\00200m 0 000.0 000.0 000.0 000.0 000.0 000.0 000.0 0 0000 0200 0000 0002 0002 0002 0000 000000 00>00 0000000 mc00m80m 0000000000 .0000000 @000QEMMIOBu 00>o 000>00 0000000 if! 030 00 0000000000 cm>0m 8000 85000000 .m CH Amy 000003 >00 cmwzln.0N¢ mammB 148 mmm.o mvm.o 0mm.o nvm.o m0m.o mmv.o nom.o 000: m0m.o mm~.o 000.0 mmm.o 00N.o vom.o mwm.o m 0om\00c00m m wmv.o 000.0 0mn.o mmv.o 000.0 mm>.o mmm.o 0 m0m.o 000.0 mm0.o onm.o omm.o 000.0 000.0 0002 000.0 omm.o mmm.o m0m.o onm.o o0m.o 000.0 m 0om\00c00m m hmm.o mom.o mmv.o omm.o om0.o mnm.o 000.0 0 0000 020a 0000 0002 0002 0002 0000 000000 00>00 0000000 0:00mfi0m 00000000000 .0000000 00000800 m30 00>o 000>00 0000000 030 00 0000000000 00>00 5000 ED000000 .0 00000 000:0\0000 c00zuu.~m0 m0m0B AT MICIHIHWINIHISIITH! iWWNWIHIWIV 3 1293 03071 1844