FAC‘FGRS IN THE GROWTH OF AXILLARY SUBS IN CHRYSANTHEMUM MORIFOUUM Thesis for the Degree. of Ph. D. M¥CH!GAN STATE UNWERSITY HARRY W. KEPPELER 1967 “nib-fink “ in ME}? 7-, ,~o’ n". ”.9 . .. ,‘ - .. g 1...??- ? 4’ 3’ 3"" a; THasm _' -. -. '~ , .. ! .xfkiz'fili. 1:35? 115313 :- 5 *r ~ 3, \ ‘77“:xli'y “1‘ Wmvxm‘ This is to certify that the thesis entitled FACTORS 1N THE GROWTH OF AXILLARY BUDS IN CHRYSANTHEMUM MORIFOLIUM presented b9 Harry N. Keppeler has been accepted towards fulfillment of the requirements for Ph.D. degree in Horticulture / / / ,_- aaa/ zeal/12m Major professor Date /%‘Z " (/1 //6/7 0—169 ABSTRACT FACTORS IN THE GROWTH OF AXILLARY BUDS IN CHRYSANTHEMUM MORIFOLIUM by Harry W. Keppeler Nine cultivars of ghrysanthemum were used to study the environmental factors affecting the growth of axillary buds. Plants were usually pinched above the 10th node and were grown under long days (16 hr. photoperiod) during the experimental period. Increase in temperature increased bud elongation at the top three nodes of the plant. A similar effect was noted with the use of the red or far-red spectrum. Increase in light intensity initiated bud growth at the lower nodes. Removal of the lower five leaves did not enhance bud growth in relation to the control plants. Excising the top five leaves induced increased growth in lower axillary buds and decreased growth of upper buds. Decreasing the nutrient concentrations produced a decline in the number of buds initiating growth. This reduction in bud initiation proceeded in an acrOpetal direction. Calcium, magnesium, or potassium in decreased concentrations caused a growth decline similar to that experienced with decreasing concentrations Of all nutrients. With high soil nutrition, increased relative humidity induced elongation in the top three buds. There was no Harry w. Keppeler comparable effect in lower buds. Higher light intensity decreased growth in the upper buds and stimulated growth in the lower buds. With low soil nutrition, increased relative humidity increased growth in the top two buds. Selective excision of the of the upper five buds indi- cated nutrient rather than auxin control of bud growth. Severing of vascular tissue above a lower axillary bud induced growth in that bud. Indoleacetic acid (10‘2M) in lanolin placed on the tip of the pinched plant inhibited growth in one case, but did not inhibit growth in another. Indoleacetic acid (lo-2M), indolebutyric acid (10-3M), 2, A-dichlorophen- oxyacetic acid (10'2M) and N-l-naphthyl phthalamic acid (lo-2M) inhibited growth in lower axillary buds when placed in notches above these buds. No consistent pattern of growth stimulation occurred with any of the growth substances utilized. FACTORS IN THE GROWTH OF AXILLARY BUDS IN CHRYSANTHEMUM MORIFOLIUM By Harry W. Keppeler A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Horticulture 1967 6%723% S-lc'éfi ACKNOWLEDGMENTS To Dr. Lindstrom for time and effort consumed in being a reporter, a counselor, and above all, a friend. His help was most appreciated. To other members of the Department of Horticulture staff who imparted "words of wisdom" when asked and allowed me to "borrow" items of equipment or supplies. To the Michigan State Florists' Association for a grant of $AOO which made possible the work on light quality. To Yoder Bros., Inc. of Barberton, Ohio, who gener- ously furnished Chrysanthemum cuttings when required. i1 TABLE OF CONTENTS ACKNOWLEDGMENTS ... . . . . . . . . . . . . . . LIST OF TABLES . . . . . . . . . . . . . . . . LIST OF FIGURES . . . . . . .-. . . . . . INTRODUCTION . . . . . . . . . . . . . . REVIEW OP LITERATURE . . . . . . . . . . . . The direct action of auxin The The indirect action of auxin diversion of growth factors by auxin MATERIALS AND METHODS . . . . . . . . . . . . . Plant propagation and culture Data interpretation Growth chambers Nutrient solutions Growth substances Tissue removal Relative humidity regulation ‘Light measurements Statistical design RESULTS 0 O O O O 0 O O O O 0 0 O O O O O O O 0 Temperature responses Light intensity and quality Defoliation Nutritional responses Nutrition and light intensity interaction Tissue excision Growth substances DISCUSSION 0 o o o o o o o o o o o o o o o o 0 SUMMARY 0 o o o o ' o o o o o o o o~ o o o o o o o BIBLIOGRAPHY O O O O O O O O 0 O O 0 O 0‘ O O 0 APPENDIX 0 O O O O O O O O O O O O O O O 0 0 iii Page ii iv vi 13 17 53 59 6O 67 Table 1. l0. ll. 12. LIST OF TABLES Cultivar "Mermaid" severed at the internodes and each node with leaf attached propa- gated in sand under intermittent mist for 50 days . . . . . . . . . . . . . . . . . Cultivar "Red Star" grown under two green- house temperatures for 26 days . . . . . . . Cultivar "Mermaid" exposed to short days and two light intensities for 3“ days . . . . . . Data analysis for Figure 9 . . . . . . . . . . Cultivar "Red Star" grown in nutrient solu— tions for 30 days . . . . . . . . . . . . . . Cultivar "Winter Carnival" grown in nutrient solutions for 18 days . . . . . . . . . . . . Cultivar "Red Star" grown in nutrient solutions for 35 days under two light intensities and three nutrient concentrations . . . . . . Cultivar "Bright Golden Anne" grown under two relative humidities and four light intensities for 21 days . . . . . . . . . . . Cultivar "Bright Golden Anne" grown under two relative humidities and four light inten- sities for 21 days . . . . . . . . . . . . . Cultivar "Winter Carnival" grown for 20 days with buds excised as indicated . . . . . . . Cultivar "Red Star" notched above buds 3, 5, and 7 and grown for 19 days . . . . . . . . Cultivar "Red Star" placed on subirrigation bench filled with sand and grown in a hori— zontal or upright position for 25 days. . . . iv Page 18 18 22 31 33 3A 36 38 40 U1 “3 “3 Table Page 13. Cultivar "Mermaid" placed on a subirrigation bench filled with sand and grown in a hori- zontal or upright position for 25 days . . . . NA 1“. Cultivar "Red Star" treated with IAA—lanolin paste placed on the tip of the pinched plant and grown for 16 days . . . .‘. . . .-. . M5 15. Cultivar "Mermaid" treated on pinch date and twice at A-day intervals and grown for 20 days 0 C O O O O O O O O O O C O O O O O O . 146 16. Cultivar "Bright Golden Anne" treated with lanolin-chemical paste placed on the tip of _ the pinched plant and grown for 20 days . . . . “7 17. Cultivar "Bright Golden Anne" notched above buds.6, 8, and 10. Lanolin-chemical paste placed in notches and plants grown for 20 days . . . . . . . . . . . . . . . . . . . . “9 V 18. Cultivar "Winter Carnival" notched above buds 7, 9, and 11. Lanolin-chemical paste placed in notches and plants grown for 14 days . . . . 50 19. Cultivar "Bright Golden Anne" treated with lanolin-chemical paste placed on the tip of the pinched plant and plants grown for 20 days . . . . . . . . . . . . . . .-. . . . . 51 20. Cultivar "Bright Golden Anne" notched above buds 6, 8 and 10. Lanolin-chemical paste placed in notches and plants grown for 20 days . . . . . . . . . .-. . . . . . . . . . 52 1A. Cultivar "Bronze Princess Anne" exposed to variable daylength for 26 days . . . . . . . . 68 2A. Cultivar "Hurricane" treated on pinch date and twice at 5 day intervals, and grown for 25 days 0 O O O O O O O O O O O O O C O O O O O O 69 3A. Cultivar "Orchid Quaflfl'treated by spraying and grown for 20 days . . . . . . . . . . . . . 70 AA. Cultivar "Mermaid" treated by spraying at pinch and twice at 3 day intervals, and grown for 20 days . . . . . . . . . . . . . . . 71 LIST OF FIGURES Figure Page 1. Cultivar "Starburst" grown for 21 days at two light intensities and two temperature regimes . . . . . . . . . . . . . . . . . . . . 19 2. Cultivar "Mermaid" grown at two light intensities for 25 days . . . . . . . . . . . . 21 3. Cultivar "Mermaid" grown under 14 hr. and 20 hr. photoperiod for 20 days . . . . . . . . 2A A. Cultivar "Winter Carnival" grown under two spectra for 21 days . . . . . . . . . . . . . . 25 5. Cultivar "Starburst" grown under two spectra for 214 days 0 O O O O O O O O O O O 0 O O O O O 26 6.7 Cultivar "Bright Golden Anne" grown under two spectra for 18 days . . . . . . . . . . . . 27 7. Cultivar "Mermaid" grown under two spectra for 21 days 0 0 O O O O O O O O 0 O O O O O O O 28 8. Cultivar "Winter Carnival" partially or fully defoliated and grown for 21 days . . . . . . . 3O 9. Cultivar "Mermaid" grown for 23 days with leaves removed as indicated . . . . . . . . . . 31 10. Cultivar "Winter Carnival" grown in nutrient solutions for 19 days . . . . . . . . . . . . . 32 ll. Cultivar "Mermaid" grown under intermittent mist and non-mist conditions for 21 days . . . 37 1A. Typical light spectrum as recorded in a green- house at noon on a bright day in August . . . . 72 2A. Light spectrum resulting from the use of cool white fluorescent tubes with a blue Rohm and Haas (#2A2A) filter . . . . . . . . . . . . 73 3A. Light spectrum resulting from the use of cool white fluorescent tubes with a red Rohm and Haas (#2u23) filter . . . . . . . . . . . . . . 7“ vi Figure Page AA. Light spectrum resulting from the use of cool white fluorescent tubes with the addition of incandescent flood bulbs filtered by a FR 700 filter . . . . . . . . . . . . . . . .- 75 5A. Light spectrum using cool white fluorescent tubes as the main source with the addition of two 25W incandescent sources . . . . . . . . 76 6A. Light spectrum resulting from two layers of red cellophane (Dennison) as a filter and using cool white fluorescent tubes as the main light source . . . . . . . . . . . . . 77 7A. Light spectrum resulting from two layers of blue cellophane (Dennison) as a filter and using cool white fluorescent tubes as the main light source . . . . . . . . . . . 78 vii INTRODUCTION Apical dominance in Chrysanthemum morifolium has a wide range of expression. In many cultivars, few lateral branches develop after the terminal bud is removed while in others, more occur. The variation may be illustrated by the cultivars "Mermaid" and "Princess Anne." "Mermaid" will produce five to six lateral branches after terminal bud removal; "Princess Anne" three to four. These lateral branches arise from buds immediately below the point of terminal bud detachment. This variation in apical dominance is noted through- out the plant world. One extreme form occurs in genera such as Philodendron where destruction of the terminal bud results in the growth of the next closest axillary bud. In general, only one axillary bud will grow. An opposite extreme form is found in Coleus where the terminal bud exhibits little apical dominance. In this study, certain environmental factors involved in axillary bud growth have been investigated. Because of the vast research in the theoretical phyto—hormonal mechanism area, a considerable amount of time was spent investigating other environmental factors which might influence the growth of axillary buds. Simultaneously, an attempt would be made to correlate the phyto—hormonal system with these factors. REVIEW OF LITERATURE Apical dominance is defined by some authors as "correlative inhibition" and.isexplained as the inhibition of axillary bud growth by the terminal bud. When the terminal bud is destroyed, the development of the upper axillary buds induces inhibition of lower buds. 'This theory is recognized in this paper. Theoretically, all axillary buds are released from inhibition at the moment of terminal bud destruction. A number of axillaries start growth during this non-inhibi— tive period. The re-establishment of inhibition by the topmost axillaries limits the number which continue growth. Apical dominance has long been under investigation. Two early theories suggested either an internal hormone as the correlating agent or a nutritional explanation. In 1925, Snow (51) demonstrated an internal hormone's existence. The development by Went (6A) of the Azena test in 1928 enabled Kdgl and Haagen-Smit (29) to isolate and purify auxin "A" from human urine. Later auxin "B" was isolated and purified from plant sources. Eventually, "heteroauxin" was isolated and purified from urine and was identified as B-indoleacetic acid. Later, Haagen-Smit 23 31. (21,22) isolated B-indoleacetic acid in pure form from corn meal and corn germ. This work and other confirming data suggested that indoleacetic acid is the most important growth hormone in plants. Apical dominance is usually mentioned with reference to auxin.a Thimann's (60) review in 1939 stated nine different mechanisms which might account for the inhibition. In 1956, Allsopp (1) summarized the nine mechanisms into three distinct theories: (a) auxin acts directly as an inhibitor of axillary buds; (b) auxin produces some process which gives rise to a special inhibiting influence; (0) auxin leads to a diversion of nutrients or growth factors. Investigators (19, 57) have found the terminal bud rich in auxin; others (12, 50, 52, 58) discovered more in the young leaves. In a few cases (19, 62) the extending internodes of the stem have yielded more auxin than either the terminal bud or the young leaves. Basipetal movement of auxin has been demonstrated. Le Fanu (35) observed that auxin-lanolin paste inhibited or stimulated growth of young internodes. The inhibition or stimulation depended upon the placement of the paste below or above the tissue involved. She concluded that there was more basipetal transport than acropetal transport. This aThe terms auxin and IAA will both refer to B-indole- acetic acid unless otherwise specified. conclusion has been verified (2A, 3A, 37, 39, 40, Al, 53, 5A, 66, 70). Wickson and Thimann (7) found that apical sections of Pisgm stem transported more auxin than did older stem sections. Movement was largely basipetal and was reduced by conditions that favored axillary bud growth. McCready and Jacobs (39) verified this decline of basipetal movement with age. They associated it with a steady increase in acropetal auxin movement and with a progressive decrease in *rthe ability of the sections to grow in length. Leopold and Guernsey (37) illustrated a changing ratio of basipetal/ acropetal transport from a vegetative stem tip to a flowering stem tip. This occurred although basipetal transport decreased with stem age. McCready and Jacobs (“1) indicated that the mechanism of transport may be different for the two directions involved. However, the data of Le Fanu (35) showed little auxin transport in either direction in a com- pletely inhibited shoot of Pisum. Thimann (59) was one of the first investigators to illustrate the control of axillary bud growth by auxin synthesis and transport. He applied auxin to either the‘ stem above the axillary buds or directly to the axillary buds of Pisum seedlings. This resulted in an equal inhib- itory effect on the growth of the axillary buds. Delisle (12) showed that auxin applied to the cut ends of Aster leaves inhibited axillary bud growth. Other investigators (17, 25, 3A, 36, 50, 62, 63, 66) have since confirmed this general reaction although the effectiveness of the inhi- bition varies greatly among species. To resolve the direct auxin theory, many (25, A7, 58, 63, 70) have shown an increase in auxin content of axillary buds following terminal bud destruction. Others (50, 63) pointed out a corresponding decrease of auxin in the stem tissue. Wickson and Thimann (7) also found a linear relationship between the inhibition re-established by upper axillary buds and the content of externally applied IAA isotope in the axillary bud tissue of Pigum. They concluded that auxin produced in the terminal bud, leaves, or stem did reach the axillary buds. Snow (53) and Went (66) favored Allsopp's (1) second theory and pointed out the phenomenon of increasing inhibition with increasing distance. This conclusion was disputed by Thimann (59). Van Overbeek (63) found that the longer the time lapse between decapitation and application of external auxin, the less effective was the inhibition of axillary bud growth. Gordon (17), working with x-ray irradiation, showed an inconsistency in the time relationship. He found that irradiation of the terminal tip of Xanthium would cause subjacent axillaries to grow. In addition, external auxin applied to the irradiated terminal tip for two days caused postponement of axillary bud growth for two days. However, external auxin application for two weeks following irradiation caused axillary buds to remain dormant. Auxin application had suppressed their growth during the two weeks. Jacobs 33 al. (25) showed that 1% IAA in lanolin had no inhibiting effect on the growth of axillary buds. This amount of IAA exactly substitutes for the terminal tip in providing auxin through the second node from the apex. They had previously demonstrated apical dominance in a clone of Coleus blumei. Smith (50) and Snow (51) found inhibition interrupted by physiological shock (steam). Snow (51) illustrated inconsistencies in inhibition interruption by severing different tissues individually (xylem, phloem, pith). Severance of the phloem did not interrupt inhi- bition, but severance of both xylem and phloem did. Main- taining connections between axillary bud and main apex by only the xylem did not interrupt inhibition. Snow (55) stated an indirect theory (1) in the following manner: auxin travels down the stem from the growing apex or leaves. The primary positive effect of auxin overrides the secondary inhibiting influence. Very little auxin travels acropetally into a lateral bud or shoot. The inhibiting influence moves upward and produces its effect. Went (65) postulated the presence of hormone- like factors (calines). These are formed in the roots and are required for the elongation of the stem or axillary buds. He also stated that auxin causes a redistribution of calines in the plant. Kefford (27) apparently confirmed these theories by chromotographic separation of growth substances. Using etiolated bean shoots, he found IAA the predominating growth substance in the stem. Inhibitor B predominated in the first axillary bud. Many chemical substances (5, 11, A7, 69) overcome auxin inhibition of axillary bud growth. Audus (5) stated that high concentrations of adenine would accomplish this purpose. Wickson and Thimann (69) reported the removal of auxin inhibition on isolated Pisum stem sections by kinetin, an adenine derivative. However, Davies 32 a1. (11) showed an increase of auxin inhibition on axillary bud growth in bean by kinetin. Both Wickson and Thimann (69) and Sachs and Thimann (A7) illustrated with Pisum that kinetin released axillary buds from inhibition by the intact apex. Buds released would not elongate as much as uninhibited buds. The bud would react normally with an auxin treat- ment. They (A7) suggested that growing shoots are rela- tively insensitive to correlative inhibition because they synthesize two types of growth substances. A possible partial explanation for the auxin-kinetin interaction was shown by Seth et a1. (48) and Davies gt 31. (ll). IAA promoted kinetin transport and kinetin promoted IAA tranSport. Other substances have been shown to affect auxin transport. Niedergang-Kamien and Leopold (A3) reported that dinitrophenol (a classical respiration inhibitor) inhibited auxin transport at concentrations which stimulated respiration. They also reported transport inhibition by TIBA (2, 3, 5-Triiodobenzoic acid). Hay (23) found trans- port inhibition with 2, A-D (2,A-DichlorOphenoxyacetic acid) and TIBA. Jacobs (26) showed increased auxin transport with gibberellic acid. As a possible consequence of this auxin transport interaction, Asen and Hamner (3) found TIBA to be the most effective inductor of basal shoots on rose plants. However, regardless of the chemical used, 60% of the total number of basal shoots developing were on the outside rows. Brian SE‘El' (9) have shown that gibberellic acid enhances apical dominance in the self-branching "Cupid" sweet peas. Wickson and Thimann (69) found that gibberellic acid promoted bud elongation and occurs only after inhibition has been released. Other chemicals (7, 36, 38, 39) have been reported as affecting some phase of apical dominance. Leopold (36) observed the effect of auxin (Naphthaleneacetic acid) in reducing tillering in barley, while TIBA was effective in increasing it. Beach and Leopold (7) reported that maleic hydrazide broke apical dominance in Chrysanthemum. Mitchell 22 a1. (39) showed the varying response of 6A phthalamic acids in controlling apical dominance. Libbert (38) found that NMSP (d-l-Naphthylmethylsulfide propionic acid) stimulated uninhibited axillary buds of Pigum. It also stimulated correlatively inhibited buds. The above summary is conflicting and inconclusive. The third theory (1), the nutrient theory, can be divided into two general sections: light effects and inorganic nutrition. Plant growth can be influenced by light quality or light intensity. The effects of light quality and light intensity have been difficult to separate. Went (67) experimented with Pigum seedlings and found growth in length decreasing with small amounts of red light. Increasing intensity of light was more effective in decreasing the length than increasing duration. He suggested a dual effect of red light: (a) it caused excessive growth (red etiolation); (b) it decreased growth in length compared to dark etiolation. This conclu- sion has been supported by Dunn and Went (13) with utili- zation of the yellow region of the spectrum or increased amounts of incandescent light which is high in red and infra-red wave lengths. Arthur and Stewart (2) and Withrow Land Withrow (71) also confirmed the dual effect with incan- descent or other light sources having high proportions of infra-red. There has been an attempt to correlate these results with growth substances. Thimann and Skoog (58) stated that the production of growth substance takes place only in light. However, he established no thresholds, nor did it 10 appear that there was a linear relationship between the two factors. Red and blue-violet light produced approxi- mately the same amounts of growth substance, while far-red and yellow-green produced less. Thimann and Wardlaw (61) observed the accumulation of IAA under high light intensity which induced elongation. This was observed with both red and blue light. In contrast, Galston and Hand (15) found that, at any given auxin level, white light decreased the amount of growth produced. This was not due to differences in auxin content, but to a light-induced differential response to auxin. There has been agreement in the few reports on the interaction of auxin and nutrient uptake, translocation and accumulation. Auxin enhanced the uptake of salt and water in potato slices (10) and was capable of preventing plasmolysis in hypertonic sucrose solutions. When applied to the third or fourth mature leaf from the apex, sucrose (1A0) moved in an acropetal direction (8). This movement was enhanced in plants with terminal bud intact or With IAA-lanolin paste substituted. There was less movement in plants with the terminal bud detached. Zaerr (72) found a direct correlation of IAA transport with the degree of sucrose (luC) accumulation in the morphological base of stem sections. Some authors (13, 33, AA) believed there was a direct correlation between increasing light intensity and plant 11 growth as measured by dry weight increase. There was disagreement as to which wave lengths of light are most efficient in dry weight production. Dunn and Went (13) found red wave lengths more effective. Rohrbaugh (A6) observed nearly equal production in the red and blue regions. Shirley (A9) showed the blue-violet region to be more efficient at low intensities and observed that the complete solar spectrum was more efficient per unit light intensity than any one portion of it. As to inorganic nutrition, Kraus (31) outlined its relationship to organic nutrition and resulting vegetative growth. Gunckel 33 a1. (20) suggested that the ability of long shoots to develop from uninhibited lateral buds in Gingko was a function of general nutrition. Gregory and Veale (18) concluded that the main factor in apical dominance in flax was nutrition. They thought it was not. an inhibitor which induced less activity in buds but rather a competitive effect for a limited nutrient supply. Flax exhibits little apical dominance. An increase or decrease in the tillering of barley was controlled largely by nutrient supply (A). Goodwin and Cansfield (26) found nutrient supply not directly involved in inhibition of lateral buds on potato tubers, but high nutrient supply could partially offset the effect of the inhibitor. l2 Klebs (28) investigated interactions of light and nutrient factors. He found that the absolute values of several factors (light intensity, temperature, soil nutrients) were of little value. However, the relation- ship between factors was of consequence in the develop— ment of Sempervivum. Kwack and Dunn (32) observed no differences in dry weight of pods with Pisum grown under equal intensities with three different nutrient levels. The levels were all of high order (0.5x, 1X, 2X). In another experiment with equal light intensities, length of photoperiod caused marked differences in yields. One example in the applied area was reported by Post (A5) who found differences in branching with inter- actions between last pinch and start of short days. However, this involved the complications of the flowering apex. White (68) and Fries and White (1A) have investi- gated branching differences obtained with changing watering frequencies and constant feed procedures. Tayama and Kiplinger (56) observed an effect of light intensity, caused by planting different numbers of Chrysanthemum cuttings in the same size pot. Kohl and Nelson (30) confirmed this effect (56) and showed differences from environmental factors which vary from month to month. MATERIALS AND METHODS Nine cultivars of Chrysanthemum morifolium used in this study were obtained as rooted cuttings from a commer- cial propagator or cuttingsvmnxepropagated from stock plants grown in a greenhouse at Michigan State University. Stock plants and cuttings were grown at 60 F night temper- ature and under long photoperiods (1A hrs. or 16 hrs). Each rooted cutting was placed in a A" clay pot in a soil consisting of equal parts of a clay-loam, peat moss, and a soil conditioner ("Turface" or perlite). Plants were usually severed at a height of ten nodes from the soil surface; however, several variations in heights were used. The plant height is indicated in the tables and figures by the number of nodes at which measure- ments were taken. The node numbering system used in the tables and figures starts at the point in an internode where the ter- minal tip of the plant was removed and proceeds in a basi- petal direction to the soil surface. The point of terminal tip detachment is considered as the tOp of the plant. Axillary buds are numbered by the same method. Growth chambers were used for some experiments. Temper- atures utilized were 60 F night and 70 F day unless otherwise -..... l3 1A specified. The growth chambers contain a clear plastic barrier between the lights and the growing chamber. Controlled environmental light quality work was done by substituting a colored filter for the plastic barrier. In one experiment, colored cellOphane was added to the plastic barrier. In addition, two "growth chamber" boxes were con- structed with approximate dimensions of 28" x A2" x 30". Fluorescent and incandescent lights were installed and an exhaust fan pulled air through the chamber. These boxes were placed in a thermostatically temperature controlled room. Nutrient solutions (modified Hoaglanda) for the nutritional levels experiments were formulated at the 1.0 X level as follows: Ca(NO3)2 -- 1M - 15 ml per gal. solution KNO3 -- 1M - 15 ml per gal. solution MgSOu -— 1M - 8 ml per gal. solution NaH2POu —- 1M - A ml per gal. solution FeNa EDTA -- 0.1M - A ml per gal. solution H3BOs -- 0.0AM - A ml per gal. solution MnCl2 -- 0.008M - A ml per gal. solution ZnCl2 -- 0.0008M - A ml per gal. solution CuCl2 -- 0.0003M — A ml per gal. solution MoO3 -- 0.0003M - A ml per gal. solution aHoagland, D. R. and W. C. Snyder, 1933 Proc. Amer. Soc. Hort. Sci. 30:288-29A. 15 Plants were grown in gallon Jars with constant aeration. Distilled water was added to replace that lost by trans- piration and evaporation. Plants were placed in fresh solutions every fifteen days. Growth substances applied as sprays were dissolved in small amounts of 50% ethanol and diluted to the indicated concentrations with 50% ethanol. Substances were sprayed on leaves with a small, plastic, manually—operated sprayer. Spray was applied till run-off occurred. In some experi- ments plant leaves were immersed in the solutions for ten seconds. Growth substances utilized were indoleacetic acid, gibberellic acid, indolebutyric acid, kinetin, and N6 benzyl adenine. Growth substances for lanolin application experi- ments were added to lanolin as crystalline material. Where lower concentrations were used, the substances were dis- solved in small amounts of 50% ethanol and diluted to the proper concentration before addition to lanolin. Lanolin was melted in a hot water (60 C) bath for proper mixing. Growth substances used were indoleacetic acid, N6-benzyl- adenine, B995, thioracil, gibberellic acid, 2,A—dichloro- anisole, AmChem #67-109, AmChem #66-329, 2,3,5-triiodo- benzoic acid, 2,A-dinitrophenol, Alanap, 2,A-dichloro— phenoxyacetic acid, and dichloropropionic acid. The "notching" technique was accomplished by severing the vascular tissue at an internode. The notch was always 16 directly above an axillary bud and approximately 1/2" from it. Leaves were removed from the plant by severing the petiole not more than l/A" from the stem. Axillary buds were excised with a small knife with no damage to other tissues. Intermittent mist was regulated by the use of an artificial leaf. Relative humidity was increased with the use of a mist tent. Small areas of a propagation bench were enclosed with polyethylene plastic. A mist nozzle inside the tent (regulated by an artificial leaf) pro- vided additional moisture. A 6" space was left open at the bottom of the tent on two sides. This space provided air circulation and partial temperature regulation. Light energy was automatically recorded with an ISCOa Spectraradiometer and energy computations were made with polar planimeter measurements of the chart area. A completely randomized statistical design was used. An analysis of variance table was computed for bud growth at each node. Experiments with more than two treatments required the use of orthogonal or non-orthogonal compari- sons. Five Inillimeters was the shortest measurement observed and indicated a range from no visible elongation to a measurement of five millimeters. aInstrumentation Specialities Co., Lincoln, Nebr. RESULTS To determine the capacity for growth of the various axillary buds on the stem of the Chrysanthemum, the plant was severed between nodes and the node plus leaf was placed in a sand bench under intermittent mist. The growth of the axillary buds of a plant with 10 nodes was determined (Table 1). Several of the basal buds elongated as much or more than the upper buds. Plants were grown at different temperatures to deter- mine the temperature effect on axillary bud growth. A temperature increase from 50 F to 65 F increased growth; however, this increase was in the first three buds from the tOp (Table 2). In the interaction of temperature and light intensity, temperature stimulation is also illus- trated (Figure l). A combination of high night temperature (80 F) and a low light intensity (109,080 micro-watts/cm2) produced similar growth when compared with a higher light intensity (359,900 micro-watts/cm2) and lower night temper- atures (started at 75 F, changed to 60 F after 7 days). Growth initiated by high temperature stimulation occurred at the top three nodes while buds at nodes A through 10 showed increased growth with the higher intensity-lower night temperature treatment. 17 18 TABLE l.--Cultivar "Mermaid" severed at the internodes, and each node with leaf attached propagated in sand under intermittent mist for 50 days. Node from top of plant l 2 3 A 5 6 7 8 9 10 Mean growth of axillary buds l9 l2 17 25 22 18 12 2A 28 ‘AO _-}§_TT; ________________________________________________ Non-orthogonalf a a a a a a a a a b comparison a a a a b F test. a a b a a a b a b a f Within a line, mean (8 plants) designated by (a) are significantly different from means designated by (b) at the 5% level. TABLE 2.—-Cultivar "Red Star" grown under two greenhouse temperatures for 26 days. Mean axillary bud growth in mm. Treatment Node from top of plant 1 2 3 A 5 ' 6 7 8 Temperature 65 F 116a 108a 103a 28a 10a éa 5a 3a Temperature b 50 F 72 aMeans (8 plants) within a column followed by different letters are significantly different at the 5% level by the F test. l9 -———- 0 75F,60F Night Temp. 80 High intensity f: ---- X 80F Night Temp. 5 Low intensity V so .c U § on 4C) .g \\ O-_ .o \\ 5 2° at- g *~~—x.-1 O 'X“"'7X l' 2 3 4 5 6 7 8 9 l() Node from t0p of plant Figure l - Cultivar 'Starburst' grown for 2l days at two l'ght inten- sities (359,900 micro-watts/cm2 vs. 109,080 micro-watts/cm ). Plants under high intensity light started at 75 F night temperature and changed to 60 F after 7 days. The mean growth (IO plants) of the axillary buds at nodes A through IO significantly different at the 5% level by the F test. 20 With the same night temperature (60 F) but two light intensities (109,080 micro-watts/cm2 vs. 359,900 micro- watts/cm2), significant differences in growth were noted only at nodes A, 6, and 7 (Figure 2). This response was under long photoperiod (16 hrs.) (vegetative growth). Using the same cultivar and environmental conditions except for short photoperiods (8 hrs.) (reproductive growth), significant growth increases occurred at every node with high light intensity (Table 3). The growth pattern was changed under high light intensity. In this situation, the growth differences were less between upper and basal buds which was a variation from the usual apical to basal growth decline illustrated by low inten- sity. In another experiment with plants grown in the greenhouse in October, there were no significant differ- ences in growth between plants grown under long days (16 hrs.) and short days (8 hrs.) (Table 1A, Appendix). With an additional increase in photoperiod (1A hrs. vs. 20 hrs.) under high light intensity (359,900 micro-watts/cm2) and a 60 F night temperature, growth increases were obtained at nodes 5 and 8 with the longer photoperiod. The growth increases obtained with increases in light intensity indicated that experiments with light quality might yield positive information. With differences in light intensity (red spectrum-18JEM)micro-watts/cm2; blue spectrum-12,320 micro-watts/cm2), the red spectrum 21 I4C) -———- 0 Int. 3592900 micro- X“t . watts/cm IZO X\ -..-.. X Int. 109é080 micro- A \\ watts/cm ' l j; QC) .2 E 80 O a. ‘3 so .0 C'. (U :2 40 2C) 0 I 2 3 4 5 6 7 8 9 IO Node from tOp of plant Figure 2 - Cultivar 'Mermaid' grown at two light intensities for 25 days. The mean growth (6 plants) of the axillary buds at nodes A, 6, and 7 significantly different at the 5% level by the F test. 22 TABLE 3.--Cultivar "Mermaid" exposed to short days (8 hr. photoperiods) and two light intensities (359 900 micro- watts/cm2 vs. 109,080 micro-watts/cm2) for 3A days. Mean axillary bud growth in mm. Treatment Node from top of plant 1 2 3 A 5 6 7 8 9 10 High intensity 156a 160a 15Aa 1A2a llAa 75a 5A3 658 98a 89a b b b b b b Low intensity 82b 87b 79b 3Ab 30 10 9 9 9 9 aMeans (6 plants) within a column followed by differ- ent letters are significantly different at the 5% level by the F test. 23 increased growth at nodes 3 and A (Figure A). However, with the blue spectrum, decreasing growth from node 1 through node 3 did not follow the usual curve (lesser differences in growth) for plants grown under white light. This curve was better illustrated by growth under the red spectrum. The use of red and blue spectra of higher in- tensities (32,100 micro-watts/cm2 vs. 76,000 micro—watts/cm2 respectively) obtained growth curves illustrated in Figure 5. Higher intensity of the blue spectrum produced more growth at every node with a different cultivar. The composition of the blue spectrum included other areas of the spectrum (Figure 7A, Appendix). The use of two spectra which differed only in the infra-red (188, 350 micro-watts/cm2 vs. 1350 micro- watts/cme) produced two different growth curves (Figure 6). The use of the infra-red spectrum induced excessive elong- ation at the tOp three nodes although there was less growth at nodes 7, 8, and 9. Excessive growth was noted again at the top three nodes with the use of a red spectrum (Figure 7). Spectrum, light intensity, and environmental factors were identical as with the plants treated in an earlier experiment (Figure A) although another cultivar was used. In an attempt to designate a particular portion of the plant as the initiator of growth stimulation or inhibition by light, two defoliation experiments were used. The two 2A lZO H30 80 6C> 4C) Mean bud growth (mm.) "-—- 0 20 Hr. Photoperiod 2C) ---- X 14 Hr. Photoperiod 12 3 4 5 6 7,8 910 Node from tOp of plant Figure 3 ' Cultivar 'Mermaid' grown under lA hr. and 20 hr. photo- period for 20 days. The mean growth (l0 plants) of the axillary buds at nodes 5 and 8 significantly differert at the 5% level by the F test. .25 -—-—— 0 Red 4sgectrum: intensitg micro-watts/ cm ---- X Blue spectrum: intensity 12,520 micro-watts/cm2 Mean bud growth (mm.) \ . O A X‘~~—-:::-W l .2 3 4 5 6 7 8 9 IO Node from top of plant Figure A - Cultivar 'Winter Carnival' grown under two spectra for 2| days. Red spectrum (Figure 3A - Appendix); blue spectrum (Figure 2A - Appendix). The mean growth (8 plants) of axillary buds at nodes 3 and A significantly different at the 5% level by the F test. 8C) 2' '5 S g 40 “U :3 D c 20 f0 0) Z 0 --- 0 Blue spectrum Int. 76,000 micro-watts/cm? ---- X Red spectrum. Int. 32,100 micro-watts/cm2 W—\\ X X \‘xt \\ \ \\\ X \\x 2 3 4 5 Node from top of plant Figure 5 - Cultivar 'Stardust' grown under two Spectra for 2A days. Red spectrum (Figure 6A - Appendix); blue spectrum (Figure 7A - Appendix). The mean growth (l0 plants) of the axillary buds at nodes l and 3 through l0 significantly different at the 5%.level by the F test. 27 VAO ___ ---— O (-) Far red:intensity 2 [20(7- XI‘x 105,110 micro-watts/cm ‘%\ ---- X-(+0 Far redzintensity A. \\ 295,950 micro-watts/cm2 ' IOC) E, \ .c \ g 8C) \ O 5‘ \ ‘U 60 s \\ x S \\ ,0; 4o 6 Q\ 20 O l 2 _ 3 4 5 Node from tOp of plant Figure 6 - Cultivar 'Bright Golden Anne' grown under two spectra for l8 days. (+) far red (Figure AA - Appendix); (-) Far Red (Figure 5A - Appendix). The mean growth (8 plants) of axillary buds at nodes l, 2, 3, 7, 8, and 9 significantly different at the 5% level by the F test. 28 ICC) kI—ux-t‘ --— 0 White spectrum ,I ‘ ' Int. 64,500 micro- é 80 "K\ watts/cm? : \ ---- X Red spectrum g 60 ‘ \ Int. 17,450 micro- 8 \ watts/cm? m '3 440 .D C m g 20 \ . '-o"x o 7'6" T44 o l 2 3 4 5 6 7 8 _9 IO Node from t0p of plant Figure 7 - Cultivar 'Mermaid' grown under two spectra for 2| days. Red spectrum (Figure 3A - Appendix); White spectrum (Figure 5A - Appendix). The mean growth (l0 plants) of axillary buds at nodes 1, 2, and 3 significantly different at the 5% level by the F test. 29 treatments of the first experiment restricted growth to the topmost five buds (Figure 8). Retaining the upper five leaves produced more growth in the top three buds with a steep decline in growth in buds A and 5. Growth was similar in buds 1 through 5 when all leaves were removed. Removal of the upper five leaves obtained comparable growth of axillary buds at 10 nodes (Figure 9). With a different cultivar, the growth curve--in comparison to the curve in Figure 8--was modified (less growth in buds 1 through 3, more growth in buds 6 through 9) when the lower five leaves were removed. Investigations in the applied area (1A, 68) have indicated nutrient influence in this problem. Using a 0.5X modified Hoagland solution induced differences in bud growth at nodes 2 and 3 (Figure 10). Use of 0.2X, 0.1X, and 0.05X solutions produced a corresponding decline in bud growth (Table 5). Buds at nodes 1 through 5 elongated when a 1.0X modified Hoagland was used; bud growth at the same node number declined progressively with decreasing concentration of the nutrient solution. At the 0.05X concentration, only buds l and 2 elongated. Trial experiments attributed this growth decline to more than one element. Of the key elements tested, cal- cium and potassium decreased growth at nodes 1 through 5 (Table 6). Zinc, copper, and magnesium showed no signif- icant growth decline until the fifth node. 3O /x\ I40 / \ / \X —-—- 0 All leaves .20 \ ---- X LowermOst five leaves \ \ H30 \ Mean bud growth (mm.) Node from tOp of plant Figure 8 - Cultivar 'Winter Carnival' partially or fully defoliated and grown for 2] days. The mean growth (5 plants) of the axillary buds at nodes 1, 2, and 3 significantly different at the 5% level by the F test. 31 '00 -———-0 Control -.-. X Lowermost five g 80 ---- Z Uppermost five 5 a,”2""2 3 5° ’3 0 CD g 40 O 6 .D \- O ‘— o/.~A C \.\ x o/./ 9 § 20 "‘/ x‘ O I 2 3 4 5 6 7 8 9 Node from t0p of plant Figure 9 - Cultivar 'Mermaid' grown for 23 days with leaves removed as indicated. TABLE A.—-Data analysis for Figure 9. Orthogonal Node from apex Comparison 1 2 3 A 5 6 7 8 9. Control vs lower 5 and upper 5 * * * NS NS NS NS NS NS Lower 5 vs upper 5 * * * NS NS NS NS NS NS *Means (6 plants) differ significantly within a column at the 5% level by the F test. 32 I20 --—--0 X concentration ---- X 0.5x concentration H30 8C) 60 ‘40 Mean bud growth (mm.) 2C) I 2 3 4 5 6 7 8 Node from top of plant Figure I0 - Cultivar 'Winter Carnival' grown in nutrient solutions for l9 days. The mean growth (9 plants) of axillary buds at nodes 2 and 3 significantly different at the 5% level by the F test. 33 TABLE 5.--Cultivar "Red Star" grown in nutrient solutions for 30 days. Mean axillary bud growth in mm.a Treatment Node from top of plant 1 2 3 A 5 6 7 '8 (A) X concentration 166 192 190 136 68 8 6 5 (B) 0.2X concentration 188 215 162 58 13 5 5 5 (C) 0.1x concentration 131 192 63 6 5 5 5 5 (D) 0.05X concentration 95 79 l 5 5 5 5 5 A vs. B through D NS ** ** ** ** * NS NS B vs. C and D' ** ** ** * NS NS NS NS C vs. D NS ** * NS NS .NS NS NS aEach figure is the mean of 8 plants. * and ** Orthogonal comparison significant within a column at the 5% or 1% level respectively by the F test. TABLE 6.-—Cultivar "Winter Carnival" grown in nutrient solutions for 18 days. Mean axillary bud growth in mm. b Treatment Node from top of plant l 2 3 A 5 6 7 Controla conc. 100 91 101 61 75 19 0.1 B conc. 105 109 91 A6 A7 6 A -.Zn conc. 99 96 89 A8 l6** l7 3 0.1 Ca conc. 57** 58** 50** 13** 23** 9 5 0.05 Mg conc. 83 75 72 38 15 10 3 - Cu conc. 85 95 87 53 Al* 13 A 0.1 K conc. A7** 36** 29** 10* 1A** 2 l a0.5X--Modified Hoagland solution. bEach figure is a mean of 5 plants. * and ** Mean differs significantly within a column from the control mean at the 5% or 1% level respectively by nonorthogonal F test. 35 Experiments covering the interaction of nutrition and light intensity demonstrated that increases in light inten- sity increased growth only at higher nutritional levels (Table 7). Significant differences were demonstrated at buds 1 through 3 with 1.0X and 0.2X modified Hoagland con- centrations. There were no differences at the 0.05X concentration. It has been a common observation for centuries that the relative availability of water can affect plant growth. An experiment designed to test the effect of reduced transpiration on axillary bud growth provided positive information. This experiment was run in the greenhouse with outside day temperatures above 90 F. Comparable growth of all buds was obtained when plants were grown under intermittent mist (Figure 11). Non-mist conditions produced more growth in the upper buds than in lower ones. Since axillary bud growth was stimulated or inhi- bited by changes in light intensity, nutrition, or water relations, interactions between the three factors were determined. Under high soil nutritional conditions (fertilization rate at 1 oz. per 2 gallons water) an approximate increase in relative humidity from 65% to 80% produced more growth in buds 1 through 3 but affected growth little in the other buds (Table 8). Higher light intensity (909,700 micro-watts/cm2) decreased growth in the top three buds but increased growth in buds 6 through 36 TABLE 7.--Cu1tivar "Red Star" grown in nutrient solutions for 35 days. Li ht intensity: high--226,2302micro-watts/ cm ; low--97,890 micro-watts/cm . Mean axillary bud growth in mm. Treatment Node from top of plant‘ 1 2 3 A 5 6 7 High light intensity- a a a 1.0x modified Hoagland 111 11Aa 98a 36 17a 3 la Low light intensity- b b 1.0X modified Hoagland 61 58 10 High light intensity— a a a a a a a 0.2X modified Hoagland 98 98 91 2A 20 3 1 Low light intensity- b 0.2X modified Hoagland A0 73 High light intensity— a a a a a a a 0.05X modified Hoagland A8 68 A5 11 5 2 1 Low light intensity- a a a a 0.05X modified Hoagland 5A 61 18 3 3 l aMeans (6 plants) within each column of two figures followed by different letters are significantly different at the 5% level by the F test. 37 I00 A Non-mist ,. ---- B Mist “ 80 E ‘5 so 5 a '3 «40 (.0 C 8 :; 2C> O I 2 3 4 5 6 7 8 9 I0 Node from top of plant Figure ll - Cultivar 'Mermaid' grown under intermittent mist and non-mist conditions for 2l days. The mean growth (7 plants) of the axillary buds at nodes 2, 7, 8, and 9 significantly different at the 5% level by the F test. 38 .umop m on» ma zao>fipoodmop Ho>oa RH no am on» um cESHoo m Canvas wadefimaswfim cowfiamQEoo Hmcowonpho*x cam * .mpcmad o no came ecu we madman comma m2 m2 ** m2 m2 m2 m2 ** ** ** 0 .m> m g. .... m2 * * m2 .... .x. m2 m2 0 9.8 m .m> Q mz * m2 mz m2 m2 mz mz m2 m2 a smooaco m .m> a awmm.m mm mm em mma mag NQH mag mmfi ama mma emw op eow.soaoaaam mEo\mppm3IoL0HE oom mom .ch AQV . soaoaszm E :H m w ma m: cm mm ow mm mm Hoa mm mEo\mppm3Iocowe oom.mom .ucH ADV . . mpHUHESm a . ems oo tom . . E am a m m OH m: om mm mm H2H 02H :za mEo\mupm3I090flE omm.mmH .ch Amv m a HE: m . eon op emm u.p. m CH m m w m m z m m H m occfia Aomimimmv o z .How m\.No H pod pcwaa mo QOp anm mpoz pump coepmmfiafippom spa: HH< fitszpm mucoEpmope m.EE cfl npzopw can mamaafixm cam: .maoo Hm con moaoancooca ocwafl anon use mmeHUHESQ m>wpmfiop 03» pops: Esopw socc< copaoo pcwflpm= am>HpH50II.m mqmga 39 9. With increases in both factors (80% relative humidity and 805,500 micro-watts/cm2), significant increases in growth were observed at nodes 3, A, 6, 7, 9, and 10. Plants grown with low soil nutritional conditions (fertilization rate 1 oz. per 10 gal. water) produced an increase in growth in buds l and 2 with an increase in relative humidity (80%) (Table 9). The remaining buds were not affected. There was less growth in buds 1 through 3 under higher light intensity (898,700 micro-watts/cm2) and no differences in growth at the remaining nodes. Increase in both factors (80% relative humidity and 805,500 micro- watts/cm2) produced a growth decrease at node 2 and a growth increase only at node 6. Various methods were used in attempting to correlate the environmental factors with a phyto-hormonal system. The excision of three combinations of axillary buds at nodes 2 through 5 showed significant increases in growth to the non—excised control at nodes 1 and 6 through 9 (Table 10). The excising of buds at nodes 2 through 5 versus bud excision at nodes 1 and 2 or 3 and A was also effective in increasing growth in buds 6, 7, and 8. No significance was found in excising buds at nodes 1 and 2 versus nodes 3 and A. Placing a notch above the axillary buds at nodes 5 and 7 stimulated growth in those buds whereas growth stim- ulation did not occur in buds at similar positions in A0 .pmop m on» an >Ho>Hpoonop Hm>oH RH Lo mm on» pm CEBHoo m cHszz meOHchme COmemoEoo Hmcowocupo** can * .mpcmHQ 0 mo some one opstm comma mz mz mz mz mz mz mz mz ca a. o .n> m mz mz m2 m2 ** mz mz mz ** m2 0 ago m .n> a mz mz mz mz m2 mz * mz *. mz o smooths m .n> a emm on com sowoassm mao\ooonauocoas oom.mom .ocH ADV emw oo Row Hoaoaaom .Ewm©.o m m m N w mm mm ow HHH :HH EO\mppm3IOL0HE 0mm nMMH .pCH ADV m .Em . ace oo emm soaoassm mo H H H m m w :H Hm am we we mEo\mpum3IopoHE oom.wmm .ch Amv .sw . ace oo eme soaoaasm me e a a a w a em Ha as we as mao\mooaeuoooaa oea.mam .ooH lav OH m m e o m z m m H m cacao Aomimimmv o m .Hom QH\.No a pod pcmHQ no no» Soak opoz open coHpmNHHHuLom csz HH< .p: mpg muCoEpmopB m.EE CH npzopw U59 mpmHHme :moz .osoo Hm soc noaoancoccw ccmaH anon cam onquHESQ o>prHoh 03» pops: csopw :occ< cooHoo pcprmz am>HpHsoII.m mqmHuoodmoL Ho>oH Rm on» at CESHoo m chsz pcmoHMchHm COmemoEoo Hmcowosppo** one * .mpcmHQ m mo some on» mH endem comma m2 m2 ** m2 * m2 m2 mz O .o> O m2 m2 * mz m2 m2 m2 m2 O one O .m> m m2 m2 m2 ** *s *s ** as O canons» m .n> a m O OH HH mm m: mm mm sHHocsH .sw\<HpH50II.:H mquB A6 .mpCmHQ w mo .pmop m ComHCmQEoo HBComOCpCOICOC mp mHo>HuoonoC Ho>oH NH Co Rm on pm Came HOCpCoo one Eopm CECHoo m CHCsz meCmOHmHCme wCoCCHU cmoz** UCm * CmoE me mH opstC Comma mm mm m mm N: *m: **mm *mw **mm .Edd ooomlmmmm *HH O: Hm mm HO *HO *HO *me **OO .Eaa OOOm OmmIOOa sonosa mm ON ON Om Om Om *HO **OO *aHO .saa OOHiamOz me O: mm mm OO we HO OOH mOH OcaOHO ooz O O a O O O m m H pCmHQ no don Eopm opoz .88 CH CHZOCw 639 szHHme Cmoz PCmEpwth .mmmp om Com CZOCw pCm .mHm>CmpCH hmfil: PM ®OH3p USN QPMU LOEHQ CO Umumwgp :UH®E&®Z: hm>HpHSOII.mH Mdm<8 A7 .omoo m CowHCmQEoo HmCowoanOICOC an Hm>oH mm on um Came HoppCoo on thm CEsHoo m CHCqu zHuCOOHMHCme mCGCCHU Cmoze .mpCOHd o no came mCu mH GCCwHC Comma m HH 0: *mm ow mm mm am» om mw ENIOHlde m NH mH ow :m on mm mm mm no 2mIOHIHpH30II.OH mqmH0>Hpomdwoa Ho>mH RH oCm mm on» pm Come HoppCoo on EOCC CEBHoo m CHCsz szCmOHCchHm mCmCme Cmoz** pCm * .mpCmHC w mo Come on» mH mpstm Commm Hm OH *mm om mH mm memo Hm mm mm CHHOCmH omsm ow mm am an om mm *mm Hm Hm mm ENIOHI¢mH we: m **mm mm **o: mm om om mm mm EMIOHIoom oonooos emcee sOOHoO Ocmems CO>HOHOOII.HH mHmaH .oH USN «w «m 50 .umop m ComHCmoEoo HmCowOCpCOICOC an zHo>HpoQOoC Ho>oH OH HO HO me pm Came HoapCoo on» Eomm CECHoo m CHCsz OHHCOOHCHCme mCoCCHU Cmoz** OCO * .mpcde O mo COGS mCu mH oCstC Commo x . ..oCoo EmIoH m H <39 0 no zOIOH x O O ocoo Om 2O O H NO O OO H OO OO 2 IOH x O.m .OOH+OmOzs O *OO **Om OO HH Om ssHH zOIOH x fluuHosonaosOHsHOIO .m O **OO O OO OH OH ssHH onm ooCOHOC =Hw>HCCmo HmpCsz Cm>HpH30II.OH mqmHpooomoC Ho>oH OH HO HO on» pm Came HoppCoo 8C» Eopm CesHoo m CHCsz OHpconmHCme mCGMCHU Cwozxs eCm * U .UHom oHCOHQOCQOCOHCOHQo .UHom oHpoowszCoCCOCOHCOHQIO .m n .UHom OHEMHQEQSQ HhQQCQMZIlem O O HN OO OO OH HH OO OH *OHO zOIOHI OOO N N HN OO NO HO NO *OO OH OO zOIOHI OOO H O O HO OO OO OO HO OO OO anOHI ONOO N O OH ON OO OO OO OH OO OO zOIOHIOIO .N H O HH HO OO OO OO OH OH OO zOIOHIOIO .N H O HN OO OO HH OO OO *OOO *OOH zNIOHIOIO .NO H O NN OO OO OO NO OH NH OO zOnOHIOOsOHO N O ON OH OO OO OO OO OH OO zOuOHIOOcOHO O *OHN *OOO OH OO OO OO HH *OO **HO zNIOHIOOOOHOO O O NN HO OO NO OO OO OO OOH HospsoO OH O O H O O O O N H PSMHQ .HO mop EOcHM @002 pcmapmmhn—p .88 CH szopw pan OCmHHme Cmoz U .mzmc om Com Czopw mpCmHQ va pCmHQ poCoCHQ on» mo QHp on» Co Umode Gamma HmoHEmCo ICHHOCOH Csz copmopu =oCC¢ CocHow prHsz Cw>HpH30II.OH mqmHpoonoC Ho>oH RH Ho Om on» we Came HoppCoo can Soap CEdHoo m CHCsz meCmoHMHCme mHoHCHU Cmoz** pCm * .npcde O Co cams on» OH ohstC commc .OHom OHcoHdoCdosoHCOHmo .UHom oHuoomONOCoCQOCOHCoHQIO .m n .UHom oHEMHMCpCQ HOCHCQNZIHIZM om O HH OO OO OO NO OO OH OO zOIOHI «mo OO OH OO OO OO NO OO OO OH NH zOIOHI ONO OO OH OH OO OH OO OO HO OH OO zNIOHI «Ono OO ON HO OO OH OO HO HO OH OO zOIOHIOIO .N OO HH OO OO NO OO OO OO OH OH 2 IOHIOIO .N mNH N **m Om **m **m *mm *mm 05 HO SWIGHIQI: «ND mOH OH OO OO NO HO OO OO OO OH 2 IOHIOOOOHO OO NO OH HO NH *OO OO OO OH NO EmIOHIaOOOHO 0: **mz *Om *OO mm **Om OO *me **mO **0O ENIOHIQNCNHonm poCUHOC =oCC< CopHow quHHmz Cm>HpH30II.om mqm o» Oomoqu :OCC< mmmoCHCm ONCOCm: CO>HHHOOII.OH Hm OCH Hm CNoE HOCHCOO OCH EOCH CEBHOO m CHCHHB OHHCOOHHHCme OCOHCHU COOSx .mHCmHQ O CO Cmoe OCH mH OCsmHm Comma ON O O OO HO OOH HNH OHH .eaa ONI-sHONcHO N O NN HO OO OOH HOH OHH .aaa ON--OHOH--OO HN OH ON OO OO OO NNH *OO .eOO ONIIOOH O O H OO OO OOH OOH OOH ONOOHO Hoz O H O O O O N H - UmmperH HCOHQ mo OOH EOCC OOoz mO>NOH O Ooe I .- .lr ll IIHCOEHOOCB O.EE CH CHzon USC OCOHHme COO: .mzwo mm Com CZOCw OCm .mHm>COHCH ONOIO Hm OOHBH UCN OHOO CoCHQ CO OOHNOCH :OCNOHCCCO: CN>HHHOOII.OH Hm OCH Hm COOS HOCHCoo OCH EOCO CECHOO w CHCHHZ OHHCNOHchmHm mCOHHHU Cmozx .mHCOHQ O mo COOS OCH mH OCstm CommHW O O H O HN OH OO *OO .EOO OOHIIOOH O H H OH NN OO OO OO .eOO ONIIO HOHIIOO O O H O ON NO OO OO .EOO ONIIOHHNNHO O H O OH NO HO OO OO .EOO ONIIOmOz O O O OH OO HH HO OO HNNOO oz O O O O O m m H .HCNHQ mo OOH SOHO OUOZ HCOEHOOCB .m .58 CH CHZOCw CBC OCOHHHXO COOS .OONO ON COO CBOCw OCN mCHONCQO OC UOHNOCH :COOOG OHCoCO: CO>HHHSOII.COHCH OOOnm HO OOH3H UCO CoCOQ HO wCOmOCQm OC UOHOOCH UHOECOE= CO>HHH30II.<: mqm<9 .72 60 50 4F) 30 20 l0 lNTENSITY-MlCRO-WATTS O 400 500 600 700 750 I050 WAVE LENGTH IN MlLLl-MICRONS Figure 1 A - Typical light spectrum as recorded in a green- house at noon on a bright day in August. 73 8C) 7() 6C) 5() 4() 3C) 2() IO * INTENSITY - MICRO-WATTS ’ 400 '500 600 700 750 1050 WAVEiENGTH IN MlLLl-MIGRONS Figure 2 A - Light spectrum resulting from.the use of cool white fluorescent tubes with a blue Rohm.and Haas (2424) filter. 74 90 80 7O 60 50 4O 30 20 IO INTENSITY - MIGRO‘WATTS 400 600 700 750 IOSO' WAVE LENGTH IN MILL|-M|GRONS Figure 3 A - Light spectrum resulting from the use of cool white fluorescent tubes with a red Rohm and Haas (#2423) filter. 75 7O 60 50 R-IOO 4O 30 20 INTENSITY-MICROWATTS 400 500 600 700 750 I050 WAVE. LENGTH IN MlLLI-MICRONS Figure 4 A - Light spectrum resulting from the use of cool white fluorescent tubes with the addition of incandescent flood bulbs filtered by a PR 700 filter. 60’ INTENSITY-MlORO-WATTS 400 500 600 700 WAVE LENGTH IN MILLlj-MIGRONS Figure 5 A - Light spectrum using cool white fluorescent tubes as the main source with the addition of two 25 w incandescent bulbs. 77 90 80 R-IO 7O 60 50 40 30 20 INTENSITY - MICRO‘WAT TS 400 500 600 700 750 I050 WAVE 'LENGTH IN MILLl-MICRONS Figure 6 A - Light spectrum resulting from two layers of red cellophane (Dennison) as a filter and using cool white fluorescent tubes as the main light source. 78 90 3° R-IO 70 60 I? so I 40 3° 1%] 20 INTENSITY - MICRO-WATT S 406 soo 600 790 750 l050 WAVE LENGTH IN MlLLl-MIGRONS Figure 7 A - Light spectrum resulting from two layers of blue cellophane (Dennison) as a filter and using cool white fluorescent tubes as the main light source. "III IIIIIIIII III IIIVIIIIIIIIIIII IIIIIIIIIIES 3 1293 0307] 3949