AlR-MC:’E£LK¢E W P3»§.‘£‘E?E‘ZY§.§NE FEEL AND GRCZ‘V'J'KE $335“ "2‘ can-‘1 ‘E‘hessfs $3? {Jim flame a§ {‘i‘. S. MECHI‘CEAH STAT; ES‘EVERSIW Fi‘&i‘;323 $5. '3’. Cififing W565 1:83 AIR-LAYEAING WITH COLOHED POLYETHYLENE FILM AND PLANT GfiUwTH dEGULATORS By FRANCIS F. '1‘. game AN ABSTKACT Submitted to the College of Agriculture of Michiggu State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Horticulture 1956 Approved _z(:bé;41é2 0[;Z§é;锢4Z52L// #JL 1‘ b q—xo- “to FRANCIS CHING ‘ ABSTRACT Though previous workers have obtained favorable root formation in air-layering with colored polyethylene film and growth regulators, few workers have made an attempt to grow the new plants after they were severed from.the parent plant. An attempt was made to determine the most suitable and practical methods for rooting and removing air-layers for further development of the new plant. I When rose plants were air-layered with naphthaleneacetic acid at 100 p.p.m., the greatest amount of root formation was produced. Though these roots were short and stubby, they all producedheavy root growth after they were severed from.the parent plant and potted. Subsequent top growth of the cuttings after transplanting revealed that there was a difference in the degree of top growth, as well as root growth, de- pending upon the concentration of naphthaleneacetic acid used. Naphthaleneacetic acid was not effective in promoting root growth at the concentrations used in the rooting media of air-layers of tomato plants. Though maleic hydrazide inhibited root growth at the concen- trations used, the development of root formation was not affected. Treatment of geranium plants with naphthaleneacetic acid was not effective in promoting root formation. However, the highest percentage of rooted plants occurred when the plants were grown under a continuous photoperiod. AIR—LAYEAING wITH COLORED POLYETHYLENE FILM AND PLANT GROWTH REGULATORS By FRANCIS F. T. CHING A THESIS Submitted to the College of Agriculture of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Horticulture 1956 ACKNUHLEDGEMENT The author wishes to express his indebt- edness and sincerest appreciation to Dr. Charles L. Hammer for his guidance and encouragement in directing the course of this investigation, and to Drs. G. P. Steinbauer, C. E. Wildon, J. E. Moulton, and A. E. Mitchell for their guidance and editing of the manuscript. TABLE OF CUNTENTS Page 11in “UDU C'I‘IUN O U C O O O O O C O C O C Q C O C O C C . O . . REVEW 01“ THE LITELMTUKE e e e e e e e e e e e e e e e e e e MATERIMS AN D METHODS O O O O O O O O I O O O O O O 0 0 O O O 0000» Preliminary Studies . . . . . . . . . . . . . . . . . . Air-Layering of Rosa hybrida, Var. Queen Elizabeth, Using various Concentrations of Alpha Naphthaleneacetic Acid With Colored Polyethylene Film . . . . . . . . . . lO Air-Layering of Lyc_opersicon esculentlm, Var. Commne, Michigan X Ohio, With various Concentrations of Alpha Naphthaleneacetic Acid Under Different PhotOperiods . . ll Air-Layering of Pelargonium zonale, Var. dadio Red, Using various Concentrations of Alpha Naphthaleneacetic Acid Under Different Photoperiods . . . . . . . . . . . 13 Air-Layering of Lycopersigon esculentum, Var. Commune, Spartan Hybrid, Using various Concentrations of Maleic Hydrazide . . . . . . . . . . . . . . . . . . . . . . . 13 RE‘JSIH‘TS o O O O O O O O O O O O 0 O O O O O O O 0 O O O O O O 13 Air-Layering of Rosa gxbrida, Var. Queen Elizabeth, Using Various Concentrations of Alpha Naphthaleneacetic Acid With Colored Polyethylene Film . . . . . . . . . . 15 Air-Layering of EchEersicon escglentum, Var. Commune Michigan X Ohio, [king Various Concentratiom of Alpha Naphthaleneacetic Acid Under Different PhotOperiods . . Air-Layering of Pelargonium zonale, Var. Radio Red, Using Various Concentrations of Alpha Naphthaleneacetic Acid Under Different Photoperiods . . . . . . . . . . . Air-Layering of LycoEersicon esculentum, Var. Commune, Spartan Hybrid, Using Various Concentrations of Maleic HydraZid. O O O O I O O O O 0 O O O C O O O O O O O O O SUMMARI. . . . . . . . LITERATURE CITED . . . O O O O O O O O O O O O O O O O O O O C O O O O O Page 42 A7 50 52 INTRODUCTION The art of air-layering,as a means of propagation, has been known in China (16) for many centuries. Air-layering has received new impetus within the last ten years due to the develOpment of plastic films which will maintain moisture and allow for suitable exchange of gases when used as wraps around a rooting media. In 1947, Grove (8) used "Pliofilm" and later, ”Vitafilm" for air-layering of the Lychee (Litgh; chinensis). Air-layering with pohr- ethylene film was later reported by Hyman in 1951 (23) and Creech in 1951. (1.). Though Wyman (23) obtained some very favorable results from.his methods of air-layering, he made no attempt to solve the problem of cutting the potential plants from the parent and getting them to grow after they were potted. His few attempts to pot these plants were un- successful and he suggested that a further study should be made to de- tenmine the best methods of severing and potting the new plants for further development. A further advance in the art of air-layering has been the intro- duction of growth promoting hormones as an aid in rooting. Using Hor- modin No. 3, in which indolebutyric acid is the active ingredient, WVman (23) indicated that in some cases, excess amounts may have been applied causing a hormone injury. Other workers (17) have found that growth promoting hormones are of little value in stimulating root initi- ation with air-layers. With these difficulties in mind, an attempt was made to determine the most suitable and practical methods for rooting and removing the air-layer for further development of the new plant. REVIEW OF THE LITERATURE In the "Power of Movement of Plants", Darwin (5) wrote that this movement was caused by phototropism and geotropism. The theory of Sachs, as reviewed by Went and Thimann (22), was that specific chemical substances influenced organ develOpment as they moved from one part of the plant to the other. Van der Lek, according to Went and Thimann (22), concluded that root formation was dependent somewhat upon the presence of sprouting buds although some roots could be formed without the presence of buds. He assumed that a growth substance was fermed in the buds and transported downward to the basal portion of the cutting. In 1905, animal physiologists introduced the word "Hormone", a Greek word meaning I'Activity Arouser", a substance that is produced in one part of the body and translocated to other parts of the body by means of the blood stream. The word "Auxin", from another Greek word "To Increase", was later applied to synthetic substances which induced hormone-like responses when applied to plants. Carbon monoxide, ethylene and other unsaturated hydro-carbon gases induce many responses in common with other plant hormones (25) and were recognized as physiologically active compounds before hormones were recognized. Though the chemical structures of these compounds are Very different, the effects are similar. This fact lent support to the assumption that growth substances do not act directly but enter into complicated interactions with natural substances to produce a given result. Fitting and Boysen-Jensen in 1910, according to a review (25), recognized that curvatures of shoots due to phototropism and geotropism involved an influence of a chemical nature. Peal (25), in 1918, showed that the growth of a certain plant organ is controlled by its tips. These discoveries led to the quantitative determinations of "growth substances" by bio-assay methods. Since then, many synthetic substances have been found that will induce cell elongation or enlargement and many different methods have been devised for the application of these substances. In 1935, Hitch- cock (11) described the activity of 3-indole propionic acid, and in the same year, Zimerman and Wilcoxon (27) discussed some chemical growth substances which caused initiation of roots. Substituted phenoxy and benzoic acids were added to the list of growth substances by Zims merman and Hitchcock (26) in 1942. These two groups of substituted acids marked the beginning of a new phase of plant hormone research by scientists all over the world. ‘With this discovery, many new growth substances have been synthesized. Plant hormones give very different results on various plants, and furthermore, give different results when.used in various concentra- tions. Also, growth regulators produce different types of root systems (24). Indole compounds usually produce a more fibrous root system than alpha naphthaleneacetic acid (NAA), and in addition, indolebutyric acid does not inhibit the growth of terminal buds as much as NAA. The discovery that indoleacetic acid was an excellent root- fOrming substance led to its practical use in the rooting of cuttings (1). Casper (3) used a mixture of lanolin and indoleacetic acid. Hitchcock and Zimmerman (12) used a solution of crystalline acids, soaking the cuttings for a number of hours. A hormone powder, followed later by a "quick dip" method of a concentrated solution, was developed by hitchcock and Zimmerman (13). Methods of applying plant hormones are reviewed by Stoutemyer (20). These methods include the powder prepara- tions, the concentrated solution dipping method, and the prolonged soak- ing of cuttings in dilute solutions. Ferri (6) found that synthetic growth substances applied as solutions to the soil of potted tomato and cleome plants can be absorbed and transported upwards in amounts sufficient to induce root formation on leaf cuttings sometime after treatment. Ferri also found that the upward movement of growth substances is independent of the activity of living cells. ‘When growth substances were applied to the killed bases of tomato cuttings, the leaf cuttings above the treated areas were still able to produce roots. Though root inducing substances are used by commercial propaga- tors and amateurs, the total sales volume is not very great. Because these substances are very effective at very low concentrations, the same solutions or mixtures may be used over and over again. Basal portions of cuttings of tomatoes may be rooted in a water solution of indolebutyric acid of l p.p.m. and grape cuttings in an 80 p.p.m. solution. Some species root better as greenwood cuttings while others do better as hardwood cuttings. Zimmerman, in a review (2h), has discussed some of the uses of hormones. With the use of a variety of hormones, seedless tomatoes, eggplant; cucumbers, and squash.may now be produced. In an attempt to use growth promoting hormones to induce ovaries to develop into fruit without pollination, Gustafson (9), in 1936, was the first to produce seedless fruit of tomatoes, petunias, salpiglossus, and peppezs‘ty artificial methods. Marth (1h), using a-naphthylmethylacetate for treatment of rose bushes to prolong the dormant period in common storage, found that a vapor is most effective when applied to plants fully matured when stored. Shoot growth was also inhibited on immature plants but the effective period after treatment was of shorter duration and plants were more susceptible to injury as a result of treatment than were more mature plants. Dormancy of evergreen fruit trees may be induced with sprays con- taining sodium naphthalene acetate (18). When.used on 1ychee, matura- tion of vegetative terminals is hastened and further growth is prevented thus giving rise to most favorable conditions for development of flower inflorescence. Alpha naphthaleneacetic acid (NAA), when properly applied, can inhibit buds, induce roots on cuttings and prevent abscission layers from forming. After treatment with NAA, potatoes can be stored for a long period of time without sprouting or shrinkage and fruit trees can be prevented from flowering. Flowering of ornamental shrubs can be delayed and the pre-harvest drOp of apples may be prevented. Merlich (15), using NAA and other hormones in varicma concentrations, has found that an advance or delay in the time of differentiation of flower~ ing may be controlled in the pineapple plant. He was also able to delay maturation and ripening from one week to two months, increase weight and size of fruit, and obtain a more desirable peduncle that is larger, stronger and more fibrous. Air-layering is a method of propagating difficult-to-root and/or stiffly-erect plants. Where plants are naturally difficult to root by cuttings,:mound and tip-layering is practiced. However, some plants are not adapted to mound or tip-layering, but are adapted to air-layering. A plant propagated by air-layering will be a genotype of the parent plant. By this method of propagation, branches, many times longer than a cut~ ting may be rooted. In 19h7, Grove (8) used a type of plastic as a wrap to air- layer lychee and subsequently, received a patent for his process. In 1951, Hyman (23) described preperties of polyethylene film showing its permeability to gases and its moisture holding capacities. wyman also used a root inducing substance as an aid to rooting and ob- tained some very good results on rooting. He did not pursue the problem any further as the operation of growing rooted plants was considered be- yond the scope of his experiments. Creech (A), in 195k, experimented with air-layering and carried his experiments further to include subsequent growth of new plants after they had been severed from.the mother plant and also fertilized the stock plant while root fermation was taking place. Immediate defolia- tion of leaves of the new plants took place when transplanted to peat. Both'wyman and Creech have been cognizant of the fact that even though the subsequent new plants form a substantial amount of roots, they may not survive transplanting. Storey (19) has suggested that different colors of plastic fihn may produce a different effect on fonmation of roots. Besides the use of plastic films and hormones, methods of air- layering have remained basically the same (2,4,7,10,17,21). A stem or branch, not more than two inches in diameter, is either notched or girdled and a rooting media such as moist sphagnum.moss is placed around the scored area. Next, a wrapping or tie of some sort is applied to hold the rooting media in place. During the time of root formation, the rooting media must be kept moist until roots are observed and the new plant severed from the mother plant. MATERIALS AND METHODS PRELIMINARY STUDIES Preliminary experiments were tried on the @233 hybrids, var. Queen Elizabeth. Stems, approximately one-quarter inch in diameter and not more than a year old, were scored by the complete girdling technique in which a ring of bark, approximately one-quarter inch wide, was re- moved and a handful of sphagnum.moss, which was soaked overnight, was squeezed of excess moisture and applied around the girdled area of the stem. A polyethylene film six inches square was then secured around the moss and the ends of the film affixed to the stem above and below the moss by means of 'Twist-Ems'", Figure 1. Four weeks after air-layering, the canes were severed below the girdled area and it was observed that although there was good callus formation, there was no visible root formation. The cuttings were then uniformly decapitated leaving two nodes above the girdled area and, in addition, one-half the remaining leaves of each cutting were removed. The cuttings were then transplanted to four—inch clay pots containing a potting soil. Axillary buds began to grow by the end of the first week. After the third week, however, the cuttings had lost the remaining portion of their.mature leaves and after five weeks, most of the cuttings were dead. m e m m m m Air-layering of Ban lyethylene film. Figure l. with colored po 10. AIR-LAYERING OF ROSA HYBRIDA, VAR. QUEEN ELIZABETH, USING VARIOUS CONCENTRATIONS OF ALPHA NAPH‘I‘HAIENEACETIC ACID WITH COLORED POLYETHYLENE FILM Since preliminary trials of air-layering‘figgg’hybgigg, var. Queen Elizabeth, indicated that this plant was relatively difficult to root by ordinary air-layering methodS, this variety was chosen for the first series of experiments. The experimental roses were obtained from plants growing on greenhouse benches at the Plant Science Greenhouse, Michigan State University, East Lansing, Michigan. Polyethylene film, .0015 inches in thickness, was obtained from the Bakelite Company in two different colors, black and white. Whereas previous workers applied a root inducing hormone to the scored area in the form of a dust or in a lanolin mixture, NAA was incorporated into the rooting media, sphagnum moss, by soaking the moss overnight in different concentrations of NAA. By this method of application, NAA would remain in constant contact and concentration with the scored portion of the stem.than if a dust or lanolin.mixture were used. The concentrations of 10 p.p.m. and 100 p.p.m. NAA were prepared by first dissolving the chemical in 95% ethyl alcohol and then diluting by adding tap water. The sphagnum.moss was soaked overnight in either tap water or in solutions of NAA. The air wraps were secured at the ends by tying with four-inch "TwistéEms‘" as in the preliminary experiments. Scoring, method of application and type of stem.used were the same as used in the prelimdnary experiments. There were twelve replications for each of the six variables for a total of seventybtwo treatments. 11. After the plants had been layered for two weeks, it was noticed that there was a difference in temperatures between layers wrapped with white film and those wrapped with the black film. In order to determine the temperature fluctuations, thermometers were inserted into the air- layers and temperatures recorded at noon of each day. After six weeks, the layers were removed by severing the stem below the girdled area and the amount of rooting and callusing was recorded. The stems were then decapitated to two nodes above the girdled area and one-half the remaining leaves of each cutting were re- moved. The individual cuttings were then transplanted to four-inch clay pots using a potting soil. In addition, fresh non air-layered cuttings of the same variety were planted in the same manner in order to observe the formation of roots by this method. The amount of growth made by axillary buds was recorded each week. Four weeks after trans- planting, the roots were washed and the root growth was recorded. The plants that were treated with 100 p.p.m. NAA and the plants that formed only a heavy callus with 10 p.p.m. NAA, were divided into two groups; a few plants of each treatment were washed at the end of four weeks and the remainder were washed eight weeks after transplanting. AIR-LAYERING or LLQOPERSICON Escuw VAR. comma, MICHIGAN-OHIO, usnc VARIOUS CONCENTRATIONS OF NAA UNDER DIFFERENT PHOTOPERIODS Seeds of the Michigan-Ohio Hybrid-variety of tomatoes were sown in a flat November 19, 1955 and were transplanted to eight-inch clay pots four weeks later. Two weeks before air—layering, one-half the l2. potted plants were placed under continuous light supplied by four AO- watt white florescent bulbs. These plants remained under these lights for the duration of the experiment while the other plants remained under a normal day-length. The tomato stem was scored by removing the sixth leaf above the cotyledon and a cut was made into the stem thus removing a portion of the stem that extended into the region of the xylem. White polyethylene film of .0015 inches thick was used as wraps and the ends were secured with four-inch "Twist-Ems". Concentrations of NAA and method of application of the rooting media were the same as used with the roses. There were fourteen replications for each of six variables for a total of'eighty-four treatments. In addition, each variable was divided so that one-half the plants were air-layered for two weeks and the other one-half were air-layered for three weeks. Two and three weeks after treatment, the air-layers were re- moved by severing the plants below the girdled area and amount of root- ing was recorded. The cuttings were then decapitated to two nodes above the girdled area and the cuttings defoliated. The plants were then transplanted into eight-inch clay pots and returned to their respective photOperiod. A nutrient solution containing 10-6-h fertilizer was applied to the new plants the second week after transplanting. The amount of growth.made by the axillary buds was recorded for each week and at the end of the fourth week the roots were washed and amount of root growth was recorded. 13. AIR—LAYERING 0F PELARGONIUM 20mm, van. mum) man, USING mucus CONCENTRATIONS or NM AND DIFFERENT PHUTOPERIODS Potted Pelargonium goggle, var. Radio Red plants, approximately six months old, were used. The stems were scored four inches below the terminal point of growth by removing a portion of the stem one-quarter inch long and one- eighth inch wide on opposite sides of the stem. White polyethylene film .0015 inches thick was used as wraps and the ends were secured with four-inch "Twist-Ems'". Concentrations of NAA and the control, and the method of appli- cation were the same as used with the roses. Previous to air-layering, one-half the plants were placed under continuous light for one week. The light was supplied by four AO-watt white flourescent bulbs. There were five replications for each of six variables for a total of thirty treatments. In addition, an attempt was made to root cuttings in sand under a normal day-length. Four weeks after air-layering, the wrappings were removed and amount of root fermation was recorded. AIR-LAYERING 0F LYCOPERSICON ESCULENTQE, VAR. COMMUNE, SPARTAN I'HBRID, USINGVARIOUS CONCENTRATICNS 0F MKLEIC HYDRAZIDE Ten week old plants of the Spartan Hybrid variety of tomatoes were used for this experiment. Sphagnum.moss was soaked overnight in tap water and in solutions of 5 p.p.m. and 50 p.p.m. of maleic hydrazide. White polyethylene film of .0015 inches in thickness was used for wraps. Methods of scoring and application of the Sphagnum moss were the same as previously used with the treatment of tomato plants using NAA. No photoperiod was involved in this experiment. There were seven treat- ments for each of three variables. At the end of two weeks, the wrap- pings were removed and amount of root formation was recorded. 15. RESULTS AIR—LAYERING OF ROSA HYBRIDA, VAR. QUERN ELIZABETH, USING VARIOUS CONCENTRATIONS 0F ALPHA NAPHTHALENEACETIC ACID WITH COLORED POLYETHYLENE FILM various concentrations of NAA produced different types of root formation. Root growth and top growth after transplanting indicated that different concentrations of NAA had a residual effect on plants as to the type of growth that was produced. It was found that rooting and callusing was heavy when air- layers were treated with NAA as compared to controls, Tables I and II. When air-layers were applied with 10 p.p.m. NAA, one-half the air- layers produced a moderate amount of roots which were long and slender With a small amount of branch roots, Figure 2. Treatment with NAA at 100 p.p.m. increased the percentage of air-layers showing heavy root formation, although the roots were very short and stubby which indicated that NAA at this concentration may seriously inhibit subsequent root growth, Figure 3. There were considerable differences in amount of root growth after air-layered plants were transplanted and allowed to grow for four and eight weeks, Tables III and IV. Plants that had formed roots when air-layered with 10 p.p.m. NAA produced considerable root growth four weeks after transplanting. Cuttings which had formed a heavy root growth when air-layered also produced the heaviest amount of root growth When transplanted, Figure A. These roots were fibrous and branched. 0f the roots that were present after being transplanted for four weeks, 16. Figure 2. Root and callus formation on air-layers of Rosa var. Queen Elizabeth in relation to different treatments with HAA. 100 p.p.m. NM. Center, 10 p.p.m. BAA. Right, control. m9, Left, Figure 3. Root forntion of Rosa fibrida, var. Queen Elizabeth, when aizhlayered with 100 p.p.m. NM. 17. Figure 1.. Root growth of Rosa mbrida, var. Queen Elizabeth, four Wake after transplanting in relation to root formation when air-layered with 10 p.p.m. NM. Left, moderate root fonnation when transplanted. “Slit, heavy root formation when transplanted. 18. l9. .anoEumohp node cw mmcwpudo NH seam opoawpmo o>wpoonnsn m we: wcfipOOM «a common .H No.02 mo. mo. mo. .add 03 and B23 mo. “8.0m .sdd 2 one; mo. mo. mo. «0.03 Houses". Eng mo. mo. and .add 09” RMem Rbeg R0. mOeom eEeQeQ OH Now-Hm mo. mo. Rm.m au.ao Homecoo h>eom adwcoz psqu ocoz mmweaom muoom no 9:5054 <42 mo :ofluenpcoocoo ocoabzpozaom no peace mnohmaluw< mo weapoom so some: ocoahcpohaom \ ? 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There was also a new callus forma- tion at the basal end of the stem. Plants that had formed very short stubby roots when air-layered with 100 p.p.m. NAA produced heavy root growth four weeks after trans- planting, Figure 5. Although root growth was heavy, there were no branch roots. After eight weeks, these same plants produced a very heavy root growth and in a few cases, top growth. Where top growth was present, there was a deveIOpment of fibrous roots which indicated that there was a correlation between top growth and type of root forma- tion, Figure 6. Plants with only a callus, formed under the air-layer treatment with NAA at 10 p.p.m. deve10ped a light to moderate amount of roots eight weeks after transplanting. A new callused area formed at the basal and of these cuttings and it was from this area that most of the roots originated. Roots were of non-fibrous type. Non-air-layered cuttings, planted in pots, were examined after four weeks. With one exception, all of these cuttings were without any visible roots. Average height of axillary bud growth after transplanting was recorded, Table V. Shoot growth of non-air-layered cuttings develOped immediately. By the end of the fourth week, most of these plants had lost their mature leaves and by the end of the fifth week, most plants were dead or dying, presumably due to lack of water and nutrient absorp- tion. Cuttings, which developed long, slender and fibrous roots when air-layered with 10 p.p.m, of NAA, were initially slow to develop new shoot growth. After seven days, however, tap growth exceeded that made Figure 5. Root growth of Rosa fibrin, var. Queen Elizabeth, four weeks after transplanting in relation to different treatments with NAA when air-layered. Left, 10 p.p.m. NM. Right, 100 p.p.m. NM. 25. Figure 6. Variations in root growth of M Mg, var. Queen Elizabeth, air-layered with 100 p.p.m. NM. Eight weeks after transplanting. Left, plant edth ne branch roots and no top growth. Right, plant with branch roots and top growth. 26. .mpcmad m mo owepo>< .m .mpqmaa b we ommuoaé .N .mpceaa m no owmno>< .H m.m : 39m m.m : Sub m.m = new Inns a cam m.b O.m e st w.m O.m : flhm m.N m.N : flaw m. o.H xooz and nepoox magnum mmpoomwmsounaa Hmsoom oz ¢ Idszwda OOH eflum.m OH mwmwppso wcaucmaamcmaa «<2 new: nepoMmHIuw< voucheauufim :02 nopm< exec; mcwpcmaamcmua mo 0529 as emceeuno mo :0 essence mndpceaamemss nopm< .npeneawam cameo .ue> .eewunxm snow mo whommannw< no nozoao pom Head mo .maopoafipcoo ca .unwfiom emeno>< > mqmda 27. by non-air-layered cuttings. Most t0p growth was made by plants that had heaviest root growth. By the end of five weeks, some of these plants Ind lost all of their mature leaves. All cuttings, which were air-layered with 10 p.p.m. NAA and which formed only a callus, with one exception, did not form any tOp growth. The reason shoots did not develop could have been due to lack of roots which thus caused a deficiency in the accumulation of nutrients and food material required for growth. Although root initials may have been present in the callused area, the callus may have hardened when the cuttings were transplanted. It is also possible that the NAA may have inhibited the shoots. Four weeks after transplanting, three of the plants that had been air-layered with 100 p.p.m. of NAA produced top growth, although all plants had produced a heavy root growth. Eight weeks after trans- ;flanting, where there was top growth, branch roots were present. Re- sults of this experiment indicated that air-layering with 100 p.p.m. of NAA will inhibit shoot growth, but not root growth, after transplanting. Furthermore, eight weeks after plants were air-layered with 100 p.p.m. NAA, all cuttings retained their mature leaves thus emphasizing the fact that NAA will prevent formation of an abscission layer and may also give added life to the leaf. The use of different colors of polyethylene in air-layering apparently had no effect on formation of roots, although there was a difference in temperatures of the air-layers, Table VI and VII. 0n sunny to partially sunny days, the air-layers with black Polyethylene film produced highest temperatures. While a maximum 28. ‘N.0N ~.~0 0.00 Awiee 0400 0i00 «mama .0>< 0.m0 0.00 0.00 0.00 0.H0 0.00 0.00 0.00 0.00 0.00 $.m0 0.00 0.00 0.00 N.m0 0.m0 0.00 0.H0 0.00 0.00 0.00 0.m0 N.00 0.00 0.00 N.m0 0.00 0.m0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.m0 0.00 0.00 0.00 0.00 0.00 0.m0 0.00 4.H0 0.00 q.m0 0.m0 0.m0 0.00 0.00 0.40 N.00 0.00 0.00 4.N0 0.00 endumpowx eRSAWAmm|. .!I,.. ---..:v-.:tnI!Il lane n04 000:3 xomam lava ufi< opazz xomam ocoaaepawmdm 00 00H00 00:00 0000 no 0000 M0000 onoa um Hem Ho hoaoo 00000 once go .000 Hmmmw .0000 macaw haaeaunmm op madam no .000000000 amuse .ee> .mefinnxe emom no mneamalnfl< no Apfioncoonem :00 monsoeoodaoa HoeuopeH was 8002 H> MAm mqmde 30. temperature of 96.80 F. was recorded with plants air-layered with black polyethylene film on the sunny side of the bench, the highest room tem- perature attained was 80.00 F. High temperature when white polyethylene was used for wraps of air-layers on the sunny side of the rose bench was 89.6° F. On sunny to partially sunny days, but on the shady side of the rose bench, the air-layers with the black polyethylene had only a slightly higher temperature than the room temperature while temperatures of the air-layers with white polyetl'wlene were always lower than the room temperature. 0n cloudy to partially sunny days, the fluctuation in tempera- ture, between the shady and sunny sides of the rose bench with the different colors of polyethylene, was at a minimum. This study on roses has indicated that the methods and materials used in air-layering are favorable to the propagation of plants that are difficult-to-root. Use of NAA in concentrations of 100 p.p.m., though it appeared to be detrimental at first, was in many respects, beneficial. After a plant is air-layered, severed from the original plant and transplanted, it is desirable that tOp growth remain inactive While the roots have an opportunity to deveIOp. NAA at 100 p.p.m. will inhibit shoot growth without any inhibiting effect on root growth. The type of root formation produced, when rose plants were air- layered with 100 p.p.m. of NAA, may be most desirable. When the newly formed plant is transplanted, the sphagnum moss may be removed without damage or breakage to the roots. By removing the sphagnum moss, all roots will be in direct contact with the soil for further growth and optimum conditions for nutrient uptake. Furthermore, NAA at. concentrations 31. of 100 p.p.m. prevented fall of mature leaves. There were no apparent differences on root formation between black and mite polyethylene men used for wraps of air-layers. How- ever, the lower temperatures recorded when white polyethylene was used for wraps indicated that this color of polyethylene may be most favorable to use. Most air-layering is practiced in the spring and summer when air temperatures are high with strong light intensities. As the maxi- mum temperature for Optimum root formation is approximately 85° F., white polyethylene will keep the internal temperatures of air-layers to a minimum. AIR-LAYfiiIhG OF LYCOPERSICUN ESCULENTUM, van. COMMUNE, MICHIGAN X OHIO USINGVARIOUS CUNCENTflATIONS OF NAA UNDER DIFFERENT PHCTOFERIOUS When tomato stems were air-layered with white polyethylene and treated with different photOperiods and concentrations of NAA, various amounts of roots were produced, Tables VIII and IX. After transplant- ing, the different photOperiods and concentrations of NAA also affected subsequent root and top growth. When tomato stems were air-layered for two and three weeks under a normal day length and treated with 10 p.p.m. NAA, rooting occurred and was more pronounced when air-layered for three weeks, Figure 7. Tomato stems air-layered for two and three weeks with 100 p.p.m. NAA and placed under a normal day length developed only short, stubby roots or root initials. 32. .pcospeonu some 2H mmawpvso a scam enmeapmo o>fipoono2m m mm: cowpmauom soon mo acumen .H no. mo. mo. mo.ooa ho. mo.ooH mo. no. mo.ooa mo. mo. mo. msosnwaeoo \ Re. no. mo. mo.ooa mo. wa.ooa mo. mo. mo.ooa mo. mo. no. npmnuq use awaken semen as“ amuHAI,uHmaaacH a>mom -euz pace use: seem new: seem “satoaoaoaa .e...m4m..oi3. Jmlmlle . 3. 33:8 .owno N sewage“: .ocaaeoo .me> assvsoasomo acowmuomoowq Ho muoheHIha< xoozloza mo Hmoflomshom poem :0 <42 Mo meowpmhpceocou escape> use meownomoponm aceaomuwo mo vacuum HHH> mqm .65.. use? .03 cooamnmmooflm mo 30375 xevzWoouse mo decapmfiom poox so <42 no acowoeapcoocoo msofing pee mvowaomouozm ups-nomad Ho 903mm NH BBQ. 3h. Figure 7. Moderate root formation of chopgrsicon esculentum, var. can-me, Michigan I Ohio, when air-layered with 10 p.p.m. NAA under a normal day length for two weeks. Figure 8. Heavy root formation of geomreicon esggentum, var. call-lane, Michigan I Ohio, when air-layered for two weeks under a normal day length and without NM. 35- 30. Tomato stems air-layered for two and three weeks and placed under a normal day-length without an application of NAA produced a heavy formation of roots, Figure 8. It was also noticed that the sphag- num moss of these air-layers was dry when the air-layers were removed, thus indicating that newly formed roots are proficient in uptake of water. Air-layering of tomato plants for two and three weeks under a continuous photOperiod and with different concentrations of NAA produced similar results as when other tomato plants were air-layered under a normal day length with the same oonc entrations of NAA, Tables VIII and IX. As all two and trree-week air-layers that had not been treated with NAA produced a heavier root formation than air-layers that had been treated with NAA, this served to emphasize the fact that plants respond differertly when treated with a root inducing hormone. Symptoms of physiological disturbance appeared on leaves of tomato plants three days after the air-layers were applied to the stems of the tomato plants. Symptoms first appeared as small necrotic spots on various leaflets of the leaf followed by chlorosis and complete wilting of the leaflet affected. Symptoms usually appeared on the second and third leaf above the girdled area and in a few cases, also appeared on the first, fourth and fifth leaf above the girdled area. Symptoms appeared in 13.6% of the plants that were not treated with NAA and placed under a normal day-length and again in 13.6% of plants that were not treated with NAA and.placed.under a continuous photoperiod. None of the plants treated with 10 p.p.m. NAA were affected. With plants that were air- 37. layered with 100 p.p.m. NAA, symptoms appeared in 64.3% of plants that were under a normal day-length and in 92.8% of plants that were under a continuous photoperiod. It was thought that these symptoms may be signs of a nutrient deficiency due to scoring as the plants had previously produced signs of a nitrogen deficiency. Thus, three plants of the same variety and age were scored in the previously described manner, but no air-layer was applied; symptoms did not appear. Three additional plants were air-layered with 100 p.p.m. NAA and again symptoms appeared. Cause of'the damage that developed from air-layering remains unexplained. However, there were indications that concentrations of NAA at 100 p.p.m. will accentuate the symptoms while NAA at 10 p.p.m. may, in sane way, compensate or offset occurrence of'symptoms. Four weeks after two and three-week air-layers were transplanted, the different air-layering treatments produced different amounts of top growth, Tables X and XI and Figure 9. Variations in t0p growth produced by two-week air-layers under different photoperiods and NAA treatments indicated that a combination of a long photoperiod with NAA in a low concentration, such as 10 p.p.m. will produce a physiological effect on axillary buds causing them to sprout and grow at a faster rate than normal. Four weeks after transplanting, 50% of'the two-week air-layers treated with 100 p.p.m. NAA and placed under a normal and continuous photoperiod were Just beginning to produce top growth while the remain- ing plants were dead or dying. An examination of these plants revealed that the stem of the cutting in vicinity of the notched area had deteriorated and root formation and growth was taking place above and 38. .anoagmoup Some ad mmcfippso b so ocean pcMHo: owmao>< .H o. «.3 0.3 o. .023 mod .. :3 o. méa 0.2 o. m.m ma .. 2m 0. O.¢ o.m o. O.m m.¢ 2003 now .35 32a .3303. manage a 33:» uewaoom a lacH poem eueaoooz z>eor nficH poo: oomaoooz h>eom mafipamaancmas .sdd 8H .sdd 3 33:8 .add ooa .add oa aoaoeoo no»: 333 pnqu mooscaacoo smmcoq wen Hmanoz eafia as a mouse mo.oo« paeuvnse .2. -;w:iq 1? .upoHAoaouozm uaohomman one «<2 mo mcofipeaosooeoo anomams new; consume who: owns muoaeauaw< xoeznoza Mo mcflocmanmnmaa Aopm< .oano x comanoflz aocsasoo .am> .EduCoHsomo coowmnoQOOhJ mo Hszoau mam Hfikd Ho muoposapcoo ca mamas: omoao>< 1", 11’ N mqmde LO. Figure 9. Top growth of two-week air-layers or agopgrsigog eeggentun, var. consume, Michigan I Ohio, plants in relation to different treatments with NAA two weeks after transplanting. Left , control. Center, 10 p.p.m. NAA. Right, 100 p.p.m. NAA. 1+1. below this area. Four weeks after transplanting, all three-week air—layers treat- ed with 100 p. p.m. NAA and placed under a normal and continuous photo- period produced two centimeters of top growth. An examination of these plants revealed that the stems had not deteriorated and that a moderate amount of roots was present. Three-week air-layers that were grown under a normal photoperiod and were not treated with NAA produced about four centimeters more top growth four weeks after transplanting than did two-week air-layers grown under a normal photOperiod and not treated with NAA. Four weeks after transplanting, plants air-layered for three- weeks, treated with 10 p. p.m. of NAA and placed under a normal photo- period produced two centimeters more top growth than did two-week air- layers treated with 10 p.p.m. NAA and placed under a normal photoperiod. However, these three-week air-layers treated with NAA produced less top growth than three-week air-layers that were not treated with NAA. Three-week air-layers under a continuous photoperiod and treat- ed with 10 p.p.m. NAA produced approximately four centimeters less top growth than did two-week air-layers placed under a continuous photoperiod and treated with 10 p.p.m. NAA. Three—week air-layers that received a cmtinuous photoperiod but not treated with NAA also produced approximately three centimeters less t0p growth than did two-week air—layers treated in the same manner. As with two-week air-layers that received a continuous photo- period, four weeks after transplanting, the three-week air-layers treated with 10 p.p.m. and placed under a continuous photoperiod produced approximately three centimeters more tOp growth than did three-week A2. air-layers treated with 10 p.p.m. of NAA and placed under a normal photoperiod. Four weeks after the two and three-week air-layers were trans- planted, the different air-layering treatments produced different amounts of root growth, Tables XII and XIII. All plants that were air-layered for two weeks, except those treated with 100 p.p.m. NAA produced a heavy root growth four weeks after transplanting. Likewise, all plants air-layered for three weeks, except those treated with 100 p.p.m. NAA, produced a heavy root growth four weeks after they were transplanted. However, root growth was of a heavier type in three-week air-layers than in two-week air-layers. Formation of a slightly heavier amount of root growth by plants air- layered for three weeks may be due to a more mature root system.at time of transplanting. AIR-LAYEleG 0F PELAnGUNIUM ZUNALE, VAR. RAUIU RED USING VAnIUUS ULNCENTRATIUNS UF NAA UNDnn DIFFEdENT PHOTOPhdIODS Four weeks after treatment, air-layers that received different concentrations of NAA along with cuttings placed in sand produced dif- ferent amounts of root formation, Table XIV. 0f cuttings placed in sand under a normal photoperiod, 20% rooted while another 13% were dead or dying. An examination of dead and dying plants revealed that the portion of the plant that had been placed.in sand had rotted away. Forty percent of the plants not treated with NAA and grown under a normal photoperiod produced roots while another 20% were dead or dying. All dead or dying plants revealed the same symptoms upon examination; 43- ..Eospooup some 5 madman N. no 95533 2,300de a mm: 2.30% noon Ho oeHMoo .H mo. No.03 no.9: mo. ”8.03 “0.03 Sum mm, . mm mo . «no . mm 12 no . fio . 5:32 mi: mo. mo. Exam mo. mo. afifl .sdé OOH .sdd OH Houpcoo .Edd ooa .adé 3 H9580 $230.6 poom mo oak“. .E 3 moosfiuuoo 3 e3 an 3502 635.3389 one: .030 N 53:3: .3338 33> .5533: mlllldmulhv cows." 00 A no meothLfis. xooZIoosca .334. 3303 noon 29:96 noom emopcoouom .HHN canon. .auoapmoup some cw madman b we oamfiapmo e>aooonnsm m mm: npzoum poop no oonwea .H lull: If. |il|lI|l| mo. $0.03 $0.03 mo. $0.03 $0.03 bio: $0.0m *0. mo. mmém mo. mo. 53»: no.3 mo. no. undo mo. mo. 9&3 .add 03 .add 2 H238 .sdd 02 .add 3 33:8 Message seem so :5. 14»: S 38:. .H.a.:__8 333 NS. Hafiioz assigns“. 883 .335 N cemflofi‘ 32.2550 38> .5233? leoowwdomooHA mo muohaaahsx xoozuoza so»: 8303 .Bom 20396 poem owevcoonom HHHx 35.9 45. .ucosuoouo some CH mmcwppzo m «o epdfiapmo e>Hpoonnsm o no: :ofipmewofi goon mo nonwon .H fl “0.00H m0. m0. no. mo. .a.a.a 00H names no.0; &0. mo. *0.00 no. .fi.n.a OH mdosuapuoo mo.om $0. $0.00 mo. mo.om Hohaeoo ROeOOH RC. $0 R0. R00 eaonmenm OOH “Oeom “be mo. R00 mOeON eaeQeQ OH .333 no.0m ea. $0.04 «0. £0.04 Hospcoo sun Haanoz Rm.ma $5.0 mo. mm.ma Mu.oo 02mm cw sweaspso vmoa mfiopm weapoom MGHpOOfi wdfipoom vthom macaw on h>aoz oumuoooz gamma maoos oz acusumona unoapaoue uanA >Hx.dqm new moowhonopocm pconoMMwQ H0 poommm 1.6. a progressive chlorosis of the leaves starting from where the air— layer was applied and progressing to the apical portion of the stem. The portion of the stem where the airblayer was applied had deteriorated as had the basal portions of the cuttings that were placed in sand. As deterioration of the stems occurred with the cuttings placed in sand and also in the air-layers that were not treated with NAA, the immediate cause was probably due to pathogens and a high.mpisture con- tent while concentrations of NAA from low to high accentuated the deterioration. Though 20% of air-layers not treated with NAA and grown under a continuous photOperiod were dead or dying, 60% formed roots. 0f the air-layers that were treated with 10 p.p.m. NAA, 60% formed roots, while AO% of the plants were dead or dying. All plants treated with 100 p.p.m. NAA were dead or dying four weeks after air-layering. Symptoms of dead or dying plants were the same as previously described. Where root formation had taken place the Sphagnum.moss was in a dry condition while the moss was still very moist in air-layers where there was no root formation. This experiment indicated that a longer day-length probably caused a faster t0p growth thus giving rise to faster root formation which undoubtedly caused the sphagnum.moss to dry out. This would indi- cate, that with some plants, it would be best to air-layer in Spring or summer when days are longer or when the plant is making maximum growth. L7. AIRPLAdeING OF LYCOPEHSICON ESCULnNTUM, VAR. COMMUNE, SPARTAN HYBRID WITH VARIOUS CONCENTdATIONS OF MALEIC HYDRAZIDE Two weeks after treatment, the air-layers that were not treated with maleic hydrazide produced the greatest amount of root growth, Table XV, Figure 10. Air-layers that were treated with 5 p.p.m. maleic hydrazide developed a moderate amount of root growth while air- layers that were treated with 50 p.p.m. maleic hydrazide produced very short roots or root initials. Though maleic hydrazide tended to inhibit root growth, it did not prevent the formation of roots. Figure 10. Root formation and growth of Air-layers of chomrsicon esflegtun, var. counune, Spartan Hybrid, in relation to treatment with maleic hydrazide. Left, 5 p.p.m. maleic hydrazine. Right, control. . *T‘TJI‘I "‘ "my" " I . _='—. L9. .phmapmouu some ca mueeda a Mo cassava» ebwpoonnnm 0 mm: npzoum poop H0 undead 029 .H no. ac. no.3. no.3 .32 R as. mass 8...? mo. .add n 3.3 mm :3 mo. m0. H2200 030: unwise»: Emfl has naefiaficH pooz acoapeoha H5296 s8: .3 one“ one on soaaaaa one; .0fiunh: cepnoam .ocsssoo .sm> .sdpnoH0000 newsman»: awoamz H0 mcofiueapnoocoo meowam> : 5N.mqm