Translocation and Metabolism of Injected Maleic Hydrazide in Silver Maple and American Sycamore Seedlings

Studies were conducted to determine the fate of ¹⁴C-maleic hydrazide injected into the stem xylem of 1-year-old silver maple (Acer saccharinum L.) and American sycamore (Platanus occidentalis L.) seedlings. Maleic hydrazide was found to translocate to all parts of the plant within 1 day after treatment. The autoradiographs indicated that the radioactivity was accumulated in meristematic regions of the leaves. A significant amount (over 15% of the applied ¹⁴C) was exuded out of the roots into the nutrient solution after 30 days. The ¹⁴C in the nutrient solution was in the form of unchanged maleic hydrazide, whereas in plant tissue a metabolite possibly a conjugate with sugar was formed. With the passage of time, the amount of metabolite seemed to increase in proportion to that of maleic hydrazide. Approximately 30% of the applied ¹⁴C was unextractable with methanol after 30 days.     

Kinetin Transport to Axillary Buds of Dwarf Pea (Pisum sativum L.)

Decapitation resulted in the transport of significant amountsof ¹⁴C to the axillary buds from either point of application,but pretreatment of the cut internode surface of decapitatedplants with IAA (alone or in combination with unlabelled kinetin)inhibited the transport of label to the axillary buds and resultedin its accumulation in the IAA-treated region of the stem. Inintact plants to which labelled kinetin was applied to the apicalbud there was little movement of ¹⁴C beyond the internode subtendingthis bud; when labelled kinetin was applied to the roots ofintact plants, ¹⁴C accumulated in the stem and apical bud butwas not transported to the axillary buds. A considerable proportionof the applied radioactivity became incorporated into ethanol-insoluble/NaOH-solublecompounds in the apical bud of intact plants, in internodestreated with IAA, and in axillary buds released from dominanceby removal of the apical bud. The results are discussed in relation to the possible role ofhormone-directed transport of cytokinins m the regulation ofaxillary bud growth.     

The effect of growth substances on Verticillium wilt of tomato plants

This paper describes the effects of a number of growth-regulating substances on the development of disease in tomato plants caused by Verticillium albo-atrum. Indole-acetic acid usually reduced disease and also reduced the number of hyphae in the stem but it increased tylosis; low concentrations slightly stimulated disease development. Some control of disease was obtained by removing apical buds, and axillary shoots as they developed. When the apical bud alone was removed, developing axillary shoots sometimes wilted; this did not occur in plants with intact buds. Gibberellic acid increased disease in susceptible plants and also induced symptoms in resistant plants. Maleic hydrazide greatly reduced growth of plants, made them more diseased and stimulated growth of the parasite in the vessels. Of other growth-regulating substances tested, 2,4,6-trichlorophenoxy-acetic acid, 2,3,5-triiodobenzoic acid and 2,4-dichlorophenoxyacetic acid increased disease at some concentrations and reduced it at others. Cycocel (2-chloroethyl) trimethyl ammonium chloride and naphthaleneacetamide, gave good control of disease over a range of concentrations when applied to the soil in which plants were growing. Treatments which reduced disease also reduced the growth of the parasite in the shoot and stimulated the formation of tyloses. Indole and 2,4-dichloroanisole had some effect on disease development but this was much less than that induced by the other substances.     

Effects of waterlogging on chickpeas II. Possible causes of decreased tolerance of waterlogging at flowering

Waterlogging tolerance of chickpeas was found, in earlier work, to decrease sharply at flowering. Three experiments were performed to attempt to explain the mechanisms involved in this response. In the first, a range of treatments was imposed to modify the plant's source/sink relationships, as carbohydrate supply and partitioning were considered possible determinants of waterlogging tolerance. Plants from which buds were removed showed the most rapid recovery after waterlogging. Defoliation immediately before waterlogging reduced the rate of recovery. Application of benzyladenine plus gibberellic acid prior to waterlogging delayed stomatal closure and leaf senescence, inhibited apical growth and stimulated axillary growth. The second experiment aimed to confirm the influence of bud removal and to determine whether waterlogging tolerance is correlated with carbohydrate supply. Treatments comprised two sowing times, ten days apart, and two bud treatments (retained and removed). Waterlogging was imposed when older plants had been flowering for seven days and younger plants were in bud. Waterlogging caused soluble sugars to accumulate in the lower stem, suggesting that a deficiency of assimilates did not contribute to waterlogging injury. Similarly, waterlogging increased nitrogen concentration in the stem, through mobilisation from senescing leaves. Bud removal enhanced leaf survival and reduced mortality rate after waterlogging; it also increased starch concentration in the lower stem, indicating that storage of assimilates decreased in flowering plants. However, across all treatments, starch concentration was not correlated with waterlogging tolerance. In the third experiment, the effect of the senescence-promoting factor ethylene on preflowering and flowering plants was assessed, using the ethylene-releasing agent ethephon. Ethephon reduced growth to a slightly greater extent when applied prior to flowering than at flowering. There was no evidence that inadequate supply of carbohydrates or nitrogen in the stem, or increased sensitivity to ethylene, contributed to waterlogging intolerance in flowering chickpea plants.     

Distribution of labelled auxin and derivatives in stem tissues of intact and decapitated broad-bean plants in relation to apical dominance

[³H]-auxin (0.13 to 0.18 nmol) was applied to the apical bud of broadbean plants (Vicia faba L. cv. Aguadulce). After 24 h, the exportation from the donor organ was ended. After 48 h, i.e. 10–15 h after the passage of the [³H]-auxin pulse into the root system, the distribution and the nature of labelled molecules located in the basal part of the stem and in the axillary buds were investigated. Chromatographic analyses concerned both intact plants and plants decapitated 12 h, 24 h or 42 h after the [³H]-auxin application. In intact plants, there was no significant amount of [³H]-auxin in the axillary buds, whose radioactivity was very low compared to the stem tissues. The labelled molecules with the Rf of auxin represented 50% or more of the whole radioactivity of the stem tissues. The distribution of [³H]-auxin was not uniform along the stem. In particular, the cotyledonary node zone, bearing the most inhibited buds, which is known to be an important centre of label retention, contained the highest amounts of labelled auxin both in intact and decapitated plants. The decapitation was quickly followed by a decrease of the [³H]-auxin amount in the stem base more than 15 cm away from the wound, particularly in the scale leaf nodes, whose axillary buds were mainly the ones to grow after relief from apical dominance. The induction of this early decrease was clearly distinct in plants decapitated when auxin exportation from the donor organ was ended.     

Lateral Bud Growth in Phaseolus vulgaris L. and the Levels of Ethylene in the Bud and Adjacent Tissue

Ethephon and the ethylene inhibitors Ag⁺ and aminoethoxyvinylglycine (AVG) inhibited outgrowth of the axillary bud of thefirst trifoliate leaf in decapitated plants of Phaseolus vulgaris.Endogenous ethylene levels decreased in the stem upon decapitationalthough it is not conclusive that a causal relationship existsbetween this decrease and the release of axillary buds frominhibition. The proposition that auxin-induced ethylene is responsiblefor the suppression of axillary bud growth in the decapitatedplant when the apical shoot is replaced by auxin is not borneout in this study. Application of IAA directly to the axillarybud of intact plants gave rise to a transient increase in budgrowth. This growth increment was annulled when AVG was suppliedwith IAA to the bud despite the fact that the dosage of AVGused did not affect the normal slow growth rate of the bud ofthe intact plant or bud outgrowth resulting from shoot decapitation.     

The Development of Embryo, Endosperm, and Nucellus Tissues in Relation to Receptacle Growth in the Strawberry

Maleic hydrazide was applied to strawberry plants in an attemptto inhibit the growth of specific tissues within the developingachenes so as to trace their function as sources of stimulito the developing receptacles. Whole plants were sprayed at 1, 500 p.p.m. at various intervalsbefore and after the opening of the primary flower on the truss.Regular twice weekly sprays with various concentrations of 2-naphthoxyaceticacid at concentrations between 50 and 5oop.p.m. were also combinedwith the maleic hydrazide treatments. Observations were madeon the development and final weight of all fruits, and valuesobtained for the percentages of achenes in which there wereviable embryos at maturity. Achenes treated with maleic hydrazideat various intervals were examined to determine the effectsof the treatment on the development of the embryo, endosperm,and nucellus. If treatment with maleic hydrazide was delayeduntil the third day after anthesis the receptacles were ableto develop and to ripen successfully even though all the acheneson their surface were devoid of viable embryos. Maleic hydrazideat 1, 500 p.p.m. was totally inactive as an inhibitor of receptacleexpansion if treatment was delayed till later than the 10thday after anthesis. It is concluded that the embryo is not the source of the growthstimulus which promotes the development of the receptacle, andthat the endosperm probably does not become active as a majorsource of auxin-like substances until it has become cellularbetween 10 and 14 days after anthesis. The possible identityof the tissue controlling receptacle-growth in the period immediatelyfollowing pollination and fertilization is discussed.     

Effects of exogenous cytokinins on flowering of the short-day plantChenopodium rubrum L.

Kinetin at a concentration from 3.10^-6 M to 1.10^-3 M was applied to the plumule ofChenopodium rubrum plants during photoperiodic induction. Different levels of induction were compared (one and three short days). The higher concentrations of kinetin applied to induced plants inhibited flower formation. The rate of leaf initiation was increased under these treatments. Lower concentrations of kinetin (from 3.10^-6 M to 1.10^-5 M) usually promoted lateral bud formation and flowering. The step-wise application of kinetin revealed that the inhibitory effect on flowering had been restricted to the inductive period. The effects of kinetin, benzyladenine and trans-zeatin were compared in plants partially induced by two short days. High concentrations always inhibited flowering. Benzyladenine was the most effective in this respect. Root removal diminished the inhibitory effects of cytokinins on flowering as was stated with benzyladenine. It is assumed that endogenous cytokinins play a role in the regulation of organogenetic activity of the stem apical meristem. Depending on the photoperiodic conditions, they presumably exert their activity by maintaining the vegetative functions of the apex.     

Regrowth of spring canola (Brassica napus) after defoliation

Aims

Regrowth of dual-purpose canola after grazing is important for commercial success and the aim of this research was to investigate the effects of defoliation on the development, growth, photosynthesis and allocation of carbohydrates.

Methods

We conducted two pot experiments in which defoliation was conducted at multiple intensities with scissors. Experiment 1 determined changes in flowering date due to defoliation while Experiment 2 investigated the effects of defoliation on growth, photosynthesis and allocation of carbohydrates in canola.

Results

Time to the appearance of the first flower was delayed by up to 9 days after the removal of all leaves at the start of stem elongation (GS30), and up to 19 days if the elongating bud was also removed. Stem growth rate decreased by 56–86 % due to defoliation and tap roots did not increase in mass when plants were completely defoliated. Leaf area continued to expand at the same rate as in un-defoliated plants. The new leaf area established per gram of regrowth biomass over 20 days was 158 cm².g^-1 for the complete defoliation treatments compared with 27 cm².g^?1 for the half-defoliated treatment and 13 cm².g^?1 for the un-defoliated treatment. Despite a reduction in total biomass of up to 60 %, the proportion of dry matter partitioned to the leaves was 18 % for all treatments within 20 days after defoliation. Total non-structural carbohydrate levels were reduced rapidly in the stem by day two (predominately sucrose) and the tap root by day four (predominately starch) after defoliation and did not recover to match un-defoliated plant levels within 20 days. Residual leaves on defoliated plants maintained photosynthetic rate compared with the same leaf cohorts on un-defoliated plants in which photosynthetic rate decreased to 39 % by day 12.

Conclusions

The rapid recovery of leaf area in defoliated canola was facilitated by the sustained high photosynthetic rate in remaining leaves, rapid mobilisation of stored sugars (stem) and starch (root), and a cessation of root and stem growth.     

The transport of radiolabeled indoleacetic acid and its conjugates in nodal stem segments of Phaseolus vulgaris L.

The transport of radiolabeled indoleacetic acid (IAA), and some of its conjugates, was investigated in nodal stem segments of Phaseolus vulgaris L. Donor agar blocks containing either [2-acetyl-¹⁴C]-IAA; [2-acetyl-¹⁴C]-indole-3-acetyl-L-aspartate (IAAsp); [2-acetyl-¹⁴C]-indole-3-acetyl-L-glycine (IAGly); or [2-acetyl-¹⁴C]-indole-3-acetyl-L-alanine (IAAla) were placed on either the apical or basal cut surface of stem segments each bearing an axillary bud at the midline. In some experiments, a receiver block was placed on the end opposite to the donor. After transport was terminated, the segments were divided into five equal sections plus the bud, and the radioactivity of donors, receivers and each part of the stem segment was counted.For all four substances tested, the amount of ¹⁴C transported to the axillary bud from the base was the same or greater than that from the apical end. After basipetal transport, the distribution of ¹⁴C in the segment declined sharply from apex to base. The inverse was true for acropetal transport. Transport for the three IAA conjugates did not differ substantially from each other.The IAA transport inhibitor, N-1-naphthylphthalamic acid (NPA), inhibited basipetal ¹⁴C-IAA transport to the base of the stem segment but did not alter substantially the amount of ¹⁴C-IAA recovered from the bud. Transport of ¹⁴C-IAA from the apical end to all parts of the stem segment declined when the base of the section was treated with nonradioactive IAA. Taken together with data presented in the accompanying article [Tamas et al. (1989) Plant Growth Regul 8: 165–183], these results suggest that the transport of IAA plays a role in axillary bud growth regulation, but its effect does not depend on the accumulation of IAA in the axillary bud itself.     

Effect of Severity of Defoliation on the Viability of Reproductive and Vegetative Axillary Buds of Trifolium repens L.

This glasshouse experiment was performed to assess the effectsof a range of constant defoliation regimes applied to cuttingsof a single large-leaved genotype ofTrifolium repens L. on theviability of its axillary buds. Plants were established to comprisea single main stolon (axillary branches were removed) and defoliationtreatments were applied by removing the older (basal) leavesuntil leaf complements of 1·0, 1·5, 2·0,2·5, 3·0 or all leaves (control) remained. Basalleaves were subsequently removed as necessary to maintain thetarget leaf complements. Only severe defoliation (leaf complements of 1·0 and1·5) induced a loss of viability in axillary buds. Lossof viability was greatest in reproductive buds present withinthe apical bud when the treatments were first imposed. Althoughthe most severe treatment (leaf complement 1·0) resultedin death of half the plants, in plants surviving that treatment,death of vegetative axillary buds was restricted to 21% of thevegetative buds at the three youngest node positions withinthe apical bud at the time of treatment application. No othertreatment induced any loss of viability of vegetative buds.There was no loss of viability of axillary buds at nodes formedafter the treatments were imposed. The frequency of initiationof inflorescences at nodes formed after treatments were imposeddecreased as defoliation severity increased. Severe defoliation resulted in marked changes in plant morphologyindicative of a sharp decrease in availability of intraplantresources. It was concluded that under severe defoliation: (1)the potential for vegetative growth (as represented by viablevegetative axillary buds) was maintained at the expense of reproductivegrowth; and (2) that the loss of viability of axillary budswas associated with the sudden changes in physiological processesinduced by defoliation as there was no loss of viability inbuds formed after plants had adjusted their phenotype to oneof smaller size. Trifolium repens L.; white clover; defoliation; axillary buds; viability; inflorescences     

Effect of Defoliation or Excision of Growing Axillary Shoots on the Composition of Labeled Products of Photosynthesis in the Leaves and Xylem Sap of Kidney Bean

The content of ¹⁴C in the products of photosynthesis of the source leaf and xylem sap was investigated in kidney bean (Phaseolus vulgaris L.) plants during the stage of mass tillering. ¹⁴C partition was measured a day after two-minute photoassimilation of ¹⁴CO₂ by an individual mature leaf located in the middle part of the shoot. The source-sink relations were disturbed by the excision of all mature leaves (except the source leaf) or all growing axillary shoots. The leaves or growing axillary shoots were excised 15 min after leaf feeding with ¹⁴C₂. A day later, in plants with excised growing axillary shoots, the content of ¹⁴C in the source leaf was by 18% higher and in those with removed leaves by 15% lower than in control plants. The next day after the excision of growing axillary shoots, radioactivity of the xylem sap increased; after defoliation, both the volume of the xylem sap and its specific radioactivity decreased. In the xylem sap of defoliated plants, the proportion of ¹⁴C in malate decreased more than six times, whereas the proportion of ¹⁴C in amino acids somewhat increased (1.5 times). In two days, the volume of the xylem sap exuded by treated plants became the same as in control plants and its radioactivity decreased almost by an order of magnitude but essentially did not differ in the both types of treatment. It is concluded that the processes occurring in the roots are governed by photosynthesis but its regulatory effect is limited by a photoperiod and largely depends on changes in the ratio between biosynthesis of amino acids in the roots and leaves.__________Translated from Fiziologiya Rastenii, Vol. 52, No. 4, 2005, pp. 518–521.Original Russian Text Copyright © 2005 by Chikov, Bakirova, Batasheva, Sergeeva.     

Changes in the rhizosphere microflora of maize seedlings by pretreatment of roots with hormones and urea

Summary Effect of pretreatment of root of maize seedlings with gibberellic acid, maleic hydrazide and urea was investigated. Gibberellic acid at 1 ppm stimulated the growth of fungi, bacteria, and actinomycetes in the rhizosphere region of maize seedlings while at 5 ppm concentration population of bacteria and actinomycetes were suppressed. Maleic hydrazide treatment stimulated all the three groups at 5 ppm concentration but at 1 ppm there was increase in population of only fungi and actinomycetes. Urea stimulated the growth of fungi, bacteria, and actinomycetes. The order of predominance of different groups also changed with treatments. It was fungi > bacteria > actinomycetes in case of gibberellic acid at 1 ppm and 5 ppm and maleic hydrazide at 1 ppm; and bacteria > fungi > actinomycetes in case of maleic hydrazide at 5 ppm, urea at 0.1M and in control.     

Cells within the nodal region of carnation shoots exhibit a high potential for adventitious shoot formation

Adventitious shoot formation was studied with leaf, stem and axillary bud explants of carnation (Dianthus caryophyllus L.). The shoot regeneration procedures were applicable for a wide range of cultivars and shoot regeneration percentages were high for all explant types. Using axillary bud explants, shoot regeneration efficiency was independent of the size of the bud and of its original position in the plant. In contrast, shoot regeneration from stem and leaf explants was strongly dependent on their original position on the plant. The most distal explants (just below the apex) showed the highest level of shoot regeneration. The adventitious shoot primordia developed at the periphery of the stem segment and at the base of leaf explants. In axillary bud, stem and leaf explants, shoot regeneration originated from node cells, located at the transition area between leaf and stem tissue. Moreover, a gradient in shoot regeneration response was observed, increasing towards the apical meristem.Abbreviations BA benzyladenine - NAA naphthaleneacetic acid     

Effect of auxin on the elongation of lateral buds and32P accumulation in 2-leaf decapitated pea seedlings

The effect of short and long term auxin treatments on the elongation of axillary buds and³²P accumulation were studied in 2-leaf decapitated Alaska pea sailings. It was found that (1) auxin delayed the elongation of the lateral buds, (2) none of the auxin concentration applied completely inhibited the elongation of axillary buds, (3) auxin had no retarding effect on the growing buds, (4) strong polarization of 32P occurred in the parts above the treated leaf, when auxin was applied for a short period just after decapitation, (5) long term auxin treatments did not induce any such polarization of 32P to the parts above the treated leaf, (6) the root acted as an alternate accumulating organ for 32P when the apex was removed and the buds were inhibited, and (7) in decapitated plants the growing buds polarized 32P.     

Correlative inhibition of lateral bud growth in Phaseolus vulgaris L. timing of bud growth following decapitation

Summary On intact, 3-week-old plants of Phaseolus the larger bud in the axils of the primary leaves shows slow, continuous elongation growth. Release from correlative inhibition can be detected within 30 min following decapitation. When 0.1% indoleacetic acid in lanolin is applied to the decapitated stem stump, the lateral bud shows slow growth during the first 7 h, then stops completely for a further 15 h but after 2 days a further gradual increase in length is observed.The movement of ¹⁴C-labelled assimilates from the subtending primary leaf into the lateral bud increases following removal of the shoot apex. When indole acetic acid is applied to decapitated plants the ability of the buds to import ¹⁴C increases for 5–7 h and then declines to a negligible amount. Little or no radioactivity from tritiated indoleacetic acid is transported into the lateral buds of decapitated plants during the first 48 h following removal of the apex and it appears that rapid metabolism of the compound occurs in the stem tissues.     

Estimation of mutagenicity and metabolic activation after recurrent exposures ofnicotiana tabacum L. var.xanthi to 14 pesticides

Recurrent application (17 administrations in 38 days) of 14 pesticides (Karathane FN 57, Fundazol 50 WP, Dithane M 45, Topsin M 70 WP, Perozin 75 B, Fademorf EK 20, Novozir MN 80, Metation E 50, Pirimor DP, Decemtion EK 20, Zeazin 50 DP, Fatex EK 80, maleic hydrazide and Ethrel) did not increase (with the exception of maleic hydrazide) the frequency of somatic mutations in a heterozygous chlorophyll mutant ofNicotiana tabacumL. var.xanthi n. c. None of the four tested pesticides (Fademorf EK 20, Decemtion EK 20, maleic hydrazide and Ethrel) were transformed in tobacco plants to a stable mutagenic or promutagenic product active in theSalmonella (Ames) mutagenicity assay.     

Acclimation to High CO(2) in Monoecious Cucumbers : I. Vegetative and Reproductive Growth

CO₂ concentrations of 1000 compared to 350 microliters per liter in controlled environment chambers did not increase total fruit weight or number in a monoecious cucumber (Cucumis sativus L. cv Chipper) nor did it increase biomass, leaf area, or relative growth rates beyond the first 16 days after seeding. Average fruit weight was slightly, but not significantly greater in the 1000 microliters per liter CO₂ treatment because fruit numbers were changed more than total weight. Plants grown at 1000 and 350 microliters per liter CO₂ were similar in distribution of dry matter and leaf area between mainstem, axillary, and subaxillary branches. Early flower production was greater in 1000 microliters per liter plants. Subsequent flower numbers were either lower in enriched plants or similar in the two treatments, except for the harvest at fruiting when enriched plants produced many more male flowers than the 350 microliters per liter treatments.     

The effects of gibberellic acid and nutrient sprays on growth and yield of brussels sprout

Young plants of brussels sprout, cv. Cambridge Special, growing in pots in a glasshouse, were sprayed on ten occasions with gibberellic acid (GA) at 0, 25, 100 and 400 p.p.m. and ammonium nitrate (NH₄NO₃) at 0, 0·0125, 0·025 and 0·05 M concentrations in all combinations. In 24 days both GA and NH₄NO₃ increased leaf area, leaf number, dry weights of leaf, stem and root, and fresh weights of leaf and stem. GA increased stem height and decreased fresh weight/unit leaf area (leaf thickness), whereas NH₄NO₃ did not affect stem height and increased leaf thickness. Of the GA treatments, 100 p.p.m. gave the largest plants as judged by fresh weight of the whole plant and leaf area, and of the N treatments 0·05 M NH₄NO₃ increased growth most. The best treatment combination was 0·05 M NH₄NO₃ with 100 p.p.m. GA, which gave the greatest fresh and dry weights of the whole plant, leaf area and leaf dry weight as well as increasing leaf thickness. Significant interactions were found between GA and N for dry weight of leaf, fresh and dry weight of root, and leaf thickness but not for leaf area or stem growth (fresh weight, dry weight, height). The combination of levels of GA and N that can be expected to increase leaf area, leaf dry weight and leaf thickness simultaneously, may lie within narrow limits for a particular crop. In a second experiment plants were sprayed with all combinations of GA (0 and 100 p.p.m.) seven times under glass in pots and ten times in the field, and three levels of KH₂PO₄ on twelve occasions in the field. Sprouts (axillary buds) were harvested in October and February. At the first harvest GA did not affect fresh weight or number, but increased both the total number of sprouts picked (with GA = 80·7; without GA = 69·8 per plant) and the total fresh weight of saleable sprouts (with GA = 2·59; without GA = 2·33 lb/plant). KH₂PO₄ also increased the weight and number of sprouts at the final harvest and the number of small sprouts at the first. There were interactions between GA and KH₂PO₄ (P= < 0·001) for both tota weight and number of saleable sprouts.     

On the role of exogenous gibberellin and cytokinin in the correlation between the leaf and its axillary bud in hortensia (Hydrangea opuloides C. KOCH)

The role of exogenously supplied gibberellin (GA₃) and cytokinin (benzyladenin -BA) in the correlation between the mature leaf and its axillary bud was investigated in one-node segments ofHydrangea. When both leaves were left on the segments, then both GA and BA were able to determine the dominance between axillary buds, that means that the bud treated with the corresponding growth regulator grew more vigorously. When one of the leaves was removed, the bud belonging to the removed leaf grew more vigorously, but GA applied onto the axillary bud belonging to the remaining leaf caused a complete correlation reversal: the bud belonging to the remaining leaf grew more vigorously. On the contrary, the application of BA onto the bud of the remaining leaf resulted in only insignificantly stimulated growth of the bud belonging to this leaf.