Application Of Chlormequat Chloride Research Articles

Foliar application of chlormequat chloride improves lodging resistance and grain yield in bread wheat

Foliar application of chlormequat chloride improves lodging resistance and grain yield in bread wheat

Productivity and Morpho-phenological Characters of Pigeonpea [Cajanus cajan (L.) Millsp.] as Influenced by Crop Geometry and Nipping Practice

Background: One of the possible agronomic ways for increasing productivity of pigeonpea is adoption of suitable crop geometry with nipping practices for getting suitable crop architecture for optimum utilization of resources. This investigation was planned to study the influence of crop geometry and nipping practices on production potential of pigeonpea. Methods: The field experiment was conducted at experimental farm of the Department of Pulses, TNAU, Coimbatore, during kharif season of 2021 and 2022. The experiment was laid out in split plot design with each four main and sub plot treatments. The main plot treatments comprised of four crop geometries while thesub plot treatments were nipping practices which includes no nipping, mechanical nipping and chemical nipping. Result: Various crop geometries shown remarkable effect on growth and development of pigeonpea. The crop geometry of 90 cm ´ 30 cm and 90 cm ´ 45 cm recorded maximum plant height of pigeonpea as compared to other wider crop geometries. While in case of all the other growth attributes viz. number of functional leaves per plant, leaf area, number of branches per plant and dry matter accumulation per plant crop geometry of 120 cm ´ 45 cm and 120 cm ´ 30 cm were found superior as compared to othertreatments and were at par with each other. The yield per hectare was increased at wider crop geometry 120 cm 45 cm as the higher per plant yield was compensated by lesser plant population. The crop geometry 120 cm ´ 45 cm produced significantly higher seed yield (1187, 1275 and 1231 kg ha-1 during 2021, 2022 and pooled mean respectively) over crop geometry of 90 cm ´ 30 cm and crop geometry 90 cm ´ 45 cm, but it was found at par with crop geometry 120 cm ´ 30 cm. Among the nipping practices, growth characters viz., plant height, number of functional leaves, leaf area, number of branches and dry matter accumulation per plant as well as phenological characters were enhanced with the foliar application of chlormequat chloride @500 ppm during both the years of study. Foliar application of chlormequat chloride @ 500 ppm also recorded significantly highest seed yield (1152, 1237and 1195 kg ha-1 during 2021, 2022 and in pooled data, respectively), while it was at par with foliar application of mepiquat chloride @ 500 ppm.

Effect of Chlormequat Chloride Application on Vegetative Growth and Overall Quality of Grape Cultivars Under Protected Cultivation

Effect of Chlormequat Chloride Application on Vegetative Growth and Overall Quality of Grape Cultivars Under Protected Cultivation

INFLUENCE OF RETARDANTS ON MORPHOGENESIS AND ANATOMICAL STRUCTURE OF A LEAF APPARATUS OF WHITE MUSTARD PLANTS

The influence of antigiberrelic preparations on morphogenesis and anatomical structure of a leaf apparatus was studied. It is found that treatment of white mustard plants with chlormequat chloride and follicle caused a decrease in linear size, stem thickening, increase in the number and area of leaves.The influence of growth inhibitors on the mesostructure of white mustard plant leaves (Sinapis alba L.) was investigated. The application of preparations on mustard plantations in the budding phase led to optimization of the leaf anatomical structure, a thickening of the assimilation parenchyma due to the growth of its cells was observed.Under the action of the preparations, the cell volume of the columnar parenchyma in the sample with chlormequat chloride application increased and now is * 2489.86 ± 120.66 μm3, with follicle -2295.36 ± 116.25 μm3, compared to the control sample, where the volume is 2038 ± 101, 92 μm3. At the same time, the cell linear sizes of spongy parenchyma in experimental variants increase. A more expressible effect was observed under the action of chlormequat chloride.Investigation of the effect of synthetic plant growth regulators on the respiratory tract of white mustard leaves reveals that the number of stomata increased in the number of treated plants. The number of stomata in the variant with chlormequat chloride is - 377.79 ± 10.78 μm3, using follicle is * 370.88 ± 12.24 μm3 compared to the control sample of 341.49 ± 12.23 μm3.

Canopy management: the balance between lodging risk and nitrogen use for spring wheat production in the Canadian Prairies

Lodging risk in spring wheat has grown with the introduction of high-yielding cultivars that require high nitrogen (N) inputs to optimize grain yield and protein content. Canopy management (CM) strategies have been used to reduce lodging risk. However, the short growing season and unpredictable moisture supply may limit the use of these strategies in the Canadian Prairies. The objective of this study was to quantify the ability of agronomic practices to modify the early season crop canopy, and hence lodging risk, and to determine how these practices influence N use and final grain N yield. Split-plot field trials were established at four site-years (SYs) in Manitoba to evaluate CM strategies including three plant densities, a split N fertilizer application, and the application of chlormequat chloride (CCC) on canopy size (dry matter (DM) and height at anthesis), N uptake and remobilization, lodging and stalk strength, grain yield, protein, and grain N yield on the cultivar AAC Brandon. Precipitation was low during this study (64%–78% of long-term average (LTA)), resulting in modest yields and low lodging pressure. However, low plant density (PD), split N, and CCC applications all showed potential to reduce lodging risk without reducing grain yield or protein concentration. Split N and plant growth regulator (PGR) applications increased final grain N yield by 11.2% and 2.4%, respectively. Therefore, CM practices have potential in the Canadian Prairies to reduce lodging risk without compromising grain N, but results should be validated in higher precipitation environments and across additional cultivars and growing regions of western Canada.

Effect of Chlormequat Chloride on Vegetative Growth, Photosynthetic Activities, and its Residual Dissipation in Thompson Seedless Grapevines

Chlormequat chloride is one of the important plant growth regulators which is a highly stable gibberellins biosynthesis inhibitor used to inhibit vegetative growth and cell elongation. Considering the importance of plant growth inhibitors, the present investigation was carried out to understand the effect of Chlormequat chloride with its different concentrations on vegetative growth, photosynthetic activities and its residual dissipation in Grapevines at two different locations one at Pune, Maharashtra India and second at Nashik, Maharashtra, India during the year 2018-2019. Chlormequat chloride was applied as a foliar spray, where the whole vines were sprayed at concentration of 500, 1000, 1500, 2000 and 2500 ppm with untreated control as a water spray; as a treatments with different developmental stages Viz 5th, 7th, and 15th leaf stage after foundation pruning. Morphological observations were recorded at 45 days and 90 days after foundation as well as fruit pruning. Application of Chlormequat chloride recorded reduced shoot length and Internodal distance while increased in cane diameters, leaf thickness after both the pruning’s in this investigation Photosynthetic activity, yield per vines and percent fruitfulness had significantly influenced with the application of Chlormequat chloride in grapevines. The dissipation of Chlormequat chloride was stable and indicated a non- linear pattern of degradation. Thus, implied that simple first-order kinetics might not be adequate to explain the dissipation behaviour of Chlormequat chloride in grapes.

Enhancing wheat (Triticum aestivum L.) grain yield and quality by managing lodging with growth regulators under different nutrition levels

This study was conducted to determine the effect of different nutrient levels [No nutrients absolute control, RDF (recommended dose of fertilizer) (N:P:K 150:26.22), 150%RDF (225:39.33), 150%RDF + FYM (Farm Yard Manure) (225:39:33 + 15 t ha−1), & 200%RDF (300:52.44 NPK kg ha−1) and application of growth regulators, i.e., water spray, CCC (chlormequat chloride) 0.2%, tebuconazole (0.1%), and tank-mixed application of chlormequat chloride + tebuconazole at first node and flag leaf stage on growth, lodging, yield, and quality of wheat with three replications. Application of 150%RDF + FYM and 200%RDF recorded significantly higher plant height, dry matter accumulation, and tiller density. Lodging percent and score recorded in 150%RDF + FYM was similar to 200%RDF, but sіgnіfіcаntly higher than оthеr levels. The application of chlormequat chloride + tebuconazole recorded the lowest plant height, lodging percent and lodging score. Application of chlormequat chloride + tebuconazole recorded higher 1000-grain weight and grain yield than control, chlormequat chloride, and tebuconazole. In RDF (N:P:K 150:26.22), exogenous application of chlormequat chloride alone was sufficient to reduce lodging. However, at higher nutrient level of 150%RDF or 150%RDF + FYM, both chlormequat chloride + tebuconazole were most promising for reducing lodging and enhancing the wheat productivity.

Yield and morphological characters as affected by chlormequat chloride application in grape cultivar Punjab macs purple

The present investigation was carried out to evaluate the effect ofgrowth retardant Chlormequat chloride (CCC) on morphological characters of grape cultivar Punjab MACS Purple. The foliar application of Chlormequat chloride (250, 500, 750 and 1000 ppm) was done at five leaf stage while the control vines were sprayed with water only. Observations on vegetative growth were recorded at different growth stages. Maximum dose of Chlormequat chloride was found to be most effective in reducing cane length and internodal length while the same dose resulted in maximum cane diameter. There was reduction in leaf area as well as size while the effect on time of anthesis and trunk girth was less significant. It has been reported that yield and bunch weight was maximum with the application of1000 ppm Chlormequat chloride followed by 700 ppm Chlormequat chloride.

Impact of nutrient management practices and plant growth regulators on growth, productivity and profitability of wheat (Triticum aestivum)

This study was conducted during winter season of 2016-17 and 2017-18 at Rajasthan Agricultural Research Institute, Durgapura, Jaipur to evaluate the effect of nutrient management and growth retardants on wheat (Triticum aestivum L.). Results revealed that the application of 150% RDF+FYM led to higher plant height and dry matter accumulation of wheat at all the growth stages (60 days after sowing (DAS), 90 DAS and at harvest) except at 30 DAS (where it was maximum with 150% RDF). The combined application of Chlormequat Chloride (CCC)+Tebuconazole reduced the plant height of wheat by 4.62, 2.25 and 2.86% (60 DAS), 7.07, 2.24 and 3.05% (90 DAS) and 7.35, 2.76 and 4.11% (at harvest) over water spray, CCC and Tebuconazole alone, respectively. The significantly maximum number of effective tillers (423.42 m-2), spike length (10.66 cm) and test weight (40.32 g) were registered with application of 150% RDF+FYM. The combined spray of CCC+Tebuconazole enhanced the test weight by 7.71%, 2.63 and 2.84% over water spray, CCC and Tebuconazole, respectively. The significantly maximum grain, straw and biomass yield of wheat were recorded with 150% RDF+FYM which were 50.87, 50.31 and 50.56% and 12.26, 15.92% and 14.27% higher over control and 100% RDF, respectively. The grain, straw and biomass yields of wheat due to different growth retardant treatments were found statistically at par. The application of 150% RDF+ FYM increased the gross return by 50.74, 13.10 and 3.83% and mean net returns by 60.56, 12.96 and 3.13% over control, 100% RDF and 150% RDF, respectively. Among growth regulators highest net returns (` 68016) and B:C ratio (1.98) were recorded with combined application of CCC+Tebuconazole. It is concluded that integrated nutrient management using 150% RDF+FYM and combined application of CCC+Tebuconazole can be advocated as sustainable strategy for enhancing productivity and profitability of wheat.

Influence of chlormequat chloride on the formation of a photosynthetic apparatus and productivity of linseed

Application of retardants as anti-gibberelline substances leads to changes in the functioning of donor-acceptor relations in the plant organism and inhibition of the growth processes. Reducing of the assimilates demand for the growth of vegetative organs leads to the accumulation of plastic substances with their redistribution to the formation of seeds and fruits.The purpose of the research was establishing the effect of chlormequat chloride as a retardant permitted in Ukraine on the formation of the leaf apparatus and the productivity of oil flax plants (Linum usitatissimum L.).Materials and methods. Oil flax plants of Debut and Orpheus varieties were once treated with 0.5% water solution chlormequat chloride in the budding phase. Morphological parameters of flax plants were studied every 10 days. The mesostructural organization was determined for leaves of the same age. The total amount of oil in flax seeds was determined by extraction.Result. It was found that chlormequat chloride application led to enhance the thickening of stems of plants. Chlormequat chloride treatment resulted the formation of powerful photosynthetic apparatus. The application of retardant increased the number of leaves per plant and decreased the area of a single leaf. It was found that the application of plant growth regulators led to increase the cells size and volume of palisade chlorenchyma, the chloroplast number and size in palisade and spongy parenchyma. Such changes in the mesostructure measurement of leaves caused increase the net photosynthetic productivity that was the important prerequisite for enhancement of crop production. The flow of assimilates was directed to the development of generative organs – fruits, the number of which increased by the retardant as a result of intensive branching of the stem. It was also noted that the number of seeds per fruit and the weight of a single seed increased under the influence of growth regulator. It was established that the application of retardant stimulated a more intense synthesis of reserve compounds in the seeds and oil content in seeds increased. It was necessary to note that the amount of residual drugs substance in the seeds was significantly lower than the permissible concentrations.Conclusions. So the chlormequat chloride treatment on the linseed during the budding period leads to improve the development of leaf apparatus and formation of fruits, which result the improvement of crop production

Особливості анатомічної будови і функціонування листкового апарату та продуктивність рослин льону олійного за дії хлормекватхлориду

<p><span lang="EN-US">We studied the influence of antigibberellin compound </span><span lang="EN-US">chlormequatchloride<span> on the morphogenesis, functioning of “source-sink” relation system, yield and quality of linseed oil.</span></span><span lang="EN-US"> It was found that </span><span lang="EN-US">chlormequat chloride application led to enhance the </span><span lang="EN-US">thickening</span><span lang="EN-US"> of stems </span><span lang="EN-US">which based on the changes in the anatomical structure: the thickness of bark, the diameter of bastfibres and the number of xylem elements in the row were increased. Formation of the more powerful stem significantly increased the lodging resistance of retardant treated linseed and created the technological advantages of mechanical harvesting. Chlormequat chloride treatment resulted<span> </span>the formation of powerful photosynthetic apparatus. The application of retardant increased the number of leaves per plant, as well as the period of their active functioning was prolonged. We also noted that </span><span lang="EN-US">the application of plant growth regulators led</span><span lang="EN-US"> to</span><span lang="EN-US"> increase the</span><span lang="EN-US"> cells size and volume of palisade chlorenchyma, the chloroplast number and size in palisade and spongy parenchyma. Such changes in the mesostructure measurement of leaves lead to increase the net photosynthetic productivity and more intense accretation of linseed dry weight matter.Consequantly, retardant treatment improved the gross photosynthetic productivity of linseed, that was the important prerequisite for enhancement of crop production. Application of chlormequat chloride resulted on the formation of higher amount of carbohydrates in the leaves, which formed a significant reserve of assimilates for the strong stem growth, formation of fruits and seeds ripening. At the period of fruit formation, the processes of morphogenesis and vegetative growth slowed down so carpogenesis was a powerful acceptor of organic compounds. The flow of assimilates was directed to the development of generative organs – fruits, the number of which increased by the drug as a result of intensive branching of the stem. </span><span lang="EN-US">The number of seeds per fruit, the weight of a single seed and seed weight of linseed increased under the influence of growth regulator. </span><span lang="EN-GB">Application of retardant stimulated a more intense synthesis of reserve compounds in the seeds that increased the yield of linseed oil. </span><span lang="EN-US">T</span><span lang="EN-GB">he analysis of iodine number, qualitative composition and quantitative content of fatty acids indicates that the growth regulator improved the qualitative parameters and degree of unsaturation of linseed oil. </span><span lang="EN-US">It was established that </span><span lang="EN-US">chlormequat chloride did n<span>ot accumulated in excessive amounts in linseed plants. The amount of residual drugs substance in the seeds was significantly lower than the permissible concentrations</span>, <span>which made it possible to use seeds and linseed oil in the food and pharmaceutical industries. We concluded that the application of </span>chlormequat chloride <span>on the linseed during the budding period with standard cultivation technology leads to morphological restructuring of plants, improve the development of leaf apparatus and formation of fruits, which contributed to the improvement of crop production.</span></span></p>

Two tank-mix adjuvants effect on yield and quality attributes of wheat treated with growth retardants

ABSTRACT: The objective of this study was to evaluate the quality of seeds and yield of winter wheat under different retardants application. The two years field trials on winter wheat were carried out in the Institute of Plant Protection - National Research Institute in Poznan (Poland). Treatments consisted of trinexapac-ethyl, chlormequat and prohexadione calcium applied in mixtures with paraffin oil adjuvant or organosilicone surfactant in BBCH 31 growth stage of winter wheat. No lodging occurred in any experimental year. The retardants had varying effect on the quality parameters of wheat grain. The highest fluctuations in the content of protein, gluten and the Zeleny value were observed after the application of chlormequat chloride. Starch content in wheat grain, regardless of the retardant application method, was negatively correlated with others grain quality parameters evaluated in the experiment. Depending on the year of study and weather conditions, increased or decreased wheat quality.

The effect of application time of cycocel hormone and plant density on yield and yield components of wheat (Chamran cultivar) in Ahvaz weather conditions

In order to study the effect of plant density and cycocel (CCC) on yield and yield components of wheat (Chamran cultivar), a split plot experiment in randomized complete block design with four replications was carried out in Shahid Salemi field in Ahvaz during 2011-2012 croping season. The treatments included three levels of plant density (400, 600, 800 plants/m2) and application time of cycocel hormone including lack of cycocel foliar spray (C0), cycocel foliar spray at 4-leaf stage (C1), and cycocel foliar spray at the beginning of stem elongation (C3). The results showed that during the application of chlormequat chloride, number of spikes per square meter, 1000-grain weight and grain yield significantly increased as compared to control treatment, while the number of grains per spike decreased. With increasing density from 400 to 800 plants/m 2 , the grain yield, number of spikes per square meter, number of grains per spike and 1000-grain weight decreased, While there was no significant difference between 400 and 600 plants/m2. The highest grain yield was recorded at 400 plants/m 2 and application of chlormequat chloride at 4-leaf stage and the lowest grain yield was obtained at 800

Management of sunflower stand height using growth regulators

Influence of growth regulators chlormequat chloride, ethephon, trinexapac-ethyl, and a combination of chlormequat chloride and ethephon on decreasing sunflower height was examined in the years 2006–2009. Height was reduced by as much as 63 cm by double application of chlormequat chloride (915 g/ha) + ethephon (465 g/ha) at early and later growth stage (BBCH 32 and 50). Trinexapac-ethyl (375 g/ha) did not affect the height. One-time application of chlormequat chloride (1440–2160 g/ha), chlormequat chloride (458 g/ha) + ethephon (233 g/ha) (BBCH 30 or 50), or ethephon (480 g/ha) (BBCH 30) was sufficient for a ca 30 cm reduction during flowering, but this effect did not last until harvest. With double application (BBCH 30 and 50), reduction lasted until harvest. For ethephon (480 g/ha), application at BBCH 50 reduced height by as much as 35 cm and lasted until harvest. Combining a lower rate of ethephon with ammonium sulfate was effectively equivalent to using a full rate. Flower head diameter at maturity showed no significant negative influence compared to the control. In 2008 and 2009, a delay in flowering onset was observed after applying growth regulators.

Influence of chlormequat chloride (CCC) and phosphorus on growth and yield of groundnut (Arachis hypogaea) during the summer season in North West India

Results of an experiment conducted during the summer seasons of 1990 and 1991 in North West India revealed that a Spanish semi-spreading type groundnut cultivar ICGS 1 produced 93% higher pod yield than a Valencia bunch type MH 2. Application of chlormequat chloride (CCC) to both cultivars at 0·5 ml/l water enhanced yield by 17%. An input of 13 kg P/ha increased the pod output significantly over control.

Comparison of Silverleaf Whitefly-Induced and Chlormequat Chloride-Induced Leaf Silvering inCucurbita pepo

Whitefly-mediated squash silverleaf is induced by the feeding of nymphs of the silverleaf whitefly, Bemisia argentifolii, but the mechanism involved in symptom expression is unknown. Several plant biochemical regulators were tested to determine whether they could mitigate expression of squash silverleaf in Cucurbita pepo. Application of chlormequat chloride, a gibberellic acid biosynthesis inhibitor, induced leaf silvering symptoms similar to those induced by the silverleaf whitefly in squash plants, cvs. Senator and Dixie, but not in cv. Small Sugar Pumpkin. Chlormequat chloride-induced silvering never extended over more than 80% of the upper leaf surface, compared with 100% for whitefly-induced silverleaf. Paclobutrazol, but not Alar, also produced leaf silvering symptoms. Chlormequat chloride treatment also resulted in internodal stem shortening, increased chlorophyll levels, and increased root and stem weight in Small Sugar Pumpkin and Senator but not in Dixie. Chlormequat chloride did not produce detectable double-stranded RNAs (dsRNAs) or changes in intercellular fluid proteins in any of the C. pepo cultivars tested. Silvered leaves from whitefly-infested plants, in contrast, had 15 to 40% lower chlorophyll levels, two induced intercellular leaf proteins, and some reductions in foliar and root biomass. No dsRNAs were detected in whitefly-silvered tissues or plants. Gibberellic acid applied after chlormequat chloride or paclobutrazol treatment resulted in less internodal shortening and decreased both chemical- and whitefly-induced leaf silvering. Chlormequat chloride-treated plants attracted greater whitefly oviposition and had more nymphs than untreated controls in greenhouse tests. These data suggest that leaf silvering induced by gibberellic acid biosynthesis inhibitors and by the silverleaf whitefly results from hormonally mediated alterations in the plant's physiology. Because the silverleaf whitefly also induces discoloration disorders in plants other than squash, hormonal inhibition may be a general component of whitefly phytotoxicity.

Effect of hand pinching and plant growth regulators on seed production of field grown hybrid dahlia

Abstract The effects of hand pinching above node four on the main stem and the application of the plant growth regulators paclobutrazol and chlormequat chloride on seed production of field grown hybrid dahlia ‘Unwins Mixed’ were investigated over two seasons at the same site. Pinching reduced the spread of flowering and resulted in seed heads at approximately the same height above ground level because of the promotion of lateral branch length, but did not increase seed yield. Seed yield perplant was significantly increased following the application of chlormequat chloride at 1.5 kg a.i./ha at stem elongation in the first season, and by paclobutrazol applied at 1.0 kg a.i./ ha at the appearance of the first visible flower bud in both seasons, the former through the production of more seed heads/plant, and the latter through a significant increase in seeds/seed head in one season and seed heads/plant in the following season. Other seed yield components did not differ among treatments. Plant growth retarding effects were transitory and floral development and flower numbers were not altered by the plant growth regulators. Although results were inconsistent, chemical manipulation of this hybrid dahlia shows promise for seed production and warrants further investigation.

Effect of imazaquin on absorption, translocation, and pattern of distribution of chlormequat chloride in winter wheat

The role of imazaquin in the absorption, translocation, and distribution of chlormequat chloride in CYCOCEL* CL has been studied in winter wheat. Three treatments were applied to the 5th leaf of the main stem at growth stage 5 (Feekes Large scale): (1)14C-chlormequat chloride, (2) CYCOCEL* CL containing14C-chlormequat chloride, and (3) CYCOCEL* CL containing14C-imazaquin. Tracing of the radioactivity was followed in the treated leaf, main stem, tillers, and roots. Results showed that more than 85% of the radioactivity absorbed remained in the treated leaf. Ten days after the application of chlormequat chloride alone, 94.4% of the14C-chlormequat was found in the treated leaf, 2.9% in the main stem, 1.2% in the tillers, and 1.4% in the root system versus 88.2, 8.2, 2.1, and 1.4%, respectively, for the chlormequat chloride plus imazaquin treatment. It was concluded that imazaquin increases the mobility and the pattern of distribution of chlormequat chloride in the plant.

The relation between cell size, ploidy level and nitrate concentration in lettuce

In two experiments the relation between cell size, ploidy level and nitrate concentration of genotypes of lettuce (Lactuca saliva L.) was investigated. Artificial increase of cell size by application of gibberellic acid to young plants decreased the percentage dry weight and the concentration of organic acids in the plant sap and increased the nitrate concentration of the shoot. Application of chlormequat chloride caused the opposite effects. Tetraploid genotypes of lettuce had larger cells, a lower nitrate concentration and a higher concentration of organic solutes than diploid genotypes. Genotypical differences in nitrate concentration could not be explained by differences in cell size, but were consistently related to differences in concentration of organic acids in plant sap. The percentage dry weight of genotypes was positively correlated with the concentration of organic acids in plant sap. However, differences in nitrate concentration were also found among genotypes with comparable dry matter content. These differences could be caused by differences in partitioning of photosynthates over structural components and organic acids in the vacuoles. Mono‐saccharides seem to be less important than organic acids for explaining genotypical differences in nitrate level, because the concentration of monosaccharides was much lower than that of organic acids and because a negative relation between the concentration of monosaccharides and of nitrate was not found in every case. Genotypical differences in nitrate accumulation were not related to differences in osmolarity.

Effects of growth retardants on inflorescence development in tomato

The growth retardant (2-chloroethyl)trimethylammonium chloride (chlormequat chloride), applied as a soil drench to young tomato plants (Lycopersicon esculentum Mill.), was effective in reducing the abortion of flower buds that occurred under winter conditions in the glasshouse. Application of chlormequat chloride also reduced flower abortion that occurred in response to a shading treatment or to high night temperatures. A second growth retardant, tributyl-2,4-dichlorobenzylphosphonium chloride (chlorphonium chloride), showed activity similar to that of chlormequat chloride. It is suggested that abortion of the flower buds occurred when vegetative parts of the shoot system were in competition with the inflorescence for metabolites or growth substances, and that the growth retardants acted to reduce or remove this competition.