scholarly journals Paclobutrazol as a plant growth regulator

Author(s):  
Bizuayehu Desta ◽  
Getachew Amare

AbstractPlant growth regulators are chemical substances which govern all the factors of development and growth within plants. The application of plant growth regulators to crops modifies hormonal balance and growth leading to increased yield, enhanced crop tolerance against abiotic stress and improved physiological trait of crops. Paclobutrazol (PBZ) [(2RS, 3RS)-1-(4-chlorophenyl)- 4, 4-dimethyl-2-(1H-1, 2, 4-trizol-1-yl)-pentan-3-ol], is one of the members of triazole family having growth regulating property. The growth regulating properties of PBZ are mediated by changes in the levels of important plant hormones including the gibberellins (GAs), abscisic acid (ABA) and cytokinins (CK). PBZ affects the isoprenoid pathway, and alters the levels of plant hormones by inhibiting gibberellin synthesis and increasing cytokinins level and consequent reduction in stem elongation. When gibberellins synthesis is inhibited, more precursors in the terpenoid pathway accumulate and that resulted in the production of abscisic acid. PBZ is more effective when applied to the growing media and application on the growing medium would give longer absorption time and more absorption of active ingredient than foliar spray. The application of PBZ to crops is important in reducing plant height to prevent lodging and in increasing number and weight of fruits per tree, in improving the fruit quality in terms of increases in carbohydrates, TSS, TSS/TA and decreases acidity. It further reduces evapo-transpiration and decreases plant moisture stress by enhancing the relative water content of leaf area and develops resistance in the plants against biotic and abiotic stresses. In addition, it acts as highly active systemic fungicide and used against several economically important fungal diseases. In this review, the current knowledge and possible applications of PBZ, which can be used to improve the growth, yield and quality of crops, have been reviewed and discussed. The role of PBZ to mitigate the harmful effects of environmental stresses in crops is also examined. Moreover, various biochemical and physiological processes leading to improved crop production under the effect of PBZ are discoursed in detail.

2012 ◽  
Vol 22 (3) ◽  
pp. 338-344 ◽  
Author(s):  
Christopher J. Currey ◽  
John E. Erwin

Our objectives were to assess the efficacy of various plant growth regulators (PGRs) on stem elongation and branching of 11 kalanchoe (Kalanchoe) species with ornamental characteristics: beauvard’s widow’s-thrill (K. beauvardii), K. glaucescens, lavender scallops or red-leaved kalanchoe (K. fedtschenkoi), K. longiflora, chandelier plant (K. manginii), marnier’s kalanchoe (K. marnieriana), K. millotii, flower dust plant (K. pumila), K. rosei, common kalanchoe or nentabos (K. rotundifolia), and K. streptantha. Foliar spray applications of deionized water, ancymidol (15−60 ppm), benzyladenine (75−300 ppm), chlormequat chloride (750−3000 ppm), daminozide (1250−5000 ppm), ethephon (250−1000 ppm), paclobutrazol (10−40 ppm), or uniconazole (5−20 ppm) were applied 2 weeks after plants were pinched. Stem length at the time of application and 4 weeks after applications and branch number were recorded. While effective chemicals and concentrations varied widely among species, paclobutrazol and uniconazole were identified as providing broad efficacy with respect to inhibition of stem elongation across all 11 species in this study. Additionally, benzyladenine and ethephon increased the number of branches for several species.


1977 ◽  
Vol 4 (3) ◽  
pp. 359 ◽  
Author(s):  
RP Zigas ◽  
BG Coombe

Treatment of peach embryos from partially stratified seeds with abscisic acid (ABA) inhibited germination and promoted the production of leaf lesions, responses which are typical of testa presence. A period of water stress during germination also promoted lesion production. Neither testas nor ABA stimulated lesions on seedlings from 25°C-stratified seed, but mixtures of ABA and GA*3 were synergistic in promoting lesions; at the same time ABA and GA3 had opposite effects on germination and stem elongation, and mixtures had intermediate effects. Evidence was obtained for effects attributable to a balance between GA and ABA. Other inhibitors and promotors had no effect on lesions. The results from excision and substitution experiments permit an explanation of the effects of stratification in terms of three events: (a) a decrease in inhibitor activity in the testa; (b) an increase in gibberellin activity in the epicotyl; and (c) diffusion of inhibitor to the epicotyl via the radicle when the seed is returned to warm conditions.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hammad Ishtiaq ◽  
Savita Bhardwaj ◽  
Aaliya Ashraf ◽  
Dhriti Kapoor

Plant growth regulators are significant chemical compounds which are synthesized inside the plant cells and play vital role in plant growth and development. Such compounds are usually active at very low concentrations. These plant growth regulators act as a signalling molecule, which influences the growth of plants. Throughout the previous year’s remarkable investigation have been done for understanding the synthesis of auxin and its effect on various physiological progressions. Auxin is a plant hormone that is involved in various physiological activities, including basic cellular processes such as cell enlargement, regulation of the cell cycle and distinction progress. Plants and several other microorganisms together produce auxin in order to carry out their cell cycle. The chemically synthesized auxins like NAA (naphthalene acetic acid) and IBA (Indole- butyric acid), also take part in various cellular processes. Against various types of biotic and abiotic stress conditions, these plant hormones significantly contribute in promoting acclimatization and adaptation in combination with other phytohormones. The present review highlights some of the important features of auxin role in regulation of plant growth either alone or in crosstalk with other plant hormones.


2008 ◽  
Vol 13 (1-2) ◽  
pp. 186 ◽  
Author(s):  
A. RAJALA

Plant growth regulators (PGRs) are exogenously applied chemicals that alter plant metabolism, cell division, cell enlargement, growth and development by regulating plant hormones or other biological signals. For example, some PGRs regulate stem elongation by inhibiting biosynthesis of gibberellins or through releasing ethylene. PGR effects are widely studied and reported on barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.), whereas there are only a few reports addressing oat (Avena sativa L.). This is likely to be a result of smaller acreage and lower intensity of oat management and production and hence a reduced need for stem shortening by PGRs. However, this is not the case for all cereal producing regions and there exists a need to understand the potential application of PGRs to oat production. This paper represents a review of the potential of PGRs to regulate stem elongation and other biological traits governing plant stand structure and yield components, with special emphasis on oat and its responses to PGRs. Yield improvement requires more heads per unit land area, more grains per head or heavier grains. Of these yield-determining parameters, the number of head bearing tillers and grain numbers per head, compared with grain weight, are more likely to be improved by PGR application. In the absence of lodging, PGR may reduce grain yield due to potential reduction in mean grain weight and/or grain number. Cultivation systems aiming at extensive yields with intensive use of inputs likely benefit from PGR applications more often compared with low or moderate input cultivation, for which cost effectiveness of PGRs is not frequently reached.;


2019 ◽  
Vol 60 (11) ◽  
pp. 69-74
Author(s):  
Valery N. Zelenkov ◽  
◽  
Vladimir N. Petrichenko ◽  
Anatoly A. Lapin ◽  
Viktor P. Baryshok ◽  
...  

Currently, the expansion of research to find new efficient and environmentally friendly plant growth regulators is an urgent task of agricultural biotechnology. One of the main requirements of the modern development of crop production using technologies for the use of new plant growth regulators is, along with the environmental friendliness of new drugs, both at the application stage for foliar feeding of plants and improving the quality of the final product. One of the new drugs that meet these requirements is a complex preparation of 1-ethoxysilatrane with crezacin. The work shows the high efficiency of the use of the new apple growth regulator in the processing of apple leaves. As a result of the studies, a synergism of the joint action of 1-ethoxysilatrane and crezacin as part of a complex preparation was revealed during foliar treatment of apple leaves of 3-4 phases and the beginning of flowering by spraying the drug in doses of 15 g/ha. The total increase in apple harvest during foliar treatment of tree leaves was 8.1% or 7.0 t/ha compared with the control. An increase in the quality indicators of gardening products was revealed when using the drug 1-ethoxysilatran with krezacin in terms of the content of dry substances, total sugar, vitamin C and pectin in the fruits. The content in the fruits of nitrates during foliar treatment with a new preparation of tree leaves is reduced by 17.9% compared with the control. The content in the fruits of apples of nitrates during foliar treatment with a new preparation of tree leaves decreases by 17.9%, the lead content by 44% compared with the control.


2017 ◽  
Vol 52 (11) ◽  
pp. 1118-1122 ◽  
Author(s):  
Alberto Fontanella Brighenti ◽  
Douglas André Würz ◽  
Mateus da Silveira Pasa ◽  
Leo Rufato

Abstract: The objective of this work was to investigate the effect of plant growth regulators for enhancing fruit color of 'Gala Standard' apples (Malus domestica). The experiment was carried out in the 2015 and 2016 crop seasons. The treatments consisted of water, as a control; 300 mg L-1 ethephon, as a positive control; 400 mg L-1 prohydrojasmonate; and 400 mg L-1 abscisic acid. Flesh firmness, soluble solids content, fruit weight, and red color were assessed after harvest. Plant growth regulators enhanced red color of fruit and chlorophyll degradation. Prohydrojasmonate and abscisic acid did not reduce flesh firmness, in the 2016 season.


Author(s):  
Zahida Rashid ◽  
Tanveer Ahmad Ahngar ◽  
B. Sabiya ◽  
N. Sabina ◽  
N. S. Khuroo ◽  
...  

A field experiment was conducted at Dry land Agricultural Research Station, Rangreth, Srinagar, SKUAST-K in Kharif 2020 to study the effect of Plant Growth Regulators and micronutrients on growth, yield and quality of sorghum. The objective of the study was to assess the effect of Plant Growth Regulators and micronutrients on herbage yield and quality. The treatments included; T1: Tricontanol 10 ppm at 30 DAS (foliar spray), T2: Salicylic acid 100 ppm at 30 DAS (foliar spray), T3: 5 kg Zn/ha soil application, T4: 2 kg B/ha soil application, T5: 5 kg Zn + 2 kg B/ha soil application, T6: 5 kg Zn/ha (soil application ) + Triacontanol 10 ppm at 30 DAS (foliar spray), T7: 5 kg Zn/ha (soil application) + salicylic acid 100 ppm at 30 DAS (foliar spray), T8: 2 kg B/ha (soil application) + Triacontanol 10 ppm at 30 DAS (foliar spray), T9: 2 kg B/ha (soil application )+ salicylic acid 100 ppm at 30 DAS (foliar spray), T10: 5 kg Zn + 2 kg B/ha (soil application) + Triacontanol 10 ppm at 30 DAS (foliar spray), T11: 5 kg Zn + 2 kg B/ha (soil application) + salicylic acid 100 ppm at 30 DAS (foliar spray) and T12: Water spray at the time of PGR application. Zn and B were applied at the time of sowing in the soil. The crop was raised with recommended package of practices. In treatments, where zinc was not a treatment, an amount of sulphur through gypsum equivalent to sulphate supplied with 5 kg ZnSO4 was applied to compensate. The crop was sown in 30.0 cm apart lines. The trial was laid out in Randomized Block Design with three replications. The results indicated that all the treatments improved the green fodder yield over control. Among different treatments, T10: 5 kg Zn + 2 kg B/ha soil application + Triacontanol 10 ppm at 30 DAS foliar spray and T11: 5 kg Zn + 2 kg B/ha soil application + salicylic acid 100 ppm at 30 DAS foliar spray produced maximum GFY (493.6 and 490.5q/ha) on locational mean basis. It was significantly superior to other treatments. These treatments improved the green fodder yields by 35.0 % and 34.2 %, respectively, over control (spray of water). In terms of dry matter, similar trend was noted and the improvement with T10 and T11 was to the tune of 36.8 % and 41.0 % over control. Tricontanol 10 ppm at 30 DAS (foliar spray) (T1) improved the green fodder yield and dry fodder yield by 13.6% and 14.3 % respectively over T12Water spray at the time of Plant Growth Regulator application. Similarly spray of T2: Salicylic acid 100 ppm at 30 DAS (foliar spray) improved the green fodder yield and dry fodder yield by 14.4% and 15.4% respectively over T12Water spray at the time of Plant Growth Regulator application. Similar trend was observed with respect to quality parameters (crude protein content and crude protein yield) of sorghum.


2006 ◽  
Vol 24 (3) ◽  
pp. 165-168
Author(s):  
Stanislav V. Magnitskiy ◽  
Claudio C. Pasian ◽  
Mark A. Bennett ◽  
James D. Metzger

Abstract Soaking French marigold seeds in growth regulator solutions produced larger reductions in seedling height than foliar sprays. Seeds soaked in 1 to 5 ppm uniconazole solutions for 0.15, 5, or 45 min resulted in plants that were up to 23% shorter than controls at 30 DAS, whereas foliar applications of 10 to 20 ppm uniconazole solutions resulted in plants 18% shorter than controls at 14 DAS. French marigold seedlings from seeds soaked in 60 pm ancymidol for 5 or 45 min were 5 or 6%, respectively, shorter than controls. Foliar spray applications of 25 or 100 ppm ancymidol to French marigold seedlings resulted in plants 8% shorter than controls. Chlormequat solutions applied either as a seed soak (1000–5000 ppm) or foliar spray (500–3000 ppm) did not reduce French marigold seedling height. Emergence of French marigold seedlings from seeds soaked in uniconazole, ancymidol, or chlormequat solutions was not different from that of control seeds. No effect on seedling height or emergence was found when soaking celosia seeds in uniconazole, ancymidol, or chlormequat solutions. Spraying celosia seedlings with uniconazole, ancymidol, or chlormequat solutions did not reduce seedling height.


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