scholarly journals Differences in Inflorescence Numbers and Endogenous Gibberellic Acid Levels in ‘Afterglow’ Bougainvillea

2020 ◽  
Vol 30 (6) ◽  
pp. 650-653
Author(s):  
Mun Wye Chng ◽  
Kimberly A. Moore

Bougainvillea (Bougainvillea sp.) plant inflorescence number will vary in response to multiple cues such as changes in temperature, water, light intensity, pruning, and photoperiod. Previous research reports that the application of plant growth regulators (PGRs) to bougainvillea grown under varying photoperiods improved inflorescence number, probably as a result of changes in gibberellic acid (GA) levels. There are many bioactive plant GAs, but we chose to investigate differences in gibberellic acid 3 (GA3) levels and inflorescence number in response to the application of ethephon (2-cholorethylphosponic acid) or abscisic acid (ABA) to ‘Afterglow’ bougainvillea (Bougainvillea ×buttiana) grown under 14-hour photoperiod [long-day (LD)] conditions. Plants were 5 inches tall with seven visible lateral nodes and were grown in a greenhouse in 4-inch pots filled with 5-mm coarse aquarium zeolite. Ethephon was applied as a foliar spray at 0.05, 0.07, 0.10, 0.15, or 0.20 mg/plant. ABA was applied as a soil drench at 1, 1.5, 3, 6, 8, or 10 mg/plant. Endogenous levels of GA3 were measured 1 and 48 days after treatment to calculate the change in GA3 (∆GA3). A short day (SD) control of 8 hours was included to measure differences in inflorescence number and ∆GA3 between photoperiods. ‘Afterglow’ plants grown under SD conditions had the greatest decrease in ∆GA3 (–1.09 µg·g–1) over 48 days and the most inflorescences (10.6) compared with LD control plants with a decrease in ∆GA3 of –0.09 µg·g–1 and fewer inflorescences (1.0). Plants grown under LD conditions and treated with 0.05 mg/plant ethephon had inflorescence numbers (9.6) and levels of ∆GA3 (–0.74 µg·g–1) similar to the SD control. As ethephon rate increased to more than 0.05 mg/plant, inflorescence number on LD plants decreased and ∆GA3 increased. Exogenous ABA rates of 1 mg/plant produced inflorescence numbers (1.4) and ∆GA3 (–0.10 µg·g–1) similar to the LD control. As the rate increased, ∆GA3 increased and inflorescence number decreased. Plants treated with ABA rates of 3 mg/plant and more were defoliated and had no inflorescences.

2016 ◽  
Vol 69 (1) ◽  
Author(s):  
Marian Saniewski ◽  
Justyna Góraj-Koniarska ◽  
Elżbieta Węgrzynowicz-Lesiak ◽  
Eleonora Gabryszewska

It is known that chilling of <em>Muscari</em> bulbs is necessary for the growth of the inflorescence stalk and flowering, but not for the growth of leaves. Gibberellic acid (GA) accelerated stem growth and flowering in chilled <em>Muscari</em> bulbs. In the present experiment it was shown that in unchilled derooted <em>Muscari</em> bulbs the growth of leaves, but not the growth of the inflorescence stalk, was observed when bulbs were stored in water, GA at a concentration of 50 and 100 mg/L, benzyladenine (BA) at a concentration of 25 and 50 mg/L, or a mixture of GA+BA (50+25 mg/L), but abscisic acid (ABA) at a concentration of 10 mg/L greatly inhibited the growth of leaves. In chilled derooted <em>Muscari</em> bulbs the growth of leaves and inflorescence stalk was observed when bulbs were stored in water or GA, but BA and GA+BA treatments totally inhibited the growth of the inflorescence stalk without an effect on the growth of leaves. These results clearly showed that the growth of leaves and inflorescence stalk in <em>Muscari</em> bulbs are controlled by plant growth regulators in different ways. ABA totally inhibited the growth of leaves and inflorescence stalk in chilled derooted <em>Muscari</em> bulbs. It was shown that after the excision of the inflorescence bud in cultivated chilled <em>Muscari</em> bulbs, the inflorescence stalk died, but application of indole-3-acetic acid (IAA) 0.5% in the place of the removed inflorescence bud induced the growth of the inflorescence stalk. IAA applied under the inflorescence bud inhibited the development of flowers (flower-bud blasting) and induced the growth of the inflorescence stalk below the treatment site. These results are discussed with reference to hormonal regulation of stem (stalk) growth in tulip, narcissus, hyacinth, and <em>Hippeastrum</em>.


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.


HortScience ◽  
2003 ◽  
Vol 38 (4) ◽  
pp. 599-600
Author(s):  
Vincent M. Russo

Exogenously applied plant growth regulators may affect development of onion, but little is know about how concentration or timing of application can affect bulb grade and quality. Two concentrations of the growth regulators abscisic acid, gibberellic acid, indole-acetic acid, jasmonic acid, kinetin, and maleic acid hydrazide, and water controls, were applied at the 7- and 20-leaf stages to the middle of the leaf whorl in greenhouse grown onion plants. Leaf and bulb weights were lighter, and bulb diameters were smaller, from plants treated with growth regulators applied at the 7-leaf stage than those from plants treated at the 20-leaf stage. Bulbs produced on plants treated with water were the same size, or larger, than those produced on plants treated with individual growth regulators.


2016 ◽  
Vol 38 (3) ◽  
Author(s):  
JULIANA DOMINGUES LIMA ◽  
JÉSSICA SANTA ROSA ◽  
DANILO EDUARDO ROZANE ◽  
EDUARDO NARDINI GOMES ◽  
SILVIA HELENA MODENESE GORLA DA SILVA

ABSTRACT Plant growth regulators can influence fruit yield and quality. This study aimed to evaluate the effect of cytokinin and gibberelin on the agronomic and physicochemical characteristics of banana fruits cv. ‘Prata’ (Musa spp. AAB), according to the formation period and position in the bunch. The experiment was conducted in a completely randomized 2 x 5 factorial design, two periods of bunch development (summer and winter), five treatments and ten replicates. To study the effect of position in the bunch, split plot was adopted, considering in the plot, 2 x 5 factorial and in subplots, hand 1, hand 4 and last hand. Treatments consisted of 2 pulverizations with water, 150 mg L-1 cytokinin, 200 mg L-1 of gibberellic acid, 100 mg L-1 of cytokinin plus 200 mg L-1 of gibberellic acid and 200 mg L-1 of cytokinin plus 200 mg L-1 of gibberellic acid, applied from the fourth to the last hand of the bunch. Cytokinin and gibberellin, alone or associated, regardless of formation period and position, did not affect the size and physicochemical characteristics of fruits, only delayed the bunch harvest.


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.


2020 ◽  
Vol 15 (3) ◽  
Author(s):  
El Hadi Hadia ◽  
Amor Slama ◽  
Leila Romdhane ◽  
Hatem Cheikh M’hamed ◽  
Ahmed Houssein Abodoma ◽  
...  

To study the effects of salt stress and plant growth regulators (kinetin, gibberellic acid, potassium) on growth, yield, glycine betaine content, phosphoenolpyruvate carboxylase (PEPC) and ribulose biphosphate carboxylase (RBC) gene expression of two Libyan bread wheat varieties, a factorial design of greenhouse experiment with three replications was conducted. Results revealed that salt stress significantly reduced plant growth and productivity of both varieties. Moreover, the addition of kinetin + potassium and gibberellic acid + potassium had improved the performance of the morpho-metric parameters of both genotypes under salt stress; but the performance was more effective for kinetin treatment than for gibberellic acid. At the biochemical level, the results showed that salt stress increased glycine betaine contents in both varieties with different proportions. This increase is more elevated in the presence of kinetin + potassium than the treatment with gibberellic acid+ potassium, which showed an almost similar result as in only salt stress. At the molecular level, the effects of salt stress and plant growth regulators on the PEPC and RBC gene expression showed that the increase was significantly higher for kinetin, gibberellic acid, and salt stress when compared to the control.


2021 ◽  
Vol 10 (2) ◽  
pp. e27110212471
Author(s):  
Aline Bueno Ramalho ◽  
Lúcia Filgueiras Braga

Plant growth regulators in the germination of Diospyros hispida A. DC. (Ebenaceae) Seed. Diospyros hispida species is a native fruit that has long germination period, hindering seedling production. The aim of this work was to evaluate the germination of Diospyros hispida seeds under the effect of gibberellic acid and biostimulant applications. Four replicates of 25 seeds per treatment were used. Treatments were: T1 - distilled water, T2, T3 and T4 - GA3 solutions at 100, 150 and 200 mg L-1, respectively, T5 - Immersion for 24 hours in distilled water with aeration, T6, T7 and T8 - Immersion for 24 hours in aerated GA3 solutions at 100, 150 and 200 mg L-1, respectively, T9, T10 and T11 - biostimulant application (containing auxin, gibberellin and cytokinin) at 3, 5 and 7 ml kg-1 of seeds. Germination rate, mean germination time, germination speed index, synchronization index, relative germination frequency, normal seedlings, root length, shoot length and seedling dry mass were evaluated. The effect of gibberellic acid and biostimulant containing auxin, gibberellin and cytokinin negatively influenced Diospyros hispida germination under the conditions of this study.


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