Topic
Gibberellic acid
About: Gibberellic acid is a research topic. Over the lifetime, 6597 publications have been published within this topic receiving 109294 citations. The topic is also known as: GIBBERELLIN A3.
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TL;DR: The amount of callose in sieve tube cells correlated with levels of β-1, 3-glucanase, suggesting that this enzyme played a role in the degradation ofβ-1- 3- glucans.
Abstract: The endo-beta-1, 3-glucanase (beta-1, 3-glucan 3-glucanhydrolase, EC 3216) extracted from Phaseolus vulgaris L cv Red Kidney had a pH optimum of 5 and a temperature optimum of 50 C Excision of plant tissue resulted in an increase in beta-1, 3-glucanase activity after a 6-hour lag period The increase could be prevented by indole-3-acetic acid, gibberellic acid, and cytokinins Ethylene (half-maximal concentration = 01 microliter/liter) promoted the synthesis of beta-1, 3-glucanase, and 10% CO(2) overcame some of the ethylene effect Cycloheximide prevented the induction of beta-1, 3-glucanase, but actinomycin D and chromomycin A(3) had only a partial effect The amount of callose in sieve tube cells correlated with levels of beta-1, 3-glucanase, suggesting that this enzyme played a role in the degradation of beta-1, 3-glucans
199 citations
TL;DR: Two recent reports have indicated that RGL1 and RGL2, both homologous to the GA-response height-regulating factors GAI/RGA/RHT/d8/SLR1/SLN1, are repressors of seed germination in Arabidopsis, providing new clues as to how GA controls seeds germination.
196 citations
TL;DR: It is inferred that there must be at least two populations of alpha-amylase mRNA molecules derived from separate structural genes differently influenced by gibberellic acid in aleurone cells.
196 citations
TL;DR: Ethylene may cause internodal elongation in rice by increasing the activity of endogenous GAs in internodes from which the leaf sheath had been peeled off, and growth in response to submergence, ethylene and GA(3) was severely inhibited by light.
Abstract: We have shown previously that ethylene, which accumulates in the air spaces of submerged stem sections of rice (Oryza sativa L. cv "Habiganj Aman II"), is involved in regulating the growth response caused by submergence. The role of gibberellins in the submergence response was studied using tetcyclacis (TCY), a new plant growth retardant, which inhibits gibberellin biosynthesis. Stem sections excised from plants that had been watered with a solution of 1 micromolar TCY for 7 to 10 days did not elongate when submerged in the same solution or when exposed to 1 microliter per liter ethylene in air. Gibberellic acid (GA(3)) at 0.3 micromolar overcame the effect of TCY and restored the rapid internodal elongation in submerged and ethylene-treated sections to the levels observed in control sections that had not been treated with TCY. The effect of 0.01 to 0.2 micromolar GA(3) on internodal elongation was enhanced two- to eight-fold when 1 microliter per liter ethylene was added to the air passing through the chamber in which the sections were incubated. GA(3) and ethylene caused a similar increase in cell division and cell elongation in rice internodes. Thus, ethylene may cause internodal elongation in rice by increasing the activity of endogenous GAs. In internodes from which the leaf sheath had been peeled off, growth in response to submergence, ethylene and GA(3) was severely inhibited by light.
192 citations
TL;DR: To elucidate if the capacity to produce phytoene is limiting also in the seed of Arabidopsis, a gene coding for an endogenous phy toene synthase was cloned and coupled to a seed-specific promoter, and the effects of the overexpression were examined.
Abstract: Phytoene synthase catalyzes the dimerization of two molecules of geranylgeranyl pyrophosphate to phytoene and has been shown to be rate limiting for the synthesis of carotenoids. To elucidate if the capacity to produce phytoene is limiting also in the seed of Arabidopsis (Wassilewskija), a gene coding for an endogenous phytoene synthase was cloned and coupled to a seed-specific promoter, and the effects of the overexpression were examined. The resulting transgenic plants produced darker seeds, and extracts from the seed of five overexpressing plants had a 43-fold average increase of β-carotene and a total average amount of β-carotene of approximately 260 μg g – 1 fresh weight. Lutein, violaxanthin, and chlorophyll were significantly increased, whereas the levels of zeaxanthin only increased by a factor 1.1. In addition, substantial levels of lycopene and α-carotene were produced in the seeds, whereas only trace amounts were found in the control plants. Seeds from the transgenic plants exhibited delayed germination, and the degree of delay was positively correlated with the increased levels of carotenoids. The abscisic acid levels followed the increase of the carotenoids, and plants having the highest carotenoid levels also had the highest abscisic acid content. Addition of gibberellic acid to the growth medium only partly restored germination of the transgenic seeds.
191 citations