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: An α-amylase gene from cassava tuberous roots is isolated and the predicted structural model of MEamy2 contains three domains, active sites and starch-binding domain that are common with other plant α-AMylases.
37 citations
TL;DR: Labeling experiments with radioactive glucose and fructose show that aleurone layers continuously synthesize sucrose and that the release, but not the synthesis of sucrose is enhanced by GA3.
Abstract: Aleurone layers of barley contain large amounts of a soluble oligosaccharide which was identified as sucrose (30–40 μg/mg fresh weight). Treatment of the layers with gibberellic acid (GA3) causes the release of sucrose from the cells. This release requires the participation of metabolic processes, including protein synthesis. When embryoless half-seeds are incubated sucrose accumulates in the aleurone layers, but when seeds are germinated the sucrose content of the aleurone layers declines. Labeling experiments with radioactive glucose and fructose show that aleurone layers continuously synthesize sucrose and that the release, but not the synthesis of sucrose is enhanced by GA3.
36 citations
TL;DR: Analysis of subtracted cDNA libraries prepared using the RNA isolated from the apical bud and the associated two leaves of actively growing AG and winter dormant plant showed the downregulation of genes involved in cell cycle/cell division and upregulation of stress-inducible genes including those encoding chaperons during WD.
Abstract: Gene networks modulated in winter dormancy (WD) in relation to temperature and hormone responses were analyzed in tea [Camellia sinensis (L.) O. Kuntze]. Analysis of subtracted cDNA libraries prepared using the RNA isolated from the apical bud and the associated two leaves (two and a bud, TAB) of actively growing (AG) and winter dormant plant showed the downregulation of genes involved in cell cycle/cell division and upregulation of stress-inducible genes including those encoding chaperons during WD. Low temperature (4°C) modulated gene expression in AG cut-shoots in similar fashion as observed in TAB during WD. In tissue harvested during WD, growth temperature (25°C) modulated gene expression in the similar way as observed during the period of active growth (PAG). Abscisic acid (ABA) and gibberellic acid (GA3) modulated expression of selected genes, depending upon if the tissue was harvested during PAG or WD. Tissue preparedness was critical for ABA- and GA3-mediated response, particularly for stress-responsive genes/chaperons. Data identified the common gene networks for winter dormancy, temperature, and plant hormone responses.
36 citations
TL;DR: The results from these experiments revealed that the morphogenetic pathway (shoot versus root differentiation) can be manipulated on flax explants by raising the 2,4-D level from 0.05 to 3.2 mg l−1 in the induction medium.
Abstract: The effects of plant growth regulators (PGR) on calli induction, morphogenesis and somatic embryogenesis of flax were studied. The organogenic and callus formation capacity were assessed for different types of source explants. Root and shoot explants were equally good material for calli production but the former produced calli without shoot regeneration capacity. Under the experimental conditions tested, 2,4-dichlorophenoxyacetic acid (2,4-D) + zeatin was the most efficient PGR combination on calli induction and biomass production. The calli were green but with no rhizogenic capacity. In contrast, and at similar concentrations, indole-3-butyric acid (IBA) + kinetin induced white or pale green friable calli with a good root regeneration capacity (60%). A factorial experiment with different combinations of 2,4-D + zeatin + gibberellic acid (GA3) levels revealed that the direction of explant differentiation was determined by specific PGR interactions and concentrations. The results from these experiments revealed that the morphogenetic pathway (shoot versus root differentiation) can be manipulated on flax explants by raising the 2,4-D level from 0.05 to 3.2 mg l−1 in the induction medium. The induction and development of somatic embryos from flax explants was possible in a range of 2,4-D + zeatin concentrations surrounding 0.4 mg l−1 2,4-D and 1.6 mg l−1 zeatin, the most efficient growth regulator combination.
36 citations
TL;DR: GA( 3) reversal of the red light-induced shift in the IAA dose-response curve involves both growth promotion and inhibition by GA(3) at different IAA concentrations, which supports the suggested regulatory role of phenolic compounds in growth.
Abstract: Red light inhibits the growth of etiolated pea internodes, causes a shift toward higher indoleacetic acid (IAA) concentrations in the IAA dose-response curve of excised sections, and promotes the synthesis in intact internodes of kaempferol-3-triglucoside. Gibberellic acid (GA(3)) prevents all 3 effects, the first effect substantially and the last 2 completely. This suggests GA(3) blockage of an early or basic event initiated by the active form of phytochrome. The red light-induced shift in the IAA dose-response curve of excised sections is consistent with a light-induced increase in the activity of an IAA destruction system, since the magnitude of the red light inhibition varied with IAA concentration. The red light and GA(3) effects on growth and on flavonoid synthesis are consistent with the view that phytochrome may control growth by regulating the synthesis of phenolic compounds which act as cofactors in an IAA-oxidase system. GA(3) reversal of the red light-induced shift in the IAA dose-response curve involves both growth promotion and inhibition by GA(3) at different IAA concentrations and this, together with the GA(3) reversal of light-induced flavonoid synthesis, supports the suggested regulatory role of phenolic compounds in growth.
36 citations