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.

Distribution of photoassimilates in the pea plant: chronology of events in non-fertilized ovaries and effects of gibberellic acid

Abstract: The short-lived isotope11C (t1/2=20.4 min) has been used to study assimilate distribution in intact pea plants (Pisum sativum L.). Radiolabel was measured at the leaf fed with11CO2 (feed-leaf), at the ovary of the flower subtended by this leaf, and in shoot apex and roots of individual plants. Considerable11C-radiolabel was detected in the young ovaries during the first days after anthesis. Thereafter, when the ovaries stopped growing the uptake of11C rapidly decreased. At this developmental stage only apex and roots were competing for the photoassimilates. Fertilization, however, restored the strong sink activity of the ovaries. The same effect could be achieved by applying gibberellic acid to non-fertilized ovaries. About 2 h after treatment the residual11C-radiolabel entering the ovary started to increase and, at about the same time, the ovary resumed growth. Feed-leaf photosynthesis, as well as export of11C-radiolabel out of the leaf, was not changed by the treatment. The11C experiments show the dynamic behaviour of the sinks during developmental stages from the day of anthesis until 5 d later and demonstrate that phytohormones may play an important role in regulating carbon distribution.

Influence of Etherel and Gibberellic Acid on Carbon Metabolism, Growth, and Essential Oil Accumulation in Spearmint (Mentha Spicata)

Abstract: Changes in growth parameters and 14CO2 and [U-14C]-sucrose incorporation into the primary metabolic pools and essential oil were investigated in leaves and stems of M. spicata treated with etherel and gibberellic acid (GA). Compared to the control, GA and etherel treatments induced significant phenotypic changes and a decrease in chlorophyll content, CO2 exchange rate, and stomatal conductance. Treatment with etherel led to increased total incorporation of 14CO2 into the leaves wheras total incorporation from 14C sucrose was decreased. When 14CO2 was fed, the incorporation into the ethanol soluble fraction, sugars, organic acids, and essential oil was significantly higher in etherel treated leaves than in the control. However, [U-14C]-sucrose feeding led to decreased label incorporation in the ethanol-soluble fraction, sugars, organic acids, and essential oils compared to the control. When 14CO2 was fed to GA treated leaves, label incorporation in ethanol-insoluble fraction, sugars, and oils was significantly higher than in the control. In contrast, when [U-14C]-sucrose was fed the incorporation in the ethanol soluble fraction, sugars, organic acids, and oil was significantly lower than in the control. Hence the hormone treatment induces a differential utilization of precursors for oil biosynthesis and accumulation and differences in partitioning of label between leaf and stem. Etherel and GA influence the partitioning of primary photosynthetic metabolites and thus modify plant growth and essential oil accumulation.

External Factors Inducing Germination of Fern Spores

Abstract: The dependence of spore germination on light in most species of ferns was established by nineteenth century biologists including Borodin, Schmidt, Kny, and Beck (see the excellent review of Sussman, 1965). However, there are conflicting reports on the ability of spores of certain species to germinate in the dark. For example, Borodin (1865), Schulz (1902), and Life (1907) were unable to demonstrate the germination of spores of Anemia phyllitidis in the dark, although Schelting (1875) claimed that it occurs. The light requirement for germination in various species has been found to be complex. Ability of spores to undergo dark germination may vary, for example, with age (Laage, 1907), with pretreatment at various temperatures (Heald, 1898; Schulz, 1902), or with exposure to various plant hormones. Reliable action spectra for light-induced promotion and inhibition of germination in species of Dryopteris and Osmunda (Biinning and Mohr, 1955; M\ohr, 1956; Mohr et al., 1964) show maxima at the absorption maxima of phytochrome. Gibberellic acid stimulation of dark germination, reported by Schraudolf (1962), was the first true case of a specific replacement of a light requirement in spore germination. Kato (1955) reported a gibberellin stimulation of germination in Dryopteris erythrosora and Cyathea sp., but this consisted merely of gibberellin promotion of rhizoid and protonemal growth in light. M'ore recently Naf (1966) has confirmed Schraudolf's observations and reported that dark germination is stimulated in Lygodium japonicum by gibberellic acid and in Anemia phyllitidis by an antheridogen-B preparation as well as by gibberellin. Naf also claimed a weak stimulation of germination of L. japonicum by antheridogen-B and by the medium upon which L. japonicum had been growing. However, these latter results seem to be based on counts of only

High frequency plant regeneration from immature cotyledons of mungbean

Abstract: An efficient and simple method for high frequency plant regeneration from immature cotyledons of mungbean is described. Immature cotyledons isolated from embryos, one week prior to harvest were cultured on MS medium with combinations of growth regulators such as benzyladenine (1 or 2 mg l−1), thidiazuron (0.1 or 0.5 mg l−1), gibberellic acid (0.1 mg l−1) and indole-3-acetic acid (0.1 or 0.5 mg l−1). A large number of greenish shoot primordia were initiated from the entire surface of the cotyledons in some of the growth regulators. Medium supplemented with benzyladenine (2 mg l−1) in combination with indole-3-acetic acid (0.5 mg l−1) produced the best response. On subculture to the same medium, well developed shoots were obtained. Addition of 0.5% activated charcoal to the shoot initiation medium completely inhibited initiation of shoot primordia. The shoot buds could be rooted on medium supplemented with 0.1 mg l−1 indole butyric acid and plants transferred to soil.