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.

Genetic mapping of gibberellic acid-sensitive genes for semi-dwarfism in durum wheat

Abstract: Semi-dwarf varieties in wheat associated with gibberellic acid (GA3)-insensitive height reducing genes have led to significant increases in yield but often fall below this potential because of poor seedling emergence after deep showing. Alternative semi-dwarf genes may have the potential to reduce plant height without compromising early plant growth. In durum wheat, bulk segregant analysis was used to screen microsatellite markers linked with the GA3-sensitive genes Rht14 in cv. Castelporziano, Rht16 in cv. Edmore M1 and Rht18 in cv. Icaro. Molecular marker Xbarc3-6A for Rht14, Rht16 and Rht18 showed significant polymorphic differences among DNA bulks for height classes. The genes Rht14, Rht16 and Rht18 were linked with Xbarc3 (11.7–28.0 cM) on the short arm of chromosome 6A and they appear to be allelic. Semi-dwarf genes on chromosome 6AS may potentially be used in breeding for improved establishment.

Gibberellin and CCC Effects on Flowering and Growth in the Long-day Plant Lemna gibba G3

Abstract: The application of gibberellic acid (GA(3)) to the non-rosette long-day plant Lemna gibba G3 at concentrations from 0.1 to 100 mg/l did not induce flowering on short days and inhibited flowering on long days at concentrations of 1 mg/l and higher. On both short and long days GA(3) concentrations above 1 mg/l caused a decrease in frond size and fresh and dry weight, but an increase in the rate of frond production and thus an increase in the # VF (number of vegetative fronds). Identical results were obtained when gibberellin A(7) was used instead of GA(3).The addition of the plant growth retardant CCC [(2-chloroethyl) trimethylammonium chloride] to the culture medium on long days resulted in almost complete inhibition of flowering at 10(-3) M. Vegetative growth was also inhibited to some extent. With CCC at 10(-3) M the simultaneous addition of GA(3) resulted in partial reversal of flower inhibition with 0.3 mg/l GA(3) being optimal. The inhibition of vegetative growth as measured by fresh and dry weight was also partially reversed by GA(3), but the threshold concentration for reversal of flower inhibition was at least 10 times lower than that for inhibition of vegetative growth.These results are interpreted as indicating that gibberellins are important for flowering in the non-rosette long-day plant L. gibba G3, but apparently are present in non-limiting concentrations on short days.

Dormancy induction of somatic embryos of Siberian ginseng by high sucrose concentrations enhances the conservation of hydrated artificial seeds and dehydration resistance

Abstract: In most plants, somatic embryos tend to germinate prematurely, a process that is detrimental to controlled plant production and the conservation of artificial seeds. We investigated the dormancy characteristics of Siberian ginseng somatic embryos induced simply by a high sucrose treatment, a treatment that enables the long-term conservation of artificial seeds following encapsulation and provides embryos with an enhanced resistance to dehydration. Early-cotyledonary stage somatic embryos were mass-produced by means of bioreactor culture. These embryos were then plated on medium supplemented with various levels of sucrose (1%, 3%, 6% or 9%) and allowed to mature. Subsequent germination of these embryos following the maturation period depended significantly on the sucrose level. At concentrations of 9% sucrose, none of the somatic embryos germinated after maturation, and none were recovered after being transferred to half-strength MS medium containing 2% sucrose. Gibberellic acid treatment was necessary to induce germination; other growth regulators such as auxins and cytokinins did not induce a response. Endogenous abscisic acid content in somatic embryos matured at 9% sucrose (487.8 ng/g FW) was approximately double that found in those matured at 3% sucrose (258.4 ng/g FW). This indicates induced dormancy in embryos under high osmotic stress. Alginate encapsulation of embryos facilitated the artificial induction of dormancy to extend the conservation period without germination. The induction of dormancy strengthened resistance to dehydration after the embryos were desiccated to 15% of their normal water content. Reduced chances of embryo survival during long-term desiccation were distinctly delayed in dormant embryos. These results indicate that the induction of dormancy in embryos is a promising application for synthetic seed production.

Genetic Analysis of the Role of Gibberellin in the Red Light Inhibition of Stem Elongation in Etiolated Seedlings

Abstract: Red light causes a reduction in the extension growth of dark-grown seedlings The involvement of gibberellin in this process was tested by screening a number of gibberellin synthesis and gibberellin response mutants of Pisum sativum L for the kinetic response of stem growth inhibition by red light Gibberellin deficient dwarfs, produced by mutant alleles at the Le, Na, and Ls loci, and gibberellin response mutants produced by mutant alleles at the La and Cry2, Lka, and Lkb loci were tested Extension growth of expanding third internodes of dark-grown seedlings was recorded with high resolution using angular position transducers Seedlings were treated with red light at a fluence rate of 4 micromoles per square meter per second either continuously or for 75 seconds, and the response was measured over 9 hours With certain small exceptions, the response to the red light treatments was similar in all the mutants and wild types examined The lag time for the response was approximately 1 hour and a minimum in growth rate was reached by 3 to 4 hours after the onset of the light treatment Growth rate depression at this point was about 80% Seedlings treated with 75 seconds red light recovered growth to a certain extent Red/far-red treatments indicated that the response was mediated largely by phytochrome The similar responses to red light among these wild-type and mutant genotypes suggest that the short-term (ie 9 hour) response to red light is not mediated by either a reduction in the level of gibberellin or a reduction in the level or affinity of a gibberellin receptor

Physiological Effects of Gibberellic Acid. X. The Release of Gibberellin-Like Substances by Germinating Barley Embryos

Abstract: Barley embryos, completely free from endosperm, were excised from germinating grain at various times and allowed to diffuse into an aqueous medium for varying lengths of time. At the end of this time, the embryos and ambient solutions were separately extracted. Gibberellin-like activity in the extracts was determined with the barley endosperm bioassay using seed from the same variety, harvest and treatment schedule as was employed for the embryo diffusion experiments. Gibberellin-like substances were released by embryos throughout the 60 hour germination period, though at no time during this period could sufficient activity be extracted from the embryos themselves to account for the observed release. Solvent partitioning and chromatography identified at least one major acidic component migrating at an Rf similar to that of GA(3).It is concluded that the endogenous gibberellin-like substance(s) originates within the embryo during germination, and that the release of this substance(s) is temporally consistent with, and quantitatively sufficient to account for the in vivo endosperm mobilization response syndrome. A gibberellin-like substance is undoubtedly the endosperm mobilizing hormone.