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: Gibberellin synthesis is considered to be a likely component of the mechanism underlying smoke-induced germination, and was found to be significantly higher in red light-treated seeds than in controls, and peaked after 100% germination was obtained.
48 citations
TL;DR: By expressing FsPP2C1 in Escherichia coli as a histidine tag fusion protein, this work has obtained direct biochemical evidence supporting Mg2+-dependent phosphatase activity of this protein.
Abstract: An abscisic acid (ABA)-induced cDNA fragment encoding a putative protein phosphatase 2C (PP2C) was obtained by means of differential reverse transcriptase-polymerase chain reaction approach The full-length clone was isolated from a cDNA library constructed using mRNA from ABA-treated beechnut ( Fagus sylvatica ) seeds This clone presents all the features of plant type PP2C and exhibits homology to members of this family such as AthPP2CA (61%), ABI1 (48%), or ABI2 (47%), therefore it was named FsPP2C1 The expression of FsPP2C1 is detected in dormant seeds and increases after ABA treatment, when seeds are maintained dormant, but it decreases and tends to disappear when dormancy is being released by stratification or under gibberellic acid treatment Moreover, drought stress seems to have no effect on FsPP2C1 transcript accumulation The FsPP2C1 transcript expression is tissue specific and was found to accumulate in ABA-treated seeds rather than in other ABA-treated vegetative tissues examined These results suggest that the corresponding protein could be related to ABA-induced seed dormancy By expressing FsPP2C1 in Escherichia coli as a histidine tag fusion protein, we have obtained direct biochemical evidence supporting Mg 2+ -dependent phosphatase activity of this protein
48 citations
TL;DR: Although elongation zone length differed among dwarf, control, and GA(3)-treated leaf blades, in all three treatments a transient increase in apoplastic peroxidase activity preceded a reduction in the segmental elongation rate in leaves.
Abstract: The relationship between apoplastic peroxidase (EC 1.11.1.7) activity and cessation of growth in maize (Zea mays L.) leaf blades was investigated by altering elongation zone length. Apoplastic peroxidase activity in the elongation and secondary cell wall deposition zones of elongating leaf blades of the maize inbred line B73 was used as a control and compared to leaves of the dwarf mutant D8-81127, a near-isogenic line of B73 unresponsive to gibberellins, and to leaves of B73 plants to which gibberellic acid (GA(3)) had been applied via root uptake. Elongation zone length was increased by treatment with GA(3) through an increase in cell number as well as increased final cell length. The shorter elongation zone of dwarf leaves occurred primarily through reduced final cell length. Although elongation zone length differed among dwarf, control, and GA(3)-treated leaf blades, in all three treatments a transient increase in apoplastic peroxidase activity preceded a reduction in the segmental elongation rate in leaves. A peroxidase isoenzyme with pI 7.0 occurred in the leaf elongation zone during growth deceleration in all three treatments, and its activity decreased as growth displaced tissue into the region of secondary cell wall deposition. Growth cessation for all treatments coincided with the first appearance of peroxidase isozymes with pIs of 5.6 and 5.7. Based on the activity of particular isozymes relative to growth and differentiation, the pI 7.0 isoenzyme is most likely to be involved in cessation of cell elongation, while isozymes with pIs 5.6 and 5.7 are likely to be active in lignification.
48 citations
TL;DR: The results indicate that gibberellins are released generally from the scutellum and induce hydrolytic enzymes equally on the dorsal and ventral sides of the grain.
Abstract: The α-amylase contents of the dorsal and ventral sides of the endosperm of barley grains increase approximately equally during germination. Aleurone tissue from all locations in the grain is equally able to make α-amylase in response to gibberellic acid, so the distribution of this enzyme reflects the distribution of endogenous gibberellins.
47 citations
TL;DR: Dormant and non-dormant embryos have respiratory quotients near unity supporting the hypothesis that starch degradation occurs before germination, and release from dormancy is associated with a shift in metabolism from the glycolytic pathway to the pentose phosphate pathway.
Abstract: The rates of oxygen consumption of dormant and non-dormant excised embryos of Avena fatua L. before germination are similar. Gibberellic acid (GA) treatment stimulates germination of dormant embryos without affecting oxygen consumption. Thus dormancy is not the result of restricted oxygen uptake. The fat content of dormant and non-dormant caryopses remains constant during germination. Dormant and non-dormant embryos have respiratory quotients near unity supporting the hypothesis that starch degradation occurs before germination. 6-Phosphogluconate dehydrogenase, a key enzyme of the pentose phosphate pathway, is present in dormant and non-dormant dry embryos but the pre-germination C6/C1 ratio of non-dormant embryos is markedly lower than that of dormant embryos, indicating a greater participation of the pentose phosphate pathway in the respiratory metabolism of non-dormant embryos. Release from dormancy is associated with a shift in metabolism from the glycolytic pathway to the pentose phosphate pathway. ...
47 citations