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 performance of immobilized growing cells of Gibberella fujikuroi P-3 was affected by the immobilization agent used, nature and age of cells, mycelial cell density, size of beads and inclusion of linseed oil.
Abstract: The performance of immobilized growing cells of Gibberella fujikuroi P-3 was affected by the immobilization agent used, nature and age of cells, mycelial cell density, size of beads and inclusion of linseed oil. The beads, prepared by using standardized procedures, could be used for 8 cycles without affecting productivity in semicontinuous culture. The rate of production of gibberellic acid was 0.58–0.66 mg/l/h. An inverted conical fluidized bioreactor, based on the design employed in continuous plant cell culture, was adopted. This bioreactor offers many advantages. The pigment produced by the fungus is not similar to bikaverin, norbikaverin and O-dimethylanhydrofusarubin, the known polyketides.
36 citations
TL;DR: The time course relationship of GA induced germination and amylase development is investigated in an attempt to find out if GA-induced germination is mediated by amylases production.
Abstract: Gibberellic acid is known to break dormancy of several types of seeds: (a) light-promoted seeds, such as Grand Rapids lettuce seed (Lactuca sativa L. var. Grand Rapids); (b) lightinhibited seeds, such as the seed of the honey-bee plant (Phacelia tanacetifolia Benth; (c) seeds requiring stratification (storage at low temperatures in a moist condition), such as the hazel nut (Corylus avellana L.); (d) seeds requiring after-ripening (storage at room temperature in dry condition), such as the wild oat (Avena fatua L.). Recent findings indicate that when dormant hazel nut seeds are soaked at 5 C for 28 days, which is a natural means of breaking dormancy, the gibbereilin-synthesizing mechanism is activated and that actual synthesis of gibberellins takes place when the seeds are transferred to a suitably higher temperature. Accumulation of GA results in germination (10). It has also been suggested that in the phytochrome-controlled germination of Grand Rapids lettuce seeds, the role of Pfr is to activate GA biosynthesis (8). One biochemical reaction known to be enhanced by GA is the synthesis of hydrolases (especially a-amylase) in the endosperm of cereal grains, such as barley (2, 9, 13). Since starch is a major food reserve in the cereal grains, its breakdown is generally assumed to be an essential process of germination. Many writers have implied that GA stimulates seed germination via amylase synthesis (1, 7, 12). Drennan and Berrie (5) compared the time course of amylase development in dormant and nondormant wild oats (Avena spp.). Their results indicated that both types of seeds contained traces of amylases. When dormant seeds were soaked, there was neither germination nor a change in the level of amylases. When nondormant seeds were soaked (in water), they germinated in 4 days and from the 6th day, amylase activity increased. Thus, they concluded that buildup of amylases is a postgermination phenomenon, and a lack of amylase synthesis must be eliminated as a possible cause of dormancy. We have investigated the time course relationship of GAinduced germination and amylase development in an attempt to find out if GA-induced germination is mediated by amylase production. The seeds of Avena fatua L. (wild oat) type Montana were obtained from Dr. G. M. Simpson of the University of Saskatchewan. These seeds were field-harvested in 1968 and stored at -15 C prior to use. Dry storage at low temperatures
36 citations
TL;DR: Preliminary studies with Agrobacterium show great promise for soybean transformation based on theregeneration protocol reported here, and the presence of 6-benzylaminopurine and thidiazuron in the medium exerted a synergistic effect.
Abstract: Soybean (Glycine max L.) plantlets were e?ciently regenerated from mature and immature cotyledons of?ve different genotypes by studying various parameters affecting regeneration. Green organogenic noduleswere induced at the proximal end, which subsequently differentiated into shoot buds on modi?ed MS(Murashige T. and Skoog F. 1962. Physiol. Plant. 15: 473-497) medium. The presence of 6-benzylaminopurine(BAP) and thidiazuron (TDZ) in the medium exerted a synergistic effect, in that regenerationeffciency was higher than for either cytokin alone. The regenerated shoot buds elongated and rooted onMS medium containing 0.29 lM gibberellic acid (GA3) and 2.69 lM a-naphthaleneaceticacid (NAA),respectively. Rooted plants were established in the greenhouse with 87% success and produced viable seeds.Preliminary studies with Agrobacterium show great promise for soybean transformation based on theregeneration protocol reported here.
36 citations
TL;DR: The sucrose reduction induced by PCB was effectively reversed by simultaneous GA3 applications, and the involvement of nonstructural sugars in shoot growth of citrus seedlings was studied.
Abstract: SummaryThe involvement of nonstructural sugars in shoot growth of citrus seedlings was studied in ‘Carrizo’ citrange (Citrus sinensis (L.) Osb. × Poncirus trifoliata (L.) Raf.) rootstocks by foliage applications of gibberellic acid (GA3) and paclobutrazol [(2RS, 3RS)-1-(4-chlorophenyl)-4,4-dimethyl-2-(1,2,4-triazol-lyl)penta-3-ol] (PCB) and subsequent determinations of sucrose, glucose, fructose, and starch. PCB inhibited length (21%) and dry weight (19%) of the stem, whereas GA3 increased both (79 and 27%, respectively) in the absence or presence of PCB. On a dry weight basis, GA3 increased hexoses (22.5 mg g−1) and starch (48.4 mg g−1) in shoots (control values were 14.7 and 35.4 mg g−1, respectively), and PCB reduced sucrose (43%) and increased starch (36%). The sucrose reduction induced by PCB was effectively reversed by simultaneous GA3 applications. In roots, GA3 did not modify the levels of the nonstructural sugars, while PCB enhanced the amount of starch (38%). On a per plant basis, GA3 (38.8 mg) ...
36 citations
TL;DR: No report of inhibition of fruit buds in apples has been found, although Hull and Lewis obtained no effect on flowering or vegetative growth from a single application of a spray of 100 p.p.m. of gibberellin.
Abstract: Bradley and Crane1 have reported inhibition of fruit bud formation by gibberellin in apricot, almond, cherry and plum; Hull and Lewis2 in peach and Griggs and Iwakiri3 in pears. Gibberellic acid also inhibits flower formation in Fragaria spp.4 and Kalanchoe blossfeldiana5. No report of inhibition of fruit buds in apples has been found, although Hull and Lewis2 obtained no effect on flowering or vegetative growth from a single application of a spray of 100 p.p.m. of gibberellin.
36 citations