Topic
Zeatin
About: Zeatin is a research topic. Over the lifetime, 2467 publications have been published within this topic receiving 64092 citations. The topic is also known as: Zeatin & (E/Z)-zeatin.
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TL;DR: Comparison of the proteinbanding patterns in the dormant and non-dormant buds showed a slight difference in the number of protein bands, but a wide variation in their types, suggesting differences in the regulation of gene expression.
Abstract: Strawberry runners are characterized by the occurrence of a dormant bud followed by a consequent non-dormant bud. Dormant buds were found to contain relatively low levels of endogenous gibberellic acid (GA 3 ) and enhanced levels of abscisic acid (ABA), as compared with non-dormant buds. The lower contents of GA3 in the dormant buds were also accompanied by attenuated levels of auxin (IAA) and cytokinins (zeatin and benzyladenine). Exogenous application of GA 3 (50 ppm) to the latent buds could achieve 97% break of their onset of dormancy. Histological examination showed that the initial stage of bud formation was similar in the dormant and non-dormant buds. Thus, triggering the burst of a dormant bud by GA 3 treatment is assumed to occur in the second developmental stage. Comparison of the proteinbanding patterns in the dormant and non-dormant buds showed a slight difference in the number of protein bands, but a wide variation in their types. The results suggest differences in the regulation of gene expression, perhaps controlled mainly by ABA in the dormant buds and GA 3 in the active state. KEY WORDS: Abscisic acid, auxin, cytokinin, zeatin, benzyladenine, histology, PAGE-electrophoresis Egyptian Journal of Botany Vol.5 2003: 35-42
2 citations
TL;DR: The ratio of embryogenesis to organogenesis was found to be 25 : 75 and this ratio could not be effectively controlled by media using varying concentration of 2, 4-D, BA, kinetin, and zeatin and the processes of plantlet regeneration were observed after the plantlets were embedded in paraffin.
Abstract: Callus was initiated from mature seeds without the rinds of barnyard grass, Echinochloa oryzicola Vasing, on a modified Murashige and Skoog (MS) medium containing 2.0∼20.0 mgl-1 2, 4-D. The rate of callus formation was greatly improved with the addition of 4 mgl-1 tryptophan. Upon transfer to MS medium containing 6.0 mgl-1 of 2, 4-D, the calli were sustained in subcultures. The plantlets were regenerated under light on MS medium involving various hormone combinations of 2, 4-D and cytokinins. In the regenerated plantlets 55% were normal plants and 45% abnormal plants including albinos. The processes of plantlet regeneration were observed after the plantlets were embedded in paraffin. The ratio of embryogenesis to organogenesis was found to be 25 : 75 and this ratio could not be effectively controlled by media using varying concentration of 2, 4-D, BA, kinetin, and zeatin.
2 citations
Journal Article•
2 citations
TL;DR: Cytokinin activity in the leaves of intact plants was higher in plants grown at 18°C than in those grown at 21° or 24°C and in excised leaves of Begonia x chemantha Everett cv, an increase in cytokininactivity was observed during the first 4 days following leaf detachment, however, after the seventh day cylokininActivity decreased again.
Abstract: Changes in activity of endogenous cytokinin-like substances were examined in intact plants and excised leaves of Begonia x chemantha Everett cv. Prinsesse Astrid (Christimas Begonia) by means of the tobacco callus bioassay. Cytokinin activity in the leaves of intact plants was higher in plants grown at 18°C than in those grown at 21° or 24°C. In excised leaves, an increase in cytokinin activity was observed during the first 4 days following leaf detachment. However, after the seventh day cylokinin activity decreased again. This decrease was more profound in leaves exposed to 24°C than in those exposed to 18°C.
Treatment of detached leaves with gibberellic acid (2.8 mM) caused an increase in measurable cytokinin activity. This increase was more profound in the zones of activity which correspond with zeatin glucosides on paper and Sephadex LH-20 chromatography. Additional zones of activity appeared after Sephadex chromatography. These were of a more slow moving nature with elution volumes corresponding to Nb-(Δ2-isopentenyl)adenine and its derivaties. Water-treated control leaves had higher activity in the regions corresponding to zeatin and zeatin riboside.
2 citations
TL;DR: A brief overview of the crystal structure of MtN13 in complex with trans-zeatin, a naturally occurring cytokinin is presented and it is shown that this protein expresses in the outer cortex of the nodule at early stages of nodulation.
Abstract: Nodules are unique root organs of legume plants. Nodulation (nodule formation) is an extraordinary symbiotic process which eventually allows a plant to assimilate atmospheric nitrogen. The nitrogen-fixing bacteria that colonize the nodules convert molecular nitrogen N 2 into compounds suitable for plant metabolism. A class of plant hormones called cytokinins are known to affect the nodulation process. A small protein, Nodulin 13 from Medicago truncatula (MtN13), is expressed in the outer cortex of the nodule at early stages of nodulation. MtN13 belongs to class 10 of plant pathogenesis-related proteins (PR-10). PR-10 members have been shown to bind cytokinins. This paper focuses on the involvement of cytokinins in nodulation and presents a brief overview of the crystal structure of MtN13 in complex with trans-zeatin, a naturally occurring cytokinin.
2 citations