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.

Genetic Differences in the Enzymatic Regulation of Zeatin Metabolism in Phaseolus Embryos

Abstract: Hormones play a significant role in all phases of growth and development of higher plants. Although the site(s) of action of hormones are largely unknown, it can be postulated that rather precise regulatory mechanisms must exist to maintain a critical hormone balance in order for controlled development to occur. We have focused our research on cytokinin metabolism in Phaseolus with the objective of identifying genetic mechanisms regulating cytokinin metabolism and biosynthesis. A systematic approach was taken by screening for genetic variations of interest, followed by genetic and biochemical characterizations. This approach has been successfully applied to callus systems and a number of reports describing inter- and intra-specific differences have been published [1, 16, 17, 18, 19, 20, 21, 23]. In this paper we summarize recent findings concerning the genetic differences in zeatin (Z) metabolism occurring in immature Phaseolus embryos. The studies described here have led to the identification of a new Z metabolic pathway and the discovery of differential expression of cytokinin-specific enzymes in Phaseolus.

Cytokinins in cut carnation flowers. VII. The effect of zeatin and dihydrozeatin derivatives on flower longevity

Abstract: Dihydrozeatin, at 4×10−5 M, delayed the senescence of carnation flowers while tZ, at the same concentration, accelerated it. cis-Zeatin was ineffective. The DHZ derivatives as well as the Z derivatives gave responses very similar to those observed for the parent free bases. While additional experimentation with radiolabelled derivatives is clearly called for, the similarity between the responses observed for the respective derivatives and the free bases, suggests that in the carnation flower there is a great deal of metabolic interconversion.

Pistil induction by hormones from callus of Oryza sativa in vitro.

Abstract: This study describes the successful formation of floral organ pistil from the callus of pistil explants of Oryza sativa L. For induction of floral organs, different explants--including young embryo, lemma, palea and pistil--were used for callus induction with different combinations of N(6)-benzyladenine and 2,4-dichlorophenoxyacetic acid (2,4-D). High frequencies of callus formation from pistil and young embryo explants were achieved. Floral organs were induced after calli from pistils were transferred to medium containing both zeatin and 2,4-D. The morphological characteristics of the pistil-like organs are very similar to those formed in planta though with minor differences. Further histological study revealed that the in vitro pistil contains an ovule within its ovary. Furthermore, a pistil-specific gene, OsMADS3 used as a molecular marker for pistil identity, was expressed in the pistil-like organs as it was in pistils in the flower of the plant.

Hormonal Changes Associated with Vegetative Malformation of Mango (Mangifera indica L.)

Abstract: Malformed seedlings of mango showed lower mean content of indole-3-acetic acid, gibberellic acid and a higher mean content of zeatin, abscisic acid and ethylene than healthy seedlings.