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.

Zeatin metabolism in Phaseolus: Enzymes and genes

Abstract: The metabolism of cytokinins has been examined extensively in plants, resulting in the identification of a number of metabolites (Letham and Palni, 1983; McGaw, 1987). The structural modifications of zeatin include formation of the nucleoside and nucleotide, N-glucosylation, N-alanyl conjugation, Oglycosylation, 0-acetylation, side chain reduction, and side chain degradation. Although the array of zeatin metabolites may differ widely between species and tissues, the genetic mechanisms involved in the conversions and their possible significance in plant development are largely unknown. There are, however, reports of the presence of different zeatin derivatives associated with developmental events controlled by Mendelian genes. The most interesting studies concern genes determining sex and fertility in Mercurialis which also affect qualitative differences in zeatin metabolites (Dauphin et al., 1979; Dauphin-Guerin et al., 1980; Champault et al., 1981). Other cytokinin-related genes include those controlling cytokinin autonomy in Phaseolus (Mok et al, 1980) and Nicotiana (Meins et al., 1983; Hansen et al., 1987), cytokinin resistance (Ashton et al., 1979; Blonstein et al., 1991) and overproduction (Wang et al., 1984; Futers et al., 1986) in tobacco and moss. However, it may be difficult to identify the DNA sequences involved in these genotypic variations since there are no apparent gene products directly associated with particular developmental events. Nevertheless, in Mercurialis, subtractive hybridization experiments have resulted in the isolation of sex-specific cDNAs (Hamdi et al., 1989; Louis et al., 1990) which may lead to the cloning of genes regulating male and female flower differentiation.

Tissue culture and ex-vitro acclimation of Rhododendron sp.

Abstract: The majority of Rhododendron species reproduce by seeds, but the cultured varieties the production of planting material is done vegetatively by greenwood cuttings or by grafting. Another, much faster and more economical propagation method is propagation by tissue culture. In this paper aspects regarding the micropropagation of this species are presented, respectively, initiation, multiplication and acclimation. For initiation two variants of media were used: V1-Murashige & Skoog and V2-Woody Plant Medium (McCown). The biologic material used for initiation is represented by 2-5 cm long young shoots taken from plants isolated in the greenhouse, juvenilized by repeated prunings. For multiplication, two variants of medium were used, also, V1’- Woody Plant Medium (McCown)+ 2 mg/l Zeatin and V2’- Woody Plant Medium (McCown)+ 5 mg/l 2-Ip.