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.

Plant tissue culture: A history

Abstract: The author has lived in the plant tissue culture history since its beginning and had the opportunity to discuss with all the pioneers

Adventitious shoot regeneration from cultured petal explants of carnation

Abstract: Adventitious shoot regeneration was compared among leaf, stem and petal explants of carnation (Dianthus caryophyllus L.) cv. Scania on MS medium containing different concentrations of 6-benzyladenine (BA) and α-naphthaleneacetic acid (NAA). High frequency regeneration was obtained only from petal explants on the media containing 5 to 10 μM BA with or without 5 μM NAA. Among the cytokinins tested, N-2-chloro-4-pyridyl-N′-phenylurea and N-1,2,3-thiadiazol-5-yl-N′-N′-phenylurea were more effective than BA, kinetin, N6-2-isopentenyl adenine and zeatin on regeneration from petal explants. Although, high frequency shoot regeneration was obtained from all petal explants harvested from various developmental stages of buds, a significant decrease in regeneration capacity was observed in the explants obtained from fully-opened flowers. High frequency shoot regeneration was also obtained from the petal explants of cvs. Coral. Lena, Nora and White Sim, and an interspecific cultivar Eolo using the method developed in this study.

Polyribosome Formation in Relation to Cytokinin-induced Cell Division in Suspension Cultures of Glycine max [L.] Merr.

Abstract: We have investigated the relationship between cell proliferation and protein synthetic capacity in a cytokinin-requiring strain of cultured soybean cells (Glycine max [L.] Merr. cv. Sodifuri, of cotyledonary origin) in suspension culture. When transferred to a defined medium lacking cytokinin, very little cell division or cell enlargement took place over the course of a 6-day culture period. Cells transferred to medium of the same composition, but containing 0.5 μm zeatin, exhibited rapid initial growth, with maximum mitotic activity occurring after 24 hours in culture, and a doubling of the cell population within the first 36 hours of the culture period. The polyribosomal RNA content of the cells decreased over the course of the first 24 hours of the growth cycle while the polyribosome to monoribosome (P/M) ratio increased. The increase in the P/M ratio was greater in the cytokinin-treated cells. This apparent relationship between cytokinin-induced cell proliferation and polyribosome formation was examined further. Polyribosome formation was stimulated when zeatin was added directly to cell populations which had been cultured for 24 hours in medium lacking a cytokinin. Transfer to fresh medium alone also stimulated polyribosome formation, whether this medium contained a cytokinin or not. The magnitude of transfer-induced polyribosome formation depended upon the initial cell density (number of cells/ml of medium). Regardless of the initial cell density and independent of the P/M ratios attained, the cytokinin-treated cell populations divided while the cytokinin-deprived cell populations did not. In vivo labeling with [35S]methionine and slab gel electrophoretic separation of sodium dodecyl sulfate derivatives of the labeled polypeptides demonstrated qualitative changes in the spectrum of proteins synthesized by the cytokinin-treated cells. These qualitative changes were independent of the cell density (and hence, independent of the P/M ratio) but they preceded cytokinin-induced cell division.

EFFECTS OF PACLOBUTRAZOL (PBZ) ON FLORAL INDUCTION AND ASSOCIATED HORMONAL AND METABOLIC CHANGES OF BIENNIALLY BEARING MANGO (Mangifera indica L.) CULTIVARS DURING OFF YEAR

Abstract: ABSTARCT The physiology of floral induction in mango is still controversial and thus further work is needed for a better understanding of reproductive physiology of this important fruit tree. The objectives of this study were to investigate the role of a gibberellins biosynthesis inhibitor, paclobutrazol on floral induction of biennially bearing mango during off year and to examine the possible correlated hormonal and non-structural carbohydrate changes. Three distinctly biennially bearing mango cultivars were tested for two years under North Sudan climates. Results indicated the advantage of paclobutrazol on inducing flowering of the biennially bearing mango cultivars, Miska, Mahmoudi, and Totocombo during off year. Similar trends of hormonal changes were observed during the floral induction period on the tested cultivars. More-specifically, the levels of cytokinins (zeatin (z) + zeatin riboside (zr) and isopentenyl Adenosine (i-Ado) + isopentenyl Adenine (i-Ade)), and to a less extent the levels of abscisic acid (ABA) generally showed trends of increase during the floral induction period, while those of gibberellins (GA1+3+20) and auxin (IAA) were decreased during the same period. Starch levels in most of the cases were increased by the paclobutrazol treatment. Moreover, sucrose levels were generally increased during the floral induction period. To close, possible roles for some of the tested hormones and nonstructural carbohydrates on mango flowering are probably implicated.