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.

Foliar Thidiazuron Promotes the Growth of Axillary Buds in Strawberry

Abstract: Strawberry (Fragaria × ananassa Duch.) can be easily propagated with daughter plants or through crown division, which are developed from the axillary bud at the axils of leaves. This study was conducted to investigate the effects of different cytokinins, auxins, and their combinations on the axillary bud growth in strawberry. Four cytokinins (6-benzyladenine, kinetin, zeatin, and thidiazuron (TDZ)) and three auxins (indole-3-acetic acid, indole-3-butyric acid, and naphthaleneacetic acid) at a concentration of 50 mg·L−1 were sprayed on the leaves three times in 10-day intervals. The expression levels of cytokinin, auxin, and meristem-related genes in the crowns were also investigated. The results showed that TDZ was the most effective hormone for the axillary bud growth, and also promoted plant growth. However, chlorophyll, soluble sugar, and starch contents in the leaves were lower after TDZ. TDZ activated the cytokinin signal transduction pathway, while repressing the auxin synthesis genes. Several meristem-related transcription factors were upregulated, which might be essential for the growth of the axillary buds. These results suggested that TDZ can improve the cultivation of strawberry, while further research is needed to explain the effect on phytochemistry.

A cytokinin-binding 70-kD protein is localized predominantly in the root meristem

Abstract: The contents of cytokinins (zeatin, zeatin riboside, zeatin nucleotide, and zeatin N9-glucoside), total protein, and a 70-kD cytokinin-binding protein (CBP70) were estimated in the root meristem and elongation zones of four-day-old etiolated maize seedlings. Earlier, it was shown that CBP70 is a cytokinin receptor involved in the hormone-induced activation of transcriptional elongation. A pair of monoclonal anti-CBP70 antibodies were selected; this permitted us to use a sandwich-type immunoenzyme analysis in combination with the streptovidin–biotin system, and this improved substantially the sensitivity of the CBP70 measurement. As calculated per cell, the elongating cells were enriched in all cytokinin forms, especially in transport cytokinins (zeatin riboside and zeatin nucleotide) as compared to the meristem cells, but the meristemic cell contained three times less total protein and two times more CBP70 than the cell in the elongation zone. The CBP70 concentration per milligram of total protein was six times higher in the cytosol of the meristemic cell as compared to the elongation zone. Predominant localization of the CBP70 in the meristem implies its involvement in the cytokinin control of cell division.

Formation of zeatin allylic phosphate by the microsomal fractions of bulb disks of Iris × hollandica Tub. and tubers of Helianthus tuberosus L.

Abstract: It is shown that in bulbous Iris zeatin originates from a nucleotide. This nucleotide is probably zeatin-allylic-phosphate, in which a phosphate group is attached to the isoprenoid side-chain of zeatin. The formation of zeatin-allylic-phosphate from t-zeatin and 8-[14C]-zeatin by the microsomal fractions of Iris bulb disks and Helianthus tubers was demonstrated. The responsible enzyme was partially purified. 5′-AMP was found to be a phosphate group delivering substrate. Adenosine and adenine inhibited the enzyme reaction. The significance of the results is discussed in relation to cytokinin biosynthesis and the occurrence of bud blast in Iris.

Influence of Zeatin on Wheat Regeneration from Immature Embryos

Abstract: Immature embryo culture of nine Croatian winter wheat genotypes were performed in order to determine the influence of zeatin, as an exogenous growth regulator, on regeneration capacity of callus and number of regenerated shoots. Immature embryos 0.5-1.5 mm in size were aseptically isolated and plated with the scutellum exposed on modified MS medium containing MS salts and vitamins supplemented with 2 mg/l 2,4-D (2,4-dichlorophenoxyacetic acid) and 30 g/l sucrose. For shoot initiation, calli were transferred on two different regeneration media: MSZ0 medium (MS salts and vitamins supplemented with 0.2 mg/l 2,4-D and 30 g/l sucrose) and MSZ5 medium (MS salts and vitamins supplemented with 0.2 mg/l 2,4-D, 5 mg/l zeatin and 30 g/l sucrose) and incubated at 26°C with 16/8 h light/dark photoperiod. Mean regeneration capacity of callus was higher on MSZ5 medium compared to MSZ0 medium (48.0% and 33.6% respectively). For all genotypes, except Lipa, regeneration capacity of callus was higher on MSZ5 medium. However, mean number of regenerated shoots was similar on MSZ5 compared to MSZ0 medium (1.6 and 1.3 respectively). The highest number of regenerated shoots per callus induced was found for genotype Žitarka (4.39), followed by genotypes Barbara (2.76), Lipa (2.61), line ZG1 (2.04) and Edita (1.67).