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.

In Loquat (Eriobotrya japonica Lindl.) Return Bloom Depends on the Time the Fruit Remains on the Tree

Abstract: In loquat (Eriobotrya japonica Lindl.), the comparison of fruiting trees and defruited trees carried out covering a range of developmental fruit stages reveals a significant reduction in flowering due to fruit from its early stage of development, being higher when it changes color and becomes senescent, which coincides with the floral bud inductive period. This effect occurred both at the tree and at the shoot level. Furthermore, although current shoots almost always develop into panicles, those from fruiting trees develop fewer flowers, suggesting that fruit also affects at the floral bud level. In our experiment, the gibberellin concentration at the floral bud inductive period was significantly higher in bark tissues (periderm, cortex and phloem tissues) of fruiting trees, compared with defruited trees that tend to flower more. The lower concentration of IAA in the bark tissues of defruited trees also contributes to increase their flowering intensity. On the contrary, the zeatin concentration was higher. Accordingly, at bud burst, the IAA/zeatin ratio, an indication of effect on flowering, was significantly higher for fruiting trees. Some disruption in the nitrate reduction process in fruiting tree was also observed. The process of floral bud induction and differentiation was not associated with either reducing or translocating and reserve carbohydrate concentration. Hence, loquat flower intensity depends on the time the fruit is maintained on the tree. The intensity is affected indirectly, by reducing the number of shoots, and directly, by reducing the number of flowers per panicle, and these effects are linked to endogenous plant hormone contents.

Tissue culture and rapid micro-propagation from leaves and stems of kiwifruit (Actinidia chinensis cv. Hongyang).

Abstract: A stable and efficient rapid propagation system was established from the female Actinidia chinensis cv.Hongyang young leaves and stem segments with axillary buds in vitro.Leaves were cultured for the initiating of callus,proliferation of adventitious buds;and axillary buds were cultured for sprouting,multiplication and rooting.The results indicated that callus formation was easy and proliferation efficiency achieved 100% when explants from leaves were cultured on MS supplemented with 1.0 mg·L-1 zeatin and 0.1 mg·L-1 naphthylacetic acid(NAA).The average multiplication coefficient was 5.2,and the highest induction rate was 93.33%.The medium of MS supplemented with 1.0 mg·L-1 6-benzylaminopurine(6-BA) and 0.1 mg·L-1 NAA was optimal for sprouting of axillary bud,and the highest induction rate was 83.33%.The multiplication coefficient of adventitious bud was 4.5 in the medium of MS supplemented with 2.0 mg·L-1 6-BA,0.2 mg·L-1 NAA and 0.1 mg·L-1 gibberellic acid(GA).Moreover,the medium of 1/2 MS with 0.7 mg·L-1 indolebutyric acid(IBA) was good for rooting.

Cytokinin-Induced Mitosis in Cultured Explants of Helianthus tuberosus L. Tuber Tissue

Abstract: Freshly excised explants of H. tuberosus tuber parenchyma tissue were cultured for up to 42 h in aqueous solutions of 0.6 µM indole-3-acetic acid (IAA; 0.6 µM) or one of four different cytokinins (0.4 or 2.0 µM) in the absence of IAA. All phytohormone treatments were effective in inducing partially synchronous mitosis, but mitosis was not observed in control explants cultured in water alone. IAA induced mitosis earlier and in a greater proportion of cells than did any cytokinin treatment. In most cases, cytokinins were more effective at the higher concentration. The relative effectiveness of the different cytokinins appeared to be benzyladenine > zeatin ≥ kinetin > zeatin riboside. Microdensitometric measurements of relative nuclear DNA levels indicated that DNA synthesis had not occurred in control explants, but was induced by both IAA and cytokinins before the mitotic activity that was observed in the later stages of culture. These responses of freshly excised explants were compared to the effect of zeatin on IAA-induced mitosis in prewashed explants, in which zeatin increased the synchrony of IAA-induced mitosis but not the proportion of cells undergoing mitosis.