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.

Therapeutic effect of cytokinin sequence application on virus-infected cattleya tissue cultures

Abstract: The study investigates the chemotherapeutic effect of plant growth regulators in eradicating mixed infection with Cymbidium mosaic (CyMV) and Odontoglossum ringspot viruses (ORSV) from Cattleya schonbrunnensis × C. leopoldii gutata. The experiment was designed to test a range of concentrations of 6-benzylaminopurine, kinetin and zeatin added to the basal medium on proliferating Cattleya mericlones. The results indicate that to eliminate CyMV from tissue cultures the best protocol for adding plant growth regulators was induction with 3.2 mg·l -1 kinetin added to modified MS medium and then further propagation on 0.2 mg l -1 zeatin. This treat- ment was advantageous in terms of micropropagation. Micropropagation on basal medium supplemented with 5.0 mg l -1 BA after induction with 0.5 mg l -1 zeatin also effectively eliminated CyMV from cultures of the Cattleya hybrid. Infection with ORSV virus persisted in all treatments.

Genetic transformation of chilli (Capsicum annuum L.) with Dreb1A transcription factor known to impart drought tolerance

Abstract: Chilli, an important commercial crop, is recalcitrant to in vitro regeneration. In the present study, an attempt has been made to optimize the in vitro regeneration of two chilli local cultivars, viz., G4 and LCA334, and transform G4 with a transcription factor dreb1A under the control of a desiccation inducible promoter rd29A, known to impart desiccation tolerance, using binary vector pCAMBIA 2301. Different phytohormones and their concentrations in MS medium were evaluated for in vitro response; 0.25 mg L -1 zeatin and 2 mg L -1 phenyl acetic acid (PAA) supported the highest regeneration rate (37.86%). Among the explants, cotyledonary leaf exhibited a higher (51%) regeneration response compared to that of hypocotyls (24.73%), and genotype G4 had better (33.80%) regeneration rate compared to LCA334. Rooting of the shoots was the highest in MS medium with 2 mg L -1 indole butyric acid (IBA) compared to other hormones. The presence of transgene was confirmed by polymerase chain reaction (PCR) and Southern blotting. The acclimatized transformants were grown in pots and screened for drought tolerance. Some of the transformants showed improved tolerance to drought by lower wilting compared to the control plants. The transformation and regeneration protocol described in the present study may help in optimization of transformation of chilli for agronomic traits of interest.

Plant regeneration from mesophyll protoplasts of Lactuca perennis

Abstract: Cultured protoplasts of young, unexpanded leaves of the wild lettuce, Lactuca perennis, divided to produce cell colonies in an agarose-solidified, modified MS medium with reduced levels of inorganic salts, together with 2,4-d, NAA and zeatin at 0.2, 0.1 and 0.5 mg 1-1 respectively. Organogenesis followed the initial transfer of protoplastderived colonies to modified MS medium with 2,4-d, NAA and zeatin (0.1, 1.0 and 0.2 mg 1-1 respectively) and then to full-strength MS medium with 6-BA and NAA (0.4 and 0.05 mg 1-1). Shoots were rooted on agar-solidified MS medium lacking growth regulators. Regenerated shoots were established ex vitro, 21 weeks after protoplast isolation.

Organogenesis in leafy spurge (Euphorbia esula L.)

Abstract: All parts of leafy spurge seedlings can be regenerated when isolated and placed onto B5 medium. One-centimeter isolated hypocotyl segments were tested successfully for their usefulness as a bioassay system by comparing the response of auxins, herbicides, and cytokinins. Indole-3-acetic acid (IAA) was the most effective auxin to stimulate root formation. IAA was effective whether the hypocotyl segments remained on the same medium up to 60 days, or the segments were transferred to basal media after 2 or 5 days (pulse treatment). Pulse treatments with the other auxins resulted in stimulation of root formation; continuous or 5-day pulses of higher concentrations of indole-3-butyric acid,α-naphthaleneacetic acid and especially 2,4-dichlorophenoxyacetic acid and picloram formed excessive callus instead of roots. Picloram did not stimulate root formation, whether the treatment was continuous or pulse-treated. No roots formed with continuous picloram at 0.1 mg/liter or greater, but transfer to basal media did result in root and shoot formation at about 50% of the number formed on the controls. Lesser picloram concentrations had no effect. Shoots formed readily on untreated (control) segments, but continuous treatment with all three cytokinins, kinetin, zeatin, and zeatin riboside, increased the numbers of shoots about equally. Root formation was inhibited by the cytokinins at the higher concentrations (0.1 to 0.2 mg/liter). With the exception of a 5-day pulse of 0.04 mg/liter IAA, the auxins did not stimulate shoot formation, but generally inhibited shoot formation, even in pulse-treated cultures.