Topic
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.
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TL;DR: A second cytokinin, zeatin, has been identified by its chromatographic behavior and mass spectrum including chemical ionization mass spectrometry of its permethyl derivative.
Abstract: Gametophore-over-producing mutants of the moss, Physcomitrella patens, when grown in liquid culture export high levels of cytokinin into their culture medium. The cytokinin produced by these mutants is postulated to account for their peculiar phenotype, that of mosses treated with exogenous cytokinin. N6-(Δ2-isopentenyl)adenine, the major cytokinin, has been identified previously in two of these mutants (Wang, Cove, Beutelmann, Hartmann 1980 Phytochemistry 19: 1103-1105) and now in additional representatives. A second cytokinin, zeatin, has been identified by its chromatographic behavior and mass spectrum including chemical ionization mass spectrometry of its permethyl derivative.
62 citations
TL;DR: In this article, changes in the levels of cytokinins, gibberellins, and germination inhibitors during stratification of Acer saccharum seeds suggest that the breaking of dormancy is a phasic process.
Abstract: The present studies on changes in the levels of cytokinins, gibberellins, and germination inhibitors during stratification of Acer saccharum seeds suggest that the breaking of dormancy is a phasic process Stratification at 5 °C led to a marked increase in the butanol-soluble cytokinins after 20 d Further chilling resulted in a loss of cytokinin The majority of the detectable cytokinin activity co-chromatographed with zeatin Similarly, at day 40, acidic gibberellin-like substances increased and declined with further chilling A loss of acidic germination inhibitors was also detected during stratification The acidic fraction was shown to contain abscisic acid (ABA) by its behaviour on GLC and isomerization with ultra-violet light Determinations of endogenous levels of ABA by combined GLC and isotope dilution methods indicated a loss of 97-9 per cent ABA during stratification The data suggest that the breaking of seed dormancy at low temperature involves the initiation of an ordered sequence of events that include the changes in growth hormones necessary to determine the course of development for the removal of dormancy
62 citations
TL;DR: Histological investigation showed that zeatin-induced meristemoids originated mainly from wounding tissues, and that TDZ induced a high level of mitotic division resulting in several proliferation zones nearby the epidermis and outer cortical tissues.
Abstract: The relative importance of explant, cytokinin type, carbon source and gelling agent for annatto organogenesis was studied The best organogenic response, including adventitious shoot number and elongation, was obtained when hypocotyl segments and rooted hypocotyls were cultured onto MS medium supplemented with 456 μM zeatin, 876 mM sucrose, and 28 g l−1 Phytagel® Adventitious shoots derived from hypocotyl segments were less frequent and more difficult to elongate than those derived from rooted hypocotyls Thidiazuron (TDZ) promoted a higher organogenic response in rooted hypocotyls, resembling a rosette-like structure, but impaired shoot elongation Histological investigation showed that zeatin-induced meristemoids originated mainly from wounding tissues, and that TDZ induced a high level of mitotic division resulting in several proliferation zones nearby the epidermis and outer cortical tissues Rhizogenesis efficiency (rooting frequency and root number) was greater at the highest indole-3-butyric acid (IBA) concentration (50 μM) employed, although calli occurred at the basal end of shoots Eighty percent of rooted plantlets survived after acclimatization This optimized regeneration protocol may enable further development of an efficient genetic transformation protocol for this species
61 citations
TL;DR: Analogs of the cytokinins trans-zeatin and benzylaminopurine have been prepared by Heck coupling on 6-vinylpurines or Sonogashira coupling on six-halopurines as key-steps, and their cytokinin activity has been evaluated based on their ability to stimulate increased growth in radish cotyledons.
61 citations
TL;DR: A cytokinIn-autotrophic strain of tobacco callus contained cytokinin-active compounds with chromatographic mobilities on Sephadex LH-20 corresponding to ribosylzeatin, zeatin, and 6-Delta(2)-isopentenylaminopurine.
Abstract: A cytokinin-autotrophic strain of tobacco callus contained cytokinin-active compounds with chromatographic mobilities on Sephadex LH-20 corresponding to ribosylzeatin, zeatin, and 6-Δ2-isopentenylaminopurine. Zeatin, the apparent major cytokinin, was estimated to be present at a concentration of 10-4 μmol/kg of tissue. Cytokinin-autotrophic callus supplied with [14C]adenine produced radioactive components with the same chromatographic properties as zeatin and 6-Δ2-isopentenylaminopurine. These components were not obtained from cytokinin-dependent tissue supplied with [14C]adenine in the same manner.
61 citations