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.

Effect of different cytokinins on axillary shoot proliferation and elongation of several genotypes of Sequoia sempervirens

Abstract: Five genotypes ofSequoia sempervirens were cultured in vitro. Stem segments of greenhouse-grown plants were disinfested and grown on a Wolter and Skoog (WS) medium without growth regulators for 4 wk. Newly developing shoots from axillary buds were then subcultured onto fresh media containing several different cytokinins at a concentration of 5µM each per treatment. The following cytokinin treatments were used: benzyladenine (BA), BA plus adenine hemisulfate,N-benzyl-9(2-tetrahydropyranyl) adenine (BPA), N6-[2-Isopentenyl]adenine (2ip), kinetin, thidiazuron (TDZ), and zeatin. Each genotype responded differently to tested cytokinins. The use of zeatin resulted in the highest number of shoots and the longest shoots for three genotypes ofS. sempervirens. In another experiment, shoots from three genotypes were grown on the same basal medium described above and supplemented with zeatin at six different concentrations (2.5, 5, 10, 15, 20, and 30µM). For all zeatin concentrations, significant differences among genotypes for shoot proliferation were observed. When all five genotypes were grown under three concentrations of zeatin (5, 10, and 15µM), differences among genotypes were observed for both shoot proliferation and shoot length. The influence of the culture medium on the overall micropropagation protocol ofS. sempervirens is discussed.

Identification d'une cytokinine par chromatographic en phase gazeuse à partir de cultures pures de Taphrina cerasi

Abstract: The ascomycete Taphrina cerasi (Fuck.) Sad., which induces malformations known as "witches’ brooms," when cultured in liquid media releases cytokinins. One of these, isolated from culture filtrates by ethyl acetate extraction, was identified as zeatin by paper chromatography, a biological test, and gas-liquid chromatography.

Low level expression of prokaryotic tzs gene enhances growth performance of transgenic poplars

Abstract: We modulated the level of a hormone gene expression in poplars using either 35S promoter (p35S) of cauliflower mosaic virus (CaMV) or aux promoter (pAUX) of A. rhizogenes. The transgenic poplars (Populus alba × P. tremula var. glandulosa), in which the bacterial trans-zeatin secretion (tzs) gene was attached either to the 35S promoter or to the aux promoter, were compared for their performance in tissue culture as well as in nursery. Northern blot analysis of total RNA probed with tzs coding region showed that the total tzs mRNA expression by p35S was approximately 200–300-fold higher than that driven by pAUX. In contrast, the cellular zeatin content of p35S-tzs transgenic poplars was merely 13-fold of those found in pAUX-tzs plants. Due to different levels of cellular zeatin levels, the two types of transgenic poplars showed different morphogenetic as well as growth responses. The p35S-tzs transgenic plants showed morphological characteristics typical of those treated with cytokinin in culture. These include multiple axillary shoot formation, thick stems, narrow leaves and absence of roots. In contrast, the pAUX-tzs plants had slightly higher cellular cytokinin levels than did control plants and showed a lower degree of cytokinin-related phenotypes, including a few axillary shoots in root-inducing media. Since p35S-tzs did not develop roots, only pAUX-tzs transgenic poplars could be transplanted to the nursery where they resumed a close-to-normal growth. Nevertheless, pAUX-tzs plants transferred to the nursery developed cytokinin-related phenotypes, including greater number of shoots, smaller leaves and slightly retarded growth in height, but with a high total biomass.

In vitro regeneration of Cyrtanthus species: ornamental plants with medicinal benefits

Abstract: Cyrtanthus (Amaryllidaceae) is a genus of perennial geophytes, endemic to the southern African region. Destructive and indiscriminate harvesting of bulbs for medicinal and ornamental purposes has led to intensive decimation of the populations of most of these species in their natural habitats. The aim of this study was to develop in vitro regeneration systems for Cyrtanthus contractus, Cyrtanthus guthrieae, and Cyrtanthus obliquus using twin-scale explants from mature bulbs. Twin scales from the three species were cultured on solid Murashige and Skoog (MS) medium with different concentrations of 6-benzyladenine (BA) and α-naphthaleneacetic acid (NAA) under 16/8-h light/dark conditions at 25 ± 2°C. The best shoot induction responses were obtained on MS medium containing 4.4 μM BA + 1.1 μM NAA (3.1 shoots/explant) for C. contractus and C. guthrieae and 6.7 μM BA + 2.7 μM NAA for C. obliquus. When the best shoot induction medium for each species was investigated for the effect of cytokinins on shoot organogenesis, using different concentrations of BA, kinetin (Kin), meta-topolin (mT), zeatin (ZT), and thidiazuron (TDZ), the medium that produced the best shoot induction for C. guthrieae also produced the highest number of shoots per explant, whereas the highest numbers of shoots per explant were obtained with 10 μM TDZ for C. contractus and 10 μM BA for C. obliquus. Superior quality shoots in all three species were obtained from MS medium supplemented with Kin and mT. Regenerated shoots were rooted successfully on half- and full-strength MS medium without plant growth regulators, transferred to organic soil mix, and successfully acclimatized in the greenhouse. The micropropagation protocols described provide rapid and cost-effective methods for in vitro propagation for application to the conservation and domestication of Cyrtanthus species.

An Improved 2-step Liquid Culture System for Efficient In Vitro Shoot Proliferation of Sundew (Drosera rotundifolia L.)

Abstract: An efficient procedure for in vitro shoot production of the medicinal plant sundew (Drosera rotundifolia L.) was developed. Of three cytokinins tested, zeatin (ZEA) at a concentration of 2 μM resulted in the formation of large numbers of adventitious shoots on leaf explants. A larger size of the small shoots was achieved by combining a 2-weeks preculture with ZEA (step 1: shoot induction) with a 5-weeks main culture without plant growth regulators (step 2: shoot elongation). Liquid media were superior to semisolid media: An average of 27.4 shoots per leaf explant, and 53.3 shoots per shoot explant were achieved. The 2-step culture system with liquid media permits a comparatively cheap micropropagation of sundew as well as in vitro biomass production, with potential for scale-up.