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: Cold treatment enhanced ABA, GA3 and ZT concentration and effectively regulated IAA concentration to reach the maximum level at the end of dormancy release period in the primary shoot of bulbs under 4 °C treatment, Apparently, there is a relationship between ABA and I AA concentration and bulb sprouting.
Abstract: Dormancy in lily (Lilium sp.) bulbs is broken by a cold period of several weeks. Sprouting percentage, growth and flower quality are reduced when bulbs are partially released from dormancy. To understand the involvement of phytohormones in dormancy release in lily bulbs, the concentration of endogenous abscisic acid (ABA), gibberellic acid (GA3), zeatin (ZT) and 3-indoleacetic acid (IAA) was examined in the primary shoot, outer scale and root of bulbs of Oriental hybrid Lilium ‘Siberia’ during the dormancy release period. Cold treatment (4 °C) enhanced ABA, GA3 and ZT concentration in the primary shoot. GA3, ZT and ABA reached their maximum levels on the 14th, 49th and 63rd days of cold storage, respectively. IAA concentration remained at a constant level in the primary shoot of bulbs at 4 °C up to 21 d. Thereafter, it increased gradually up to the maximum level on the 84th day. In the outer scale of the bulbs, GA3 increased dramatically on the 7th day, then declined till the end of the 4 °C treatment. In the root, GA3 was at a higher level in the bulbs at 4 °C than at 25 °C treatment before 42 d. The ratios of phytohormone that promote plant growth to phytohormone that inhibit plant growth were higher in the outer scale of the bulbs at 4 °C than those at 25 °C treatment before 42 d. The ratios were lower in the primary shoot of the bulbs after 42 d of the 4 °C treatment than those at 25 °C. In conclusion, cold treatment enhanced ABA, GA3 and ZT concentration and effectively regulated IAA concentration to reach the maximum level at the end of dormancy release period in the primary shoot of bulbs under 4 °C treatment. Apparently, changes in ABA and GA3 concentration differ in the primary shoot, outer scale and root of the bulbs of lily. These changes act as multipurpose signals in the control of bulb dormancy release in the different tissues of the bulb and during the different stages of bulb development. Apparently, there is a relationship between ABA and IAA concentration and bulb sprouting. Key Words: bulb, dormancy, Lilium sp., phytohormone
3 citations
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TL;DR: In this article, the NH4OH fractions (Am-fraction) were combined and analyzed by micro-crystalline cellulose thin layer and gas liquid chromatographies, and the fraction separated by TLC for the bioassay of cytokinin revealed activities at Rf values 0.5 and 0.7.
Abstract: Immature fruits of Japanese pear, Pyrus serotina, were picked and homogenized with 70% ethanol. The homogenate was extracted with 70% ethanol three times and filtrated. The filtrate was concentrated, the residue adjusted to pH 8.4 with 1N NaOH and then extracted with n-butanol. The butanol phase was evaporated and aqueous extract of the residue was added to a Dowex-50(H+ form) column and eluted with water, 1N NH4OH and 5N NH4OH successively. Cytokinin activities in the three fractions were tested by tobacco(Wisconsin No. 38) pith callus assay. Cytokinin activities were detected in both 1N and 5N NH4OH fractions, but not in the water. Based on these results, the NH4OH fractions (Am-fraction) were combined and analysed by microcrystalline cellulose thin layer and gas liquid chromatographies. The fraction separated by TLC for the bioassay of cytokinin revealed activities at Rf values 0.5 and 0.7. Analyses of TMS derivative of Am-fraction by GLC gave four peaks. Mixture of the TMS derivative with that of authentic zeatin analyzed on GLC revealed that peak 2 coincides with zeatin, and peak 1 was considered to be dihydrozeatin.
3 citations
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TL;DR: The effects of 17-DMC on stem growth were manifested as the changes in stem hormonal balance, particularly, in a decrease in the contents of GA, zeatin, and IAA and an increase in the ABA content.
Abstract: The effect of 17-dimethylmorpholinium chloride (17-DMC), a quaternary ammonium salt, on stem growth and productivity of spring rape (Brassica napus L, cv Star), and on phytohormone content in stem tissues was studied We found that the effects of 17-DMC on stem growth (inhibition of linear growth, development of anatomical structure and mechanical properties) were manifested as the changes in stem hormonal balance, particularly, in a decrease in the contents of GA, zeatin, and IAA and an increase in the ABA content Seed weight increased due to the retarding effect of 17-DMC on stem growth and the promotion of silique and seed development
3 citations
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TL;DR: Cell-free extracts prepared from senescing leaves of Ginkgo biloba and callus of Glycine max had the capacity to metabolise applied zeatin and were responsible for most of the radioactivity recorded.
3 citations
01 Jan 2009
TL;DR: Regeneration of recalcitrant okra plants in vitro would permit their rapid propagation and also aid in genetic transformation and Agrobacterium infection and regenerated plants were successfully hardened in earthen pots after adequate acclimatization.
Abstract: Regeneration of recalcitrant okra (Abelmoschus esculentus [L.] Moench) plants in vitro would permit their rapid propagation and also aid in genetic transformation. Explants (hypocotyls, cotyledonary nodal meristems, cotyledons and shoot tips) were excised from okra seedlings that were grown aseptically in Murashige and Skoog (MS) basal nutrient medium. The explants were cultured on MS medium supplemented with auxins, cytokinins, and different auxin-cytokinin combinations. More organogenic callus was obtained on medium fortified with MS nutrients with low concentrations of 2,4-D (dichlorophenoxy acetic acid), NAA (�-n aphthalene acetic acid) and TDZ (thidiazuron), in combination. Shoots were produced on hypocotyls, cotyledonary nodes, and shoot tips, and calli were derived from leaf and cotyledon explants cultured in medium supplemented with BAP (6-benzylaminopurine) and TDZ. Both Kn (kinetin) and Zn (zeatin) proved ineffective in inducing either shoot buds or shoots. Roots were induced on elongated shoots using MS medium containing NAA or IAA (indole-3-acetic acid). Genetic transformation was carried out with Agrobacterium tumefaciens carrying the plasmid pBI121 with a selectable marker gene for nptII (neomycin phosphotransferase). Transformed cells were cultured on kanamycin (50 mg/L) and cefatoxime (300 mg/L). Proliferation of callus was achieved, with complete suppression of Agrobacterium. About 50-60% calli showed GUS (�-glucuronidase) expression, confirming transformation. Thus, genetic transformation of okra was successfully achieved by optimizing various parameters for regeneration and Agrobacterium infection. The regenerated plants were successfully hardened in earthen pots after adequate acclimatization.
3 citations