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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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Journal ArticleDOI
TL;DR: Cytokinins do not seem to act as positive effectors in the prefloral transition phase in tobacco shoot apices, and the differences in distribution at the cellular level may be indicative of a specific physiological role of zeatin in nuclear processes.
Abstract: This study considered cytokinin distribution in tobacco (Nicotiana tabacum L.) shoot apices in distinct phases of development using immunocytochemistry and quantitative tandem mass spectrometry. In contrast to vegetative apices and flower buds, we detected no free cytokinin bases (zeatin, dihydrozeatin, or isopentenyladenine) in prefloral transition apices. We also observed a 3-fold decrease in the content of cytokinin ribosides (zeatin riboside, dihydrozeatin riboside, and isopentenyladenosine) during this transition phase. The group concluded that organ formation (e.g. leaves and flowers) is characterized by enhanced cytokinin content, in contrast to the very low endogenous cytokinin levels found in prefloral transition apices, which showed no organogenesis. The immunocytochemical analyses revealed a differing intracellular localization of the cytokinin bases. Dihydrozeatin and isopentenyladenine were mainly cytoplasmic and perinuclear, whereas zeatin showed a clear-cut nuclear labeling. To our knowledge, this is the first time that this phenomenon has been reported. Cytokinins do not seem to act as positive effectors in the prefloral transition phase in tobacco shoot apices. Furthermore, the differences in distribution at the cellular level may be indicative of a specific physiological role of zeatin in nuclear processes.

122 citations

Journal ArticleDOI
01 Jul 1980-Planta
TL;DR: Radioimmunoassays for the quantitation of trans-zeatin and related cytokinins have been developed and, due to the high specificity of this assay, crude extracts may be used for analysis.
Abstract: Radioimmunoassays for the quantitation of trans-zeatin and related cytokinins have been developed. Antisera produced against bovine serum albumin conjugates of trans-zeatinriboside have a high affinity (Ka=2.4.10-11 M) for zeatinriboside and for zeatin, but show a negligible cross reaction to isopentenyladenosine (0.1%) and cis-zeatinriboside (0.4%), only a slight cross reaction to dihydrozeatin (1.7%), and no cross reaction at all to other purines, such as adenosine and related, compounds, was observed. The assays are sensitive and measuring ranges extend from 0.06–30 pmol (0.02–10 ng) of zeatinriboside. This has been achieved by employing as tracers immunoreactive zeatin derivatives with high-specific activity, (tritiated zeatinriboside-dialcohol: 8.37.1011 Bq mmol-1 and zeatinribosyl-[125I]tyramine: ca. 1.9.1013 Bq mmol-1. The detection limit is 40 fmol (15pg) for the assay employing the tritiated tracer, and assay reproducibility is high (variation coefficients of triplicates less than 5%). Several hundred assays can be completed in one day, and, due to the high specificity of this assay, crude extracts may be used for analysis. The course of zeatin levels in developing fruits of Lycopersicon esculentum cv. Moneymaker is given.

121 citations

Journal ArticleDOI
TL;DR: In this article, conditions for plant regeneration from explants of tomato (Lycopersicon esculentum) cv. were studied for optimizing transformation procedure and the best regeneration rate was obtained from cotyledon explants from 8-10-d-old seedlings on a modified Murashige and Skoog medium (1962) with 0.5 mg dm -3 zeatin and 0. 5 mgdm-3 indolylacetic acid.
Abstract: Conditions for plant regeneration from explants of tomato (Lycopersicon esculentum) cv. UC82B were studied for optimizing transformation procedure. The best regeneration rate was obtained from cotyledon explants from 8-10-d-old seedlings on a modified Murashige and Skoog medium (1962) with 0.5 mg dm -3 zeatin and 0.5 mg dm -3 indolylacetic acid. Tomato cultivars (UC82B, Castone, F1 Ferline, Monalbo) and a Lycopersicon peruvianum «CMV sel. INRA» were studied. The cultivar UC82B and the wild Lycopersicon species showed an efficient shoot regeneration potential. Early events in the transformation of tomato cotyledons were analysed using an Agrobacterium tumefaciens strain carrying a binary vector with an nptII (pnos) gene and a reporter GUS-intron (p35S) chimeric gene

121 citations

Journal ArticleDOI
TL;DR: Phytagar tissue culture grade proved superior to other agars tested, increasing bud induction frequency from 0-33% to 80–93% and eliminating explant hyperhydricity.
Abstract: Chile pepper (Capsicum annuum L.) plants were regenerated from cotyledon explantsin vitro in four major stages: bud induction, bud enlargement, shoot elongation, and root development. Bud induction medium contained 0.5 mg/L (2.9μM) indole-3-acetic acid and 2 mg/L (8.9 μM) N6-benzyladenine. Bud enlargement occurred, and an occasional shoot appeared when medium with 2 mg/L (6μM) gibberellic acid, 2 mg/L (8.9 μM) N6-benzyladenine, and 5 mg/L (29.4 μM) silver nitrate was used. Most shoots elongated after placement on a third medium without plant growth regulators or on fresh plates of bud enlargement medium. Incubations were for 2, 2, and 4 weeks, respectively, at 28.5°C and continuous light. Treatment with silver nitrate was necessary for multiple shoot production and elongation to occur in the third culture stage and was most effective when present in the second-stage medium but not in the bud induction medium. Sixteen to 26% of the shoots rooted in medium with 1 mg/L (5.4 μM) 1-naphthaleneacetic acid after 1 month. Additional shoots transferred to a second rooting medium with 0.1 or 1.0 mg/L (0.54 or 5.4 μM) 1-naphthaleneacetic acid developed roots, increasing the overall rooting efficiency to 70–72%. Most rooted shoots grew well and produced viable seeds when grown in the greenhouse. Other cytokinins tested for plant regeneration were zeatin and thidiazuron. Zeatin induced few shoots and fewer well-developed plants. Thidiazuron induced multiple shoots 4 months after culture began, but many were small and did not elongate further. Phytagar tissue culture grade proved superior to other agars tested, increasing bud induction frequency from 0-33% to 80–93% and eliminating explant hyperhydricity.

118 citations

Journal ArticleDOI
TL;DR: An efficient method has been developed for regeneration of complete plants via somatic embryogenesis in Corydalis yanhusuo (Fumariaceae), an important medicinal plant, using tuber-derived callus using somatic embryos to establish somatic embryo-derived plants.

118 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202333
2022103
202135
202034
201932
201848