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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: The data suggest that metabolism of auxins may be important for the persistence of a functional root nodule and the identity of these compounds was obtained by chromatography in other systems.
Abstract: [(3)H]Zeatin riboside was supplied to intact pea (Pisum sativum) plants either onto the leaves or onto the root nodules. When applied directly to nodules, approximately 70% of recovered radioactivity remained in the nodules, approximately 15% was detected in the root system, and 15% was in the shoot. However, when supplied to the leaves, little (3)H was transported, with approximately 0.05% of recovered radioactivity being found in the root system and nodules. On a fresh weight basis, nodules accumulated more (3)H than the parent root. In both types of studies, metabolites with an intact zeatin moiety were detected in root nodules.In all experiments, two-dimensional thin layer chromatography revealed that little (3)H remained as zeatin riboside in root or nodule tissue at the end of the labeling period. Nodules metabolized [(3)H]zeatin riboside to the following cytokinins/cytokinin metabolites: zeatin, adenosine, adenine, the O-glucosides of zeatin and zeatin riboside, lupinic acid, nucleotides of adenine and zeatin, and the dihydro derivatives of many of these compounds.Although a few small differences were observed, there were no major differences between root and nodule tissue in their metabolism of [(3)H] zeatin riboside. Furthermore, any differences between effective and ineffective nodules were generally minor.

80 citations

Journal ArticleDOI
TL;DR: A highly efficient and reproducible method of in vitro propagation using meristematic explants has been developed for castor by subculturing proliferating shoot cultures from various media onto the medium fortified with 0.5 mg/l BA.
Abstract: A highly efficient and reproducible method of in vitro propagation using meristematic explants has been developed for castor. Embryo axes and shoot tips were cultured on Murashige and Skoog (MS) medium supplemented with 0.5-10.0 mg/l of adenine, N6-benzyladenine (BA), kinetin (Kn), thiadiazuron (TDZ) and zeatin. TDZ (1.0-10.0 mg/l) gave the maximum number of shoots (37.8-40.0) from embryo axes, while BA (2.0 mg/l) was found superior to other cytokinins for obtaining the highest number of shoots (46.7) from the shoot apex. Adenine and Kn at all of the tested concentrations resulted in low proliferation rates from embryo axes. The carryover effect of the cytokinins was tested by subculturing proliferating shoot cultures from various media onto the medium fortified with 0.5 mg/l BA. There was no significant influence of the cytokinins on subsequent proliferation from the two explant types except for TDZ with embryo axes. The number of shoots from TDZ-habituated embryo axes ranged between 36.0 and 81.7, while it varied from 5.7 to 22.0 and 3.7 to 28.3 in axillary buds and embryo axes, respectively, on the other media. For elongation of shoots, gibberellic acid (GA3) (0.1-1.0 mg/l) was added to the medium supplemented with 0.2-0.5 mg/l BA. Incorporation of GA3 (0.1 mg/l) significantly enhanced the frequency of elongated shoots but drastically reduced the multiplication ability. Hence, proliferating shoot clusters were periodically transferred to the medium supplemented with 0.5 and 0.2 mg/l BA for further multiplication and elongation. Well-developed shoots were rooted on half-strength MS medium supplemented with 1.0 mg/l indole-3-butyric acid. The rooted plantlets were acclimatized with more than 60% success.

80 citations

Journal ArticleDOI
TL;DR: Life-long serial passaging of human skin fibroblasts in the presence of zeatin resulted in the prevention of cell enlargement, reduction of intracellular debris, prevention of actin polymerization, and enhancement of cellular ability to decompose hydrogen peroxide and to cope with ethanol and oxidative stresses.
Abstract: Our studies have shown that zeatin, (6-[4-hydroxy-3-methyl-but-2-enylamino]adenine), a cytokinin plant growth factor, has gerontomodulatory, youth preserving and anti-aging effects on serially passaged human adult skin fibroblasts undergoing aging in vitro. There were no immediate negative or toxic effects in terms of cell attachment, cell proliferation, cell survival, cytoskeletal organization, and cellular growth by treatment with zeatin concentrations between 1 and 200 microM. During long-term treatment, cells could be maintained throughout their replicative lifespan in the presence of 40, 80, and 200 microM zeatin, but the optimal concentration of zeatin's anti-aging and youth preserving effects was found to be 80 microM. Life-long serial passaging of human skin fibroblasts in the presence of zeatin resulted in the prevention of cell enlargement, reduction of intracellular debris, prevention of actin polymerization, and enhancement of cellular ability to decompose hydrogen peroxide and to cope with ethanol and oxidative stresses. Most importantly, anti-aging and beneficial effects of zeatin were observed without any induction of additional cell proliferation or an increase in the maximum proliferative capacity, thus ruling out any potentially harmful and carcinogenic effects.

79 citations

Journal ArticleDOI
TL;DR: Al3+-induced inhibition of root growth is preceded by significantchanges in CK content and composition and enhanced ethylene evolution, which indicates that CK can induce ethylene production, and the rapid increase in CK, particularly Z and dZ, may contribute to inhibition ofRoot-growth either directly or indirectly by affecting plant hormone homeostasis.
Abstract: The role of plant hormones in aluminium (Al3+)-inducedinhibition of root growth was investigated in roots of Phaseolusvulgaris L. cv. Strike. Changes in ethylene evolution and changes inthe content and composition of cytokinins (CKs), at intervals up to 150min after treatment with Al3+, were determined by gaschromatography (GC) and combined gas chromatography-mass spectrometry (GC-MS),respectively. Seedlings were cultivated in a continuously aerated nutrientsolution at pH 4.5 with and without Al3+. The growth rate ofAl3+-treated roots was significantly decreased after 360min. Ethylene evolution from excised root tips doubled after 15min of Al3+ treatment and reached a maximum 30min after treatment. Levels of CK nucleotides declined 60 to 80%after only 5 min of Al3+ treatment whereas the zeatin(Z) content increased six-fold. The increase in Z continued over the entire 150min-sampling period and reached a level 80 times higher than thatin roots not exposed to Al3+. These results show thatAl3+-induced inhibition of root growth is preceded by significantchanges in CK content and composition and enhanced ethylene evolution. Since CKcan induce ethylene production, the rapid increase in CK, particularly Z anddihydrozeatin (dZ), may contribute to inhibition of root-growth either directlyor indirectly by affecting plant hormone homeostasis.

79 citations

Journal ArticleDOI
TL;DR: A model of auxin-sugar interactions in ARF in carnation is proposed: cold storage brings forward root induction and sink establishment, both of which are promoted by the accumulation of Auxin but not of sugars, whereas high levels of sugars and probably also of cytokinins act as inhibitors.
Abstract: Cold storage of cuttings is frequently applied in the vegetative propagation of ornamental plants. Dianthus caryophyllus was used to study the limiting influences of auxin and sugars on adventitious root formation (ARF) in cuttings stored at 5°C. Carbohydrate levels during storage were modulated by exposing cuttings to low light or darkness. The resulting cuttings were treated (or not) with auxin and planted, and then ARF was evaluated. Carbohydrate levels in the cuttings were monitored and the influence of light treatment on indole-3-acetic acid (IAA) and zeatin (Z) in the basal stem was investigated. Dark storage for up to 4 weeks increased the percentage of early rooted cuttings and the final number and length of adventitious roots, despite decreased sugar levels in the stem base. Light during cold storage greatly enhanced sugar levels, particularly in the stem base where the Z/IAA ratio was higher and ARF was lower than observed in the corresponding dark-stored cuttings. Sugar levels in nonstored and dark-stored cuttings increased during the rooting period, and auxin application enhanced the accumulation of sugars in the stem base of nonstored cuttings. Auxin stimulated ARF most strongly in nonstored, less so in light-stored, and only marginally in dark-stored cuttings. A model of auxin-sugar interactions in ARF in carnation is proposed: cold storage brings forward root induction and sink establishment, both of which are promoted by the accumulation of auxin but not of sugars, whereas high levels of sugars and probably also of cytokinins act as inhibitors. Subsequent root differentiation and growth depend on current photosynthesis.

79 citations


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