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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: Foliar application of the cytokinins kinetin, dipbenylurea, benzylaminopurine and zeatin at the 1–10 ppm level has a general growth promoting effect on Mentha piperita, but not on Salvia officinalis and Lavandula vera, grown under controlled environmental conditions.

72 citations

Journal ArticleDOI
TL;DR: Leaf explants of tomato were cultured in vitro on Murashige and Skoog medium under controlled environmental conditions and large numbers of regenerated plantlets were transferred to pots and grown to mature plants.

72 citations

Journal ArticleDOI
TL;DR: A plasmalemma-enriched membrane preparation from etiolated soybean possesses an active ATP-dependent calcium pump which leads to calcium accumulation when assayed by the methods of Gross and Marmé.
Abstract: A plasmalemma-enriched membrane preparation from etiolated soybean (Glycine max L., cv. Wayne) hypocotyls possesses an active ATP-dependent calcium pump which leads to calcium accumulation when assayed by the methods of Gross and Marme (1978, Proc Natl Acad Sci USA 75: 1232-1236). Two-hour treatment of segments from the elongating zone of the hypocotyl with growth-promoting concentrations of indoleacetic acid gives up to 100 percent increase in the calcium transport activity. Conversely, similar pretreatment with zeatin or other cytokinins is inhibitory. In the meristematic and maturing zones of the hypocotyl, zeatin has the opposite effect of promoting calcium transport activity. One facet of cell-growth regulation may lie with hormonally mediated changes in efflux pumping of calcium.

71 citations

Journal ArticleDOI
TL;DR: Kinetic properties, as well as substrate specificity determined in cell cultures, are compatible with the hypothesis that members of the plant-specific purine permease family play a role in adenine transport for scavenging extracellularadenine and may, in addition, be involved in low-affinity cytokinin uptake.
Abstract: Cytokinins are distributed through the vascular system and trigger responses of target cells via receptor-mediated signal transduction. Perception and transduction of the signal can occur at the plasma membrane or in the cytosol. The signal is terminated by the action of extra- or intracellular cytokinin oxidases. While radiotracer studies have been used to study transport and metabolism of cytokinins in plants, little is known about the kinetic properties of cytokinin transport. To provide a reference dataset, radiolabeled trans-zeatin (tZ) was used for uptake studies in Arabidopsis (Arabidopsis thaliana) cell culture. Uptake kinetics of tZ are multiphasic, indicating the presence of both low- and high-affinity transport systems. The protonophore carbonyl cyanide m-chlorophenylhydrazone is an effective inhibitor of cytokinin uptake, consistent with H+-mediated uptake. Other physiological cytokinins, such as isopentenyl adenine and benzylaminopurine, are effective competitors of tZ uptake, whereas allantoin has no inhibitory effect. Adenine competes for zeatin uptake, indicating that the degradation product of cytokinin oxidases is transported by the same systems. Comparison of adenine and tZ uptake in Arabidopsis seedlings reveals similar uptake kinetics. Kinetic properties, as well as substrate specificity determined in cell cultures, are compatible with the hypothesis that members of the plant-specific purine permease family play a role in adenine transport for scavenging extracellular adenine and may, in addition, be involved in low-affinity cytokinin uptake.

71 citations

Journal ArticleDOI
TL;DR: When analysing the endogenous hormone concentrations in the various callus types generated in each genotype, it was found that only differences in the free IAA concentrations were associated with variations in the morphogenic properties of the calluses.
Abstract: Immature zygotic embryos of two wheat (Triticum aestivum L.) genotypes, known for their different ability to generate embryogenic callus, were used as initial explants to establish callus cultures. Embryogenic and non-embryogenic calluses were obtained from the competent genotype (`Combi'), while only non-embryogenic callus was produced by the incompetent one (`Devon'). The morphogenetic competence of each callus type was evaluated by transferring some segments to regeneration conditions. The endogenous hormone concentrations (free indole-3-acetic acid [IAA], abscisic acid [ABA], gibberellins 1, 3 and 20 [GAs], zeatin/zeatin riboside [Z/ZR] and N6[Δ2-isopentenyl] adenine/ N6[Δ2-isopentenyl] adenosine; [iP/iPA]) of the initial explants were determined by means of radio-immunoassay and showed that the only difference was the higher concentration of ABA found in the embryos of the most competent genotype; whose embryos showed a reduced rate of precocious germination. When analysing the endogenous hormone concentrations in the various callus types generated in each genotype, it was found that only differences in the free IAA concentrations were associated with variations in the morphogenic properties of the calluses. Higher concentrations of endogenous free IAA were typical of embryogenic callus cultures. It was also observed that a loss in the embryogenic competence of the calluses, due to a prolonged time of culture, occurred concomitantly with a reduction in free IAA concentrations, practically to the concentrations found in the non-embryogenic calluses.

71 citations


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