Effects of light intensity on modulation of morphogenesis by cytokinins in Arabidopsis seedlings

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Publikace nespadá pod Ekonomicko-správní fakultu, ale pod Přírodovědeckou fakultu. Oficiální stránka publikace je na webu muni.cz.
Název česky Vliv světelné intenzity na změny morfogeneze semenáčků Arabidopsis za účasti cytokininů
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REKOVÁ Alena SOUČEK Přemysl BRZOBOHATÝ Břetislav

Rok publikování 2008
Druh Článek ve sborníku
Konference XII. pracovní setkání biochemiků a molekulárních biologů
Fakulta / Pracoviště MU

Přírodovědecká fakulta

Citace
Obor Genetika a molekulární biologie
Klíčová slova cytokinins; hypocotyl
Popis The participation of many environmental and hormonal cues notably influences the plant morphology. The hypocotyl is a very plastic organ, strongly influenced by both external and internal cues known to regulate cell elongation, such as light, hormones, temperature and gravity. The extension of the hypocotyl is regulated by a network of interacting factors as light and plant hormones. Light is one of the most important environmental factors for plants, as it provides photomorphogenetic signal. Cytokinins, as the members of the phytohormones, are the plant growth regulators that among others inhibit hypocotyl elongation in darkness. Conflicting results have been published regarding effects of cytokinins on hypocotyl elongation in light. The first reports concluded absence of any notable effects of cytokinins on hypocotyl elongation in Arabidopsis seedlings grown in light. Recently, stimulation of hypocotyl elongation by cytokinins was reported in Arabidopsis, however, the effect of cytokinins was found to be mediated by ethylene. We have been focused on the influence of light quantity (fluence) on hypocotyl elongation in transgenic A. thaliana seedlings (pOp-ipt-GUS::LhG4) with increased levels of endogenous cytokinins. At low fluence (lower than 20 umol photons m-2 s-1) hypocotyls of ipt overexpressing seedlings were significantly longer compared to controls. Interestingly, the effect was not influenced by inhibitors of ethylene biosynthesis and signaling providing the first evidence of a direct stimulation of hypocotyl elongation by cytokinins. Further, it was observed that the level of endogenous cytokinins play a role in the phenotype variability in ipt overexpressing plants. The increased cytokinin levels evoke several various abnormal phenotypes, on the one hand larger leaf rosette compared to control plants, on the other hand dwarfish plants.
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