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

D 2008

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

REKOVÁ, Alena; Přemysl SOUČEK and Břetislav BRZOBOHATÝ

Basic information

Original name

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

Name in Czech

Vliv světelné intenzity na změny morfogeneze semenáčků Arabidopsis za účasti cytokininů

Authors

REKOVÁ, Alena; Přemysl SOUČEK and Břetislav BRZOBOHATÝ

Edition

1. vyd. Brno, XII. pracovní setkání biochemiků a molekulárních biologů, p. 49-49, 1 pp. 2008

Publisher

Masarykova univerzita

Other information

Language

English

Type of outcome

Proceedings paper

Field of Study

Genetics and molecular biology

Country of publisher

Czech Republic

Confidentiality degree

is not subject to a state or trade secret

Organization unit

Faculty of Science

ISBN

978-80-210-4526-2

Keywords (in Czech)

cytokininy; hypokotyly

Keywords in English

cytokinins; hypocotyl

Abstract

In the original language

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.

Cite

REKOVÁ, Alena; Přemysl SOUČEK and Břetislav BRZOBOHATÝ. Effects of light intensity on modulation of morphogenesis by cytokinins in Arabidopsis seedlings. In XII. pracovní setkání biochemiků a molekulárních biologů. 1. vyd. Brno: Masarykova univerzita, 2008, p. 49-49. ISBN 978-80-210-4526-2.

@inproceedings{896914,
   author = {Reková, Alena and Souček, Přemysl and Brzobohatý, Břetislav},
   address = {Brno},
   booktitle = {XII. pracovní setkání biochemiků a molekulárních biologů},
   edition = {1. vyd.},
   keywords = {cytokinins; hypocotyl},
   language = {eng},
   location = {Brno},
   isbn = {978-80-210-4526-2},
   pages = {49-49},
   publisher = {Masarykova univerzita},
   title = {Effects of light intensity on modulation of morphogenesis by cytokinins in Arabidopsis seedlings},
   year = {2008}
}

TY  - CONF
ID  - 896914
AU  - Reková, Alena - Souček, Přemysl - Brzobohatý, Břetislav
PY  - 2008
TI  - Effects of light intensity on modulation of morphogenesis by cytokinins in Arabidopsis seedlings
PB  - Masarykova univerzita
CY  - Brno
SN  - 9788021045262
KW  - cytokinins
KW  - hypocotyl
N2  - 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.
ER  -

REKOVÁ, Alena; Přemysl SOUČEK and Břetislav BRZOBOHATÝ. Effects of light intensity on modulation of morphogenesis by cytokinins in Arabidopsis seedlings. In \textit{XII. pracovní setkání biochemiků a molekulárních biologů}. 1. vyd. Brno: Masarykova univerzita, 2008, p.~49-49. ISBN~978-80-210-4526-2.

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