Journal Article

Intracellular energy depletion triggers programmed cell death during petal senescence in tulip

A. K. Azad, Takayuki Ishikawa, Takahiro Ishikawa, Y. Sawa and H. Shibata

in Journal of Experimental Botany

Published on behalf of Society for Experimental Biology

Volume 59, issue 8, pages 2085-2095
Published in print May 2008 | ISSN: 0022-0957
Published online May 2008 | e-ISSN: 1460-2431 | DOI: http://dx.doi.org/10.1093/jxb/ern066

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Programmed cell death (PCD) in petals provides a model system to study the molecular aspects of organ senescence. In this study, the very early triggering signal for PCD during the senescence process from young green buds to 14-d-old petals of Tulipa gesneriana was determined. The opening and closing movement of petals of intact plants increased for the first 3 d and then gradually decreased. DNA degradation and cytochrome c (Cyt c) release were clearly observed in 6-d-old flowers. Oxidative stress or ethylene production can be excluded as the early signal for petal PCD. In contrast, ATP was dramatically depleted after the first day of flower opening. Sucrose supplementation to cut flowers maintained their ATP levels and the movement ability for a longer time than in those kept in water. The onset of DNA degradation, Cyt c release, and petal senescence was also delayed by sucrose supplementation to cut flowers. These results suggest that intracellular energy depletion, rather than oxidative stress or ethylene production, may be the very early signal to trigger PCD in tulip petals.

Keywords: ATP; DNA degradation; intracellular energy depletion; programmed cell death; senescence; tulip petal

Journal Article.  7135 words.  Illustrated.

Subjects: Plant Sciences and Forestry

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