JXB Advance Access originally published online on April 23, 2007
Journal of Experimental Botany 2007 58(8):2023-2031; doi:10.1093/jxb/erm071
Published by Oxford University Press [2007] on behalf of the Society for Experimental Biology.
RESEARCH PAPER |
Role of DNA endoreduplication, lipotubuloids, and gibberellic acid in epidermal cell growth during fruit development of Ornithogalum umbellatum
o
ska
mierczak
pi
ski
Department of Cytophysiology, University of
ód
, 90-231
ód
, Pilarskiego 14, Poland
* To whom correspondence should be addressed. E-mail: kwiat{at}biol.uni.lodz.pl
Cytophotometry of individual nuclei was used to examine the level of endoreduplication in epidermal cells from the upper and lower parts of the ovary during Ornithogalum umbellatum flower and fruit development. An increase in DNA content from 24C to 28C in both parts of the ovary was observed, while the epidermal cell surface area grew about 6-fold and 15-fold in the lower and upper parts of the ovary, respectively. However, the correlation between mean epidermal cell size and ploidy was distinct during epidermis growth. Lipotubuloids became bigger in the upper than in the lower part during ovary and fruit development. In addition, more dynamic growth of the epidermal cells of the upper than of the lower part of the ovary was connected to the higher content of gibberellic acid. A hypothesis has been put forward that the role of DNA endoreduplication in epidermal cell growth was modulated by the function of lipotubuloids and the gradient of gibberellin.
Key words: Endoreduplication, gradient of gibberellic acid, lipid bodies, lipotubuloids, ovary, regulation of cell growth
Received 29 January 2007; Revised 12 March 2007 Accepted 12 March 2007