Effect of Chilling on DNA Endoreplication in Root Cortex Cells and Root Hairs of Soybean Seedlings |
| |
Authors: | D Ste¸piński |
| |
Institution: | (1) Department of Cytophysiology, University of Łódź, Pilarskiego 14, PL-90231 Łódź, Poland |
| |
Abstract: | Relative nuclear DNA contents in cortex parenchyma cells in root segments of 3- and 7-d-old soybean seedlings grown at 25
°C and in plants grown for 3 d at 25 °C, and then for 4 d at 10 °C, were determined with cytophotometry. Measurements revealed
that in each variant the cortex cell nuclei with DNA content between 2C and 8C were in all the examined segments and nuclei
with 8C – 16C DNA appeared in higher parts of roots. However, in chilled plant cells the number of 8C – 16C DNA nuclei was
very low. Therefore, chilling inhibited endoreplication in comparison with plants grown at 25 °C for 7 d, and even reduced
endopolyploidy level as compared to the initial seedlings, i.e. 3-d-old plants. DNA contents in root hairs grown at 25 °C (control) and in root hairs emerged at 10 °C were also determined.
In controls 4C – 8C DNA nuclei predominated while in chilled plants an additional population of 2C – 4C DNA appeared. Thus
a reduction of DNA synthesis was brought about by low temperature. The occurrence of an intermediate DNA contents besides
those with full endoreplication cycles suggests the possibility of differential DNA replication. This suggestion seems to
be supported by the lack of 3H-thymidine incorporation into root hair nuclei at the examined developmental stage both in control and chilled root hairs.
The same number, but larger, chromocentric lumps in polyploid cortex cell nuclei of higher root zones, in comparison to meristematic
nuclei, suggests that endoreduplication process occurred.
This revised version was published online in July 2006 with corrections to the Cover Date. |
| |
Keywords: | DNA content Glycine max |
本文献已被 SpringerLink 等数据库收录! |
|