Temperature Effects on Starch Metabolism in Rice Leaf Sheaths during Heading Period
Date Issued
2009
Date
2009
Author(s)
Hsiao, Hou-Ting
Abstract
The temporal carbohydrate accumulated in leaf sheaths is an important carbon source during grain filling. Besides that, the temporal carbohydrate in leaf sheath also acculturate the grain filling rate when the rice subject moderate water stress. High temperature also acculturate the grain filling rate. In order to understanding the correlation between the grain filling rate and the carbohydrate supplying rate from leaf sheath . We analysis the temperature effects on starch metabolism in leaf sheath during heading period. My research was focused on the temperature effect on starch accumulation in leaf sheaths before heading and starch degradation in leaf sheaths at post-heading stage. The temperature that we treated on rice plants were 35/30℃, 25/20℃, and 15/13℃, respectively. Under the control condition, starch was rapidly accumulated in leaf sheaths during pre-heading period. Under lower temperature (15/13℃),the starch content in leaf sheaths was only 81.1% that in 25/20℃-treated rice plants (control plants), however the soluble sugar content was 171.8% that in control plants. On the other hand, high temperature treatment reduced both starch and soluble sugars content in leaf sheaths compared with control plants. We suggest that the plant lost a lot of assimilates under high temperature during treatment period. Since the GBSS and SSS activities were similar in leaf sheaths under different temperature treatment, the reduce of starch contents in high temperature-treated plants was not caused by starch synthase activities repressing. During post-heading period, the starch degradation rate is slower than that in 25/20℃, and the result showed that the amylase activities also didn’t higher than in 25/20℃. Therefore, the starch degradation rate in leaf sheath will not be accelerated by high temperature, and accelerate the carbon source supply to grain filling.
Subjects
rice
sink-source transition
high temperature
leaf sheath
starch
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-98-R94621104-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):7061afc63c3fe12e612620aa68ec2138