Effects of temperature stress on ethylene synthesis and rice caryopsis development during grain-filling stage
Date Issued
2012
Date
2012
Author(s)
Lee, Ya-Ting
Abstract
Temperature stress impacts grain quality and yield in grain-filling stage of rice. Ethylene manipulation during heading stage of rice correlates positively with chalkiness. In this study, rice cultivar TK9 was used as experimental material. After flowering, the flowering rice plants were moved to growth chamber for temperature treatments (20, 25 and 35 oC) for 15 days. In order to understand the regulatory mechanism between ethylene and temperature treatments, GC was utilized to analysis the ethylene evolution rate in the temperature treatment phase. Mature grain quality and storage content and physiologic responses of the developing grain were investigated. Real-time quantitative PCR was further utilized as a tool to realize the responses of the gene expression involved in related physiological processes.
In appearance of the grain quality analysis, high temperature defected grain quality. Poor grain quality, grain weight reducing and lower storage contents were occurred by high temperature. Superior spikelets had higher grain weight and better quality than inferior spikelets. The percentage of sterility spikelets was the highest at low temperature treatment. In physiologic analysis, including chlorophyll, H2O2, and ATP assays, high temperature increased H2O2 accumulation and chlorophyll degeneration and also decreased ATP concentration, but low temperature had opposite results. Both high and low temperatures caused acidification and cell death. In ethylene evolution rate analysis, both high and low temperatures accelerated ethylene evolution peak, and inferior spikelets had higher amount of ethylene evolution than superior spikelets. In gene expression analysis, high temperature restrained the gene expressions of starch synthesis enzymes, protein synthesis enzymes, anti-oxidation enzymes and PDHA3, and it as well increased the gene expressions of ADH and PAO. Compared with high temperature, low temperature delayed the time of the gene expressions of starch synthesis enzymes and protein synthesis enzymes. Genes involved in ethylene synthesis and ethylene transcription factors all induced at the early stage of developing caryopsis under high temperature. Treatment of high temperature (35 oC) with 1-aminocyclopropane-1-carboxylate (AOA) increased the content of starch and protein, grain weight and the percentage of perfect grains. Treatment of normal temperature (25 oC) with 1-aminocyclopropane-1-carboxylate (ACC) decreased yield and the appearance quality. These results revealed that temperature stress influence physiological pathways by ethylene, and the inhibition of ethylene synthesis can improve the appearance quality and grain yield at the early grain-filling stage.
Subjects
ethylene
temperature stress
rice
caryopsis
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-101-R99621106-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):fa97fe93af3bcb957c8ac2f186c7db30