Effect of low temperature on the rice (Oryza sativa L.) root system at seeding stage [Philippines]
1988
Qiujie Dai (Jiangsu Academy of Agricultural Sciences (China))
The experiment was conducted at the International Rice Research Institute [Los Banos, Laguna, Philippines] to study the physiological and biochemical responses of rice root to low temperature stress. The result indicated a positive relationship between root oxidizing activity and dry matter production in rice seedlings. Root oxidizing activity in cold-tolerant variety was higher than in cold-susceptible one under chilling conditions, suggesting it could be used as one of the criteria for selecting cold-tolerant rice varieties. Where root oxidizing activity fell to about 2 mg alpha-NA/2 hrs/g dry root, dry matter production of rice seedlings stops and probably, this value was near the threshold for dry matter production. This activity for peroxidase was also related to the root oxidizing activity under low temperature so that peroxidase can be used as another parameter for selecting cold-tolerant varieties. Content of protein in rice roots increased after chilling treatment. It is suggested that the production of soluble protein in rice roots is one of the mechanisms of rice resistance or adoption to a low temperature stress. Severe chilling stress decreased the amount of DNA and RNA while moderate chilling decreased the content of RNA indicating a supression of transcription process.
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