Physiological And Biochemical Mechanisms Associated With Abiotic Stress Tolerance In Two Rape Seed Varieties (Brassica Napus)

For the great economic loss of reduced crop quality and yield caused by environmental stress, it is of vital significance to understand plant resistance mechanism and cultivate new varieties with high resistance. In this paper, the behavior of isozymes of esterase, peroxidase, catalase ,PPO and superoxide dimutase, as well as the protein, proline and soluble carbohydrates of two spring rape varieties with different resistance was investigated. It is implied that the differences are probably related with physiological and biochemical mechanisms of different resistances of two spring rape varieties. Our results are as follows:1. In suitable growing condition, the rape variety AS-3 with higher resistance germinates earlier than the variety CON about 15 hours. Besides, PAGE patterns of isozymes of esterase and PPO of two rape varieties are evidently different, which indicates that the two rape varieties have different genetic backgrounds. The results of seed germination experiments indicate that the variety AS-3 has higher resistance than the variety CON under low temperature, salt and osmotic stress.2. After treated with low temperature (4℃), NaCl solution with four concentrations and -4bar PEG solution, PAGE patterns of isozymes of esterase, peroxidase, catalase ,PPO and superoxide dismutase indicate that the expressions and activities of enzymes of the variety AS-3 are higher than the variety CON.3. SDS-PAGE patterns indicate that under stress conditions expression of 38KDa polypeptide of the rape variety AS-3 enhanced and the result is opposite for the rape variety CON.4. Under normal and stress conditions, soluble carbohydrates, proline and soluble protein contents as well as peroxidase and esterase activities of the variety AS-3 are higher than that of the variety CON.