Studies On Physiological Mechanism Nd Molecular Markers In Tomato Resistant To Bacterial Wilt

Tomato bacterial wilt, a destructive disease, is caused by Ralstonia solanacearum intruded. It is spreading from Guangdong province to almost southern area in our country now. By now an effective approach, preventing tomato bacterial wilt, hasn't been found so that people will concern the study on tomato bacterial wilt more and more.1. To research the basic physiological mechanism in resistant tomato bacterial wilt, we inoculated respectively the resistant and susceptible tomato cultivar so that we could study different tomato cultivars of the dynamic changes in the activities of four enzymes with related to resistance. The results that the phenylanine ammonia lyase ( PAL ) activity of 'T51A', a resistant cultivar, were stronger than its control ( CK ) while 'T9230', a susceptible one, is the same as its control ( CK ),when they were infected by Ralstonia Solanacearum. The resistant cultivar has higher activity of superoxide dismutase ( SOD ) than its control (CK), which peak value was increased by 16. 12%. But the susceptible one is inferior to its CK, which peak value was decreased by 25. 14% than CK. The activity of Peroxidase ( POD ) and polyphenoloxidase ( PPO ) were no significant difference between resistant cultivar and susceptible cultivar. The capacities of resistant cultivar in inhibiting chlorophyll deterioration and maintaining higher carotenoid content were significantly stronger than those of susceptible cultivar.2. To search an effective approach to preventing tomato bacterial wilt, chitosan were sprayed in tomato inoculated with Ralstonia solanacearum, to study effect of chitosan on bacterial wilt disease and resistance mechanism. The results indicated that chitosan spray induced tomato resistance to bacterial wilt and reduced disease index. The relative cure effect of the treatment 3, in which chitosan was sprayed twice...