Relationship Between Toxin Produced By Tomato Leaf Mould And Resistance Of Tomato Varieties

The situation of the tomato leaf mould in the native area was observed and investigated in the study. The toxin produced by Cladosporium fulvum was tested and the activities of superoxide dismutase(SOD), peroxidease(POD), catalyse(CAT), and phenylalaine ammonia lyase(PAL) , H2O2Content, generation of active O2-, MDA contend relative electrical conductivity and resistant substances (sugar , soluble protein and Vc) in the seedlings treated by toxin of tomato leaf mould pathogen of tomato varieties with different resistance to tomato leaf mould were measured. Meanwhile, relations of those changes and resistance were analyzed. The results showed as follows:1. Occurring and damage of tomato leaf mould were more serious here. Eight varieties were identified. It was found zhongza No8 was a resistant variety, while 823 tomato was a susceptible variety.2. Seed germination, root growth and seedling growth and pathogonicity of leaves were inhibited by toxin. Sensibility of different varieties to toxin was different. At the same variety, the higher the concentration is, the higher the inhibition rates of seed germination, root growth and seedling growth are .3. After treated by toxin, changes of some protective enzymes in the resistant and susceptible varieties indicated that changes of SOD, POD and CAT were similar: the activities of enzymes were declined; resistant varieties displayed low range during the change. The activity of PAL was evaluated and evaluating range of resistant variety was higher than those of susceptible variety.4. The generation of active O2- which was evaluated in leaf, declined in root was higher in resistant variety than in susceptible variety. The Generation and content of H2O2 of resistant variety was earlier and higher than those of susceptible variety5. Membrane lipid peroxidation and relative electrical were evaluated and those change range of resistant variety were lower than those of susceptible variety6. Sugar, soluble protein and Vc content have close correlation with the resistance of tomato varieties. Resistant variety, compared with susceptible variety, had high contents of sugar, soluble protein and Vc content.7.There were changes in POD isozyme and soluble protein bands after treated by toxin. POD isozyme bands in resistant variety were more than in susceptible variety. Soluble protein bands were reduced, but bands of resistant variety were reduced less than those of susceptible variety...