Study On The Relationship Between The Resistance Of Different Tomato Varieties To ToMV And The Activities Of Oxidase

Twenty varieties or materials of tomato with different resistance were used for experiment. Through testing the reaction condition and pH of extract of POD and PPO, identifying the genetic relationship of twenty varieties by POD isozyme and testing the biochemical indexes of resistance to ToMV, the main results were showed as follows:1. Classification of resistance: According to the campestral resistance to ToMV and the analysis experimental data ,the resistance of twenty varieties were divided into three kinds:z(1)resistant variety, including Zhong-za No9. Zao Hong-bao. W2&2-4. Yellow-leaf tomato. Huang Sheng-guo and American tomato; (2)endurable variety, including saporous cherry tomato, California No1. Chuan-za No 10 and Oh-2-2-11; (3)susceptible variety, including L-402, Jin-ke Hong-mei, Big red tomato 903, California No4, Gai-liang America tomato, Bao-dao Ju-xing, Bao-da903. W262- Oh-2-2-6 and Jing-gang Big tomato No2.2. Relationship between activity of oxidase and resistance:Two weeks after inoculation with ToMV, the activity of several enzymes, including POD, PPO and PAL,in inoculated plants were higher than that in noninoculated ones. The more resistance the variety, the more changes of POD activity in inoculated plants. The more susceptible the variety, the more changes of PPO activity in inoculated plants. There was no evident regularity in the changes of PAL activity in all varieties.3. Relationship between isozyme and resistance: Colors of isozyme pattern of POD and PPO in inoculated plants were deeper than that in noninoculated ones; and the bands of POD and PPO were wider in inoculated plants than in noninoculated ones. There were 1-3 bands of peroxidase isozyme in resistant varieties more than those in susceptible ones, andthere were 1~2 bands of PPO isozyme in susceptible varieties respectively which were more than those in resistant ones.4. Genetic relationship: Likeness coefficients of twenty varieties changed from 0.54 to 1.00.They could be divided into four kinds of species when the likeness coefficient was 0.83.5. Optimal reaction condition: The activity of POD and PPO was the strongest when pH of PBS was 6.0 than the others. Suitable time of PPO reaction was 10 minutes. Using catechol as substrate, the count of OD was biggest when the wavelength was 398nm.6. Isolation effectiveness of gel with different concentration: 10% concentration of gel was suited for both of POD and PPO isozyme analysis. Clear enzyme band was helpful to do correlative analysis.To sum up, the changes of POD and PPO activities in tomato with different level of resistance had obvious trend after inoculation with ToMV. There were same trends to POD and PPO isozyme. So all of the biological changes of the two enzymes could be used for the auxiliary means of antivirulent breeding.