Study For The Related Analysis Of Physiological And Biochemical Mechanism In Chinese Cabbage And Cabbage

The brassica clubroot is a kind of worldwide disease which is caused by Plasmodiophora brassicae Woron and any cruciferous plants can be infected by the pathogen. It greatly decreases the yields and quality of cruciferous crop under appropriate conditions. The soil will be long-term carrier and no longer suitable for cultivation of cruciferous plants. In recent years, the brassica clubroot expands quickly in our country. Therefore, the disease had seriously hampered the development of cruciferous vegetables industry. The best way to prevent and control clubroot is to breed disease-resistant varieties. Simple and useful inoculation method is the basis of disease resistance breeding. At the same time, physiological and biochemical mechanism of resistance is also very complex. Changement of relevant physiological and biochemical index can be used as auxiliary method for resistant identification.In the research, we study the best indoor artificial inoculation method and inoculation concentration using different Chinese cabbage and cabbage varieties and analyzed the changement of related physiological and biochemical indexes before and after inoculation.In order to find out the differences between resistant and susceptible cultivars,and to provide the theoretical basis for disease resistance breeding and pathogenic mechanism on cruciferae vegetable. The results were as follows:1、Study of inoculation method of Plasmodiophora brassicae in the Chinese cabbage and cabbageTwo inoculation methods which were mixing resting spores of the pathogen with soil and irrigating spores to the soil were compared. The former can cause higher disease percentage and disease index. And the most suitable inoculation concentration is0.5gram mycorrhizal per gram soil is the most suitable inoculation concentration.2、 Study of related physiological and biochemical index of Chinese cabbage and cabbage clubroot(1) The soluble protein content:The resistant and tolerant varieties of Chinese cabbage contained higher content of soluble protein than that of control sample after inoculation, while the susceptible variety just on the contrary. But for cabbage, the soluble protein content of all varieties was reduced. So the soluble protein content can just be used as auxiliary means of the resistance identification for Chinese cabbage to clubroot after inoculation.(2) The soluble sugar content:All varieties of both Chinese cabbage and cabbage contained higher content of soluble sugar than that of control sample after inoculation. But the soluble sugar content of resistant variety went up and down than that of control sample. So the soluble sugar content can not be used as auxiliary means for the resistance identification to clubroot after inoculation.(3) The MDA content:At the beginning of inoculation, all varieties of Chinese cabbage and cabbage contained higher content of MDA than that of control sample. After then the content was below that of control sample. But the resistant variety had higher content than both tolerant and susceptible varieties from start to finish. Therefore the MDA content can not be used as auxiliary means for the resistance identification to clubroot after inoculation.(4) The autioxidant enzyme activities:For all varieties of Chinese cabbage and cabbage, after inoculation, the SOD activity was increased and negatively correlated with the disease resistance. The POD activity of resistant variety was relatively high both before and after inoculation. The PPO activity of resistant and tolerant varieties was higher than that of control sample and susceptible variety. Yet the change of CAT activity was unordered and haphazard after inoculation. To sum up, only the PPO activity can be used as auxiliary means for the resistance identification to clubroot after inoculation.(5) The isoenzymes①ompared with control sample after inoculation:About Chinese cabbage, for resistant variety, the isozyme bands of SOD, PPO and POD had no obvious change, while a new band appeared on the isozyme bands of CAT. For tolerant variety, the isozyme bands of SOD had no change and the isozyme band D of POD disappeared. At the same time, a new band and two new bands separately appeared on the isozyme bands of PPO and CAT. For susceptible variety, an additional band appeared on the isozyme bands of SOD and POD. While the isozyme bands of PPO and CAT had no change, but the denseness of one PPO isozyme band became lighter. About cabbage, for resistant variety, the isozyme bands of SOD had no change and the isozyme band A of POD disappeared but an additional band B appeared. Moreover,a new band appeared on the isozyme bands of PPO and CAT. For tolerant variety, the isozyme bands of SOD, POD and CAT had no obvious change, but the isozyme band B of PPO disappeared. For susceptible variety, the isozyme band B of SOD disappeared and a new band A appeared on the isozyme of POD, but the isozyme band B disappeared. Besides, an additional band appeared on the isozyme bands of PPO, but the jsozyme bands of CAT had no change.②Compared with different varieties after inoculation:The isozyme bands of SOD of Chinese cabbage had no change but for susceptible variety of cabbage, the denseness of isozyme band C of SOD became lighter. For all varieties of Chinese cabbage, the isozyme bands of POD were diverse from each other. An additional band B of the POD isozyme appeared in tolerant variety of cabbage relative to that resistant variety.While a new band C appeared relative to that susceptible variety. There was an additional band on the isozyme bands of PPO in resistant variety of Chinese cabbage relative to that tolerant variety and susceptible variety. But the isozyme bands of PPO of cabbage had no change. The denseness of one isozyme band of CAT in susceptible variety of Chinese cabbage became lighter. However, there was a new band on the isozyme bands of CAT in resistant variety of cabbage.In conclusion, the soluble protein content, the PPO activity, the POD isozyme and the POD isozyme may be used as auxiliary means of the resistance identification for Chinese cabbage to clubroot after inoculation. The PPO activity, the POD isozyme and the POD isozyme may be used as auxiliary means of the resistance identification for cabbage to clubroot after inoculation.