Studies On Methods Of Spore Inducing For Phytophthora Capsici And Pepper Resistance Mechanism To Phytophthora Capsici

Pepper blight is a very serious disease of Capsicum in the world. In these experiments, the method of spore inducing for Phytophthora capsici was optimized by comparing the spore yield of P. capsici, which was cultured on five different mediums and with five different treatments. And we studied the change rules of soluble protein, malondialdehyde, peroxidase, catalase, phenylalanine ammonialyase and peroxidase isozyme bands which were in different resistant cultivars'leaves before and after infection. The results as follow:P. capsici was cultured on potato sucrose agar (PSA), carrot agar (CA), cornmeal agar (CMA), oatmeal agar (OMA), bean agar (BA) these five different mediums and with five different treatments of continual illumination, continual darkness, 4°C, 40°C, disconnected illumination respectively, and then compared the spore yield. The results showed that only 9 days culture, the sporangiums, which were induced in CA medium, with disconnected illumination treatment, was up to 11.05 sporangia in every eyeshot. Light was the necessary condition to sporangium formation. Medium types affected P. capsici sporangium yield and colony grow speed and colony shape in some degree. The sporangia which were induced from exuberance mycelia was much more than the weak ones.The results of resistance identification of Capsicum cultivars to P. capsici showed: in the 19 cultivars tested, A11 was highly resistant; A5, A9 and A15 were resistant, 2031,2056,E2,B3,A10, and so on, were medium resistant and E1, B2 and 2096 were susceptible.The experiment results showed that, the contents of soluble protein and malondialdehyde in the cultivars leaves went up firstly, and declined after they reached peaks. The more resistance of cultivars, the more content of soluble protein but the less content of malondialdehyde in the cultivars leaves.The changes of protective enzymes'activities were studied. The results showed that the activities of peroxidase (POD) in healthy leaves were significantly higher in resistant cultivars than those in susceptible ones. The activities increased both in resistant and...