| The interactions of soybean and soybean cyst nematode (Heterodera glycines, SCN) were systematically studied by the tissue stain, paraffin-cut section, isoenzyme electrophoresis, polyamide thin layer chromatography, RAPD analysis and interorganismal genetics concept. The results as follow:1. The relationships of the different resistant soybean varieties and the population dynamics of H. glycines race 3 were studied. The population dynamics of SCN was influenced by different resistant cultivars. Development and female-male differentiation of SCN were different in the different resistant cultivars. The dormancy of H.glycines race 3 was also primarily studied. The supersession of the new and old root was related with the peak of the second stage juvenile(J2). The temporal and spatial dynamics of invasion for the SCN had closely related with the soybean root development.The results suggested that LiaoK89102 was showed against the invasion of H.glycines, PI90763, Franklin, Harbin small black soybean and Yingxian small black soybean were resistant to the development of SCN. The ratio of male-female was the highest (11.5:1) in the root of LiaodoulO, but the resistant variety Peking was the lowest (1:7.5). That showed the Peking was resistant to reproduction. The first peak of number of J2 emergence was at the 11 days after seedling, and second peak at 42 days after seedling. The cysts from soil could hatch in whole year under suitable condition, but it was different for the dormancy of eggs of cyst from different season.2. The different soybean cultivars existed different resistant mechanisms to the SCN. Under light microscope, the histopathological responses to the SCN showed that the adjacent necrosis and the lignification to the bodies of juveniles was occoured in the roots of resistant cultivars, such as PI437654, Peking, Harbin small black soybean and LiaoK89102, whereas the necrosis not found in the susceptible varieties.3. Defensive enzymes were stimulated after the infection of the J2 of SCN. The activity changes of defensive enzymes, include phenylalanine ammonia lyase(PAL), peroxidase(POD), catalase(CAT), polyphenoloxidase (PPO), superoxide dismutase(SOD) and Chitinaes, were studied. The malondialdehyde(MAD) and soluble proteins had different changes in the resistant and susceptible cultivars after infection of SCN.4. Infection of the J2 of SCN could induce functional proteins related resistance to H.glycines. The results suggested that proteins of SOD, POD and PPO increased in the root of both resistant and susceptible cultivars, but the induced proteins in resistant cultivars were much more than that in susceptible cultivars, and earlier occured in resistant cultivars than susceptible. The Franklinwas induced to produced a new band of POD isoenzyme; Peking and Franklin produced two new bands of PPO isoenzyme and a new band of PPO isoenzyme in LiaoK89102. It was very important to the intensive researches on the resistance-related proteins.5. Chitinase was an important pathogen-related protein in plant resistant to the diseases. A procedure to detect chitinase isoenzyme after polyacrylamide gel electrophoresis under native conditions and then stain in the gel was discussed. The results indicated that three chitinase isoenzyme bands were screened in the non-infection soybeans by SCN under UV light, a new chitinase isoenzyme band was produced in both resistant and susceptible cultivars after inoculating SCN. The activity of chitinase in resistant cultivars was more than that of in susceptible, and expressed earlier than susceptible cultivars.6. The relationships between the resistance to the SCN and the number of low weight molecular peptides/amino acids in soybean root exudation were studied by the method of polyamide thin layer chromatography. Fluorescence spots were named and grouped. Those spots of root exudation from different cultivars were analyzed through SPSS software. The results showed that the changes of low w... |
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