大豆连作障碍研究Ⅲ.海洋放线菌MB-97促进连作大豆增产机理

Obstacles of soybean continuous cropping Ⅲ.Mechanism of soybean yield increment by marine actinomyces MB-97.

海洋放线菌MB 97能在重茬大豆根际成功定殖 ,对克服重茬大豆连作障碍具有显著作用 :抑制大豆根际致害微生物 (DRMO)紫青霉菌的生长繁殖达 80 % ,减轻了土壤毒素的危害 ;防治因大豆连作而加重的土传真菌性病害如镰刀菌等引起的根腐病达 5 0 %以上 ;调节优化大豆根际土壤微生物区系 ,B/F值显著上升 ,使土壤由低肥力的“真菌型”向高肥力的“细菌型”转化 ;MB 97对大豆有生长刺激作用 .田间试验结果平均增产大豆 15 .2 % ,表明海洋放线菌MB 97是一株优良的植物根际促生菌 (PGPR) .

An isolate of marine actinomyces MB-97 identified as Streptomyces microflavus could successfully colonize in the rhizoshpere of soybean,and inhibit Penicillium purpurogenum, a soybean deleterious rhizospheric microorga-nisms. After applied MB-97, the ratio of bacteria/fungi in the rhizosphere of soybean was increased,and the soil became to be 'Bacterial type' from 'Fungal type'. The populations of P. purpurogenum were apparently suppressed about 80%, and the harm of toxins in soil was weak. The soybean root rot caused by soilborne fungi such as Fusarium was decreased 50%, and MB-97 could stimulate the growth of soybean seedlings. In field study,the mean yield of soybean raised by 15.2%,implying that Streptomyces microflavus was an effective plant growth-promoting rhizobacteria on soybean.