关键词: 花生, 花生, 连作障碍, 根系分泌物, 自毒作用, 消减措施

Abstract: To lay the foundation for clarifying the biocontrol potential ability and developing the biological pesticide formulation of two Streptomyces albidoflavus, the stability and antifungal effect of the fermentation broth were analyzed. The antifungal activity on Fusarium oxysporum was detected by cylinder plate method, plate growth inhibition assay, mycelium dry weight method and spore germination inhibition method, and the membrane permeability was measured by conductivity test. The results showed that the fermentation broth of HD-103 and HD-109 had good stability under the condition of fluorescent light and low temperature, and could maintain antifungal activity at the original level of 80% after being treated with proteinase K, but had different sensitivities to organic solvents. EC50 values of the antifungal crude extracts of HD-103 and HD-109 were 97.9 μg/mL and 120.2 μg/mL on inhibiting F. oxysporum hypha growth, whileEC 50 on spore germination was 90.57 μg/mL and 83.36 μg/mL, respectively. Conductivity test indicated that the fermentation broth of two strains caused damage of plasma membrane of F. oxysporum. HD-103 and HD-109 had inhibitory effects on mycelia growth and spore germination of F. oxysporum, their fermentation broth had good stability，therefore they have the potential to develop into biocontrol agents.