生物农药与生物防治发展战略浅谈

ttttt目的ttttt探究红景天内生放线菌——变异链霉菌Hj3 (Streptomyces variabilis)的发酵条件、抑菌机制及对采后番茄早疫病的防治效果，为该潜在生防菌的开发利用奠定重要的理论与实践基础。tttttttttttttttttt方法ttttt采用菌丝生长速率法筛选Hj3抑菌物质产生的最佳培养液、接种量，利用正交试验设计探讨培养温度、培养转速、培养液初始pH值等条件，测定Hj3的生长曲线、抑菌物质产生曲线、Hj3抑菌物质对番茄早疫病菌产孢和孢子萌发的影响及对采后番茄早疫病的防治效果。ttttttttttttt结果ttttt在4号培养液(乳糖15 g、玉米粉4 g、K₂HPO₄ 0.8 g、KCl 0.2 g、CaCO₄ 1.6 g、水1 000 mL、pH 7)中接入8% Hj3种子液，28 ℃ 150 r/min震荡培养，在第4天时培养液中的活菌数最大，在第5天时Hj3发酵液的抑菌率达到最高；Hj3抑菌物质可明显抑制番茄早疫病菌孢子的产生和萌发，对采后番茄早疫病的防治也有一定效果。tttttttttttttttttt结论ttttt探讨出的发酵条件有利于Hj3抑菌物质的后续研究及应用，进一步明确其抑菌机制为Hj3的实际应用提供了更加充分的理论支持。tttt

Biological control of postharvest diseases of fruits

tttttPurposetttttIn order to explore the new potential biocontrol member Hj3 (Streptomyces variabilis), the fermentation conditions, inhibition mechanism and control efficiency of postharvest tomato early blight of antifungal substance produced by endophytic actinomycetes Hj3 from Rhodiola rosea were studied.ttttttttttttttttttMethodtttttUsing mycelial growth rate method, the best medium and inoculation dose were screened. The cultivated temperature, rotated speed, the initial pH value were discussed by the orthogonal experimental design. And the growth curve of Hj3, antifungal substance produced curve of Hj3, spore production, spore germination of Alternaria solani affected by fermentation broth of Hj3, and the control efficacy of postharvest tomato early blight were tested.ttttttttttttttttttResultstttttThe 8% seed medium of Hj3 was inoculated in the medium with lactose 15 g, corn meal 4 g, K₂HPO₄ 0.8 g, KCl 0.2 g, CaCO₄ 1.6 g, water 1 000 mL, pH 7. It was incubated in 28 ℃ and shaken with 150 r/min. In the fourth day the viable count was up to maximum, and the inhibition rate of Hj3 fermentation broth was the highest in the fifth day. The antifungal substance of Hj3 could inhibit the spore production and spore germination of A. solaniobviously, and control the postharvest tomato early blight well.ttttttttttttttttttConclusiontttttThe fermented condition avails the further study and application of antifungal substance produced by Hj3. And the inhibition mechanism and control efficacy of postharvest tomato early blight could support theoretically for practical application of Hj3.tttt