海域霉菌对植物病原真菌抗性的研究

Antagonism of Mold Strains Isolated from Bohai Ocean to Bipolaris maydis and Fusarium oxysporum

以玉蜀黍平脐蠕孢菌（Bipolaris maydis）和大豆尖孢镰刀菌（Fusarium oxysporum）为指示菌株，采用平板对峙培养法初步测定渤海海洋霉菌的抑菌活性，再用牛津杯扩散法对初筛获得的活性菌株的发酵液进行抑菌活性测定。结果表明，菌株67对玉蜀黍平脐蠕孢菌和大豆尖孢镰刀菌有很强的抑制作用，菌株32对玉蜀黍平脐蠕孢菌有较好的抑制作用。将菌株67在28℃，180r／min条件下发酵培养66h，生物量达到7．054mg／mL，在54～120h的发酵时间内，发酵液均具有抑菌活性，发酵96h时抑菌效果最明显，对F．oxysporum和B．maydis的抑菌圈直径分别为20．3mm和13．6mm。同时发现，菌株67发酵液的抑菌活性不仅与发酵时间有关，而且与发酵液的PH值相关，具有明显的抑菌活性的发酵液的pH范围为4．0～5．0。

Fusarium oxysporum and Bipolaris maydis were used as indicative strains,and antagonistic mold strain isolated from Bohai ocean are initially obtained by pairing culture on PDA plate. The antifungal activity of fermented liquid from antagonistic strains was further determined by Oxford cup diffusion means. The results of pairing culture showed that strain 67 could inhibit the growth of F. oxysporum and B. maydis, and strain 32 could inhibit the growth of B. maydis. But only the antifungal activity from strain 67 fermented liquid was observed. When the strain 67 was fermented at 180 r/min and 28℃, the maximum biomass of 7. 054mg/mL was achieved in 66h,and the maximum antifungal activity was detected in 96 h,the inhibiting zone diameter was 13.6 mm to B. maydi and 20.3 mm to F. oxysporum. Meanwhile it was founded that the antifungal activity from fermented strain 67 was related not only to fermented time,but also to fermented pH value. Fermented liquid of strain 67 at pH4.0-5.0 had obvious antifungal activity.