杨树溃疡病菌拮抗菌发酵液抗菌谱及稳定性研究

对杨树溃疡病菌拮抗菌ZJNU8990发酵液抗菌谱和稳定性进行研究，为发酵液中抑菌活性物质分离纯化提供一定理论依据。采用平板对峙法或杯碟法测定拮抗菌株ZJNU8990发酵液对7种植物病原菌的抑菌效果，表明该拮抗菌发酵液对番茄早疫病菌和小麦赤霉病菌具有较好抑制作用，对苹果腐烂病菌、水稻纹枯病菌和烟草赤星病菌具有一定抑制作用，但对白叶枯病菌和黄瓜枯萎病菌无任何抑制作用。以杨树溃疡病菌为指示菌，采用杯碟法测定发酵液的热稳定性、酸碱稳定性及光稳定性。结果表明: 拮抗菌发酵液在温度低于90℃时，抑菌效果稳定，121℃下则抑菌活性完全丧失；在酸性条件下，随pH值降低而小幅下降，而在碱性环境中，随着pH值增加而明显降低；经紫外光或自然光照射后抑菌活性略有降低。因此认为，杨树溃疡病菌拮抗菌ZJNU8990发酵液具有一定开发价值和应用前景。

The study of antimicrobial spectrum and stability of fermentation broth produced by antagonistic strain against Dothiorela gregaria#br#

The antimicrobial spectrum and the stability of fermentation broth produced by antagonistic strain against Dothiorela gregaria were analyzed， which could be a certain theoretical basis for separation and purification of the bacteriostatic components from the fermentation broth. The effects of ZJNU8990 fermentation broth on seven plant pathogenic fungi were tested by plate stand opposite culture method or cylinder plate method. The results indicated that it had the better antagonism on Alternaria solani and Gibberella zeae， and had a certain antagonism on Fusarium oxysporium， Rhizoctonia solani and G. zeae， but had no antagonism on Xanthomonas oryzae pv. Oryzae nor F. oxysporium. Dothiorela gregaria was used as the indicator bacteria， and the thermal stability， pH stability and light stability of fermentation broth was determined using cylinder plate method. The bacteriostatic activity of fermentation broth of antagonistic strain is stable below 90℃， but it complete loss under 121℃. The bacteriostatic activity decreased slightly with pH decrease under acid condition， and decrease significantly with the pH increases under alkaline condition. In addition， it also decreased slightly under UV light and natural light. So the fermentation broth of antagonistic strain had certain development value and application prospect．