中文摘要：

从核桃根部分离得到一株真菌,编号为G8,对其进行生物学观察,初步鉴定为葡萄壳小圆孢菌,并对其进行了复侵染研究,确定其为核桃内生真菌.对此菌株进行液体发酵,研究其发酵液及其萃取物的抑菌活性.结果表明：（1）发酵液的提取物对28种植物病原真菌均有不同程度的抑制作用,各萃取相粗提物在40mg·mL^-1时,乙酸乙酯萃取物的抑制效果最好,其次为正丁醇萃取物,萃余物最弱,但正丁醇萃取物对水稻纹枯、杨树溃疡、小麦雪腐病原菌的抑制率大于其它两相.（2）不同质量浓度的乙酸乙酯萃取物对11个病原真菌的活性实验结果表明：对苹果轮纹、苹果腐烂、小麦根腐、稻瘟4种病原菌的抑制率为100%,对苜蓿炭疽、小麦赤霉、番茄早疫、苹果炭疽和玉米小斑5种病原菌的抑制率表现出极显著差异,对玉米大斑和辣椒疫霉2种病原菌的抑制率无显著差异.（3）乙酸乙酯萃取物对5种细菌的抑菌试验表明,对蜡状芽孢杆菌和马铃薯芽孢杆菌2种细菌表现为抗药性,但不同质量浓度处理间差异不显著.

英文摘要：

A fungus separated from walnut＇s root has been named G8. G8 is an entophyte initially identified through biological observation and renewed invasion as Coniothyrium vitivora Mitura. After a fermentation of the fungus in liquid PDA, the antimicrobial activity of the fermentation products and their extracts was studied. The results show that the fermentation extracts all have restraining effect of different degrees on 28 pathogenic fungi; and at concentration 40 mg · mL^-1, the inhibiting effect of butanol, acetyl acetate, and residue goes from strong to weak, but the inhibition of the butanol extract is bigger than the other two phases on Thanatephorus cucumeris, Dothiorella gregaria and Monographella nivialis. An activity test of acetyl acetate extract at different concentrations on 11 pathogenic fungi shows that the inhibiting rate of the extract is 100% to Physalospora piricola, Valsa mall miyabe et. , Cochliobolus sativus and Magna porthe ; and that the inhibiting rate of Colletotrichum humtri folii, Fusarium gr Alternaria solani, Glomerella cingnlata, schr. et. and Bipolaris maydis at different concentrations is obviously different. An inhibiting effect test of acetyl acetate extract to 5 species of bacteria also indicates that Bacillus megateriurn and Bacillus mesenterius are resistant to drugs and the resistance is of little difference at different concentrations.