木霉对土传病原真菌的拮抗作用

ANTAGONISM OF TRICHODERMA HARZIANUM T82 AND TRICHODERMA SP NF9 AGAINST SOIL-BORNE FUNGOUS PATHOGENS

分别在体外及温室测定了筛选菌株哈茨木霉Trichoderma harzianum（T82）和Tricho-derma sp.（NF9）对土传病原真菌的拮抗作用。体外测定表明,木霉菌株T82和NF9对白绢病菌Sclerotium rolfsii,立枯丝核菌Rhizoctonia solani,瓜果腐霉Pythium aphanidermatum刺腐霉P.spinosum和尖镰孢Fusarium oxysporum在对崎培养中的拮抗系数分别为2或2～3和2。温室测定表明,用0、6%（W/W）T82麸皮培养物（107cfu/g）处理土壤。在人工接种白绢病菌,立枯丝核菌及瓜果腐霉20天后,黄瓜发病率分别比未用木霉处理的对照减少46、5%,28.4%和81。2%;用T82和NF9木霉孢子悬浮液（108cfu/ml）处理黄瓜种子,人工接种白绢病菌11天后,黄瓜成苗率分别比未用木霉处理的对照增加14%的20%。分别在光学显微镜和扫描电镜下观察到木霉T82对白绢病菌菌丝和菌核的重寄生以及木霉T82和NF9对立枯丝核菌菌丝的缠绕。穿入及寄生。作者认为重寄生可能是试验木霉菌株T82和NF9对白绢病菌和立枯丝核菌的主要拮抗机制。

The antagonism of selected Trichoderma isolates Trichoderma harzinum T82and Trichoderma sp.NF9 against some soilborne fungous pathogens were testedboth in vitro and in greenhouse.In vitro T82 and NF9 inhibited the hyphalgrowth of Sclerotium rolfsii,Rhizoctonia solani,Pythium aphanidermatum,Pythiumspinosum,and Fusarium oxysporum on dual culture with inhibition index 2 or2-3 and 2,respectively,In greenhouse experiments,soil treatment with 0.6%(W/W)T82 bran culture(10~7 cfu/g)reduced incidence of the diseases caused by Sclerotium rolfsii,Rhizoctonia solani,and Pythium aphanidermatum with46.5%,28.4% and 81.2%,respectively,20 days after inoculation with thepathogens;the seed treatment with T82 or NF9 spore suspension (10~8 cfu/ml)increased emergence percentage of cucumber seedling with 14% and 20%respectively,11 days after inoculation with Sclerotium rolfsii The hyperpara-sitism of T82 on hyphae and sclerotia of Sclerotium rolfsii and coiling andpenetration of T82 and NF9 mycelia on hyphae of Rhizoctonia solani in vitrowas observed by both microscope and SEM.lt is suggested that mycoparasitismis one of the most important mechanisms of antagonism for Trichodermaharzianum T82 and Trichoderma sp.NF9 against Sclerotium rolfsi and Rhizoctoniasolani.