木霉菌对杨树树皮溃疡病菌拮抗作用的研究

应用哈茨木霉（Trichodema harziaunm)T88菌株和深绿木霉（T.atroviride)T95菌株分别与杨树烂皮病菌（Cytospora chrysosperma)和杨树水泡溃疡病菌（Dothiorella gregaria)进行了平皿对峙培养和载片对峙培养；并研究了两种木霉菌产生的挥发性代谢物对病原菌菌落的影响和其非挥发性代谢物对菌丝干重的影响；分别在光学显微镜和扫描电镜下观察了两种木霉菌的重寄生现象。结果表明：对峙培养中木霉菌T88和T95对两种病原菌均有明显的抑制作用。两种木霉菌均能产生挥发性代谢物质并不同程度地抑制病菌菌落的生长，在密闭条件下T95的抑制率最高达到80．30％。两种木霉菌产生的非挥发性代谢物质可以强烈抑制病原菌的生长、明显降低其菌丝干重，并具有热稳定性。在光学显微镜和扫描电镜下，可以观察到木霉菌的菌丝在病原菌的菌丝上平行或波浪式生长，并在其上产生钩状分枝、吸器或附着胞吸附于病原菌的菌丝上，或穿透病原菌的菌丝生长，或使病原菌的菌丝细胞生质浓缩和菌丝断裂。

STUDY ON THE ANTAGONISM OF TRICHODERMA SPECIES ON CANKER PATHOGEN FUNGI OF POPULAR

Trichoderma harzianum T88 and T. atroviride T95 in dual culture with Cytospora chrysosperma and Dothiorella gregaria were studied. Whether antagonists produced volatile antibiotic which inhibited the growth of pathogens and non volatile antibiotics which inhibited the dry weight of mycelium of pathogens were tested. Mycoparasitic activities of Trichoderma spp. were studied against two serious plant pathogens, Cytospora chrysosperma and Dothiorella gregaria by microscopy and scanning electron microscopy (SEM). Macroscopic observations of fungal growth in dual cultures revealed that T. harzianum T88 and T. atroviride T95 made hyphal contact with the pathogen within 3 days after inoculation, leading to the inhibition in pathogen growth. The volatile antibiotic which antagonists produced inhibited the growth of pathogen in varying degrees. The most inhibition rate reached 80.30% under the airtight condition. The non volatile antibiotics inhibited very strong the growth of pathogens. The dry weight of mycelium was evidently less than that of the control. The non volatile antibiotics were not sensitive to the heating. The microscopy and SEM investigations showed that T. harzianum T88 and T. atroviride T95 appeared to inhibit pathogens by mycoparasitism, with evidence of either parallel and waved growth, or by penetrating hyphal cells of pathogens by forming hooks, haustoria and appressoria like structures which invariably led to hyphal cell cytoplasm concentration and disruption.