Abstract: Trichoderma is a promising biological control agent which can be used to control a variety of plant diseases,and it can also be used as a heavy metal adsorbent. In the study,83 strains of Trichoderma spp. covering eight varieties were collected from the grasslands in Beijing. Of these,8 strains were further evaluated for their antagonistic capacity against Clarireedia homoeocarpa which causes dollar spots in various turfgrasses. T. harzianum 152-22,T. brevicompactum 192-49,and T. virens 192-45 strains showed better inhibition of the pathogen due to their stronger competition for space and nutrients in dual culture plate,and the inhibition of secretive non-volatile and volatile substrates. Additionally,the cadmium tolerance of these strains was also investigated by the sequential gradual technique (0~350 mg·L^-1). An increasing cadmium gradients in the culture medium inhibited the growth of Trichoderma,but T. virens 192-45 isolate was found to be more tolerant to cadmium toxicity and grow the best. Cadmium stress increased the sensitivity of the Trichoderma isolates to soil pathogen. In summary,T. virens 192-45 exhibited good tolerance of pathogen under cadmium stress in the grassland.

Key words: Grassland, Trichoderma, Clarireedia homoeocarpa, Biocontrol, Cadmium stress

摘要： 木霉菌是具有广阔应用前景的生防制剂，可用于多种植物病害的防治，也可作为重金属的吸附剂。本研究从北京多种草地类型中分离到83株木霉菌株。本研究对8种木霉菌进行了拮抗币斑病菌的平皿试验，其中哈茨木霉152-22、脐孢木霉192-49和绿木霉192-45菌株利用其对空间和营养的竞争能力以及分泌的非挥发性和挥发性物质，显著抑制了币斑病菌的生长。此外，采用梯度试验(0~350 mg·L^-1)研究了这些菌株对高浓度镉胁迫的耐受性。随着镉浓度的增加，虽然三种木霉菌的生长均受到一定程度地抑制，但绿木霉192-45菌株表现出较强的镉耐受能力。这说明绿木霉菌对镉胁迫和币斑病菌均具有较强抗性。综上所述，绿木霉192-45可以在镉富集和币斑病频发的复合胁迫草地中发挥至关重要的作用。

关键词: 草地, 木霉, 币斑病菌, 生物防治, 镉胁迫