小麦全蚀病菌不同致病力菌株的致病特点

利用小麦种子根接种小麦全蚀病菌Gaeumannomyces graminis var．tritici，研究了不同致病力菌株的致病特点。结果表明，弱致病菌株可侵染小麦，但罹病过程缓慢，接种第5天仅在皮层观察到少量菌丝体，13天有少量菌丝进入中柱，中柱组织在菌丝侵入前褐变，未出现导管堵塞现象，也不能导致典型的黑根症状。强致病菌株接种第2天可侵入皮层，8天即进入中柱，并在寄主组织内产生大量菌丝体，致使寄主皮层组织和中柱细胞大量褐变和坏死，以及导管堵塞。

Research on pathogenic characters of different virulence isolates of wheat take-all fungi

The pathogenic difference between isolates with different pathogenicity of Gaeuman-nomyces graminis var. tritici was studied with seminal roots of wheat seedlings. The results showed that the isolates with low virulence invaded the root slower than those with high virulence. A few mycelia could be observed in the cortex 5 days after inoculation and infected the stele 13 days after inoculation. The stele became brown before mycelia infected and no occlusion of vessels was observed. They did not induce typical symptom such as black root. Meanwhile, the high virulence isolates invaded the wheat more quickly. They infected the cortex 2 days, entered steles 8 days and caused occlusion of vessels in the host root stele after inoculation.