牛筋草离孺孢生物学特性及代谢产物活性测定

对牛筋草离孺孢属(Bipolaris sorokiniana)NJ-08菌株的生物学特性及代谢产物除草活性测定结果表明：此菌株的菌丝体生长速度慢, 但产孢量大, 致病性强。菌丝体生长最适温度25°C, 致死温度是55°C/10 min, 最适pH值为8, 碳源以葡萄糖最佳, 供试氮源则不利于菌丝体生长。产生分生孢子最适温度25°C, 最适pH值为8, 碳源以葡萄糖最好, 氮源以硝酸钠产孢量最高。分生孢子萌发温度在20°C~35°C之间没有差异, 适宜pH值为5~7, 碳源以D-木糖的孢子萌发率最高, 氮源以蛋白胨的孢子萌发率最高, 不同处理间存在明显差异。NJ-08菌株产生的代谢产物作用于牛筋草, 可使叶片黄化或枯死, 代谢产物对指示植物及杂草如柱花草、地桃花、猪屎豆和辣椒的胚根胚芽生长都有明显的抑制作用, 抑制率均超过了90%, 显示出很好的除草活性。

Biological Characteristics and Herbicidal Activity of Metabolites Produced by Bipolaris sorokiniana from Eleusine indica

The biological characteristics of Bipolaris sorokiniana strain NJ-08 and herbicidal activity its metabolites was tested. The results showed that NJ-08 displayed excellent pathoginicity and high sporulation. The optimum temperature and pH for mycelial growth was 25°C and 8 respectively, the lethal temperature was 55°C maintaining 10 min, the glucose was the best among carbon sources for mycelial growth but all nitrogen source did not significantly promote mycelia growth. For sporulation, the optimum temperature and pH was 25°C and 8, the glucose was the best carbon sources and NaNO3 was the best nitrogen sources. For spore germination, the ranges were temperature of 20°C~35°C and pH of 5~7, while D-xylose was the best carbon sources and peptone was the best nitrogen sources. The metabolites produced by NJ-08 strain made the leaves of Eleusine indica yellow and wilting, and showed good herbicidal activity against the indicator plant and weeds such as Stylosanthes guianensis, Urena lobata, Crotalaria mucronata and Capsicum frutescens with the inhibition rate to radicel and embryo of above 90%.