牧草根际狗牙根平脐蠕孢菌的研究

The biological and culture characteristics of Bipolaris cynodontis (Marig) shoem from grass rhizomes

对陇东典型草地牧草根际分离获得的狗牙根平脐蠕孢的形态、培养性状和生物学性状进行了研究。结果表明，狗牙根平脐蠕孢菌分生孢子在10-40℃及pH值4．53～9．18均能萌发，适宜温度为20-30℃，适宜pH值为4．53～6．47，在液态水中萌发良好，且对光不敏感。麦根浸出液、羊粪浸出液可抑制孢子萌发，而土壤液和低浓度蔗糖液能促进孢子萌发；葡萄糖、乳糖、D-树胶醛糖、D-半乳糖、可溶性淀粉、甘露糖、胁木糖等碳源及硝酸钠、L-谷氨酸和亮氨酸等氮源对菌丝生长有促进作用，为该菌的良好碳、氮源；麦芽糖和氯醛糖等碳源及碳酸铵、尿素、精氨酸、氯化铵和甘氨酸等氮源对菌丝生长有抑制作用，为该菌的不良碳、氮源。该菌在各种碳、氮源培养基上菌落形态有差异。

Bipolaris cynodontis was isolated from grass rhizomes of the steppe grasslands. This study focused on the biological and culture characteristics of B. cynodontis. The temperature range for conidiospore germination of B. cynodontis was 10-40℃, and the optimum temperature was 20-30℃. Conidiospores could germinate well in water at pH 4.53-9.18 with an optimum pH of 4.53-6.47 and were not sensitive to light. Tests of four kinds of nutrient solution found that sheep dung suspension and wheat root suspension inhibited conidiospore germination while soil suspension and sugar suspension stimulated it. A temperature range of 10-40℃ was also suitable for hyphal growth, with the optimum hyphal growth occurring at 30℃. The hyphae grew fast on media with glucose, lactose, D-gummose, D-galactose, soluble starch, inannose or D-xylose as the C-source and with sodium nitirate, glutamic acid, or leucine as the N-source ,but they grew slowly on media with maltose, chloralose puriss as the C-source and with ammonium carbonate, urea and L-arginine, ammonium chloride or glycine as the N-source. There were clear differences in color, size and colony edge on these different C and N-sources.