稻生叶点霉生物学特性研究

BIOLOGICAL CHARACTERS OF PHYLLOSTICTA ORYZICOLA CAUSING RICE LEAF BLIGHT

稻生叶点霉（ＰｈｙｌｌｏｓｔｉｃｔａｏｒｙｚｉｃｏｌａＨａｒａ）菌丝生长和分生孢子器形成的最适温度为２５℃，而分生孢子萌发的最适温度为３０℃。菌丝生长、分生孢子器形成和分生孢子萌发的最适ｐＨ值均为６～７，但分生孢子萌发的ｐＨ范围很广，为１～１４。持续光照对菌丝生长和分生孢子萌发有一定的抑制作用，但光暗交替有些刺激效应。菌丝生长以查彼及马铃薯稻叶培养基为最好，但查彼等合成培养基上不形成分生孢子器。在麦粒和稻粒培养基上分生孢子器大量产生。在加有番茄汁、桔子汁、土壤浸出液及１％蔗糖液、１％葡萄糖液中，分生孢子萌发率一般达８０％以上，而在加有Ｖ８液和灭菌水中孢子萌发较差。病菌能利用多种碳源，其中以果糖、甘露糖、乳糖、蔗糖、淀粉、葡萄糖、麦芽糖为最好。５种氮源中，酪蛋白水解物和硝酸钾较好，而天冬氨酸、谷氨酸和硫酸铵较差。

The biological characters of the mycelial growth, pycnidial formation and conidial germination of Phyllosticta oryzicola Hara causing rice leaf blight are first reported in this paper. The optimum temperature for hyphal growth and pycnidial production was 25℃ while that for conidial germination was 30℃. The optimum pH values of mycelial growth, pycnidial formation and conidial germination were 6￣7, but the conidia could germinate in the condition of pH 1￣14. The continous lights had some inhibition on the hyphal growth and conidial germination, but the alternation of light and dark did some stimulation. The mycelia could grow well on Czapek′s agar and PDA plus rice leaf extract, but no pycnidia were formed on Czapek′s agar and Richard′s agar. A large number of pycnidia could be produced on wheat or rice grain media. The percentage of conidial germination was generally over 80% in the liquid media plus tomato juice, or soil extract, or 1% sucrose as well as 1% glucose, but rather low in the liquid plus V8 juice or sterilised water. The pathogem could use well many carbohydrates such as fructose, mannose, lactose, sucrose, amylose, glucose and maltose. Of 5 nitrogen sources used in the experiment ,the casein hydrolysate and potassium nitrate were better.