以白三叶草叶片为材料，应用柯赫氏法则印证了链格孢菌对白三叶的致病性，并在PDA培养基上，设温度为15、20、25、30、35、40 ℃，pH为5、6、7、8、9(25 ℃恒温培养)进行白三叶草链格孢菌菌落培养7 d。结果表明，25 ℃时菌落生长最快，平均直径为7.1 cm；pH为6时，菌落生长速度最快，平均直径为9.0 cm。

The application of Koch's postulates confirms the pathogenicity of A. alternata(Fr.) Keissler in Trifolium repens Linn of which leaves are used as test materials in the experiment. In PDA medium， at six different treatment temperature of 15、 20、 25、 30、35、 40 ℃， under the pH value of 5、 6、 7、 8、 9， A. alternate(Fr.) Keissler have been cultured for seven days at constant temperature. The result shows that under the treatment of 25 ℃， colony growth is the fastest and average diameter is 7.1 cm； and at pH 6 colony growth is the fastest and average diameter is 9.0 cm.

S541.2