【摘要】 确定合适的诱变剂量是D-核糖生产菌紫外诱变育种的一个重要原则,用正突变率作为评价指标无法确定最适诱变剂量,为此提出新的评价指标——平均正突变幅度,给出了其定义及计算方法,并将其应用于D-核糖生产菌的紫外诱变中,得到在15 W紫外灯和距离25 cm条件下不同照射时间的平均正突变幅度,并结合致死率曲线确定20 s为最佳紫外照射时间.更多还原

【Abstract】 The use of appropriate mutagen dosage is important in ultraviolet (UV) induced mutation of D-ri-bose producing strain. But it was hard to find the optimal mutagen dosage when positive mutation rate was used as the evaluating index. So a new evaluating index-average positive mutation extent was proposed and its definition and calculating method were given. When it was used in UV induced mutation of D-ribose producing strain under the condition of 25 cm below a 15 W UV lamp, the value of average positive mutation extent of different irradiation intervals was got. Combining the average positive mutation extent with lethal rate curve, 20 s was found as the best irradiation time.更多还原