中文摘要：

将CaCl2诱导大肠杆菌建立感受态及其质粒的转化过程进行逐一分解,根据转化效率探讨了Ca2＋在各个步骤中的作用.结果发现,Ca2＋并不能永久性地改变细胞的结构和生理状态;细胞只有在Ca2＋存在下才能维持其摄取DNA的能力;在诱导大肠杆菌摄取DNA的过程中,Ca2＋主要是在转化步骤中起作用,转化前是否用Ca2＋处理或处理时间长短对大肠杆菌摄取DNA能力影响不明显.

英文摘要：

In this study, the exact point of Ca2＋ exerting its function was determined according to the transformation efficiency. The result showed that the structure and physiology of cell were not changed perpetually and the capa bility of absorbing extracellular DNA was sustained only when the Ca2＋ was present; the result also showed Ca2＋ played an important role during the process of transformation, but whether E. coli was treated with Ca2＋ or not and the duration of the treatment before the process did not cause obvious effect.