The optimized condition for transformation triploid Chinese white poplar were co-cultured for 2 days and infected 10-15minutes with Agrobacterium concentration of OD600=0.3. It is benefit to obtain kmr shoots in the coculture medium without CoCl22H2O.

• 同时还发现共培培养基中去除微量元素的CoCl_22H_2O，转化频率由2.；9%25升高到6