Abstract: The results show that the pretreatment in low-temperature for 6h can increase the callus formation ratio apparently,being 1.43 times higher than that of the control;the callus forming ratio is decreased along with the prolongation of the low-temperature time,but the callus forming ratio increases after 18h low-temperature treatment.The pretreatment of low-temperature for 30h can also increase the callus forming ratio by 1.41 times.