Physiological response of japonica rice to different time gradient treatment of colchicines

In this paper , the mature seeds of Xin Dao-18 which was one of japonica rice, were treated with four different time gradient of 0.15% colchicines, as follows:12h-, 241u 36hand48h. Changes of germination and swelling of root in seeds germination were examined, and antioxidant system activity including superoxide (POD), superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) in leaves of vegetative growth were measured. Also, the chlorophyll content and the content of soluble protein were tested at the same time. The result showed that the germination of Xin Dao-18 decreased gradually as the treatment time increased, but the swelling of root appeared increasing firstly and decreasing later correspondingly, the maximum was 74.01±1.01% at the treatment group 36h. Meanwhile, when the treatment time extended gradually, the POD and CAT activity characterized increasing before treatment group 36h, and declining after treatment group 36h; whereas the SOD activity decreased quickly when the treatment time changed from 12h to 48h. The MDA content and the content of soluble protein appeared decreasing firstly and increasing later, the minimum also appeared at the 36h. Furthermore, the chlorophyll content increased gradually as the treatment time extended. From these researches, we suggested that the proper treatment time of colchicines could cause the obviously biological effects on growth and development characteristics in inducing polyploid of the japonica rice.