Results showed : ( 1 ) cbt cell death in low tempratures is accompanied by characteristic changes , such as , reduced cell size , distorted nucleus , chromatin condensation and margination and cell ( cytoplasmic ) vacuolization ; cell mortality and ca2 * concentration increase along with time passed in low temperature . mitochondrial membrane potential and 02 increased at first , and then decreased . activities of sod decreased at first , followed by significant increasing and finally depressed 结果表明： ( 1 ) cbt在低温协迫下，细胞圆缩，细胞核变形，染色质浓缩且边位，细胞质空泡状；细胞死亡率随处理时间的增加而增加；细胞内钙离子浓度随处理时间延长而递增；线粒体膜电位差在低温处理早期急速上升，随后一直下降；细胞内超氧阴离子( o _ 2 ~ - )在低温处理前期出现高峰，接着呈下降趋势；细胞内sod活性在低温处理前期减弱，接着上升，然后持续下降。
