甜菜幼苗叶片保护酶系活性对低温的响应

Responses of Activities of Protective Enzymes to Cold Stress in Sugarbeet Seedlings

利用人工气候室模拟低温条件，对两个耐寒甜菜品种进行低温胁迫与恢复常温处理，以低温敏感品种为对照，研究了低温胁迫与恢复对甜菜幼苗叶片细胞膜透性及SOD、POD、CAT活性的影响。结果表明，甜菜耐寒品种在低温胁迫下膜透性破坏程度小，SOD活性先降低后增强，POD活性增强，CAT活性有所降低。说明甜菜幼苗在低温胁迫下先通过呼吸作用维持体内温度，再增强抗氧化酶活性来抵御活性氧伤害。POD活性可作为甜菜幼苗耐寒性的生理指标。

Experiments were conducted to study the effects of cold stress and recovery on membrane permeability and activitie of protective enzymes of two cold - tolerant varieties based on the artificial climate chamber with two cold- sensitive as control. The results show that cold -telerant smaller degree of penetration injuries, SOD activity represented a varieties represented lower MDA content and trend of rise first then fall, POD activity rose steadily but CAT fell. The resuhs suggested that sugar beet seedlings would maitain the intracellular temperature firstly via respiration, then strethen the activities of protective enzymes to defense ROS damage. POD activity could serve as the physiological index of evaluating the cold - tolerance of sugar beet seedlings.