玉米及马齿苋叶片SOD活性诱导研究

以玉米幼苗及马齿苋作材料，通过甘露醇、H2O2、臭氧和强光等胁迫后，用NBT光化还原抑制法测定叶中SOD活性的变化。臭氧和强光能诱导玉米叶片SOD活性增加。0.5mol／L甘露醇处理玉米叶片12h，SOD活性上升，至48h后下降；在该甘露醇溶液中另外加入10^-2mol/L H2O2；处理12h后SOD活性基本不变。对玉米叶片单独用10^-2mol/L H2O2诱导，30min内SOD活性上升到最高值，随着处理时间的延长又逐渐下降。用耐强光、耐干旱的野生马齿苋作为材料，与玉米相比，其叶片SOD基础活性低于后者；若予以正午强光结合渗透胁迫2h，其叶中SOD活性增幅超过玉米，从种间比较的角度旁证了SOD在抗逆性中的作用。推测植物中存在比活性氧更为直接的物理诱导机制。

Study on the induction of SOD activities in maize and purslane leaves

The effects of environmental stress on the SOD activity in young leaves of maize (Zea mays L.)or purslane (Portulaca oleracea L.)Were investigated.The activity was assayed with NBT photochemical reduction inhibition method.O 3 and high light could induce SOD activity.The SOD activity increased in maize leaves treated by 0.5 mol/L mannitol for 12 h but dropped after 48 h.However, if 10 -2 mol/L H 2O 2 added at the same time,no activity change was observed.When treated by H 2O 2 alone,the activity reached the highest at 30 min,then decreased.Purslane,even though it tolerant to high light and drought in the wild,had basal SOD activity no higher than that of maize,while it augmented more significantly when treated by high light and high osmoticum.The role of SOD in stress tolerance was partly justified.The result indicated that direct physical induction mechanism might exist other than induction by ROS.