植物细胞对环境胁迫的适应性应答Ⅱ:过氧化氢是大蒜培养细胞应答氧化胁迫的灵敏指标

ADAPTIVE RESPONSE OF PLANT CELLS TO ENVIRONMENTAL STRESS Ⅱ:HYDROGEN PEROXIDE AS A SENSITIVE INDICATOR OF CULTURED ALLIUM SATIVUM L. CELLS IN RESPONSE TO OXIDATIVE STRESS

大蒜培养细胞暴露于冷、热、涝等典型的氧化胁迫条件下，或用活性氧引发剂甲基紫精和水杨酸处理细胞，均可导致过氧化氢急剧释放至胞外溶液中．但是，过氧化氢的暴发只是瞬时的，它们在５～１５ｍｉｎ内即达到峰值，随后逐减下降至基准水平．释出的过氧化氢之所以如此迅速消失，可能是因为自由基清除酶活力依时升高。

Exposure of cultured Allium sativum L. cells to some typical oxidative stress conditions, including chilling, heat shock and waterlogging or treatment of cells by generators of active oxygen species, methyl viologen and salicylic acid, led to an abrupt release of hydrogen peroxide into extracellular solution. However, the burst of hydrogen peroxide was transient and peaked within 5～15 min, and then dropped to a basal level. The rapid disappearance of the released hydrogen perexide might be due to the time coursed increase of free radical scavenging enzyme activities, in particular, the extracellular peroxidase activity.