冷藏期间水分胁迫对菠菜叶片衰老生理的影响

保水处理菠菜以低密度聚乙烯（LDPE）薄膜袋自然合拢不扎口包装,对照菠菜直接装在多孔塑料筐内,在RH80%、温度（2±1）℃下贮藏,研究冷藏期间大量失水（水分胁迫）对菠菜叶片叶绿素降解和活性氧代谢的影响。结果表明,冷藏期间对照菠菜失水很快,遭受严重的水分胁迫;而保水处理菠菜失水很少。与保水处理菠菜相比,水分胁迫加快了对照菠菜叶片叶绿素含量的下降速度,使超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性降低,其中CAT和APX活性降低速率超过SOD,促进了过氧化物酶（POD）活性的上升,但没有明显增加丙二醛（MDA）的积累。说明水分胁迫降低了采后菠菜贮藏期间活性氧清除酶的活性,导致氧化胁迫,从而加速叶绿素的降解和衰老。

Effects of Water Stress on Senescence Physiology of Spinach Leaves during Cold Storage

Spinaches were directly packed in porous plastic basket as the control, preserving-water-treated spinaches were packed in low density polyethylene film（LDPE） bag without sealed and stored at RH 80% and（2±1） ℃. Effects of water stress on chlorophyll degradation and activated oxygen metabolism in spinach leaves during cold storage were studied. The results showed that, during cold storage, the control spinaches lost water very quickly and suffered severe water stress, while the spinaches of preserving-water-treated groups lost water little. Compared to preserving-watertreated spinaches, water stress accelerated the decline of chlorophyll content of control spinach leaves, decreased the activities of SOD, CAT, APX and GR, and the activities of CAT and APX were decreased much more than SOD, and increased the POD activity, but there was no significant increase in MDA accumulation. The results indicated that water stress enhanced the imbalanced decrease in activated oxygen scavenging enzyme activity, leading to oxidative stress,and accelerated the degradation and aging of chlorophyll.