水分胁迫下油梨幼苗活性氧代谢对光合作用的影响

Effect of Active Oxygen Metabolism on Photosynthesis of Avocado Seedlings under Water Stress

研究水分胁迫下油梨幼苗叶片活性氧代谢的动态变化及其对光合作用的效应，结果表明：水分胁迫前期（胁迫的最初２ ｄ），叶片含水量轻微下降，但Ｈ２Ｏ２和１Ｏ２迅速积累，ＡｓＡ和 Ｃａｒ含量降低，ＭＤＡ开始增加，光合速率下降。随胁迫程度的加深（３～１０ ｄ），叶片含水量显著下降，Ｏ２－累积并呈现高峰，清除活性氧的酶系统活性和非酶系统的含量明显降低，可溶性蛋白、光合色素大量降解，ＭＤＡ含量进一步提高，光合速率急剧下降并丧失（第６ｄ）。说明水分胁迫下油梨幼苗光合抑制与活性氧的积累有关。

The dynamic changes of active oxygen metabolism of the leaf of avocado seedlings under water stress and their effect on photosynthesis were investigated. The results showed that water content of the leaves decreased slightly at the beginning of the stress period (0-2 days). However, H2O2 and 1O2 were accumulated rapidly, AsA and Car contents reduced, MDA began to increase, and the photosynthetic rate went down. With stress (3-10 days), leaf water content was significantly reduced, O2- accumulated quickly with. peak appearance. the active oxygen scavenger content of enzyme system and non-enzyme system decreased evidently, soluble proteins and photosynthetic pigments degraded greatly, MDA content increased further, and the photosynthetic rate dropped sharply and disappeared at day 6. These results suggested that the photosynthetic inhibition in avocado seedlings under water stress be related to accumulation of active oxygen.