硒对酥梨叶片衰老及抗氧化酶系统的影响

Effects of Selenium on Leaf Senescence and Antioxidase System in Pyrus bretschneider‘Dangshan Suli’

研究喷施Na2SeO3对砀山酥梨(Pyrus bretschneider Rehd.‘Dangshan Suli’)叶片衰老及抗氧化酶系统的影响。结果表明:与对照相比,喷施低浓度的硒(5mg·L-1),可明显延迟衰老叶片含水量、干样质量、叶绿素和可溶性蛋白含量的下降,显著提高SOD和GSH-Px活性,降低H2O2、和MDA含量,平均延迟落叶7.25d;喷施中等(10mg·L-1)和高浓度(20mg·L-1)的硒对延缓叶片衰老的效果变差,且浓度越高,效果越差;叶面喷硒对POD活性具有抑制作用。硒延缓梨树叶片衰老存在浓度差异,低浓度的硒可能通过提高SOD、GSH-Px等酶的活性参与叶片衰老进程的调控,从而降低膜脂过氧化水平,延长叶片功能期。

The effects of selenium（Se）on leaf senescence and antioxidase system in Pyrus bretschneider‘Dangshan Suli’were studied after fruit harvested. The results showed that：Spraying lower Se dosage（5 mg · L-1）delayed the decrease of water content,dry weight per unit area,chlorophyll and soluble protein content significantly,increased the activities of SOD and GSH-Px,decreased the content of H2O2, and MDA significantly in the senescing leaves,thereby deferred leaf senescence about 7.25 days;But the medium（10 mg · L-1）and higher Se dosage（20 mg · L-1）were not so effective in deferring leaf senescence,the higher the dosage,the lower the effect;However,Se inhibited POD activity. Therefore,the effect of Se on leaf senescence varied depending on its dosage,lower Se dosage may be involved in leaf-senescing regulation by enhancing the activities of SOD and GSH-Px,as a result decreases the membrane lipid peroxidation,postpones the functional period of the leaves.