低剂量微波辐射对增强UV-B辐射损伤菘蓝幼苗抗氧化酶活性的影响

为了探讨低剂量微波对增强UV-B辐射损伤菘蓝(Isatis indigotica Fort.)的修复作用,将经过10.08 kJ·m-2·d-1辐射损伤(PAR=220 μmol·m-2·s-1)的菘蓝幼苗分别经0、3、6、9和12 s等不同时间的微波辐照(126 mW·cm-2,2 450 MHz),然后测定其幼苗MDA含量、紫外吸收物质含量、抗坏血酸含量以及3种抗氧化酶SOD、CAT和POD活性.结果表明,增强UV-B辐射损伤菘蓝在微波的作用下其菘蓝幼苗中SOD、CAT和POD活性及紫外吸收物质含量、抗坏血酸含量提高,MDA含量得到显著的降低,说明微波对增强UV-B辐射伤害菘蓝幼苗具有修复作用.但是,随着微波剂量的增加,这种修复效应减弱,甚至消失.上述参数的变化说明适量时间的微波处理可以提高菘蓝对增强UV-B辐射的抵抗能力,并在此基础上初步探讨了微波的修复机理.

Influence of Low Doses Microwave Radiation on Activities of Antioxidative Enzymes of Isatis indigotica Seedlings Exposed to Enhanced UV-B Radiation

In order to determine the damage repair role of microwave in the stress resistance of Isatis indigotica to UV-B radiation,the seedlings subjected to UV-B radiation of 10.08 kJ·m-2·d-1 for 8 h under photosynthetically active radiation (220 μmol·m-2·s-1) were exposed to microwave radiation of 0,3,6,9 and 12 s (126 mW·cm-2,2 450 MHz).Afterwards,changes of UV-B-injured leaves of the fourth in the activities of enzymes,such as SOD,CAT and POD,and in the concentration of malondialdehyde (MDA) and ascorbic acid (AsA),and UV absorbing compounds were measured to test the effects of microwave treatment.The results indicated when the seedlings were treated using 10.08 kJ·m-2·d-1 UV-B and then exposed to shorter microwave radiation,the activities of SOD,CAT and POD,and the concentration of AsA,and UV absorbing compounds increased significantly.UV-B-injured Isatis indigotica seedlings treated with microwave radiation recovered faster from enhanced UV-B stress resistance because the MDA concentration decreased compared with UV-B treatment alone.However,the repaired effect on seedlings injured by UV-B damage became weak,and even lost with the augment of microwave radiation time.Those changes in the vigor of enzymes and in concentration of MDA,AsA and UV-B absorbing compound suggested that microwave radiation of suitable time length had a positive physiological repair role on UV-B-damaged plants.However,the mechanisms of microwave repair effect in plants damaged by UV-B are not clear at present and additional work will be needed to investigate in the future.