外源褪黑素对铅胁迫下狗牙根生长及抗氧化性的影响

Effects of Exogenous Melatonin on the Growth and Antioxidant of Bermudagrass under Lead Stress

以新农1号狗牙根和天堂328狗牙根为材料,在狗牙根种茎生长20 d后,以浓度0、5、20、50μmol/L褪黑素对狗牙根进行浇灌处理,之后以浓度0、1000、2000 mg/kg醋酸铅溶液对狗牙根进行胁迫处理。结果表明:未施用醋酸铅时,新农1号狗牙根的相对含水量、可溶性蛋白含量、抗氧化酶活性均显著高于天堂328狗牙根(P<0.05)。铅胁迫导致狗牙根生长受阻,同时细胞的氧化应激反应增加。在铅胁迫下,与对照相比,用20μmol/L和50μmol/L浓度的褪黑素预处理后的狗牙根表现出更高的抗氧化酶活性和非酶抗氧化物质含量,叶绿素含量和相对含水量增加。可见,褪黑素通过增强狗牙根的抗氧化酶活性,增加非酶抗氧化物质含量来清除铅胁迫下产生的自由基。

The aim of the study was to investigate the effects of exogenous melatonin on the growth characteristics and antioxidant of bermudagrass(Cynodon dactylon L.)under lead stress.C.dactylon cv.Xinnong No.1 and C.dactylon×C.trasvalensis cv.Tifgreen were used as materials.After 20 days growth of bermudagrass stems,they were treated with 0,5,20 and 50μmol/L melatonin,and then treated with lead acetate solution at the concentrations of 0,1000 and 2000 mg/kg.The results showed that before lead stress,the relative water content,soluble protein,and antioxidant enzymes contents of Cynodon dactylon cv.Xinnong No.1 were significantly higher than those of C.dactylon×C.trasvalensis cv.Tifgreen(P<0.05).Lead stresses inhibits the growth of bermudagrass and increased cellular oxidative stress response.Under lead stress,compared with the control,the bermudagrass pretreated with 20μmol/L or 50μmol/L concentrations of melatonin showed higher antioxidant enzymes activity and non-enzymatic antioxidants substance content,and increased chlorophyll and relative water content.It can be seen that melatonin enhanced the antioxidant enzyme activity of bermudagrass and enhanced the antioxidant defense system to eliminate free radicals produced under lead stress,which can provide theoretical support and practical basis for the application of exogenous melatonin to improve the remediation of lead contaminated soil by bermudagrass.