Cd胁迫下绿豆和箭舌豌豆叶片抗氧化系统的变化

The Change of Antioxidant System in Leaves of Mung Bean(Phaseolus aureus) and Common Vetch(Vicia sativa) Seedlings Under Cd Stress

研究了Cd胁迫下绿豆(Phaseolus aureus)和箭舌豌豆(Vicia sativa)幼苗的生长,叶片内过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)、超氧化岐化酶(SOD)、愈创木酚过氧化物酶(GPOD)和谷胱甘肽还原酶(GR)的同工酶活性,还原性谷胱甘肽(GSH)和抗坏血酸(ASC)以及Cd含量的变化。结果显示,100μmol.L-1Cd胁迫9d期间,随着Cd胁迫时间的延长,绿豆和箭舌豌豆幼苗主根的伸长量和其根系干重显著降低(P<0.05),根表面出现越来越明显的褐色,绿豆叶表面出现可见的褐色斑点;两种植物叶片的CAT、APX和SOD同工酶活性以及绿豆叶片的GR活性呈先升后降的趋势,而两种植物叶的GPOD活性明显增加;在箭舌豌豆叶片中,GR活性随Cd暴露时间的延长而增加,而GSH先降后升;在绿豆叶片中,GSH和ASC随Cd暴露时间的延长而降低;与此同时,两种植物叶片中Cd的含量也随Cd胁迫时间的延长而增加,和箭舌豌豆相比,绿豆叶片中Cd含量增加更多。结果表明,箭舌豌豆有较强的抗氧化能力。

The effects of cadmium（Cd） on the plant growth,activities of antioxidant enzymes and contents of antioxidants in leaves of mung bean（Phaseolus aureus） and common vetch（Vicia sativa） were investigated using hydriponic experiments.Cadmium at 100 μmol·L-1 significantly decreased the main root elongation and roots dry weight,and increased activities of superoxide,dismutase（SOD）,catalase（CAT）,ascorbate peroxidase（APX） and guaiacol peroxidase（GPOD） in the leaves of both species.Activity of glutathione reductase（GR） in V.sativa leaves increased,and content of ascorbic acid（ASC） remained unchanged with Cd exposure time,whereas reduced glutathione（GSH） appeared to decrease for initial 6 days and then increased.But in P.aureus leaves,activity of GR and contents of GSH and ASC decreased with Cd exposure time.Compared to P.aureus,V.sativa had higher activities of SOD,CAT,APX and GR,and contents of ASC and GSH in the leaves under Cd stress.In contrast,V.sativa leaves had lower GPOD activity than P.aureus.Results from native PAGE showed that Cd treatment with 100 μmol·L-1 also changed the isozyme patterns of these antioxidant enzymes in the leaves of both species.The results suggested that tolerance of V.sativa to Cd could be attributed,at least in part,to its antioxidant capacity than P.aureus.