Pb、Ni胁迫对大羽藓抗氧化酶系统的影响

Effects of Pb and Ni stress on antioxidant enzyme system of Thuidium cymbifolium

研究了Pb、Ni单一及复合胁迫下大羽藓细胞活性氧自由基的累积与清除、光合系统和膜系统的受损情况及其抗氧化酶系统的变化.结果表明:在较低胁迫浓度(Pb<0.1mmol.L-1,Ni<0.01mmol·L-1)下,大羽藓叶绿素含量具有应激效应,在较高胁迫浓度(Pb>0.1mmol·L-1,Ni>0.01mmol·L-1)下则具有抑制效应;随Pb-Ni复合胁迫浓度的增加,苔藓活性氧自由基和丙二醛的累积量逐渐增大;大羽藓超氧化物歧化酶和过氧化氢酶活性降低,过氧化物酶活性增加,过氧化物酶在清除Pb、Ni胁迫产生的活性氧自由基的过程中起着重要作用.大羽藓丙二醛含量和过氧化氢酶活性对Pb、Ni胁迫具有浓度依赖性,可以将其作为监测该类重金属污染的生物标志物.

This paper studied the accumulation and scavenging of active oxygen radicals, injury of photosynthetic system and membrane system, and changes of antioxidant enzyme system in Thuidium cymbifolium cells under single and combined stress of Pb and Ni. Under low concentration of Pb and Ni （Pb 〈0. 1 mmol· L^- 1 ,Ni 〈0. 01mmol· L^- 1）, the chlorophyll content of T. cymbifolium increased ; while under high concentration of Pb and Ni （Pb 〉 0. 1 mmol· L^- 1, Ni 〉 0. 01 mmol· L^- 1）, it was in adverse. There was a dose-dependent accumulation of reactive oxide species （ROS） and malondialdehyde （MDA） under combined Pb and Ni stress. The superoxide dismutase （SOD） and catalase （CAT） activities decreased while the peroxidase （POD） activity increased with increasing Pb and Ni concentration, indicating the important role of POD in eliminating ROS under Pb and Ni stress. The dose-dependent change of MDA content and CAT activity under Pb and Ni stress suggested that T. cymbifolium could be used as a biomarker in pollution monitoring of these two heavy metals.