Cu^2+、Zn^2+胁迫下苦草的生理生化特性研究

Study on physiological and biochemical characteristics of Vallisneria natans under Cu^2+and Zn^2+stress

以苦草为实验材料,分别采用Cu^2+、Zn^2+进行胁迫培养,从抗氧化酶活性(超氧化物歧化酶SOD、过氧化物酶POD和丙二醛MDA)和叶绿素含量(叶绿素a、叶绿素b、叶绿素a+b和叶绿素a/b)角度来了解苦草受重金属胁迫的生理生化响应。结果表明:T1处理组(Cu^2+=0.2mg/L、Zn^2+=2.0mg/L、Cu^2++Zn^2+=0.1+1.0mg/L)中,三种酶活性均低于CK组,而叶绿素a+b、叶绿素a和叶绿素b均较CK组大。T4处理范围内(Cu^2+<0.8mg/L、Zn^2+<8.0mg/L、Cu^2++Zn^2+<0.4+4.0mg/L),三种处理的抗氧化酶活性均呈上升趋势而当复合胁迫浓度达到最高时,酶活性出现降低的情况。叶绿素a、叶绿素b、叶绿素a+b和叶绿素a/b始终与重金属胁迫浓度呈正比关系。除SOD活性外,三种胁迫对苦草POD、MDA和各叶绿素含量的抑制效果表现为协同作用。

Vallisneria natans was selected as experimental material and stressed by Cu^2+and Zn^2+.The physiological and biochemical response ofV.natans was studied from the perspectives of antioxidant enzyme activities(superoxide dismutase,peroxidase and malondialdehyde)and chlorophyll content(chlorophyll a,chlorophyll b,chlorophyll a+b and chlorophyll a/b).The results showed that in the T1 group(Cu^2+=0.2mg/L,Zn^2+=2.0mg/L,and Cu^2++Zn^2+=0.1+1.0mg/L),the activities of the three enzymes were all lower than those of the CK group,while chlorophyll a+b,chlorophyll a and chlorophyll b were all higher than those of the CK group.Within the range of T4 treatment(Cu^2+<0.8mg/L,Zn^2+<8.0mg/L,and Cu^2++Zn^2+<0.4+4.0mg/L),the activity of antioxidant enzymes showed an upward trend.However.When the combined stress concentration reached the highest,the activity of antioxidant enzymes decreased.Chlorophyll a,chlorophyll b,chlorophyll a+b and chlorophyll a/b are always in direct proportion to the stress concentration of heavy metals.In addition to SOD activity,the three stresses showed synergistic effects on POD,MDA and chlorophyll contents.