铅、锌、镉胁迫对多年生黑麦草生长及生理生化特性的影响

Effects of Pb,Zn and Cd on Growth,Physiological and Biochemical Characteristics of Perennial Ryegrass

为了解多年生黑麦草对Pb、Zn、Cd的耐性和土壤重金属污染的修复潜力,采用砂培法研究铅(Pb)、锌(Zn)、镉(Cd)对多年生黑麦草生长发育及生理生化特性的影响。Pb^(2+)设0(CK)、500(Pb500)、1000(Pb1000)、2000 mg·kg-1(Pb2000)四个处理,Zn^(2+)设0(CK)、500(Zn500)、1000(Zn1000)、2000 mg·kg-1(Zn2000)四个处理,Cd^(2+)设0(CK)、10(Cd10)、20(Cd20)、50 mg·kg-1(Cd50)四个处理,测定不同浓度Pb^(2+)、Zn^(2+)、Cd^(2+)胁迫下多年生黑麦草的形态特征、叶绿素含量、抗氧化酶活性、膜脂过氧化产物含量、渗透调节物质含量,利用Fuzzy隶属函数法对这些指标进行综合评价。结果表明:(1)Pb^(2+)、Zn^(2+)、Cd^(2+)胁迫显著抑制多年生黑麦草的生长,Pb2000、Zn2000和Cd50三个处理对黑麦草的生物量、分蘖及根系生长的抑制作用最显著。(2)Pb^(2+)、Zn^(2+)和Cd^(2+)胁迫时,多年生黑麦草会通过增加植物的渗透调节物质和抗氧化酶活性减缓对植物的伤害。超氧化物歧化酶、过氧化物酶活性均随着Pb^(2+)、Zn^(2+)和Cd^(2+)胁迫浓度的增加呈现先增加后减少趋势;丙二醛和脯氨酸含量随着重金属浓度增加而增加;Pb500和Cd10处理的可溶性糖含量下降,而Zn500处理的可溶性糖含量增加。(3)多年生黑麦草对Pb^(2+)、Zn^(2+)和Cd^(2+)胁迫有一定的耐受性,不同处理的植株抗逆性由强到弱依次表现为:Zn500>CK>Zn1000>Cd10>Pb500>Zn2000>Cd20>Pb1000>Pb2000>Cd50。研究结果为生态恢复提供理论支撑和数据支持。

In order to understand the tolerance of perennial ryegrass to Pb,Zn and Cd and the remediation potential of heavy metal pollution in soil,sand culture method was used to study the effects of plumbum(Pb),zinc(Zn)and cadmium(Cd)on the growth,physiological and biochemical characteristics of perennial ryegrass.Pb^(2+)treatments with 0(CK),500(Pb500),1000(Pb1000)and 2000 mg·kg-1(Pb2000)concentrations,Zn^(2+)treatments with 0(CK),500(Zn500),1000(Zn1000)and 2000 mg·kg-1(Zn2000)concentrations,Cd^(2+)treatments with 0(CK),10(Cd10),20(Cd20)and 50 mg·kg-1(Cd50)concentrations were set up.The morphological characteristics,chlorophyll content,antioxidant enzymes activities,membrane lipid peroxidation product content and osmotic adjustment substances contents of perennial ryegrass under different concentrations of Pb^(2+),Zn^(2+)and Cd^(2+)were determined,and these indexes were comprehensively evaluated by Fuzzy membership function method.The results showed that:(1)Pb^(2+),Zn^(2+)and Cd^(2+)stress significantly inhibited the growth of perennial ryegrass,and Pb2000,Zn2000 and Cd50 treatments had the most significant inhibition on biomass,tiller number and root growth of perennial ryegrass.(2)Under the stress of Pb^(2+),Zn^(2+)and Cd^(2+),perennial ryegrass slowed down the damage to plants by increasing osmotic adjustment substances and antioxidant enzymes activities of plants.The contents of superoxide dismutase and peroxidase were increased first and then decreased with the increase of Pb^(2+),Zn^(2+)and Cd^(2+)concentrations.Malondialdehyde and proline contents were increased with the increase of Pb^(2+),Zn^(2+)and Cd^(2+)concentrations.With the increase of Pb^(2+),Zn^(2+)and Cd^(2+)concentrations,the soluble sugar contents of Pb500 and Cd10 treatments were decreased,while that of Zn500 treatment were increased.(3)Perennial ryegrass had certain tolerance to Pb^(2+),Zn^(2+)and Cd^(2+),and the stress resistance of plants in all treatments showed as following:Zn500>CK>Zn1000>Cd10>Pb 500>Zn2000>Cd20>Pb1000>Pb2000>Cd50.The present research provided theoretical and data support for ecological restoration.