铅胁迫下金发草和狗牙根耐受性的对比  

Effect of lead stress on the growth and physiological characteristics of Pogonatherum paniceumand Cynodon dactylon

作　　者：于飞 马海天才 钟沃秀 陈舒雨 谢程程 李西[1] YU Fei;MAHAI Tiancai;ZHONG Woxiu;CHEN Shuyu;XIE Chengcheng;LI Xi(College of Landscape Architecture,Sichuan Agricultural University,Chengdu 611130,Sichuan,China;Chengdu Agricultural College,Chengdu 611130,Sichuan,China)

机构地区：[1]四川农业大学风景园林学院,四川成都611130 [2]成都农业科技职业学院,四川成都611130

出　　处：《草业科学》2018年第11期2602-2613,共12页Pratacultural Science

基　　金：四川省教育厅重点项目(17ZA0001);四川省科技厅应用基础项目(15JY0085)

摘　　要：通过盆栽试验,设置不同浓度梯度Pb^(2+)(0、250、500、1 000、2 000、4 000mg·kg^(-1))污染土壤,研究Pb胁迫下金发草(Pogonatherum paniceum)和狗牙根(Cynodon dactylon)的生长及生理指标,分析比较两种园林中常见草种对Pb的耐受能力,为城市生态修复筛选出优良耐Pb胁迫的草本植物提供一定的理论依据。结果表明,随着Pb胁迫浓度的增大,金发草和狗牙根的生长受到抑制,叶片外观质量、生物量、净光合速率(Pn)及叶绿素含量均下降,与同期对照相比均差异显著(P<0.05);两种草的相对电导率(REC)显著升高(P<0.05),且均能够通过增加渗透调节物质和提高抗氧化酶活性来抵御土壤Pb胁迫;两种草的丙二醛(MDA)、可溶性糖、可溶性蛋白含量和超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性以及狗牙根过氧化物酶(POD)活性均先升高后下降,金发草POD活性持续升高;Pb浓度4 000mg·kg^(-1)时金发草达到了自身Pb耐受阀值,表现出明显的Pb毒害特征,狗牙根则未达到自身阀值;Pb浓度2 000mg·kg^(-1)时两种草均能保持较为正常的生长状态;金发草和狗牙根对Pb均具有较高的吸收富集能力,但未达到超富集植物标准。综合分析两种草对Pb胁迫响应变化的差异,在Pb耐受性方面狗牙根强于金发草,因此狗牙根能够更好地适应土壤Pb污染环境,在Pb污染土壤修复中具有更大的应用价值。A pot experiment was conducted to study the growth and physiological indices of Pogonatherum paniceum and Cynodon dactylon under Pb stress by contaminating soils with different concentrations of Pb 2+(0,250,500,1 000,2 000,and 4 000 mg·kg-1).We analyzed and compared the tolerance of these two common herbs to Pb in gardens,identified herbs with excellent Pb resistance for urban ecological restoration,and provide related theoretical bases.The results showed that with increasing Pb stress,P.paniceum and C.dactylon both showed stunted growth.The appearance quality,biomass,net photosynthetic rate(P n),and chlorophyll contents of leaves decreased,and exhibited significant differences compared with plants that were not exposed to Pb(P<0.05).Exposure to Pb significantly increased the relative electrical conductivity(REC)values(P<0.05)by promoting increases in the content of osmotic adjustment substances and modifying antioxidant enzyme activities.For both plant species,the malondialdehyde(MDA),soluble sugar,and soluble protein contents,and superoxide dismutase(SOD),catalase(CAT),and peroxidase(POD)enzyme activities all showed an initial increase in response to Pb treatment followed by a gradual decrease;the exception being the POD activity of P.paniceum,which showed a steady increase.At a Pb 2+concentration of 4 000 mg·kg-1,P.paniceum reached its Pb tolerance threshold,showing obvious Pb toxicity characteristics,whereas C.dactylon did not reach a tolerance threshold at this concentration.When exposed to 2 000 mg·kg-1 Pb 2+,both P.paniceum and C.dactylon can maintain a normal growth state.These plants have a high ability to absorb and enrich lead in soil,although they do not show efficiencies comparable to those of hyperaccumulator plants.Comprehensive analyses of the different responses under Pb stress indicated that C.dactylon shows a considerably greater resistance to lead stress than P.paniceum.Our study thus provides evidence that C.dactylon has substantial potential for use in the phytoremediation of Pb-contamina

关 键 词：PB胁迫 金发草 狗牙根 耐受能力 生态修复 阀值 响应 

分 类 号：S543.903.4[农业科学—作物学] Q945.78[生物学—植物学]