铅胁迫对金丝草生长及生理生化的影响

采用土培方法,探究不同梯度铅胁迫(0、1000、2000和3000 mg·kg^-1)对金丝草生长形态、体内抗氧化系统和渗透调节物质的影响。结果表明:低浓度(1000 mg·kg^-1)处理会诱导金丝草叶片过氧化物酶(POD)活性、可溶性蛋白(SP)含量和根系抗超氧阴离子自由基活力(ASAFR)、可溶性糖(SS)及脯氨酸(Pro)含量增加,使得金丝草植株总抗氧化能力(T-AOC)处于较高水平,促进了金丝草株高、叶长和生物量的增加。随胁迫浓度增加,高浓度(2000~3000 mg·kg^-1)处理下,金丝草叶片和根系丙二醛(MDA)含量迅速增加,株高、叶长、叶面积和生物量下降,生长受到抑制。但金丝草通过增强叶片和根系POD、过氧化氢酶(CAT)活性来抵御过氧化作用,提高可溶性蛋白和可溶性糖含量维持细胞正常运作,增加根系生物量占比来加强根系发育,一定程度适应了高浓度铅胁迫。综上表明,金丝草主要通过叶片和根系不同抗氧化酶差异化响应、提高渗透调节物质含量,提升金丝草植株总抗氧化能力等途径来提高Pb耐性,对Pb污染矿区植物修复有较大潜力。

Effects of lead stress on growth and physiology of Pogonatherum crinitum

In order to understand the response mechanisms of Pogonatherum crinitum growing in contaminated mining areas,a pot culture experiment was carried out to study the physiological indexes of P.crinitum under varying Pb stress concentrations.Low Pb concentration (1000 mg · kg-1) had promotional effects on POD activity,soluble protein content in leaves and ASAFR activity,and on soluble sugar content and proline content in roots,allowing P.crinitum plants to maintain their overall antioxidant capacity at a high level and promoting plant height,leaf length and biomass.Increasing Pb concentrations (2000,3000 mg · kg-1) inhibited shoot height,leaf length,leaf area and biomass,but increased the MDA content of plants.P.crinitum's adaptability to high Pb concentration treatments was evident as increasing POD and CAT activities in leaves and roots to enhance antioxidant activity,as increasing soluble protein and soluble sugar content to maintain the normal operation of cells,and as the promotion of root development and root ∶ shoot to keep T-AOC at a high level.These findings indicate that P.crinitum can adapt to Pb stress by adjusting its antioxidant system and enhancing its osmotic adjustment substance contents,suggesting that the plant has application potential for the remediation of Pb polluted soil.