【摘要】 【目的】比较两品种苣苋草对Cd、Pb胁迫的生理生化响应的差异性，寻找对Cd、Pb胁迫抗性较强的品种。【方法】采用盆栽试验，研究不同浓度Cd、Pb单一及复合胁迫下‘R104’和‘K472’两品种苣苋草的生物量，Cd、Pb积累特性，渗透调节物质含量和抗氧化酶活性的变化。【结果】两品种苣苋草的生物量在单一Cd胁迫时下降，在低浓度Pb(2.5 g·kg^-1)胁迫时上升，在高浓度Pb(10.0 g·kg^-1)胁迫时下降，在Cd、Pb复合胁迫时表现为先上升后下降的趋势。Cd、Pb单一胁迫下，苣苋草的Cd、Pb含量随着相应元素胁迫浓度的增大而上升；Cd、Pb复合胁迫下，苣苋草的Cd、Pb含量随着另一元素胁迫浓度的增大呈先上升后下降的趋势。随着Cd、Pb单一及复合胁迫浓度的增大，苣苋草超氧化物歧化酶（SOD）活性呈先上升后下降的趋势，过氧化物酶（POD）活性逐渐上升，过氧化氢酶（CAT）活性呈抑制效应。Cd、Pb交互作用在苣苋草生物量和SOD活性上总体表现为复合胁迫>单一胁迫；在植物重金属含量上表现为：低浓度Cd与Pb互为促进作用，高浓度Cd与Pb互为拮抗作用。【结论】苣苋草主要通过提高POD活性和维持CAT活性来抵抗Cd、Pb胁迫；‘R104’的抗性大于‘K472’,表明‘R104’更适合在重金属Pb污染的土壤区域推广种植。更多还原

【Abstract】 【Objective】Two varieties of Amaranthus hypochondriacus were compared on the physiological and biochemical responses to cadmium（Cd） and lead（Pb） stresses to screen variety showing resistant to Cd and Pb stresses. 【Method】The biomass, Cd and Pb accumulation characteristics, osmoregulatory substance content and antioxidant enzyme activities of 2 A.hypochondriacus varieties（’R104’ and ’K472’） were investigated under single or compound stress of Cd and Pb with different concentrations by pot experiment. 【Result】The biomass of the 2 varieties decreased under single Cd stress and higher Pb stress(10.0 g·kg^-1), increased under lower Pb stress(2.5 g·kg^-1), and firstly rose and then declined under compound stress of Cd and Pb. Under single stress, the Cd or Pb content in A.hypochondriacus increased with the concentration of corresponding elements applied; while under compound stress, the Cd（or Pb） content in A.hypochondriacus increased and then decreased with the concentration of Pb（or Cd）. With the increase of single or compound stress of Cd and Pb, superoxide dismutase（SOD） activity firstly increased and then decreased, peroxidase（POD） activity gradually increased, and catalase（CAT） activity was inhibited. The effect of compound stress of Cd and Pb on the biomass and SOD activity was generally greater than that of single stress of Cd or Pb. Either lower Cd or Pb stress promoted the accumulation of the other, while higher Cd or Pb stress was antagonistic to the accumulation of the counterpart. 【Conclusion】The increased resistance to Cd and Pb stress in A.hypochondriacus was mainly contributed to enhanced POD activity and maintained CAT activity; considering the higher resistance of ’R104’ comparing to ’K472’, ’R104’ was more suitable for cultivation promotion on Pb contaminated region.更多还原