铅胁迫对小叶黄杨幼苗生理生化指标的影响

摘要

Effects of lead stress on physiological and biochemical characteristics were studied through a pot experiment to provide a reference for Pb contamination management in soil.Results:Pb stress resulted in biomass reduction of roots,stems,leaves and the whole plant,when soil Pb concentration was above 1 000 mg/kg,the biomass significantly decreased.The activity of SOD,POD,CAT and MDA content increased with Pb concentration increasing,SOD and CAT reached the peak value when Pb concentration was over 2 000 mg/kg,and POD reached the peak value when Pb concentration was over 3000 mg/kg, soluble sugar content reached the maximum when Pb concentration was over 1000 mg/kg;Chlorophyll content decreased with soil Pb concentration increasing.The roots of B.harlandi seeding was the main absorption part of Pb,Pb absorption amount was the lowest in leaves.There were significant correlations between seedling biomass and physiological indexes when Pb concentration was below 1000 mg/kg,which was weakened when Pb concentration was over 1000 mg/kg.Conclusion:the B.harlandi seedlings could grow and survive naturally when Pb concentration was below 1000 mg/kg,while self-regulation resistance was reduced and physiological responses and growth were inhibited when above 1000 mg/kg.%为利用小叶黄杨治理Pb污染土壤提供参考，利用盆栽方法研究重金属铅（Pb）胁迫对小叶黄杨幼苗生理生化的影响。结果表明：Pb胁迫可导致小叶黄杨幼苗根、茎、叶以及整株生物量的减少，当土壤Pb浓度＞1000 mg/kg时其生物量下降显著。SOD、POD、CAT、MDA含量随土壤 Pb浓度的升高而升高，其中SOD、CAT在土壤Pb浓度为2000 mg/kg时达到峰值，POD在土壤Pb浓度为3000 mg/kg时达到峰值，MDA在土壤Pb浓度为1000 mg/kg时达到峰值。可溶性糖含量在 Pb浓度为1000 mg/kg时达到最大值。叶绿素含量随土壤Pb浓度的升高而降低。小叶黄杨幼苗根系是 Pb的主要吸收部位，叶片对 Pb的吸收量最低。在土壤Pb浓度＜1000 mg/kg时，小叶黄杨幼苗生物量与幼苗生理指标存在显著相关性，但土壤Pb浓度＞1000 mg/kg时，相关性减弱。结论：在土壤Pb浓度1000 mg/kg以下小叶黄杨幼苗可以正常生长生存，土壤Pb浓度高于1000 mg/kg时，小叶黄杨幼苗自身调节抵抗能力降低，生理反应和生长均受到抑制。