5种豆科植物对铅、锌及其复合作用的耐性研究

为了给兰坪铅锌尾矿区植被恢复重建以及矿区周边污染农田等修复、生境的改善提供必要的参考依据，研究了不同质量浓度的铅、锌重金属离子单一作用和复合作用胁迫下对5种豆科植物种子萌发和幼苗生长的影响。通过水培实验和无土栽培实验，进行了植物对重金属铅、锌的耐性研究。结果表明：（1）在单一铅、锌作用下，除双荚决明外，重金属对植物种子的发芽力具有低促高抑的作用。紫花苜蓿和三叶草有较强的耐受Pb2+胁迫能力。当铅、锌交互作用时，在铅含量较低时仍具有促进种子发芽的作用；但当铅含量达到一定浓度时，铅对植物的毒害作用骤然增强。（2）幼苗生长受重金属影响：在锌胁迫下，5种豆科植物间无显著差异；而在铅胁迫下，当Pb2+含量增加到1100 mg/L时，紫花苜蓿的表现优于其他4种植物。（3）有265 mg/L Zn2+参与下，Pb2+、Zn2+复合胁迫对植物幼苗生长的影响基本是抑制作用，且随着Pb2+浓度的增加其抑制作用越显著。铅锌交互作用时，一定浓度的锌增加了重金属铅对植物体的毒害作用。

Study on Tolerance of Five Legumes to Pb2+, Zn2+ and Their Combined Pollution

In order to provide reference basis for the vegetation restoration and reconstruction of Pb-Zn mining tailings and peripheral polluted farmland,as well as habitat improvement in Lanping County,the impact of the single and combined of Pb～（2＋） and Zn～（2＋） ions with different contents on the germination and seedling growth of five leguminous plants was studied in this paper.The experiment researched the tolerance of the five legumes species to Pb～（2＋） ,Zn～（2＋） and their combined pollution by solution culture and soilless culture.The results showed that：（1） Except for Cassia bicapsularis,the seed germination increased under the treatments with single lead and zinc at low concentration,but it could reduce when lead and zinc reached high concentration.Both Medicago sativa and Trifolium repens had much tolerance to lead than the other three.Treated with combined lead and zinc ions,the germination of seeds could be promoted by zinc ion at low level of lead concentration,but it was inhibited by both lead and zinc when lead reached high level concentration.（2） The impact of heavy metals on the seedling growth was as follows：being treated with single zinc ion,there was no significant differences of growth between the five legumes species.While being treated with single lead ion,the seedlings growth of Medicago sativa was better than the other four once Pb 2＋ concentration being up to 1100 mg/L.（3） When the concentration of Zn 2＋ was 265 mg/L,the growth of seedlings was inhibited obviously,and the inhibition increased with Pb～（2＋） concentration increase and Pb～（2＋） concentration was main inhibition factor.It suggested a certain concentration of zinc enhanced the poison effect of lead to leguminous seeds when treated with combined lead and zinc ions.