铅、镉、铜对4种入侵植物种子萌发及幼苗生长的影响

Influence of lead,cadmium and copper stress on seed germination and seedling growth of four invasive plants

采用纸皿法以去离子水为对照,研究了不同质量浓度Pb^(2+)、Cd^(2+)和Cu^(2+)胁迫对4种入侵植物假酸浆(Nicandra physaloides)、屋根草(Crepis tectorum)、繁穗苋(Amaranthus paniculatus)和长毛月见草(Oenothera villosa)种子萌发及幼苗生长的影响,以为入侵植物在重金属污染土壤治理与修复中的利用提供新思路.结果表明:随着Pb^(2+)、Cd^(2+)和Cu^(2+)质量浓度的增大,4种入侵植物种子的发芽率、发芽指数、初生根长度、胚芽长度及幼苗的生物量呈下降趋势.其中,假酸浆种子的发芽率、发芽指数对Pb^(2+)、Cd^(2+)、Cu^(2+)胁迫不敏感(P>0.05);不同重金属胁迫对4种入侵植物幼苗生长指标的抑制作用明显强于种子萌发特性.采用模糊数学隶属函数法对4种入侵植物进行了耐重金属胁迫评价,耐Pb^(2+)的强弱顺序为:假酸浆>屋根草>长毛月见草>繁穗苋;耐Cd^(2+)的强弱顺序为:假酸浆>屋根草>长毛月见草>繁穗苋;耐Cu^(2+)的强弱顺序为:假酸浆>屋根草>长毛月见草>繁穗苋.综合分析假酸浆种子对重金属Pb^(2+),Cd^(2+)和Cu^(2+)的耐性较强,在土壤重金属污染治理中具有较大的应用潜力.

With the deionized water as control test to seed of Oenothera villosa, Nicandra physaloides, Crepis tectorum and Amaranthus paniculatus as materials, this work studied the heavy metal lead （Pb）, cadmium （Cd）, and copper （Cu） single stress on seed germination and seedling growth influence,in order to provide scientific basis for screening hyper-accumulation plants. The results show that the seed germination rate, germination index, root length and shoot length and biomass of the four invasive plants decreased with the increasing of Pb^2＋, Cd^2＋and Cu^2＋ concentrations, and N. physaloides of the seed germination rate and germination index are not sensitive （P〉0.05）. Different heavy metal stress on four invasive plants of seed germination are stronger than seedling growth. The comprehensive evaluations of the resistance of invasive plants to the metal ions during germination stage were done by membership function method. The resistance of seed to Pb^2＋ stress was ordered as N. physaloides〉C, tectorurn〉O, villosa〉A, paniculatus. The resistance of seed to Cd^2＋ stress was ordered as N. physaloides〉C, tectorurn〉O, villosa〉A, paniculatus. The resistance of seed to Cu^2＋ stress was ordered as N. physaloides〉C, tectorurn〉O, villosa〉A, paniculatus. The comprehensive analyses shows that the resistances of the N. physaloides seed to heavy metals of Pbz＋ ,Cd^2＋ and Cu^2＋ during seed germination period were better than other three tested plants.