不同品种(系)牧草镉修复能力综合评价

Comprehensive Evaluation of the Cadmium Remediation Capacity of Different Species(strains)of Forage Grasses

该研究选用3种高丹草、2种苏丹草、2种杂交狼尾草、一年生黑麦草和多年生黑麦草共9个牧草品系,采用盆栽试验,设置0(CK)、10(Cd10)、20 mg/kg(Cd20)镉胁迫处理,考察不同品系的生长指标、镉含量和富集指标,运用极差化法和主成分分析建立综合评价模型,通过计算各牧草在模型中的综合得分,筛选出最适宜实地修复的牧草,探究不同品种和不同品系牧草的镉修复能力差异,建立Cd污染土壤植物修复能力评价体系,发掘兼顾富集量和后处理的镉污染土壤植物修复资源。结果表明:(1)镉胁迫会不同程度降低牧草的株高和生物量,其中江苏苏丹草在Cd10和Cd20中的耐胁迫能力均较强;(2)在Cd10和Cd20处理下,一年生和多年生黑麦草均具有较高的地上部和地下部Cd含量,高丹草的3个品系在Cd含量和Cd积累量两方面存在较大差异;(3)在Cd10和Cd20处理下,高丹草和黑麦草的富集指标表现优异,且富集指标在高丹草品系间存在较大差异;(4)2个镉质量分数处理下综合评价得分最高的均是一年生黑麦草,其次为高丹草。研究表明,参试牧草对镉胁迫均有较强的耐受性,但耐受能力和富集能力在品系间存在明显差异,并以高丹草品系间差异最大;一年生黑麦草能耐受20 mg/kg以下镉胁迫,且生物量较小,对镉有较强的浓缩效应,可作为镉污染土壤实地修复的可靠材料;综合评价模型可作为镉污染修复植物资源筛选的可靠方法。

In this study,nine strains of forage grasses,including three Sorghum bicolor×Sorghum sudanense(SS BJ,SS JS,SS HF),two S.sudanense(Piper)Stapf.(SU JS,SU HF),two Pennisetum americanum×P.purpureum(PP JS,PP HF),Lolium multiflorum Lam.(LM JS)and Lolium perenne L.(LP JS),were used as research material in pot experiment with 0(CK),10(Cd10)and 20 mg/kg(Cd20)Cd stress treatments.The growth index,Cd content and enrichment index of different strains were measured.We investigated the Cd remediation capacity of different species and strains of forage grasses to establish an evaluation system for the phytoremediation capacity of Cd-contaminated soil,and to discover phytoremediation resources for Cd-contaminated soil that take into account enrichment and post-treatment.The results showed that:(1)Both of the plant height and biomass of all forage grasses at different degrees under Cd stress,among which SU JS had a high tolerant to Cd stress under both Cd10 and Cd20 treatments.(2)Both LM JS and LP JS had higher above-ground and below-ground Cd contents under Cd10 and Cd20 treatments,and the three strains of S.bicolor×S.sudanense had greater differences both in Cd content and Cd accumulation.There were greater differences in Cd content and Cd accumulation among the three strains of S.bicolor×S.sudanense.(3)Under the treatments of Cd10 and Cd20,the enrichment indexes of S.bicolor×S.sudanense and L.multiflorum Lam.performed well,and the enrichment indexes were different greatly among the S.bicolor×S.sudanense strains.(4)L.multiflorum Lam.could obtain the highest overall evaluation scores at two Cd treatments,and the next was S.bicolor×S.sudanense.This study showed that all of the tested forage grasses had a strong tolerance to Cd stress,but there were significant differences in tolerance and enrichment ability among the different strains,with the greatest difference among the S.bicolor×S.sudanense strains.The model developed in this study could be used as a reliable method for the selection of plant resources for the remediation of Cd contamination.