镉胁迫下两株产铁载体/解磷菌株对黑麦草种子萌发及幼苗积累镉的影响

Effects of two siderophore producing/phosphorus solubilizing strains on seed germination and cadmium accumulation of Lolium perenne under cadmium stress

【目的】探讨两株产铁载体/解磷真菌对镉胁迫下黑麦草种子萌发及幼苗迁移积累镉的影响,以期为重金属污染土壤修复提供理论依据。【方法】以感染菌株ZR1、rL1和不感染菌株(CK)的黑麦草种子为材料,用不同质量浓度的镉溶液(0、1、5、10 mg·L^(-1))对黑麦草种子进行胁迫萌发试验,分析种子萌发、植株生长及植株体内镉含量的变化规律。【结果】随着胁迫质量浓度的升高,无论是发芽率、株高、根长、生物量均呈下降的趋势,根系、茎叶镉含量呈增加的趋势;当胁迫质量浓度为0~10 mg·L^(-1)时,在同一胁迫水平下,接种ZR1菌株的黑麦草发芽率与CK无显著差异(P>0.05),而rL1菌株处理的发芽率、干质量则比CK低;ZR1处理、rL1处理均对株高无显著性影响(P>0.05),但使根长分别提高了40.00%~125.34%、55.74%~143.62%,根系鲜质量分别增加了6.78%~59.26%、33.33%~238.98%,茎叶鲜质量分别增加了3.81%~114.29%、17.14%~169.72%,根系和茎叶镉含量分别提高了5.91%~28.52%和12.64%~22.66%、92.14%~202.78%和117.16%~226.07%,两者均能促进镉从根系转运至茎叶,使转运系数分别提高了7.69%~104.00%、9.52%~56.00%。【结论】接种ZR1、rL1菌株有效促进了黑麦草根系的生长,提高了黑麦草对重金属镉的积累,促进重金属镉从根部向地上部转运,表现出促进植物提取溶液镉的应用潜力。可见,菌株ZR1、rL1都具有一定的促生性,且能够活化镉,可与植物联合修复镉污染土壤。其中,在植物全发育期,建议施用ZR1菌株;在植物苗期,建议施用rL1菌株。

【Objective】In order to provide a theoretical foundation for heavy metal contaminated soil remediation,we investigated the effects of two siderophore producing and phosphorus solubilizing fungi strains on seed germination and cadmium migration in seedling of Lolium perenne L.under cadmium stress.【Method】A germination experiment was carried out on Lolium perenne L.seeds infected with strains ZR1 and rL1 under different concentrations of cadmium solution(0,1,5,10 mg·L^(-1)),and non-infected strains as CK treatments.The changes of seed germination,plant growth and cadmium contents in plants were analyzed.【Result】With the increase of stress concentration,the germination rate,plant height,roots length and biomass all showed a decreasing trend,while the cadmium contents in roots,stems and leaves showed an increasing trend.When the stress concentration was 0-10 mg·L^(-1),the germination rates of Lolium perenne treated with strains ZR1 showed no difference with those in the CK plants under the same stress level(P>0.05),but which were lower than those of CK treatments,as a result of additions with strains rL1.There was no significant difference on plant heights between strains ZR1 treatments and rL1 treatments(P>0.05).Compared with those of the CK,the roots length treated with strains ZR1 and rL1 increased by 40.00%-125.34% and 55.74%-143.62%,roots fresh weight increased by 6.78%-59.26% and 33.33%-238.98%,stems and leaves fresh weight increased by 3.81%-114.29% and 17.14%-169.72%,the cadmium contents increased by 5.91%-28.52% and 12.64%-22.66% in the roots,92.14%-202.78% and 117.16%-226.07% in the stems and leaves,respectively.Both of them can promoted the cadmium migration from roots to stems and leaves of Lolium perenne L.,and the transfer coefficient increased by 7.69%-104.00% and 9.52%-56.00%,respectively.【Conclusion】Strains ZR1 and rL1 can effectively promoted the roots growth of Lolium perenne L.,increased the cadmium accumulation in Lolium perenne L.,and promoted the cadmium transport from roots to aerial parts,showing the potential application of promoting plant extraction solution cadmium.It can be seen that strains ZR1 and rL1 can promoted plant growth and activate cadimium,which can be combined with plants to repaired cadmium-polluted soils.It was recommended that the strains ZR1 application be in the whole growth stage of plants and the strains rL1 application be in the seedling stage of plants.