刺儿菜镉富集特征及其根际细菌群落对镉胁迫的响应

Cd Accumulation Characteristics of Cirsium arvense var. Integrifolium and Response of Rhizosphere Bacterial Communities to Cd Stress

[目的]探明刺儿菜在重金属Cd胁迫下的生长、Cd积累特性以及根际细菌群落变化规律。[方法]通过温室盆栽试验,对比不同Cd含量(0、4和16 mg/kg)土壤中刺儿菜的生长和Cd积累特征差异,利用16S rDNA基因高通量测序技术,探究刺儿菜根际细菌群落结构在不同土壤Cd梯度下的变化规律。[结果]刺儿菜地上部和根部对Cd胁迫的响应明显不同。株高、基径和叶片数均随土壤Cd含量增加而降低,根长随土壤Cd含量增加而先增加后减少。Cd胁迫对刺儿菜生物量呈现出“低促高抑”的作用,在4 mg/kg土壤中生长的刺儿菜生物量比对照组(0 mg/kg)高52.68%。刺儿菜具有优良的Cd积累和转运能力,其富集系数大于5,转移系数大于4。Cd胁迫对刺儿菜根际细菌群落组成有明显影响,不同Cd含量土壤中刺儿菜根际菌优势菌门的相对丰度存在明显差异。[结论]刺儿菜能够在含Cd土壤(低于16 mg/kg)中生长,且富集能力强,是一种潜在的Cd污染植物修复资源,其根际细菌群落组成也会对Cd胁迫作出响应。

[Objective]To investigate the growth and accumulation characteristics of C.arvense under heavy metal Cd stress and the impact on the rhizosphere bacterial community.[Method]Through greenhouse potting experiments,we compared the differences in growth and Cd accumulation characteristics of C.arvense in soils with different Cd contents(0,4 and 16 mg/kg).We utilized high-throughput sequencing of 16S rDNA genes to determine the changing rules of the rhizosphere bacterial community structure of C.arvense under different soil Cd gradients.[Result]The responses of C.arvense to Cd stress in the aerial part and root part were significantly different:plant height,basal diameter and the number of leaves all decreased with increasing soil Cd gradients,but root length increased first and then decreased with increasing soil Cd gradients.Cd stress showed a“low-promoting and high-suppressing”effect on the biomass of C.arvense.The biomass of C.arvense grown in 4 mg/kg soil was 52.68%higher than that of the control group(0 mg/kg).C.arvense had excellent Cd accumulation and transport capacity,with a bioaccumulation factor greater than five and a translocation factor greater than four.Cd stress had an effect on the rhizosphere bacterial community composition,and there is a significant difference in the relative abundance of dominant phyla in soil with different Cd gradients.[Conclusion]C.arvense can grow in Cd-containing soil(less than 16 mg/kg)and has an excellent accumulation ability,making it a potential Cd contaminated phytoremediation resource,and its rhizosphere bacterial community composition also responds to Cd stress.