水苏糖在重金属污染土壤中的根际微生态效应研究

Rhizosphere microecological effects of stachyose amendment in heavy metal contaminated soils

  • 摘要: 为进一步探究植物根系分泌物如何主动重塑根际微生物群落以增强其自身逆境耐受性,该研究探究了镉胁迫下的差异根际分泌物水苏糖的根际微生态效应及富集益生菌的作用机制. 结果显示,属水平上,水苏糖处理显著富集了Massilia属的细菌,其代表菌株Massilia oculi CCUG 43427A(BC18)被成功分离得到. 盆栽实验结果表明,BC18能显著降低土壤镉(Cd)的可交换态,并显著促进番茄幼苗的根长和鲜重,其中鲜重显著增长了79.23%(p<0.05)、根长显著增长了17.64%(p<0.05). 在液体培养基中,水苏糖能够显著促进BC18的生长,生物膜产生量相较于对照组显著增加了89.28%(p<0.05),产IAA能力显著提升,Cd的去除率提高至71.65%. 结果表明,Cd胁迫下,番茄幼苗可能通过释放水苏糖招募Massilia属的益生细菌,钝化土壤重金属Cd和促进植物生长的方式来协助植物抵御Cd胁迫. 研究结果可为通过调控根际微生物组来帮助植物抵御环境胁迫提供科学依据.

     

    Abstract: To further investigate how plant root secretions actively reshape the inter-root microbial community to enhance their own adversity tolerance, this study investigated the inter-root microecological effects and the mechanism of enrichment of probiotic bacteria by the differential inter-root secretion of fenugreek, under cadmium stress. The results showed that, at the genus level, fructose treatment significantly enriched bacteria of the genus Massilia, and its representative strain Massilia oculi CCUG 43427A (BC18) was successfully isolated. The results of the pot experiment indicated that BC18 significantly reduced the exchangeable state of soil cadmium (Cd) and significantly promoted the root length and fresh weight of tomato seedlings, in which the fresh weight increased significantly by 79.23% (p < 0.05) and the root length increased significantly by 17.64% (p < 0.05). In the liquid culture medium, the growth of BC18 was significantly enhanced by fructose application. The biofilm production was significantly increased by 89.28% (p < 0.05) compared with the control, the IAA-producing capacity was substantially improved, and the removal rate of Cd was increased to 71.65%. The results suggest that under the stress of cadmium pollution, tomato seedlings may assist the plant to resist Cd stress by releasing fucose to recruit probiotic bacteria of the genus Massilia, blunting soil heavy metal Cd and promoting plant growth. The study results may provide a scientific basis for helping plants to resist environmental stress by regulating the inter-root microbiome.

     

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