Chromium phytoextraction and physiological responses of the hyperaccumulator Leersia hexandra Swartz to plant growth-promoting rhizobacterium inoculation  

作　　者：Xuehong Zhang Yuanyuan Zhang Dan Zhu Zhiyi Lin Na Sun Chang Su Hua Lin Junjian Zheng 

机构地区：[1]College of Life and Environmental Science,Guilin University of Electronic Technology,Guilin 541004,China [2]College of Environmental Science and Engineering,Guilin University of Technology,Guilin 541004,China [3]College of Mathematics and Science,Wuhan Institute of Technology,Wuhan 430205,China

出　　处：《Frontiers of Environmental Science & Engineering》2023年第1期99-110,共12页环境科学与工程前沿（英文）

基　　金：supported by the National Natural Science Foundation of China(Nos.52000046,52100034,52170154,and 52070051);the Special Project of Guangxi Science and Technology Base and Talent(Nos.GuiKe AD20297009 and GuiKe AD20297007);the Middle-aged and Young Teachers’Basic Ability Promotion Project of Guangxi(Nos.2020KY05039 and 2021KY0221).

摘　　要：Phytoextraction is a promising option for purifying hexavalent chromium(Cr(Ⅵ))-laden wastewater,but the long remediation period incurred by poor growth rate of Cr hyperaccumulators remains a primary hindrance to its large-scale application.In this study,we performed a hydroponic experiment to evaluate the feasibility of promoting the growth and phytoextraction efficiency of Cr hyperaccumulator Leersia hexandra Swartz(L.hexandra)by inoculating plant growth-promoting rhizobacteria(PGPR)Bacillus cereus(B.cereus).In batch tests,the Cr(Ⅵ)removal rates of L.hexandra and B.cereus co-culture were greater than the sum of their respective monocultures.This was likely due to the microbial reduction of Cr(Ⅵ)to Cr(Ⅲ),which is amiable to plant uptake.Besides,the PGPR factors of B.cereus,including indoleacetic acid(IAA)production,1-aminocyclopropane-1-carboxylic acid deamination(ACCd)activity,phosphate solubilization capacity,and siderophore production,were quantified.These PGPR factors helped explain the biomass augmentation,root elongation and enhanced Cr enrichment of the inoculated L.hexandra in pot experiments.Despite the increased Cr uptake,no aggravated oxidative damage to the cell membrane was observed in the inoculated L.hexandra.This was attributed to its capacity to confront the increased intracellular Cr stress by upregulating both the activities of antioxidative enzymes and expression of metal-binding proteins/peptides.Moreover,L.hexandra could always conserve the majority of Cr in the residual and oxalic integrated forms with low mobility and phytotoxicity,irrespective of the B.cereus inoculation.These results highlight the constructed Cr hyperaccumulatorrhizobacteria consortia as an effective candidate for decontaminating Cr(Ⅵ)-laden wastewater.

关 键 词：Hexavalent chromium HYPERACCUMULATOR RHIZOBACTERIA Leersia hexandra Swartz Bacillus cereus Consortia 

分 类 号：X173[环境科学与工程—环境科学]