title: Stability of Chloropyromorphite in Ryegrass Rhizosphere as Affected by Root-Secreted Low Molecular Weight Organic Acids.
abstract: Understanding the stability of chloropyromorphite (CPY) is of considerable benefit for improving risk assessment and remediation strategies in contaminated water and soil. The stability of CPY in the rhizosphere of phosphorus-deficient ryegrass was evaluated to elucidate the role of root-secreted low molecular weight organic acids (LMWOAs) on the dissolution of CPY. Results showed that CPY treatments significantly reduced the ryegrass biomass and rhizosphere pH. The presence of calcium nitrate extractable lead (Pb) and phosphorus (P) suggested that CPY in the rhizosphere could be bioavailable, because P and Pb uptake by ryegrass potentially provided a significant concentration gradient that would promote CPY dissolution. Pb accumulation and translocation in ryegrass was found to be significantly higher in P-sufficient conditions than in P-deficient conditions. CPY treatments significantly enhanced root exudation of LMWOAs irrigated with P-nutrient solution or P-free nutrient solution. Oxalic acid was the dominant species in root-secreted LMWOAs of ryegrass under P-free nutrient solution treatments, suggesting that root-secreted oxalic acid may be the driving force of root-induced dissolution of CPY. Hence, our work, provides clarifying hints on the role of LMWOAs in controlling the stability of CPY in the rhizosphere.
authors: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of the Environment, Nanjing Normal University, Nanjing, 210023, China.|Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing, 210023, China.|Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, 210023, China.
authors: Wei
authors: W
authors: Wei
authors: School of Resources and Environment, Anqing Normal University, Anqing, 246011, China.
authors: Yu
authors: Y
authors: Wang
authors: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of the Environment, Nanjing Normal University, Nanjing, 210023, China.
authors: Zheng
authors: Z
authors: Wang
authors: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of the Environment, Nanjing Normal University, Nanjing, 210023, China.
authors: Ruiming
authors: R
authors: Han
authors: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of the Environment, Nanjing Normal University, Nanjing, 210023, China.
authors: Shiyin
authors: S
authors: Li
authors: Jiangsu Provincial Key Laboratory of Materials Cycling and Pollution Control, School of the Environment, Nanjing Normal University, Nanjing, 210023, China.|Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing, 210023, China.|Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing, 210023, China.
authors: Zhenggui
authors: Z
authors: Wei
authors: Department of Geographical Sciences, University of Alabama, Tuscaloosa, AL, 35487, United States of America.
authors: Yong
authors: Y
authors: Zhang
mesh_terms: D008129:Lolium / Q000737:chemistry / Q000378:metabolism*; D008903:Minerals / Q000737:chemistry* / Q000378:metabolism; D008970:Molecular Weight; D009930:Organic Chemicals / Q000737:chemistry / Q000378:metabolism*; D019815:Oxalic Acid / Q000737:chemistry / Q000378:metabolism*; D010710:Phosphates / Q000737:chemistry* / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000378:metabolism*; D058441:Rhizosphere
chemical_list: D008903:Minerals; D009930:Organic Chemicals; D010710:Phosphates; C469846:chloropyromorphite; D019815:Oxalic Acid