title: Changes of organic acid exudation and rhizosphere pH in rice plants under chromium stress.
abstract: The effect of chromium (Cr) stress on the changes of rhizosphere pH, organic acid exudation, and Cr accumulation in plants was studied using two rice genotypes differing in grain Cr accumulation. The results showed that rhizosphere pH increased with increasing level of Cr in the culture solution and with an extended time of Cr exposure. Among the six organic acids examined in this experiment, oxalic and malic acid contents were relatively higher, and had a significant positive correlation with the rhizosphere pH, indicating that they play an important role in changing rhizosphere pH. The Cr content in roots was significantly higher than that in stems and leaves. Cr accumulation in plants was significantly and positively correlated with rhizosphere pH, and the exudation of oxalic, malic and citric acids, suggesting that an increase in rhizosphere pH, and exudation of oxalic, malic and citric acid enhances Cr accumulation in rice plants.
authors.affiliation: Department of Agronomy, College of Agriculture and Biotechnology, Huajiachi Campus, Zhejiang University, Hangzhou 310029, China.
authors.forename: Fanrong
authors.initials: F
authors.lastname: Zeng
authors.forename: Song
authors.initials: S
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Miao
authors.forename: Feibo
authors.initials: F
authors.lastname: Wu
authors.forename: Guoping
authors.initials: G
authors.lastname: Zhang
mesh_terms: D002857:Chromium / Q000032:analysis / Q000633:toxicity*; D003998:Dicarboxylic Acids / Q000378:metabolism*; D005506:Food Contamination; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D008293:Malates / Q000378:metabolism; D012275:Oryza / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D019815:Oxalic Acid / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D018526:Plant Transpiration; D012989:Soil Pollutants / Q000032:analysis / Q000633:toxicity*
chemical_list: D003998:Dicarboxylic Acids; D008293:Malates; D012989:Soil Pollutants; D002857:Chromium; C030298:malic acid; D019815:Oxalic Acid