title: Arsenic dynamics in the rhizosphere and its sequestration on rice roots as affected by root oxidation.
abstract: A pot experiment was conducted to investigate the effects of root oxidation on arsenic (As) dynamics in the rhizosphere and As sequestration on rice roots. There were significant differences (P < 0.05) in pH values between rhizosphere and non-rhizosphere soils, with pH 5.68-6.16 in the rhizosphere and 6.30-6.37 in non-rhizosphere soils as well as differences in redox potentials (P < 0.05). Percentage arsenite was lower (4%-16%) in rhizosphere soil solutions from rice genotypes with higher radial oxygen loss (ROL) compared with genotypes with lower ROL (P < 0.05). Arsenic concentrations in iron plaque and rice straw were significantly negatively correlated (R = -0.60, P < 0.05). Genotypes with higher ROL (TD71 and Yinjingruanzhan) had significantly (P < 0.001) lower total As in rice grains (1.35 and 0.96 mg/kg, respectively) compared with genotypes with lower ROL (IAPAR9, 1.68 mg/kg; Nanyangzhan 2.24 mg/kg) in the As treatment, as well as lower inorganic As (P < 0.05). The present study showed that genotypes with higher ROL could oxidize more arsenite in rhizosphere soils, and induce more Fe plaque formation, which subsequently sequestered more As. This reduced As uptake in aboveground plant tissues and also reduced inorganic As accumulation in rice grains. The study has contributed to further understanding the mechanisms whereby ROL influences As uptake and accumulation in rice.
authors: Institute of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China; College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha 410128, China. Electronic address: ploki10@163.com.
authors: Weisong
authors: W
authors: Pan
authors: Institute of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China. Electronic address: wuchuan@csu.edu.cn.
authors: Chuan
authors: C
authors: Wu
authors: Institute of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China.
authors: Shengguo
authors: S
authors: Xue
authors: Crop and Environment Sciences Department, Harper Adams University, Newport, Shropshire, TF10 8NB, United Kingdom.
authors: William
authors: W
authors: Hartley
mesh_terms: D001151:Arsenic / Q000737:chemistry*; D005838:Genotype; D007501:Iron / Q000032:analysis; D012275:Oryza / Q000737:chemistry* / Q000502:physiology; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D018517:Plant Roots / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil; D007501:Iron; D001151:Arsenic; D010100:Oxygen
keywords: arsenic; iron plaque; radial oxygen loss; rhizosphere; rice