title: Do arbuscular mycorrhizal fungi affect cadmium uptake kinetics, subcellular distribution and chemical forms in rice?
abstract: Rice (Oryza sativa L.) plants were inoculated with two species of arbuscular mycorrhizal fungi (AMF) - Rhizophagus intraradices (RI) and Funneliformis mosseae (FM) and grown for 60days to ensure strong colonization. Subsequently, a short-term hydroponic experiment was carried out to investigate the effects of AMF on cadmium (Cd) uptake kinetics, subcellular distribution and chemical forms in rice exposed to six Cd levels (0, 0.005, 0.01, 0.025, 0.05, 0.1mM) for three days. The results showed that the uptake kinetics of Cd fitted the Michaelis-Menten model well (R(2)>0.89). AMF significantly decreased the Cd concentrations both in shoots and roots in Cd solutions. Furthermore, the decrement of Cd concentrations by FM was significantly higher than RI treatment in roots. AMF reduced the Cd concentrations markedly in the cell wall fractions at high Cd substrate (≥0.025mM). The main subcellular fraction contributed to Cd detoxification was cell wall at low Cd substrate (<0.05mM), while vacuoles at high Cd substrate (≥0.05mM). Moreover, the concentrations and proportions of Cd in inorganic and water-soluble form also reduced by AMF colonization at high Cd substrate (≥0.05mM), both in shoots and roots. This suggested that AMF could convert Cd into inactive forms which were less toxic. Therefore, AMF could enhance rice resistance to Cd through altering subcellular distribution and chemical forms of Cd in rice.
authors.affiliation: Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, and Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China. Electronic address: lihuizsu@126.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, and Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China.
authors.forename: Na
authors.initials: N
authors.lastname: Luo
authors.affiliation: Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, and Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China.
authors.forename: Li Jun
authors.initials: LJ
authors.lastname: Zhang
authors.affiliation: Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, and Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China.
authors.forename: Hai Ming
authors.initials: HM
authors.lastname: Zhao
authors.affiliation: Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, and Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China.
authors.forename: Yan Wen
authors.initials: YW
authors.lastname: Li
authors.affiliation: Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, and Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China.
authors.forename: Quan Ying
authors.initials: QY
authors.lastname: Cai
authors.affiliation: Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, and Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China; Consortium on Environment, Health, Education and Research (CHEER), and Department of Science and Environmental Studies, Hong Kong Institute of Education, Tai Po, Hong Kong SAR, PR China.
authors.forename: Ming Hung
authors.initials: MH
authors.lastname: Wong
authors.affiliation: Guangdong Provincial Research Center for Environment Pollution Control and Remediation Materials, and Guangzhou Key Laboratory of Environmental Exposure and Health, School of Environment, Jinan University, Guangzhou 510632, PR China. Electronic address: tchmo@jnu.edu.cn.
authors.forename: Ce Hui
authors.initials: CH
authors.lastname: Mo
mesh_terms: D002104:Cadmium / Q000378:metabolism*; D007700:Kinetics; D038821:Mycorrhizae / Q000378:metabolism*; D012275:Oryza / Q000378:metabolism* / Q000382:microbiology; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology; D018520:Plant Shoots / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism*; D013045:Species Specificity; D014018:Tissue Distribution
chemical_list: D012989:Soil Pollutants; D002104:Cadmium
keywords: Arbuscular mycorrhizal fungi; Heavy metal; Mechanism; Rice