title: Varietal differences in the growth of rice seedlings exposed to perchlorate and their antioxidative defense mechanisms.
abstract: A hydroponic experiment was conducted to investigate perchlorate (ClO4 (-) ) phytotoxicity in different rice varieties. Considerable variations were observed when 24 rice varieties were treated with ClO4 (-) . The shoot height, root length, and biomass of most varieties were significantly reduced by ClO4 (-) . The roots were more sensitive than the shoots. Hierarchical clustering analysis demonstrated primarily 4 groups: ClO4 (-) -sensitive, medium ClO4 (-) -sensitive, medium ClO4 (-) tolerant, and ClO4 (-) -tolerant. Gannuoxiang (a ClO4 (-) -tolerant variety) and IR65598-112-2 (a ClO4 (-) -sensitive variety) were chosen to explore their antioxidant response when exposed to 0.2 mmol/L, 2.0 mmol/L, and 4.0 mmol/L ClO4 (-) . The results showed that the activities of superoxide dismutase and catalase increased in the shoots and roots of gannuoxiang with increasing doses of ClO4 (-) , but both of them decreased at higher concentrations of ClO4 (-) in IR65598-112-2. The addition of ClO4 (-) led to a significant increase in peroxidase activities for both of the varieties, whereas the increase was more pronounced in gannuoxiang than in IR65598-112-2. No significant difference was found in malondialdehyde (MDA) contents in gannuoxiang, whereas the addition of ClO4 (-) increased the MDA level significantly in IR65598-112-2. The results indicated that gannuoxiang has higher activities of antioxidant enzymes than IR65598-112-2 to cope with oxidative damage caused by ClO4 (-) stress, which may be the main cause of its high tolerance.
authors.affiliation: Key Laboratory of Agro-Environment in the Tropics, South China Agricultural University, Ministry of Agriculture, Guangzhou, China.
authors.forename: Gui-Kui
authors.initials: GK
authors.lastname: Chen
authors.affiliation: Key Laboratory of Agro-Environment in the Tropics, South China Agricultural University, Ministry of Agriculture, Guangzhou, China.
authors.forename: Xiao-Bing
authors.initials: XB
authors.lastname: Li
authors.affiliation: Key Laboratory of Agro-Environment in the Tropics, South China Agricultural University, Ministry of Agriculture, Guangzhou, China.
authors.forename: Hong-Zhi
authors.initials: HZ
authors.lastname: He
authors.affiliation: Key Laboratory of Agro-Environment in the Tropics, South China Agricultural University, Ministry of Agriculture, Guangzhou, China.
authors.forename: Hua-Shou
authors.initials: HS
authors.lastname: Li
authors.affiliation: State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, China.
authors.forename: Ze-Min
authors.initials: ZM
authors.lastname: Zhang
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D016000:Cluster Analysis; D008315:Malondialdehyde / Q000378:metabolism; D012275:Oryza / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D010472:Perchlorates / Q000633:toxicity*; D010544:Peroxidases / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism; D018520:Plant Shoots / Q000187:drug effects / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000975:Antioxidants; D010472:Perchlorates; D008315:Malondialdehyde; D010544:Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; C494474:perchlorate
keywords: Growth parameters; Oryza sativa L; Oxidative stress; Perchlorate; Physiology