title: Comparative phytotoxicity of Rac-metolachlor and S-metolachlor on rice seedlings.
abstract: The toxicity of Rac-metolachlor and S-metolachlor on rice (IIYou92, Oryza sativa L.) seedlings was determined and compared in a hydroponics experiment. The elongation of shoot, main root, and the number of lateral roots were inhibited in both Rac- and S-metolachlor treatments. The 96 h- IC50 of Rac- and S-metolachlor were 12.32 and 9.44 μM for shoot, and 4.69 and 1.75 μM for root, respectively. The content of chlorophyll a, chlorophyll b and total chlorophyll of leaf treated by Rac-metolachlor was higher than that treated by S-metolachlor. The activities of superoxide dismutase, peroxidase, cytochrome P450 2E1, glutathione S-transferase, and the content of glutathione increased after herbicide exposure, and the activities or the content was higher in the S-metolachlor treatment than in the exposure to Rac-metolachlor. Ultrastructural studies revealed that Rac- and S-metolachlor had adverse effects on leaf cells, and S-metolachlor treatment caused higher damage.
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, People's Republic of China. lhj@mail.zjgsu.edu.cn
authors.forename: Hui J
authors.initials: HJ
authors.lastname: Liu
authors.forename: Ming Y
authors.initials: MY
authors.lastname: Xiong
authors.forename: Bao L
authors.initials: BL
authors.lastname: Tian
mesh_terms: D000081:Acetamides / Q000737:chemistry* / Q000633:toxicity*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006540:Herbicides / Q000737:chemistry* / Q000633:toxicity*; D007536:Isomerism; D012275:Oryza / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
chemical_list: D000081:Acetamides; D006540:Herbicides; D010940:Plant Proteins; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; C051786:metolachlor