Growth Hormone-like Activities of Organophosphorus Flame Retardants (OPFRs) in growth of Rice (Oryza sativa L.)

Abstract To identify the toxic effect of Organophosphorus Flame Retardants (OPFRs) on plants, six different OPFRs involved in three concentrations (50 µg/L, 100 µg/L and 200 µg/L) were selected to estimate their toxicity to rice growth. The seed germination, seedling growth, OPFRs accumulation and antioxidative defense system were investigated in rice. The results showed that all of OPFRs inhibited the germination of seeds. OPFRs were accumulated in roots and shoots, and the accumulations of OPFRs in roots were higher than in shoots. However, the hormone-like effect of all six OPFRs was found on plants. The growth of seedlings was irrigated by 50 µg/L, 100 µg/L and 200 µg/L OPFRs in our experiment according to fresh weights and lengths of seedlings. And then malondialdehyde (MDA) and antioxidative defense system were impressed after OPFRs exposed 21 d. According to gene expressions of seven antioxidative enzymes at 14 d, most of enzyme expressions were updated to alleviated reactive oxygen species (ROS) by OPFRs exposure. Tris (1, 3-dichloro-2-propyl) phosphate (TDCPP) showed the strongest oxidative toxicity to plants among all of OPFRs. During the early 14 d period, the antioxidant enzymes could play important role in detoxification process. And after 21 d, antioxidants ascorbate (AsA) in roots and glutathione (GSH) in shoots could take over antioxidant enzymes against to OPFRs toxicity.