Study On The Sensitivity To Mesotrione In Setaria Glauca(L.)Beauv. And Setaria Faberii Herrm.

Both Setaria glauca(L.)Beauv. and Setaria faberii Herrm, distributed all over China, belong to Setaria Genera, Gramineae family, They are annual or perennial weed infesting corn field , orchard and roadside, and causing corn yield loss by interfere with corn for fertilizer, water and light. Mesotrione is the most important herbicide in triketone herbicides and nowadays it is widely used in corn field because the high control efficacy, wide spectrum and safety to corn. It is found in the field experiments that species of Setaria spp. varies in tolerant abilities to mesotrione. In this paper,two main species of Setaria spp. were selected to study the sensitivity to the herbicide in phytotoxicity symptoms, HPPD gene sequence, chloroplasts pigment and GSTs by bioassay, molecular technology and physiological and biochemical method with the main results :1. The results from the greenhouse study showed that Setaria glauca(L.)Beauv. was more sensitive than Setaria faberii Herrm to mesotrione with the GR50 of 180.8 g a i·ha^-1 ,nearly 5 times of that of Setaria faberii.2. Amplified 589 base pairs of the Hydroxylphenylacetoneacidsynthase (HPPD) without any intron and derived 141 amino acid sequences from Setariaglauca(L.)Beauv.and Setaria faberii Herrm..3. The determination of chloroplasts pigment revealed that the chloroplasts pigment of Setaria glauca(L.)Beauv. decreased quickly than Setaria faberii Herrm.. The chloroplasts pigment of Setaria faberii Herrm. restored the original level 14 DAT.4. GSTs activity analysis for Setaria glauca(L.)Beauv.and Setaria faberii Herrm. demonstrated that the GSTs activity of Setaria faberii Herrm was higher than Setaria glauca(L.)Beauv. in the untreated plants with OD₃₄₀nm values 0.8⁰.85 and 0.6⁰.65 ,respectively.When treated with mesotrione, the GSTs relative activity of Setaria glauca(L.)Beauv. and Setaria faberii Herrm increased. The OD340nm values of Setaria glauca(L.)Beauv. decreased in 7 DAT.But the OD340nm values of Setaria faberii Herrm maintained higher level until 9 DAT, decreased obviously in 14 DAT and restored in 21DAT.The results gain from the study may help to expain the differences of sencitivity in Setaria glauca(L.)Beauv.and Setaria faberii Herrm to mesotrione and promote the management of herbicide tolerant weed in corn field.