The effect of Odontothrips loti damage on AsA, GSH content and metabolic enzyme activities in alfalfa plants
Author of the article:KOU JiangTao1,2**SHI ShangLi1,2***HU GuiXin1,2
Author's Workplace:1. College of Grassland Science, Gansu Agricultural University, Lanzhou730070, China;2. Key Laboratory of Ecosystem Ministry of Education, Pratacultural Engineering Laboratory of GansuProvince, SinoUS Center for Grazingland Ecosystem Sustainability, Lanzhou730070, China
Key Words:alfalfa, Odontothrips loti, ascorbic acid, reduced glutathione, ascorbate peroxidase, glutathione reductase, insect resistance
Abstract:The function of nonenzymatic antioxidant ascorbic acid (AsA), reduced glutathione (GSH) and metabolic enzymes ascorbate peroxidase (APX) and glutathione reductase (GR) on the resistance of alfalfa to thrip damage were investigated. AsA and GSH contents, and the activities of APX and GR in resistant and susceptible alfalfa clones, R1 and I1, grown under different thrip densities, were measured. For R1 treatments, AsA, GSH contents and GR activity increased under low thrip densities (1, 3 per branch), while under high densities (5,7 per branch), AsA content and GR activity first increased then decreased, while GSH content initially increased then remained stable. For I1 treatments, AsA and GSH contents first increased then decreased, and GR activity displayed a tendency to increase during the late damage stage. APX activities for both clones increased at first and then decreased, but the amplitude of the fluctuation for R1 was less than that for I1, indicating that AsA and GSH content, and APX and GR activity, might be a form of resistance induced in alfalfa by thrip damage, with the response of I1 to such damage lagging behind that of R1. During the later damage stage, AsA and GSH content and APX and GR activity in the R1 clones remained at a high level, indicating that R1 plants had a greater capacity than I1 to resist thrip damage.