Biochemical Characters of Lolium perenne under High Temperature Stress

Heat stabilities of three Lolium perenne cultivars were compared under simulated high temperature stress in an artificial climate incubator.Six indices of biochemical characters(plasma membrane permeability,chlorophyll content,proline contents,malondialdehyde(MDA) contents,peroxidase(POD) activities and superoxide dismutase(SOD) activities) were measured at day and night temperatures of 38℃/28℃.These results suggested that leaf relative conductivity and free proline and MDA contents of tested grasses increased with the increase of high temperature stress and had a positive correlation with the time of high temperature stress.The chlorophyll content decreased,whereas both POD and SOD activities increased first then decreased under high temperature stress.In conclusions,cultivar Neruda has the best ability of heat resistance and there was no obvious distinction of heat resistance between cultivars Caliente and Charger Ⅱ.