Physiological resistance of three Lolium perenne L. varieties under PEG stress.

The effects of PEG stress on leaf proline content,relative water content,MDA content,superoxide dismutase(SOD) activity,and electrolyte leakage rate of three Lolium perenne L.varieties were investigated under treatments with different PEG concentrations.The results show that variety Premier was most resistant to osmotic stress and had the highest leaf relative water content,the least electrolyte leakage rate,and less increasing rates of MDA content under PEG stress,while the resistance of variety Fairway was the weakest.The proline accumulation in leaves of three varieties obviously increased under the PEG stress and Premier had stronger ability to resist PEG stress with rapid increasing in leaf proline contents.Superoxide dismutase(SOD) activities in leaves of three varieties increased during the initial stress stage at 5% PEG concentration and decreased continuously under severer stress.In summary,PEG stress resulted in the decreases in leaf relative water content and SOD activity and increases in leaf cell membrane permeability,MDA content,and proline accumulation of three L.prenne varieties and there was difference in the changing extents of the corresponding indices among three varieties.