Influences of drought stress on antioxidative activity and osmoregulation substance of Sonchus brachyotus DC.

To study the drought-resistant ability of Sonchus brachyotus DC.,physiological indexes of Sonchus branchyotus DC.seedlings were measured in drought Stress under pot culture experiments simulating different soil water regimes.Results showed that under water stress,relative water content(RWC) of leaves gradually decreased,while the permeability of plasma membrane and malondialdehyde(MDA) content increased.There was no significant difference between treatments and control under the light drought stress(P0.05).Catalase(CAT) activities were increased under drought stress.Activities of both superoxide dismutase(SOD) and peroxidase(POD) were initially increased but decreased slightly during drought stress.Both,however,were still higher than that of control.Free proline,soluble sugar and soluble protein contents continue to increase during drought stress.Proline content of treated seedlings was increased(11.06 times) compared with the control plants under severe drought stress.Results showed that Sonchus branchyotus DC.had high adaptability to drought stress.