Physiological Change of Six Wild Species in Elymus under Drought Stress at Seedling Stage

The seedlings of six wild species in Elymus were treated with drought stress,and their height,MDA,proline,and chlorophyll content were investigated.The results showed that the height was obviously reduced by drought stress.The growth rate of E.sibiricus was higher than others under no water stress.Furthermore,the drought stress had greater impact on the seedling growth of E.sibiricus and had less impact on the E.escelsus and E.purpuraristatus.With increasing drought stress,the relative water content and the total chlorophyll of all the materials decreased,while the MDA and Pro content increased.The leaf relative water content in XZD4 from Tibet decreased the lessest,E.escelsus and E.purpuraristatus from Xinjiang decreased the most;The MDA content in E.tangutorum and E.purpuraristatus increased more,while E.dahuricus and E.nutans increased less than others.The Pro content in E.purpuraristatus and E.nutans increased more.After rewatering,Pro content continued increasing,others restorated in different degrees.Through the hierarchical cluster analysis,the relative high resistance material was E.nutans,the moderate materials were E.escelsus and E.dahuricus,the low resistance materials were E.sibiricus,E.tangutorum and E.purpuraristatus.