Studies On Drought Tolerance Of Four Cool-Season Turfgrass

Drought resistance of lawn plant has the significant meaning on water-saving irrigation, and also provide a reference for the construction,maintenance and management of lawn.In this paper we took two varieties of Perennial Ryegrass 'Toya','Green Emerald',and two varieties of Kentucky bluegrass 'Kentucky','Midnight' as the experimental material,and studied the seed drought resistance in the germination stage under the osmotic stress of polyethylene glycol 6000.In the seedling stage,we studied the dynamic change of growth, appearance and physiological reaction of four lawn plants under the drought stress simulated with the PEG and drought stress in the natural soil,and evaluated the drought resistance ability of lawn plant comprehensively.The results were as following:(1)Under the osmotic stress with PEG,the relationships between four lawn grass seeds germination rate and the concentration of PEG were significant or very significant negative correlation.When concentration of PEG was 20%(intermediate drought stress),It is the most appropriated for identified seed drought resistance of lawn plant.Under the osmotic stress,the drought resistance for 'Green Emerald ' and 'Toya' are better in their seed stage.(2)In the seedling stage,under drought stress simulated with PEG,with PEG solution concentration increases,the RWC of four lawn plant is gradually decreased,while the RPP, Chl,Pro and MDA content were increased.The changes of soluble protein content are different of lawn plant under PEG stressing.There are significant differences Changes in Physiological indexes among difference lawn plant.From the correlation analysis,we can see that,under drought stress simulated by PEG,RWC and concentration of PEG solution show significant or very significant positive correlation,RPP,MDA and PRO and Concentration of PEG solution negative correlation of four lawn plant.(3)Under the soil natural drought stress,with the SWC decreased,Physiological reaction of four lawn plant seedlings are significantly change.The overall tendency for the changes of RWC,RPP,PRO,MDA of four lawn plant under soil natural drought stress are basically consistent with that under PEG drought stress simulated.From the correlation analysis,we can see that,under soil natural drought stress,RWC and SWC of four lawn plant show a significant or very significant negative correlation,RPP,MDA and PRO and SWC show a positive correlation.(4) By using the Membership Function analysis,drought resistance of four lawn plant under the two different stress modes were evaluated.The result indicated:the value of drought resistance of four lawn plan are in the same drought resistance interval,but the value of the same grass plants drought resistance exist a slight difference,the drought resistance order of four grass is 'Midnight'＞'Kentucky'＞'Green Emerald'＞Toya'.the final type of the drought resistance is divided into two categories:'Midnight' and 'Kentucky' are in middle drought resistance class.The 'Green Emerald' and 'Toya' are in weak drought resistance class.