A Comprehensive Evaluation Of Tolerance To Drought Of Seven Varieties Of Turfgrass Ground Cover Plants

Test single factor completely randomized design, drought stress and rewatering conduct are conducted on the Ophiopogon [(Ophiopogon japonicas), respectively:MD-3, MD-4, MD-5, MD-6, MD-7, MD-8] and Kentucky bluegrass (Poa pratensis L., abbreviated KB) 7 kinds of lawn ground cover plants, discussing drought stress and rewater on nine physiological biochemical indicators effects, included leaf relative water content, chlorophyll, soluble protein (SP), membrane permeability, malondialdehyde (MDA), free proline (Pro), catalase (CAT), superoxide dismutaseand catalase (SOD) and peroxidase (POD), and using clustering methods and membership function to cluster and comprehensively evaluate on drought resistance of seven kinds of lawn ground cover plants. The results as follows:(1) Under drought stress, the leaf relative water content of seven kinds of lawn ground cover plants decrease at last. After rewatering, the leaves relative water content of seven kinds lawn ground cover plants were increased.(2) Under mild drought stress, the chlorophyll content of seven kinds of lawn ground cover plants were increased, with the further extension of the stress time, the chlorophyll content of seven kinds of lawn ground cover plants decline. After rewatering, the chlorophyll content of seven kinds of lawn ground cover plants were increased.(3) Under drought stress, conductivity of 7 kinds of lawn ground cover plants were increased. After rewatering, conductivity of MD-7,MD-8 and KB and three kinds of lawn ground cover plants were declined.(4) With the increase of the number of days of drought, MDA content of seven kinds of lawn ground cover plants were increased. After rewatering, MDA content of MD-7 and KB were declined.(5) With the extension of drought stress time, proline content of seven kinds of lawn ground cover plants were increased, the accumulation reach the maximum under severe stress. After rewatering, proline content of MD-3, MD-6, MD-7, MD-8 and KB of five kinds of lawn ground cover plants are still on upward trend.(6) Under mild stress, the SP content of seven kinds of lawn ground cover plants were increased, under moderate and severe stress, SP content were decreased. After rewatering, the SP content of seven kinds of lawn ground cover were increased.(7) Under drought stress, SOD, POD and CAT activities trends of seven kinds of lawn ground cover plants are first increased and then decreased, in which SOD activity of MD-6 is the highest, POD activities of MD-5 is the highest, CAT activity of MD-4 is highest, the strength of protective enzyme activity of seven kinds of turf ground cover plants are not the same,performance are not the same either. After rewatering, seven kinds of lawn ground cover plants SOD, POD and CAT activity were increased.(8) the ability of tolerance to drought of 7 kinds of lawn ground cover plants of the 15th d and 23rd d were leveled:MD-4> MD-3> MD-5> MD-7> KB> MD-8> MD-6; MD-4> MD-3> MD-5> MD-8> MD-7> MD-6.(9) Seven kinds of lawn ground cover plants using group average clustering into three categories:drought of MD-4 is the strongest, clustered into a single class; drought resistance of MD-3, MD-5, KB, MD-7 and MD-8 are in the mindle and clustered together; drought resistance of MD-6 is the weakest and clustered together.CONCLUSION:With the prolonged drought stress time, lawn quality and leaf relative water content significantly were decreased; Ch1 content, SP content, CAT activity, SOD activities, POD activities first increased and then declined; membrane permeability, MDA content, Pro content were significantly increased of seven kinds of lawn ground cover plants. After rewatering, indicators of seven kinds of lawn ground cover plants had diferent degrees of recovery. In addition, drought resistance of seven kinds of lawn ground cover plants exist differences, drought resistance of MD-4 was the strongest; drought resistance of MD-3, MD-5, MD-7, MD-8 and KB were in tne middle; drought resistance of MD-6 was the weakest, the comprehensive order of drought resistance in order of seven kinds lawn ground cover plants of the drought stress 15th d and first 38rd d were:MD-4> MD-3> MD-5> KB> MD-7> MD-8> MD-6.