Character Evaluation Of Different Perennial Ryegrass And Physiological Responses To Three Small Molecules Under Salt Stress

Perennial ryegrass has the characteristics of rapid seeds germination and quick lawn growth,which is often used as a pioneergrass or used for overseeding in our country climate transition zone.However,at present,in the production of large application is poor adaptability and stress-resistance.In this study,we researched 9 kinds of perennial ryegrass germplasm materials which were introduced from the United States in recent years.In the first place,we researched the adaptability of the nine materials in Nanjing area according to the National Turfgrass Evaluation Program(NTEP),we would screen out the species with good turf characters and adaptability.In the second place,through pot experiments,we studied the drought resistance and salt resistance of these materials.According to turf quality evaluation,we screened out the species with strong drought resistance and drought sensitive,strong salt resistance and salt sensitive.In the end,by spraying K2SO4,glycine betaine(GB),ascorbate(Asb)on leaves,we studied one of the salt sensitive species about the different physiological mechanisms of relieving salt injury.And we finally confirmed a suitable way to improve the salt resistance.The results showed that:(1)Under the same management conditions,the turf quality,coverage and density of the 9 perennial ryegrass all declined,and the leaves color turned yellow gradually,which may be connected with the high temperature and high humidity climate in summer and with the characteristics of these varieties themselves.Among the nine varieties,PR007 showed a relatively strong resistance,which could keep green for a period of time.The turf quality and coverage declined slowly.PR003,PR004,PR005 were poor growth performance.The turf quality declined quickly and the leaves turned yellow in the beginning of summer.(2)Under the same management conditions,drought stress and salt stress constrained the growth of the nine perennial ryegrasses in varying degrees.And all varieties ended up dead.Among the nine varieties,PR007 and PR009 can keep good growth during initial period of stress.Over time,turf quality decreased gradually,but the pace of decline were slower than others.PR005 was the most sensitive one to stress.The leaves turned yellow and the turf quality decreased rapidly.PR005 died earlier than other varieties in summer.(3)We studied the effects of K2SO4,GB,Asb under salt stress on the salt sensitive variety PR005.The results showed that spraying K2SO4,GB,Asb on leaves could improve the salt resistance by the way of ionic regulation,osmotic adjustment and antioxidant regulation.To a certain extent,these three methods could alleviate the damage caused by salt stress.These three methods restrained the decrease of TQ and RWC and the content increase of EL,MDA and Na+,improved the level of K+ in the leaves,reduced the decrease of CAT and APX seven days later.This study showed that,the effect of Asb to alleviate the salt stress was the most significant,and then were K2SO4 and GB.Above all,PR007 is the most suitable type in Nanjing grass cultivation,where PR007 is also the strong drought resistance and salt resistance.PR005 is the bad adaptability type and the drought sensitive and salt sensitive.If perennial ryegrasses were incurring salt-stress,splashing Asb could give a lot of help.