The Effects Of Melatonin On Drought Tolerance And Growth Of Perennial Ryegrass

With the function of plant growth regulation and antioxidant,the use of melatonin in plants has caused the extensive concern.Moreover,the effect of melatonin on drought tolerance of perennial ryegrass(Lolium perenne)was not reported.In this research,we studied the effects of melatonin on drought tolerance and growth of perennial ryegrass.Research results were significant for improvement of drought tolerance of perennial ryegrass and the application of melatonin in plants.Resulted were shown as followed:(1)Seeds soaked with 25,50,75,100 and 200 μM melatonin solution improved germination potential,germination rate and water content of perennialryegrass under the conditions of drought stress,but not be observed under the normal conditions.(2)Seeds soaked with 25,50,75,100 and 200 μM melatonin solution improved plant water content,promoted the growth of above-ground biomass and underground biomass of perennial ryegrass on the seedling stage,moreover,root shoot ratio was be improved is important for drought tolerance of perennial ryegrass(3)25,50 and 75 μM melatonin pretreatment improved drought tolerance of perennial ryegrass.It was related with higher relative water content,lower electrolyte leakage,higher Fv/Fm,and slow decomposition rate of chlorophyll and carotinoid.And thenpretreatment with 100 μM melatonin decreased drought tolerance of perennial ryegrass.(4)25μM melatonin pretreatment improved the activity of SOD,CAT,POD enzymes andthe content of 2-Butenedioic acid,Isoleucine,Proline,Putrescine,Diethanolamine to enhance the ablity of osmotic adjustiment and antioxidiant.maintained the cell membrane stability,slow decomposition rate of chlorophyll and carotinoid andincreased drought tolerance of perennial ryegrass.