The Comparative Study Of Salt Tolerance For Perennial Ryegrass At Seed Germination, Seedling Growth And Establishment Stage

Present study determined the effect of temperature and salinity on plant performance at seed germination, seedling growth and establishment stage in six varities of perennial ryegrass, further, regression analysis and subordinate function were applied to fully evaluate the salt resistance. The main results were as follows:1. Temperature, variety and salt concentration significantly affected the relative germination rate, relative germination index, relative root length, seedling height, biomass, leaf number per plant and seedling survival rate. As salt concentration increasing, the above indexes showed a decreasing trend.2. Salt resistance at germination stage varied with temperatures, all varieties showed the strongest salt resistance at 15/25 ℃, followed by 25/35 ℃, and 5/15 ℃. For example, the half lethal salt concentration at 5/15 ℃, 15/25 ℃, 25/35 ℃ was-0.75 MPa,-1.68 MPa and-1.04 MPa, respectively. The relative performance of salt resistance among varieties also varied with testing temperature, such as the best varities regarding to salt resistance at 5/15 ℃, 15/25 ℃, 25/35 ℃ were Esquire, Medalist and Emerald, and the the worst were Medalist, Neruda and Neruda, respectively.3. Salt resistance at seedling growth stage is closely related to incubation temperature. For example, the half depressed salt concentration for shoot growth at 5/15 ℃, 15/25 ℃, 25/35 ℃ were-0.53 MPa,-0.91 MPa,-0.59 MPa, respectively, while half depressed salt concentration for root were-0.38 MPa,-0.54 MPa,-0.41 MPa, respectively. The relative performance of salt resistance among varieties also varied with incubation temperature, such as the best varities regarding to salt resistance at 5/15 ℃, 15/25 ℃, 25/35 ℃ were Gray Star, Gray Star and Esquire, respectively, while the worst were Esquire, Neruda and VNS.4. Plant relative biomass,density, height and seedling survival rate of all varities declined as salt concentration increasing at seedling establishment stage. The best variety regarding to salt resistance is Emerald, while the worst is Neruda.5. Comprehensive evaluation based on subordinate function analysis, the salt resistance capacity of six varities from strong to weak: Gray Star > Medalist >Esquire> Emerald > VNS > Neruda.