The Differences Research On High Temperature Resistance And Drought Resistance Of Different Ryegrass Cultivars

To select fine ryegrass cultivars of the high temperature resistant and drought resistance and to explore the appraisal index and method and its mechanism of the high temperature resistant and drought resistance of ryegrass cultivars, thr13different ryegrass cultivars of Pinnacle, Premier, Night Shadow II,Pandora,Winter Green,Peak, Yaqing,Sords,Special High,Barwoltra,Oregon Tetraploid, Resist Rust King and McGrady were chosen in this research. The Changes of chlorophyll, content of MDA, proline, relative electric conductivity and peroxidase activity of these ryegrass cultivars in30℃,35℃,40℃of different high temperature treatment and25℃(control) temperature treatment have been determined,meanwhile the relative potential germination rate, relative germination'rate, relative germination index, relative vigor index,embryo root length/embryo bud length, chlorophyll content, content of MDA, proline content, relative electric conductivity and peroxidase activity in different PEG-6000concentration have been measured. The main research results are obtained as follows:1.The differences of germination rate and sprout rate among different ryegrass cultivars were a significant level or an extremely significant one. The average germination rate of ryegrass cultivars of lawn type are higher than the average germination rate of ryegrass cultivars of animal husbandry type. The average sprout rate of ryegrass cultivars of animal husbandry type are higher than the average sprout rate of ryegrass cultivars of lawn type. The leaf color, hairy leaves degree and wilting rate of different ryegrass cultivars have shown obvious differences which reach a significant or a very significant level. The average wilting rate of lawn type with ryegrass cultivars is lower than average wilting rate animal husbandry type with ryegrass cultivars, among them, wilting rate of lawn type with ryegrass cultivars Premier is the minimum rate only for the leaf tip withered and yellow and curly, and its high temperature resistance of the field performance is the strongest.2.The changes of chlorophyll content, content of MDA, proline content, relative electric conductivity and peroxidase activity of different ryegrass cultivars by different temperature treatment are obviously different with genetic differences of different ryegrass cultivars, which reach a significant or a very significant level. And, with treatment temperature were increased, the content of chlorophyll reduces, the relative electric conductivity increases, the content of MDA increases, the content of proline increases, the peroxidase activity of different ryegrass cultivars has been enhanced. According to the changes of chlorophyll content,relative electric conductivity,MDA content,proline content and peroxidase activity of different cultivars ryegrass with different temperature treatment, we can get the order of high temperature resistance of different ryegrass cultivars which is as follows:Yaqing>Night ShadowⅡ>Oregon Tetraploid>Pinnacle>Resist Rust King>Premier>Pandora>McGrady>Winter Green>Peak>Swords>Special High>Barwoltra.3. The changes of seed relative potential germination rate, relative germination rate, relative germination index and relative vigor index and embryo root length/embryo bud length of different PEG-6000concentration treatment in different ryegrass cultivars are obvious genetic different, all of which reach a significant or an extremely significant level. And, with the increasing of PEG-6000concentration, seed relative potential germination rate, relative germination rate, relative germination index and relative vigor index of different ryegrass cultivars are in decline. Different ryegrass cultivars under20%PEG-6000concentration stress have not radicle germ growth. Through adapting clustering the analysis of the sprout indicators of different ryegrass cultivars which are under20% PEG-6000stress concentration, this research has been found that the drought resistance performances of different ryegrass cultivars are that drought resistance of lawn type ryegrass cultivars such as Pinnacle, Night Shadow Ⅱ, Pandora and Peak is better, drought resistance of animal husbandry type with ryegrass cultivars Barwoltra, Oregon Tetraploid, Special High, Yaqing, Resist Rust King, McGrady, Swords and lawn type with ryegrass cultivar Premier is weaker.The drought resistance of lawn ryegrass cultivar Winter Green is the worst.4. The changes of chlorophyll content, content of MDA, proline content, relative electric conductivity and peroxidase activity of different PEG-6000concentration disposal in different ryegrass cultivars are obvious genetic different, which reach a significant or a very significant level. And, with the increasing of PEG-6000concentration, the content of chlorophyll reduces, the relative electric conductivity increases, the content of MDA increases, the content of proline increases, the peroxidase activity of different ryegrass cultivars has a trend of increasing at first then declining. According to the changes of chlorophyll content, relative electric conductivity, MDA content, proline content and peroxidase activity of different cultivars ryegrass in different PEG-6000concentration treatment, we think the drought resistance of lawn type with ryegrass cultivar Premier is stronger.