Comparison of cold resistance of ZS-SJZ zoysiagrass and its new strains induced by 60Co-γ radiation

Study on cold resistance of ZS-SJZ zoysiagrass and its two new strains induced by 60Co-γ radiation， ZSS-50-1 and ZSS-60-2 was conducted under low temperature at 5℃，10℃，20℃ respectively. The cold resistance of the three zoysiagrasses was evaluated by measuring proline content，relative electrical conductivity，soluble total sugar content，superoxide dismutase（SOD）activity and malondialdehyde（MDA）content of leaves，and the turfgrass coverage and color were observed. The results showed that the proline content，leaf relative electrical conductivity， soluble sugar content，MDA content and SOD activity of the three zoysiagrasses showed an higher trend with the decrease of temperature stress，whereas the turfgrasses coverage and color ratings were reduced. Under 5℃ treatment， the proline content，relative electrical conductivity，soluble total sugar content and MDA content of the new turfgrass strains were greater than those of ZSS zoysiagrass，while the SOD activity was lower than that of ZSS zoysiagrass. Using the method of subordinate function weights coefficient of standard deviation the cold resistance of the three zoysiagrasses was comprehensively evaluated，the order of cold resistance ability was ZSS-50-1 ＞ ZSS ＞ ZSS-60-2.