Abstract: To compare the salt tolerance of two tall fescue cultivars ('Titanium 2LS' and 'Easycare'),we treated the two cultivars with 500 mmol·L^-1 NaCl for 14 days and measured the morphological indexes,ion content,photosynthetic parameters to further compare the tolerance of the two species of tall fescue seedlings to salt stress. The results showed that the above-ground biomass and below-ground biomass of both tall fescue species were significantly reduced under salt stress (P<0.05),but the below-ground biomass of 'Titanium 2LS' was reduced less than that of 'Easycare';the K⁺/Na⁺ of both tall fescue species decreased significantly (P<0.05) under 500 mM salt stress,but the change of 'Easycare' was more significant;the soluble sugar and proline contents in two tall fescue seedlings increased. In addition,photosynthetic parameters and fluorescence parameters of the two species decreased significantly,and SOD activity decreased significantly,but the decrease of 'Titanium 2LS' was smaller than that of 'Easycare';POD activity did not change significantly between the two species of tall fescue,but the POD activity of 'Titanium 2LS' showed an increasing trend and that of 'Easycare' showed a decreasing trend. In conclusion,under salt stress,'Titanium 2LS' could maintain relatively high K⁺/Na⁺ and better photosynthetic capacity,accumulate more proline and soluble sugar to alleviate the injury,and alleviate osmotic stress,ionic toxicity,and oxidative stress induced by salt stress,thus it is more advantageous to the plant growth. Therefore,the salt tolerance of 'Titanium 2LS' is better than that of 'Easycare'.

Key words: Tall fescue, Salt stress, Ion content, Photosynthetic characteristics, Antioxidase activity

摘要： 本研究以两个高羊茅(Festuca arundinacea Schreb.)品种'钛极-2LS’(Festuca arundinacea'Titanium 2LS’)和'易凯’(Festuca arundinacea'Easycare’)幼苗为研究对象，通过盐浓度递增的方式对其进行14 d高盐处理(500 mmol·L^-1 NaCl)，测定两个高羊茅品种幼苗的形态、离子含量、光合参数以及抗氧化酶活性等指标，比较其耐盐性差异。结果表明：在盐胁迫下，两个高羊茅品种幼苗地下生物量，K⁺/Na⁺，光合、荧光参数，超氧化物歧化酶活性均显著降低(P＜0.05)，但'钛极-2LS’的降低幅度低于'易凯’；两个高羊茅品种幼苗内可溶性糖和脯氨酸含量增加，但'钛极-2LS’的增加幅度高于'易凯’；此外，盐胁迫下过氧化物酶活性在'钛极-2LS’中呈上升趋势而在'易凯’中呈下降趋势。综上，盐胁迫下'钛极-2LS’可以维持相对较高的K⁺/Na⁺和较好的光合能力，积累更多渗透调节物质来缓解盐胁迫引起的渗透胁迫、离子毒害和氧化胁迫的伤害，从而更有利于植株生长，因此'钛极-2LS’耐盐性更好。

关键词: 高羊茅, 盐胁迫, 离子含量, 光合特性, 抗氧化酶活性