盐胁迫对高寒草地牧草老芒麦幼苗生理指标的影响
Effect of Salt Stress on Physiological Characteristics of Alpine Grassland Pasture Elymus sibiricus

采用不同浓度(0、50、150、250 mmol·L-1)NaCl溶液处理萌发的老芒麦(Elymus sibiricus)幼苗，检测老芒麦在盐胁迫逆境下生理生化的变化。结果表明，随盐浓度增加，各供试材料的脯氨酸质量分数呈上升趋势(P<0.05)，叶绿素质量分数呈下降趋势(P<0.05)，而相对含水量、可溶性糖含量、超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性呈先升高后下降趋势(P<0.05)，150 mmol·L-1 NaCl浓度是其幼苗相对含水量和CAT活性的一个转折临界点。老芒麦幼苗期的相对含水量、叶绿素质量分数、可溶性糖质量分数、脯氨酸质量分数、SOD活性和CAT活性对盐胁迫浓度的变化响应灵敏，且在不同浓度盐胁迫下变化差异显著，其可作为快速鉴定老芒麦野生种质材料耐盐性的生理生化指标。熵值法综合评价不同浓度NaCl处理对老芒麦生理指标的影响表明，50 mmol·L-1NaCl最有利于老芒麦调控各生理指标，提高对盐胁迫的适应性，老芒麦适宜在青藏高原盐碱地和湖滨退化湿地的恢复改良中选用。
The growth parameters of Elymus sibiricus at early seedling stage were measured by four different concentrations of NaCl solutions (0, 50, 150, 250 mmol·L-1) and salt treatment was performed to explore and utilize the germplasm with high salt tolerance，so as to provide physiological indicators for identifying salt tolerance. The result showed that proline mass fraction increased with increase of salt concentration(P<0.05), chlorophyll mass fraction decreased in response to salt stress (P<0.05), relative water mass fraction, soluble sugar mass fraction, SOD and CAT enzyme activities increased at first and then declined later with increase of NaCl stress concentration (P<0.05). CAT enzyme activity had a critical turning point under the salt stress of 150 mmol·L-1.It was also obvious that the levels of relative contents of water, chlorophyll, soluble sugar, proline, SOD and CAT enzyme activities in the leaves at seedling stage were sensitive to the level of salt stress. And all of them could be used as physiological indicators for quick and accurate identification in salt tolerant wildrye germplasm. Soluble sugar mass fraction, proline mass fraction and CAT activity were relatively important physiological indicators of salt resistance of E.sibiricus. Entropy method for comprehensive evaluation of treatments of E.sibiricus with different salt concentrationsm the physiological characteristics showed that 50 mmol·L-1 NaCl was the most conducive to regulate physiological indexes of E.sibiricus, improve the adaptability to salt stress. Remarkable salt tolerance was detected about E.sibiricus, which had provided a basis for utilizing salt tolerant wildrye genetic resources.