芒草对NaCl和PEG胁迫的生理响应及相关性分析

Physiological Responses of Miscanthus sinesis'Morning Light' to PEG and NaCl Stress and Their Correlations Analysis

采用不同浓度梯度的PEG模拟干旱和NaCl溶液胁迫室内盆栽的芒草,分析芒草幼苗含水量、叶绿素、保护酶系活性、渗透调节物质、膜脂过氧化产物及其之间的相关性,探讨芒草幼苗对PEG和NaCl胁迫的响应和耐干旱、耐盐能力。结果表明:芒草幼苗含水量对PEG胁迫比NaCl胁迫敏感,叶绿素则相反;CAT活性随着PEG和NaCl浓度的增加显著增强(P<0.05),POD活性在低浓度PEG(10%)和NaCl 6g/L、12g/L时达到最大,说明CAT和POD响应PEG和NaCl胁迫的活性存在差异;可溶性糖含量在PEG低浓度(10%)时最高,NaCl胁迫下的可溶性糖和MDA含量随盐浓度的增大显著升高(P<0.05),Pro含量随PEG和NaCl浓度的增大显著增加(P<0.05)。PEG胁迫下自由水含量与POD活性显著负相关,可溶性糖含量与POD活性显著正相关;NaCl胁迫下各生理指标的相关性高于PEG胁迫,可溶性糖含量与Pro和MDA含量极显著正相关,CAT活性与可溶性糖和MDA含量显著正相关。PEG和NaCl胁迫之间,CAT活性和Pro含量极显著正相关,说明芒草对干旱和NaCl胁迫会产生相关的生理适应机制。

Miscanthus sinesis＇Morning Light＇ planted in pots was stressed with PEG and NaCl of different concentration.The changes of cell membrane lipid peroxidation（MDA）,accumulation of osmolyte（soluble carbohydrate and free proline content）,protective enzyme activity（CAT,POD）,chlorophyll content and water content and their correlation were analyzed.The responsive ability of drought and salt resistance of M.sinesis＇Morning Light＇ seedlings were discussed in the study.The result showed that the response of water content of M.sinesis ＇Morning Light＇ seedlings to PEG was sensitive than that to NaCl,the response of chlorophyll content was different.The activity of CAT was increased significantly（P〈0.05）,the activity of POD was the highest with the low NaCl（6g/L、12g/L） stress,it indicated that the activity of CAT and POD to the PEG and NaCl stress was different.The content of soluble carbohydrate was the highest in low PEG stress（10%）,the content of soluble carbohydrate and MDA was increased significantly with the increased NaCl content（P〈0.05）,the content of Pro was increased significantly with the increased NaCl and PEG concentration（P〈0.05）.The free water content under PEG stress was negatively correlated with the activity of POD,and the soluble carbohydrate content was positively correlated with POD activity.The correlation among physiological indexes under NaCl stress was higher than that under PEG stress,the soluble carbohydrate content was positively correlated with Pro and MDA,the activity of CAT was positively correlated with soluble carbohydrate content and MDA.The activity of CAT was positively correlated with Pro content under both PEG stress and NaCl stress,It indicated that the M.sinesis ＇Morning Light＇ had relative philological adaptation mechanism to drought stress and NaCl stress.