褪黑素处理对草地早熟禾抗盐性的影响

Effect of melatonin treatment on salt resistance of Poa pratensis

摘要:

【目的】 探究外源褪黑素对草地早熟禾（Poa pratensis）抗盐性的调节作用。【方法】 以草地早熟禾品种帝国为试验材料，测定浸种和外施褪黑素2种方法对种子萌发特性的影响，采用叶施和根施不同浓度褪黑素溶液处理幼苗，研究其对草地早熟禾生长和生理特性的影响。【结果】 浸种和外施褪黑素处理分别在其浓度为50、200 μmol/L时对盐胁迫下的草地早熟禾种子萌发效果最好；当褪黑素浓度为100、200 μmol/L时能够显著促进盐胁迫下草地早熟禾幼苗和根系的生长，积累幼苗干物质量和相对含水量，增加幼苗叶绿素含量，降低幼苗相对电导率和丙二醛含量，使得幼苗脯氨酸、可溶性糖和可溶性蛋白含量上升，并且在该浓度下叶施处理的效果更佳。【结论】 浓度为100、200 μmol/L的褪黑素溶液可以有效缓解盐胁迫对草地早熟禾幼苗的伤害，提高草地早熟禾的抗盐性。

Abstract:

【Objective】 To investigate the regulatory effect of exogenous melatonin on Poa pratensis under salt stress.【Method】 This experiment used the Poa pratensis ‘Empire’，as the material. The effects of seed soaking and external application of melatonin on seed germination characteristics under salt stress were studied. In addition，differ ent concentrations of melatonin were applied to the leaves and roots of seedlings to evaluate their effects on the growth and physiological characteristics of Poa pratensis under salt stress.【Result】 The results showed that soaking and external application of melatonin treatment had the best germination effect on Poa pratensis seeds under salt stress at concentrations of 50 μmol/Land 200 μmol/L respectively. At concentrations of 100 μmol/L and 200 μmol/ L，melantoninsignificantly promoted the growth of Poa pratensis seedlings and roots under salt stress，enhanced dry matter accumulation and relative water content，increased chlorophyll content，reduced relative conductivity and malo ndialdehyde （MDA） content，and elevated the contents of proline，soluble sugars，and soluble protein content of seed lings. Leaf application treatment within this concentration range was the most effective.【Conclusion】 In summary，ex ogenous melatonin concentration of 100 μmol/L and 200 μmol/L melatonin solution could effectively alleviate the damage of salt stress to Poa pratensis seedlings，improving the salt resistance and growth performance of Poa praten- sis.