盐胁迫下山乌桕幼苗对施氮量的生理响应

Physiological Response of Sapium sebiferum Seedlings to Nitrogen Application Under Salt Stress

山乌桕利用价值高,开发前景广阔。以山乌桕为研究对象,分析了盐胁迫下山乌桕幼苗在不同施氮量处理下生理方面的变化,以期为沿海地区山乌桕高效栽培提供理论支撑。结果表明:在1~7 g/L NaCl处理下,山乌桕遭受了不同程度盐害,盐害率为2%~100%,盐害阈值为5 g/L NaCl。施氮影响了盐胁迫下供试幼苗叶片中含水率、叶绿素、丙二醛(MDA)、脯氨酸及可溶性糖含量的变化。其中,叶片含水率和叶绿素含量在轻度盐害(3 g/L NaCl)下,施用1.5 g/L尿素(含46%氮)能提升至无盐害处理(1 g/L NaCl)水平。在轻度和中度(5 g/L NaCl)盐害下,通过施用3 g/L尿素,MDA、脯氨酸含量显著降低。在重度(7 g/L NaCl)盐害下,施加3 g/L尿素增加了可溶性糖含量。研究可见,施氮能提升盐胁迫下山乌桕幼苗的光合和水分代谢能力,改善细胞膜透性及渗透调节功能,揭示了氮肥在提高山乌桕耐盐能力方面的应用潜力。

Sapium sebiferum has high utilization value and broad development prospect. Taking Sapium sebiferum as the research object, this experiment analyzed the physiological changes of Sapium sebiferum seedlings under salt stress under different nitrogen treatments, in order to provide theoretical support for high-efficiency cultivation of Sapium sebiferumin coastal areas. The results showed that under the treatment of 1 ~ 7 g/L NaCl, Sapium sebiferum suffered from different degrees of salt damage.The salt damage rate was 2% ~ 100%, and the salt damage threshold was 5 g/L NaCl. Nitrogen application affected the changes of water content, chlorophyll, malondialdehyde(MDA), proline and soluble sugar content in the leaves of the tested seedlings under salt stress. Among them, the leaf water content and chlorophyll content can be increased to the level of no salt damage treatment(1 g/L NaCl) by applying 1.5 g/L urea(containing 46% nitrogen) under mild salt damage(3 g/L NaCl). Under mild and moderate(5 g/L NaCl) salt injury, the MDA and proline contents were significantly decreased by applying 3 g/L urea. Under the severe(7 g/L NaCl) salt injury, applying 3 g/L urea increased the soluble sugar content. The results showed that nitrogen application could improve the photosynthetic and water metabolism capacity of Sapium sebiferum seedlings under salt stress, improve the membrane permeability and osmotic regulation functions, and reveal the potential of nitrogen application in improving the salt tolerance of Sapium sebiferum seedlings.