NaCl胁迫对胡杨幼苗叶生理生化指标的影响

目的]研究不同NaCl浓度胁迫下胡杨幼苗叶生理生化指标变化特征,探讨胡杨幼苗的耐盐生理机制,为胡杨造林与资源的合理利用提供理论依据。方法]采用盆栽沙培,以2年生胡杨实生苗木为试验材料,设置5个NaCl浓度0.3%、0.6%、0.9%、1.2%和2%进行盐胁迫试验,测定胡杨幼苗叶片中脯氨酸(Pro)、可溶性蛋白、超氧化物歧化酶(SOD)、丙二醛(MDA)、Na~+、K~+和Cl~-的含量。结果]随着NaCI浓度的增加,胡杨幼苗叶片中脯氨酸、MDA、Na~+和Cl~-的含量增加,K~+含量和K~+/Na~+值降低,SOD活性和可溶性蛋白含量则呈先降低后上升的趋势。高盐处理对以上测定生理指标有较大影响。结论]NaCl胁迫下,胡杨幼苗叶片生理生化过程对盐分具有一定的适应性:(1)盐胁迫下,脯氨酸含量显著增加,是胡杨幼苗抵御盐胁迫重要的渗透调节物质;(2)盐胁迫下,可溶性蛋白明显降低,对胡杨幼苗抗盐胁迫贡献较小;(3)较高盐分浓度胁迫下,叶片中SOD活性增加,增强了胡杨幼苗抵御盐胁迫的能力;(4)在较低盐胁迫下,胡杨幼苗仍保持较高的K~+的吸收水平,具有一定的抗盐胁迫能力。

Effects of NaCl Stress on the Physiological and Biochemical Indexes in Seedling Leaves of Populus euphratica Oliv

【Objective】The effects of NaCl concentration on the physiological and biochemical characteristics in seedling leaves of Populus euphratica Oliv.were studied and the physiological mechanism of its salt tolerance was discussed,so as to provide the theoretical foundation for the afforestation and utilization of Populus euphratica Oliv.resources reasonably.【Method】The experiment set five NaCl concentration stress,which are 0.3%,0.6%,0.9%,1.2%and 2%,respectively.The two - year seedlings of Populus euphratica Oliv.were cultivated in sand - pot with NaCl - water irrigation and proline,soluble protein,the activities of SOD(superoxide dismutase),MDA(malondialdehyde) and the content of Na~+,K~+,CI~- in its leaves were measured.【Result】The content of proline,MDA,Na~+ and Cl~- were increased gradually with increasing NaCl salinity.Nevertheless,K~+ content and K~+ /Na~+ ratio were decreased.In contrast,the activities of SOD and soluble protein content decreased first and then increased with NaCl stress enhancement. The high NaCl salinity had significant effects on the measured physiological chemical indexes.【Conclusion】Under NaCl stress,physiological process in the seedling had somewhat adapted to salt stress,(1) under salt stress,the pro content increased significantly,therefore it was an important osmotic regulation substances for osmotic requilibrium in the leaves.(2) Salt stress and soluble protein in its leaves were decreased significantly by salt stress.(3) under salt stress,the activities of SOD was promoted,so it enhanced the seedling ability to enduring salt.(4) Under low salt stress,the seedling had a relative high level for absorbing K~+ to keep ionic requilibrium.