盐分胁迫对景天三七幼苗生理生化特性的影响

采用不同盐分土壤(0.2%、0.4%、0.6%、0.8%、1.0%、1.2%)对景天三七幼苗进行胁迫处理,通过其生长情况、Na⁺和K⁺含量及生理生化特征,探讨景天三七耐盐性能及机理。结果表明,盐胁迫下,景天三七幼苗生理生化特性均有明显差异。≤0.4%盐分对景天三七幼苗生长具有促进作用,盐分浓度达到1.0%植株生长受到抑制。随着盐分浓度的增大,植物体内Na⁺含量有升高的趋势,Na⁺/K⁺比值逐渐增加;而SOD、CAT及POD活性总体呈先上升后下降趋势。同时,植物体内可溶性糖含量随着盐分浓度的增大显著升高,当盐分浓度为0.8%时达最大值;可溶性蛋白含量呈先升高后下降的趋势,且差异显著。叶绿素含量随盐浓度增大而减少,0.4%、0.6%和0.8%盐浓度下的叶片叶绿素含量比0.2%盐浓度下分别降低了11.5%、50.0%和79.9%。可见,≤0.4%盐分浓度可提高景天三七抗氧化酶活性,增强植物抗性,促进植物生长。

Effects of Salt Stress on Physiological and Biochemical Characteristics of Sedum aizoon Seedling

To explore the salt tolerance mechanism of Sedum aizoon seedlings, six salt gradients including 0.2%, 0.4%, 0.6%, 0.8%, 1.0% and 1.2% NaCl were conducted to determine their influence on seedling growth, content of Na⁺, K⁺, soluble sugar, soluble protein and chlorophyll, as well as the activity of SOD, CAT and POD. The results show that significant differences on physiological and biochemical characteristics are observed among S. aizoon seedlings under different salt stress conditions. When the salt concentration is no more than 0.4%, it could promote the growth of S. aizoon, while the salt concentration reaching 1.0% could inhibit the plant growth. As the increase of the salt concentration, the Na⁺ content and the Na⁺/K⁺ ratio increase gradually, whereas the activities of SOD, CAT and POD present a first increase and then decrease trend. The soluble sugar content in plants increases significantly with the increase of the salt concentration, reaching the maximum at 0.8% concentration. A trend of the soluble protein content of first increase and then decrease is observed with the increase of salt concentration. Meanwhile, the chlorophyll content has a continuous decreasing trend with the increase of the salt concentration. Compared with 0.2% salt concentration, chlorophyll content under 0.4%, 0.6% and 0.8% is decreased by 11.5%, 50.0% and 79.9%, respectively. Overall, when the salt concentration is no more than 0.4%, it can improve the salt stress resistance by enhancing the activity of antioxidant enzymes and then promote seedling growth of S. aizoon.