Abstract: To explore the key physiological mechanism of Suaeda salsa (L.) Pall. adaptation to saline habitat, S. salsa was used as material artificial simulated salt and alkali stresses treatment method was adopted in this study. The growth index of S. salsa, the accumulation of organic acid and other solutes in roots and leaves were determined, and the physiological functional characteristics were analyzed. The results showed that salt stress did not affect the growth of S. salsa while alkali stress inhibited the growth of S. salsa. Organic acids were the main osmotic regulators (except Na⁺, K⁺) in roots and leaves of S. salsa under salt and alkali stresses. In terms of ion balance, Na⁺ and K⁺ were the main contributors to positive charge under salt and alkali stresses, while organic acids play a leading role in balancing positive charges in roots and leaves. Under salt and alkali stresses (especially under alkali stress), positive and negative charges were seriously unbalanced due to Na⁺ surge and anion deficiency, induced the synthesis of a large number of organic acids to ensure charge balance and stable pH. In conclusion, organic acids accumulated under salt and alkali stresses play a leading role in osmotic regulation, charge balance and pH regulation. Accumulation of organic acids is one of the most important survival strategies for S. salsa to adapt to salt-alkali stress.

Key words: Suaeda salsa, Salt and alkali stresses, Biomass, Organic acids, Na⁺/K⁺

摘要： 为探究碱蓬（Suaeda salsa（L.） Pall.）适应盐碱生境的关键生理机制，以盐地碱蓬为试验材料，采用人工模拟盐、碱胁迫的处理方法，测定其生长指标、根和叶片细胞液中有机酸等溶质积累并对其功能进行分析。结果表明：盐胁迫并不影响碱蓬的生长，而碱胁迫则抑制其生长。盐碱胁迫下有机酸为碱蓬根和叶片中主要的渗透调节物（除Na⁺，K⁺）。离子平衡方面，盐碱胁迫下，Na⁺和K⁺是正电荷的主要贡献者，而有机酸在平衡正电荷方面起主导作用。盐碱胁迫（尤其碱胁迫）由于Na⁺激增、阴离子亏缺，正负电荷严重失衡，诱导合成大量有机酸以保证电荷平衡和pH稳定。综上，盐碱胁迫下碱蓬积累的有机酸在渗透调节、电荷平衡及调节pH方面均起到主导作用。有机酸的积累是碱蓬适应盐碱胁迫重要的生存策略之一。

关键词: 盐地碱蓬, 盐、碱胁迫, 生物量, 有机酸, Na⁺/K⁺