Rather than high pH or Na⁺, excess bicarbonate, by inducing over-accumulation of organic acids (through dark fixation) in plant roots, was hypothesized to be the main growth-limiting factor under alkali salt stress. Thus, the effect of four treatments viz. control (pH 6.0), high pH (9.0), high pH (9.0) plus sodium sulfate (25 mM) and sodium bicarbonate (50 mM, pH 9.0) on growth, gas exchange and leaf water content, organic acid accumulation, ion relations, oxidative damage and changes in the expression of key genes was investigated in Vicia faba. The bicarbonate treatment showed the highest growth reduction, PEPCase gene expression and accumulation of citrate and malate in roots. Bicarbonate treated plants preferentially accumulated Fe²⁺ and Ca²⁺ in roots and reduced root exudation of citrate and malate. Moreover, these plants experienced K⁺ and Ca²⁺ deficiencies, which caused a massive increase in H₂O₂ concentration in leaves and roots, leading to severe oxidative damage. Bicarbonate treated plants showed reduced levels of PM H⁺-ATPase, SOS1, CS, and MDH gene expression in roots. The cascade of events confirms the hypothesized central role of organic acid accumulation in bicarbonate induced stress, making bicarbonate more detrimental to plant growth than high pH or its combination with sodium salt.

与高 pH 值或 Na ^{+ 不同}，过量的碳酸氢盐通过诱导植物根部有机酸的过度积累（通过暗固定）被认为是碱盐胁迫下的主要生长限制因素。因此，四种治疗的效果即。控制 (pH 6.0)、高 pH (9.0)、高 pH (9.0) 加硫酸钠 (25 mM) 和碳酸氢钠 (50 mM, pH 9.0) 对生长、气体交换和叶片含水量、有机酸积累、离子关系的影响在蚕豆中研究了氧化损伤和关键基因表达的变化。碳酸氢盐处理显示出最高的生长减少、PEPCase基因表达以及柠檬酸盐和苹果酸盐在根中的积累。碳酸氢盐处理的植物优先积累 Fe ²⁺和Ca ²⁺，减少根系中柠檬酸盐和苹果酸盐的渗出。此外，这些植物经历了K ⁺和Ca ²⁺缺乏，导致叶子和根中H ₂ O ₂浓度大量增加，导致严重的氧化损伤。碳酸氢盐处理的植物显示出根中PM H ⁺ -ATPase、SOS1、CS和MDH基因表达水平降低。一系列事件证实了假设的有机酸积累在碳酸氢盐诱导的胁迫中的核心作用，使碳酸氢盐比高 pH 值或其与钠盐的组合对植物生长更有害。