Soil salinity hampers plant performance. Elevated atmospheric CO ([CO]) could alleviate the detrimental effect of salinity on plants but whether abscisic acid (ABA) is involved in this process is unclear. To address this issue, three tomato () genotypes with varying endogenous ABA concentrations (wild-type AC, ABA-deficient mutant and ABA-overproduction line SP5) were grown in pots under ambient (400 μmol · mol) or elevated (800 μmol · mol) CO with or without the addition of 100 mmol · Lsodium chloride (NaCl). The results showed that [CO] favored ion homeostasis by decreasing root-to-shoot delivery of Na, which was mainly attributed to lowered transpiration rate rather than altered xylem-sap Na concentration. In AC and SP5, the low transpiration rate of [CO]-plants under salinity was accompanied by enhanced endogenous ABA levels, which might play a role in upregulating the abundance of specific transcripts related to Na homeostasis (i.e., ) under salt stress. In , [CO]-induced Na homeostasis was abolished, which could be ascribed to the low and unaltered ABA levels, albeit the ethylene biosynthesis was enhanced in under salt stress, indicating an antagonistic relationship between ABA and ethylene. Furthermore, [CO] inhibited ethylene biosynthesis under salt stress in all three genotypes. The results enrich our comprehension of the fundamental processes of [CO]-conferred salt tolerance in tomato.

中文翻译：

---

番茄植株中二氧化碳赋予的钠稳态升高与脱落酸介导的气孔关闭和信号通路有关

土壤盐分会影响植物的生长。大气中二氧化碳（[CO]）升高可以减轻盐度对植物的有害影响，但脱落酸（ABA）是否参与这一过程尚不清楚。为了解决这个问题，将具有不同内源 ABA 浓度的三种番茄 () 基因型（野生型 AC、ABA 缺陷突变体和 ABA 过量生产系 SP5）在常温 (400 μmol·mol) 或高浓度 (800 μmol·mol) 条件下在盆中种植。 mol) CO，添加或不添加 100 mmol·L 氯化钠 (NaCl)。结果表明，[CO] 通过减少根部到地上部的 Na 输送来促进离子稳态，这主要是由于蒸腾速率降低而不是木质部汁液 Na 浓度的改变。在AC和SP5中，盐度下[CO]-植物的低蒸腾速率伴随着内源ABA水平的增强，这可能在盐胁迫下上调与Na稳态相关的特定转录本的丰度方面发挥作用。在[CO]诱导的Na稳态被消除的情况下，这可归因于ABA水平较低且未改变，尽管在盐胁迫下乙烯生物合成增强，表明ABA和乙烯之间存在拮抗关系。此外，[CO] 抑制所有三种基因型在盐胁迫下的乙烯生物合成。这些结果丰富了我们对[CO]赋予番茄耐盐性基本过程的理解。