Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture and Rural Affairs/ Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture and Rural Affairs/ Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
J Environ Sci (China). 2023 May;127:577-588. doi: 10.1016/j.jes.2022.06.017. Epub 2022 Jun 18.
Soil salinity is known to improve cadmium (Cd) mobility, especially in arid soils. However, the mechanisms involved in how salt stress-associated metabolic profiles participate in mediating Cd transport in the soil-plant system remain poorly understood. This study was designed to investigate the effects of salinity-induced changes in soil metabolites on Cd bioavailability. Sodium salts in different combinations according to molar ratio (NaCl:NaSO=1:1; NaCl:NaSO:NaHCO=1:2:1; NaCl:NaSO:NaHCO:NaCO=1:9:9:1; NaCl:NaSO:NaHCO:NaCO=1:1:1:1) were applied to the Cd-contaminated soils, which increased soil Cd availability by 22.36% and the Cd content in wheat grains by 36.61%, compared to the control. Salt stress resulted in soil metabolic reprogramming, which might explain the decreased growth of wheat plants and increased Cd transport from the soil into wheat tissues. For example, down-regulation of starch and sucrose metabolism reduced the production of sugars, which adversely affected growth; up-regulation of fatty acid metabolism allowed wheat plants to maintain a normal intracellular environment under saline conditions; up-regulation of the tricarboxylic acid (TCA) cycle was triggered, causing an increase in organic acid synthesis and the accumulation of organic acids, which facilitated the migration of soil Cd into wheat tissues. In summary, salt stress can facilitate Cd transport into wheat tissues by the direct effect of salt-based ions and the combined effect of altered soil physicochemical properties and soil metabolic profiles in Cd-contaminated soils.
土壤盐分已知会提高镉（Cd）的迁移性，特别是在干旱土壤中。然而，盐胁迫相关代谢特征如何参与调节土壤-植物系统中 Cd 迁移的机制仍知之甚少。本研究旨在研究盐胁迫引起的土壤代谢物变化对 Cd 生物有效性的影响。根据摩尔比（NaCl：NaSO=1：1；NaCl：NaSO：NaHCO=1：2：1；NaCl：NaSO：NaHCO：NaCO=1：9：9：1；NaCl：NaSO：NaHCO：NaCO=1：1：1：1）将不同组合的钠盐应用于 Cd 污染土壤，与对照相比，土壤 Cd 有效性增加了 22.36%，小麦籽粒中的 Cd 含量增加了 36.61%。盐胁迫导致土壤代谢重新编程，这可能解释了小麦植株生长受阻和 Cd 从土壤向小麦组织迁移增加的原因。例如，淀粉和蔗糖代谢的下调减少了糖的产生，这对生长不利；脂肪酸代谢的上调使小麦植物在盐胁迫条件下能够维持正常的细胞内环境；三羧酸（TCA）循环的上调导致有机酸合成增加和有机酸积累，从而促进土壤 Cd 向小麦组织迁移。总之，盐胁迫可以通过盐基离子的直接作用以及 Cd 污染土壤中土壤理化性质和土壤代谢特征的综合变化，促进 Cd 向小麦组织的迁移。
