Collaborative Innovation Centre for Grain Industry, College of Agriculture, Yangtze University, Jingzhou 434025, China.
Institute of Crop Science, Zhejiang University, Hangzhou 310058, China.
Int J Mol Sci. 2020 Oct 29;21(21):8058. doi: 10.3390/ijms21218058.
Cadmium (Cd) contamination in soils poses great risks to both agricultural production and human health. Calcium (Ca) is an essential element playing a significant role in protecting plants against Cd toxicity. However, how Ca affects Cd uptake and translocation in rice is still not fully elucidated. In this study, the regulatory role of Ca in Cd uptake and upward translocation was investigated in rice at different growth stages. Our results showed that the supplement of 5 mM Ca significantly reduced Cd uptake by rice roots, because of their competition for Ca-permeable channels as an absorption site and Ca-induced downregulation of and . However, Ca application facilitated the upward translocation of Cd by both upregulating to induce xylem loading of Cd and downregulating to reduce vacuolar sequestration of Cd. Such contrary results suggested a double-edged role of Ca in regulating root Cd uptake and root-to-shoot Cd translocation in rice. Although it increased Cd content in the aboveground vegetative tissues during the whole growth period, the addition of 5 mM Ca eventually decreased Cd content in rice grains at the ripening stage. All these results suggest that Ca-based amendments possess great potential for the production of low-Cd rice grains.
土壤中的镉（Cd）污染对农业生产和人类健康构成了巨大威胁。钙（Ca）是一种重要的元素，在保护植物免受 Cd 毒性方面发挥着重要作用。然而，Ca 如何影响水稻对 Cd 的吸收和转运仍未完全阐明。在这项研究中，我们在不同的生长阶段研究了 Ca 对水稻吸收和向上转运 Cd 的调节作用。结果表明，补充 5 mM Ca 显著降低了水稻根系对 Cd 的吸收，这是因为 Ca 与根系吸收位点上的 Ca 可透性通道竞争，以及 Ca 诱导 和 的下调。然而，Ca 的应用通过上调 来诱导 Cd 向木质部装载，以及下调 来减少 Cd 在液泡中的隔离，从而促进了 Cd 的向上转运。这些相反的结果表明 Ca 在调节水稻根系对 Cd 的吸收和根到茎的 Cd 转运方面具有双重作用。虽然 Ca 处理在整个生长期间增加了地上营养组织中的 Cd 含量，但在成熟阶段，添加 5 mM Ca 最终降低了水稻籽粒中的 Cd 含量。所有这些结果表明，基于 Ca 的改良剂在生产低 Cd 含量的稻谷方面具有巨大的潜力。
