Key Laboratory for Agro-ecological Processes in Subtropical Region, Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China; Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Interdisciplinary Sciences Research Institute, Huazhong Agricultural Unifversity, Wuhan 430070, China.
Key Laboratory for Agro-ecological Processes in Subtropical Region, Changsha Research Station for Agricultural & Environmental Monitoring, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
J Hazard Mater. 2024 Dec 5;480:136302. doi: 10.1016/j.jhazmat.2024.136302. Epub 2024 Oct 28.
Zinc (Zn) and selenium (Se) are beneficial elements for crops, enhancing crop quality and alleviating heavy metal toxicity. However, there is limited research on the role of foliar Zn and Se in the mechanism of reducing cadmium (Cd) uptake in crops. A field experiment was conducted to investigate the effect on subcellular distribution, leaf antioxidant enzyme activities, and the transcriptional regulation in the process of Cd accumulation of rice grains after foliar applications of Zn, Se, and their mixed solutions (ZnSe). The results show that Zn and ZnSe reduced Cd content in the grains of three different rice (13.9 %-21.8 %/11.9 %-29.5 %) by enhancing the fixation capacity of Cd in the flag leaf by improving the binding efficiency between pectin and Cd in the cell wall. Increased flag leaf antioxidant enzyme activities further mitigated the toxic effects of Cd on rice, while Zn and ZnSe treatments upregulated genes related to metal-binding proteins and antioxidant enzymes and downregulated metal transport genes. This study systematically elucidates the mechanisms by which foliar application of ZnSe alleviates Cd toxicity through the regulation of gene expression and physiological functions, providing a theoretical basis for reducing Cd accumulation in rice and ensuring the safe production of food.
锌（Zn）和硒（Se）是作物有益的元素，可提高作物品质并减轻重金属毒性。然而，关于叶面喷施 Zn 和 Se 在降低作物吸收镉（Cd）中的作用机制的研究有限。本田间试验研究了叶面喷施 Zn、Se 及其混合溶液（ZnSe）对水稻籽粒亚细胞分布、叶片抗氧化酶活性和 Cd 积累过程中基因转录调控的影响。结果表明，Zn 和 ZnSe 通过提高细胞壁中果胶与 Cd 的结合效率，增强了 Cd 在功能叶中的固定能力，从而降低了三种不同水稻（籼稻、粳稻和杂交稻）籽粒中的 Cd 含量（13.9%-21.8%/11.9%-29.5%）。增加功能叶抗氧化酶活性进一步减轻了 Cd 对水稻的毒害作用，而 Zn 和 ZnSe 处理则上调了与金属结合蛋白和抗氧化酶相关的基因，并下调了金属转运基因。本研究通过基因表达和生理功能的调节，系统阐明了 ZnSe 叶面喷施缓解 Cd 毒性的作用机制，为降低水稻 Cd 积累、保障食品安全提供了理论依据。
