Du Buyun, Xia Ruizhi, Obrist Daniel, Sun Yufang, Wang Ting, Zhou Jun
College of Environmental Ecology, Jiangsu Open University, Nanjing 210017, China; Jiangsu Engineering and Technology Centre for Ecological and Environmental Protection in Urban and Rural Water Environment Management and Low Carbon Development, Nanjing 210017, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
J Hazard Mater. 2025 Aug 15;494:138524. doi: 10.1016/j.jhazmat.2025.138524. Epub 2025 May 6.
Understanding the plant uptake of atmospherically deposited cadmium (Cd) is limited. Factorial soil and atmospheric exposure experiments conducted in both field and greenhouse settings, in conjunction with stable Cd isotopes and synchrotron microscopic X-ray fluorescence (SR-μXRF), were performed to differentiate the impact of newly deposited Cd from legacy Cd in the soil. Root uptake of newly deposited Cd in soils contributed 43-48 %, 6.3-30 %, and 6.3-30 % to the leaves, stems, and grains, respectively. In contrast, foliar uptake contributed the most to rice leaves, which were subsequently limited in their translocation to stems and grains, accounting for 18-31 %, 5.7-12 %, and 5.7-11 % of Cd in leaves, stems, and grains, respectively. Stem nodes appear to restrict Cd translocation from leaves to grains while simultaneously facilitating both bi-directional xylem and phloem transport. Geochemical analyses and diffusive gradients in thin films extractions indicated that newly deposited Cd constituted the major bioavailable Cd fractions in soil solutions. In the rice growing season, the atmospherically deposited Cd only accounted 0.8-5.5 % of soil pools, but they substantially contributed 27-45 % to grains, raising important questions about how atmospheric Cd deposition may impact food security. The accumulation of Cd in rice grains from atmospheric deposition primarily occurs during the filling stage, making the management of emissions during this period crucial compared to the remediation of affected soils.
目前对植物吸收大气沉降镉（Cd）的了解有限。我们在田间和温室环境中进行了析因土壤和大气暴露实验，并结合稳定的Cd同位素和同步加速器微观X射线荧光（SR-μXRF）技术，以区分新沉积的Cd和土壤中遗留Cd的影响。土壤中新沉积Cd的根系吸收分别为叶片、茎和籽粒贡献了43%-48%、6.3%-30%和6.3%-30%。相比之下，叶面吸收对水稻叶片的贡献最大，随后向茎和籽粒的转运受到限制，分别占叶片、茎和籽粒中Cd的18%-31%、5.7%-12%和5.7%-11%。茎节似乎限制了Cd从叶片向籽粒的转运，同时促进木质部和韧皮部的双向运输。地球化学分析和薄膜扩散梯度萃取表明，新沉积的Cd是土壤溶液中主要的生物可利用Cd组分。在水稻生长季节，大气沉降的Cd仅占土壤库的0.8%-5.5%，但它们对籽粒的贡献高达27%-45%，这就引发了关于大气Cd沉降如何影响粮食安全的重要问题。大气沉降导致的Cd在水稻籽粒中的积累主要发生在灌浆期，因此与受影响土壤的修复相比，在此期间控制排放至关重要。
