Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, Zhengzhou University of Light Industry, Zhengzhou 45000, China.
Henan Collaborative Innovation Center of Environmental Pollution Control and Ecological Restoration, Zhengzhou University of Light Industry, Zhengzhou 45000, China; Department of Chemistry, University of Camerino, Camerino (MC) 62032, Italy.
J Hazard Mater. 2021 Aug 5;415:125618. doi: 10.1016/j.jhazmat.2021.125618. Epub 2021 Mar 10.
Atmospheric deposition is the primary source of external environmental media for lead (Pb) influx in wheat grains. However, the mechanisms of Pb grain absorption remains unclear. We explored this mechanism through comparative experiments, involving defoliating leaf blades (TG) and a control group (CK) of field wheat after the anthesis stage. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis displayed that leaves and ears can directly absorb atmospheric deposition Pb through stomata. Compared with CK, the yield, grain Pb content, and grain Pb accumulation of TG wheat were significantly decreased by 13.25%, 22.10%, and 32.58%, respectively. Combined with the Pb isotope analysis, the ear had the highest contribution to grain Pb followed by leaf and root. Simultaneously, the absorption rate of grain Pb demonstrated a dynamic trend of "N" shape. Dominant contribution periods of the root, leaf, and ear organs to grain Pb accumulation were different. Unlike the root system, the contribution of the aboveground to grain Pb increased gradually, and the contribution of leaf and ear to grain Pb were mainly concentrated in the early and late filling stage, respectively. Our findings can provide a theoretical basis for the control of Pb pollution in grains.
大气沉降是小麦籽粒中铅（Pb）摄入的外部环境介质的主要来源。然而，Pb 粒吸收的机制仍不清楚。我们通过比较实验来探索这一机制，涉及开花后阶段的去叶叶片（TG）和田间小麦的对照组（CK）。扫描电子显微镜结合能量色散 X 射线光谱分析表明，叶片和麦穗可以通过气孔直接吸收大气沉降 Pb。与 CK 相比，TG 小麦的产量、籽粒 Pb 含量和籽粒 Pb 积累量分别显著降低了 13.25%、22.10%和 32.58%。结合 Pb 同位素分析，麦穗对籽粒 Pb 的贡献最高，其次是叶片和根。同时，籽粒 Pb 的吸收速率呈现出“N”形的动态趋势。根、叶和麦穗器官对籽粒 Pb 积累的主导贡献期不同。与根系不同，地上部分对籽粒 Pb 的贡献逐渐增加，而叶片和麦穗对籽粒 Pb 的贡献主要集中在灌浆初期和后期。我们的研究结果可为控制谷物中 Pb 污染提供理论依据。
