Guangdong Provincial Key Laboratory of Eco-Circular Agriculture, Guangzhou, 510642, China; College of Environmental Science and Engineering, China West Normal University, Nanchong, 637009, China; College of Resources and Environmental Sciences, South China Agricultural University, Guangzhou, 510642, China.
Guangdong Provincial Key Laboratory of Eco-Circular Agriculture, Guangzhou, 510642, China; College of Resources and Environmental Sciences, South China Agricultural University, Guangzhou, 510642, China.
Ecotoxicol Environ Saf. 2020 Dec 15;206:111184. doi: 10.1016/j.ecoenv.2020.111184. Epub 2020 Aug 26.
The potential toxicity of Cr to plants poses a severe threat to human health. Biochar and Se can reduce the absorption of Cr and its phytotoxicity in plants, but the associated mechanisms at subcellular levels have not been addressed in depth. A study was designed to investigate the effects of biochar, foliar application of Se, and their combination on the physicochemical and biological properties of the soil, Cr availability, Cr absorption, and Cr subcellular distribution in each part of the plant, and biomass and quality of two water spinach (Ipomoea aquatica) genotypes. The results showed that biochar, Se, and their combination increased the organic matter content and available NPK nutrients in the soil and improved the urease, phosphatase, catalase, and sucrase activities in the soil. Furthermore, they also increased the number of bacteria, actinomycetes, and fungi in the soil, were conducive to dry matter accumulation in I. aquatica, and increased the contents of soluble sugar and soluble protein in its leaves. The Cr contents in the roots and shoots of I. aquatica under different treatments were reduced compared with those in the control group. The content of Cr(VI) in the root-soil of I. aquatica with low Cr accumulation and the contents of Cr in various parts of I. aquatica were lower than those in I. aquatica with high Cr accumulation, and the absorbed Cr was mainly accumulated in the roots. Cr was mainly distributed in the cell walls and soluble fractions of the roots, stems, and leaves of I. aquatica and was less distributed in the organelles. Biochar and Se helped to increase the proportion of Cr in the cell walls of the roots and soluble fractions of the leaves of I. aquatica. The effects of improving the soil properties, passivating and inhibiting Cr absorption by I. aquatica, and reducing the Cr proportion in the organelles of biochar were superior to those of Se application. The foliar application of Se and biochar had no synergistic effect on inhibiting Cr absorption by I. aquatica. Based on these findings, the application of biochar in Cr-contaminated soil or foliar application of Se with low Cr-accumulating plants may be effective means of reducing the Cr absorption by plants and its toxicity to ensure the safe production of agricultural products in Cr-contaminated regions.
铬对植物的潜在毒性对人类健康构成严重威胁。生物炭和硒可以减少植物对铬的吸收及其毒性，但亚细胞水平上的相关机制尚未得到深入研究。本研究旨在探讨生物炭、叶面施硒及其组合对土壤理化性质和生物性质、铬有效性、铬吸收以及铬在植物各部分的亚细胞分布、两种蕹菜（Ipomoea aquatica）基因型生物量和品质的影响。结果表明，生物炭、硒及其组合增加了土壤有机质含量和有效氮磷钾养分，提高了土壤脲酶、磷酸酶、过氧化氢酶和蔗糖酶活性。此外，它们还增加了土壤中细菌、放线菌和真菌的数量，有利于蕹菜干物质积累，增加了叶片中可溶性糖和可溶性蛋白的含量。与对照组相比，不同处理下蕹菜根和地上部的铬含量均降低。低积累铬蕹菜根-土中 Cr(VI)含量和各部位铬含量均低于高积累铬蕹菜，吸收的铬主要积累在根部。铬主要分布在蕹菜根、茎、叶的细胞壁和可溶部分，细胞器中分布较少。生物炭和硒有助于增加铬在蕹菜根细胞壁和叶片可溶部分中的比例。改良土壤性质、钝化和抑制蕹菜对铬的吸收以及降低生物炭中铬在细胞器中的比例的效果优于硒的应用。叶面施硒和生物炭对抑制蕹菜对铬的吸收没有协同作用。基于这些发现，在铬污染土壤中应用生物炭或在低铬积累植物上叶面施硒可能是减少植物对铬的吸收及其对铬毒害的有效手段，以确保在铬污染地区安全生产农产品。
