Ma Chuanxin, Hao Yi, Zhao Jian, Zuverza-Mena Nubia, Meselhy Ahmed G, Dhankher Om Parkash, Rui Yukui, White Jason C, Xing Baoshan
Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou 510006, China.
The Connecticut Agricultural Experiment Station, New Haven, CT 06504, USA.
Nanomaterials (Basel). 2021 Mar 25;11(4):839. doi: 10.3390/nano11040839.
The present study investigated the role of graphitic carbon nitride (CN) in alleviating cadmium (Cd)- and arsenic (As)-induced phytotoxicity to rice ( L.). A high-temperature pyrolysis was used to synthesize the CN, which was characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, and dynamic light scattering. Rice seedlings were exposed to CN at 50 and 250 mg/L in half-strength Hoagland's solution amended with or without 10 mg/L Cd or As for 14 days. Both Cd and As alone resulted in 26-38% and 49-56% decreases in rice root and shoot biomass, respectively. Exposure to 250 mg/L CN alone increased the root and shoot fresh biomass by 17.5% and 25.9%, respectively. Upon coexposure, Cd + CN and As + CN alleviated the heavy metal-induced phytotoxicity and increased the fresh weight by 26-38% and 49-56%, respectively. Further, the addition of CN decreased Cd and As accumulation in the roots by 32% and 25%, respectively, whereas the metal contents in the shoots were 30% lower in the presence of CN. Both As and Cd also significantly altered the macronutrient (K, P, Ca, S, and Mg) and micronutrient (Cu, Fe, Zn, and Mn) contents in rice, but these alterations were not evident in plants coexposed to CN. Random amplified polymorphic DNA analysis suggests that Cd significantly altered the genomic DNA of rice roots, while no difference was found in shoots. The presence of CN controlled Cd and As uptake in rice by regulating transport-related genes. For example, the relative expression of the Cd transporter in roots was upregulated by approximately threefold with metal exposure, but CN coamendment lowered the expression. Similar results were evident in the expression of the As transporter in roots. Overall, these findings facilitate the understanding of the underlying mechanisms by which carbon-based nanomaterials alleviate contaminant-induced phyto- and genotoxicity and may provide a new strategy for the reduction of heavy metal contamination in agriculture.
本研究调查了石墨相氮化碳（CN）在减轻镉（Cd）和砷（As）对水稻（Oryza sativa L.）诱导的植物毒性中的作用。采用高温热解法合成了CN，并通过透射电子显微镜、傅里叶变换红外光谱和动态光散射对其进行了表征。将水稻幼苗置于添加或不添加10 mg/L Cd或As的半强度霍格兰氏溶液中，分别用50和250 mg/L的CN处理14天。单独的Cd和As分别导致水稻根和地上部生物量降低26 - 38%和49 - 56%。单独暴露于250 mg/L的CN分别使根和地上部鲜生物量增加了17.5%和25.9%。共同暴露时，Cd + CN和As + CN减轻了重金属诱导的植物毒性，鲜重分别增加了26 - 38%和49 - 56%。此外，添加CN分别使根中Cd和As的积累量降低了32%和25%，而在有CN存在的情况下，地上部的金属含量降低了30%。As和Cd也显著改变了水稻中的大量元素（K、P、Ca、S和Mg）和微量元素（Cu、Fe、Zn和Mn）含量，但在与CN共同暴露的植物中这些变化不明显。随机扩增多态性DNA分析表明，Cd显著改变了水稻根的基因组DNA，而地上部未发现差异。CN的存在通过调节与转运相关的基因来控制水稻对Cd和As的吸收。例如，根中Cd转运蛋白的相对表达在金属暴露时上调了约三倍，但CN共同添加降低了该表达。根中As转运蛋白的表达也有类似结果。总体而言，这些发现有助于理解碳基纳米材料减轻污染物诱导的植物毒性和基因毒性的潜在机制，并可能为减少农业中的重金属污染提供新策略。
