Graphitic Carbon Nitride (C 3 N 4 ) Reduces Cadmium and Arsenic Phytotoxicity and Accumulation in Rice ( Oryza sativa L.)

• Published in: Nanomaterials (Basel, Switzerland) Vol. 11; no. 4; p. 839
• Main Authors: Ma, Chuanxin, Hao, Yi, Zhao, Jian, Zuverza-Mena, Nubia, Meselhy, Ahmed G, Dhankher, Om Parkash, Rui, Yukui, White, Jason C, Xing, Baoshan
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 25.03.2021; MDPI
• Subjects: Accumulation; Agricultural pollution; Agricultural production; Agriculture; Aquatic plants; Arsenic; Bioavailability; Biomass; Cadmium; Carbon; Carbon nitride; Contaminants; Contamination; Copper; Crops; Deoxyribonucleic acid; DNA; Electron tubes; Exposure; Fourier transforms; g-C3N4; Genotoxicity; Heavy metals; High temperature; Infrared radiation; Infrared spectroscopy; Investigations; Light scattering; Magnesium; Manganese; Nanomaterials; Nanotechnology; Nitrogen; Oryza sativa; Photon correlation spectroscopy; Physiology; Phytotoxicity; Polymerase chain reaction; Pyrolysis; Quantum dots; Random amplified polymorphic DNA; Reduction (metal working); Rice; Roots; Seedlings; Seeds; Shoots; synthesis; Transmission electron microscopy; Zinc; Zinc oxides; United States > US; g-C3N4; synthesis; accumulation; cadmium; arsenic; rice; metal transporters
• ISSN: 2079-4991; 2079-4991
• DOI: 10.3390/nano11040839

The present study investigated the role of graphitic carbon nitride (C N ) in alleviating cadmium (Cd)- and arsenic (As)-induced phytotoxicity to rice ( L.). A high-temperature pyrolysis was used to synthesize the C N , which was characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, and dynamic light scattering. Rice seedlings were exposed to C N 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 C N alone increased the root and shoot fresh biomass by 17.5% and 25.9%, respectively. Upon coexposure, Cd + C N and As + C N alleviated the heavy metal-induced phytotoxicity and increased the fresh weight by 26-38% and 49-56%, respectively. Further, the addition of C N 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 C N . 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 C N . 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 C N 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 C N 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.