Graphitic Carbon Nitride (C3N4) Reduces Cadmium and Arsenic Phytotoxicity and Accumulation in Rice (Oryza sativa L.)

Abstract

The present study investigated the role of graphitic carbon nitride (C3N4) in alleviating cadmium (Cd)- and arsenic (As)-induced phytotoxicity to rice (Oryza sativa L.). A high-temperature pyrolysis was used to synthesize the C3N4, which was characterized by transmission electron microscopy, Fourier-transform infrared spectroscopy, and dynamic light scattering. Rice seedlings were exposed to C3N4 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 C3N4 alone increased the root and shoot fresh biomass by 17.5% and 25.9%, respectively. Upon coexposure, Cd + C3N4 and As + C3N4 alleviated the heavy metal-induced phytotoxicity and increased the fresh weight by 26–38% and 49–56%, respectively. Further, the addition of C3N4 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 C3N4. 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 C3N4. 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 C3N4 controlled Cd and As uptake in rice by regulating transport-related genes. For example, the relative expression of the Cd transporter OsIRT1 in roots was upregulated by approximately threefold with metal exposure, but C3N4 coamendment lowered the expression. Similar results were evident in the expression of the As transporter OsNIP1;1 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.

g-C3N4promotes agro-ecosystem productivity: a case study for rice

“…15,16 Several studies have now found that the addition of g-C 3 N 4 can reduce the toxicity of heavy metals such as cadmium and arsenic in the soil through chemical and biological pathways, ensuring the normal growth of crops such as rice. 17,18 Based on these properties, we hypothesized that soil amendment of g-C 3 N 4 could promote the plant photosynthesis, antioxidant capacity, soil nutrient cycling, crop yields, etc. A recent report showed that g-C 3 N 4 can enhance the photosynthesis in maize during the seed germination period.…”

Nanoenabled Enhancement of Plant Tolerance to Heat and Drought Stress on Molecular Response

“…Due to the unique physicochemical characteristics, quantum effects, and large surface area, nanomaterials (NMs) have been used in many fields such as food chemistry, catalysis, , medical, , environmental, , pollution remediation, − and energy. , In recent years, nanoagriculture has emerged as a potential application area for NMs. , NMs have been investigated for their possible application in agriculture as nanofertilizers, ,− nanopesticides, ,− growth regulators, biosensors, and targeted transporters. ,, With considerable advancements in the synthesis and characterization of NMs as well as a greater mechanistic knowledge of nanomaterial–plant interactions, the application of nanotechnology in agriculture has grown significantly over the past 10 years. The development of highly specialized, even responsive, nanomaterials and their fine-tuning have enormous potential as a long-term approach to agricultural enhancement.…”

Root Exposure of Graphitic Carbon Nitride (g-C3N4) Modulates Metabolite Profile and Endophytic Bacterial Community to Alleviate Cadmium- and Arsenate-Induced Phytotoxicity to Rice (Oryza sativa L.)

“…23 Similarly, Ma et al reported that g-C 3 N 4 significantly ameliorated Cd-and As-induced phytotoxicity to rice in hydroponics and lowered the Cd and As accumulation in rice via modulating the expression of genes associated with Cd and As transporters. 24 However, the efficacy of g-C 3 N 4 in metal(loid)-contaminated agricultural soil remains unknown, as is the associated mechanisms of action. In comparison with a hydroponic system, soil provides a more realistic environment for plant growth upon coexposure to g-C 3 N 4 and metal(loid)s. The potential interaction of g-C 3 N 4 and soil altered plant nutrient and metal(loid) uptake and subsequently affected metal(loid)-induced phytotoxicity.…”