STRESS ALLEVIATION POTENTIAL OF GRAPHENE OXIDE UPON EXPOSURE TO CADMIUM IN WHEAT

Abstract

Agriculture is widely recognized as the core foundation of the economy, significantly influencing the Gross Domestic Product (GDP) of a country. Wheat is among nutrient-rich grain that is crucial for ensuring food security. It plays an essential role in advancing Sustainable Development Goal (SDG) 2, i.e., “Zero Hunger”, adopted by the United Nations in 2015. However, wheat may experience certain biotic and abiotic stresses within environmental settings, with particular emphasis on heavy metal toxicity. In this regard, owing to the highly accumulative and toxic characteristics of cadmium (Cd), it emerges as a heavy metal of primary concern as it acts as a yield-limiting factor for wheat growth. The present study aimed to integrate nanotechnology in agriculture to alleviate Cd toxicity in wheat through a multi-dimensional design. Graphene oxide (GO) was synthesized via the modified Hummer’s method and went under various characterization techniques (SEM, EDS, XRD, and FTIR) to confirm the synthesis of nanoparticles. GO foliar application was carried out subsequently on wheat grown under Cd induced stress conditions (at 20 mg/kg and 40 mg/kg). GO at two distinct concentrations (30 mg/L and 60 mg/L) were applied during critical growth stages of wheat growth, i.e., 8th, 9th and 10th weeks of germination. Effects on cadmium accumulation in wheat tissues, physiological and biochemical parameters, including growth, chlorophyll content, and anti-oxidant activities were recorded, revealing that exogenous application of GO at 30 mg/L significantly improved (p < 0.05) the plant growth (plant height, spike length, shoot fresh and dry weight), physiological parameters (membrane stability index, relative chlorophyll content SPAD, relative water contents) and reduced Cd accumulation in wheat grains, shoots and roots. The findings of this study revealed dose-dependent nature of GO i.e., lower concentration (30 mg/L) demonstrates positive effects, while leading to toxicity at higher doses (60 mg/L). This work highlights significance of determining the concentration range of foliar application of nanoparticles in agriculture for enhancing the crop yield under heavy metals stress conditions, leading to sustainable agricultural practices in the era of the expected widespread application of nanotechnology.