Optimizing Brassica napus Resilience to Lead Toxicity: The Combined Effects of Fullerenol Nanoparticles and AMF on Antioxidant Systems

Abstract

Crop plants are severely affected by heavy metals (HMs) leading to food scarcity and economical loss. Lead (Pb) is outsourced by use of lead based fertilizers, lead batteries, mining, smelting and metal processing. It greatly reduced growth, development and yield of crops cultivated on contaminated sites. In this study, ameliorative role of carbon based fullerenol nanoparticles (FNPs) along with AMF inoculation was examined on Brassica napus L. grown in Pb contaminated soil. A pot experiment in 3 way completely randomize fashion with three replicates was conducted under natural conditions. For Pb stress, 200 µM PbCl2 solution was used at rate of 1 L per pot. Fullerenol nanoparticles (FNPs) were purchased from Sigma Aldrich and applied via foliar spray at 3 mM concentration. For AMF inoculation rhizospheric soil was colleccted from Sorghum bicolor fields and used in this experiment. Results of the study showed that Pb toxicity greatly reduced growth of B. napus plants. It lowered photosynthesis and gas exchange related attributes. Pb contamination caused oxidative stress, evident from elevated level of malondialdehye (MDA), lipid peroxidation and electrolytic leakage. It also triggered antioxidant defense system of B. napus. These plants also had high Pb metal ions in their root and shoot compared with control. Foliar application of FNPs along with AMF inoculation effectively mitigated oxidative stress caused by Pb and reduced its accumulation in root and shoot of B. napus plants. These treatments modulated phytosynthetic machinery, antioxidant defense mechanism and nutrients uptake in B. napus plants. It is concluded that use of carbon-based nano particles in combination with AMF can effectively mitigate HMs stress in crop plants grown in contaminated soil.