Alleviation of arsenic (III) toxicity in rice (Oryza sativa L.) by employingmonolayer protected modified silver nanoadsorbent: Insights into growthreconditioning with antioxidant defence

The present work imparts an efficient, simple and cost-effective nano-based technology for the removal of arsenic (III) from aqueous environment that was subsequently investigated on plant system for its evaluation. The study was designed to investigate the arsenic induced toxicity in rice cultivar MTU 7029 and its amelioration by monolayer protected silver nanoadsorbent under laboratory conditions. An efficient amelioration of arsenic induced toxicity was successfully achieved by the supplementation of nano-pretreated water ([~]97% arsenic free) in hydroponic culture medium of rice seedlings (MTU 7029). As (III) exposure in the growth medium declined the seedlings growth, physiological conditions as well as it disrupted antioxidant defence system by overproducing reactive oxygen species (ROS) and superoxide anions. However, the application of the nanoadsorbent exhibited the alleviation of As (III) toxicity through the improvement of seedlings growth, restoration of normal root morphology and anatomy as indicated by scanning electron microscopy (SEM) and histology; decreased level of root oxidizability, electrolyte leakage, hydrogen peroxide (H2O2), malondialdehyde (MDA) and proline content. Furthermore, the supplementation of nano-pretreated water in hydroponic culture medium of the rice seedlings showed improved level of antioxidant enzymes such as, catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione reductase (GR) and reduced level of ROS generation and superoxide anions formation as revealed by CM-H2DCFDA and DHE staining of the roots. Hence, the present findings conveying a successful amelioration of arsenic induced toxicity in rice plant could be a useful technique for the alternative use of irrigation water in the arsenic contaminated land.