Effects of zinc oxide nanoparticles on arsenic stress in rice (Oryza sativa L.): germination, early growth, and arsenic uptake.

Abstract

This study describes the role of zinc oxide nanoparticles (ZnO NPs) in alleviating arsenic (As) stress in rice (Oryza sativa) germination and early seedling growth. Seeds of rice were primed with different concentrations (10, 20, 50, 100, and 200mgL-1) of ZnO NPs and As (0, and 2mgL-1) for 12days in petri dishes. Two milligrams per liter of As treatment represented a stress condition, which was evidenced by germination rate, seedling length, seedling dry weight, chlorophyll, superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) content of rice shoot. ZnO NPs amendment (10-100mgL-1) increased the germination rate (2.3-8.9%), shoot weight (18.2-42.4%), root weight (5.2-23.9%), and chlorophyll content (3.5-40.1%), while elevated the SOD (2.2-22.8%) and CAT (7.2-60.7%) activities and reduced the MDA content (17.5-30.8%). As concentrations were significantly decreased by 8.4-72.3% and 10.2-56.6%, respectively, in rice roots and shoots with ZnO NPs amendment (10-200mgL-1) by the As adsorption of ZnO NPs and promoted biomass of rice. All the amendments improved the Zn concentrations in rice shoots and roots. Overall, ZnO NPs provide effective resistance to arsenic toxicity by increasing germination, biomass, and nutrients of Zn and decreasing As uptake in rice.