Melatonin-mediated resistance to copper oxide nanoparticles-induced toxicity by regulating the photosynthetic apparatus, cellular damages and antioxidant defense system in maize seedlings. (1st January 2023)

• Record Type: Journal Article
• Authors: Raza Khan, Ali; Fan, Xingming; Salam, Abdul; Azhar, Wardah; Ulhassan, Zaid; Qi, Jiaxuan; Liaquat, Fiza; Yang, Shuaiqi; Gan, Yinbo
• Is Part Of: Environmental pollution. Volume 316(2023)part 2
• Publication Date: 2023-01-01
• Subjects: Ultrastructure -- CuO NPs -- Melatonin -- Oxidative stress -- Maize -- Stomata; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2022.120639
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The pollution of nanoparticles (NPs) has linked with severe negative effects on crop productivity. Thus, effective strategies are needed to mitigate the phytotoxicity of NPs. The aim of present study was to evaluate the efficacy of exogenously applied melatonin (MT) in mitigating the toxic effects of copper oxide nanoparticles (CuO NPs) from maize seedlings. Therefore, we comprehensively investigated the inhibitory effects of MT against CuO NPs-induced toxicity on morpho-physiological, biochemical and ultrastructural levels in maize. Our results show that CuO NPs (300 mg L −1 ) exposure displayed significantly reduction in all plant growth traits and induced toxicity in maize. Furthermore, 50 μM MT provided maximum plant tolerance against CuO NPs-induced phytotoxicity. It was noticed that MT improved plant growth, biomass, photochemical efficiency ( Fv/Fm ), chlorophyll contents ( Chl a and Chl b ), SPAD values and gas exchange attributes (stomatal conductance, net photosynthetic rate, intercellular CO2 concentration and transpiration rate) under CuO NPs stress. In addition, MT enhanced the antioxidant defense system and conferred protection to ultrastructural (mainly chloroplast, thylakoids membrane and plastoglobuli) damages and stomatal closure in maize plants subjected to CuO NPs stress. Together, it can be stated that the exogenous supply of MT improves the resilience of maize plants against the CuO NPs-induced phytotoxicity. Our current findings can be useful for the enhancement of plant growth and yield attributes in CuO NPs-contaminated soils. The reported information can provide insight into the MT pathways that can be used to improve crop stress tolerance in a challenging environment. Highlights: Melatonin improved plant growth and biomass accumulation under CuO NPs stress. Melatonin inhibited ROS accumulation and enhanced maize antioxidant defense system. Melatonin reduced oxidative damage and improved photosynthetic efficiency. Melatonin inhibited H2O2 production and protected stomatal aperture under CuO NPs. Melatonin improved ultrastructure of maize seedlings exposed to CuO NPs stress.