Zinc Oxide Nanoparticles (ZnONPs) as Nanofertilizer: Improvement on Seed Yield and Antioxidant Defense System in Soil Grown Soybean (Glycine maxcv. Kowsar)

Abstract

Herein, we investigated potential phytotoxicity of zinc oxide nanoparticles (ZnONPs) on seed yield, focusing on particle size-, morphology-, and concentration-dependent responses of multiple antioxidant defense biomarkers, in soil-grown soybean (Glycine max cv. Kowsar) during its lifecycle. To this end, we synthesized three types of morphologically unique ZnONPs (spherical/ 38nm, floral-like/ 59nm, and rod-like/ >500nm); all with high purity, triclinic crystal structure and negative surface charge; and compared the toxicity with Zn 2+ ions. Each pot received two seeds, placed in soil inoculated with N-fixing bacteria (Rhizobium japonicum) and grown outdoor for 120 days. Our findings demonstrated a significant particle size-, morphology-, and concentration-dependent influence of ZnONPs on seed yield, lipid peroxidation, and various antioxidant biomarkers in soybean. Our spherical 38nm ZnONPs were the most protective compared to the floral-like 59nm ZnONPs, rod-like >500nm ZnONPs, and Zn 2+ ions, particularly up to 160 mg/kg. However, at the highest concentration of 400 mg/kg, spherical 38nm ZnONPs elicited the highest oxidative stress responses (H2O2 synthesis, MDA, SOD, CAT, POX) in soybean compared to the other two morphologically different ZnONPs tested. The concentrationresponse curves for the three types of ZnONPs and Zn 2+ ions were nonlinear (nonmonotonous) for all the endpoints evaluated. The results also suggest differential nano-specific toxicity of ZnONPs compared to ionic Zn 2+ toxicity in soybean. Our higher NOAEL value of 160 mg/kg indicates the potential for ZnONPs to be used as a nanofertilizer for crops grown in Zn-deficient soils to improve crop yield, food quality and address malnutrition, globally.

Market Value of Nanotechnology-Based Products in Agriculture: Current Status and Future Sustainability Goals in the Era of Climate Change

“…Persoon) [57], dragonhead (Dracocephalum moldavica L.) [58], squash (Cucurbita pepo L.) [59], lettuce (Cucumis sativus L.) [60], soybean (Glycine max cv. Kowsar) [61] that increased yield and nutrition's of all these crops. Calcium NPs based 4 nano-enabled products are used for commercial purpose but these NPs not widely used as controlled-release nanocomposites, chelates, or fertilizer chemicals (Figure 5).…”

Bioaccumulation and phytotoxicity of ZnO nanoparticles in soil-grown Brassica chinensis L. and potential risks

“…Soil is considered as a major sink of ZnO NPs compared to atmospheric and aqueous ecosystems (Liu et al 2020, Rajput et al 2018. In recent years, ZnO NPs have been employed as a novel macronutrient nanofertilizer in the Zn de cient soil (Song &Kim 2020, Sun et al 2020, Yuse -Tanha et al 2020, as an antibacterial agent for plant protection (Singh et al 2018), as well as an effective agent for reducing metal uptake by plants (Rizwan et al 2019, Sharifan et al 2019a. ZnO NPs may enter the soil medium by direct (agricultural products) or indirect (biosolids) pathways, and then can be absorbed and accumulated by plants, causing an effect on plant growth (Zeb et al 2021).…”

“…Plants are essential components of various ecosystems (Balážová et al 2018, Yuse -Tanha et al 2020 and are prone to be directly in uenced by ZnO NPs in soils, posing possible risks to food safety and human health (Baskar et al 2020). From an ecological perspective, understanding the phytotoxicity and uptake of ZnO NPs in plant species is of signi cant importance (Zafar et al 2016).…”