Effect of nano zinc oxide and zinc chloride on some nutrients concentration, protein and oil content of soybean (Glycine max L.) seeds

Effect of nano zinc oxide and zinc chloride on some nutrients concentration, protein and oil content of soybean (Glycine max L.) seeds

Zinc is an essential micronutrient that plays a key role in a numerous of physiological processes of plants, thus bioenrichment of zinc can be effective to improve plant growth and seed quality. In this study, we synthesize three sizes of zinc oxide nanoparticles (38, 59, and 500 nm) with high purity, and assessed the potential influence of particle size and concentration (0, 50, 100, 200, and 500 mg/kg soil) of ZnONPs on seed oil and protein content, and seed N, P, K, and Zn concentration during the whole growth period of soybean plant (120 days), and compared them with the soluble Zn2+ ions and water-only controls. We observed particle size- and concentration-dependent influence of ZnONPs on oil and protein content, and N, P, K, and Zn concentration in soybean seeds. Overall, soybean responses to the smallest size of ZnONP-38 nm were greater for all parameters tested compared to the two larger-sized ZnONPs (ZnONP-59, ZnONP 500) and Zn2+ ions treatments up to 200 mg/kg. Whereas with increasing concentration (500 mg/kg), all traits tested showed a decreasing trend compared to the control, except the amount of seed Zn. Seed TEM images also showed the size of protein storage vacuoles and oil bodies in the seed embryo of plants treated with 500 mg/kg of ZnONP-38 nm decreased compared to the control. Improving nutrients, oil and protein amount in soybean seeds up to 200 mg/kg indicates the potential for using ZnONPs fertilizer for plants grown in zinc-deficient soils to improve seed quality.