ZnO nanoparticles and nitric oxide donor molecules in rice cultivation: evaluation of the synergistic effect in mitigating toxic elements and biofortification with Zn

• Grant number: 20/00392-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: June 01, 2022
• End date: June 30, 2022
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Bruno Lemos Batista
• Grantee: Rodrigo Mendes Pereira
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Santo André , SP, Brazil

Abstract

The high demand for foods widely consumed worldwide, such as rice, has increased the search for strategies to increase the productivity of this type of crop. However, there is also significant concern regarding the production of nutrient-dense foods and with negligible contaminants concentrations. Several technologies have been developed and applied in agriculture to increase crop productivity and resistance to pests and abiotic factors. Nevertheless, few technologies enable the mitigation of toxic elements from cultivation (soil, water, air, etc.) and biofortification with essential elements simultaneously. In this sense, the use of nanoparticles (NPs) containing essential elements, such as Zn, should be highlighted because of the promising results that have been presented in recent years. However, few studies are evaluating the application effects of these NPs in the mitigation of toxic elements. Moreover, some studies have shown that is necessary to apply higher concentrations of these products during plant development for biofortification, which ends up resulting in phytotoxic effects. On the other hand, the application of exogenous nitric oxide (NO) on plant growth has been shown to be a promising strategy for the reduction of oxidative stress caused by high concentrations of metals. It is important to note that, although there is evidence that both technologies (metallic NPs and exogenous NO) have the potential for application in agriculture, no studies are demonstrating the application of nanoparticles containing essential elements and NO donor groups in rice cultivation. Thus, this project aims to synthesize and characterize ZnO NPs and to evaluate its application, in the presence and absence of NO donors (S-nitrosoglutathione - GSNO), in rice cultivation aiming at the mitigation of toxic elements (such as As, Cd and Pb), the biofortification of rice grains with Zn and the increase in productivity. For this, it is intended to adapt literature synthesis methods and to characterize the products by well-established techniques. The experiments with rice will take place in three stages and the ZnO NPs + GSNO will be applied directly to the leaves (foliar spray application). A treatment with ZnSO4 (Zn in ionic form) will also be evaluated for comparison. In the first stage, rice cultivation will be carried out in pots, inside a greenhouse, from seed germination until the end of the vegetative phase as a preliminary way of evaluating the treatments with ZnSO4 or ZnO NPs, in the presence and absence of GSNO. In the second stage, rice cultivation will also be carried out in pots and inside a greenhouse, but the experiment will be conducted from seed germination until the end of the reproductive phase. In both stages, several treatments with varying concentrations of ZnSO4 or ZnO NPs will be evaluated and, at the end of second stage, the treatment that provides the best results associated with As, Cd and Pb mitigation, biofortification with Zn and plant development (evaluated through morphological, physiological and biochemical variables) will be selected. In the third step, a field experiment will be conducted to confirm the effectiveness of the selected treatment and to evaluate its effects on As, Cd and Pb mitigation and Zn biofortification, as well as its influence on grain productivity. Besides, it is intended to establish an analytical method that enables the ZnO nanoparticles dimensioning in rice since the techniques commonly used for this purpose have limitations for the analysis of vegetal matrices. (AU)