Dados do Trabalho

Título

SELENIUM BIOFORTIFICATION ENRICHES QUINOA GRAINS AND MITIGATES WATER DEFICIT

Resumo

Selenium plays an essential role in human and animal biological processes. Biofortification reduces the risk of human health disorders by increasing the bioavailability of organic Se in edible plants grown in Se-deficient soils, in addition to improving the defense system of crops to water deficit. These studies aim to enrich quinoa grains with selenium and to elucidate the Se-promoted tolerance mechanism in plants grown under water deficit. Selenium was applied to the soil under irrigation and water deficit conditions at rates of 0, 0.25, 0.5, 0.5, 1.0, and 2.0 mg kg-1 for quinoa var INIA Salcedo in Peru and quinoa cultivar BRS Piabiru in Brazil. Gas exchange, WUE, antioxidant enzyme activity, and hydrogen peroxide concentration in leaves at the end of the water deficit were evaluated. At harvest, dry mass in shoots and grains, Se and macronutrient accumulation, Se recovery, and non-enzymatic activity in grains were quantified. Selenium accumulation by grains increased in relation to Se rates in two soil water conditions for both quinoas. Water deficit reduced gas exchange, disrupting photosynthesis and decreasing grain dry mass; however, Se rates up to 1 mg kg-1 increased gas exchange, grain dry mass, and N, P, and K accumulation. In addition, Se promoted SOD, CAT, and APX enzyme activities and minimized H2O2 concentration in the BRS Piabiru cultivar and free amino acid accumulation in the INIA Salcedo variety. Biofortification improved the nutritional quality of quinoa grains with selenium. Selenium enhanced quinoa defense systems to mitigate oxidative stress under water deficit, mainly increasing antioxidant enzymatic activity for the BRS Piabiru cultivar and non-enzymatic activity for the INIA Salcedo var. Low rates of Se application under water deficit were shown to be the best for regulating gas exchange, allowing the continuity of photosynthesis and the accumulation of biomass and macronutrients.

Palavras-chave

Chenopodium quinoa, Antioxidant enzymatic activity, Antioxidant non-enzymatic activity, Gas
exchange, Tolerance mechanisms, Plants’ defense system

Instituição financiadora

The Brazilian National Council for Scientific and Technological Development (CNPq)

Agradecimentos

Soil Science Department and the Soils, Plants, Waters, and Fertilizers Laboratory (LASPAF) from Universidad Nacional Agraria La Molina (UNALM), La Molina, Lima, Peru and Soil Science Department from Federal University of Lavras (UFLA), Brazil