Análise fisiológica, nutricional e de expressão gênica em cultivares de aveia-branca submetidas ao excesso de ferro

Abstract

White oat (Avena sativa L.) is an alternative for succession of crops with potential for use in irrigated rice (Oryza sativa L.) production areas, in southern Brazil. The characteristics of these soils may limit the growth and development of white oats. Thus, the objectives of this study were to identify an iron concentration capable of causing toxicity in oat plants, besides differentiating sensitive and tolerant genotypes to iron excess, to quantify nutritional contents and to verify possible genes involved in these processes, in order to assist in futures work in the area, as well as indicate cultivars adapted to the growing conditions of southern Brazil. For that, studies were carried out between 2014 and 2016, in a greenhouse and laboratories of the Department of Botany of the Federal University of Pelotas and Crop Soil and Environmental Sciences Departament of the University of Arkansas. The results showed that the concentration of 13.5 mmol L-1 of ferrous EDTA in nutrient solution is efficient for the distinction of oat genotypes submitted to iron excess. The URS Taura genotype is tolerant to iron excess, while the UPFPS Farroupilha and URS Corona are sensitive under controlled conditions through the hydroponic system and should be avoided in areas susceptible to nutrient toxicity. Iron excess alters the nutritional concentration of the other elements in oat plants. Iron excess in the nutrient solution provides significant alteration in the relative expression of some genes related to iron uptake, translocation and storage in oat plants, being that the genes OsGS1, OsFER1 and OsPSBA, seem to be related to the tolerance processes of the cultivar URS Taura to the excess of Fe. The hydroponic system is efficient for the differentiation of sensitive or tolerant cultivars of iron excess, thus making possible more efficient choices for new work and indication of tolerant cultivars to nutrient excess.