Selenium as a mitigation of iron deficiency in soybeans

• Ano de defesa: 2024
• Autor(a) principal: Lapaz, Allan de Marcos
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Soja -Crescimento; Antioxidantes; Micronutrientes; Fotossintese; Soja - Metabolismo; Selênio; Soja - Efeito do ferro; Fisiologia Vegetal
• Link de acesso: https://locus.ufv.br/handle/123456789/32452; https://doi.org/10.47328/ufvbbt.2024.272

Although iron (Fe) is abundant in most agricultural soils, its bioavailability to plants is limited. The Fe deficiency can cause significant changes in plant metabolites, impacting the plant's life cycle. In this context, selenium (Se) has been shown promising effects against Fe deficiency. However, little is known about the role of selenium (Se) in modulating the nutritional status and the non-enzymatic and enzymatic antioxidant defense system in Fe-deficient soybean. In the first experiment, we evaluated the possible beneficial effect of Se applied in the nutrient solution on photosynthetic pigments, nutritional status, reactive oxygen species accumulation, ascorbate and glutathione metabolites, activity of enzymes involved in the synthesis pathway of these metabolites, and antioxidant defense enzymes, including expression of superoxide dismutase (SOD) isoforms, after exposure to absence, deficiency, and sufficiency of Fe in combination with absence and presence of Se. The higher remobilization of Fe associated with maintenance of foliar N concentration resulted in mitigation of leaf chlorosis and decreased loss of photosynthetic pigments in the absence of Fe with Se. Additionally, under this cultivation condition, the main positive effect of Se was shown to be associated with the modulation of the glutathione cycle. The Se supply also reduced the need to replace SOD-Fe with SOD-Cu due to the positive modulation in the crosstalk between Fe and Cu, as well as attenuated the nutritional imbalance of Zn and Mn, mainly in the absence of Fe. These adjustments prevented lipid peroxidation in plants treated with Se. In the second experiment, we evaluated the effects of Se on dry mass, Fe concentration in the roots and shoots, as well as to assess the photosynthetic performance and primary metabolism in soybean plants subjected to Fe deficiency. In the absence of Fe, plants treated with Se exhibited positive modulation in net CO 2 assimilation rate, improving carboxylation efficiency and photochemical traits compared to plants without Se. The synergistic absence of Se and Fe compromised shoot and root dry mass and protein concentration. Therefore, these findings highlight the potential of Se as a valuable intervention to mitigate Fe deficiency in soybean crops. Keywords: Growth. Antioxidants. Micronutrients. Photosynthesis. Metabolism. Selenium. Iron effect.