Pré-tratamento de sacarose induzindo tolerância à hipoxia e ao excesso de manganês

Abstract

We investigated the effects off pre-treatment with sucrose in promoting the tolerance of soybean plants to excess Mn and hypoxia. Thus, soybean plants in stage V5 were submitted to treatments (i) control, (ii) Mn excess, (iii) pre -treatment with sucrose + Mn excess, (iv) hypoxia + excess Mn, (v) pre - treatment with sucrose + hypoxia + excess of Mn, for 15 days. The concentration of Mn, Cu, Fe and Zn, visual symptoms, biomass accumulation, photosynthetic pigment concentration, gas exchange, sucrose, starch and amino acid content, enzymatic and non-enzymatic antioxidant system besides the quantification of reactive oxygen species and lipid peroxidation. The excess of Mn caused reduction of the accumulation of biomass, pigments, gas exchanges and a greater oxidative damage. However, pre-treatment with sucrose led to higher plant performance. As plants that were submitted to hypoxia and to excess of Mn were the ones that stood out the most, with greater accumulation of biomass, pigments, gas exchanges and better performance of the defense mechanisms like greater biosynthesis of nonenzymatic antioxidants. Thus indicating that pre-treatment with sucrose may be a promising alternative for the induction of soybean tolerance to excess Mn and hypoxia.