Sensibilidade de variedades de feijão (Phaseolus vugaris L.) ao alumínio em solução

Abstract

One of the main causes of losses in agricultural productivity is due to the high concentrations of aluminum (Al) in the soil solution, characteristic of acidic weathered soils in the humid tropical zone. Al affects the morphology and physiology of the root system, limiting the deepening of roots in the soil and the absorption of water and nutrients. The aim of this study was to evaluate the effect of different concentrations of Al (0,0; 1,5; 3,0 mg L-¹) on the root development of common bean, Formoso, Alvorada, Harmonia, and Diplomata varieties, by evaluating morphological changes in the roots of the seedlings, visible by optical microscopy, and the rate of root elongation. The experiment was carried out under laboratory conditions, in a completely randomized design, with three replications. The results of root growth rate (mm day-1) were subjected to analysis of variance and compared by the Tukey test (p<0.05). The increase in the concentration of Al in solution caused a decrease in the rate of root elongation (mm day-1) in the four common bean varieties. Seedlings of the Harmonia variety were more tolerant to the presence of Al regarding to root elongation rate. The 4-day period of exposure of roots to Al caused visible morphological damage only in the Formoso variety. The critical concentration of Al in solution, from which there was a decrease in the rate of root elongation, was 1.5 mg L-¹ of Al. Root biometry indicated the following sequence of common bean varieties in terms of tolerance to Al in solution: Harmonia > Formoso = Alvorada = Diplomata.