INFLUENCE OF Al³⁺ IN NUTRIENT SOLUTION ON GROWTH OF THREE FOREST SPECIES USED IN RECOVERY OF DEGRADED AREAS

ABSTRACT

One of the main limiting factors in the performance of agricultural and forest crops in tropical soils is the toxic effect of Al³⁺ in soils. However, some plant species present adaptive mechanisms that confer tolerance to these conditions. The aim of this study was to evaluate the development of three tree species grown in nutrient solution with different levels of Al³⁺. Therefore, seedlings of Acacia mangium, Mimosa artemisiana and Enterolobium contortisiliquum were produced in nutrient solution with four concentrations of Al³⁺ (control, 185, 370 and 555 μmol L^-1) during 95 days of cultivation. At the end of the experiment, the plants were targeted and a fraction of the known roots was scanned to estimate root area and length. The stem, leaves and remaining roots were dried in a forced air oven, being determined the biomass and N, P and K in plant tissue. The species showed different patterns of growth due to the increase of the activity of Al³⁺ in nutrient solution, and Acacia mangium and Enterolobium contortisiliquum were more tolerant to Al³⁺, demonstrating potential use in the recovery of degraded areas with acid soils. The N concentration in the plant parts were not influenced by Al³⁺, however the concentration of P increased in the roots of three species with intermediate levels of Al³⁺, resulting in reduction of P in shoots of Acacia mangium and Mimosa artemisiana. The concentration of K⁺ in Acacia mangium was reduced only in the lower Al³⁺, whereas for Mimosa artemisiana was gradually reduced.

Keywords:
Forest nutrition; Mimosa artemisiana; Enterolobium contortisiliquum; Acacia mangium