Testes de envelhecimento acelerado e de condutividade elétrica em sementes de Dictyoloma vendellianum A. Juss.

Abstract

Dictyoloma vandellianum A. Juss., is a tree belonging to the Rutaceae family with a great potential for forestry and ornamental purposes. This work aimed to establish conditions for accelerated aging and the electrical conductivity tests for D. vandellianum seeds. For accelerated aging test, samples containing about 200 seeds were arranged in a single layer on aluminum canvas, in plastic pots containing 40 mL of distilled water at 42 and 45 °C for 0, 12, 24, 48, 72, 96 and 120 h. After these periods, the water content of seeds was determined, at 105 ± 3 °C/24 h, and the germination test was performed at 25-35 °C, on paper and a photoperiod of 8 h. In the electrical conductivity test, the pattern of exudates leaching was evaluated at different periods of imbibition (2, 4, 6, 12, 18, 24, 36, 48, 72, 96 and 120 h), at three numbers of seeds per replicate (25, 50 and 75) and three volumes of deionized water (50, 75 and 100 mL) at 25 °C. The accelerated aging test conducted at 45 °C provided a progressive decrease in the germination with the increase of the aging period. For the electrical conductivity test, lower values were observed with an increasing seed number and the imbibition volume, and higher values with the increase of the periods of imbibition. Therefore the accelerated aging test conducted at 45 °C for 72 h, and the electrical conductivity test performed with 25 seeds imbibed in 50 mL of deionized water for at least 48 h at 25 °C, are adequate to evaluate the physiological quality of D. vandellianum seeds.