Abstract

LESSA, B. França da Trindade et al. Germination and seedling growth of Enterolobium contortisiliquum as a function of seed weight and temperature and light conditions. Agrociencia [online]. 2015, vol.49, n.3, pp.315-327. ISSN 2521-9766.

Studies of germination behavior and seedling establishment contribute to the development of appropriate methods of forest species management. The aim of this study was to investigate germination and seedling growth of tamboril (Enterolobium contorsiliquum (Vell.) Morong), taking into account environmental factors and seed weight. Seeds were separated into three weight classes (light, medium and heavy), to determine the moisture content percentage and thousand-seed weight per class. Seeds from each class were then tested for germination. The experimental design was completely randomized with a 2x3x4 factorial arrangement of treatments: two light conditions (presence and absence), three weight classes (Light < 0.7 g; Medium 0.7 to 0.8 g; Heavy > 0.8 g) and four temperatures (20, 30, 40 and 20-30 °C), with four replications each. Percentage of germination and germination speed index for seed vigor were determined. For the evaluation of seedling growth, the length and dry mass of both the shoot and root were determined. When the data proved normal, ANOVA and Tukey tests (p≤0.05) were conducted to compare treatment means. Non-normal data were analyzed using nonparametric Mann-Whitney test (p≤0.05). Germination speed index, shoot dry mass and root dry mass data presented a normal distribution, allowing for ANOVA testing. Germination occurred regardless of light conditions, with a higher speed at 40 °C, although this temperature was detrimental to seedling growth. The temperature of 30 °C promoted better germination (>80 %) and seedling growth. Heavy seeds displayed improved germination and produced more vigorous seedlings.

Keywords : Environmental factors; tree species; tamboril; seedling vigor.