Sombreamento na emergência de plântulas e no crescimento inicial de dipteryx alata vog

Abstract

This work was carried out in order to evaluate the potential of germination of the seeds and the seedlings growth of baru (Dipteryx alata) in different levels of shading. To evaluate the emergency, the sowing was realized in trays of cells filled with Plantmax® substratum + land + sand + chicken manure in proportion of (1: 1: 1: 0.5) and kept in the full sun, 50 % and 70 % of shading. The experiment was carried out in design entirely randomized with three levels of shading in four repetitions of 25 seeds. It was evaluated the percentage and the velocity of the emergency index. To evaluate the initial growth, the seedlings were transplanted and, three repetitions of 15 changes totalizing 45 seedlings were kept in its respective shading. The experiment was realized in a complete randomized design in factorial 3 (shading levels) x 5 (times of evaluation for height, diameter of collect, total chlorophyll, transpiration, stomatal conductance and photosynthetic rate) and 2 (times of evaluation for leaf area, length of root, fresh and dry mass). The shading levels did not influence the percentage and the velocity index of seedling emergency (71.3 % and 1.08 respectively). High value of height (16 cm), leaf area (220.2 cm2), length of root (14.9 cm), fresh and dry mass (9.71 g and 3.21 g) of seedlings were observed under shading not varying between them. The seedlings presented lower photosynthetic rate in the 70 % of shading (6.8 μmol m-2 s-1). The levels of shadings did not influence in seedling emergency.