SEED SIZE AND PRE-GERMINATION TREATMENTS ON GERMINATION AND GROWTH OF Ormosia paraensis Ducke

Abstract

Studies diverses have already demonstrated the importance of overcoming dormancy in Ormosia paraensis seeds. However, there are no reports considering the effect of seed size combined with scarification on the germination of Ormosia paraensis. Thus, the objective of the present study was to evaluate the effect of seed size related to mechanical and chemical scarification on the germination and initial growth of Ormosia paraensis seedlings. The treatments were arranged in a completely randomized design, in a 3 x 3 factorial scheme: three seed size classes (small, medium and large) and three scarification methods (mechanical, immersion in 98% sulfuric acid for 15 and 30 minutes, respectively ), with four replications of 25 seeds. Germinated seeds were counted daily until the 20th day and the germination percentage (GP), mean germination time (MGT) and germination speed index (GI) were calculated. For the seedling performance test, 10 germinated seeds from each treatment were transferred to 110 cm³ tubes and kept for 30 days in the nursery. At this stage, the following were evaluated: stem diameter (SD), shoot height (SH), root length (RL), fresh mass of the shoot (FMS) and root (FMR). Data analysis indicates that large mechanically scarified seeds promoted the highest averages in the variables %G, GSI, SD, SH and FMS, except for RL and FMR. The large seed category combined with mechanical scarification promotes greater germination and more vigorous seedlings of Ormosia paraensis.