Treatments to stimulate and homogenize germination in seeds of Gmelina arborea Roxb.

Two independent trials were established to increase germination capacity of Gmelina arborea seeds. In the first trial, the effect of seed size (small, medium, and large) and two periods of seed imbibition (1 and 6 days) on seed germination were evaluated. In the second trial, several pre-germination treatments (imbibition in different water solutions during a 12-hours period, were also evaluated. In both trials, seeds were placed in a germination chamber at 30 °C during a 30-day period. Analysis of variance showed that the imbibition period did not affect (P<0.05) the rate and percentage of seed germination; however, seed size had a significant effect (P<0.05) on these variables. Large seeds had higher rate and percentage of seed germination than the two other seed sizes. In the second trial, pre-germination treatments did not affect the rate and percentage of seed germination, but they had a significant effect on the rate and total amount of seedlings emerged. Pre-germination treatments also affected the number of plants per seed, the time required to start germination (T10), and germination vigor (T50). Use of a solution with 3 % hidrogen peroxide accelerated seed germination and increased germination vigor of seed.