Influência de diferentes substratos na germinação de sementes da especie Ochroma pyramidale (Cav. ex Lam) Urban

Abstract

The demand for wood in the world grows with the passing of the years, being necessary the increase of the plantations beyond the search of new species that can meet the present commercial necessities, without compromising the needs of the future generations. The species under study has great potential for brazilian silviculture because it is a fast growing species, and currently its wood has great acceptance in the international market. Therefore the objective of this work was to evaluate the most suitable substrate for seed germination of Ochroma pyramidale (Cav. Ex Lam.) Urban. in a nursery under 50% sombrite protection. The experiment was conducted in a completely randomized design with three treatments (substrates) and four replicates of 25 seeds, totaling 100 seeds per treatment and 300 in total. The following substrates were tested: T1 sand, T2 vermiculite and T3 vegetal soil. The effect of the substrates was evaluated by the percentage of germination of seeds (G%), mean germination time (TMG) and rate of emergence (IVE) in addition to the biometric variables of height, leaf number and collection diameter. There was no significant difference in the germination percentage among the analyzed treatments. Vegetable soil presented higher IVE statistically differing from sand and vermiculite, for TMG there was no significant difference between treatments. As for the biometric variables of the seedlings, the seeds conditioned in vegetal land and vermiculite gave rise to seedlings with higher average for the variables height and number of leaves, but only the vegetal land differed statistically from the sand in the leaf number. In the evaluation of the collecting diameter, although the soil presented higher average than the other substrates, there was no significant difference by the Tukey test at 5% probability between the means. All substrates were effective for seed germination of the species, however, when the seeds were conditioned on vegetable soil, they presented higher IVE and the highest averages of all biometric variables analyzed. All substrates analyzed were effective for germination of the species. However under the conditions established in this experiment, the soil substrate was the most suitable for germination of the species.