Influence of water on the germination of Paricá Seeds (Schizolobium parahyba var. amazonicum Huber ex Ducke)

Abstract

Paricá (Schizolobium parahyba var. amazonicum) is a pioneer forest species, with economic potential, widely used by the timber sector. The seeds of the species have tegumentary dormancy, which can be an obstacle to the production of seedlings on a large scale. The objective was to evaluate the germination of Paricá seeds as a function of different volumes of water added to the substrate to conduct a germination test. The seeds were submitted to the manual topping process to break dormancy and then placed in a germination chamber, in the topping position on the opposite side of the embryo, under a constant temperature of 30ºC and a 12-hour photoperiod, to conduct the germination test for 30 days. A moistened Germitest type paper was used as substrate, with amounts (mL.g^-1 paper) of water equivalent to 2,0; 2,5; 3,0 and 3,5 times the substrate mass, without further addition of water. Subsequently, the germination percentage (GM), the germination speed index (IVG) and the mean germination time (TMG) were evaluated. The experimental design was completely randomized. It was verified that the highest values ​​of GM and IVG were obtained in the treatment with a volume of water equivalent to 2,5 times the mass of the paper. The TMG was obtained more precociously in the treatments with amounts of water 2,0; 2,5 and 3,0 times the mass of the paper. Therefore, it is recommended to conduct germination tests with seeds of the species adopting the water content equivalent to 2,5 times the weight of the substrate.