Aspectos ecofisiológicos da germinação de sementes de Colubrina glandulosa Perkins

Abstract

The increasing anthropogenic impacts have been causing many environmental consequences, such as the degradation of forest environments. Therefore, it is necessary to realize research that collaborates to the development of instruments to support the recovery of these areas. In this sense, Colubrina glandulosa Perkins (Rhamnaceae), popularly known as sobrasil and saraguaji, may be helpfull because of its ability to grow quickly and tolerate different environmental conditions, and so might contribute to the conservation and recovery of degraded areas. Thus, the aim of this research was to determine a methodology as well as ideal environmental conditions of germination and vigor of C. glandulosa through the biometrical characterization, dormancy-breaking, effects of temperature, substrate, light quality and sowing depth, aiming to contribute to the conservation and management of this species. To reach the objectives of the work, fruits of two matrices located in Carpina, PE were picked. Initially, the water content of seeds was determined by the oven method at 105ºC for 24 hours. The biometric characterization was performed using a digital caliper with a precision of 0.01 mm in which the length, width and thickness of 100 randomly selected seeds were measured. For the dormancy and temperature experiment, seeds were immersed in concentrated sulfuric acid for a period of 30, 60, 90, 120 and 150 minutes and placed to germinate under continuous light at temperatures of 20-30°C, 25°C and 30°C. To evaluate the effect of substrate were used sand, vermiculite, tropestrate, coconut powder, blotting paper and paper towel, the last one organized in rolls. The sowing depth was performed using styrofoam trays in which the seeds were sown in depths 0; 0.5; 1.0; 1.5 and 2.0 cm. Regarding the light quality, the seeds were submitted to four regimes of luminosity: white, red, red-extreme and absence of light. The results showed that the seeds of Colubrina glandulosa have low variability of the biometric aspects. Temperatures of 20-30°C and 30°C may be used to conduct experiments of this specie. The effectiveness of the chemical scarification method with sulfuric acid was demonstrated to overcome the dormancy of the specie, for 120 and 150 minutes. The substrates sand and vermiculite are the most suitable for experiments with Colubrina glandulosa. The seeding can be realized at depths between 0.5 and 2.0 cm. The specie demonstrated emergency capacity in all treatments used for light quality, evidencing that it has the potential to establish in environments with different luminosities. Thus, Colubrina glandulosa demonstrated the potential to be used in projects and programs for the restoration of degraded environments and urban afforestation, contributing to the conservation and preservation not only of the specie, but also of the forest environments.