Germination of native forest species planted by direct seeding

Resumo

Direct seeding has increasingly emerged as an alternative and/or complementary technique for ecological restoration. In this sense, several factors have been explored to make the process viable, such as the use of germination protectors, which would increase the temperature and humidity of the seedbed, in addition to protecting the seeds against herbivory. In the present study, the effect of a protector on the germination of seeds of three native forest species was tested. For this purpose, three species were selected (Enterolobium contortisiliquum, Handroanthus impetiginosus, and Sapindus saponaria). Initially, the seeds were evaluated in the laboratory, being subjected to germination conditions in a BOD-type chamber at 25ºC and a 12-hour photoperiod. From these results, two seeding densities per seedbed were defined in the field. Thus, the seeds of each species were tested with and without the germination protector and with two seeding densities, in a 2x2 factorial scheme. The germination protector was effective in increasing the total value and speed of germination of Enterolobium contortisiliquum and Handroanthus impetiginosus seeds. Sapindus saponaria seeds, although not benefiting from the use of the germination protector, germinated well under field conditions. The densities studied, it seems, had little influence on the germination process of the species studied, indicating that excessive densities do not guarantee the formation of individuals. Direct sowing for enrichment purposes proved viable, especially for Enterolobium contortisiliquum and Sapindus saponaria.