Biometria e germinação de sementes de espécies vegetais nativas de Carajás.

Abstract

The low germination rate, as well as the lack of basic knowledge about seeds of native species, such as size and mass, constitute some of the main bottlenecks of their use with greater success in environmental recovery programs. In this study, it was evaluated the biometry of seeds of native species of FLONA Carajás and the effect of scarification of the seed coat on their germination, aiming at the optimization in the use of seeds of native species in programs of revegetation of mined areas. The pre-germinative treatments of the seeds consisted of topping (mechanical scarification), immersion in sulfuric acid (98%) (chemical scarification) and immersion in hot water (100 ° C) (thermal scarification), tests carried out according to the Rules manual for Seed Analysis (RAS, in portuguese). The results showed that i) the size and mass of the seeds were quite variable between species; ii) all groups of growth habits analyzed presented, on average, germination rates below 60%, in addition to reduced germination speed; iii) after scarification, the seeds of native species germinated, on average, practically 3 times more and presented germination speed approximately 11 times higher; iv) 17 of the 18 leguminous species showed low germination rates, evidencing the existence of some type of dormancy. Seed size and mass vary widely among native species. Mechanical scarification of the seed coat increases the seed germination rate in most of the studied species, being considered the best method.