Techniques for overcoming dormancy in guanandi seeds

Abstract

The objective of this work was to evaluate different types of preparation of guanandi (Calophyllum brasiliense) seeds, in order to overcome physical and mechanical dormancy, and to verify the effects of temperature and substrate on germination. Three substrates (paper, sand, and vermiculite), two germination temperatures (25 and 30ºC), and four seed preparation types were evaluated: whole seeds; bare seeds, without testa and endocarp; seeds with punctured endocarp in the region near the embryonic axis or in the region opposite of the embryonic axis; and seeds cut at 1/3 of the region opposite of the embryonic axis. Vigor tests were performed (index of germination speed and emergence of seedlings in the field), and the imbibition curve was obtained for the different types of seed preparation. Total wrap (endocarp and testa) withdrawal is necessary to completely overcome physical and mechanical dormancy of guanandi seeds. Seed germination should be held in paper substrate at a temperature of 30°C.