Padrões de absorção de água em sementes de espécies arbóreas nativas da Caatinga

Abstract

Seed germination plays an important role in plant development, starting by water uptake and resulting in the emergence of the embryo from the seed coat. This work investigated water uptake patterns during germination in different woody species from the Caatinga, considering seed size and dormancy. Among eight species were selected, four produce dormant seeds and four exhibit quiescent seeds. The measurement of seed dimensions was carried out to determine seed size. To determine water uptake curves, seeds were sown in paper rolls humidified with distilled water and maintained under controlled conditions until germination. It was observed that species presenting different sizes exhibited distinct pattens of water uptake. Thick seeds like Amburana cearensis and Ceiba glaziovii demonstrated slow water uptake while small seeds as Anadenanthera colubrina and Cenostigma microphyllum revealed fast hydration. It was not possible to clearly relate the presence or absence of dormancy and the patten of water uptake during germination, since the studied species unveiled diverse patterns, like Erythrina velutina and Mimosa caesalpiniifolia, which presented staggered water uptake.