Densidade, germinação e flora do banco de sementes no solo, no final da estação seca, em uma área de caatinga, Quixadá, CE

Abstract

This study investigated density, germinability and floristic composition of the soil seed bank in an area of caatinga (thorny deciduous woodland). Random soil samples were collected in a single sampling at Fazenda Não Me Deixes, Quixadá, CE, from litter (n=100), 0-5cm depth layer (n=100) and 5-10cm layer (n=80). The seedling emergence method was used to determine density and germination curve. The floristic composition was determined using seedling morphology. The total density of the bank was 807 seeds.m-2 and specific densities were 352 seeds.m-2 (litter), 304 seeds.m-2 (0-5cm) and 108 seeds.m-2 (5-10cm). Most of the seeds germinated between the first and fourth weeks: 91% (n=1278; litter), 88% (n=1061; 0-5cm depth) and 89% (n=307; 5-10 depth), but some seeds germinated for up to 14th week. We determined 40 different morphospecies. The germination of about 88% of the seeds between the first and fourth week suggests that most caatinga seeds germinate at the onset of the favorable season, probably losing dormancy, if it exits, during the dry season.