Bancos de sementes do solo da reserva biologica e estação experimental de Moji Guaçu, em area de cerrado no estado de São Paulo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

In spite of have been initially considered an exceptional condition, sexual reproduction of cerrado plants is now accepted as a common fact, as mentioned by several authors working in field and laboratory conditions. Nevertheless, the composition and dynamics of cerrado soil seed banks remain to be understood. This study intends to investigate the soil seed bank from the Reserva Biológica e Estação Experimental de Moji Guaçu SP, Brazil, using two different methods, seedling emergence and sieving soil. The soil samples were collected random1y in three soil layers (0-5 cm, 5-10 cm and 10-15 cm) in four habitats: marsh, gallery forest, cerrado and open cerrado at two different seasons (summer and winter) along two years. The seedling emergence method indicated the occurrence of a denser seed bank in the marsh than the sieving method. However this was an exception since by the sieving method more seeds were separated in all other environments. Seedling emergence occurred most frequently at the 0-5 cm soillayer and up to the first three weeks of experimentation. The sieving method provided more detailed information about the composition, dynamics, and differences among the habitats analyzed. The season has influenced the results, more seeds were found in the soil at the dry season (winter). For a complete understanding of the seed bank dynamics in the soil, the viability of artificially buried seeds was studied. Seeds of woody and herbaceous species occurring in the Reserva were collected and buried in forest and cerrado soils. The germination tests were performed at 25°C under light and darkness and the results showed dormancy and photoblastism in seeds of Porophy/lum lanceolatum DC and Diplusodon virgatus Pohl, what have favoured the time of permanence in soil for seeds of those species. From the data obtained it can be conc1uded that the superficial layers of soil contain the bulk of the seed bank in the Reserva. This bank is composed mainly by tiny seeds that can germinate easily when submitted to the conditions of light and temperature used in this study. Gallery forest has a more diversified soil seed bank in contrast to cerrado but both of them have more seeds in the dry season

ASSUNTO(S)

cerrados sementes - armazenamento bancos de sementes germinação

ACESSO AO ARTIGO

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