Germination characteristics of Syngonanthus seeds (Eriocaulaceae) in campos rupestres vegetation in south-eastern Brazil

The present study evaluated the size and germination characteristics of seeds of seven species of Syngonanthus (distributed among four sections) that occur in different microhabitats in campos rupestres vegetation in Minas Gerais State, to determine if (1) the germination responses of the various species characterize a single germination pattern for the genus; and (2) there is a correlation between the germination characteristics and the geographic distribution as well as the microhabitat of the different species. The experiments were undertaken with recently collected seeds exposed to a 12-h photoperiod and continuous darkness, at constant temperatures of 10-40 degrees C (at intervals of 5 degrees C) in germination chambers. The results indicated the existence of a pattern of reduced seed size and light requirements for germination within the genus. The geographic distribution of different species of the genus cannot be explained by the responses of seed germination to different temperatures, but suggests some relationship to their edaphic microhabitats. Therefore, germination characteristics of the populations studied may have been selected to colonize specific environments at different soil water conditions.