Changes in the germinability of seeds of dicotyledonous herbs from anthropogenic and wild habitats during two initial years in a seedbank

Abstract

The germinability of buried seeds changes with time, and the direction and periodicity of these changes differ among plant species. In 116 abundant dicotyledoneous herb species, we investigated the changes in seed germinability that occurred during the 2-year period following burial in the soil. We aimed to establish differences between seeds collected in “anthropogenic” (ruderal, arable land) and “wild” (grassland, forest) habitats. The seeds were buried in a field one month after collection, exhumed at regular intervals and germinated at 25 °C. During the two-year study period, four categories of species-specific patterns of germinability changes were found: seeds demonstrating seasonal dormancy/non-dormancy cycles (31 species), seeds germinating only in the first season after burial (16 species), seeds germinating steadily (38 species) and seeds whose germinability changed gradually, with increasing (7 species) or decreasing (18 species) germinability. The seeds of 6 species did not germinate at all. We found no significant difference in the frequency of these categories between species typical for anthropogenic and wild habitats. The cause for this result may be dramatic human influences (changes of agricultural practices), the pressure of which impedes the development of floras specific for certain habitats, as distinguished by the frequency of species with particular patterns of seed germinability. These frequencies varied among taxa with the growth form, seed mass and flowering phenology of species.