Germination of seeds from herbaceous plants artificially stored in cerrado soil

The germination of three cerrado herbaceous species: Bidens gardneri, Vernonia herbacea (Asteraceae) and Psychotria barbiflora (Rubiaceae) was studied using seeds stored in cerrado soil and in refrigerator at 4°C. The field experiment was carried out at a preserved area of cerrado, the Reserva Biológica e Estação Experimental de Mogi-Guaçu, State of São Paulo, Brazil. The soil was collected in the same cerrado where the experiment was carried out. The achenes of Bidens gardneri are light sensitive, but this sensitivity disappeared when the achenes were stored in soil. With 3 months storage in cerrado soil no differences in germination in light or darkness were detected. The number of intact achenes retrieved from storage in soil decreased with increasing time of storage. A large number of seeds had already germinated during the 3 months storage in soil. The longevity of seeds of this species stored for nearly 10 years at 4°C was checked: the achenes were viable for a long period of time but less than 10 years. Intact achenes of Vernonia herbacea could be retrieved from the soil only with 1 month storage. Germination was always very low and only 15% of the achenes possessed embryos. The number of intact seeds of Psychotria barbiflora decreased the longer the period of storage in soil. Germination of seeds stored at 4°C or in the soil was always very low. From the germination studies of stored seeds in cerrado it can be concluded that Vernonia herbacea does not form a seed bank and Bidens gardneri and Psychotria barbiflora may form a temporary seed bank in cerrado.