Effect of high temperatures on seed germination of Solanum aculeastrum

Solanum aculeastrum is a medicinal plant that showed low seed germination under laboratory conditions. The objective of this study was to establish whether germination could be improved by the exposure of its seeds to high temperatures such as those registered on surface soils during natural fires. Our results indicated that temperatures of 100 and 120°C applied to green mature seeds of S. aculeastrum, for 45 to 60 min may break their innate dormancy, thus stimulating their subsequent germination to more than 85%. Germination in dry seeds, however, showed very low germination when subjected to high temperatures. Where the effect of smoke was tested on the germination of the green mature and dry seeds of S. aculeastrum, no stimulation of germination was observed. The ecological implications of these observations are discussed.