Effect of high temperatures on seed germination of Prosopis caldenia Burk

Fire may be used to reduce the abundance of woody species in the semi-arid rangelands. However, some evidences indicate that fire can stimulate seed germination of several woody species. Prosopis caldenia is one of the dominant woody species in the semi-arid region of central Argentina. The objectives of this study were to evaluate germination percentage of P. caldenia seeds exposed to high temperatures during different exposure times in the laboratory and to controlled fires under field conditions. Our results indicate that high temperatures (50°C, 100°C and 200°C) applied for a few minutes on free seeds (5 min), pod segments and entire fruits (10 min) of P. caldenia may break their innate dormancy allowing their subsequent germination. The germination percentage of free seeds exposed to controlled fire was slightly higher than that of free seeds not exposed to controlled fire.