Effect of temperature on the germination of Cistus ladanifer L.

Abstract

In previous laboratory studies involving heat treatments Cistus ladanifer had the highest promotion of germination at 90 ºC, but water uptake by seeds due to seed coat rupture by heat could not account for the observed results. To investigate the hypothesis that increases in soil temperature resulting from the elimination of leaf canopy by previous fires might play a role in C. ladanifer fire-ecology, seeds of this species were incubated at constant and alternate temperatures. Lag and final germination are generally improved in a way consistent with the hypothesis under investigation. However, the stimulating effect is not great enough to account for the values of lag and final germination directly attributable to fire, and other explanations for the stimulus of C. ladanifer germination must be considered and investigated.