Seed germination of Opuntia dejecta, a non-desert cactus native to Central America

Opuntia species from arid and semiarid environments have dormant seeds. The objective of this study was to evaluate how the soil influences seed germination of the cactus O. dejecta. We hypothesized that O. dejecta seeds in the basaltic rocky soil will show lower seed germination than seeds in a site with alluvial soil from the coastal plain. An experiment of partial reciprocal transplant was performed, placing seeds from basaltic soil (San Ignacio population) in pots containing alluvial soil from Puente Nacional population and in slabs from basaltic soil, and placing them on two greenhouses, in San Ignacio population and Puente Nacional population. We found that seed germination (%) was lower in San Ignacio site (with basaltic soil) than in Puente Nacional site (with alluvial soil), and that alluvial soil showed higher seed germination than basaltic soil, as well as higher seed germination in Puente Nacional than in San Ignacio. The results suggest that seed dormancy for the population situated in the rocky condition is a trait locally adapted, and the basaltic soil can be considered as a selection factor.