Abstract
It has been considered that Mimosa aculeaticarpa var. aculeaticarpa and M. luisana have the potential to restore temperate and semi-arid environments, respectively. Mature seeds were collected from eight mother plants per taxon to determine the effects of scarification and temperature on seed germination of both taxa, and to define the optimum temperature for germination. To obtain a representative sample of each taxon, seeds with the same weight and size were mixed. Five replicates of 20 seeds each (100 seeds per taxon/temperature, plus the control) were established. The seeds were mechanically scarified and incubated under controlled conditions: 5 to 45 °C with 5 °C intervals, and a 12h light/12h darkness photoperiod. Results showed that scarification and temperature were significant factors in seed germination. In both taxa, germination was epigeal and phanerocotylar. The highest seed germination percentages were obtained when seeds were scarified. 88 % of seeds of M. aculeaticarpa var. aculeaticarpa germinated at 25 °C. A hundred percent of seeds of M. luisana germinated at 30 °C. The optimum temperature for germination of seeds of both taxa was established at 25 °C. Mimosa taxa differ in the germination rate: M. luisana germinated at 6.6 seeds/day and M. aculeaticarpa var. aculeaticarpa at 3.4 seeds/day. Overall results suggest that, for both taxa, an increase or decrease in temperature will not inhibit seed germination, supporting the recommendation to use these plants for reforestation, as part of environmental restoration projects in temperate and semi-arid Mexican regions.