Germination of Denmoza rhodacantha (Salm-Dyck) Britton & Rose (Cactaceae)

The germination response of Denmoza rhodacantha (Salm-Dyck) Britton & Rose to seed scarification and different calcium concentrations was analysed. Both scarified and unscarified seeds were treated with two different calcium concentrations (1.74 or 6.36 meq l−1 calcium sulfate in distilled water). All treatments were conducted under a constant temperature (30 °C), and a photoperiodic regime of 12 h light and 12 h dark. Germination was initiated significantly sooner (3.6 days), and the rate of final germination was significantly higher (90.8%), for scarified seeds treated with a solution of 6.36 meq l−1 Ca compared with all other treatments (9.0-11.4 days and 3.6-6.8%, respectively). There were no significant differences among the treatments for the time in which 50% of final germination occurred (6.9-13.6 days). The results suggest that both factors, scarification and calcium concentration, favor germination of Denmoza seeds.