Effects of priming on germination of Buddleja cordata ssp. cordata (Loganiaceae) seeds and possible ecological significance

In order to improve seed germination and establishment of wild trees for restoration and reforestation, the effects of priming on seeds from two populations of Buddleja cordata were studied. Seeds were hydroprimed or osmoprimed with polyethylene glycol (-0.3 MPa) in a 12 h daily photoperiod at 12°C for 0, 1, 2, 4, 5, or 6 days. Priming treatments reduced germination percentages of seeds incubated in light at 25°C and decreased mean germination time. Rates and synchrony of germination were highest in hydroprimed seeds from Ajusco and in osmoprimed seeds from Pedregal. Primed seeds from the least water-stressed site (Ajusco) germinated to higher percentages than those from the most water-stressed site (Pedregal). Further, osmoprimed seeds from both populations germinated to higher percentages than hydroprimed seeds. Increased synchrony and germination rate were retained in osmoprimed seeds (hydropriming not tested) from both populations when stored dry. Germination percentages of primed seeds decreased and increased during storage, but after 78 wk they were not significantly different from those of recently collected seeds. Nonprimed seeds from Ajusco also showed fluctuation in dormancy, but nonprimed seeds from Pedregal had reduced germination through time. The significance of using primed seeds of B. cordata for restoring disturbed lands is discussed.