Seed germination of Magnolia pugana (Magnoliaceae), an endemic and endangered species from Western Mexico

Magnolia pugana is an endemic and endangered species located in western Mexico, which is distributed in gallery forests in the canyons of southern Zacatecas and north-central Jalisco. The aim of this study was to determine the seed viability and to identify the treatments to break seed dormancy in M. pugana. Seeds were collected from four locations, three of them located in Jalisco (Centro Universitario de Ciencias Biologicas y Agropecuarias, San Lorenzo and San Nicolas) and one in Zacatecas (Palo Verde). The following germinative treatments were applied: (1) manual aril removal, (2) aril removal by leaching, soaking in gibberellic acid at different concentrations: (3) 100 mg L-1, (4) 200 mg L-1, (5) 300 mg L-1, and (6) control. One hundred seeds were used per treatment with five replicates each. The treatment with the highest germination percentage for all four sites was the manual aril removal with 52 %, whereas the treatment with the lowest germination was the control with 3.5 %. By location San Lorenzo had the highest germination percentage at 16.5 %, while San Nicolas had the lowest percentage (5.33 %). Germination treatments failed to break dormancy (germination rates < 70 %). The seeds of the four locations imbibed water so no physical seed dormancy occurs. Seeds with higher biomass did absorb less water.