The role of mucilage in the germination of Leptocereus scopulophilus (Cactaceae) seeds from Pan de Matanzas, Cuba

Abstract

Studies of seed mucilage in a number of species suggest that it has multiple ecological roles dependent on species and their environmental context. We evaluate whether mucilage facilitates seed germination for Leptocereus scopulophilus Areces, as well as whether light conditions influence the effect of the mucilage. Three combined treatments of light conditions: (1) shade (10% of sunlight), (2) semi-shade (30% of sunlight), and (3) full light exposure (100% of sunlight), and two seed types (with mucilage and washed) were used. Germinability was affected by light conditions but no effect of mucilage was found; higher germination occurred in shade than in semi-shade conditions. There was no germination in full light conditions. Germination rate (T50) was not affected by light conditions or by the mucilage, or the interaction of both factors. Minimal time to germination (Tmin) was affected by mucilage; seeds with mucilage germinated 2 days later than washed seeds. Thus, facilitation for imbibition of water does not occur in L. scopulophilus seeds. Perhaps the presence of mucilage in seeds of this species serves other purposes such as seed adhesion to soil or to deter predators.