Dispersal of seeds by animals: effect on light controlled dormancy in Cecropia obtusifolia

Abstract

This paper deals with the effect of the passage of seeds through the intestines of animals on the properties of the light-controlled germination of the tropical pioneer species Cecropia obtusifolia. The seeds used in the experiments came from the feces of three species of mammals, the soil seed bank, a group of buried seeds, and directly from the infructescence. The experiments involved exposing seeds to particular light conditions, including simulated gaps of different sizes in the field and laboratory and to different red/far red light regimes in growth chambers. We also measured spectral transmittance of the seed coats. Seeds with different histories differed in light sensitivity and transmittance. Passage through two species of mammals reduced the effectiveness with which far red exposure counteracted the effects of previous red exposure. As a result the seeds became polymorphic in their responses to light.