Effects of Light/Darkness and Inhibitory Components on the Germination of Pinus pinaster

Abstract

As with many other species of pine, the only possibility of regeneration for Pinus pinaster is from seed. The advantage of germination is that it increases the genetic variability and stability of populations. This species has an important natural recovery rate in the field after a wildfire. However, no germination or survival of seedlings under adult trees with a capacity for producing viable seeds has been seen to exist in the field. The hypothesis of this paper is that germination under the cover of the adult trees could be controlled by the following ecological factors: availability of light, inhibition by substances produced by the aboveground mass of the tree or inhibition produced by substances emitted by decomposing fallen litter. The effect of nutrient availability on germination was analysed. The germination percentages were high in all of the treatments carried out, with a positive effect appearing in the germination of leaf exudates and a lower percentage in the seeds left in total darkness. However, no significant differences are observed among the total germination percentages. The main difference between the effects of the different treatments appears in the mean time required to germinate: it was shortest in the seeds treated with leaf exudates and longest in the seeds left in total darkness