Seed germination of Bromelia serra (Bromeliaceae): effects of the canopy openness where the mother plant lived and the light environment of the germination place.

Context: Some plant species show within-generational and trans-generational phenotypic plasticity associated with the light environment for germination traits. In bromeliads, light affects the seed germination of several species, but there is no study analysing the effects of the light environment where the mother plant lived on seed germination. Bromelia serra inhabits the understorey of xerophytic forests, where individuals could be conditioned by the heterogeneous light environment because its cover and abundance are negatively associated with tree basal area and woody vegetation cover. Aims: To analyse the effect of the light environment on seed germination of B. serra , considering also the light environment where the mother plant lived. Methods: In four patches from three different sites in a stand of a Schinopsis balansae forest, 48 fruiting plants of B. serra were harvested. Canopy openness was obtained from a hemispherical photograph taken above each plant. From each infructescence, half of the seeds from five fruit were kept in light conditions and the remaining seeds in dark conditions in a germination room. Key results: There was no effect of the light environment where mother plants lived on seed germination, but the light environment in the germination room positively affected germination variables. Conclusions: The positive effect of light on seed germination of B. serra might explain the spatial distribution of individual plants in these xerophytic forests. Implications: These results have enhanced our understanding of the regeneration and distribution of understorey herbaceous species in these South American forests. Seed germination may be controlled by the light environment where seeds germinate and by that experienced by the mother plants. In a germination experiment of a terrestrial bromeliad from xerophytic forests, we found that the light environment where mother plants lived did not affect seed germination, but seeds exposed to light conditions showed a higher germination rate than those in the dark. These results enhance our understanding of the regeneration and distribution of understorey species in these South American forests. [ABSTRACT FROM AUTHOR]