Asexual regeneration and its implications for local bryophyte establishment in a Brazilian tropical rain forest

Abstract

Bryophyte spores commonly show ready germination under laboratory conditions and are assumed to be responsible for long-distance dispersal, but their role in plant establishment under field conditions is considered less important overall than asexual vegetative propagation. Local establishment from spores or vegetative propagules have not been extensively examined among tropical bryophyte species, making it difficult to test hypotheses concerning their roles under natural conditions. I examined 11 bryophyte species from two sites in a tropical rain forest in Brazil to investigate the regenerative capacities of detached leaves (vegetative propagules) under laboratory and field conditions. Spore germination and early gametophyte development were also analyzed for the most prolific spore-producing species. Detached leaves, in contrast to spores, promoted the most rapid plant local establishment, and performed similarly under both culture conditions. Most prolific spore-producing species did not necessarily demonstrate the lowest leaf-regeneration rates. Roles of detached leaves in the persistence strategies of bryophyte species from the Brazilian Atlantic rain forest (especially the dioecious mosses Leucoloma serrulatum Brid., Leucobryum clavatum Hampe, and Pyrrhobryum spiniforme (Hedw.) Mitt.) are reported for the first time, and information concerning the production and germination of spores under field conditions likewise contributes to our understanding of the roles of spores in bryophyte establishment.