Transitions between the Terrestrial and Epiphytic Habit Drove the Evolution of Seed-Aerodynamic Traits in Orchids.
Am Nat
; 195(2): 275-283, 2020 02.
Article
en En
| MEDLINE
| ID: mdl-32017633
ABSTRACT
Orchids are globally distributed, a feature often attributed to their tiny dustlike seeds. They were ancestrally terrestrial but in the Eocene expanded into tree canopies, with some lineages later returning to the ground, providing an evolutionarily replicated system. Because seeds are released closer to the ground in terrestrial species than in epiphytic ones, seed traits in terrestrials may have been under selective pressure to increase seed dispersal efficiency. In this study, we test the expectations that seed airspace-a trait known to increase seed flotation time in the air-is (i) larger in terrestrial lineages and (ii) has increased following secondary returns to a terrestrial habit. We quantified and scored 20 seed traits in 121 species and carried out phylogenetically informed analyses. Results strongly support both expectations, suggesting that aerodynamic traits even in dust seeds are under selection to increase dispersal ability, following shifts in average release heights correlated with changes in habit.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Semillas
/
Orchidaceae
/
Dispersión de Semillas
Idioma:
En
Revista:
Am Nat
Año:
2020
Tipo del documento:
Article