Uncoupled geographical variation between leaves and flowers in a South-Andean Proteaceae.
OBJECTIVE
Geographical variation in foliar and floral traits and their degree of coupling can provide relevant information on the relative importance of abiotic, biotic and even neutral factors acting at geographical scales as generators of evolutionary novelty. Geographical variation was studied in leaves and flowers of Embothrium coccineum, a species that grows along abrupt environmental gradients and exhibits contrasting pollinator assemblages in the southern Andes.


METHODS
Five foliar and eight floral morphological characters were considered from 32 populations, and their patterns of variation and covariation were analysed within and among populations, together with their relationship with environmental variables, using both univariate and multivariate methods. The relationships between foliar and floral morphological variation and geographical distance between populations were compared with Mantel permutation tests.


RESULTS
Leaf and flower traits were clearly uncoupled within populations and weakly associated among populations. Whereas geographical variation in foliar traits was mostly related to differences in precipitation associated with geographical longitude, variation in floral traits was not.


CONCLUSIONS
These patterns suggest that leaves and flowers responded to different evolutionary forces, environmental (i.e. rainfall) in the case of leaves, and biotic (i.e. pollinators) or genetic drift in the case of flowers. This study supports the view that character divergence at a geographical scale can be moulded by different factors acting in an independent fashion.
Chalcoff
Vanina R
VR
Laboratorio Ecotono, Centro Regional Universitario Bariloche, Universidad Nacional del Comahue, Quintral 1250, 8400 Bariloche, Río Negro, Argentina. vchalcoff@gmail.com
Ezcurra
Cecilia
C
Aizen
Marcelo A
MA
D035264:Flowers / Q000033:anatomy & histology / Q000254:growth & development*; D005843:Geography; D018515:Plant Leaves / Q000033:anatomy & histology / Q000254:growth & development*; D039105:Proteaceae / Q000033:anatomy & histology / Q000254:growth & development*; D013020:South America