Geographical uncoupling between leaves and flowers in Embothrium coccineum, a south-Andean Proteaceae.

CHALCOFF, V., EZCURRA, C. Y AIZEN, M.

ANNALS OF BOTANY

Oxford Journals

Lugar: Oxford; Año: 2008 vol. 102 p. 79 - 91

0305-7364

Background and Aims Geographical variation in foliar and floral traits and their degree of coupling can providerelevant information on the relative importance of abiotic, biotic and even neutral factors acting at geographicalscales as generators of evolutionary novelty. Geographical variation was studied in leaves and flowers ofEmbothrium coccineum, a species that grows along abrupt environmental gradients and exhibits contrasting pollinatorassemblages in the southern Andes.Methods Five foliar and eight floral morphological characters were considered from 32 populations, and their patternsof variation and covariation were analysed within and among populations, together with their relationship withenvironmental variables, using both univariate and multivariate methods. The relationships between foliar and floralmorphological variation and geographical distance between populations were compared with Mantel permutationtests.Key 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 associatedwith 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. Thisstudy supports the view that character divergence at a geographical scale can be moulded by different factorsacting in an independent fashion.