Patterns made of patterns:: variation and covariation of leaf nutrient concentrations within and between populations of Prunus mahaleb

Patterns of within and between population variation in concentrations of nutrients (N, P, K, Ca, Na, Mg, Cu, Fe, Mn, Zn) are reported in mature leaves of individual Prunus mahaleb (Rosaceae) trees from five south-eastern Spanish populations. MANOVA and canonical discriminant analysis were used to identify the contribution of individual nutrients in explaining differences between populations in average nutrient composition. Common principal components analysis was used to test whether the structure of covariation between leaf macronutrients was maintained at different populations. Populations differed in average nutrient composition and were separated mostly by variation along an axis defined by Ca on the positive side, and Mg on the negative one. The sign and magnitude of the correlations between individual nutrients varied between populations. Multivariate patterns of nutrient covariation differed between populations, the variation being unrelated to population differences in mean nutrient composition. Results suggest that, at the regional scale, phenotypic integration of the foliage concentrations of different nutrients was weak, and highlights the importance of studying nutrient covariation structures. (C) New Phytologist (2001).