Geometric morphometric analysis as a tool to explore covariation between shape and other quantitative leaf traits in European white oaks

Abstract

In this study, 2-Block Partial Least-Squares analysis was used to explore the pattern of covariation between two sets of leaf morphological data (landmarks and traditional measures), sampled on 273 trees in a mixed forest of Quercus frainetto, Q. petraea and Q. pubescens, in southern-central Italy. Two groups of related variables were detected and the three oak species were highly significant discriminated by CVA computed on dimensions extracted by 2B-PLS analysis. Q. frainetto was characterized by obovate leaf blade with a short petiole and leaves were greater than in the other species. Q. petraea was differentiated by acute basal and apical regions, while Q. pubescens has higher values of leaf compactness, pubescence and length of trichomes. The high degree of classification accuracy of this combined approach advocates its extension to other problematic species and highlights its importance as an exploratory tool in plant ecology, physiology and taxonomy.