Fractal dimension does not adequately describe the complexity of leaf margin in seedlings of Quercus species

[摘要] We quantified the complexity of leaf margin in a set ofQuercustree species using fractal dimension estimated by the box-counting method (FDb). Leaves were sampled from seedlings in a set of 15Quercusspecies with a wide range of leaf morphology ( Q. agrifolia, Q. alba, Q. cerris, Q. chrysolepis, Q. coccifera, Q.faginea, Q. frainetto, Q. ilex subsp. ballota, Q. ilex subsp. ilex, Q. petraea, Q. pyrenaica, Q. robur, Q. rubra, Q. suber , andQ. velutina ). To describe leaf-edge roughness, we used simple indices: P/L - the ratio of leaf perimeter (P) to maximum leaf length (L) along the main nerve; P/A - the ratio of leaf perimeter to leaf-blade area (A) and its dimensionless version (P/A0'); and WM/Wm -the ratio of maximum distance from the lobe tip to the main nerve (WM) to minimum distance from the lobe incision to the main nerve (Wm). There was a strong positive relationship betweenFDband P/A. Clustering analysis revealed the existence of three groups of leaves, namely those with: smooth or spiny margins (e.g.,Q. coccifera, Q. velutina ), shallow lobes (e.g.,Q. petraea ), and deep lobes (e.g.,Q. pyrenaica ). In the studiedQuercusspecies, the ratio WM/Wm is a simple and suitable leaflobation index. It is suggested that the flux rate along the leaf edge is related to the complexity of this boundary.

[学科分类] 植物学

[关键词] complexity;fractal dimension;leaf lobation;box-counting method;oak