The study used fractal analysis to evaluate and describe the geometry of the leaves at the Populus alba L. specie. The leaf samples were taken randomly, from mature trees, from the Cenad Forest Protected Area, Timis County, Romania. The leaves were scanned in a 1:1 ratio, and binarized images of the leaves were used for fractal analysis of leaf geometry. The box-counting method was used for the fractal analysis in order to obtain the values of the fractal dimensions (D). Foreground pixels (FP), correlation coefficient R2 for D, and standard error (SE) were recorded. The values of the parameters of the leaves L (leaf length), w (leaf width), Per (perimeter), and SLA (scanned leaf area) were determined. The ANOVA test (Alpha = 0.001) confirmed the statistical safety of the data and the presence of variance in the data set (p <0.001, F> Fcrit). The coefficient of variation (CV) indicated the values: CVL = 14.910 for the leaf length parameter (L), CVw = 19.531 for the leaf width parameter (w), CVPer = 16.865 for the leaf perimeter (Per), CVSLA = 33.594 for the scanned leaf area (SLA), CVFP = 33.151 for foreground pixels (FP), and respectively CVD = 2.838 for fractal dimension (D). From the comparative analysis of CV values, it was found that the smallest variation was recorded in the case of fractal dimension (D), and the largest in the case of scanned leaf area (SLA). This suggests that the fractal dimension (D) is the most stable parameter in the characterization of leaf geometry in the species Populus alba L. Diversity profile indicated a similar distribution of the studied parameters. In relation to the dimensional parameters of the leaves, the variation of the fractal dimensions (D) had variable interdependence relations, in conditions of R2 = 0.878 in relation to FP, R2 = 0.908 in relation to Per, R2 = 0.909 in relation to SLA, R2 = 0.799 in relation to L and, respectively, R2 = 0.698 in relation to w. Polynomial equations, of degree 2, described the variation of the fractal dimensions D in relation to FP, Per and SLA, in statistic safety conditions, p <0.001.

box-counting, diversity profile, fractal analysis, leaf geometry, Populus alba

biology

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