Correlating Structure and Morphology of Andiroba Leaf (Carapa guianensis Aubl.) by Microscopy and Fractal Theory Analyses

The Amazon rainforest is considered a megadiverse biome, where several species of its rich flora are still unknown. The anatomy of their leaves usually identifies species. In this paper, we present a complete characterization of the leaf surface of Amazon Carapa guianensis Aubl. (Andiroba), using microscopy and fractal theory to be considered a possible tool for investigating different leaves spatial patterns, especially in species with similar leaf architecture. The SEM results revealed the cellular structures and other non-cellular structures that make up the leaf architecture, both for the abaxial and adaxial sides. The cells responsible for the plant photosynthesis process were observed in the internal structure of the leaf. The wettability analysis showed that the abaxial side is more hydrophobic, while the adaxial side is more hydrophilic. AFM images exposed the relevant details of the microstructure of the leaf abaxial side, such as stomata, pores, furrows, contour, particles, and rough profiles generated by topographic irregularities. The statistical parameters revealed that the scale size influences the topographic roughness, surface asymmetry, and shape of the height distribution, also observed by advanced parameters obtained according to the standard of the international organization for standardization (ISO). The fractal and advanced fractal parameters confirmed changes in spatial patterns as a function of scale size. The largest area exhibited greater spatial complexity, low dominant spatial frequencies, more excellent surface percolation, intermediate topographic homogeneity, and high uniformity of spatial patterns.