## 3 Results and Discussion  
### SEM Analysis  
Figure 1 shows images of the abaxial and adaxial sides of the epidermal surface of the Andiroba leaf. The presented set of images highlights the morphological difference between the sides. As can be seen, the abaxial side (Figure 1a-c) contained the structures expected for the taxonomy of this plant, explicitly, stomach cells, while the abaxial side (Figure 1d-f) exhibits a more striated tissue. Both leaf sides may contain all plant cells, but here only the abaxial side was observed, the stomata, which might be related to the climatic dynamics of the Amazon rainforest. This absence of stomach cells is typical behavior that has been reported for the adaxial side of Nepenthes species [51]. The stomata in the abaxial side, highlighted by the red arrows (Figure 1b), are cells specialized in gas exchange with the medium [52; 53]. These cells are separated by polygonal structures formed by clusters of common epidermal cells, as can be noted in Figure 1a. In the stomata pore (Figure 1c), we can see a slit that allows gases to enter and exit; hence it  
Figure 1: SEM images of Andiroba leaf surface. The following magnifications were applied: (**a**) \(\times\)350, (**b**) \(\times\)750, and (**c**) \(\times\)3500 for Abaxial side and (**d**) \(\times\)350, (**e**) \(\times\)1000, and (**f**) \(\times\)1500 for Adaxial side. also controls the water outlet [54]. Figure 1e,f, show the clustering of typical epidermal cells that form the epidermal tissue on the adaxial side. The thicker tissue provides additional protection against constant rainfall changes in the Amazon region. The environment in which the leaves were harvested most likely results in differences in the composition of the epidermis. In fact, in the Amazon rainforest, climate change can occur suddenly [55], where variations in temperature and water vapor in the forest can shift stomach cells, preferably for the abaxial part. The organic matter present on the forest floor can be a constant emitter of carbon dioxide [56], explaining the absence of stomach cells on the adaxial side. Moreover, the increasing fires in the Amazon may be providing an evolutionary mechanism to this plant, changing its leaf structure. More details of the microstructure of the leaf for both sides are shown in Figure 2, where, especially, Trichomes (leaf hairs) can be observed. Such cells (highlighted by white arrows in Figure 1a,b) are elongated and appear on both sides, suggesting that both leaf sides can have a protection mechanism against ultraviolet radiation [57], mainly on the adaxial side. Furthermore, these cells are specialized in expelling plant substances such as soap and water that helping against insect pests [58] and be a physical barrier against the weather. Additionally, Figures 1c and 2d revealed epicular wax, a widespread resin in plant leaves [59; 60]. The highest magnification obtained for the abaxial side Figure 2c shows a piece of the epicular wax that was removed to reveal the microstructure of the leaf. The presence of epicular wax in the leaf regulates the process of water loss and creates a barrier against toxic aerosol particles. It is also worth noting that this wax was not noticed around the pore, which was also observed for Anocardium occidentale L. leaves [53]. Figure 3 shows the main cells found along with the profile regarding the internal structure of the leaf. The main structures found in the mesophyll are the palisade parenchyma, lacunous parenchyma, xylem, and phloem, which are structures responsible for plant photosynthesis [61; 62]. The yellow arrows in Figure 3a,b highlight the watery parenchyma,  
Figure 2: SEM micrographs of the abaxial and adaxial side of the Andiroba leaf surface reveal (**a,b**) Trichomes and (**c,d**) epicuticular waxes for abaxial and adaxial sides, respectively. while the red arrow in Figure 3a highlights the palisade parenchyma. The leaf structures are divided into xylem (green arrows) and phloem (purple arrows) in the core.