Microscopical observations of crystal deposits on the epidermis of leaves of Agave potatorum.

Calcium oxalate crystals were observed on the leaf epidermis of Agave potatorum surrounding the stomatal complex. Their morphology corresponded to the styloid type, and the chemical composition using EDS spectrum confirms calcium oxalate. A significantly higher abundance of crystals was observed on the adaxial leaf side in comparison with the abaxial side (p < 0.05). Crystals grew up in bundles in a range of 6-8 elements into idioblasts. A light microscope reveals that these crystals reflect part of the incident light. Cuticle from the abaxial leaf side was thicker and had a special structure formed by six papillae surrounding a larger central papilla, which was observed as star-like. This could be related to the evolutionary adaptation of this Agave species to drought stress conditions.