Anatomical and histochemical characterization of coconut leaflets

Abstract

We studied the anatomy and histochemistry of Cocos nucifera leaflets aiming to improve the knowledge about the species and give future support to the research on coconut-foliar pathogens interaction. Fragments of the middle region of the leaflets were collected and used in this study. This material was processed for analysis by light microscopy and scanning electron microscopy. For histochemical study, transversal sections of fresh material were subjected to various histochemical tests. The anatomical analyzes revealed the presence of uniseriate epidermis, coated with plate-like epicuticular waxes. Tetracytic stomata and stellate trichomes were mainly observed on the abaxial face of epidermis. The dorsiventral mesophyll showed 2-3 layers of palisade, 4-5 layers of spongy parenchyma and collateral vascular bundles surrounded by sclerenchymatous pericycle. Idioblasts containing calcium oxalate crystals or phenolic compounds were also observed in the mesophyll. The anatomical and histochemical results observed in leaflets of C. nucifera may be involved in the interaction coconut-leaf pathogens.