Laguncularia Racemosa Leaves from a Mangrove of the Southeast Atlantic Coast, Brazil: Epicuticular Wax, Morphoanatomical Traits and Minerals

Leaves of Laguncularia racemosa (L.) Gaertn. f. were collected from the following mangroves along Brazil’s southeastern Atlantic coast: Coroa Grande (CG), Pedra de Guaratiba (PG) and Marambaia (M). This work aimed to evaluate the presence of minerals by Energy Dispersive X-Ray Spectroscopy (EDS) and Inductively coupled plasma - optical emission spectrometry (ICP-OES); the chemical composition of epicuticular waxes by gas chromatography–mass spectrometry (GC-MS) and the leaf morphoanatomical features. Results revealed variation in metal contents among mangroves in the following ranges: Al (0.307–0.73), Cd (0.004–0.016) and Pb (0.095–0.325) mg/mL by ICP-OES. Leaf epicuticular wax contained more than 50% of triterpenes, in particular the pentacyclic triterpenes lupeol (41.61–55.63%) and β-amyrin (8.81–16.35%), as well as n-alkanes, such as hentriacontane and tetratetracontane. In particular, we observed differences in the micromorphology of the epicuticular wax in the leaves of plants from each of the three evaluated sites, especially around stomatal entrances. Histochemical reaction indicated the presence of zinc in fiber cell walls and druse crystals of leaves.