Análise anatómica da região distal do hipocótilo de plântula de rhizophora mangle l.

Abstract

The Rhizophoraceae family has 16 genera and about 120 species, among which Rhizophora mangle L., which is lacking in studies of developmental anatomy. Therefore, this work aims to anatomically identify the structures of the distal region of the hypocotyl of Rhizophora mangle seedlings at different stages of development. The samples were collected in the municipality of Marapanin-PA, at Crispim beach, fixed in FAA and stained in astra blue and safranin. As for the anatomy of the roots, apparently adventitious, in cross section, they present in the proximal, median and apical region a unistratified epidermis. In the cortical region, an exodermis formed by elongated cells with thickened internal periclinal walls is observed and after the underlying cells there is installation of a phellogen, because in the proximal and median region the formation of periderm is already observed, besides the cortex contains many tanniniferous idioblasts and an evidenced endodermis. The vascular cylinder is poorly differentiated, so there is no clear distinction of phloematic and xylematic tissues, which will indicate the difference between root and stem. What is observed is the pericycle and the medullary parenchyma tending to sclerify centripetally. Therefore, it is still not possible to state whether the structures developed in the distal portion of the hypocotyl of Rhizophora mangue are adventitious roots or stem branches.