Anatomy of Sugar Apple (Annona squamosa L.) Seeds (Annonaceae)
The sugar apple is of great economic importance to the country, however, information on the anatomical and morphological aspects of Annonaceae family seeds is limited to a few species and the anatomical studies refer to very few seeds. Using histological techniques and microscopy, Annona squamosa L. seeds were studied with regard to their anatomical characteristics. In general, they presented the typical anatomical patterns of seeds of the Annonaceae family. The multilayered testa was comprised of exo-, meso- and endotestas, with the presence of longitudinal and oblique fibers. The embryo was small and straight with moderately developed embryonic axis, rudimentary plumule and flat and thin cotyledons, wherein one could observe the procambium. In particular, the perichalaza was observed in the medium longitudinal plane of the endotesta with more than two rows of vascular tissue. The tegmen or inner integument was collapsed. The micropylar plug was tapered, woody and composed of transverse fibers; a fracture line was also observed. The ruminate endosperm interfered with both the inner and external integuments. Oleiferous idioblasts were observed at the outer edges of the ruminations.