Morphoanatomy and ontogeny of Bactris maraja seedlings during initial development

Abstract

Bactris maraja is a palm typical of upland and lowland forests in the Amazon. Knowledge about the species´ morphology can assist in the correct identification in the field and in the interpretation of germination in the laboratory. The objective of this work was to describe the chronological and morphological patterns of germination and seedling development. The seeds were sown in vermiculite, in nursery. Samples were collected from the different stages of the seedling for further morphological analysis. The anatomical study was performed using sections of material fixed in neutral buffered formalin and preserved in 70% ethanol, stained with astra blue and safranin and observed in optical microscope. Germination is cryptocotyledonary, hypogeal and adjacent ligular, starting at 152 days with the emission of the short cotyledonary petiole. The protrusion of the primary root occurred at 197 days. The expansion of the eophyll occurred at 250 days, with a bifid and spinous leaf blade, an epidermis with tetracytic stomata, tectorial trichomes and collateral vascular bundles. The primary root has thick epidermis, thin cuticle, sclerenchymatic and parenchymal cortex, conspicuous endoderm; vascular cylinder with sclerenchyma medulla, exarco primary xylem, with protoxylem with polyarc arrangement. The characterized structures expand the taxonomic knowledge of palm species.