Morfologia dos esporos da família Bechnaceae Newman (Polipodiales - Polypodiopsida)

Abstract

Blechnaceae, a family of leptosporangiatae ferns, is a monophyletic group with controversial infrageneric relationships, resulting in different classifications. In order to contribute to the most recent classification of the group, this work aims to detect if the spore morphology contributes to the recognition of different genera in the current phylogenetic classification recognized for the group.To meet this goal, the spores of 53 species and one hybrid, distributed in 18 genera, were examined. The spores were collected in the herbarium was submitted to acetolytic treatment. The acetolysed spores were measured, described and the results submitted to statistical analysis. After making the slides, the images of the acetolyzed spores were made in light microscopy. Non-acetylated spores were used for scanning electron microscopy images. The spores are plane- convex in equatorial view and ellipsoidal in polar view, medium to large size, with monolete laesura of varied size, linear and without margin. The exine is formed by two layers, nexine and sexine, psilate in most species, except in Stenochlaena. The perine has three layers except for the subfamily Stenochlaenoideae which recorded only one. Two large groups were segregated according to folds of the perine, without cristae and cristae and great diversity of ornamentation on the surface of the spore. Among the spores without cristae are Austroblechunm and Doodia with granulate or scabrate ornamentation. Neoblechnum is scabrate, Sadleria is thickly gemate, both of scaly aspect. Salpichlaena and Telmatoblechnum have granules and gemmae. Stenochlaena recorded fine perine outline the exine forming equine ornamentation or with parallel dense folds. The group that recorded cristae comprises Anchistea with presence of spines, Cranfillia and Struthiopteris with psilate cristae or ripples, Diploblechnum from psilada to granulate, Icarus with rugular ornamentation. Lomaria and Lomaridim present rugulae and granules, Blechnum and Lomariocycas were the most diverse, probably due to the influence of polyploidy that promotes morphological diversity, both presented a single cristae species, Blechnum with granulate, scabrate, rugulate and psilate ornamentation, Lomariocycas conspicuously rugulate or densely gemmate. Parablechnum was characterized by cristae of high and low walls with filaments or not, Woodwardia has scrabate ornamentation. Morphometric analysis was not a useful tool for the segregation of taxonomic groups in the genus by possible influences of polyploid specimes. In contrast, the analysis of the spore surface ornamentation allowed the delimitation of the genera according to the ornament folds of the perine, corroborating with the new classification proposed for the family, also proving the importance of Palinology for the segregation of taxa and provided important information on the different variations of the perina ornamentation, contributing to the enrichment of the group's palynological knowledge.