Pollen morphology of selected species of Passiflora L. (Passifloraceae) from the Atlantic Forest

Abstract

Pollen grains from twelve species of the Passifloraceae family from the Brazilian Atlantic Forest were analyzed: Passiflora subg. Astrophea (1sp.), P. subg. Decaloba (1sp.) and P. subg. Passiflora (10spp.). The current study aims to acquire additional information and feature the pollen morphology of the herein studied species to help setting a more precise taxa delimitation. Acetolyzed pollen grains were measured, described and illustrated using light and scanning electron microscopy. The pollen grains were medium or large sized, oblate spheroidal, suboblate, prolate spheroidal and subprolate; 4-colpate (P. kermesina), 6-12-pantocolporate (P. mediterranea), 6-colpate (P. mucronata), 6-colporate (P. pentagona), 12-colporate (P. misera) or 6-syncolpate (in most species). The presence of reticulate sexine, pseudopercula, pontopercula and/or opercula was observed. The endoaperture was just found in P. pentagona and P. misera. It was concluded that pollen morphology is an important source of taxonomic features useful for distinguishing species and characterizing the three subgenera. The current study provides additional information that, along with other previously published studies, will enable a better understanding of phylogenetic relations among these strains.

Comparative pollen morphological analysis in the subgenera Passiflora and Decaloba

“…Some authors have affirmed that the oblate-spheroidal, prolate-spheroidal and spheroidal shapes confer the Passifloreaceae with one of their main palynological characteristics and may help in the taxonomic classification of this group (Mezzonato-Pires et al 2015b). …”

“…Based on these studies, some other research have focused on palynology in the differentiation of Passiflora and/or species (Amela Garcia et al 2002, Milward-de-Azevedo et al 2010, 2014a, Gabarayeva et al 2013, Mezzonato-Pires et al 2015a. However, few studies simultaneously analyzed different subgenera of the Passifloraceae (Mezzonato-Pires et al 2015b). Therefore, the objective of this work was to evaluate the pollen morphology of eighteen Passiflora species in order to identify informative pollinic characteristics to contribute to the taxonomic classification of the genus.…”

Palynotaxonomy of Brazilian species of Passifloraceae sensu stricto

“…However, specialized literature of the group presents divergent data. Pollen grains of both species are described as 12-colpate by Amela-Garcia et al (2002) and 6-colpate by Araújo & Santos (2004), 12-colporate for P. misera (Milward-de-Azevedo et al 2004;2010;Mezzonato-Pires et al (2015b) and 12-colpate for P. suberosa (Milward-de-Azevedo et al 2004;2010;Soares et al 2018).…”

Pollen morphology of selected species of tribes Ingeae and Mimoseae (Mimosoideae—Leguminosae) occurring in the Atlantic Forest of the state of Rio de Janeiro, Brazil

“…For descriptions and illustrations, a specimen considered as ''standard'' was selected for each studied species. In order to document morphometric variation, we studied, when possible, up to two specimens for each species as ''material for comparison'' (Mezzonato-Pires et al 2015).…”