Passifloraceae shows a huge variability of pollen wall characteristics, most still little described. Passiflora is the largest genus with about 580 species with tropical distribution. Few studies in palynological approaches have described the intine layer which can fill existent gaps. Passiflora L. present four subgenera, from which Passiflora, Astrophea, and Decaloba were described in this study. The pollen wall variations were poorly studied, with the objective of describing the morphological and histochemical structure of Passiflora sporoderm that occurs in South America, aims to supply more pollen wall characters in some contexts. Besides the inference of evolutive trends, we described the number of apertures, type, reticule, and variations of the morphology and sporoderm and we related them with possible evolutive trends for the group. As a result, the pollen grains were not far from the patterns found by the literature, with exceptions. The species of the subgenus Passiflora have fused colpi, varying from 6 to 12 colpi, with type 2-reticulate exine. The species of the subgenus Astrophea have colporus and the species of Decaloba varied as the type of aperture, in which a new type of exine to be considered was found: the type 3. The subgenus Passiflora showed the thickest intine, slim endexine, and absent foot layer. While the species that belong to the other subgenera present a slim intine, the endexine is thick and the foot layer is continuous, among other variable characteristics. The size of the pollen grain seems to be related to the thickness of the intine, and consequently, related to possible pollinators. Through the cluster analysis, we reinforce the affinity of the species to its respective subgenus. To conclude, the analysis of the ultrastructure of the sporoderm and external morphology would be useful for an almost complete interpretation of the variations occurring in the genus, giving more information that the subgenus Passiflora is apomorphic when compared to the other two. The pollen wall characters should be considered on the interpretation of natural history, as well as the phylogenetic relationships of the family, mainly in the Passiflora genus, that has a large number of species distributed across the Neotropical regions.
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The authors would like to thank Adriana Carolina Aguirre Morales and Miguel Bonilla Morales for their help in collecting fields in Colombia and the Laboratório de Genética e Evolução, Laboratório de Bioenergia and Centro de Ciências Moleculares e Nanotecnologia da UNICENTRO for support during the image collection. The article is part of the dissertation of the first author that was sponsored by a CAPES master’s degree scholarship.
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Conflict of interest
The authors declare that they have no conflict of interest.
El-Tantawy AA, Solis M-T, Risueno MC, Testillano PS (2014) Changes in DNA methylation levels and nuclear distribution patterns after microspore reprogramming to embryogenesis in barley. Cytogenet Genome Res 143:200–208. https://doi.org/10.1159/000365232CrossRefGoogle Scholar
Erdtman G (1952) Pollen morphology and plant taxonomy – angiosperms. Almqvist & Wiksell, StockholmGoogle Scholar
Erdtman G (1960) The acetolysis method. A revised description. Svensk Bot Tidskr 39:561–564Google Scholar
Erdtman G (1969) Handbook of palynology. Munksgaard, CopenhagenGoogle Scholar
Evaldt ACP, Bauermann SG, Cancelli RR, Acioli M, Neves PCP (2011) Morfologia polínica de Passifloraceae Juss. ex Kunth. no Rio Grande do Sul, Brasil. Rev Bras Biol 9:75–87Google Scholar
Fazal H, Ahmad N, Abbasi BH (2013) Identification, characterization, and palynology of high-valued medicinal plants. Sci World J 2013:1–9CrossRefGoogle Scholar
Feuillet C, MacDougal JM (2003) A new infrageneric classification of Passiflora L. (Passifloraceae). Passiflora 13:34–35 37–38Google Scholar
Feuillet C, MacDougal JM (2007) The families and genera of vascular plants. In: Kubitzki K (ed) Passifloraceae. Springer, BerlinCrossRefGoogle Scholar
Galen C (1999) Why do flowers vary? The functional ecology of variation in flower size and form within natural plant populations. BioScience 49:631–640CrossRefGoogle Scholar
Gerrits PO, Smith L (1983) A new, less toxic polimerization system for the embedding of soft tissue in glycol methacrylate and subsequent preparing of serial section. J Microsc 132:81–85CrossRefGoogle Scholar
Milward-de-Azevedo MA, Freitas LB, Kinoshita LS (2014) Taxonomy and evolutionary relationships of Passiflora subg. Decaloba supersect. Decaloba sect. Xerogona (Passifloraceae): contributions of palynological, morphological and molecular studies. Acta Bot Bras 28:301–30Google Scholar
Milward-de-Azevedo MA, Baumgratz JF (2004) Passiflora L. subgênero Decaloba (DC.) Rchb. (Passifloraceae) na região Sudeste do Brasil. Rodriguésia 55:17–54CrossRefGoogle Scholar
Milward-de-Azevedo MA, Gonçalves-Esteves V, Baumgratz JF (2010) Palinotaxonomia das espécies de Passiflora L. subg. Decaloba (DC.) Rchb. (Passifloraceae) no sudeste do Brasil. Rev Bra Bot 27(4):655–665CrossRefGoogle Scholar
Porter-Utley K (2014) A review of Passiflora L. subgenus Decaloba (DC.) Rchb. super section Cieca (Medik.) MacDougal JM and Feuillet C (Passifloraceae). PhytoKeys 43. https://doi.org/10.3897/phytokeys.43.7804
Presting D (1965) Zur morphologie der Pollenkörner der Passifloraceen. Pollen Spores 7:193–247Google Scholar
Punt W, Hoen PP, Blackmore S, Nilsson† S, le Thomas A (2007) Glossary of pollen and spore terminology. Rev Paleobot Palynol 143:1–81CrossRefGoogle Scholar
Reis NR, Peracchi AL, Pedro WA, Lima IP (eds) (2007) Morcegos do Brasil. Universidade Estadual de Londrina, LondrinaGoogle Scholar
Richards AJ (1986) Plant breeding systems. George Allen & Unwin, LondonGoogle Scholar
Sazima M, Sazima I (1978) Bat pollination of the passion flower, Passiflora mucronata, in southeastern Brazil. Biotropica 10:100–109CrossRefGoogle Scholar
Snow AA (1982) Pollination intensity and potencial seed set in Passiflora vitifolia. Oecologia 55:231–237CrossRefGoogle Scholar
Soares L, Jesus ON, Souza EH et al (2017) Comparative pollen morphological analysis in the subgenera Passiflora and Decaloba. An Acad Bras Cienc 92:2381–2396CrossRefGoogle Scholar
Spirlet ML (1965) Utilisation taxonomique dês grains de pollen de Passifloracées. Pollen Spores 7:249–301Google Scholar
Stroo A (2000). Pollen morphological evolution in bat pollinated plants. Plant Syst Evol 25–242Google Scholar
Suárez-Cervera M, Arcalís E, Le Thomas A, Seoane-Camba, JA (2002) Pectin distribution pattern in the apertural intine of Euphorbia peplus L. (Euphorbiaceae) pollen. Sex Plant Reprod. 14:291–298Google Scholar
Varassin IG, Trigo JR, Sazima M (2001) The role of nectar production, flower pigments and odour in the pollination of four species of Passiflora (Passifloraceae) in South-Eastern Brazil. Bot J Linn Soc 136:139–152CrossRefGoogle Scholar