Pollen morphology of Mourera (Podostemaceae)

ABSTRACT

The pollen morphology of Mourera (Podostemaceae) was analysed with the aim of providing detailed descriptions of pollen for all species of the genus. Pollen grains were obtained from anthers of flower buds, acetolysed, and examined using light and scanning electron microscopy. The pollen grains are monads, small or medium sized, prolate in shape, with a circular or subcircular amb. Pollen grains are tricolpate, and the colpus was variously ornate and has distinctive ornamentation between apertural and non-apertural regions. The exine is thin and microechinate with supratectal spines in all species. In M. fluviatilis, M. monadelpha and M. schwackeana the surface has inconspicuous spines without delimited basis; in M. alcicornis, M. aspera, M. elegans and M. weddelliana, the surface has spines at the apices of ‘mamiloid elements’, with a wide base of spines individualised and well defined. Hierarchical cluster analysis (HCA) was used to divide the main pollen taxa into three groups based on pollen morphology. Statistically distinctive taxa were identified using principal component analysis (PCA). Pollen analysis revealed a significant overall correspondence between pollen variations amongst species of Mourera and phylogenetic patterns.

KEYWORDS:

• Hierarchical cluster analysis
• palynology
• podostemoideae
• ultrastructure

Acknowledgements

We are grateful to the curators of the herbaria listed in the Materials and methods for providing the opportunity to pick up palynological samples. The first author thanks Capes (Coordenação e Aperfeiçoamento de Pessoal de Nível Superior) for a doctorate grant; Gonçalves-Esteves, Mendonça and Bove extend their thanks to the CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico) for a Productivity Grant. The authors are grateful to the technicians at the Laboratory of the Department of Invertebrates of the National Museum of the Universidade Federal do Rio de Janeiro for the SEM images.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by CNPq [grant numbers PROTAX 562251/2010-3 and REFLORA 563534/2010-9], and FAPERJ [grant number APQ1-E26/111,214/2014].

Notes on contributors

Elysiane de Barros Marinho

ELYSIANE DE BARROS MARINHO is graduate in biology (2008) and Bacharel in biology marine (2009) at the Faculdades Integradas Maria Thereza, Specialization in Education (2010) at the Universidade do Estado do Rio de Janeiro –FFP/UERJ, master's at Botany (2013) and PhD degree in botany at the Universidade Federal do Rio de Janeiro - Museu Nacional /UFRJ. She is currently involved in the project “Systematics of Neotropical Podostemaceae”, with the subproject “Palynotaxonomy of Neotropical Podostemaceae” and “Palynotaxonomy of Sapindaceae”.

Claudia Petean Bove

CLAUDIA PETEAN BOVE is a research fellow at the Conselho Nacional de Desenvolvimento Científico eTecnológico in Brazil, and is Titular Professor in the Department of Botany at the Museu National. She has a batchelors degree in ecology (awarded in 1983), a masters degree in botany (awarded in 1990) and a PhD degree in biology (awarded in 1996). Her research is currently focused on the systematics, phylogeny and biogeography of the Podostemaceae, the biology of aquatic vascular plants and freshwater ecosystems.

Claudia Barbieri Ferreira Mendonça

CLAUDIA BARBIERI FERREIRA MENDONÇA is a professor in the Department of Botany of the Universidade Federal do Rio de Janeiro, Museu National and she is a research fellow at Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). She is graduated in biological sciences, master's and PhD degree in biological sciences (Botany) at the Universidade Federal do Rio de Janeiro, Museu Nacional (1999/2006). Her research involves Palynology of the current flora in several Brazilian ecosystems.

Vania Gonçalves Lourenço Esteves

VANIA GONÇALVES LOURENÇO ESTEVES is Titular professor in the Department of Botany of the Universidade Federal do Rio de Janeiro, Museu National and is a research fellow at Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq). She received a graduate degree in biological sciences (Botany) at the Universidade do Estado da Guanabara (1974), master's degree in botany (Palynology) at the Uiniversidade Federal do Rio de Janeiro, Museu National (1981), and PhD degree in biological sciences (Palynology) from the Universidade de São Paulo (1994). Her research involves Palynology of the current flora in several Brazilian ecosystems.