Morphological and cytological variation in Spergularia echinosperma and S. rubra, and notes on potential hybridization of these two species.

Pavel Kúr 1 , Milan Štech 1 , Petr Koutecký 1 & Pavel Trávníček 3 2

Affiliations

  1. Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 31, CZ-370 05 České Budějovice, Czech Republic
  2. Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, CZ-252 43 Průhonice, Czech Republic
  3. Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic

Published: 8 October 2012


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Abstract

Morphological and cytological variation in Spergularia echinosperma and S. rubra and the possibility of these two species hybridizing were investigated. The plant material was collected mainly in the western- and southern-Bohemian pond basins where S. echinosperma is most abundant. Using flow cytometry, we found diploid and tetraploid cytotypes among plants morphologically identified as S. echinosperma and only tetraploid S. rubra. The two tetraploid cytotypes differed significantly in genome size. Both the diploid and tetraploid S. echinosperma and S. rubra also differed morphologically. The most important identification characters were stipule length together with stipule length/width ratio, seed colour, seed size and testa verrucosity. Although the morphological data suggest that tetraploid S. echinosperma may be a hybrid between diploid S. echinosperma and S. rubra, its genome size was significantly greater than that of a simulated allotetraploid. Since an increase in genome size following allopolyploidization is an improbable event, it is possible that other pathways were involved in the formation of tetraploid S. echinosperma. The nomenclature of S. echinosperma was also studied. Lectotypification of the name with a plant morphologically corresponding to the diploid cytotype is proposed. The morphological analysis also indicates that the holotype of S. ×kurkae, which was described as a putative hybrid between S. echinosperma × S. rubra, corresponds to tetraploid S. echinosperma.

Keywords

allopolyploidy, classification trees, discriminant analysis, flow cytometry, genome size, inter-ploidy hybridization, morphometric analysis, Spergularia

How to cite

Kúr P., Štech M., Koutecký P. & Trávníček P. (2012) Morphological and cytological variation in Spergularia echinosperma and S. rubra, and notes on potential hybridization of these two species. – Preslia 84: 905924