Cytogenetic features of sexual and asexual Limonium taxa (Plumbaginaceae)

The genus Limonium (sea lavenders) is characterized by various taxonomically challenging complexes with great karyological diversity, and chromosomes ranging in size from diminutive to large. In this biosystematie study, our goal was to investigate cytogenetic features of twelve sexual and asexual taxa in a particular part of their distribution range. Genome size, chromosome number variation, and other cytological features were investigated in a representative set of sea lavenders with distinct leaf venation, present in the coastal areas of the Iberian Peninsula, Morocco, France, and the Channel Islands. Flow cytometric genome size determinations were made in plants from natural populations. Cell and nuclear areas of epidermal cells, as well as, chromosome numbers and length were measured in plants from ex situ collections. Our findings revealed positive and significant correlations between holoploid genome size and cell size, nuclei area and chromosome total length. Tetraploid taxa with pinnately veined leaves had significant lower holoploid and monoploid genome sizes along with lower cell and nuclei areas and chromosome sizes than tetraploid taxa with parallel-veined leaves. The results obtained are discussed in the context of breeding relationships known or suspected among these taxa. In conclusion, our results provide a basis for future evolutionary studies, and support that pollen-stigma dimorphisms and genome size allied with chromosome counts might be important taxonomic traits in Limonium in apomietic/sexual groups.