Two parthenogenetic populations of Chara canescens differ in their capacity to acclimate to irradiance and salinity

Abstract

The parthenogens of Chara canescens (Charophyceae) occupy broader geographical and ecological ranges than their sexual counterparts. Two possible hypotheses explain the ubiquity of parthenogens: the occurrence of one or several parthenogens with wide niches, or of many parthenogens that are restricted to narrow ecological niches. For the purposes of this study, C. canescens individuals from two neighbouring populations of the Baltic Sea (Bodstedter Bodden = BB; Salzhaff = SH), which differed significantly in water transparency and salinity, were investigated for significant differences in physiological capacity. Individuals of both habitats acclimated quickly to daily changes in irradiances in the field, but the photosynthetic efficiency of PS II showed a significant decrease with increasing daily irradiance in the habitat BB, which has lower levels of salinity and water transparency. In addition to the field study, individuals were reared under different levels of environmental factors in the laboratory: four irradiances (70-600 μmol m(-2) s(-1)) and five salinity levels (0-24 psu). The individuals of both habitats grew almost equally well at intermediate salinity levels. Growth under the artificial light supply was highest at levels corresponding to the in situ conditions for each population. Total chlorophyll was highest at intermediate salinities (BB), or hardly changed with salinity (SH). The physiological capacity for individuals from SH clearly depends upon changing growth irradiance, whereas the capacity for individuals from BB was relatively independent of salinity and irradiance. These findings indicate that both parthenogenetic C. canescens populations are locally adapted to light. However, to test adaptive potential of the parthenogens, more than two populations should be tested in future.

Plastid DNA sequences and oospore characters of some European species ofTolypellasectionTolypella(Obtusifolia, Characeae) indicate a new crypticTolypellaspecies from the Mediterranean island Sardinia

“…Nevertheless, both analyses could be considered as appropriate, and imply possibilities for further investigations of the species status of these European taxa such as analyses of geographically isolated Tolypella populations on the basis of Simple Sequence repeats as microsatellite studies have shown for the genus Chara (Schaible et al, 2012, Noedoost et al, 2015). NGS- techniques, multi-omics approaches including proteomics could be carried out to examine smallest genetic differences as shown for Nitellopsis obtusa (Sleith and Karol, 2021).…”

Algae in Shallow and Small Water Bodies of Serbia: A Frame for Species and Habitat Protection

“…Populations found across Europe are mainly parthenogenetic (as well as the one in Serbia), bisexual populations are extremely rare [107,109]. One more specific characteristic of the species is semelparity [106,110], which might explain why Vesic [88] has not made a record when surveying the Plava Banja pond.…”

Rediscovery of Chara canescens Loiseleur in Serbia

“…In a parthenogenetic population of C. canescens, asexual reproduction is obligatory and irreversible; specimens cannot reproduce vegetatively, but only by oospore germination. Being an annual species, growth is fast and reproduction relies on semelparity for sexual as well as parthenogenetic individuals (Blindow & Schubert 2004;Schaible et al 2012). Extant bisexual populations are extremely rare and limited to a few localities in Europe -Austria (the border area between Austria and Hungary) and Spain (Cirujano et al 2008;Schaible & Schubert 2008;Schaible et al 2011).…”