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Abstract
Ecophysiological characteristics of a sexual population of Chara canescens from Austria (NS) were compared with those from a parthenogenetical propagating population of the Baltic Sea (BS) to find out whether differences in salinity or irradiance acclimation abilities are responsible for the absence of male organisms in the Baltic Sea. Growth, photosynthesis main characteristics and pigmentation were examined at two irradiance levels and four salinities. Shoot elongations were highest for all specimens from both populations at low salinities. Reduction of growth at 12.4 PSU was less pronounced for NS female algae, whereas BS female and NS male algae showed strong growth reduction. Algae from NS had highest Pmax (maximum photosynthesis rate) and α-values (efficiency of light utilization at limiting irradiance) at 1.9 PSU, strongly decreasing at higher salinities. Both parameters were independent of salinity for BS algae. No significant differences between the experimental groups were found with respect to irradiance acclimation. Our results indicate that the absence of male C. canescens in the Baltic Sea is not related to sex-specific ecophysiological characteristics.
Acknowledgements
This study was funded by the Deutsche Forschungsgemeinschaft (FKZSchu983/8-1/2). Thanks go to Prof A. Herzig and all members of the Limnologische Station Illmitz and to the administration for the National Park Neusiedler See–Seewinkel (Austria) and A. Küster, who first found that there are still males in this region in 1999.