Characteristic values of key ecophysiological parameters in the genus Carex

With ca. 2000 species, the genus Carex (Cyperaceae) is one of the most species rich genera of phanerogams. It has an extended geographical and ecological distribution and is therefore favourable for comparative ecological and ecophysiological studies. In this overview, some key ecophysiological traits of Carex are reported, including: germination biology, internal transport and exchange processes, adaptations to waterlogging, nutrition physiology, and gas exchange behaviour. Data are given for individual species and for sedge canopies. Carex species are specialised for a wide range of different habitats, and thus vary considerably ecophysiologically. This variation has lead to wide ranges in key ecophysiological values, including: 1) the cross sectional proportion of leaf aerenchyma ranges from 9 to 90%, 2) the oxygen loss at the roots is between 0.04 and 1920 nmol cm(root surface)(-2) min(-1), 3) the potassium content varies between 4 and 53 mg g(dry weight)(-1), 4) the chlorophyll content is between 1.4 and 20.8 mg g(dry weight)(-1), 5) the species specific maximum leaf conductance is between 0.13 and 1.0 mol m(-2) s(-1), 7) the maximum net-assimilation rates reach 2 to 34 mu mol m(-2) s(-1), 8) the canopy transpiration of sedge stands goes up to 8.8 mm d(-1), and 9) the canopy CO2 uptake is up to 44 g m(-2) d(-1).