Schütz and Rave (1999), however, evaluated germination in light and dark of seeds of 18 Carex species from open, wetland habitats in Germany, the Czech Republic and Sweden. What is the predicted response of Carex seeds to these disturbances in sedge meadows? For many Carex species from prairie wetlands it is not known whether seeds germinate readily in the dark or if their emergence from the seed bank is restricted to disturbances that expose seeds to adequate light. Small-scale disturbances in sedge meadows include burrowing, trampling and grazing by mammals and waterfowl ( Fritzell, 1989 Murkin, 1989 Swanson and Duebbert, 1989). In wetland plant communities, emergence of light-requiring species from the seed bank is triggered by a disturbance when soil turnover, decline in water depth, or gaps in litter or the plant canopy ( Leck, 1989) expose seeds to light or higher R : FR. Many wetland species require light for germination compared with upland species ( Grime, 1981). Both the amount of light and quality of light are environmental cues that signal conditions potentially suitable for seedling establishment and survival ( Pons, 2000). In wetland plant communities, species-specific dormancy break and germination requirements influence emergence from the seed bank ( van der Valk and Davis, 1978 Leck, 1989 Baskin and Baskin, 1998). The specific factors that drive emergence from the seed bank and vegetation dynamics in sedge meadows, however, are not well understood in comparison to what is known about the dynamics of the emergent plant community ( van der Valk and Davis, 1978 Kantrud et al., 1989 Murkin et al., 2000). van der Valk and Davis, 1978 Welling et al., 1988 Seabloom et al., 1998). Seed bank dynamics of prairie wetlands have been the focus of a number of studies (e.g. In the prairie pothole region of mid-continental North America, >60 species of Carex are found in wetland habitats ( Barkley, 1986), especially sedge meadows, the seasonally flooded zone of prairie wetlands.

Conclusions The species-specific responses to simulated field light conditions suggest that ( a) the light requirements for germination contribute to the formation of persistent seed banks in these species and ( b) in revegetation efforts, timing seed sowing to plant community development and avoiding cover crops will improve Carex seed germination.Ĭarex, far-red light, seed germination ecology, photomorphogenesis, phytochrome, prairie wetland, red light, sedge, white light INTRODUCTIONĬarex is a globally important genus with >2000 species worldwide ( Bernard, 1990), and in many wetlands of the northern hemisphere, Carex species are the dominant vegetation.

The induction of germination after exposure to white or red light was reversed by far-red light in all species, except C. The effect of white light was replaced by red light in all species. Carex brevior required <15 min of white light for ≥50 % germination, while C. Germination responses after exposure to different lengths of white light varied widely across the eight species. stipata germinated >25 % in continuous darkness.

Methods Non-dormant seeds of eight Carex species were used to determine the influence of light on germination by examining: ( a) the ability of Carex seeds to germinate in the dark ( b) the effect of different lengths of exposures to white light on germination ( c) whether the effect of white light can be replaced by red light and ( d) whether the germination response of Carex seeds to white or red light is photoreversible by far-red light.The effects of light on germination in eight Carex species from prairie wetlands were investigated. Little is known about how light affects seed germination in these species-information which is necessary to predict seed bank emergence and to develop optimal revegetation practices. Carex species are the characteristic plants of sedge meadows of natural prairie wetlands in mid-continental USA but are not returning to restored wetlands. Background and Aims In wetland plant communities, species-specific responses to pulses of white light and to red : far-red light ratios can vary widely and influence plant emergence from the seed bank.

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