The main objective of this work was to evaluate the dynamics of CO2 and CH4 emissions from wetland soil of the sedge-grass marsh, which belongs to large complex of wet meadows near Třeboň town. CO2 and CH4 emission measurements realized on six places, where gas emission collars permanently inserted. Finally, samples of air were taking with using manual emission gas chambers within period from April 25th to November 24th 2014. The highest fluxes of CO2 were recorded in June and July. The lowest water level was recorded in this period together with low fluxes of CH4. Methane emissions were higher in September and October at the time where water level was above soil surface. Range of CO2-C fluxes was -9.38 mg m-2 h-1 (consumption) to 147.84 mg m-2 h-1 (emission). Range of CH4-C fluxes was -14.94 ?g m-2 h-1 (consumption) to 5561.67 ?g m-2 h-1(emission).

This thesis is part of Project of the Grant Agency of the Czech Republic No P504/11/1151, focused on the role of plants in the balance of carbon dioxide and the other greenhouse gases produced in the ecosystem of a sedge fen, which is situated on the study site Wet Meadows near Třeboň. The thesis deals with the growth dynamics of the dominant sedge, Carex acuta. The samples were taken using the method of successive harvests near the automatic meteorological station of Czech Globe, Academy of Sciences of the Czech Republic. During the growing season nine harvests were accomplished on 25.3, 15.4, 6.5, 5.6., 9.7., 5.8., 9.9., 21.10., 25.11.. On each date eight replicates were taken, i.e., a total of 72 samples within the vegetation season. The seasonal dynamic of the above ground biomass was compared between C. acuta and the other plant species on the experimental area. Both live and dead biomass, was harvested and subsequently sorted to single botanic species, dried, weighed and the values were processed using the MS Excel tables. The seasonal maximum of aboveground biomass of all plant species (both live and dead parts) was found on 9.7. (1452,72 g.m-2). Among plant species the highest values of aboveground biomass were attained by Calamagrostis canescens (1257,93 g.m-2) and C. acuta (1163,49 g.m-2). C. acuta displayed the highest density of all shoots on 15.4 (300 m-2),and the highest average weight of one shoot. The maximum length of the longest live shoot of Carex acuta was very consistent among the measurememnts.