Differences between peak-season and off-season dry mass, organic matter mass, and both concentrations and pools (standing stocks) of ash, N, P, K, Ca, Mg and Na were investigated in the rhizosphere soil, and live and dead aboveground plant biomass at 14 sites hosting 4 plant community types in the littoral zone of a eutrophic ancient shallow reservoir of about 5 km2 area, the Rožmberk fishpond (S. Bohemia, CZ). Comparisons between the peak-season and off-season data and several stoichiometric relations calculated from them provided an insight into the mineral nutrient economy of the examined types of the fishpond littoral vegetation. It is rooted in relatively nutrient-poor sandy soil, but differently enriched with nutrients contained in either the percolating fishpond water, or that of springs located at the landward edge of the littoral zone. The degree of eutrophication of our sampling sites and their vegetation thus seem to be positively correlated with the degree of contact of the plants´ rhizosphere with the nutrient-richer fishpond or spring water.

The paper summarizes data concerning the biology and ecology of Oenanthe aquatica. The species is commonly distributed all over Czechoslovakia, from lowlands to the submontane belt, especially in fishpond and river basins. O. aquatica shows no special relationship to the chemical and physical soil properties, and is well adapted to habitats with a changing water level. The reproduction of O. aquatica depends on emerging of the bottom. The most developed populations are formed by biennial plants and arise in the year following summer or autumn drainage.

The salt marsh vegetation on the west coast of North Korea was studied by the method of the Zürich-Montpellier school. The following communities were distinguished:Suaedetum japonicae, Scirpetum iseensis, Artemisietum fukudo, and the following were described as new:Triglochini maritimae-Phragmitetum communis, Artemisio capillaris-Salsoletum komarovii andSalsolo komarovii-Rosetum rugosae. The phytocoenological material was also analysed by means of numerical techniques.

The paper summarizes hitherto known data concerning the biology and ecology ofSagittaria sagittifolia. The distribution of this species in Czechoslovakia was assessed on the basis of literature data, herbarium specimens and the authors’ own data. The occurrence of this species in plant communities is shown in tables from selected phytocoenological relevés. The chemical properties of the substratum in habitats ofSagittaria sagittifolia over all its distribution area in Czechoslovakia were studied and comparisons calculated by means of cluster analysis. Life cycle, seed production, germination and biomass production of this species were studied and compared with conditions in its habitats.

Distributions of individual species and plant communities growing on the bottom of a medium-sized, 0.35 km2, Starý Vdovec fishpond near Třeboň, South Bohemia, were investigated during the summer-drainage of the pond. The community characteristics (phytocenological relevés, cover assessed by point-quadrat method, biomass and production, amounts of nutrients in biomass, species diversity, interspecies associations) as well as environmental characteristics (depth of pond sediment, position of water table, mineral nutrient concentrations and contents in the soil, soil pH) were evaluated. The sediment depth and position of water level were distinguished as the most important environmental factors; other characteristics of both the vegetation and environment have been related to their gradients. The results were discussed and related, above all, to the ecological properties of the constituent species as well as to pond management.