Articles by Taxonomic Group

Excretion into the environment of dissolved organic matter produced during photosynthesis is a characteristic phenomenon for several species of aquatic macrophytes (Wetzel 1969 a, b). Several of these substances are imbibed by heterotrophic microorganisms and may also inhibit the growth of other hydrobionts. An examination of the interactions between macrophytes and aquatic fungi showed that during the growing period (spring, summer and autumn), relationships between these organisms change. At the beginning of the growth period, the number of species of aquatic fungi rose in the presence eight macrophytes; during the summer there was a decrease in the number of fungi observed; while in the autumn (end of the growing season) there was an inhibitive influence of macrophytes on the growth of aquatic fungi, which was higher in eutrophic water. This inhibitive influence depends probably on the storage of any secondary compounds during aging of several macrophytes, which inhibit the growth of several species of fungi and fungus-like organisms.

Straminipilous organisms and fungus species on dead fragments of 25 taxa of wetland plants from three water bodies were investigated. A total of 219 fungal taxa, including 85 straminipilous organisms and 134 fungus species were recorded. The largest number of straminipilous organisms and fungus species occurred on fragments of Lathyrus palustre and Rorippa amphibia (45 and 44 species respectively), the fewest on Calla palustris (20). The most common species were Chytridium xylophilum (on 23 plants), Pythium rostratum (on 15), Pithomyces obscuriseptatus (on all plants), Trinacrium subtile (on 17) and Titaea (Tetracladium) maxilliformis (on 16). The larger numbers of species were recorded in running water (Jaroszówka Spring, Supraśl River, 124 and 122 respectively), with fewest (106) in stagnant water at Dojlidy Pond. Thirty-one taxa were recorded for the first time from Poland.

The authors investigated aquatic fungi and chromistan organisms growing on the dead specimens of 11 species of free-floating plants in the water from three limnological and trophical different water bodies (spring, river and pond). On the specimens investigated plants in the water of water bodies of north-eastern Poland they identified 129 species including 57 chromistan organisms and 72 fungus species. The most common taxa were Aphanomyces laevis, Thraustotheca clavata, Pythium inflatum, P. rostratum, Anguillospora filiformis, A. pseudolongissima, Angulospora aquatica, Heliscus submersus, Lemonniera aquatica, Pithomyces obscuriseptatus, Tetracladium marchalianum, Tricellula aquatica. Most fungus species were observed on the specimens of Utricularia minor, U. vulgaris (each 36) and Hydrocharis morsus-ranae (34), fewest on Lemna gibba (22), Aldrowanda vesiculosa and Lemna minor (each 23). The most taxa were growing in the water from River Supraśl (64), the fewest in the water from Spring Jaroszówka (55). A number of chromistan organisms and fungus species (2 and 11 respectively) appeared new to Polish waters.