TROPHIC STATE INDEXES AND PHYTOPLANKTON IN THE TROPHIC STATUS ASSESSMENT OF WATERS OF A SMALL RETENTION RESERVOIR AT AN EARLY STAGE OF OPERATION

This paper will focus on determining the trophic status of the two basins of the Niwa Reservoir - Niwa I and Niwa II (Sawin commune, Lubelskie Province, SE Poland) at the sixth year of operation, by using partial TSI indexes – TSI(SD), TSI(TP), TSI(chl-a), as well as qualitative and quantitative structures of phytoplankton. As a supplementary, index TSI(TOC) was employed [Dunalska 2011]. We show that the phytoplankton abundance, as well as TSI(chl-a) and TSI(TP) were relatively low and typical for mesotrophic waters (with the exception of July TSI(TP) values for the Niwa II basin), although the evaluation of trophy based on other partial TSI indexes – TSI(SD), TSI(TOC) pointed to a eutrophic or even a hypertrophic water characteristic. The obtained results were discussed in detail and referenced to other, non-nutrient related trophy factors: morphometric features and geology of the basins, as well as the physicochemical properties of its water

(Ehr.) Diesing bloom formation in nine lakes of Polesie region (Central–Eastern Poland)

Using data from nine lakes, sampled between 2002 and 2010, as well as literature we have analysed blooms of Gonyostomum semen (Ehr.) Diesing in a new spreading area (Polesie region, Central–Eastern Poland). We tried to determine habitat suitability for high biomass of the species, including both physicochemical and morphometric features. High biomass of Gonyostomum (>1.4 mg.L−1) was found in three groups of coloured water bodies: (a) very small (<0.002 km2) peat pits with low pH values and mineral content; (b) larger ponds with neutral pH values and intermediate conductivity; (c) natural lakes with intermediate parameters in terms of area, pH and mineral content. There were no statistical differences regarding the values of the species biomass among the groups of lakes. Gonyostomum biomass was closely positively correlated with water colour, whereas it was weakly negatively correlated with lake area and depth. The results show that G. semen in a new spreading area bloomed in a broad spectrum of freshwater habitats

To What Degree Can the Specifics of Occurrence of Glacial Relic Betula humilis Schrank Be an Indicator of Habitat Conditions of Moderate Climate Peatlands?

Anthropogenic transformations of habitat conditions in moderate climate peatlands frequently cause a decrease in the number of sites of occurrence and the size of the population of many valuable plant species, including the boreal relic Betula humilis. The objective of this paper was an attempt to relate the specifics of the occurrence of the glacial relic Betula humilis in the peatlands of Central-Eastern Poland, which developed under moderate climate conditions, to the conditions of the natural environment identified through research into the physical and chemical parameters of the groundwater, as well as botanical research into its habitat. The study results confirm that shrub birch has a broad range of ecological tolerance to the majority of the studied factors and can therefore be an indicator of habitat transformation. Important environmental factors affecting its abundance are water relations and the contribution of calcium hydroxide and phosphorus fractions. A condition favouring the proper functioning of individuals of the studied species is TP values lower than other obtained values, in the following range: 0.08&ndash;0.32; P-PO4: 0.1; TN: 2.2&ndash;21.2; N-NH4: 0.1&ndash;0.46; DOC: 24.6&ndash;55.9 (mg&middot;dm&minus;3), as well as higher than average pH values, in the following range: 5.34&ndash;5.95; Ca: 5.67&ndash;28.1; Mg: 0.56&ndash;2.41 (mg&middot;dm&minus;3) and EC: 72.1&ndash;142.3 (&micro;S&middot;cm&minus;1)

Selenium-induced improvements in the ornamental value and salt stress resistance of Plectranthus scutellarioides (L.) R. Br.

Ornamental plants growing in urban areas are often exposed to salt stress that negatively affects their decorative value. Enhancement of their salt resistance to retain a high decorative value despite salt stress has therefore high practical importance. In our study, the exposure of Plectranthus scutellarioides (L.) R. Br. to NaCl-induced moderate (40 mM) or severe salt stress (80 mM) resulted in a number of stress responses including reduced growth parameters, decreased concentration of photosynthetic pigments, and an increase in the accumulation of anthocyanins and free proline. These changes were partially compensated for by the application of selenium (5 µM as Na2SeO4) to the growth medium. However, the beneficial effect of selenium on the growth and physiological parameters of P. scutellarioides was manifested only at the moderate level of salt stress. Under the severe salt stress, the application of selenium was not able to alleviate the phytotoxic effect of NaCl