Botanica Lithuanica, Volume 1, Number 1

1995 m.

Localization of mucilage cells and mucilage indications in the Lithuanian angiosperms was studied with the purpose of estimating their diagnostic significance. 313 species belonging to 75 families were investigated. Mucilages were not found in plants of 86 investigated species. The mucilage indications were observed in the more primitive species of Magnoliopsida and Liliopsida. The mucilage cells were observed in the more developed taxa of Magnoliopsida. The investigations of genus Viola have shown that the amount of mucilage cells is related to the ecological conditions of the plant habitat.

Keywords: water soluble polysaccharides, mucilage cells, mucilage indications, Magnoliopsida, Lithuania.

Distribution of Impatiens glandulifera in Lithuania is analysed. This cultivated and recently naturalized species is more frequent in the southern and eastern parts of the territory. Notes on biology of I. Glandulifera are presented. Communiteis in which this species is naturalized are described.

Keywords: Impatiens glandulifera, distribution, biology, naturalization, phytocenoses with Impatiens glandulifera, Lithuania.

The phytoplankton of the river Merkys basin (South East of Lithuania) was investigation in 1976–1994. Totally 148 algae species and 14 varieties were recorded in the investigated streams. The diatoms (Bacillariophycaea) and green algae (Chlorophyceae) dominated in the studied phytoplankton, respectively they comprised 52 % and 29 % of the recorded taxa. The number of true planttonic diatoms were rather small: most of the suspended algae were tychoplanktonic. The green algae were dominated by small planktonic Chlorococcales.

Variations in seasonal succesion were closely related to the stream order. In the first and second order stream diatoms were dominant during the year. In the third and fourth order streams a typical alteration of diatoms (spring, autumn) and green algae (summer) occerred.

Keywords: phytoplankton, species composition, seasonal succesion, streams.

The research tests of late summer phytoplankton regarding their seasonal succesion were conducted using experimental models with water of different eutrophic conditions. This allowed to carry out an evaluation of the following changes during the succesion: composition of algae, percentage abundance of algae, biomass of phytoplankton, photosynthesis and respiration of phytoplankton, amount of saprophytic bacteria, dynamic of group B vitamins both in water and phytoplankton biomass. Changes of phytoplanktocenosis coincided mainly with changes in the content of group B vitamins in water.

Due to a large amount of available research data, this paper is divided into several parts to analyze the test results of the succesion of late summer and spring phytoplankton, and the influence of different vitamins on the succesion of phytoplankton.

Keywords: succesion of phytoplankton, vitamins in succesion of phytoplankton.

Investigations on dynamics of the biological productivity of 17 year old cultured meadow communities are presented. The experiments were carried out in the Davila ecological landscape station (Utena region, East Lithuania) in a drained cultivated lowtype peat-bog on diverse humidity terraces along the pond. On the basis of the binomial correlation data analysis meadow bioproductivity dependence upon meteorological factors, biological characteristics of grass species and changes of specific composition was determined.

Keywords: cultural meadow, bioproductivity, aboveground phytomass, underground phytomass, dynamics, binomial correlation, meteorological factors.

Two species of the genus Fellhanera Vezda are reported as new to Lithuania: F. bouteillei (Desm.) Vezda and F. subtilis (Vezda) Diederich & Sérus. Both species were collected from Vaccinium myrtillus stems, F. subtilis – from twigs and needles of Picea abies in addition, in humid old Picea abies and P. abies – Pinus sylvestris stands. Lichen species associated with F. subtilis were: Hypogymnia physodes (L.) Nyl., H. tubulosa (Schaer.) Hav., Cetraria chlorophylla (Willd.) Vain. on Picea abies twigs and needles, Dimerella pineti (Ach.) Vezda, Bacidia chloroticula (Nyl.) A. L. Sm. on Vaccinium myrtillus. The latter lichen species is reported for the first time for Lithuania as well.

Keywords: Foliicolous lichens, Fellhanera, Bacidia chloroticula, Lithuania.

The first locality of Plagiothesium undulatum (Hedw.) Schimp. in Lithuania is desrcibed. This oceanic species was found in the forest Šiurinė (Tauragė district) in Picea abies forest. The Lithuanian locality of P. undulatum gives an additional information about this species range and anables the correction of its boundaries.

Keywords: mosses, Plagiothesium undulatum, Lithuania, geographical range.