Botanica Lithuanica, Volume 9, Number 4

2003 m.

The contents of sugars in cowberry (Vaccinium vitis-idaea L.) fruits were investigated considering their ripening degree and growth conditions. It was revealed that fructose made up the biggest part of sugars in berries, while the content of glucose was somewhat less. The content of saccharose was significantly less than those of fructose and glucose. With the ripening of berries, the amount of fructose and glucose as well as the total amount of sugars increased about ten times. The total contents of sugars and their composition in over-ripe berries changed insignificantly. Differences in sugar contents of berries from different habitats were not big and significantly less than those between different years.

Keywords: cowberry, ripening degree, sugar accumulation, fructose, glucose, saccharose, berry, growth conditions.

Distribution of Carex juncella (Fr.) Th. Fr. in Lithuania is analysed on the basis of references, herbarium and field investigation data. Conditions of C. juncella habitats and dependence of the state of its coenopopulations upon habitat conditions are discussed. Floristic composition, syntaxonomical status, and discussion on the position of communities with C. juncella in the hierarchic system of syntaxa are presented.

Keywords: Carex juncella, Cyperaceae, distribution, habitats, communities, Caricetum juncellae, Lithuania.

Qualitative and quantitative analysis of carbohydrates is an important indicator of the xylem quality, on which the possibilities of utilisation of plant raw material depend. Results of the investigation on quantity of carbohydrates in the xylem of certain willow (Salix) species, their hybrids, and clones, cultivated under unified conditions, are presented in this paper. Willows characterised by the largest quantity of cellulose, hemicellulose, and lignin are specified. Dependence of the quantity of carbohydrates in raw material upon species, hybrids, and clones, as well as the age of plants is analysed. Importance of carbohydrates for the quality of xylem is discussed.

Keywords: Salix, Salicaceae, cellulose, hemicellulose, lignin.

At present data on significant transformation processes taking place in sown meadow communities undergoing naturalization on various types of the Lithuanian natural landscape are still missing. The discussed data could be supplemented with a thorough investigation on sown meadow grassland structure, vascular plant species composition and aboveground phytomass. It would reveal changes in communities, naturalization peculiarities and prospects of grassland cultivation. The research data (2001–2002) on sown mesophillous grasslands (10–11 years of running) characteristic by their composition to the Central Lithuanian Plain region are presented.

Keywords: sown meadow, community, structure, diversity, aboveground phytomass, economic yield, agricultural landscape, Lithuania.

Three Sorbus cultivars (‘Cooper Glow’, ‘Coral Beauty’, and ‘Pink Green’) and five forms of Sorbus aucuparia (ŠA-20, ŠA-36, ŠA-39, T14-7, and T14-9) were investigated. At harvest time in September the weight of 100 fruits of Sorbus cultivars was 34.4–38.9 g and of Sorbus aucuparia forms – 39.1–93.3 g. The content of pectins and dietary fibers in fruits gradually decreased during the ripening period, and in September it was the lowest in 100 g of fresh fruits. The content of these substances at harvest time was about 4 g/100 g in average of fresh fruits. The content of sour matters was 0.4 % in average.

Keywords: pectin, dietary fibers, sour matters, fruit weight, dynamics.

Epiphytic algae of five lakes with different trophic level collected from four aquatic plant species were investigated. Three species of filamentous and one species of coccous cyanobacteria new to Lithuanian water basins are reported. Descriptions of morphological features and drawings of Tolypothrix tenuis, T. lanata, Hapalosiphon fontinalis, and Aphanocapsa sp. are presented. Discussion and comments on the distribution of species in epiphyton communities are given.

Keywords: Tolypothrix, Hapalosiphon, Aphanocapsa, filamentous cyanobacteria, epiphyton, lakes, Lithuania.

New localities of Pycnora sorophora in North-East Poland and in Lithuania are reported. Distribution, morphology, and ecology of the species in both countries are discussed. Geographical distribution of the taxon is still poorly known in the studied territory as well as in close-laying areas.

Keywords: Pycnora sorophora, lichens, Poland, Lithuania.

The paper presents five lichen species recorded for the first time in Lithuania: Bactrospora dryina, Lecanora compallens, Lecidella subviridis, Lepraria borealis, and Sclerophora peronella. Short characteristic of the species, their ecological preferences, geographical distribution, and map of localities in Lithuania are provided.

Keywords: Bactrospora, Lecanora, Lecidella, Lepraria, Sclerophora, lichens, Lithuania.

The dynamics of stagonospora blotch (causal agent Stagonospora nodorum (Berk.) Castellani et E. G. Germano) spreading on the varieties of spring triticale ‘Gabo’, ‘Wanad’, and ‘Cargo’ was studied in 2000 and 2001 in Pajūris lowland of Lithuania. Expansion of the stagonospora blotch was determined by meteorological conditions, especially by the amount of precipitation. Under weather conditions unfavourable for the spreading of disease ‘Wanad’ appeared to be most resistant to S. nodorum, while ‘Gabo’ was most resistant to the pathogen when weather conditions were favourable for S. nodorum.

Keywords: triticale, cultivars, Stagonospora nodorum, meteorological conditions.

The study was performed with two biological products: Mycostop (Streptomyces griseoviridis K61), to control Pythium root rot agents in gerbera, and Fitoverm (Streptomyces avermictilis BHNNCXM-54), to control Tetranychus urticae and Thrips tabaci on cucumber. Biofungicide Mycostop was efficient against root rot of greenhouse ornamentals and vegetables and did not differ in efficiency when compared with fungicide Previcur 607 SL (propamocarb hydrochloride). Composition of micromycete species, their spreading in greenhouse substrate, reaction to Previcur, and interaction with antagonistic microorganisms Sterptomyces griseoviridis were studied. Previcur most efficiently reduced and inhibited the development and spreading of micromycetes in the substrate. Mycostop suppressed the development of many pathogenic fungi species. Both lowest (0.2 %) and highest (1.0 %) rates of Fitoverm were more effective against mites. The death rate of thrips was high when 0.5–1.0 % emulsions were used.

Keywords: micromycetes, gerbera, cucumber, Streptomyces griseoviridis, Streptomyces avermictilis, Tetranychus urticae, Thrips tabaci.