Abstract Samples of Limecola balthica with normal and deformed shells were collected from ten sites throughout the Gulf of Riga. Genetic diversity was evaluated by the retrotransposon-based iPBS method. Samples had close mutual genetic distances, which showed that all of them belong to one wider population of the Gulf of Rīga. No direct relationship between the activity of retrotransposons and deformation of shells was found.
Abstract Sprouts of diploid red clover 'Stendes Agrais' were treated with 0.2% colchicine solution. The ploidy level of plants was detected by flow cytometry. Most of the treated plants were mixoploids and sterile. From progenies of fertile plants, mixoploids were selected that had a proportion of tetraploid cells higher than 60%. In the next generation, stable tetraploid plants were selected, and 49 lines were included in the breeding process.
Abstract The paper presents the results of combined effects of an extremely low frequency electromagnetic field (50 Hz) (ELF EMF) and SiO2 nanoparticles on fluorescence of plant gametic cells (immature microspores). The data were recorded by a BD FACSJazz® cell sorter after cell irradiation by blue laser (488 nm). A significant difference of fluorescence was observed between gametic cells after 1 hour incubation in suspension of SiO2 nanoparticles and the control gametic cells. It was observed that fluorescence intensity of gametic cell was higher with ELF EMF treatment in comparison to control cells, but it was statistically significant only for cells treated with electromagnetic radiation field with density 100 μT (ρ < 0.01) and 400 μT (ρ < 0.01). A different effect of ELF EMF were observed in cells incubated in SiO2 nanoparticle suspension; interaction of the factors resulted in lower cell fluorescence in comparison to control cells. The present study showed that SiO2 nanoparticles may be a source of oxidative stress, but jointly with 50 Hz electromagnetic field they can serve as an efficient antioxidant
Abstract Assessment of the effect of urbanisation on biodiversity and ecological impact studies are focused on plants, birds, terrestrial arthropods, and relatively few studies have been on aquatic organisms. The aim of this study was to investigate the microbial food web components as potential indicators of the trophic state of two small natural lakes (Gaiļezers, Bābelītis), two artificial lakes or reservoirs (created after excavation activities before 20 years) and the Gulf of Riga seaside Vecāķi beach (littoral), all of which are located in the city of Riga or close to it. Analysis of samples was conducted from April til October 2014 by epifluorescense microscopy for pico and nanoplankton (DAPI staining), and by inverted microscopy (Lugol's fixation) for planktonic ciliates. SYBER green for DNS staining was used to examine population structure in a qualitative way by the cytometre Facs Jazz FCM. The obtained results illustrate that the studied aquatic ecosystems have different impact of eutrophication: the mean seasonal trophic status index value was higher in Lake Bābelītis (5.22) than in Lake Gaiļezers (4.57), Saurieši reservoir (4.76) and Bolderāja reservoir (4.22). In Bolderāja reservoir, picoplankton density reached maximum development (192 thous.cells/mL). The nanoplankton consists mainly of autotrophic flagellates, and their abundance was positively related with increasing size structure groups. During seasonal succession stages, ciliates of the size group less than 30 μ are well presented and could be analysed by flow cytometry together with pico and nanoplankton. Bolderāja reservoir could serve as reference site against lakes Gaiļezers and Bābelītis due to less eutrophication impact.
Accessions with no germinating seeds are a common problem in plant gene banks and research institutions. Our goal was to elaborate and apply an in vitro method of germination and multiplication of old aged seeds of red and alsike clover and alfalfa. Eighteen clover and five alfalfa accessions were used for germination in vitro. Most of the accessions had produced seeds more than 20 years ago and the seeds did not germinate in soil. Seed pre-treatment with different concentrations of potassium permanganate, as well as addition of phytohormones, AgNO3 and activated carbon to germinating media were tested. Plantlets for all germinated accessions were obtained, even in the case when seeds were 44-year-old (alfalfa). Germination rate in vitro not always correlated with seed age and ranged from 2 to 72%. Pre-treatment with potassium permanganate was effective both for seeds sterilisation and germination stimulation. Most germinated seeds formed phenotypically normal seedlings with all organs. In vitro multiplication of obtained clover plants was performed. Best results were achieved by micropropagation of stem segments approximately 2 mm in length. Number of finally obtained plants depended not only on seed germination ability, but also on micropropagation ability in relation to genotype, and on acclimatization success in soil after in vitro cultivation
Abstract Mute swan Cygnus olor is the most abundant breeding swan species in Rīga and Latvia. Since manmade habitats are the preferred breeding habitats of this species - Cygnus olor is of particular interest in studies of urban biodiversity. The latest records show that 30-40 pairs breed annually in Rīga, 400-700 individuals migrate through the area, and 120-150 individuals stay over winter. The goal of our study was to determine the genetic variation of the mute swan population in Rīga. Blood samples were collected from 47 individual birds found in different sites in Rīga or elsewhere in Latvia. The universal retrotransposon based iPBS markers were used to estimate diversity. Three primers (2076, 2080, and 2415) amplified 64 DNA fragments; of these 18 (28%) were polymorphic. The average diversity index based on polymorphic markers for the studied individuals was 0.425. All individuals, with the exception of two pairs of individuals, could be separated by means of these markers. The grouping of individuals was not be associated with their sampling location, gender and age. The genetic diversity indexes were compared between these groups. The breeding individuals (including their cygnets) had bands not showing variation among breeding birds as compared to the not breeding ones.
Abstract White clover (Trifolium repens L.) is well represented in the urban environment and wide areas. The goal of this study was to compare the genetic features and to determine the genetic distances and similarities between some populations of white clover using iPBS (inter primer binding sites) technique in a retrotransposon-based method in samples from ecologically different areas in Latvia. Comparisons were made between three plant groups: urban environment (different areas in Rīga), Latvian countryside territory (four different localities), and the commercial variety 'Daile'. The Shannon diversity index was not high (0.2974 for Rīga, 0.3079 in countryside territories, and 0.3367 for the variety 'Daile'), but the polymorphic bands present in all evaluated plant sets were higher than 89%. Using principal coordinates analysis the white clover formed three clusters. One cluster included plants from the variety 'Daile'. The plants from Rīga urban area and different sites of Latvia formed two clusters.
Abstract The unique biological properties of amber are well known. Amber particles that penetrate into the cellular matrix can potentially be used as markers of plant cell biological activity by identification of living cells in flow cytometry. However, there have been no studies on effect of amber particles on plant cells. The aim of this study was to determine effect of amber nano- and micro- (5 nm-3 μm) particles on somatic and gametic cells and to assess the possibility to use amber particles as alive plant cells markers. To reach the aim, fluorescence of cells was determined in the presence of amber particles, and amber components - spirit of amber and sodium succinate dibasic hexahydrate. Cell fluorescence was measured using a BD FACSJazz® cell sorter for several plants species (Argyranthemum frutescens, Cyclamen persicum, Hordeum vulgare and Linum usitatissimum) with and without treatment of amber. Differences between a control cell group (without amber treatment) and treated cell group with amber particles depended on plant species. The presence of amber components (alcohol soluble amber fraction and sodium succinate) in cultivation media mostly had no influence on cell fluorescence. The study showed that amber particles (size 5 nm-3 μm) can be used as living plant cell markers, as the presence of amber particles in plant cell cultivation media resulted in substantially increased plant cell fluorescence in all investigated species, and there was no detrimental effect of amber particles on plant cells.
Abstract According to the Global Strategy for Plant Conservation, 75% of endangered species should be preserved in ex situ collections till 2020. The genus Liparis has a lot of recognised taxons, but only one species, Liparis loeselii (L.) Rich., grows in Europe. L. loeselii is a rare and endangered orchid species occurring in Europe. In Latvia L. loeselii is classified as the third category of endangered and protected species. To develop the best conservation strategy, the knowledge concerning the genetic differences of protected plants in a particular area is crucial. For this purpose, the genetic diversity of L. loeselii populations from different Latvian habitats was tested. The inter-retrotransposon amplified polymorphism method (iPBS) was used for population genetic diversity evolution. In total, 54 accessions from nine habitats were collected and analysed. L. loeselii leaves have a high content of phenols that reduce the quality of extracted DNA. It was found that the percentage of polymorph loci varied among the populations of L. loeselii growing in different habitats; some of the populations were genetically homogeneous. The genetic diversity levels of L. loeselii populations are related with the population age and the growing conditions.
Abstract Our goal was to improve the method of obtaining double haploids (DH) by anther culture from Latvian breeding material for several agriculturally important cereals in Latvia: barley, spring and winter wheat. Hybrids from Latvian breeders were initial material. It was found that copper (2.5 mg/l) added to barley anther pre-treatment media and to both barley (C3) and wheat (liquid AMC) induction media, resulted in a higher percentage of green plants-regenerants. In general, the winter wheat hybrids exhibited lower embryogenesis than spring wheat hybrids. Obtaining a large number of DH lines from barley and wheat hybrids with unknown androgenesis response can be organized in two stages: first - selection from breeding initial material hybrids responsive in anther culture, which enables production of green plants-regenerants, and second - production of DH lines in a large scale from selected hybrids.
Frequency of callusogenesis, type and capacity of regeneration, cell ploidy, DNA methylation level, histological features, autofluorescence and photobleaching effects were studied in flax calli grown on medium supplemented with different concentrations of carbon (C) nanoparticles. The presence of carbon nanoparticles on medium decreased the percentage calli formation. Detailed histological study led to better understanding of changes in calli caused by nanoparticles. Ploidy variation in calli cells significantly depended on carbon nanoparticle concentration in the medium. Different types of calli regeneration associated with different C nanoparticles concentration in medium were observed: somatic embryogenesis (direct or indirect) or organogenesis. C nanoparticle dose-dependent DNA hypermethylation in flax calli cells were found. Increased repair ability during laser irradiation was found in calli grown on medium with carbon nanoparticles
