Dace Grauda - Academia.edu (original) (raw)
Papers by Dace Grauda
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
We have carried out restoring of some Latvian alfalfa genetic resources from seeds of accessions ... more We have carried out restoring of some Latvian alfalfa genetic resources from seeds of accessions that did not germinate in soil at all. Two of them were repatriated from the N. Vavilov All-Russian Institute of Plant Industry (multiplied more than 40 years ago) and three from the Research Institute of Agriculture (Latvia) (multiplied 15-20 years ago). For germination of old seeds we used early elaborated in vitro culture conditions. Germination rate ranged 2-60%, depending from the genotype and seeds storage conditions. Plantlets with well developed roots and 2-3 leaves were planted in the substrate in small pots and grown in a greenhouse about a month, then replanted in the soil in field conditions and grown till the maturity. Restored accessions are available now for evaluation and involving in the alfalfa breeding programs.
III International Symposium on Acclimatization and Establishment of Micropropagated Plants, 2009
The aim of investigation was to develop a tissue culture approach that includes combination of a ... more The aim of investigation was to develop a tissue culture approach that includes combination of a seed sterilisation method, the use of silver nitrate and antioxidants during different stages of calli induction, and shoot regeneration from flax accessions with tow regeneration capacity. AII used flax varieties ('Vega 2'r'Lirina', and 'Rigaer B') were excellent for calli culture formation (l00oh of explants form calli). Addition of AgNO3 to the seed germination medium promoted calli culture formation. Development of plants-regenerants was depended on the used 2r4-D concentrafion in calli inducfion medium, antioxidant, explant fype (stem segments, leaves) and genotype but was not related to the calli weight. Antioxidants increased calli regenerafion capacity. Plants-regenerants were obtained only from stem calli.
Elite material of the Latvian red clover variety ‘Agra was included ˙ in the experiment for obser... more Elite material of the Latvian red clover variety ‘Agra was included ˙ in the experiment for observation of calli formation and their regeneration. Leaves, stem segments and leaf petiole segments were used as explants. Different frequency of calli formation was observed depending from the explants type. Most frequently calli were formed on leaf segments. The size of calli varied depending fromthe size of explants andwas, in general, independent from the type of explant. The largest calli were developed from the smaller (2 mm) leaf petiole segments. Different types of the calli regeneration were observed. Organogenesis was characteristic feature of regeneration from calli induced on stem segments, rhysogenesis – on leaf segments. Calli induced on leaf petiole segments formed somatic embryos and their posterior regeneration in the whole plant was observed. Embryogenesis was obtained from 12.5% of calli induced on leaf petiole segments.
By using somaclonal variation it is possible to obtain plant breeding source material with modifi... more By using somaclonal variation it is possible to obtain plant breeding source material with modified agronomical traits. In flax is known somaclonal variation in resistance to biotic and abiotic stress, plant height, number of seeds in a vessel and number of seeds. The best for obtaining somaclonal variation is calli culture. This study was carried out to determine the best method of obtaining oil flax calli culture. Different parts of plants were used as explants (stem segments, leaves, root segments). For calli culture establishment, MS basal medium with 2 mg l-1 2,4-D was used. For inducing shoot formation, MS medium supplemented with 0.2 mg l-1 IAA or 1 mg L-1 BAP and MS medium without phytohormones were used. As a carbohydrates source, 30 g l-1 of sucrose was used in all mediums. For shoots rooting, MS medium with 0,1 mg l-1 IAA and 1 g l-1 AgNO3 and 10 g l-1 sucrose were used. Development of root-like structures and regeneration zones was dependent on both the used medium and e...
In 1990ies, new spring wheat breeding programme was established at the State Stende Cereals Breed... more In 1990ies, new spring wheat breeding programme was established at the State Stende Cereals Breeding Institute with the goal to create new varieties with the high grain yield and quality, conforming industry requirements, as well with the resistance to lodging and main diseases. Traditional breeding methods are dominant in cereals breeding till nowadays. Nevertheless, traditional breeding methods are slow and could take even 15 years till the developing of a new variety. Methods of biotechnology, like double haploids (DH) and molecular marker assisted selection could highly contribute to improving efficiency and to speeding up the breeding process. The application of the spring wheat breeding programme started with renovation and evolution of the genetic resources usable as an initial breeding material in Latvian conditions. DH technology and molecular marker methods were used in appropriate breeding stages. The protocol of DH lines obtaining from spring wheat anther culture was mod...
Repatriated flax accessions of Latvian origin from the N. I. Vavilov Institute of Plant Industry ... more Repatriated flax accessions of Latvian origin from the N. I. Vavilov Institute of Plant Industry (Russia), the Flax Research Institute (Russia) and the Institute of Plant Genetics and Crop Plant Research (Germany), and best flax lines breed in the Agricultural Science Centre of Latgale were investigated. Several qualitative and quantitative traits, such as technical plant height, number of seed vessels, logging resistance, vegetation period, yield of straws and seeds, bast fibre, oil content and quality were evaluated. Results of tree year field trials were summarized. Some local genotypes and lines were better than the standard fibre flax variety ‘Vega-2’ and the standard oil flax variety ‘Lirina’ in several agriculturally important traits. For intensification of the breeding process we were looking for the possibility of using biotechnology methods for obtaining additional flax breeding source material. After cultivation in calli culture regenerated plants could perform to a highe...
Studies of molecular markers provide an opportunity to explore some genetic characteristics of pa... more Studies of molecular markers provide an opportunity to explore some genetic characteristics of particular populations, such as the number of polymorphic loci, frequencies of alleles, set of unique alleles, and, on this base, similarity and distances between populations. The aim of this study was to describe genetic variation in Lithuanian perch populations using one of the most popular molecular marker system – IRAP (Inter-Retrotransposon Amplified Polymorphism). The specimens were collected from four Lithuanian water reservoirs: three lakes (Drūkšiai, Plateliai, Metelys) and river Nemuna. DNA was extracted from muscle tissues of 20 individuals from the each population by innuPREP DNA Mini Kit (Analytik Jena). DNA samples were amplified by PCR with three previously selected specific retrotransposon-based primers and electrophoresed on agarose gel. In total, 128 loci were found, 80 (62%) of them were polymorphic. The numbers of polymorphic loci within each population varied between 2...
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
Plant calli culture could be used as a source of genetic changes (somaclonal variation). There ar... more Plant calli culture could be used as a source of genetic changes (somaclonal variation). There are known several flax varieties, bred on the basis of somaclonal variation, with improved resistance to biotic and abiotic stresses, plant height, seed yield and other traits. This method is useful for obtaining the new initial material for flax breeding, including for intensification of breeding for organic farming. Goal of the study was to obtain plants-regenerants from the calli culture of the fibre flax variety 'Vega 2' and to evaluate their agronomical traits and resistance to powdery mildew. For obtaining plants-regenerants was used early elaborated protocol of somatic calli cultivation. Agronomically important traits, such as total and technical plant height, number of seed vessels, number of seeds in a seed vessel, and resistance to diseases were evaluated. Most of somaclonal families had higher total and technical plant height in comparison with the initial variety 'Vega 2'. In the opposite, number of seed vessels and number of seeds in a seed vessel had a tendency to decrease. It was concluded that even changes in not desirable direction may be recognised as an indirect indicator of the rather high level of induced somaclonal variation, which can occurred also in traits, which were not evaluated during this experiment, therefore there is a potential to exploit flax somaclonal variation in applied breeding programs as an additional source of variability.
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
This study aimed at investigating the growth conditions, genetic composition and variability of C... more This study aimed at investigating the growth conditions, genetic composition and variability of Cypripedium calceolus L. populations in Latvia. In order to ensure an appropriate level of protection of a species, knowledge of its habitat diversity and genetic diversity is crucial. The species in question occurs in different habitats on mesic soils, in deciduous broadleaved, mixed and coniferous forests. The genetic composition and variability of populations might define the relative differences in the environmental response of C. calceolus. To address these aspects, a novel, recently developed universal method of DNA fingerprinting was applied for the first time for the Cypripedium genus. 22 specific PCR primers were tested to select those which reveal the highest level of genetic polymorphism. The three selected primers (yielding 40 loci) were applied to estimate the genetic variability among the plants within a site and between different sites. A rather high genetic diversity withi...
For the study, 16 lily genotypes were chosen, including fi ve Latvian varieties well adapted to t... more For the study, 16 lily genotypes were chosen, including fi ve Latvian varieties well adapted to the Latvian climate. The genotypes belong to three different sections and two intersection hybrids. Ovaries were cut in the 5 th , 10 th , 14 th , 20 th and 23 rd days after pollination and cultured on Murashige and Skoog basal medium
We have carried out restoring of some Latvian alfalfa genetic resources from seeds of accessions ... more We have carried out restoring of some Latvian alfalfa genetic resources from seeds of accessions that did not germinate in soil at all. Two of them were repatriated from the N. Vavilov All-Russian Institute of Plant Industry (multiplied more than 40 years ago) and three from the Research Institute of Agriculture (Latvia) (multiplied 15-20 years ago). For germination of old
The glycoalkaloid content in potato tubers can be influenced by several factors: variety, weather... more The glycoalkaloid content in potato tubers can be influenced by several factors: variety, weather, storage environment, maturity, damage, temperature and exposure to light. Potato varieties vary with regard to their inherited total glycoalkaloid (TGA) content. The problem in the practical use of most TGA detection methods is that they are money and time consuming. The aims of the investigation were adaptation of a rapid and rather cheap method and evaluation of TGA content of varieties included in Latvia potato genetic resources. The used method was based on three earlier elaborated protocols of different authors. 31 varieties of Latvian potato genetic resources were examined for TGA content for two years, 10 of them for three years. TGA content depending on the variety ranged from 2 till 27 mg 100 g -1 fresh weight, the variance between genotypes was high. The significant genotype influence on TGA content was established. The influence of growing conditions on TGA content was not s...
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
Molecular markers based on retrotransposons possibility of integration into genomes of many organ... more Molecular markers based on retrotransposons possibility of integration into genomes of many organisms are commonly used for genetic analysis of different species. The aim of this study was to test the possibility of use those markers in perch and detect the genetic diversity of populations of two lakes of the Latgale region of Latvia: Cirišs and Sventes. The distance between the lakes is nearly 60 km, they belong to the same Daugava River basin but are different from the ecological point of view. Forty-two blood samples of Perca fluviatilis were collected altogether. Extracted DNA was analyzed using inter-PBS amplification technique with specifically selected retrotransposonbased primers and agarose gel electrophoresis. Data of genetic diversity of lakes were calculated by POPGENE and NTSYS software. In total, 127 loci were found in two populations, 81 of them were polymorphic. In spite of the rather small distance between lakes Cirišs and Sventes, several differences in genetic variation of populations of two lakes were found. For example, the number of polymorphic loci in samples from Lake Sventes was 61, but only 47 from Lake Cirišs. A unique allele was found in Lake Sventes. Genetic similarity and distance between populations of lakes Cirišs and Sventes was 0.9288 and 0.0739, respectively. The results proved that molecular markers based on retrotransposons PBS regions can be very useful to test the genetic diversity of fish populations.
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences, 2013
Audu kultûras apstâkïos panâkta tâdu vecu âboliòa un lucernas sçklu izdîgðana, kuriem bija zaudçt... more Audu kultûras apstâkïos panâkta tâdu vecu âboliòa un lucernas sçklu izdîgðana, kuriem bija zaudçta dîgtspçja parastos apstâkïos. Iegûti fertîli augi, kuri papildina pieejamos ìençtiskos resursus attiecîgo kultûraugu selekcijas vajadzîbai.
Urban Forestry & Urban Greening, 2015
ABSTRACT White clover (Trifolium repens L.) is a commonly cultivated legume with good ground cove... more ABSTRACT White clover (Trifolium repens L.) is a commonly cultivated legume with good ground cover potential often used with companion grass species in urban grassed areas. The effect of increased soil salinity on plant growth is an urgent problem in cities where NaCl is used as a de-icing material. The aim of this research was to examine the effect of different salinity levels and K supply induced responses and tolerance in the T. repens L variety ‘Daile’, a variety which is used in urban greenery. To analyze the impact of increased soil salinity and the antagonistic effect of K, the effect of gradually increasing NaCl (0; 20; 40; 60; 80; 100 mM) and K (+0; +100; +200; +300 mg/L) levels on T. repens plants was investigated in a pot experiment. Concentrations of 12 nutrients, Na and Cl were determined in the plant shoots and roots, as well as plant weight, Pv/Fm, P index (photosynthetic performance) and proline content. The results revealed that increased substrate salinity led to accumulation of both Na and Cl in tissues of T. repens and significantly reduced Mg. Na and Cl concentration in the plant shoots increased in accumulative manner, but in the roots, the concentration of both elements increased in the treatments with applied NaCl concentrations up to 60 mM. In the roots, a significant decrease of N, K, Mg, S, Mo and an increase of Na, Cl, Ca, Fe, Mn, Cu, Zn content was detected with increasing substrate salinity. Elevated soil salinity had a minor impact on the photosynthetic performance of T. repens. A significant decline in the fresh and dry biomass of the plant shoots was measured in all salinity treatments. In conditions of increasing soil salinity and K content, T. repens possessed several mechanisms of adaptive value, as well as changes in mineral nutrition. According to the obtained results, cultivation of T. repens variety ‘Daile’ in urban areas with slight or moderate salinity is possible.
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
We have carried out restoring of some Latvian alfalfa genetic resources from seeds of accessions ... more We have carried out restoring of some Latvian alfalfa genetic resources from seeds of accessions that did not germinate in soil at all. Two of them were repatriated from the N. Vavilov All-Russian Institute of Plant Industry (multiplied more than 40 years ago) and three from the Research Institute of Agriculture (Latvia) (multiplied 15-20 years ago). For germination of old seeds we used early elaborated in vitro culture conditions. Germination rate ranged 2-60%, depending from the genotype and seeds storage conditions. Plantlets with well developed roots and 2-3 leaves were planted in the substrate in small pots and grown in a greenhouse about a month, then replanted in the soil in field conditions and grown till the maturity. Restored accessions are available now for evaluation and involving in the alfalfa breeding programs.
III International Symposium on Acclimatization and Establishment of Micropropagated Plants, 2009
The aim of investigation was to develop a tissue culture approach that includes combination of a ... more The aim of investigation was to develop a tissue culture approach that includes combination of a seed sterilisation method, the use of silver nitrate and antioxidants during different stages of calli induction, and shoot regeneration from flax accessions with tow regeneration capacity. AII used flax varieties ('Vega 2'r'Lirina', and 'Rigaer B') were excellent for calli culture formation (l00oh of explants form calli). Addition of AgNO3 to the seed germination medium promoted calli culture formation. Development of plants-regenerants was depended on the used 2r4-D concentrafion in calli inducfion medium, antioxidant, explant fype (stem segments, leaves) and genotype but was not related to the calli weight. Antioxidants increased calli regenerafion capacity. Plants-regenerants were obtained only from stem calli.
Elite material of the Latvian red clover variety ‘Agra was included ˙ in the experiment for obser... more Elite material of the Latvian red clover variety ‘Agra was included ˙ in the experiment for observation of calli formation and their regeneration. Leaves, stem segments and leaf petiole segments were used as explants. Different frequency of calli formation was observed depending from the explants type. Most frequently calli were formed on leaf segments. The size of calli varied depending fromthe size of explants andwas, in general, independent from the type of explant. The largest calli were developed from the smaller (2 mm) leaf petiole segments. Different types of the calli regeneration were observed. Organogenesis was characteristic feature of regeneration from calli induced on stem segments, rhysogenesis – on leaf segments. Calli induced on leaf petiole segments formed somatic embryos and their posterior regeneration in the whole plant was observed. Embryogenesis was obtained from 12.5% of calli induced on leaf petiole segments.
By using somaclonal variation it is possible to obtain plant breeding source material with modifi... more By using somaclonal variation it is possible to obtain plant breeding source material with modified agronomical traits. In flax is known somaclonal variation in resistance to biotic and abiotic stress, plant height, number of seeds in a vessel and number of seeds. The best for obtaining somaclonal variation is calli culture. This study was carried out to determine the best method of obtaining oil flax calli culture. Different parts of plants were used as explants (stem segments, leaves, root segments). For calli culture establishment, MS basal medium with 2 mg l-1 2,4-D was used. For inducing shoot formation, MS medium supplemented with 0.2 mg l-1 IAA or 1 mg L-1 BAP and MS medium without phytohormones were used. As a carbohydrates source, 30 g l-1 of sucrose was used in all mediums. For shoots rooting, MS medium with 0,1 mg l-1 IAA and 1 g l-1 AgNO3 and 10 g l-1 sucrose were used. Development of root-like structures and regeneration zones was dependent on both the used medium and e...
In 1990ies, new spring wheat breeding programme was established at the State Stende Cereals Breed... more In 1990ies, new spring wheat breeding programme was established at the State Stende Cereals Breeding Institute with the goal to create new varieties with the high grain yield and quality, conforming industry requirements, as well with the resistance to lodging and main diseases. Traditional breeding methods are dominant in cereals breeding till nowadays. Nevertheless, traditional breeding methods are slow and could take even 15 years till the developing of a new variety. Methods of biotechnology, like double haploids (DH) and molecular marker assisted selection could highly contribute to improving efficiency and to speeding up the breeding process. The application of the spring wheat breeding programme started with renovation and evolution of the genetic resources usable as an initial breeding material in Latvian conditions. DH technology and molecular marker methods were used in appropriate breeding stages. The protocol of DH lines obtaining from spring wheat anther culture was mod...
Repatriated flax accessions of Latvian origin from the N. I. Vavilov Institute of Plant Industry ... more Repatriated flax accessions of Latvian origin from the N. I. Vavilov Institute of Plant Industry (Russia), the Flax Research Institute (Russia) and the Institute of Plant Genetics and Crop Plant Research (Germany), and best flax lines breed in the Agricultural Science Centre of Latgale were investigated. Several qualitative and quantitative traits, such as technical plant height, number of seed vessels, logging resistance, vegetation period, yield of straws and seeds, bast fibre, oil content and quality were evaluated. Results of tree year field trials were summarized. Some local genotypes and lines were better than the standard fibre flax variety ‘Vega-2’ and the standard oil flax variety ‘Lirina’ in several agriculturally important traits. For intensification of the breeding process we were looking for the possibility of using biotechnology methods for obtaining additional flax breeding source material. After cultivation in calli culture regenerated plants could perform to a highe...
Studies of molecular markers provide an opportunity to explore some genetic characteristics of pa... more Studies of molecular markers provide an opportunity to explore some genetic characteristics of particular populations, such as the number of polymorphic loci, frequencies of alleles, set of unique alleles, and, on this base, similarity and distances between populations. The aim of this study was to describe genetic variation in Lithuanian perch populations using one of the most popular molecular marker system – IRAP (Inter-Retrotransposon Amplified Polymorphism). The specimens were collected from four Lithuanian water reservoirs: three lakes (Drūkšiai, Plateliai, Metelys) and river Nemuna. DNA was extracted from muscle tissues of 20 individuals from the each population by innuPREP DNA Mini Kit (Analytik Jena). DNA samples were amplified by PCR with three previously selected specific retrotransposon-based primers and electrophoresed on agarose gel. In total, 128 loci were found, 80 (62%) of them were polymorphic. The numbers of polymorphic loci within each population varied between 2...
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
Plant calli culture could be used as a source of genetic changes (somaclonal variation). There ar... more Plant calli culture could be used as a source of genetic changes (somaclonal variation). There are known several flax varieties, bred on the basis of somaclonal variation, with improved resistance to biotic and abiotic stresses, plant height, seed yield and other traits. This method is useful for obtaining the new initial material for flax breeding, including for intensification of breeding for organic farming. Goal of the study was to obtain plants-regenerants from the calli culture of the fibre flax variety 'Vega 2' and to evaluate their agronomical traits and resistance to powdery mildew. For obtaining plants-regenerants was used early elaborated protocol of somatic calli cultivation. Agronomically important traits, such as total and technical plant height, number of seed vessels, number of seeds in a seed vessel, and resistance to diseases were evaluated. Most of somaclonal families had higher total and technical plant height in comparison with the initial variety 'Vega 2'. In the opposite, number of seed vessels and number of seeds in a seed vessel had a tendency to decrease. It was concluded that even changes in not desirable direction may be recognised as an indirect indicator of the rather high level of induced somaclonal variation, which can occurred also in traits, which were not evaluated during this experiment, therefore there is a potential to exploit flax somaclonal variation in applied breeding programs as an additional source of variability.
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
This study aimed at investigating the growth conditions, genetic composition and variability of C... more This study aimed at investigating the growth conditions, genetic composition and variability of Cypripedium calceolus L. populations in Latvia. In order to ensure an appropriate level of protection of a species, knowledge of its habitat diversity and genetic diversity is crucial. The species in question occurs in different habitats on mesic soils, in deciduous broadleaved, mixed and coniferous forests. The genetic composition and variability of populations might define the relative differences in the environmental response of C. calceolus. To address these aspects, a novel, recently developed universal method of DNA fingerprinting was applied for the first time for the Cypripedium genus. 22 specific PCR primers were tested to select those which reveal the highest level of genetic polymorphism. The three selected primers (yielding 40 loci) were applied to estimate the genetic variability among the plants within a site and between different sites. A rather high genetic diversity withi...
For the study, 16 lily genotypes were chosen, including fi ve Latvian varieties well adapted to t... more For the study, 16 lily genotypes were chosen, including fi ve Latvian varieties well adapted to the Latvian climate. The genotypes belong to three different sections and two intersection hybrids. Ovaries were cut in the 5 th , 10 th , 14 th , 20 th and 23 rd days after pollination and cultured on Murashige and Skoog basal medium
We have carried out restoring of some Latvian alfalfa genetic resources from seeds of accessions ... more We have carried out restoring of some Latvian alfalfa genetic resources from seeds of accessions that did not germinate in soil at all. Two of them were repatriated from the N. Vavilov All-Russian Institute of Plant Industry (multiplied more than 40 years ago) and three from the Research Institute of Agriculture (Latvia) (multiplied 15-20 years ago). For germination of old
The glycoalkaloid content in potato tubers can be influenced by several factors: variety, weather... more The glycoalkaloid content in potato tubers can be influenced by several factors: variety, weather, storage environment, maturity, damage, temperature and exposure to light. Potato varieties vary with regard to their inherited total glycoalkaloid (TGA) content. The problem in the practical use of most TGA detection methods is that they are money and time consuming. The aims of the investigation were adaptation of a rapid and rather cheap method and evaluation of TGA content of varieties included in Latvia potato genetic resources. The used method was based on three earlier elaborated protocols of different authors. 31 varieties of Latvian potato genetic resources were examined for TGA content for two years, 10 of them for three years. TGA content depending on the variety ranged from 2 till 27 mg 100 g -1 fresh weight, the variance between genotypes was high. The significant genotype influence on TGA content was established. The influence of growing conditions on TGA content was not s...
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
Molecular markers based on retrotransposons possibility of integration into genomes of many organ... more Molecular markers based on retrotransposons possibility of integration into genomes of many organisms are commonly used for genetic analysis of different species. The aim of this study was to test the possibility of use those markers in perch and detect the genetic diversity of populations of two lakes of the Latgale region of Latvia: Cirišs and Sventes. The distance between the lakes is nearly 60 km, they belong to the same Daugava River basin but are different from the ecological point of view. Forty-two blood samples of Perca fluviatilis were collected altogether. Extracted DNA was analyzed using inter-PBS amplification technique with specifically selected retrotransposonbased primers and agarose gel electrophoresis. Data of genetic diversity of lakes were calculated by POPGENE and NTSYS software. In total, 127 loci were found in two populations, 81 of them were polymorphic. In spite of the rather small distance between lakes Cirišs and Sventes, several differences in genetic variation of populations of two lakes were found. For example, the number of polymorphic loci in samples from Lake Sventes was 61, but only 47 from Lake Cirišs. A unique allele was found in Lake Sventes. Genetic similarity and distance between populations of lakes Cirišs and Sventes was 0.9288 and 0.0739, respectively. The results proved that molecular markers based on retrotransposons PBS regions can be very useful to test the genetic diversity of fish populations.
Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015
Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences, 2013
Audu kultûras apstâkïos panâkta tâdu vecu âboliòa un lucernas sçklu izdîgðana, kuriem bija zaudçt... more Audu kultûras apstâkïos panâkta tâdu vecu âboliòa un lucernas sçklu izdîgðana, kuriem bija zaudçta dîgtspçja parastos apstâkïos. Iegûti fertîli augi, kuri papildina pieejamos ìençtiskos resursus attiecîgo kultûraugu selekcijas vajadzîbai.
Urban Forestry & Urban Greening, 2015
ABSTRACT White clover (Trifolium repens L.) is a commonly cultivated legume with good ground cove... more ABSTRACT White clover (Trifolium repens L.) is a commonly cultivated legume with good ground cover potential often used with companion grass species in urban grassed areas. The effect of increased soil salinity on plant growth is an urgent problem in cities where NaCl is used as a de-icing material. The aim of this research was to examine the effect of different salinity levels and K supply induced responses and tolerance in the T. repens L variety ‘Daile’, a variety which is used in urban greenery. To analyze the impact of increased soil salinity and the antagonistic effect of K, the effect of gradually increasing NaCl (0; 20; 40; 60; 80; 100 mM) and K (+0; +100; +200; +300 mg/L) levels on T. repens plants was investigated in a pot experiment. Concentrations of 12 nutrients, Na and Cl were determined in the plant shoots and roots, as well as plant weight, Pv/Fm, P index (photosynthetic performance) and proline content. The results revealed that increased substrate salinity led to accumulation of both Na and Cl in tissues of T. repens and significantly reduced Mg. Na and Cl concentration in the plant shoots increased in accumulative manner, but in the roots, the concentration of both elements increased in the treatments with applied NaCl concentrations up to 60 mM. In the roots, a significant decrease of N, K, Mg, S, Mo and an increase of Na, Cl, Ca, Fe, Mn, Cu, Zn content was detected with increasing substrate salinity. Elevated soil salinity had a minor impact on the photosynthetic performance of T. repens. A significant decline in the fresh and dry biomass of the plant shoots was measured in all salinity treatments. In conditions of increasing soil salinity and K content, T. repens possessed several mechanisms of adaptive value, as well as changes in mineral nutrition. According to the obtained results, cultivation of T. repens variety ‘Daile’ in urban areas with slight or moderate salinity is possible.