Dace Grauda

Microspore embryogenesis and programmed cell death in barley: effects of copper on albinism in recalcitrant cultivars

Albinism remains a major problem in cereal improvement programs that rely on doubled haploid (DH) technology, and the factors controlling the phenomenon are not well understood. Here we report on the positive influence of copper on the production of DH plants obtained through microspore embryogenesis (ME) in recalcitrant cultivars of barley (Hordeum vulgare L.). The presence of copper sulphate in the anther pre-treatment medium improved green DH plant regeneration from cultivars known to produce exclusively albino plants using classical procedures. In plastids, the effect of copper was characterized by a decrease in starch and a parallel increase in internal membranes. The addition of copper sulphate in the ME pre-treatment medium should enable breeders to exploit the genetic diversity of recalcitrant cultivars through DH technology. We examined programmed cell death (PCD) during microspore development to determine whether PCD may interfere with the induction of ME and/or the occurrence of albinism. By examining the fate of nuclei in various anther cell layers, we demonstrated that the kinetics of PCD in anthers differed between the barley cultivars Igri and Cork that show a low and a high rate of albinism, respectively. However, no direct correlation between PCD in the anther cell layers and the rate of albinism was observed and copper had no influence on the PCD kinetic in these cultivars. It was concluded that albinism following ME was not due to PCD in anthers, but rather to another unknown phenomenon that appears to specifically affect plastids during microspore/pollen development.

Reaction of Flax (Linum Usitatissimum L.) Calli Culture to Supplement of Medium by Carbon Nanoparticles

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

Anther Culture Effectiveness in Producing Doubled Haploids of Cereals/ Putekðòu Kultûras Efektivitâte Graudaugu Dubultoto Haploîdu Izveidoðanâ

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. Abstract Darba mçríis bija uzlabot dubultoto haploîdu (DH) lîniju iegûðanas metodiku ar putekðnîcu kultûru palîdzîbu Latvijâ svarîgiem graudaugiem: mieþiem, vasaras un ziemas kvieðiem. Kâ izejas materiâls pçtîjumam kalpoja F1 un F2 paaudzes selekcionâru iegûtie hibrîdi. Pçtîjuma rezultâti parâdîja, ka vara sulfâta pievienoðana koncentrâcijâ 2,5 mg/l mieþu pirmapstrâdes barotnei un gan mieþu (C3), gan kvieðu (ðíidrâ AMC) kallusu indukcijas barotnçm paaugstina zaïo augu-reìenerantu iznâkumu. Liela skaita DH lîniju iegûðanu ar putekðnîcu kultûras palîdzîbu var organizçt divos etapos: pirmajâ nosaka hibrîdu atsaucîbu putekðnîcu kultûrâ un otrajâ masveidâ izmanto tikai atlasîtos hibrîdus ar augstu spçju veidot zaïus augus-reìenerantus

Recovering Genetic Resources of Some Legume Species of Latvian Origin by Plant Tissue Culture

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 Audu kultūras apstākļos panākta tādu vecu āboliņa un lucernas sēklu izdīgšana, kuriem bija zaudēta dīgtspēja parastos apstākļos. Iegūti fertīli augi, kuri papildina pieejamos ģenētiskos resursus attiecīgo kultūraugu selekcijas vajadzībai.

Amber Particles as Living Plant Cell Markers in Flow Cytometry / Dzintara Daļiņas Kā Dzīvu Augu Šūnu Marķieri Plūsmas Citometrijā

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. Labi zināma ir dzintara labvēlīgā ietekme uz dažādiem organismiem, tomēr ir ļoti maz pētījumu par dzintara ietekmi uz augu šūnām. Tādēļ šī pētījuma mērķis bija noskaidrot nano un mikro lieluma (5 nm-3 μm) dzintara daļiņu un dzintara komponentu (spirtā šķīstošā dzintara frakcija un sukcināta) ietekmi uz augu somatiskajām un gametiskajām šūnām, un noskaidrot dzintara daļiņu piemērotību dzīvu augu šūnu iezīmēšanai urbānās vides pētījumiem, izmantojot plūsmas citometriju. Relatīvā fluorescence, izmantojot BD FACSJazz® šūnu šķirotāju ar plūsmas citometra funkciju, tika noteikta èetru dažādu ģinšu sugu (Argyranthemum frutescens, Cyclamen persicum, Hordeum vulgare, Linum usitatissimum) augu šūnām pēc 2 un 24 stundu kultivācijas barotnēs ar un bez dzintara daļiņām vai dzintara komponentiem. Konstatēts, ka dzintara daļiņu klātbūtne visām pētīto augu šūnām ievērojami palielināja relatīvo fluorescenci. Dzintara komponentu ietekme uz šūnu relatīvās fluorescences izmaiņām nebija būtiska, salīdzinot ar dzintara daļiņu ietekmi. Dzintara daļiņas nesamazināja dzīvo šūnu daudzumu paraugos. Konstatēts, ka dzintara daļiņas (5 nm-3 μm) var izmantot kā marķierus dzīvo šūnu iezīmēšanai plūsmas citometrijas pētījumos.

Combined Effects of 50 Hz Electromagnetic Field and SiO2 Nanoparticles on Oxidative Stress in Plant’s Gametic Cells / Zemfrekvences (50 Hz) Elekromagnētiskā Lauka Un SiO2 Nanodaļiņu Kombinētā Ietekme Uz Augu Gametisko Šūnu Oksidatīvo Stresu

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 Urbānajā vidē dzīvie organismi atrodas nepārtrauktā saskarē ar dažāda veida piesārņojumu. Gan zemfrekvences elektromagnētiskais lauks (ZF EML), gan SiO2 nanodaļiņas ir vispārzināmi urbānās vides piesārņojuma veidi. Kombinēta zemferekvences elektromagnētiskā lauka un SiO2 ietekme uz šūnām ir maz pētīta. Šī pētījuma mērķis bija noteikt ZF EML un bioloģiski aktīvu (diametrā mazākas par 20 nm) SiO2 nanodaļiņu ietekmi uz augu gametiskajām šūnām. Kā modeļa objekts pētījumā tika izmantotas Cyclamen persicum gametiskās šūnas vienkodola attīstības stadijā. Gametiskās šūnas tika kultivētas MS barotnē. Pirms ievietošanas ZF EML šūnas 1 h tika inkubētas barotnē, kam pievienoja SiO2 nanodaļiņu suspensiju (1 mg/10 ml). Šūnas tika apstrādātas ZF EML 50 Hz ar blīvumu 50, 100, 200 un 400 μT. Šūnu relatīvās fluorescences izmaiņas tika noteiktas ar plūsmas citometru (BD FACSJazz®). Parādīts, ka gan SiO2 klātūtne kultivācijas barotnē gan šūnu ievietošana ZF EML statistiski ticami palielina gametisko šūnu fluorescenci. Šūnu apstrāde ar ZF EML, pēc to inkubācijas SiO2 nanodaļiņu suspensijā, statitiski ticami samazināja šūnu relatīvo fluorescenci. Rakstā tiek apspriesti iespējamie šāda efekta iemesli

Genetic Diversity of Mute Swan Population of the Riga Urban Area

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.