We present some results of a six-year (2008-2013) study in two localities of Liparis loeselii (L.) Rich. near Lake Engure. The annual cycle of L. loeselii, an early successional species, may indicate its potential survival in its typical wet habitat with fluctuating levels of water. Flowering of L. loeselii usually begins in the first decade of June and lasts for several weeks. If the initiation of development was delayed, leaves and inflorescence started to grow almost simultaneously. Development of the first fruit began during flowering and continued to August. Ripening of fruit and seeds occurred in September-October, and they were dispersed mostly by melt water of snow in spring, which is very important for populations in sites overgrowing with perennial herbs. The previous season capsules of L. loeselii remained till the middle of the next growing season; a part of the seeds remained in capsules and less than 1% of seeds had viable embryos. This may increase the survival potential of the population. The studies of herbarium records of L. loeselii in the area of Lake Engure showed that the annual cycles of L. loeselii have been similar and that the species has not responded drastically to climate change.

2 Стендский исследовательский центр Института сельскохозяйственных ресурсов и экономики, Латвийский сельскохозяйственный университет, Стенде, ЛатвияИзучено генетическое разнообразие растений-регенерантов пшеницы (Triticum aestivum L.), которые созданы методом культуры пыльников из гибридов, используемых в селекции этой культуры в Латвии. Метод проточной цитометрии применяли для определения плоидности каждого зеленого растения-регенеранта. В свою очередь, универсальным iPBS (inter primer binding sites) методом, основанном на анализе характерных последовательностей ретротранспозонов, определяли генетическое разнообразие этих растений. Анализу подвергали потомство 13 гибридов различного происхождения. В листьях большинства растений были миксоплоидные клетки. Семена дали только растения, имеющие клетки с плоидностью 2n = 6x. Большинство фертильных растений содержало в листьях более чем 40 % гексаплоидных (6x) клеток. Доля гексаплоидных клеток и их распределение по плоидности зависели от генотипа материнского гибридного растения. Доля спонтанной диплоидизации также зависела от генотипа растения. В описываемом эксперименте колхицинирование не оказало достоверного влияния на выход фертильных растений. У одного гибридного растения обнаружена новая доминантная аллель, отсутствующая у обоих родите лей, что указывает на возможное передвижение ретро транс позонов. Генетическое разнообразие растений-регенерантов, созданных методом культуры пыльников, вызвано как расщеплением родительских аллелей, так и сомаклональной изменчивостью.Ключевые слова: культура пыльников; ДГ-линии; селекция пшеницы; плоидность; проточная цитометрия; iPBS.The study of genetic diversity of wheat (Triticum aesti vum L.) plants-regenerants produced by anther culture method from hybrids involved in the Latvian wheat breeding programme was performed. Flow cytometry was used to test ploidy of 3 × 10 3 cells of each green plantregenerant, and universal retrotransposon based iPBS (inter primer binding sites) method were used to establish genetic diversity of plants-regenerants. Progenies of 13 genetically distant hybrids were involved in the study. Most of plants-regenerants have leaves with mixoploid cells. Seeds were formed only by plants-regenerants that had cells with (2n = 6x) ploidy. Majority of fertile plantsregenerants have more than 40 % of hexaploid (6x) cells. The percentage of 6x cells in plants-regenerants and diversity in cell ploidy demonstrated association with mother plant (hybrid) genotype. Percent of spontaneous diplodization was also genotype-dependent. In this experiment colchicine treatment had no significant influence on outcome of fertile plants-regenerants. New dominant allele in a hybrid plant was found in comparison with both parents what indicated possible retrotransposon moving. Genetic diversity of the plants-regenerants obtained in anther culture is a combination of parent's allele segregation and somaclonal variation.

Nanoparticles (nano-scale particles (NSPs)) are defined as particles with dimensions less than 100 nm. SiO₂ nanoparticles are one of the most widely common nanoparticles in the environment, particularly in urban areas. The sources of SiO₂nanoparticles are very different, including natural nanoparticles, anthropogenic and engineered nanoparticles. The SiO₂nanoparticles could be considered a source of different pollution effects on leaving organisms. Nevertheless, knowledge of the mechanisms, through which the SiO₂nanoparticles affect cells, is incomplete. The aim of the research was to elaborate a method to determine changes in relative fluorescence of both somatic and immature gametic plant cells in presence of SiO₂ nanoparticles. Relative cell fluorescence was measured with BD FACSJazz® cell sorter using 488 nm exciting laser light. Mean cell fluorescence was determined for samples of purified cell suspension. Gates of different size and shape were preliminary tested to find those with the lowest CV. Cell plots were created by BS FACS Software 1.0.0.650. The densest part of the plot was gated using oval-shaped gate. The gate included 95-99% of all cells. A logarithmic scale in arbitrary fluorescence units was applied to determine cell relative fluorescence. More than 10 000 cells were gated and analysed from each sample. Somatic cell culture from callus culture initiated from leaves of flax (<em>Linum usitatissimum) </em>was obtained. The relative fluorescence of the somatic cells had large distribution, since the cells differ by many parameters (size, shape, metabolism etc.). Immature pollen cells (one-nucleus stage) as best for SiO₂ nanoparticles influence investigation were found. The influence of SiO₂ nanoparticles on several plant species (<em>Cyclamen persicum, Tilia cordata, Hordeum vulgare</em> and <em>Triticum </em><em>aestivum</em>) immature pollen cells were investigated. A significant increase in relative cell fluorescence was observed for all mentioned plant species cells after incubation in SiO₂ nanoparticles suspension. It was found that cell relative fluorescence was dependent on cultivation duration in SiO₂ nanoparticles suspension.

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.

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