Comprehensive Study of Si-Based Compounds in Selected Plants (Pisum sativum L., Medicago sativa L., Triticum aestivum L.).

This review describes the role of silicon (Si) in plants. Methods of silicon determination and speciation are also reported. The mechanisms of Si uptake by plants, silicon fractions in the soil, and the participation of flora and fauna in the Si cycle in terrestrial ecosystems have been overviewed. Plants of Fabaceae (especially Pisum sativum L. and Medicago sativa L.) and Poaceae (particularly Triticum aestivum L.) families with different Si accumulation capabilities were taken into consideration to describe the role of Si in the alleviation of the negative effects of biotic and abiotic stresses. The article focuses on sample preparation, which includes extraction methods and analytical techniques. The methods of isolation and the characterization of the Si-based biologically active compounds from plants have been overviewed. The antimicrobial properties and cytotoxic effects of known bioactive compounds obtained from pea, alfalfa, and wheat were also described.

Pressurized liquid extraction of cyclitols and sugars: optimization of extraction parameters and selective separation.

Cyclitols and sugars were obtained as a mixture from Medicago sativa L., in a comparative study by using maceration, and pressurized liquid extraction, as a modern and green extraction techniques. The influence of extraction parameters including: extraction temperature, time and number of cycles on the content of sugars and cyclitols was investigated based on response surface methodology. The highest total amount of sugars and cyclitols (62.27 ± 2.30 and 50.35 ± 0.77 mg/g of dry material, respectively) was obtained when extraction was performed at 88°C, for 22 min, in two cycles. The methodology used involved extraction, purification, selective separation (using yeast and anion exchange resin) and derivatization, followed by gas chromatography -mass spectrometry analysis. The use of yeast treatment realized an effective fractionation of cyclitols and sugars, which allowed the removal of most sugars. The involvement of anion exchange resin after yeast allowed the removal of sugar alcohols and lactose, together with other sugar traces remained and to obtain a solution containing six cyclitols. The recrystallization of dry residue after solvent evaporation, from ethanol, allowed us to obtain 14.65 mg of white pure crystals identified with NMR spectroscopy, liquid chromatography with mass spectrometry, gas chromatography with mass spectrometry, optical rotation and melting point as analysis D-pinitol.

Supercritical fluid extraction in isolation of cyclitols and sugars from chamomile flowers.

The aim of the present study was to develop an optimization procedure for supercritical fluid extraction parameters, in order to obtain the highest possible yield of sugars and cyclitols from plant material. Response surface methodology based on Box-Behnken design was applied to evaluate the effect of: temperature (40, 60, 80°C), pressure (100, 200, 300 bar), and co-solvent (methanol) percentage (20, 25, 30%). As a result of the optimization process, we found that the highest amount of sugars (15.02 mg/gof dried material) and cyclitols (0.86 mg/g of dried material) was obtained when the following parameters were applied: 80°C, 228 bar, and 30% of methanol. Moreover, co-solvent concentration and temperature had a higher influence onto the obtained amounts compared with the pressure.

Inositols' Importance in the Improvement of the Endocrine-Metabolic Profile in PCOS.

Polycystic ovary syndrome (PCOS) is one of the most common causes of infertility and metabolic problems among women of reproductive age. The mechanism of PCOS is associated with concurrent alterations at the hormonal level. The diagnosis assumes the occurrence of three interrelated symptoms of varying severity, namely ovulation disorders, androgen excess, or polycystic ovarian morphology (PCOM), which all require a proper therapeutic approach. The main symptom seems to be an increased androgen concentration, which in turn may contribute to different metabolic disorders. A number of papers have demonstrated the significant role of inositol therapy in PCOS. However, there is a lack of detailed discussion about the importance of myo-inositol (MI) and d-chiro-inositol (DCI) in reference to particular symptoms. Thus, the aim of this review is to present the effectiveness of MI and DCI treatment for PCOS symptoms. Moreover, the review is focused on analyzing the use of inositols, taking into account their physiological properties, together with the mechanism of individual PCOS symptom formation.

Mechanisms of hormonal regulation of endosperm cap-specific gene expression in tomato seeds.

The micropylar region of endosperm in a seed, which is adjacent to the radicle tip, is called the 'endosperm cap', and is specifically activated before radicle emergence. This activation of the endosperm cap is a widespread phenomenon among species and is a prerequisite for the completion of germination. To understand the mechanisms of endosperm cap-specific gene expression in tomato seeds, GeneChip analysis was performed. The major groups of endosperm cap-enriched genes were pathogenesis-, cell wall-, and hormone-associated genes. The promoter regions of endosperm cap-enriched genes contained DNA motifs recognized by ethylene response factors (ERFs). The tomato ERF1 (TERF1) and its experimentally verified targets were enriched in the endosperm cap, suggesting an involvement of the ethylene response cascade in this process. The known endosperm cap enzyme endo-ß-mannanase is induced by gibberellin (GA), which is thought to be the major hormone inducing endosperm cap-specific genes. The mechanism of endo-ß-mannanase induction by GA was also investigated using isolated, embryoless seeds. Results suggested that GA might act indirectly on the endosperm cap. We propose that endosperm cap activation is caused by the ethylene response of this tissue, as a consequence of mechanosensing of the increase in embryonic growth potential by GA action.

Changes in the Carbohydrate Profile in Common Buckwheat (Fagopyrum esculentum Moench) Seedlings Induced by Cold Stress and Dehydration.

Plant species are sensitive to stresses, especially at the seedling stage, and they respond to these conditions by making metabolic changes to counteract the negative effects of this. The objectives of this study were to determine carbohydrate profile in particular organs (roots, hypocotyl, and cotyledons) of common buckwheat seedlings and to verify whether carbohydrate accumulation is similar or not in the organs in response to cold stress and dehydration. Roots, hypocotyl, and cotyledons of common buckwheat seedlings have various saccharide compositions. The highest concentrations of cyclitols, raffinose, and stachyose were found in the hypocotyl, indicating that they may be transported from cotyledons, although this needs further studies. Accumulation of raffinose and stachyose is a strong indicator of the response of all buckwheat organs to introduced cold stress. Besides, cold conditions reduced d-chiro-inositol content, but did not affect d-pinitol level. Enhanced accumulation of raffinose and stachyose were also a distinct response of all organs against dehydration at ambient temperature. The process causes also a large decrease in the content of d-pinitol in buckwheat hypocotyl, which may indicate its transformation to d-chiro-inositol whose content increased at that time. In general, the sucrose and its galactosides in hypocotyl tissues were subject to the highest changes to the applied cold and dehydration conditions compared to the cotyledons and roots. This may indicate tissue differences in the functioning of the protective system(s) against such threats.

Identification and quantification of cyclitols and sugars isolated from different morphological parts of Raphanus sativus L.

Through this study, we aimed to develop a new analytical method for identification and quantification of sugars and cyclitols isolated from different morphological parts of Raphanus sativus L (R. sativus). Accelerated solvent extraction with water was involved for targets extraction. Solid phase extraction was used for purification and preconcentration, while high performance liquid chromatography with evaporative light scattering detector (HPLC-ELSD) was used for chromatographic analyses. A short method of only 30 min for a single analysis was developed finally. The obtained results, allowed for quantification of eight targets, i.e., three cyclitols (D-pinitol, allo-inositol and scyllo-inositol) and five sugars (xylose, D-mannose, D-fructose, D-glucose and sucrose) that were determined simultaneously using a single analysis. The developed method can be applied in industry as a routine method for analysis of sugars and cyclitols from different sources.

Exogenously Applied Cyclitols and Biosynthesized Silver Nanoparticles Affect the Soluble Carbohydrate Profiles of Wheat (Triticum aestivum L.) Seedling.

Cyclitols, such as myo-inositol and its isomers and methyl derivatives (i.e., d-chiro-inositol and d-pinitol (3-O-methyl-chiro-inositol)), are classified as osmolytes and osmoprotectants and are significantly involved in plant responses to abiotic stresses, such as drought, salinity and cold. Moreover, d-pinitol demonstrates a synergistic effect with glutathione (GSH), increasing its antioxidant properties. However, the role of cyclitols in plant protection against stresses caused by metal nanoparticles is not yet known. Therefore, the present study examined the effects of myo-inositol, d-chiro-inositol and d-pinitol on wheat germination, seedling growth and changes in the profile of soluble carbohydrates in response to biologically synthesized silver nanoparticles ((Bio)Ag NPs). It was found that cyclitols were absorbed by germinating grains and transported within the growing seedlings but this process was disrupted by (Bio)Ag NPs. Cyclitols applied alone induced sucrose and 1-kestose accumulation in seedlings slightly, while (Bio)Ag NP doubled the concentrations of both sugars. This coincided with a decrease in monosaccharides; i.e., fructose and glucose. Cyclitols and (Bio)Ag NPs present in the endosperm resulted in reductions in monosaccharides, maltose and maltotriose, with no effect on sucrose and 1-kestose. Similar changes occurred in seedlings developing from primed grains. Cyclitols that accumulated in grain and seedlings during grain priming with d-pinitol and glutathione did not prevent the phytotoxic effects of (Bio)Ag NPs.

Evolutionary dynamics of the chloroplast genome sequences of six Colobanthus species.

The complete plastome sequences of six species were sequenced to better understand the evolutionary relationships and mutation patterns in the chloroplast genome of the genus Colobanthus. The length of the chloroplast genome sequences of C. acicularis, C. affinis, C. lycopodioides, C. nivicola, C. pulvinatus and C. subulatus ranged from 151,050 to 151,462 bp. The quadripartite circular structure of these genome sequences has the same overall organization and gene content with 73 protein-coding genes, 30 tRNA genes, four rRNA genes and five conserved chloroplast open reading frames. A total of 153 repeat sequences were revealed. Forward repeats were dominant, whereas complementary repeats were found only in C. pulvinatus. The mononucleotide SSRs composed of A/T units were most common, and hexanucleotide SSRs were detected least often. Eleven highly variable regions which could be utilized as potential markers for phylogeny reconstruction, species identification or phylogeography were identified within Colobanthus chloroplast genomes. Seventy-three protein-coding genes were used in phylogenetic analyses. Reconstructed phylogeny was consistent with the systematic position of the studied species, and the representatives of the same genus were grouped in one clade. All studied Colobanthus species formed a single group and C. lycopodioides was least similar to the remaining species.

Retrotransposon-based genetic variation of Poa annua populations from contrasting climate conditions.

BACKGROUND: Poa annua L. is an example of a plant characterized by abundant, worldwide distribution from polar to equatorial regions. Due to its high plasticity and extraordinary expansiveness, P. annua is considered an invasive species capable of occupying and surviving in a wide range of habitats including pioneer zones, areas intensively transformed by human activities, remote subarctic meadows and even the Antarctic Peninsula region. METHODS: In the present study, we evaluated the utility of inter-primer binding site (iPBS) markers for assessing the genetic variation of P. annua populations representing contrasting environments from the worldwide range of this species. The electrophoretic patterns of polymerase chain reaction products obtained for each individual were used to estimate the genetic diversity and differentiation between populations. RESULTS: iPBS genotyping revealed a pattern of genetic variation differentiating the six studied P. annua populations characterized by their different climatic conditions. According to the analysis of molecular variance, the greatest genetic variation was recorded among populations, whereas 41.75% was observed between individuals within populations. The results of principal coordinates analysis (PCoA) and model-based clustering analysis showed a clear subdivision of analyzed populations. According to PCoA, populations from Siberia and the Kola Peninsula were the most different from each other and showed the lowest genetic variability. The application of STRUCTURE software confirmed the unique character of the population from the Kola Peninsula. DISCUSSION: The lowest variability of the Siberia population suggested that it was subjected to genetic drift. However, although demographic expansion was indicated by negative values of Fu's FS statistic and analysis of mismatch distribution, it was not followed by significant traces of a bottleneck or a founder effect. For the Antarctic population, the observed level of genetic variation was surprisingly high, despite the observed significant traces of bottleneck/founder effect following demographic expansion, and was similar to that observed in populations from Poland and the Balkans. For the Antarctic population, the multiple introduction events from different sources are considered to be responsible for such an observation. Moreover, the results of STRUCTURE and PCoA showed that the P. annua from Antarctica has the highest genetic similarity to populations from Europe. CONCLUSIONS: The observed polymorphism should be considered as a consequence of the joint influence of external abiotic stress and the selection process. Environmental changes, due to their ability to induce transposon activation, lead to the acceleration of evolutionary processes through the production of genetic variability.

Health-Promoting Properties of Selected Cyclitols for Metabolic Syndrome and Diabetes.

Cyclitols play a particularly important role in cell functioning because they are involved in ion channel physiology, phosphate storage, signal transduction, cell wall formation, membrane biogenesis, osmoregulation and they have antioxidant activity. They are involved in the cell membranes as a phosphatidyl myo-inositol, an inositol triphosphate precursor, which acts as a transmitter that regulates the activity of several hormones, such as follicle-stimulating hormone, thyrotropin, and insulin. The aim of this paper is to characterize the selected cyclitols: myo-inositol, D-chiro-inositol, and D-pinitol in type-2 metabolic syndrome and diabetes treatment. Results and discussion: Cyclitols have certain clinical applications in the treatment of metabolic syndromes and are considered to be an option as a dietary supplement for the treatment or prevention of gestational diabetes mellitus and type-2 diabetes. Improved metabolic parameters observed after using cyclitols, like myo-inositol, in the treatment of polycystic ovary syndrome and type-2 diabetes suggest that they may have a protective effect on the cardiovascular system. Pinitol, together with myo-inositol,maybe responsible for improving lipid profiles by reducing serum triglyceride and total cholesterol. Pinitol is also well-researched and documented for insulin-like effects. Myo-inositol, D-chiro-inositol, and D-pinitol indicate a number of therapeutic and health-promoting properties.

Jasmonic acid and ethylene are involved in the accumulation of osmotin in germinating tomato seeds.

The expression of SlNP24 encoding osmotin was studied in germinating tomato seeds Solanum lycopersicum L. cv. Moneymaker. The results show that the accumulation of the transcripts of SlNP24 and its potential upstream regulator TERF1 encoding an ethylene response factor was induced by ethylene and methyl jasmonate in germinating tomato seeds. There was no effect of gibberellins on the expression of the genes studied. The expression of SlNP24 was localized in the micropylar region of the endosperm of tomato seeds. The promoter of tomato osmotin was active in the endosperm cells of transgenic Arabidopsis thaliana seeds, which contain reporter genes under control of SlNP24 promoter. The activity of SlNP24 promoter in A. thaliana reporter line seeds was visible when the expression of its ortholog gene in A. thaliana (AtOMS34) was observed. The mechanism of induction and a possible role of NP24 in germinating tomato seeds are discussed.

The Healing-Promoting Properties of Selected Cyclitols-A Review.

INTRODUCTION: Myo-inositol and its derivatives cyclitols play an important role in the processes of cell regulation, signal transduction, osmoregulation, and ion channel physiology, and are a component of the cell membrane. Free cyclitols present in food or released during the degradation of galactosyl cyclitols by bacteria (in digestive tract) show some physiological benefits. AIM: The aim of this paper is to present and analyze the documented data about curative and healing properties of cyclitols. RESULTS AND DISCUSSION: Cyclitols are well known compounds in the treatment of an accompanied diabetes insulin resistance, and also obesity and polycystic ovarian syndrome. d-chiro-Inositol deficiency exacerbates insulin resistance in the liver, muscles, and fat, while depletion of myo-inositol results in the development of diabetic complications. Cyclitols are successfully applied in treatment of polycystic ovarian syndrome, simultaneous are observed effective reducing of BMI, improving the hormonal profile, and increasing fertility. Moreover, cyclitols have anti-atherogenic, anti-oxidative, anti-inflammatory, and anti-cancer properties. CONCLUSION: The properties of cyclitols may be a good therapeutic option in the reduction of metabolically induced inflammation. Due to well drugs tolerance and low toxicity of these compounds, cyclitols are recommend for pregnant women and also for children. Another advantage is their widespread presence and easy availability, which encourages their use in medicine.

The complete chloroplast genome of Colobanthus apetalus (Labill.) Druce: genome organization and comparison with related species.

Colobanthus apetalus is a member of the genus Colobanthus, one of the 86 genera of the large family Caryophyllaceae which groups annual and perennial herbs (rarely shrubs) that are widely distributed around the globe, mainly in the Holarctic. The genus Colobanthus consists of 25 species, including Colobanthus quitensis, an extremophile plant native to the maritime Antarctic. Complete chloroplast (cp) genomes are useful for phylogenetic studies and species identification. In this study, next-generation sequencing (NGS) was used to identify the cp genome of C. apetalus. The complete cp genome of C. apetalus has the length of 151,228 bp, 36.65% GC content, and a quadripartite structure with a large single copy (LSC) of 83,380 bp and a small single copy (SSC) of 17,206 bp separated by inverted repeats (IRs) of 25,321 bp. The cp genome contains 131 genes, including 112 unique genes and 19 genes which are duplicated in the IRs. The group of 112 unique genes features 73 protein-coding genes, 30 tRNA genes, four rRNA genes and five conserved chloroplast open reading frames (ORFs). A total of 12 forward repeats, 10 palindromic repeats, five reverse repeats and three complementary repeats were detected. In addition, a simple sequence repeat (SSR) analysis revealed 41 (mono-, di-, tri-, tetra-, penta- and hexanucleotide) SSRs, most of which were AT-rich. A detailed comparison of C. apetalus and C. quitensis cp genomes revealed identical gene content and order. A phylogenetic tree was built based on the sequences of 76 protein-coding genes that are shared by the eleven sequenced representatives of Caryophyllaceae and C. apetalus, and it revealed that C. apetalus and C. quitensis form a clade that is closely related to Silene species and Agrostemma githago. Moreover, the genus Silene appeared as a polymorphic taxon. The results of this study expand our knowledge about the evolution and molecular biology of Caryophyllaceae.

The impact of Cu treatment on phenolic and polyamine levels in plant material regenerated from embryos obtained in anther culture of carrot.

The influence of copper sulphate on the regeneration of carrot (Daucus carota L.) androgenic embryos and changes in the levels of phenolic substances and polyamines that might be indicative of the response to oxidative stress were investigated. The cultivation on the regeneration medium supplemented with Cu(2+) at the concentrations 1 and 10 microM for 15 weeks resulted in significant dose-dependent inhibition of the growth and organogenic ability of carrot embryos. The total content of phenolic acids (represented by the sum of all soluble and insoluble fractions) in the Cu(2+)-treated carrot cultures did not change in comparison with the control (0.1 microM Cu(2+)). However, the levels of phenolic acids in the individual fractions showed significant differences. The cultivation in the presence of increased Cu(2+) evoked first of all the rise of free chlorogenic and caffeic acids, and the increase in soluble ester-bound ferulic acid. Marked dose-dependent decline in the amount of ferulic acid incorporated into the cell walls of the Cu(2+)-treated carrot cultures was partly compensated by the increase in the content of p-hydroxybenzoic acid. Decline in the total polyamine contents in the carrot tissues cultivated in the presence of increased Cu(2+) concentrations was observed. The most abundant polyamine, both in a free and PCA-soluble conjugated forms, was putrescine, the least abundant was spermine, which occurred in free form only. While the levels of free polyamines slightly decreased in a dose-dependent manner in the Cu(2+)-treated cultures, those of PCA-soluble conjugates markedly rose (enhancement to 135 and 170% in 1 and 10 microM Cu(2+), respectively, compared with the control). The decline in the total polyamine contents was caused mainly by the decline in the levels of PCA-insoluble conjugates. The decrease observed in this fraction was approximately to 70 and 50% in 1 and 10 microM Cu(2+)-treated cultures, respectively, when compared with the control. The role of phenolic acids and polyamines in preventing Cu(2+)stress in the carrot tissues is discussed.

[Participation of annexin At1 in plant response to abiotic stress]. / Czy aneksyna AnnAtl z Arabidopsis thaliana uczestniczy w odpowiedzi organizmu na stres wywolany czynnikami abiotycznymi?

Annexins are calcium-dependent phospholipid-binding proteins existing both in animal and plant cells. Mammalian and especially human annexins were examined for many years, and their functions in these organisms are already well known, but it is not the case for plant annexins. On the basis of existing literature and experimental evidence, it can be proposed that plant annexins may have a role in stress response. Annexin At1 of Arabidopsis thaliana (AnnAt1) is one of eight proteins of this family in A. thaliana. In its sequence many potentially functional domains are found, owing to that this protein can play an important role in stress response of the organism. Considering literature data and our own experiments one can postulate that AnnAt1 has weak peroxidase activity and form oligomers in hydrogen peroxide-dependent manner. This can be important in response to oxidative stress. Also we found that this protein forms ion channel in pH-dependent manner. This phenomenon may have particular significance in maintaining calcium homeostasis in the cell and calcium signaling, therefore AnnAt1 may play different roles in regulating stress response of plant. This is extremely important because plants during growth and development have to cope different stress factors like drought, deficiency or excess of mineral compounds in the soil, as well as low or high temperatures.

The influence of several factors on the efficiency of androgenesis in carrot.

The influence of cultivar, donor plant and culture procedure on the efficiency of androgenesis was studied in carrot anther culture. Experiments were carried out on five carrot cultivars: CxC 9900 F1, Lucky B F1, HCM, Beta III and Perfekcja, which were chosen because of their high carotene contents. Two procedures of anther culture were compared: (1) incubation in darkness for two weeks, followed by exposure to continuous light and transfer onto a fresh medium of the same composition; and (2) incubation in darkness until embryos appeared, without transfer onto a fresh medium. Temperature was +27 degrees C all the time. Genotype played an important role in the process of androgenesis in carrot anther culture. The efficiency was the highest in cv. HCM - 5.6 embryos per 100 anthers. Considerable differences in the capacity for androgenesis were observed between individual donor plants. The ratio of embryos obtained per 100 anthers for cv. HCM varied from 0.0 to 48.9. The second procedure of anther culture proved to be more efficient, cheaper and less complicated.

The acquisition of desiccation tolerance in developing Vicia hirsuta seeds coincides with an increase in galactinol synthase expression and soluble α-D-galactosides accumulation.

Galactinol is the galactosyl donor for the biosynthesis of both the raffinose family oligosaccharides (RFOs) and galactosyl cyclitols (Gal-C). Its synthesis by galactinol synthase (GolS, EC 2.4.1.123) is the first committed step of the soluble α-D-galactosides biosynthetic pathway in orthodox seeds. The deposition of galactosides in seeds is suggested to be associated with desiccation tolerance (DT). In this work, for the first time, we cloned and characterized two Vicia hirsuta (L.) S.F. Gray galactinol synthase genes (VhGolS1, VhGolS2), analyzed galactinol synthase activity and measured the accumulation of galactosides of both sucrose and D-pinitol in relation to the acquisition of DT in developing seeds of this wild species. A developmentally induced increase of VhGolS1 expression preceded the rise of GolS activity in crude protein extract from maturing seeds, while the expression of the VhGolS2 gene remained low. GolS activity peaked just after the beginning of the maturation drying phase. The increase of GolS activity was not followed by galactinol accumulation, instead the high enzyme activity was related to high levels of galactose bound in soluble galactosides of the RFO and galactosyl pinitol series. Acquisition of DT coincided with an increase of VhGolS1 expression, high galactinol synthase activity and the accumulation of oligogalactosides in seeds. DT was positively correlated with the high content of soluble α-D-galactosides of both the RFO and galactosyl pinitol series as well as with the amount of galactose bound in these galactosides.

Morphological diversity of androgenic carrot plants.

The aim of this study was to evaluate phenotypic variation of R0 androgenic plants obtained from four seed sources and donor plants by anther culture. Several morphological traits (leaf size, petiole length, leaf division, cortex colour) and the range of diversity were evaluated. There was large variation in all traits among the donor varieties. Especially leaf division and cortex colour differed significantly among the androgenic plants that came from different seed sources. The plants regenerated from four donor plants of variety 62 were significantly different in most traits except for leaf width and cortex colour. Evaluation of R1 plants will demonstrate whether the R0 variation observed is due to genetic variation or physiological differences from tissue culture.

Anatomical features and ultrastructure of Deschampsia antarctica (Poaceae) leaves from different growing habitats.

BACKGROUND AND AIMS: The leaf anatomy and ultrastructure of Deschampsia antarctica (Poaceae) plants growing in three different habitats (a dry site in the Antarctic tundra, a wet site in a zone exposed to sea spray and a greenhouse) were investigated. The ultrastructure of the leaves of D. antarctica has not been studied before. METHODS: Semi-thin sections of the D. antarctica leaves were stained with toluidine blue and viewed using a light microscope. Ultra-thin sections stained with uranyl acetate and lead citrate were examined using a transmission electron microscope. KEY RESULTS: Plants growing in the Antarctic tundra and in a greenhouse had stronger xerophytic features than those growing at the seashore. The stress response of D. antarctica plants growing in the wet environment, exposed to high salinity and flooding, included: irregular mesophyll cells, large intercellular spaces in the parenchymatic layer, bulliform epidermal cells and vascular bundles surrounded with deformed outer and inner bundle sheaths of leaves. The highest number of sclerenchymatic fibres is characteristic of the leaves of plants growing in a greenhouse, whereas the smallest was of plants growing in a wet habitat. Stress conditions can disturb the formation of sclerenchymatic fibres. In plants growing in the Maritime Antarctic the chloroplasts of the mesophyll cells of leaves are of an irregular shape, with pockets or invaginations inside the organelles and outgrowths. Both of them make the surfaces of chloroplasts larger, and result in an increase in the amount of substances exchanged between the chloroplasts and cytoplasm or the other organelles. The leaf mesophyll cells of D. antarctica plants growing in Antarctica contain atypical structures including numerous vesicles of different sizes and concentrically arranged membranes. CONCLUSIONS: The anatomical and ultrastructural features of the leaf and their changes under stress conditions are considered in relation to the adaptations of D. antarctica to the climate conditions in the Maritime Antarctic.