Antarctica Plants Research Articles

Salt tolerance traits in Deschampsia antarctica Desv.

AbstractDeschampsia antarctica Desv. (Poaceae) grows in coastal habitats in the Maritime Antarctic where it is often exposed to sea spray. Salt crystals have been observed on the surface of leaves in plants treated with high NaCl. We investigated if D. antarctica is a salt tolerant species that allows sodium ions to diffuse into the root where a salt overly sensitive (SOS) system extrudes Na+ from root cells and facilitates its movement through the xylem up to the leaves. Leaf epidermis, physiological parameters and sodium transporters in D. antarctica plants exposed to NaCl were studied over 21 days. Epidermal scanning electron microscopy showed trichome induction in the leaves of salt treated plants. In addition, salt treated plants showed increased sodium and proline levels with a concomitant increased expression of SOS genes (1 and 3). These results indicate that Na+ is taken up by the roots of D. antarctica and transported to the leaves. The sodium flux may be controlled by SOS1 activity. Up-regulation of the SOS1 gene may be involved in the increased sodium levels observed in the leaves of salt treated plants. Trichomes may also be involved in sodium exudation through the leaves under saline conditions.

Peculiarities of chromosomal variability in cultured tissues of Deschampsia antarctica Desv. plants with different chromosome numbers

Aim. To clarify the details of chromosome variation in calli derived from D. antarctica plants in the initial passages of the culture in vitro. Methods. Induction of callus from root explants of plants, which were grown from seeds, and consequent subcultivation of tissue culture. Cytogenetic analysis of squashed slides stained by acetic-orcein and counting the number of chromosomes in mitotic metaphase plates. Results. There were analyzed the cultured tissues derived from D. antarctica plants with different chromosome numbers: diploid plants (2n=26), mixoploid plant with B-chromosomes (2n=26+1-3B), and mixoploid plant with near-triploid modal class (2n=36, 38). Analysis of callus tissues of all plants at 2-4 passages revealed mixoploidy, presence of polyploid and aneuploid cells. The modal class in all studied calli was composed of diploid and aneuploid cells with near-diploid chromosome number. The cytogenetic structure of cell population of cultured tissues was found to vary with characteristics of the karyotype of donor plant. The largest range of variation in the number of chromosomes (from 18 to 63 chromosomes) was found in tissue culture of diploid plant (2n=26) from the Galindez Island, and the highest frequencies of polyploid (47 %) and aneuploid cells were in the culture of mixoploid plant with near-triploid modal class from the Big Yalour Island. Conclusions. In different D. antarctica cultured tissues at the early stages of the culture, the modal class was composed of diploid cells and cells with near-diploid chromosome number irrespective of karyotype of donor plant (diploid, mixoploid poliploid).Key words: Deschampsia antarctica Desv., plant tissue culture, chromosomal variability in vitro, mixoploidy.

Enhanced tolerance of Deschampsia antarctica Desv. to the mutagenic effect of cadmium ions

Aim. To study the potential effects of different concentrations of cadmium ions on antarctic plant D. antarctica using PCR analysis. Methods. Plants were grown in vitro on B5 Gamborg and Eveleigh agar medium supplemented with CdCl2. Genetic rearrangements were studied by PCR-analysis using ISSR- and IRAP-primers. Results. Genetically identical plants of D. antarctica obtained by microclonal propagation in vitro were used for the study of mutagenic effect of cadmium ions. The influence of Cd2+ was investigated within the concentration ranging from 0.1 to 10 mM. The results of cultivation of D. antarctica plants in the presence of cadmium ions for 63 days allow to determine the concentration range that does not inhibit the growth of the plants in vitro, and it was up to 1 mM. It was found that toxicant concentrations of 0.1 and 0.2 mM did not cause changes in the profiles of PCR products. After growing the plants with 0.2–1 mM CdCl2 for 17 days, the changes in the profiles of PCR products, indicating the mutagenic impact, were observed at concentrations of 0.6 mM or above; moreover, the number of changes increased in dependence on the concentration of heavy metal. Prolonged influence (140-265 days) of cadmium ions in relatively low concentrations (0.1 mM and 0.4 mM) did not cause detectable mutations. Conclusions. D. antarctica, a plant extremophile, which has evolved mechanisms of resistance to a variety of extreme conditions as a result of adaptation to the existence in the harsh conditions of Antarctica, shows enhanced resistance to cadmium ions in comparison with other species of vascular plants. Inhibition of growth occurs at Cd2+ concentrations of 0.1 mM or above, whereas concentrations of 1 mM or above cause cessation of growth and death of plants. Mutagenic effect on D. antarctica was observed at Cd2+ concentrations of above 0.4 mM. After prolonged growth of plants (for 3–8 months) at cadmium ions concentrations of 0.1–0.4 mM, genetic changes was not found.Keywords: Deschampsia antarctica Desv., plants in vitro obtained by microclonal propagation, cadmium ions, mutagenic effect, PCR-analysis.

Successional patterns along soil development gradients formed by glacier retreat in the Maritime Antarctic, King George Island

Maritime Antarctica is severely affected by climate change and accelerating glacier retreat forming temporal gradients of soil development. Successional patterns of soil development and plant succession in the region are largely unknown, as are the feedback mechanisms between both processes. Here we identify three temporal gradients representing horizontal and vertical glacier retreat, as well as formation of raised beaches due to isostatic uplift, and describe soil formation and plant succession along them. Our hypotheses are (i) plants in Antarctica are able to modulate the two base parameters in soil development, organic C content and pH, along the temporal gradients, leading to an increase in organic carbon and soil acidity at relatively short time scales, (ii) the soil development induces succession along these gradients, and (iii) with increasing soil development, bryophytes and Deschampsia antarctica develop mycorrhiza in maritime Antarctica in order to foster interaction with soil. All temporal gradients showed soil development leading to differentiation of soil horizons, carbon accumulation and increasing pH with age. Photoautptroph succession occurred rapidly after glacier retreat, but occurrences of mosses and lichens interacting with soils by rhizoids or rhizines were only observed in the later stages. The community of ground dwelling mosses and lichens is the climax community of soil succession, as the Antarctic hairgrass D. antarctica was restricted to ornithic soils. Neither D. antarctica nor mosses at the best developed soils showed any sign of mycorrhization. Temporal gradients formed by glacier retreat can be identified in maritime Antarctic, where soil development and plant succession of a remarkable pace can be observed, although pseudo-succession occurs by fertilization gradients caused by bird feces. Thus, the majority of ice-free surface in Antarctica is colonized by plant communities which interact with soil by litter input rather than by direct transfer of photoassimilates to soil.

Pollen record of disturbed topsoil as an indirect measurement of the potential risk of the introduction of non-native plants in maritime Antarctica

This is a study of current pollen rain on soil disturbed by human use on the Fildes Peninsula, King George Island, South Shetland Islands. A sector strongly affected by human activity, an area between the Eduardo Frei Montalva Chilean Air Force (FACH) base and the Professor Julio Escudero base of the Chilean Antarctic Institute (INACH) were sampled. A less used sector associated with scientific activity and controlled tourism, Ardley Island, and an area of low human activity, the terminal moraine of the Collins glacier, were also sampled. The samples were collected in the southern summer of 2015 and kept in the Palynology and Plant Ecology Laboratory of the Los Angeles Campus of the Universidad de Concepcion, Chile. The area of greatest human activity concentrated the greatest diversity (12 taxa) of pollen grains. Three taxa are considered native to the region. Non-native taxa determined for this sector in turn had the greatest invasion (INV) factor. The dominant families were Brassicaceae and Asteraceae. The results for Ardley and Collins represent the cryptogamic flora and grasses typical of the ecosystem. Under the current climate change scenario, the pollen rain in Antarctic soil, in addition to obeying the random patterns of its natural dispersion, could be interpreted as an indirect measurement of the potential risk of the passive transport of propagules to Antarctica mediated by human beings.

Assessing the importance of human activities for the establishment of the invasivePoa annuain Antarctica

Because of its harsh environmental conditions and remoteness, Antarctica is often considered to be at low risk of plant invasion. However, an increasing number of reports have shown the presence and spread of non-native plants in Antarctica; it is therefore important to study which factors control the invasion process in this ecosystem. Here, we assessed the role of different human activities on the presence and abundance of the invasive Poa annua. In addition, we performed a reciprocal transplant experiment in the field, and a manipulative experiment of germination with P. annua and the natives Colobanthus quitensis and Deschampsia antarctica, in order to unravel the effects of physical soil disturbance on the establishment and survival of P. annua. We found a positive correlation between abundance of P. annua and level of soil disturbance, and that survival of P. annua was 33% higher in sites with disturbed soil than non-disturbed. Finally, we found that disturbance conditions increased germination for P. annua, whereas for native species germination in experimentally disturbed soil was either unchanged or reduced compared to undisturbed soil. Our results indicate that human activities that modify abiotic soil characteristics could play an important role in the abundance of this invasive species. If the current patterns of human activities are maintained in Antarctica, the establishment success and spread of P. annua could increase, negatively affecting native flora.Keywords: Alien species; Colobanthus quitensis; Deschampsia antarctica; human disturbance; Poa annua; tourists.(Published: 23 June 2014)Citation: Polar Research 2014, 33, 21425, http://dx.doi.org/10.3402/polar.v33.21425

New forms of chromosome polymorphism in Deschampsia Antarctica Desv. from the Argentine Islands of the Maritime Antarctic region

Cytogenetic analysis of D. antarctica plants from the Argentine Islands of the Maritime Antarctic region was performed. Chromosome number 2n = 26 was determined for most of the samples. New forms of chromosome polymorphism for the species were demonstrated for the first time. In particular, the plants from Darboux Island were found, to have some cells that contained one supernumerary B-chromosome along with 26 chromosomes of a regular set. The plants from Great Yalour Island were determined to be mixoploid – the number of chromosomes ranged from 13 to 39. The occurrence of new and unknown earlier karyotypic forms of D. antarctica might have resulted from increased genome instability due to the extreme environmental conditions in the Argentine Islands region.

Do Antarctic lichens modify microclimate and facilitate vascular plants in the maritime Antarctic? A comment to Molina‐Montenegro et al. ()

AbstractA recent article published by Molina‐Montenegro et al. (Journal of Vegetation Science24: 463) examines the association of Antarctic native plant and lichen species to the lichen Usnea antarctica on Fildes Peninsula, King George Island, maritime Antarctica. The authors report that on two sites, five out of 13 and four out of 11 species of lichens and mosses were spatially associated with U. antarctica, suggesting positive interactions between them. Although Deschampsia antarctica does not grow naturally associated with U. antarctica, Molina‐Montenegro et al. carried out a transplantation experiment to demonstrate that the macrolichen acts as a nurse plant, improving the survival of the grass. Serious conceptual and methodological discrepancies emerge from a critical evaluation of this study, challenging their conclusions. First, we suspect that the author confused some lichen taxa, and we also disagree with macrolichens being treated as cushion plants, because rootless, poikilohydric and poikilothermic thallophytes such as lichens are unable to create a stable, enclave‐like microhabitat as vascular cushion plants do. Indeed, a critical evaluation of some of the micro‐environmental parameters measured indicates that there are no biologically meaningful differences between the U. antarctica thalli and surrounding open areas. Second, the lack of consideration of the life history of the species under study leads to confusion when (a) referring to the succession sequence of species that colonize the studied area and (b) interpreting the putative distribution patterns promoted by Usnea versus the substrate preferences of associated species. Third, the authors intend to demonstrate experimentally that Usnea can facilitate the survival of D. antarctica plants, transplanting adult plants and not seedlings between the lichen thalli, and it is not clear how the grass was planted – between or within the lichens – as at both experimental sites the lichens grow on stones or rocks. Facilitative interactions are present in the Antarctic and may play a pivotal role in the structure and functioning of the fragile Antarctic ecosystems. However, more rigorous and well‐planned research is needed to assess its presence, importance and involved mechanisms.

Phage detection in the rhizosphere of higher antarctic plants using transmission electron microscopy

This work is focused on electron microscopy of soil samples from root zone of higher Antarctica plants Deschampsia antarctica and Colobanthus quitensis for detection of bacteriophages. Here we compared several techniques and proposed optimal method for isolation of phage suspensions from the substrate. For the first time, the biodiversity of bacteriophages and virus-like particles (VLPs) in the root zone of Antarctic plants has been evaluated. According to morphological description, the dimensions and taxonomic position of several bacteriophages were elucidated. Possible reasons for degradation of virus particles observed during the microscopy studies have been suggested.

Fuegian plants in Antarctica: natural or anthropogenically assisted immigrants?

Two species of flowering plant of Fuegian montane provenance have been discovered on Deception Island in the maritime Antarctic, 950 km south of South America. Four individuals of Nassauvia magellanica and one of Gamochaeta nivalis (both Asteraceae) are growing robustly and in close proximity of each other on dry ash and scoria soil near a ruined whaling station which, in recent years, has been frequently visited by large numbers of ship-borne tourists. The Protocol on Environmental Protection to the Antarctic Treaty and the Management Plan for the island, designated an Antarctic Specially Managed Area, provide strict regulations for the conduct of visitors to this site and precautions against the accidental introduction of non-indigenous species. While their establishment on this remote volcanic island may have been anthropogenically mediated, natural immigration cannot be ruled out as both species produce seed adapted for wind-dispersal in their native Tierra del Fuego. The ecological consequences if one or both of these aliens spreads beyond their present restricted location are considered. While determined efforts are being made to implement rigorous biosecurity measures in Antarctica, current Antarctic Treaty policy on dealing with colonizing invasive alien species is indecisive and requires urgent action and clear recommendations.

Effects of neighboring plants on the growth and reproduction of Deschampsia antarctica in Antarctic tundra

Populations of the two native vascular plant species on the Antarctic Peninsula have increased over the past 40 years. This increase has been attributed to improved reproductive performance resulting from regional warming and increased growing season length. However, little is known of the influence that vascular plants have on the performance of neighboring plants in developing and well-established communities. We compared the aboveground growth and reproduction of Deschampsia antarctica plants growing alone or in close proximity to neighboring plants (D. antarctica, Colobanthus quitensis, or mosses) at a young, recently colonized and an older, well-developed plant community on the Antarctic Peninsula to assess whether neighboring plants had a positive or negative effect on D. antarctica performance, and whether these effects varied from young to old communities. In both communities, tillers on D. antarctica plants near neighbors produced 48–89% fewer leaves and 49–93% fewer tillers than those on D. antarctica plants growing alone. These tillers also had relative growth rates that were 25–66% lower- and tiller-size indices that were 42–87% less than those on plants growing alone. In addition, the biomass of tillers on plants growing near neighbors was 40–91% lower than those on plants growing alone. Leaf and tiller production was generally higher in the older, more developed community than in the younger community. Our findings illustrate that vegetative growth of D. antarctica is reduced when growing in close proximity to neighboring plants, suggesting that negative plant interactions are an important constraint at our field sites.

Реакція відповіді рослин на УФ-В опромінення та оксидний стрес

The effect of stress factors – ultraviolet radiation (UV-B) and hydrogen peroxide (H2O2) upon two species of Deschampsia plants – D. antarctica and D. caespitosa were studied. Investigations performed with D. antarctica plant samples delivered of Antarctic and D. caespitosa from Carpathian Mountains showed that UV-B radiation caused changes mainly pigment composition - chlorophyll a and almost all (except violaxanthin) carotenoids. Lipid composition was characterized by accumulation of triacylglicerols, sulphoquinovosyl diacylglycerol and phopsphatydylcholine while monogalacto-syldiacylglycerol quantity decreased. H2O2 treatment cause increase chlorophyll a content in both species and carotenoids in D. antarctica plants. Concerning glycolipid composition one could see monogalactosyldiacylglycerol content decrease in D. caespitosa whereas only insignificant SQDG enlargement was noted in D. antarctica leaves.

Origins of native vascular plants of antarctica: Comments from a historical phytogeography viewpoint

The article provides an overview of the problem of origin of the only native vascular plants of Antarctica, Deschampsia antartica (Poaceae) and Colobanthus quitensis (Caryophyllaceae), from the viewpoint of modern historical phytogeography and related fields of science. Some authors suggested the Tertiary relict status of these plants in Antarctica, while others favour their recent Holocene immigration. Direct data (fossil or molecular genetic ones) for solving this controversy is still lacking. However, there is no convincing evidence supporting the Tertiary relict status of these plants in Antarctica. Most probably D. antarctica and C. quitensis migrated to Antarctica in the Holocene or Late Pleistocene (last interglacial?) through bird-aided long-distance dispersal. It should be critically tested by (1) appropriate methods of molecular phylogeography, (2) molecular clock methods, if feasible, (3) direct paleobotanical studies, (4) paleoclimatic reconstructions, and (5) comparison with cases of taxa with similar distribution/dispersal patterns. The problem of the origin of Antarctic vascular plants is a perfect model for integration of modern methods of molecular phylogeography and phylogenetics, population biology, paleobiology and paleogeography for solving a long-standing enigma of historical plant geography and evolution.

Measurement of moss growth in continental Antarctica

Using steel pins inserted into growing moss colonies near Casey Station, Wilkes Land, continental Antarctica, we have measured the growth rate of three moss species: Bryum pseudotriquetrum and Schistidium antarctici over 20 years and Ceratodon purpureus over 10 years. This has provided the first long-term growth measurements for plants in Antarctica, confirming that moss shoots grow extremely slowly in Antarctica, elongating between 1 and 5 mm per year. Moss growth rates are dependent on availability of water. Antheridia were observed on some stems of B. pseudotriquetrum; no archegonia or sporophytes were observed. Stems bearing antheridia elongated much more slowly than vegetative stems in the same habitat. Two other methods of growth rate measurement were tested, and gave similar rates of elongation over shorter periods of time. However, for long-term measurements, the steel pin measurements proved remarkably reproducible and reliable.

Photosynthetic responses of selected Antarctic plants to solar radiation in the southern maritime Antarctic

The effects of UV-B exclusion and enhancement of solar radiation on photosynthesis of the two phanerogams which occur in the maritime Antarctic, Deschampsia antarctica and Colobanthus quitensis, and the moss Sanionia uncinats were investigated. Data on air temperature and solar radiation illustrate a drastic seasonal variation. Daily O3 column mean values and UV-B measured at ground level document the occurrence of the O3“hole” in the spring of 1997, with a concomitant increase in UV-B. The grass, D. antarctica, exhibited a broad temperature optimum for photosynthesis between 10–25°C while photosynthesis did not saturate even at high irradiance. The high water use efficiencies measured in the grass may be one of the features explaining the presence of this species in the maritime Antarctic. The net photosynthesis response to intercellular CO2 (A/ci) for D. antarctica was typical of a C3 plant. Exposure to a biologically effective UV-B irradiance of 0.74 W M-2 did not result in any significant change in either the maximum rate of photosynthesis at saturating CO2 and light, or in the initial carboxylation efficiency of Rubisco. (Vc,max). Furthermore while ambient (or enhanced) solar UV-B did not affect photochemical yield, measured in the field, of C. quitensis and D. antarctica, UV-B enhancement did affect negatively photochemical yield in S. uncinata. In D. antarctica plants, exposure to UV-B at low irradiances elicited increased flavonoid synthesis. The observed effects of UV-B enhancement on the moss (decreased photochemical yield) and the grass (increase in flavonoids) require further, separate investigation.

Photosynthetic responses of selected Antarctic plants to solar radiation in the southern maritime Antarctic

The effects of UV-B exclusion and enhancement of solar radiation on photosynthesis of the two phanerogams which occur in the maritime Antarctic, Deschampsia antarctica and Colobanthus quitensis, and the moss Sanionia uncinats were investigated. Data on air temperature and solar radiation illustrate a drastic seasonal variation. Daily O3 column mean values and UV-B measured at ground level document the occurrence of the O3“hole” in the spring of 1997, with a concomitant increase in UV-B. The grass, D. antarctica, exhibited a broad temperature optimum for photosynthesis between 10–25°C while photosynthesis did not saturate even at high irradiance. The high water use efficiencies measured in the grass may be one of the features explaining the presence of this species in the maritime Antarctic. The net photosynthesis response to intercellular CO2 (A/ci) for D. antarctica was typical of a C3 plant. Exposure to a biologically effective UV-B irradiance of 0.74 W M-2 did not result in any significant change in either the maximum rate of photosynthesis at saturating CO2 and light, or in the initial carboxylation efficiency of Rubisco. (Vc,max). Furthermore while ambient (or enhanced) solar UV-B did not affect photochemical yield, measured in the field, of C. quitensis and D. antarctica, UV-B enhancement did affect negatively photochemical yield in S. uncinata. In D. antarctica plants, exposure to UV-B at low irradiances elicited increased flavonoid synthesis. The observed effects of UV-B enhancement on the moss (decreased photochemical yield) and the grass (increase in flavonoids) require further, separate investigation.

Introduced plants in Antarctica: Potential impacts and conservation issues

The development of and compliance with the code of conduct embodied in the Antarctic Treaty to prevent or minimize the introduction of plants into the Antarctic is outlined. A chronological account of all known experimental and accidental introductions of higher plants in the field and their success and fate, if known, is given. The potential danger to the natural Antarctic ecosystem of importing plants rooted in their original soil is discussed with particular regard to the introduction of microorganisms, invertebrates and viable plant propagules. Unintentional dispersal of non-indigenous biota by human activities, and dispersal by natural agents (wind, birds) into and within the Antarctic, is assessed and numerous examples which contravened the measures of the Antarctic Treaty for the control of introduced biota are noted. The need for strict observance of the new Protocol on Environmental Protection to the Antarctic Treaty is emphasized.

Lipid content in leaves of Deschampsia antarctica from the maritime antarctic

Deschampsia antarctica plants were collected in Robert Island, Maritime Antarctica, and frozen in liquid nitrogen. Polar lipids and the composition of fatty acids in phospholipids and galactolipids were analysed in leaves and roots. Compared to other Gramineae, no unusual contents in polar lipids and in the degree of unsaturation of fatty acids in most lipid fractions were found. The highest unsaturation ratio (unsaturated/saturated fatty acids) of 3.3 was found in the phosphatidylinositol fraction. Although summer environmental temperatures in Robert Island are usually around 0°, leaves often reach higher temperatures, which are near their photosynthetic optimum.

Deschampsia antarctica E. Desv. plants with different chromosome number cultivated in vitro. Probabilistic relations of three adaptability indices with genome size

Aim. This work deals with probabilistic relations between genome size and adaptability indices research in 11 genotypes plants revealed among seeds of Deschampsia antarctica E. Desv. which has different genome size under standardized cultivation condition in vitro. Methods. We have used electrophoretic method for determination of protein relative contents in plant leaves, and statistical analysis for probabilistic relations determination. Results. Protein densitometric profiles for 11 D. antarctica genotypes plants were analyzed. Probabilistic scheme have been created for all researched plants genotypes for all previously analyzed parameters. Three probabilistic schemes of genotypes plants received from seeds collected in the same loci and season have been shown and analyzed. Conclusions. Protective protein densitometric profiles were similar for 11 genotypes of D. antarctica plants under standardized cultivation condition in vitro but quantitative part of protective protein has been changed. Genome size had an influence on its probabilistic relations with flavonoids content, leaf length and some protein relative contents in general pool. Probabilistic relations between genome size and some protein relative content and between the last and flavonoids content and leaf length is assumed to express underlying in this plants adaptation process to uniqueness nature condition in dynamic hereditary memory special information in certain degree. Mechanisms of probabilistic relations changes are required a detailed research.Keywords: Deschampsia antarctica, plants in vitro, probabilistic relations between genome size and adaptability indices, plant adaptability.

The Occurrence of Glossopteris in the Beacon Sandstone of Ferrar Glacier, South Victoria Land

The presence of members of the Glossopteris flora in Antarctica was first attested by the material collected from Mount Buckley by Dr. Wilson and Lieut. Bowers on Capt. Scott's last expedition to the South Pole. and the now famous specimens were described by Professor A. C. Seward (1914). Traces of fossil plants in Antarctica, were, however, first discovered by Mr. H. T. Ferrar, a member of the National Antarctic Expedition, 1901–1904, and were briefly described by Arber (1907), who reported, on some specimens from the Ferrar Glacier, that “several of these show fair-sized carbonaceous impressions or markings, which in all probability are of vegetable origin”. The evidence presented by this unpromising material did not “permit of any opinion as to the botanical nature or affinities of the fossils themselves, nor of the geological age of the beds in which they occur” (Arber, 1907, p. 48). Professor Seward examined the specimens and agreed with this conclusion (1914, p. 2).