Antarctica Plants Research Articles

Community assembly among potential invasive plants in Antarctica shaped by life history characteristics and climate warming

Community assembly among potential invasive plants in Antarctica shaped by life history characteristics and climate warming

Meta-analysis of root-associated bacterial communities of widely distributed native and invasive Poaceae plants in Antarctica

Meta-analysis of root-associated bacterial communities of widely distributed native and invasive Poaceae plants in Antarctica

Extreme environmental adaptation mechanisms of Antarctic bryophytes are mainly the activation of antioxidants, secondary metabolites and photosynthetic pathways

The environment in Antarctica is characterized by low temperature, intense UVB and few vegetation types. The Pohlia nutans M211 are bryophytes, which are the primary plants in Antarctica and can thrive well in the Antarctic harsh environment. The transcriptional profiling of Pohlia nutans M211 under low temperature and high UVB conditions was analyzed to explore their polar adaptation mechanism in the extreme Antarctic environment by third-generation sequencing and second-generation sequencing. In comparison to earlier second-generation sequencing techniques, a total of 43,101 non-redundant transcripts and 10,532 lncRNA transcripts were obtained, which were longer and more accurate. The analysis results of GO, KEGG, AS (alternative splicing), and WGCNA (weighted gene co-expression network analysis) of DEGs (differentially expressed genes), combined with the biochemical kits revealed that antioxidant, secondary metabolites pathways and photosynthesis were the key adaptive pathways for Pohlia nutans M211 to the Antarctic extreme environment. Furthermore, the low temperature and strong UVB are closely linked for the first time by the gene HY5 (hlongated hypocotyl 5) to form a protein interaction network through the PPI (protein–protein interaction networks) analysis method. The UVR8 module, photosynthetic module, secondary metabolites synthesis module, and temperature response module were the key components of the PPI network. In conclusion, this study will help to further explore the polar adaptation mechanism of Antarctic plants represented by bryophytes and to enrich the polar gene resources.

Nutrient availability regulates Deschampsia antarctica photosynthetic and stress tolerance performance in Antarctica.

Deschampsia antarctica is one of the only two native vascular plants in Antarctica, mostly located in the ice-free areas of the Peninsula's coast and adjacent islands. This region is characterized by a short growing season, frequent extreme climatic events, and soils with reduced nutrient availability. However, it is unknown whether its photosynthetic and stress tolerance mechanisms are affected by the availability of nutrients to deal with this particular environment. We studied the photosynthetic, primary metabolic, and stress tolerance performance of D. antarctica plants growing on three close sites (<500 m) with contrasting soil nutrient conditions. Plants from all sites showed similar photosynthetic rates, but mesophyll conductance and photobiochemistry were more limiting (~25%) in plants growing on low-nutrient availability soils. Additionally, these plants showed higher stress levels and larger investments in photoprotection and carbon pools, most probably driven by the need to stabilize proteins and membranes, and remodel cell walls. In contrast, when nutrients were readily available, plants shifted their carbon investment towards amino acids related to osmoprotection, growth, antioxidants, and polyamines, leading to vigorous plants without appreciable levels of stress. Taken together, these findings demonstrate that D. antarctica displays differential physiological performances to cope with adverse conditions depending on resource availability, allowing it to maximize stress tolerance without jeopardizing photosynthetic capacity.

Skua and plant dispersal: lessons from the Argentine Islands – Kyiv Peninsula region in the maritime Antarctic

Birds are one of the most likely dispersal vectors for plants in Antarctica. We studied the nesting behavior of south polar skua Catharacta maccormicki and brown skua Catharacta antarctica lonnbergi to assess their potential role in ornithochory in the Argentine Islands – Kyiv Peninsula region. Nest samples were collected during 2009–2020 years in the Argentine Islands – Kyiv Peninsula region including all islands and coasts of the Graham Land from the Lemaire Channel to the islands of Berthelot Islands from north to south and extending from west to east from the Roca Islands, Cruls Islands, Rasmussen Point to the coast. We found that skuas utilize different nest building materials, including bryophytes, vascular plants (hairgrass Deschampsia antarctica) and lichens. In south polar skua nests, mosses and lichens dominate in the nest material; in brown skuas Deschampsia antarctica and mosses dominate. Both bird species likely collect nest components from nearby vegetation formations (&lt; 1 m distant). We conclude that C. maccormicki and C. antarctica lonnbergi are not selective in their choice of plant species, simply using the materials that dominate near the nest. Therefore, both species carry these materials from nearby sites, and only occasionally bring them from distant places. In conclusion, for both species we did not find any evidence to support their involvement in long‐distance ornithochory (stomatochory) in the region.

Landscape Variables Influence over Active Restoration Strategies of Nothofagus Forests Degraded by Invasive Castor canadensis in Tierra del Fuego

North American beavers (Castor canadensis) are responsible for the major changes in the Tierra del Fuego Archipelago, altering riparian forests for the long-term. Passive restoration of the areas affected was ineffective in the medium-term (up to 20 years), being necessary active strategies. Plantations in abandoned ponds were made with Nothofagus pumilio and N. antarctica tree species across Tierra del Fuego island (Argentina). In the first experiment, we analysed the influence of biotic and abiotic factors in three micro-habitats in the impacted areas: front and tail of ponds, and cut not-flooded forest areas. Five-years-old N. pumilio seedlings had 39% survival in front, 21% in tails, and 46% in cut areas at year-3 of the restoration experiments, being negatively influenced by plant cover and soil moisture. Lower growth was recorded during year-1 (0.7–0.9 cm yr−1), but increased on time (1.9 cm yr−1 front, 1.6 cm yr−1 tail, 4.3 cm yr−1 cut areas). A second experiment explores the alternative to substitute the tree species to face the harder conditions of the impact and climate change. For this, we conducted a new plantation at four locations across the main bioclimatic zones, where 10–40 cm N. antarctica plants attained 17% survival in meadows (front and tail) and 30% in cut areas, being higher with larger than smaller plants (25% vs. 18%), and where they are mainly influenced by rainfall (4% in sites &lt;400 mm yr−1 and 41% in &gt;400 mm yr−1). The main damage was detected in the above-ground biomass due to dryness, but root survival allowed the emergence of new shoots in the following growing season. It is necessary to monitor different Nothofagus species across natural environments in the landscape to determine the feasibility and effectiveness of different strategies in restoration plans, considering the selection of climate-resilient tree species.

Composition and Radical Scavenging Activity of the Extracts from Deschampsia Antarctica É. Desv. Plants Grown in Situ and in Vitro

The work was aimed at studying the phytochemicals available in D. antarctica plants from various sites on Antarctic Islands, introducing the plants into in vitro culture and comparing the extracts from the plants grown in situ and in vitro. All the extracts were found to contain high amount of phenols, with luteolin and hydroxybenzoic acids derivatives being the main phytochemicals in the extracts from the plants grown in situ and in vitro. Being diluted by 10 times, the extracts scavenged 50÷90% of DPPH• radicals, 20÷40% of NO• radicals and 40÷60% of OH• radicals. Despite the differences in composition, extracts from the plants grown in situ and in vitro showed similar radical scavenging activity.

Symbiotic Interaction Enhances the Recovery of Endangered Tree Species in the Fragmented Maulino Forest.

Beneficial plant-associated microorganisms, such as fungal endophytes, are key partners that normally improve plant survival under different environmental stresses. It has been shown that microorganisms from extreme environments, like those associated with the roots of Antarctica plants, can be good partners to increase the performance of crop plants and to restore endangered native plants. Nothofagus alessandrii and N. glauca, are among the most endangered species of Chile, restricted to a narrow and/or limited distributional range associated mainly to the Maulino forest in Chile. Here we evaluated the effect of the inoculation with a fungal consortium of root endophytes isolated from the Antarctic host plant Colobanthus quitensis on the ecophysiological performance [photosynthesis, water use efficiency (WUE), and growth] of both endangered tree species. We also, tested how Antarctic root-fungal endophytes could affect the potential distribution of N. alessandrii through niche modeling. Additionally, we conducted a transplant experiment recording plant survival on 2 years in order to validate the model. Lastly, to evaluate if inoculation with Antarctic endophytes has negative impacts on native soil microorganisms, we compared the biodiversity of fungi and bacterial in the rhizospheric soil of transplanted individuals of N. alessandrii inoculated and non-inoculated with fungal endophytes. We found that inoculation with root-endophytes produced significant increases in N. alessandrii and N. glauca photosynthetic rates, water use efficiencies and cumulative growth. In N. alessandrii, seedling survival was significantly greater on inoculated plants compared with non-inoculated individuals. For this species, a spatial distribution modeling revealed that, inoculation with root-fungal endophytes could potentially increase the current distributional range by almost threefold. Inoculation with root-fungal endophytes, did not reduce native rhizospheric microbiome diversity. Our results suggest that the studied consortium of Antarctic root-fungal endophytes improve the ecophysiological performance as well as the survival of inoculated trees and can be used as a biotechnological tool for the restoration of endangered tree species.

Heat Shock Tolerance in Deschampsia antarctica Desv. Cultivated in vitro Is Mediated by Enzymatic and Non-enzymatic Antioxidants.

Deschampsia antarctica Desv, is the most successful colonizing species of a cold continent. In recent years due to climate change, the frequency of heat waves has increased in Antarctica, registering anomalous high temperatures during the summer of 2020. However, the populations of D. antarctica are responding positively to these events, increasing in number and size throughout the Antarctic Peninsula. In this work, the physiological and biochemical responses of D. antarctica plants grown in vitro (15 ± 1°C) and plants subjected to two heat shock treatments (23 and 35°C) were evaluated. The results obtained show that D. antarctica grown in vitro is capable of tolerating heat shock treatments; without showing visible damage to its morphology, or changes in its oxidative state and photosynthetic performance. These tolerance responses are primarily mediated by the efficient role of enzymatic and non-enzymatic antioxidant systems that maintain redox balance at higher temperatures. It is postulated that these mechanisms also operate in plants under natural conditions when exposed to environmental stresses.

Phenolic and flavonoid contents in Deschampsia antarctica plants growing in nature and cultured in vitro

Phenolic and flavonoid contents in Deschampsia antarctica plants growing in nature and cultured in vitro

Calculation of United Quality Latent Indices of Deschampsia antarctica plants adaptability of different origin grown in vitro

The research was to develop and describe in detail the algorithm for calculating the United Quality Latent Index (UQLI, Iq ) of plant adaptability from the collection of Deschampsia antarctica Ė. Desv. genotypes obtained from seeds collected at different sites in the Argentine Islands region, the maritime Antarctic, and grown in vitro at the laboratory conditions. Genome size and genetic distances by ISSR and IRAP markers according to data from published articles were used as basic indices of initial genetic heterogeneity for analyzed plant genotypes. To assess individual adaptability indices for eleven D. antarctica genotypes, we used measurement of the leaf length morphometric index and determination of the flavonoids content by rutin and the content of photosynthetic pigments. The spectra of reserve and protective proteins in leaves were investigated by polyacrylamide gel electrophoresis. To obtain the United Quality Latent Index of Adaptability (Iqi, UQLI), the method of extreme grouping was used. The estimation of Iqi (UQLI) was performed using pairwise comparisons of indices from differences sets for each pair of genotypes. We developed and described in detail the algorithm for Iqi estimation for eleven D. antarctica genotypes. As an example of application, correlation models of probability relations of the indices are presented. To evaluate the complex adaptability for eleven D. antarctica genotypes grown in vitro we used developed algorithm for the UQLI calculation. The individuality of the adaptive portrait for all studied genotypes under in vitro cultivation conditions was shown. The influence of basic genetic characteristics (genome size and genetic distances) on auxin metabolism-related indices of leaf length and flavonoid content was shown. Such effect may be carried out by genetic characteristics both individually and together, probably via auxin metabolism. Among the eight genotypes researched, we distinguish four different variants by correlation models and two (positive and negative) by the general Iqi value. Thus the Iqi (UQLI) is proposed to describe a large number of source data at different organization levels which characterize sample genotypes by reducing the dimensions to one dimensionless number. This genotypes’ individuality and the peculiarities of their grouping by Iqi should be taken into account when doing experimental studies using these genotypes as model plants, especially in experiments studying the regulation of productivity and the effect of the various exogenous factors, etc.

The content of phenolic compounds and flavonoids in in vitro plants and tissue culture of Deschampsia antarctica E. Desv.

Aim. The aim of the study was a comparative assessment of total phenolic content and total flavonoid content in in vitro plants, regenerated plants, plants grown in a growth chamber, and tissue culture of several genotypes of Deschampsia antarctica. Methods. In vitro culture, Folin-Ciocalteu method, spectrophotometry, high-performance liquid chromatography. Results. The total content of phenolic compounds and total flavonoid content was determined in the samples of three D. antarctica genotypes: G/D12-2a (2n=26), DAR12 (2n=26+0–3B) and Y66 (2n=36–39). The content of these biologically active compounds was the highest in in vitro plants and it was higher than in plants grown in a growth chamber. The highest content of BAC was found in DAR12 in vitro plants (16.50 mg of ferulic acid equivalent and 21.26 mg of rutin equivalent per g of dry weight, respectively). The regenerated plants did not differ significantly in the content of BAC from the original in vitro plants. In tissue culture, the content of BAC was lesser. One- and two-year-old tissue cultures did not differ significantly in the content of phenolic compounds and flavonoids. Conclusions. The relatively high content of phenolic compounds and flavonoids in in vitro plants and in regenerated plants indicates that in vitro cultivated D. antarctica plants can be a promising raw material for production of valuable BACs. Keywords: Deschampsia antarctica E. Desv., in vitro plants, plant tissue culture, phenolic compounds, flavonoids.

180 years of Botanical Investigations in Antarctica and the Role of Brazil

ABSTRACT Botany is one of the oldest sciences done above the 60oS parallel with more than 180 years passing since the first professional botanist collected plants in Antarctica. Far from being a barren place, plants constitute an important part of polar ecosystems. Brazil is one of only 29 countries in the world with consultative status and to currently develop botanical studies in Antarctica. We discuss the importance of polar science to Brazil and the role that Brazil has in the international austral-polar scientific community, as well as the importance of its newly inaugurated scientific station.

Effect of in vitro cold acclimation of Deschampsia antarctica on the accumulation of proteins with antifreeze activity.

Deschampsia antarctica has managed to colonize the maritime Antarctic. One of the main factors associated with its tolerance to low temperatures is the presence of apoplastic proteins with antifreeze activity. This work focuses on the effect of cold acclimation of D. antarctica on the accumulation of apoplastic proteins with antifreeze activity. Antifreeze proteins present in apoplastic extracts were purified by ice affinity purification, and their identity was determined by protein sequencing. D. antarctica plants were subjected to 22 days of cold acclimation at 4 °C. The highest content of apoplastic proteins with antifreeze activity was obtained at between 12 and 16 days of acclimation. Protein sequencing allowed their identification with >95% probability. Percentage coverage was 74% with D. antarctica ice recrystallization inhibition protein 1 (DaIRIP1) and 55% with DaIRIP3. Cold acclimation of D. antarctica improved the yield of apoplastic proteins, and resulted in an increase in the antifreeze activity of apoplastic extracts. An in silico analysis suggested that the fluctuations presented by the three-dimensional structures of DaIRIPs help to explain the presence of certain DaIRIPs in apoplastic extracts under the cold acclimation conditions evaluated.

Poaceae Type II Galactinol Synthase 2 from Antarctic Flowering Plant Deschampsia antarctica and Rice Improves Cold and Drought Tolerance by Accumulation of Raffinose Family Oligosaccharides in Transgenic Rice Plants.

Deschampsia antarctica is a Poaceae grass that has adapted to and colonized Antarctica. When D. antarctica plants were subjected to cold and dehydration stress both in the Antarctic field and in laboratory experiments, galactinol, a precursor of raffinose family oligosaccharides (RFOs) and raffinose were highly accumulated, which was accompanied by upregulation of galactinol synthase (GolS). The Poaceae monocots have a small family of GolS genes, which are divided into two distinct groups called types I and II. Type II GolSs are highly expanded in cold-adapted monocot plants. Transgenic rice plants, in which type II D. antarctica GolS2 (DaGolS2) and rice GolS2 (OsGolS2) were constitutively expressed, were markedly tolerant to cold and drought stress as compared to the wild-type rice plants. The RFO contents and GolS enzyme activities were higher in the DaGolS2- and OsGolS2-overexpressing progeny than in the wild-type plants under both normal and stress conditions. DaGolS2 and OsGolS2 overexpressors contained reduced levels of reactive oxygen species (ROS) relative to the wild-type plants after cold and drought treatments. Overall, these results suggest that Poaceae type II GolS2s play a conserved role in D. antarctica and rice in response to drought and cold stress by inducing the accumulation of RFO and decreasing ROS levels.

Callus formation and organogenesis in tissue culture Deschampsia antarctica E. Desv.

Aim. The aim of the work was to determine the optimal conditions for induction and proliferation of tissue culture obtained from D. antarctica plants from various localities of the Maritime Antarctica. Methods. Tissue and organ culture techniques. Results. The media В5 supplemented with 2 mg/l 2,4-D + 0,1 mg/l BAP, В5 supplemented with 10 mg/l 2,4-D + 0,2 mg/l BAP and МС, supplemented with 5 mg/l 2,4-D + 0,1 mg/l Kin were optimal for callus induction from different types of explants. The media with a reduced concentrations of auxins and cytokinins were the most effective for maintenance of continuous tissue culture compared to the media for callus induction: B5 + 2 mg/l 2,4-D mg/l + 0,1 mg/l BAP and MC + 1 mg/l 2,4-D + 0.1 mg/l Kin. Tissues from shoot growth point and leaf explants of genotypes DAR12a and G/D12-2a on medium B5 with 2 mg/l 2,4-D + 0.1 mg/l BAP and B5 with 10 mg/l 2,4-D + 0,2 mg/l BAP demonstrated the ability to spontaneous organogenesis and formed separate shoots. Conclusions. Conditions have been determined for the induction and proliferation of tissue culture from leaf, root, and shoot growth point explants of D. antarctica. The frequency of callus formation depended on the mineral composition of medium, ratios and concentrations of growth regulators, type of explant, and genotype of a donor-plant. As a result of spontaneous organogenesis, regenerated plants were obtained, conditions for their rooting in vitro were elaborated. The proposed methods for induction and proliferation tissue culture of D. antarctica in vitro can be used to produce the plant material useful for a various investigations. Keywords: Deschampsia antarctica E. Desv., tissue culture, organogenesis in vitro, frequency of callogenesis.

Positive interactions among native and invasive vascular plants in Antarctica: assessing the “nurse effect” at different spatial scales

Antarctica is a stressful ecosystem with few vascular plants, an ideal system to test positive interactions. Here, plants such as Deschampsia antarctica could generate more suitable micro-environmental conditions for the establishment of other plants (facilitation). We examined the co-occurrence of vascular plant species in the Antarctic Peninsula and assessed the potential nurse effect by D. antarctica on the native Colobanthus quitensis and the invasive Poa annua. We also measured the ecophysiological performance and survival of C. quitensis within and outside the canopy of D. antarctica in two study sites differing in stress levels. In addition, a survival experiment was conducted with the invasive Poa annua individuals within and outside D. antarctica individuals. In sites where present, target species co-occurred with D. antarctica in both Shetland Islands and Antarctic Peninsula. In agreement with the stress gradient hypothesis, we found evidence of facilitation between vascular Antarctic plant species. Specifically, we found that D. antarctica facilitates the native C. quitensis and the invasive P. annua and that the effect is stronger in more stressful sites. Additionally, C. quitensis distribution is compatible with an influence of either direct or indirect facilitation from D. antarctica. Facilitation between vascular plants may play a role structuring Antarctic plant communities. Thus, distribution of native species should be considered when assessing the introduction and spread of invasive species. Also, our results together with those from previous studies showed that the type and magnitude of biotic interactions may change with time and can depend on the plant traits considered.

Determination of the united quality latent index of adaptability (UQLIA) and contribution of some environmental parameters to it for Deschampsia antarctica populations, Galindez island (Maritime Antarctic) season 2017/2018

The purpose of our work has been to determine the indicator of complex adaptability — the United Quality Latent Index of Adaptability (UQLIA) for the experimental populations of Deschampsia antarctica É. Desv. and study the contribution to it of some environmental factors such as the near soil surface temperature and organogens content. Materials and methods. The determination of UQLIA was based on a pairwise comparison of the differences between investigated parameters of populations by mathematical regression techniques. The soil surface temperature was measured by loggers installed near plants in each locus during April 2017 – April 2018. Results and conclusions. Temperature fluctuations were described during December 2017 – February 2018 for twelve experimental populations of D. antarctica and one control fragment of moss turf subformation from Galindez Island. Significant variations in average daily near surface temperature were observed during the study period between populations, especially in December and January. The UQLIA of D. antarctica for this season was calculated on the basis of the projective cover, biometric indices of generative plants and the content of protective and reserve proteins in seeds for the eleven populations. The values of the United Soil Surface Temperature Influence Index (UTII) for the season summer months and the United Organogens Content in Soil Influence Index (UOCSII) have been calculated for the individual parameters of D. antarctica plants adaptability. The reliable contribution of UTII to ULIA has been shown for December and January, at the moment of the greatest variation of soil surface temperature. UOCSII provided a reliable contribution to the ULIA only in the amount of UTII. Keywords: Deschampsia antarctica, United Quality Latent Index of Adaptability (UQLIA), contribution of soil surface temperature and organogens content to complex adaptability.

Comprehensive characterization of cultivated in vitro Deschampsia antarctica E. Desv. plants with different chromosome numbers

D. antarctica E. Desv. plants cultivated in vitro were analyzed for the chromosome number, leaf length, and efficiency of callus formation. Most of the studied plants had a typical diploid chromosome number. However, a hypotriploid and a plant with B chromosomes demonstrated mixoploidy caused by the presence of a significant proportion (up to 15–25%) of aneuploid cells. Jaccard genetic distances between the plants determined from the data of ISSR- and IRAP-PCR analyses were within the range of 0.0323 to 0.1803. Furthermore, genetic distances between the specimens with atypical karyotype and diploids did not exceed the paired distances within the group of diploid plants. Variations in the leaf length and growth parameters of the plants were characterized. Plants with different chromosome numbers differed in the leaf length and efficiency of callus formation. Obtained results may indicate relationships between the chromosome number, studied morphometric parameters, and efficiency of callus formation in the analyzed D. antarctica plants.

Occurrence of arbuscular mycorrhizal fungi on King George Island, South Shetland Islands, Antarctica

Arbuscular mycorrhizal fungi make up an important ecological niche in ecosystems, and knowledge of their diversity in extreme environments is still incipient. The objective of this work was to evaluate the density and diversity of arbuscular mycorrhizal fungi in the soil of King George Island in the South Shetland Islands archipelago, Antarctica. For that, soil and roots of Deschampsia antarctica were collected at the brazilian research station in Antarctica. The spore density, species diversity and mycorrhizal colonization in the roots were evaluated. There was a low density of spores (27.4 ± 17.7) and root mycorrhizal colonization (6 ± 5.1%), which did not present statistical difference. Four species of arbuscular mycorrhizal fungi were identified, distributed in two genera: three species of the genus Glomus (Glomus sp1, Glomus sp2 and Glomus sp3) and one of the genus Acaulospora, which was identified at species level (Acaulospora mellea). Greater soil diversity was verified with pH 5.9 and phosphorus concentration of 111 mg dm-3, occurring two species of genus Glomus and A. mellea. Based on literature data, this may be the first record of this species of Acaulospora mellea in Antarctic soils, colonizing D. antarctica plants.