Aster Amellus Research Articles

First Report of Golovinomyces sp. (Euoidium sp.) Causing Powdery Mildew on Aster amellus L. in India

First Report of Golovinomyces sp. (Euoidium sp.) Causing Powdery Mildew on Aster amellus L. in India

×Asterron, nom. nov., a replacement name for ×Asterigeron Tzvelev, and ×Asterron ucrainicus, comb. nov.

In 1994 Tzvelev described ×Asterigeron ucrainicus Tzvelev, which he interpreted as a hybrid of Aster amellus L. and Erigeron acris L., and thus established a nothogenus ×Asterigeron Tzvelev (Aster L. × Erigeron L.). However, the name ×Asterigeron Tzvelev is a later homonym of Asterigeron Rydb.; because of that a new replacement name, ×Asterron Olshanskyi, is proposed for this nothogenus. Also, the new nomenclatural combination ×Asterron ucrainicus (Tzvelev) Olshanskyi (≡ ×Asterigeron ucrainicus Tzvelev) is validated.

Biomonitoring of Post-Mine Environment Using Ruderal Plants

Ruderal plants that remove toxic metals by accumulating in their tissues are called accumulators. Such accumulators can be used for phytoremediation or phytomining. The use of plants for biomonitoring environmental pollution by a non-invasive monitoring method correlates the effects of anthropogenic factors and living organisms. The advantage is the early detection of changes in the environment, thanks to the rapid response of bioindicators, responding to changes in the habitat, for example, by creating deformations. At present, biomonitoring is one of the indispensable parts of nature and environmental protection. The following species were selected for research - Aster amellus L., Rosa canina L. and Paraleucobryum longifolium; the area of ​​interest was the post-mining area. The aim of the study was to verify the hyperaccumulation activity of ruderal plants on the thermally active dump pile Ema, in the district of Ostrava-Karviná, Czech Republic. The plant samples were taken in the places with the thermal activity and were compared as for the capacity of bioaccumulation of hazardous metals – Co, Mo, Cd, Pb, Cr, As, Ba, Sr in the plant tissues from different parts of the plants (root, stem, leaf, fruit). The results were compared with the collection of metals at sampling points. The highest ability to bioaccumulate was demonstrated by plants from the Bryophyta division. Keywords: Bioavailability; Ema dump pile; Hyperaccumulation; Plants; Toxic metals.

Thirty-two new and noteworthy floristic records from north-eastern Greece.

BackgroundThe vascular flora of Greece comprises no less than 6,705 vascular plant taxa (species and subspecies, including established aliens) in an area of 131,957 km2. The phytogeographic region of north-east Greece (NE), an area characterised by physiographic diversity, is the richest floristic region in Greece, yet it remains less-explored compared to other regions.New informationWe present an annotated inventory of 32 vascular plant taxa collected predominantly from the East Macedonia and Thrace Regions (Makedonia and Thraki, NE Greece), following fieldwork that took place between 2013 and 2021. In our results, we identify seven new additions to the Greek flora (Aethionemasaxatilesubsp.rhodopaeum, Anthericumramosum, Asteramellus, Euphorbiacarniolica, Hesperismatronalissubsp.matronalis, Saponariastranjensis and Silenefetlerii) and 25 new records to the regional Greek flora consisting of mostly rare Balkan endemics of a restricted distribution and presumable conservation priorities. Taxonomic comments are added, where necessary. IUCN threat categories are assigned to certain taxa. Our investigation highlights the importance of the Balkan border areas as a source of new floristic elements for single countries and points to the importance of range-restricted taxa, in addition to single-country endemics, to address plants with a narrow distribution pattern.

Phytorarity of Chernihiv region in M. M. Gryshko National Botanical Garden of the NAS of Ukraine

Increasing anthropogenic pressure, global climate change, and the lack of large introduction centers in the Chernihiv region makes it important to preserve rare species of flora ex situ outside this administrative region. The article presents the results of the study of taxonomic composition and evaluation of the success of the introduction of rare plant species of Chernihiv region in the M. M. Gryshko National Botanical Garden of National Academy of Sciences of Ukraine. The study of rare plant species and the development of methods for their effective reproduction was initiated in the NBG in 1970 in a separate section “Rare plants of the flora of Ukraine.” It is established that the collection grows and protects 57 phythorarites of Chernihiv region, of which 29 species are listed in the Red Book of Ukraine (III edition), and 28 species – in the “List of regionally rare plant species of Chernihiv region”. Most plants successfully recover ex situ with moderate care or without additional human intervention. The biomorphological spectrum of introduced plants is dominated by cryptophytes (50.88 %) and hemicryptophytes (42.11 %), the shares of phanerophytes, hamephytes and therophytes are insignificant. 17 species of phythorarites formed stable homeostatic populations. Of these: 5 species are listed in the Red Book of Ukraine (Allium ursinum, Crocus reticulatus, Epipactis helleborine, Galanthus nivalis, Pulsatilla pratensis) and 12 species – in the “List of regionally rare plant species of Chernihiv region” (Aster amellus, Corydalis intermedia, C. marschal, Daphne mesereum, Equisetum hyemale, Iris hungarica, Phlomis tuberosa, Primula veris, Pteridium aquilinum, Scilla bifolia, S. sibirica, Vinca minor). Thus, the cultivation of almost a third of the phythorarites of Chernihiv region in the M. M. Gryshko National Botanical Garden testifies to the effectiveness of their preservation ex situ.

Floristic transformation of the steppe area in the lower reaches of the Osyotr River due to anthropogenic impact

The purpose of this study was to survey the steppe site located on the right bank of the Osyotr River, near the village of Argunovo, in the urban district of Zaraysk, Moscow Region. It was required to analyze the key floristic changes that have occurred in its composition to date. For comparison, the floristic description of this site, detailed by R.I. Dyakova in the 1950s. The work takes into account the fact of man-made interference in the 1960s, as a result of limestone mining there in violation of the vegetation cover. In the autumn, 2020 the authors of this article studied a steppe site in the neighborhoods of the village of Argunovo in Zaraisk urban district of Moscow region and collected a herbarium donated to funds [MHA]. This steppe community was first discovered and described in detail by R.I. Dyakova in the 1950s. In the 20th century, due to the extraction of limestone in the lower reaches of the Osyotr River, this biotope was disturbed. It was established that over the past 70 years, the area occupied by the association with Stipa pennata L. and Geranium sanguineum L. significantly decreased and some steppe species disappeared. A factor in the transformation of the steppe cenosis was also cessation of grazing, which led to the appearance of a number of meadow-steppe species. The studied area near the village of Argunovo can be considered as a unique meadow-steppe reserve. It is located at the northern border of the forest-steppe zone and includes the elements of the Oka steppe flora that has preserved to this day. The populations of rare and protected species have been preserved: Stipa pennata, Aster amellus L., Campanula bononiensis L., Gentiana cruciata L., Rosa villosa L. and Pyrus communis L., included in the Red Data Book of Moscow Region. The studied area is potentially susceptible to the invasion of alien species (Heracleum sosnowskyi Manden, Acer negundo L.) and needs monitoring and protection at the level of the community, population and each species.

Differences in iron acquisition strategies of calcicole plant species from xerothermic grasslands

Little is known about iron (Fe) acquisition of calcicole species from xerothermic grasslands and their resistance to Fe-dependent chlorosis. In this study an experiment was designed to investigate effects of opposing soil types (acidic Podzol vs slightly alkaline Rendzina) and addition of HBED-chelated Fe (five doses of 5 and 25 μmol kg−1 soil every two weeks). Selected calcicole plant species occurring on xerothermic grasslands, Aster amellus L. (Aa), Betonica officinalis L. (Bo), Prunella grandiflora (L.) Scholler (Pg), Salvia verticillata L. (Sv) and Veronica teucrium L. (Vt), were tested in a pot experiment under field conditions. Responses of plants were described using measurements of chlorosis, growth, chlorophyll content and fluorescence, activity of antioxidant enzymes and content of elements, including Ca, Mg, Fe, Mn, Zn and Cu. Some Podzol-grown plants showed arrested growth (up to 80% significant reduction of root and shoot fresh weight (FW) compared to Rendzina-grown plant, depending on species) but no signs of Fe-dependent chlorosis, whereas the same species grown on Rendzina performed very differentially. Lime chlorosis on Rendzina was induced in Aa, Bo and Pg (c.a. 30–40% significant reduction of chlorophyll content compared to Fe-supplied plants) but not in Sv and Vt. Fe-HBED treatment totally diminished chlorosis in species-dependent dose (5 μmol kg−1 soil for Aa and Pg and 25 μmol kg−1 soil for Bo) but significantly slowed growth (up to 50% significant reduction of root FW and 65% reduction of shoot FW compared to non-Fe-treated Rendzina-grown plant, depending on species). Chlorosis negatively affected functioning of photosynthetic apparatus alternating quantum yield of primary PSII photochemistry (FV/FM), light energy dissipation (DI0/RC) and performance index (PIABS) and Fe-HBED significantly alleviated these perturbations. Activity of antioxidant enzymes suggested Fe-HBED-caused alleviation of oxidative stress. Reduction of chlorosis did not rely on improved Fe accumulation, nor on altered partitioning on root-shoot axis, but a relation between chlorosis and manganese (Mn) in roots was observed. The results seem to indicate more complex interaction between Fe and Mn in induction of soil-dependent chlorosis than one might expect. Availability of Fe on the slightly alkaline soil limited functioning of the studied calcicole species in specific manner and probably created micro habitats. Ultimately, it can be clearly seen that xerothermic grasslands are composed of chlorosis-resistant and chlorosis-susceptible species.

Unmasking cryptic biodiversity in polyploids: origin and diversification of Aster amellus aggregate.

The origin of different cytotypes by autopolyploidy may be an important mechanism in plant diversification. Although cryptic autopolyploids probably comprise the largest fraction of overlooked plant diversity, our knowledge of their origin and evolution is still rather limited. Here we study the presumed autopolyploid aggregate of Aster amellus, which encompasses diploid and hexaploid cytotypes. Although the cytotypes of A. amellus are not morphologically distinguishable, previous studies showed spatial segregation and limited gene flow between them, which could result in different evolutionary trajectories for each cytotype. We combine macroevolutionary, microevolutionary and niche modelling tools to disentangle the origin and the demographic history of the cytotypes, using chloroplast and nuclear markers in a dense population sampling in central Europe. Our results revealed a segregation between diploid and hexaploid cytotypes in the nuclear genome, where each cytotype represents a monophyletic lineage probably homogenized by concerted evolution. In contrast, the chloroplast genome showed intermixed connections between the cytotypes, which may correspond to shared ancestral relationships. Phylogeny, demographic analyses and ecological niche modelling supported an ongoing differentiation of the cytotypes, where the hexaploid cytotype is experiencing a demographic expansion and niche differentiation with respect to its diploid relative. The two cytotypes may be considered as two different lineages at the onset of their evolutionary diversification. Polyploidization led to the occurrence of hexaploids, which expanded and changed their ecological niche.

In situ phytoremediation of dyes from textile wastewater using garden ornamental plants, effect on soil quality and plant growth

In situ phytoremediation of dyes from textile wastewater was carried out in a high rate transpiration system ridges (91.4 m × 1.0 m) cultivated independently with Tagetes patula, Aster amellus, Portulaca grandiflora and Gaillardia grandiflora which reduced American Dye Manufacturers Institute color value by 59, 50, 46 and 73%, respectively within 30 d compared to dye accumulated in unplanted ridges. Significant increase in microbial count and electric conductivity of soil was observed during phytoremediation. Reduction in the contents of macro (N, P, K and C), micro (B, Cu, Fe and Mn) elements and heavy metals (Cd, As, Pb and Cr) was observed in the soil from planted ridges due to phyto-treatment. Root tissues of these plants showed significant increase in the specific activities of oxido-reductive enzymes such as lignin peroxidase, laccase, veratryl alcohol oxidase, tyrosinase and azo reductase during decolorization of textile dyes from soil. Anatomical studies of plants roots revealed the occurrence of textile dyes in tissues and subsequent degradation. A minor decrease in plant growth was also observed. Overall surveillance suggests that the use of garden ornamental plants on the ridges of constructed wetland for the treatment of dyes from wastewater along with the consortia of soil microbial flora is a wise and aesthetically pleasant strategy.

Sozological peculiarities of the flora of the Desna Plateau (Ukraine)

According to the goals and objectives of the Global Strategy for Plant Conservation for 2011–2020 studying and monitoring the rare component of regional floras is highly relevant. This article presents the results of a nature conservation study of the flora of the Desna Plateau (Кrolevets’ and Hlukhiv geobotanic region), situated in the northeast part of Ukraine at the border line of two geomorphological regions (the Central Russian Upland and the Polesia-Dnipro lowland) and of two physical-geographical zones (Novhorod-Sivers`ke Polesia and the Sums`ky forest-steppe. In the orographic aspect, the territory is made up of the western spurs of the Central Russian Upland with the dissectioned forms of the relief. The studied area consists of about 4000 km2. Field route studies aimed at compiling floral lists, geobotanical description and herbarizing were conducted in the period 2002–2016. Separate sites of nature conservation interest were re-examined in different seasonal periods. The basis of the annotated summary of the rare species of vascular plant flora is made up by the materials of original research, as well as herbarium (KW) and literary reviews. The complex floristic analysis of the rare component of the regional flora was carried out in cameral conditions, which made it possible to identify the systematic, geographical, ecological, phytocenological and nature conservation structures of the rare species of vascular plant flora in the investigated area. According to the data received, the total number of species of vascular plants endangered by anthropogenic impact is composed of 85 species belonging to 32 families, 54 genera. Among the families, the following predominate: Orchidaceae (14 genera), Asteraceae, Ranunculaceae (8 genera in each), Iridaceae (5), Aspidiaceae, Cyperaceae (4 genera in each). Among the genera, the following predominate – Carex (4 species); Dryopteris, Orchis, Iris, Jurinea – 3 species in each. It was concluded that among the rare species there are plant species of different physical and geographical zones and this corresponds to the ecotone location of the region. Among species at the edge of their range, 14 are on the extreme northern border of their typical range (Linum flavum L., Carex rhizina Blytt ex Lindb., Centaurea ruthenica Lam., Trinia multicaulis Schishk, Aster amellus L., Galatella linosyris (L.) Rchb. f., Stipa tirsa Steven), 7 species are found on the southern border of their range (Cypripedium calceolus L., Pedicularis sceptrum-carolinum L., Parnassia palustris L., Lycopodium annotinum L., 4 species (Anemone nemorosa L., Salix myrsinifolia Salisb., Galanthus nivalis L., Gladiolus imbricatus L. are found on the eastern border of their distribution. The nature conservation structure includes 4 species from the Bern Convention on the Conservation of European Wildlife and Natural Habitats (Dracocephalum ruyschiana L., Pulsatilla patens (L.) Mill s.l., Salvinia natans L., Ostericum palustre (Bess) Bess); 3 species from the supplement to the CITES Convention (Adonis vernalis L., Cypripedium calceolus L., Orchis militaris L.), 27 species from the Red Book of Ukraine (Lilium martagon L., Allium ursinum L., Neottia nidus-avis (L.) Rich, Stipa pennata L.), 49 species from Sumy region rare species list (Clematis recta L., Pulsatilla patens (L.) Mill., Eremogone saxatilis (L.) Ikonn., Drosera rotundifolia L., Pedicularis kaufmannii Pinzg., Carex limosa L., C. umbrosa Host.). In addition, we suggest including into this list Sanquisorba officinalis L., Briza media L., Beckmania eruciformis (L.) Host., Melica nutans L., Coronilla varia L., Salvia nutans L., Scilla siberica Haw., Corydalis solida (L.) Clairv., Valeriana officinalis L., Vincetoxicum hirundinaria Medic., Menyanthes trifoliata L., Hesperis matronalis L., Naumburgia thyrsiflora (L.) Rchb., Thalictrum aquilegifolium L., T. minus L., Verbascum nigrum L., Polygonatum multiflorum (L.) All. It was found that among the rare species of the region mesophytes predominate and they are confined to meadow and forest habitats. To a lesser extent, xeromesophytes and xerophytes of meadow-steppe, as well as hygrophytes and hydrophytes of shoreline and water habitats are represented. The nature reserve fund of the region was analyzed according to the methodology of assessing the nature reserves by botanical value priority criteria. To optimize the region's nature reserve fund, a rationale for creating a landscape reserve of local significance “Zvenyhorods'ky” with a total area of 2,000 hectares was compiled, giving it the status of a regional biodiversity centre.

Нові знахідки у флорі міст Північного Приазов’я

<p>Northern Azov is unique region in origin and conditions, which modern flora developed in conditions of active human economic activities. Anthropogenic transformations have resulted to changes in vegetation cover and wild plant communities are transformed into synanthropic floral complexes.</p><p>The results achieved through our expeditionary studies conducted in 2013-2016 in the Northern Azov (in the administrative boundaries of the cities Berdyansk, Primorsk (Zaporizhia region), and Genichesk (Kherson region). In total, we founded new locations for 25 vascular plants: <em>Armoracia rusticana</em> P.G. Gaertn., B. Mey. & Scherb., <em>Apium graveolens</em><strong> </strong>L., <em>Arabis</em><em> </em><em>recta</em><em> </em>Vill., <em>Aster amellus</em><strong> </strong>L., <em>Acalypha australis L.</em>, <em>Mahonia aquifolium</em> (Pursh) Nutt., <em>Oxybaphus</em><em> </em><em>nyctagineus</em> (Michx.) Sweet, <em>Bidens</em><em> </em><em>frondosa</em>. L., <em>Ipomoea purpurea</em><strong> (</strong>L.), <em>Sedum acre</em> L., <em>Clematis vitalba</em> L., <em>Scilla</em><em> </em><em>siberica</em> Haw., <em>Zea majus</em> L., <em>Philadelphus</em><em> </em><em>coronarius</em> L., <em>Robinia</em><em> </em><em>viscosa</em> Vent., <em>Fagopyrum esculentum</em> Moench, <em>Nigella damascena</em> L., <em>Convallaria</em><em> </em><em>majalis</em> L., <em>Rubus anatolicus</em> (Focke) Focke ex Hausskn., <em>Ricinus</em><em> </em><em>communis</em> L., <em>Lablab</em><em> </em><em>purpureus</em> L., <em>Chrysanthemum segetum</em> L., <em>Gaillardia pulchella</em> Foug., <em>Antirrhinum majus</em> L., Tagetes patula L. In addition, we provided a brief description of their habitats and described new locations for new and previously marked aboriginal, alien, and cultivated plants that are capable of savagery for Northern Azov flora. Among all annotated species the significant proportion are the alien species that fall out of cultivation.</p>

Taxonomic status ofAster, GalatellaandTripolium(Asteraceae) in view of anatomical and micro-morphological evidence

Using light and scanning electron microscopy (SEM), comparative analyses of anatomical and micro-morphological characteristics of the leaf, stem and peduncle have been carried out on five species of the family Asteraceae (Aster amellus, Galatella linosyris, G. cana, G. sedifolia and Tripolium pannonicum), previously included in Aster although more recent morphological and phylogenetic studies indicate that Galatella and Tripolium should be considered as separate genera. The aim of the present study was to establish whether these species could be differentiated by anatomical characters. Our results will further inform the decision to separate the four aforementioned species from the genus Aster, as well as indicate whether anatomical data confirm the proposed circumscription of the genera Galatella and Tripolium. The anatomical observations and data analyses using discriminant and correspondence analysis showed that the combination of selected qualitative and quantitative characters separated the species into three groups, corresponding to the three genera. The characters of the leaf blade, its epidermis in particular, proved to be of the highest significance for discrimination at generic rank. The specific qualitative features that characterize each of the species and the genera were emphasized. Our findings support the attribution of the examined species to three genera, which proved to be anatomically distinguishable and well defined.

Mycorrhizal Symbiosis and Local Adaptation in Aster amellus: A Field Transplant Experiment

Many plant populations have adapted to local soil conditions. However, the role of arbuscular mycorrhizal fungi is often overlooked in this context. Only a few studies have used reciprocal transplant experiments to study the relationships between soil conditions, mycorrhizal colonisation and plant growth. Furthermore, most of the studies were conducted under controlled greenhouse conditions. However, long-term field experiments can provide more realistic insights into this issue. We conducted a five-year field reciprocal transplant experiment to study the relationships between soil conditions, arbuscular mycorrhizal fungi and plant growth in the obligate mycotrophic herb Aster amellus. We conducted this study in two regions in the Czech Republic that differ significantly in their soil nutrient content, namely Czech Karst (region K) and Ceske Stredohori (region S). Plants that originated from region S had significantly higher mycorrhizal colonisation than plants from region K, indicating that the percentage of mycorrhizal colonisation has a genetic basis. We found no evidence of local adaptation in Aster amellus. Instead, plants from region S outperformed the plants from region K in both target regions. Similarly, plants from region S showed more mycorrhizal colonisation in all cases, which was likely driven by the lower nutrient content in the soil from that region. Thus, plant aboveground biomass and mycorrhizal colonisation exhibited corresponding differences between the two target regions and regions of origin. Higher mycorrhizal colonisation in the plants from region with lower soil nutrient content (region S) in both target regions indicates that mycorrhizal colonisation is an adaptive trait. However, lower aboveground biomass in the plants with lower mycorrhizal colonisation suggests that the plants from region K are in fact maladapted by their low inherent mycorrhizal colonization. We conclude that including mycorrhizal symbiosis in local adaptation studies may increase our understanding of the mechanisms by which plants adapt to their environment.

Co-Adaptation of Plants and Communities of Arbuscular Mycorrhizal Fungi to Their Soil Conditions

The co-adaptation model formulated on the basis of the reciprocal interaction among plants, arbuscular mycorrhizal fungi (AMF) and soil hypothesizes that plants are adapted to their native AMF. Studies focused on this adaptation bring inconsistent results, however. Previously, we showed that different genotypes of Aster amellus exhibit different percentages of root colonization and that the species is adapted to the abiotic-soil environment combined with its native AMF isolate, but not to a specific AMF isolate alone. Here we asked whether plant populations of A. amellus are adapted to the whole native AMF community and whether there is co-adaptation between plants growing in their native soil and the native AMF community. In the first experiment, we used plants of one population of A. amellus from a marl region and plants of one population from a limestone region and planted them in non-sterile soil from both regions in a full factorial design. In the second experiment, plants from both regions were grown in their native sterilized soil and inoculated with their native AMF community or with the AMF community from the second region. Plants from each region established a specific level of root colonization, and AMF from each region formed a specific abundance of particular morphological structures in A. amellus roots. While we did not find any evidence that the plants are adapted to their whole-soil environment in terms of their growth, we did find evidence that adaptation of plants to native soil conditions could occur via adaptation of AMF to their native soil and plants and association of plants with specific type of AMF colonization. This type of adaptation could lead to the absence of adaptation in terms of plant growth.

Intraspecific ploidy variation: A hidden, minor player in plant–soil–mycorrhizal fungi interactions

Genome duplication and arbuscular mycorrhizal (AM) symbiosis are ubiquitous in angiosperms. While the significance of each of these phenomena separately has been intensively studied, their interaction remains to be understood. Three diploid and three hexaploid populations of Aster amellus (Asteraceae) were characterized in terms of the soil conditions in situ and mycorrhizal root colonization. In a greenhouse experiment, the effects of ploidy level, substrate conditions, and AM fungi on plant performance were then separated by growing noninoculated plants or plants inoculated with AM fungi in substrates native to either the diploids or hexaploids. The diploids inhabited nutritionally richer sites but did not differ from hexaploid plants in the level of mycorrhizal root colonization in situ. In the experiment, hexaploids generally performed better than the diploids. This intercytotype growth difference was enhanced by soil fertility, with hexaploids benefiting more from nutritionally richer substrate than the diploids. AM inoculation was crucial for plant growth and phosphorus uptake. The interaction between ploidy level and AM inoculation significantly influenced only dry mass of roots, phosphorus concentrations in shoot biomass, and the length of the extraradical mycelium in the nonsterile substrates. Our results support the idea that polyploidy can affect the mycorrhizal growth response of host plants. Nevertheless, the effects of the interaction between ploidy and inoculation were weaker than the main effects of these factors.

Effect of Plant Growth Regulators on Growth and Yield of Daisy (Aster amellus L.) Cv. Dwarf Pink

An experiment was carried out to improve plant stature in daisy (Aster amellus L.) cv. Dwarf Pink using various growth regulators. Among the various growth promoters and their combinations tested, gibberellic acid (150ppm) and brassinosteroid (0.5ppm) application produced maximum vegetative growth, spike yield and vase-life. It is concluded that a combination of gibberellic acid (150ppm) and BR (0.5ppm) is helpful improving growth and quality in daisy cv. Dwarf Pink.

The Effect of AMF Suppression on Plant Species Composition in a Nutrient-Poor Dry Grassland

Arbuscular mycorrhizal fungi (AMF) are expected to be one of the key drivers determining the diversity of natural plant communities, especially in nutrient-poor and dry habitats. Several previous studies have explored the importance of AMF for the composition of plant communities in various types of habitats. Surprisingly, studies of the role of AMF in nutrient-poor dry grassland communities dominated by less mycotrophic plant species are still relatively rare. We present the results of a 3-year study in which a plant community in a species-rich dry grassland was subjected to the fungicide carbendazim to suppress AMF colonization. We tested the effect of the fungicide on the following parameters: the plant species composition; the number of plant species; the cover of the rare, highly mycorrhiza-dependent species Aster amellus; the cover of the dominant, less mycorrhiza-dependent species Brachypodium pinnatum; and the cover of graminoids and perennial forbs. In addition, we examined the mycorrhizal inoculation potential of the soil. We found that the suppression of AMF with fungicide resulted in substantial changes in plant species composition and significant decrease in species richness, the cover of A. amellus and the cover of perennial forbs. In contrast the species increasing their cover after fungicide application were graminoids—the C3 grasses B. pinnatum and Bromus erectus and the sedge Carex flacca. These species appear to be less mycorrhiza dependent. Moreover, due to their clonal growth and efficient nutrient usage, they are, most likely, better competitors than perennial forbs under fungicide application. Our results thus suggest that AMF are an essential part of the soil communities supporting a high diversity of plant species in species-rich dry grasslands in nutrient-poor habitats. The AMF are especially important for the maintenance of the populations of perennial forbs, many of which are rare and endangered in the area.

Absence of gene flow between diploids and hexaploids of Aster amellus at multiple spatial scales

The potential for gene exchange across ploidy levels has long been recognized, but only a few studies have explored the rate of gene flow among different cytotypes. In addition, most of the existing knowledge comes from contact zones between diploids and tetraploids. The purpose of this paper was to investigate relationships between diploid and hexaploid individuals within the Aster amellus aggregate. A. amellus is known to occur in diploid and hexaploid cytotypes in Europe, with a complex contact zone in central Europe. Patterns of genetic diversity were investigated using seven microsatellite loci at three different spatial scales: (1) in the single known mixed-ploidy population; (2) in populations at the contact zone and (3) in a wider range of populations across Europe. The results show clear separation of the cytotypes at all three spatial scales. In addition, analysis of molecular variance strongly supported a model predicting a single origin of the hexaploids, with no or very limited gene flow between the cytotypes. Some hexaploid individuals found in the mixed-ploidy population, however, fell into the diploid cluster. This could suggest recurrent polyploid formation or occasional cross-pollination between cytotypes; however, there are strong post-zygotic breeding barriers between the two cytotypes, making the latter less plausible. Overall, the results suggest that the cytotypes could represent two cryptic species. Nevertheless, their formal separation is difficult as they cannot be distinguished morphologically, occupy very similar habitat conditions and have largely overlapping distribution ranges. These results show that polyploid complexes must be treated with caution as they can hide biological diversity and can have different adaptation potentials, evolving independently.

Cytotype distribution at a diploid-hexaploid contact zone in Aster amellus (Asteraceae).

The present study aims to assess the diversity and distribution of cytotypes of Aster amellus in central and eastern Europe, contributing with data to improve understanding of the evolutionary dynamics of the contact zone between diploids and hexaploids of this polyploid complex. Large-scale cytotype screening of 4720 individuals collected in 229 populations was performed using 4',6-diamidino-2-phenylindole (DAPI) flow cytometry. Fine-scale cytotype screening was performed in the mixed-ploidy population. Reproductive variables, such as number of florets per flower head, seed set and seedling emergence, as well as ploidy level of seeds and seedlings were recorded in this population. The diploid-hexaploid contact zone is large and complex, reaching the Czech Republic in the west, Austria in the south, Poland in the north-east and Romania in the extreme east of the surveyed areas. Most populations presented only one cytotype, either diploid or hexaploid. In several areas of the contact zone both cytotypes were found to grow in parapatry. One mixed-ploidy population of diploids and hexaploids was detected for the first time, but no signs of hybridization were detected. In this population, diploids had a significantly lower reproductive success, and significantly higher production of intercytotype offspring, being in reproductive disadvantage in comparison with hexaploids. The contact zone of diploid and hexaploid A. amellus in central and eastern Europe seems to be highly dynamic and diffuse, with both primary and secondary contacts being possible. The obtained results suggest the origin of hexaploids through diploids, overall supporting previous hypotheses that this species is autopolyploid. Data from the only mixed-ploidy population detected so far suggest that the minority cytotype exclusion is an important evolutionary mechanisms driving the prevalence of single-cytotype populations, and thus contributing to the current distributional patterns of the cytotypes of A. amellus.

Linear landscape elements in an Austrian viticultural landscape have limited effects on spatial patterns of plant genetic diversity

Background: The Wachau region along the river Danube in eastern Austria represents one of central Europe's hotspots of plant and animal species diversity. One of the typical landscape elements is vineyards, mostly established as linear elements on terraces along the slopes, with a characteristic and species-rich flora and fauna on terrace slopes lying between the cultivated terraces. Aims: We addressed the question of how the genetic variation of four plant species of open grassland vegetation types is distributed. We asked if levels and distribution of genetic diversity of the plant species Aster amellus, Gentianella aspera, Pulsatilla grandis, and Stachys recta were correlated with geographic distances along the terrace slopes. Methods: The dominant inherited molecular marker system random amplified polymorphic DNA (RAPD ) was used to estimate and compare the distribution of genetic diversity of the four selected species. Results: We found only low levels of correlation of the distribution of genetic variation with linear geographic patterns and obtained indirect evidence for high levels of gene flow between adjacent terrace slopes. Conclusions: We found that genetic diversity parameters of the four target species did not mirror the pattern of linear landscape elements, indicating that gene flow acts efficiently against the linear distribution of genetic variation.