Hypochaeris Radicata Research Articles

Multiple introductions of divergent lineages and admixture conferred the high invasiveness in a widespread weed (Hypochaeris radicata).

Biological invasion consists of spatially and temporally varying stages, accompanied by ecological and evolutionary changes. Understanding the genomics underlying invasion dynamics provides critical insights into the geographic sources and genetic diversity, contributing to successful invasions across space and time. Here, we used genomic data and model-based approaches to characterize the invasion dynamics of Hypochaeris radicata L., a noxious weed in Korea. Genetic diversity and assignment patterns were investigated using 3563 SNPs of 283 individuals sampled from 22 populations. We employed a coalescent-based simulation method to estimate demographic changes for each population and inferred colonization history using both phylogenetic and population genetic model-based approaches. Our data suggest that H. radicata has been repeatedly been introduced to Korea from multiple genetic sources within the last 50 years, experiencing weak population bottlenecks followed by subsequent population expansions. These findings highlight the potential for further range expansion, particularly in the presence of human-mediated dispersal. Our study represents the first population-level genomic research documenting the invasion dynamics of the successful worldwide invader, H. radicata, outside of Europe.

Bilateral stringhalt associated with Hypochaeris radicata in Uruguayan horses

We reported thirteen cases of bilateral stringhalt associated with Hypochaeris radicata that occurred in horses in Uruguay during a severe drought in the summer of 2023. All horses were affected chronically and progressively by bilateral hyperflexion of hindlimbs. In two severely affected horses, the main histological lesions included neuronal chromatolysis and axonal spheroids in the ventral gray horn in the lumbar and sacral spinal cord and axonal degeneration and digestion chambers in ventral roots fibers and long peripheral nerves. We suggest that in addition to injuries to peripheral nerves, lesions in the spinal cord play an important role in the clinical signs of stringhalt in horses.

Parazytoidy z podrodzin Pimplinae (Hymenoptera, Ichneumonidae)i Aphidiinae (Hymenoptera, Braconidae) występujące w zieleni miejskiej miasta Poznania

The study aimed to determine the species composition and abundance of parasitoids from the subfamilies Pimplinae (Hymenoptera, Ichneumonidae) and Aphidiinae (Hymenoptera, Braconidae) found in various habitats in urban greenery and to demonstrate the rela¬tionship between plant species diversity and the species structure of parasitoid assemblages. It was found that only for the subfamily Aphidiinae was there a significant effect of habitats on the abundance of individual assemblages and the effect of years on the total abundance of assemblages. A positive relationship was observed between vegetation diversity and the abundance and species diversity of parasitoids of the subfamily Aphidiinae, as well as similarity in the qualitative-quantitative structure of Pimplinae assemblages present in a given habitat. Positive effects of trees: Betula pendula, Tilia tomentosa, Salix alba and Salix caprea, shrubs: Berberis julianae, Ber¬beris vulgaris and Spiraea japonica, and herbaceous plants: Elymus repens, Festuca rubra and Hypochoeris radicata on the qualitative¬-quantitative structure of parasitoid assemblages of the subfamily Pimplinae by creating a suitable food base for these entomophagous imagines were noted.

Morphological and Molecular Detection of Spongospora subterranea on Plant Harvest in Infected Powder Scab Plots in Antioquia

Potato powdery scab is a disease that negatively affects both roots, causing gall formation, and tubers, resulting in brown pustules. Additionally, it leads to the development of resistance structures that can persist in the soil for several years. Globally, it is one of the most limiting diseases for potato cultivation. This study aimed to identify the species present in areas with a historical occurrence of powdery scab and to evaluate their role as alternative hosts for the pathogen. Samples were collected in the municipalities of Santa Rosa de Osos and La Unión (Ant- Col). The presence of structures (plasmodia and cystosori) associated with the pathogen in the roots was determined using trypan blue staining followed by optical microscopy analysis. Morphological identification revealed twenty-six families with pathogen structures, including Acmella mutisii, Amaranthus dubius, Bidens pilosa, Galinsoga quadriradiata, Holcus lanatus, Hypochaeris radicata, Juncus microcephalus, Oxalis corniculata, Pennisetum clandestinum, Phytolacca bogotensis, Poa annua, Polygonum nepalense, Raphanus raphanistrum, Rumex crispus, Sonchus oleraceus, Trifolium repens, Verbena litoralis, along with Fragaria x ananassa, Solanum tuberosum, and Zea mays. Molecular analysis using RT-PCR for the detection of Plasmodiophoromycetes revealed the presence of Spongospora subterranea in Solanum tuberosum; Polymyxa betae in S. tuberosum, O. corniculata, and T. repens; and Polymyxa graminis in Z. mays. This comprehensive study highlights the importance of crop rotation and weed control to disrupt the pathogen’s lifecycle as effective strategies to mitigate the impact of the disease. It emphasizes the role of alternative hosts and their substantial contribution to elevated inoculum levels.

SSPs 기후변화 시나리오에 따른 서양금혼초(Hypochaeris radicata)의 개화 생물계절 및 적합 서식지 분포 예측

SSPs 기후변화 시나리오에 따른 서양금혼초(Hypochaeris radicata)의 개화 생물계절 및 적합 서식지 분포 예측

New findings of adventive plants in the Tomsk Region

The article contains new data on localities of new and rare adventive plants in the Tomsk Region. Hypochaeris radicata L. is not only a new species but a representative of a new genus for the flora of Siberia; Geranium pusillum L. is reported here for the first time for the Tomsk Region and constitutes the first record within the forest zone of Siberia; for 4 rare adventive species (Bidens frondosa L., Impatiens parviflora DC., Cynoglossum officinale L., Hesperis pycnotricha Borbás et Degen), new localities were noted, indicating their further distribution in the southern regions of the Tomsk Region and extending the distribution range of the species.

A ballistic pollen dispersal strategy based on stylar oscillation of Hypochaeris radicata (Asteraceae).

Asteraceae, one of the largest flowering plant families, is adapted to a vast range of ecological niches. Their adaptability is partially based on their strong ability to reproduce. The initial, yet challenging, step for the reproduction of animal-pollinated plants is to transport pollen to flower-visiting pollinators. We adopted Hypochaeris radicata as a model species to investigate the functional morphology of the typical floral feature of Asteraceae, a pollen-bearing style. Using quantitative experiments and numerical simulations, here we show that the pollen-bearing style can serve as a ballistic lever for catapulting pollen grains to pollinators. This can potentially be a pollen dispersal strategy to propel pollen to safe sites of pollinators' bodies, which are beyond the physical reach of the styles. Our results suggest that the specific morphology of the floret and the pollen adhesion avoid pollen waste by catapulting pollen within a specific range equal to the size of a flowerhead. The insights into the functional floral oscillation may shed light on the superficially unremarkable, but ubiquitous functional floral design of Asteraceae.

Effects of land-use types and the exotic species, Hypochaeris radicata, on plant diversity in human-transformed landscapes of the biosphere reserve, Jeju Island, Korea

Land-use and plant invasion influence biodiversity. Understanding the effects of land-use types and invasive plants on the ecosystem is crucial for better management and the development of strategic plans for increasing biodiversity in Jeju Island, Korea, a designated Biosphere Reserve by the United Nations Education, Scientific, and Cultural Organization. The effect of the most dominant invasive exotic species, Hypochaeris radicata, on the four land-use types of Jeju Island was investigated. Plant composition, soil characteristics, and plant diversity among four land-use types (cropland, green space, neglected land, and residential) were compared. Among the land-use types, croplands had the most diverse plant composition and the highest richness in exotic and native plant species. Croplands, such as tangerine orchards, which are widely distributed throughout Jeju Island, showed the highest plant diversity because of medium intensity disturbance caused by weed removal. The relative cover of H. radicata did not differ between land-use types. However, H. radicata invasion was negatively related with plant species richness, making this invasive species a threat to the biodiversity of native herbs present in land-use areas. H. radicata adapts to areas with a broad range of soil properties and a variety of land-use types. Therefore, it is crucial to monitor land-use types and patterns of plant invasion to guide the implementation of consistent management and conservation strategies for maintaining ecosystem integrity of the transformed habitat in Jeju Island.

The diversity of iron acquisition strategies of calcifuge plant species from dry acidic grasslands

Although the calcifuge plant species existing in dry acidic grasslands are believed to be prone to iron (Fe)-dependent limitations, little is known about their susceptibility and reaction to pH-dependent Fe starvation. Therefore, the present study examines the effects of contrasting soils (acidic Podzol vs alkaline Rendzina) and Fe supplementation (Fe-HBED) on alkaline substratum (5 and 25 μmol Fe-HBED kg−1 soil). Five calcifuge dicotyledonous plant species (Alyssum montanum L., Antennaria dioica (L.) Gaertn., Hypochaeris radicata L., Jasione montana L. and Potentilla arenaria Borkh.) were tested in a pot experiment under field conditions. Chlorosis, chlorophyll content, growth and chlorophyll a fluorescence were measured. The elemental composition (contents of Ca, Mg, Fe, Mn, Zn and Cu) of the roots and shoots were analyzed, as well as their specialized metabolites. Two studied species (A. dioica d and J. montana) were susceptible to pH-dependent chlorosis, and this deficiency was successfully diminished by the application of Fe-HBED. Almost all the studied species (except A. montanum) preferred the acidic soil. Fe-HBED treatments were not sufficient for supporting the growth of H. radicata and J. montana in alkaline soil to the same degree as in acidic soil, which suggests additional non-Fe-dependent limitations. Both Fe starvation and Fe over-supplementation caused species-specific changes in chlorophyll a fluorescence. The disturbed Fe acquisition in the alkaline soil was not the sole source of the observed limitations, as the chlorosis-susceptible species demonstrated a complex interaction between Fe, Mn and Zn. The species resistant to lime chlorosis contained greater amounts of specialized metabolites than the susceptible plants. Our findings do not support hypothesis that all calcifuges are susceptible to Fe-dependent chlorosis: calcifuge plant species from dry acidic grasslands appear to have diverse Fe requirements and acquisition strategies.

Quantifying the Influence of Pollen Aging on the Adhesive Properties of Hypochaeris radicata Pollen.

Simple SummaryPollination is the transfer of pollen from a plant’s male part (anther) to the corresponding female part (stigma). It is a fundamental biological process that ensures plant reproduction. Most studies investigate pollination from a biological perspective, but the underlying physical processes are poorly understood. Many plants rely on insects to transport pollen and the forces with which pollen adhere to insects and floral surfaces are fundamental for successful pollination. We quantified pollen adhesion by measuring the forces necessary to detach Hypochaeris radicata (catsear, a common insect-pollinated plant) pollen from glass and studied for the first time how the adhesion forces change with pollen aging. Our results show that newly formed adhesion bonds between H. radicata pollen and glass are stronger for fresh pollen than for old ones. On the other hand, when H. radicata pollen age in contact with glass, the adhesion between pollen and glass strengthens over time. These effects are probably caused by the viscous liquid covering most pollen (pollenkitt) changing its viscoelastic properties as it dries.Although pollination is one of the most crucial biological processes that ensures plant reproduction, its mechanisms are poorly understood. Especially in insect-mediated pollination, a pollen undergoes several attachment and detachment cycles when being transferred from anther to insect and from insect to stigma. The influence of the properties of pollen, insect and floral surfaces on the adhesion forces that mediate pollen transfer have been poorly studied. Here, we investigate the adhesive properties of Hypochaeris radicata pollen and their dependence on pollen aging by quantifying the pull-off forces from glass slides using centrifugation and atomic force microscopy. We found that the properties of the pollenkitt—the viscous, lipid liquid on the surface of most pollen grains—influences the forces necessary to detach a pollen from hydrophilic surfaces. Our results show that aged H. radicata pollen form weaker adhesions to hydrophilic glass than fresh ones. On the other hand, when a pollen grain ages in contact with glass, the adhesion between the two surfaces increases over time. This study shows for the first time the pollen aging effect on the pollination mechanism.

Spatial heterogeneity of environmental factors related to the invasion of Hypochaeris radicata in South Korea

Early detection of the spatial expansion pattern of alien plants and the associated environmental factors are essential for their management. In this study, we applied regression kriging and geographically weighted regression, which can incorporate spatial autocorrelation into the model, to estimate the critical environmental factors related to the invasion of Hypochaeris radicata into new habitats. We spatially interpolated the occurrence probabilities of H. radicata based on field survey data from 2000–2001 and 2018–2020 to compare the distribution pattern of this species over 20 years. Further, we evaluated the relative importance of environmental variables for the invasion of H. radicata using geographically weighted regression. Based on the results of our model, the expansion of H. radicata was found to be significantly associated with anthropogenic activities, such as human footprinting (HFP) and residential area, and the transportation system area. These results suggest that the primary dispersal forces of H. radicata are human activities, and that roads may be the main corridor of its expansion. Additionally, H. radicata did not invade the forest area over the 20 years. We can predict that this plant may flourish better around big cities because of human activities. Furthermore, deforestation and sporadic mowing can accelerate the expansion of H. radicata because of its preference for sunny spots.

First contribution to the ethnobotanical knowledge in the Peloritani Mounts (NE Sicily)

This paper presents the results of an ethnobotanical survey carried out in the Peloritani Mounts (NE Sicily). This investigation aims to illustrate the first record known of the traditional uses of plants in this territory through the case study of a small rural suburb named Tipoldo (Messina). The data were collected from 20 informants over the age of 66, who were mainly farmers and shepherds, and were analyzed using two quantitative ethnobotanical indicators. For each plant was reported the Latin name, life form, vernacular name, parts used, ethnobotany category, claimed uses, status, and their relative indexes. Based on semi-structured interviews carried out between February 2017 and May 2018, a listing was compiled of 126 wild plants belonging to 51 families, the most predominant being Asteraceae (19 species) and Fabaceae (15 species). The most common ethnobotanical uses reported are medicinal (30%) and agropastoral use (19%). Among the preparation methods indicated, leaves (39%) were the most commonly used parts of the plants, while the species most mentioned in connection with ethnobotanical applied indexes were: Crepis vesicaria, Dittrichia graveolens, Hypochaeris radicata, Salvia Rosmarinus and Clinopodium nepeta. These practices are presently performed only by a few elderly people, who rely on plants solely for a few activities. Furthermore, ethnobotanical studies are fundamental to clear up the knowledge on the traditional plant uses that are still current in this part of Sicily, to preserve this cultural heritage for future generations.

The complete chloroplast genome of Crepis rigescens (Cichorioideae), a traditional Chinese medicinal plant

Crepis rigescens, Diels 1921 is a traditional Chinese medicinal plant of Cichorioideae, which contains many chemicals, such as friedelin, β-sitosterol, stigmasterol, chlorogenic acid, and flavonoids, and so on, which has the characteristics of high medicinal value and small side effect. Crepis rigescens was used as folk medicines for anti-bacterial, and anti-oxidation, which also had a potential curative effect in preventing cardiovascular disease and anti-tumor. Illumina paired-end reads data were used to assemble the complete chloroplast (cp) genome. 14,425,796 raw paired-end reads and the length distribution in 124,685 bp, including a large single copy (LSC) region of 82,924 bp, a small single copy (SSC) region of 18,150 bp, and a pair of inverted repeat (IRs) regions of 25,128 bp. Besides, 10 protein-coding genes (PCGs) genes and 6 tRNAs genes possess a single intron, while clpP and ycf3 have a couple of introns. Based on the concatenated coding sequences of cp PCGs, the phylogenetic analysis showed that C. rigescens and Hypochaeris radicata (MH746729) are closely related to each other within the family Cichorioideae.

A field experiment characterizing variable detection rates during plant surveys.

Surveys aimed at finding threatened and invasive species can be challenging due to individual rarity and low and variable individual detection rates. Detection rate in plant surveys typically varies due to differences among observers, among the individual plants being surveyed (targets), and across background environments. Interactions among these 3 components may occur but are rarely estimated due to limited replication and control during data collection. We conducted an experiment to investigate sources of variation in detection of 2 Pilosella species that are invasive and sparsely distributed in the Alpine National Park, Australia. These species are superficially similar in appearance to other yellow‐flowered plants occurring in this landscape. We controlled the presence and color of flowers on target Pilosella plants and controlled their placement in plots, which were selected for their variation in cover of non‐target yellow flowers and dominant vegetation type. Observers mimicked Pilosella surveys in the plots and reported 1 categorical and 4 quantitative indicators of their survey experience level. We applied survival analysis to detection data to model the influence of both controlled and uncontrolled variables on detection rate. Orange‐ and yellow‐flowering Pilosella in grass‐ and heath‐dominated vegetation were detected at a higher rate than nonflowering Pilosella. However, this detection gain diminished as the cover of other co‐occurring yellow‐flowering species increased. Recent experience with Pilosella surveys improved detection rate. Detection experiments are a direct and accessible means of understanding detection processes and interpreting survey data for threatened and invasive species. Our detection findings have been used for survey planning and can inform progress toward eradication. Interaction of target and background characteristics determined detection rate, which enhanced predictions in the Pilosella eradication program and demonstrated the difficulty of transferring detection findings into untested environments.

Seed dispersal by wind decreases when plants are water-stressed, potentially counteracting species coexistence and niche evolution.

Hydrology is a major environmental factor determining plant fitness, and hydrological niche segregation (HNS) has been widely used to explain species coexistence. Nevertheless, the distribution of plant species along hydrological gradients does not only depend on their hydrological niches but also depend on their seed dispersal, with dispersal either weakening or reinforcing the effects of HNS on coexistence. However, it is poorly understood how seed dispersal responds to hydrological conditions. To close this gap, we conducted a common‐garden experiment exposing five wind‐dispersed plant species (Bellis perennis, Chenopodium album, Crepis sancta, Hypochaeris glabra, and Hypochaeris radicata) to different hydrological conditions. We quantified the effects of hydrological conditions on seed production and dispersal traits, and simulated seed dispersal distances with a mechanistic dispersal model. We found species‐specific responses of seed production, seed dispersal traits, and predicted dispersal distances to hydrological conditions. Despite these species‐specific responses, there was a general positive relationship between seed production and dispersal distance: Plants growing in favorable hydrological conditions not only produce more seeds but also disperse them over longer distances. This arises mostly because plants growing in favorable environments grow taller and thus disperse their seeds over longer distances. We postulate that the positive relationship between seed production and dispersal may reduce the concentration of each species to the environments favorable for it, thus counteracting species coexistence. Moreover, the resulting asymmetrical gene flow from favorable to stressful habitats may slow down the microevolution of hydrological niches, causing evolutionary niche conservatism. Accounting for context‐dependent seed dispersal should thus improve ecological and evolutionary models for the spatial dynamics of plant populations and communities.

계층분석방법(AHP)과 전문가 설문조사를 활용한 농업생태계 기후변화 지표생물 30종 선정

It is more efficient to select and monitor a few climate-sensitive organisms to assess the impacts of climate change on agroecosystems. In this study, indicator species of climate change in agroecosystem in South Korea were selected through analytical hierarchy process and an expert questionnaire survey. Climate sensitivity, agroecosystem symbolism, survey easiness, identification easiness, and public interest were selected as criteria for indicator species, with weights of 0.38 (±0.15), 0.23 (±0.13), 0.18 (±0.11), 0.14 (±0.09), and 0.07 (±0.06), respectively. According to these criteria, 30 indicator species were finally selected from six taxonomic groups of plants, aquatic invertebrates, bees, terrestrial beetles, butterflies, and spiders as follows. Seven plant species were selected: Taraxacum officinale, Capsella bursa-pastoris, Veronica persica, Hypochaeris radicata, Lamium amplexicaule, Trigonotis peduncularis, and Conyza sumatrensis. Seven aquatic invertebrate species were selected: Pomacea canaliculata, Cybister chinensis, Hydrochara affinis, Sternolophus rufipes, Hydaticus grammicus, Appasus japonicus, and Rhantus suturalis. Five butterfly species were selected: Eurema mandarina, Chilo suppressalis, Pieris rapae, Papilio xuthus, and Colias erate. Three spider species were selected: Argiope bruennichi, Larinioides cornutus, and Neoscona adianta. Four bee species were selected: Vespa velutha nigrithorax, V. simillima simillima, V. mandarinia, and V. simillima xanthoptera. Four species were selected for terrestrial beetles: Pheropsophus javanus, P. jessoensis, Platydracus brevicornis, and Chlaenius micans. The selected species are expected to be used as indicators for assessing the impacts of climate change in agroecosystems in the future.

Soil nitrogen availability favours the growth but not germination of secondary invaders after clearing invasive Acacia saligna

Invasive alien nitrogen-fixing species, such as Australian acacias, often leave a legacy of elevated available soil nitrogen after their removal. This legacy effect can facilitate secondary invasion by other alien species, thereby preventing natural restoration of areas being managed. To restore viable native plant communities in ecosystems where secondary invasion is a barrier to restoration, it is important to understand the soil legacy effects of invasions. Using Acacia saligna (Labill.) H. L. Wendl. (Fabaceae) invasions in the South African fynbos as case study, we determined (1) the extent to which levels of available soil nitrogen influence the germination and growth of secondary invaders; and (2) how this differs between secondary invader species. We chose five of the most common species that have been identified as secondary invaders after clearing invasive A. saligna in the Cape Flats Sand Fynbos: (i) Avena fatua (L.) (Poaceae), (ii) Briza maxima (L.) (Poaceae), (iii) Bromus diandrus (Roth.) (Poaceae), (iv) Hypochaeris radicata (L.) (Asteraceae), and (v) Raphanus raphanistrum (L.) (Brassicaceae). Using proportional fertigation, we created soil nitrate levels similar to those found in non-invaded areas (1mg/kg), and the lowest (3 mg/kg), median (7.5 mg/kg) and highest (12 mg/kg) levels typically found in areas previously invaded by A. saligna up to ten years after clearing. For each soil nitrate level, we germinated secondary invader seeds (five seeds per petri dish) in an incubator (five species × four soil nitrate levels × five replicates = 100 petri dishes). Furthermore, for each soil nitrate level, we grew secondary invaders (one plant per pot) in a greenhouse tunnel for five months (five species × four soil nitrate levels × five replicates = 100 pots). There was no significant relationship between germination success and soil nitrate level for any species. However, root and shoot dry mass were significantly positively correlated to soil nitrate level for all species. The relationship was nonetheless only linear for Bromus diandrus, Hypochaeris radicata, and Raphanus raphanistrum. These results indicate that the legacy of elevated available soil nitrogen does not have an effect on the germination of secondary invaders, but favours their growth. Therefore, secondary invasion can be managed through a reduction in soil nitrogen levels. However, secondary invader growth does not decrease at the same rate for all species in response to a decrease in available soil nitrogen. Thus, the use of soil nitrogen reduction as a tool for the management of secondary invasions should take into account the species being managed. However, given that multiple secondary invader species often dominate a restoration site, restoration efforts should reduce soil nitrogen to non-invaded levels to account for the different response rates to available soil nitrogen, and simply management efforts.

Homeowner preferences drive lawn care practices and species diversity patterns in new lawn floras

Abstract Households intensively manage lawns to create uniformly green, low diversity plant communities. Because lawns occupy a large proportion of urban green space, they are a crucial case for understanding how people manipulate urban vegetation. In this study, I focused on 58 homeowners who purchased a newly constructed home and yard in the Seattle Metropolitan Statistical Area, USA, to see how preferences, lawn care regimes and new lawn floras develop within a multi-scalar urban environment. A typical homeowner watered 3 times in spring, watered 24 times in summer, applied fertilizer twice, mowed 21 times and edged 15 times. Most new lawn turfgrasses were Lolium perenne, Poa pratensis and/or Festuca spp. Mean species richness was 6.5 ± 5.3 species. The most frequent species were non-native and cosmopolitan (turfgrasses, Hypochaeris radicata, Taraxacum officinale and Trifolium repens). Five variables increased the probability of homeowners managing their lawns as turfgrass monocultures: living in a neighborhood with larger yards, summer watering frequency, fertilizer frequency, valuing space for children and valuing wildlife habitat. Valuing an easy to manage yard decreased the turfgrass monoculture probability. In polyculture yards, having a larger lawn was positively correlated with non-turfgrass species richness, but elevation was negatively correlated. Homeowners who valued space for children appeared to have more intensive lawn care regimes than those who valued wildlife habitat or easy to manage yards. Although lawn floras result from complex interactions of the environment and households, urban characteristics appeared to be weaker drivers of diversity than homeowner preferences and lawn care.

Nitrogen signals and their ecological significance for seed germination of ten psammophilous plant species from European dry acidic grasslands.

The presented study evaluated effects of potassium nitrate (KNO3), ammonium nitrate (NH4 NO3) and ammonium chloride (NH4Cl) on the germination-related characteristics of 10 species from European dry acidic grasslands. Germination was studied under controlled laboratory conditions. The seeds were subjected to KNO3, NH4 NO3 and NH4Cl in four doses (1, 10, 50 and 100 mM) and to distilled water. Final germination percentage, index of germination velocity and index of germination synchrony were determined. Content of nitrogen in the soil probed from the site of seeds collection was also analyzed. Significant effects of type of the nitrogen compounds and their concentrations were observed. High concentrations of nitrogen-containing salts inhibited completion of germination in almost all species. Helichrysum arenarium and Hypericum perforatum showed preference for NH4+ over NO3‒, whereas Arnoseris minima, Alyssum montanum, Jasione montana and Spergula morisonii showed preference for NO3‒ over NH4+. Centaurea scabiosa, C. stoebe and Hypochaeris radicata had no preference and wide tolerance to the type of nitrogen-containing compound. Echium vulgare showed differential response hard for interpretation. A. montanum and J. montana showed stenotopic behavior in terms of nitrogen-related conditions. It is proposed that nitrogen-rich soil gaps favor establishment of more nitro-tolerant plant species (e.g. C. scabiosa, C. stoebe and H. radicata) as compared to nitrogen-poor ones.

Field study on Hypochaeris radicata L. in horse pastures in Germany – Australian stringhalt as a climatic and ecological phenomenon

Field study on Hypochaeris radicata L. in horse pastures in Germany – Australian stringhalt as a climatic and ecological phenomenon