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Wild plant populations may harbour a myriad of unknown viruses. As the majority of research efforts have targeted economically important plant species, the diversity and prevalence of viruses in the wild has remained largely unknown. However, the recent shift towards metagenomics-based sequencing methodologies, especially those targeting small RNAs, is finally enabling virus discovery from wild hosts. Understanding this diversity of potentially pathogenic microbes in the wild can offer insights into the components of natural biodiversity that promotes long-term coexistence between hosts and parasites in nature, and help predict when and where risks of disease emergence are highest. Here, we used small RNA deep sequencing to identify viruses in Plantago lanceolata populations, and to understand the variation in their prevalence and distribution across the Åland Islands, South-West Finland. By subsequent design of PCR primers, we screened the five most common viruses from two sets of P. lanceolata plants: 164 plants collected from 12 populations irrespective of symptoms, and 90 plants collected from five populations showing conspicuous viral symptoms. In addition to the previously reported species Plantago lanceolata latent virus (PlLV), we found four potentially novel virus species belonging to Caulimovirus, Betapartitivirus, Enamovirus, and Closterovirus genera. Our results show that virus prevalence and diversity varied among the sampled host populations. In six of the virus infected populations only a single virus species was detected, while five of the populations supported between two to five of the studied virus species. In 20% of the infected plants, viruses occurred as coinfections. When the relationship between conspicuous viral symptoms and virus infection was investigated, we found that plants showing symptoms were usually infected (84%), but virus infections were also detected from asymptomatic plants (44%). Jointly, these results reveal a diverse virus community with newly developed tools and protocols that offer exciting opportunities for future studies on the eco-evolutionary dynamics of viruses infecting plants in the wild.

Plantago lanceolata L., folium (ribwort plantain) is an active pharmaceutical ingredient in traditional herbal medicinal products (THMP) available in pharmacies as a demulcent for the symptomatic treatment of oral or pharyngeal irritations and associated dry cough. This kind of THMP is widely applied among the European population; however, recently, voices have been heard in the public about alleged cadmium impurities. The idea of our study was a comprehensive risk assessment of the Cd impurity exposure and its effect on human health. Our assessment strategy was based on regulatory aspects (raw results versus limits set by FAO/WHO for herbal medicines) and toxicological risk assessment approach based on ICH Q3D guideline for elemental impurities in final pharmaceutical products. The cadmium was determined by electrothermal atomization atomic absorption spectrometry based on our previously described methodology. Obtained results show that all analysed THMP with P. lanceolata L., folium available in the Polish pharmacies contain cadmium impurities, but at a very low level (ranged 0.73 – 20.6 μg/L). The content of Cd in a single dose (ng/single dose) is also very low and is not a threat to patients. The estimated maximum daily exposure (ng/day) of Cd based on the ‘worst-case scenario’ (maximum concentrations by oral administration) meets the standards of ICH Q3D guideline (all results were below oral permitted daily exposure; PDE for Cd, i.e. < 5.0 µg/day). It can be concluded that all analysed samples of THMP with P. lanceolata L., folium should not represent any health hazard to the patients due to cadmium levels. To the best of our knowledge, this is the first study about Cd impurity level in THMP with P. lanceolata L., folium (ribwort plantain leaves) available in European pharmacies.

Aims Phosphorus (P) limits crop yield and P-fertilisers are frequently applied to agricultural soils. However, supplies of quality rock phosphate are diminishing. Plants have evolved mechanisms to improve Pacquisition and understanding these could improve the long-term sustainability of agriculture. Here we examined interactions between root hairs and arbuscular mycorrhizal (AM) colonisation in barley (Hordeum vulgare L.). Methods Barley mutants exhibiting different root hair phenotypes, wild type barley and narrowleaf plantain (Plantago lanceolata L.) were grown in the glasshouse in P-sufficient and P-deflcient treatments and allowed to develop AM colonization from the natural soil community. Plants were harvested after 6 weeks growth and root hair length, AM-fungal colonisation, shoot biomass and P-accumulation measured. Results Under P-deflcient conditions, root hair length and AM colonisation were negatively related suggesting that resources are allocated to root hairs rather than to AM fungi in response to P-deficiency. There was evidence that barley and narrowleaf plantain employed different strategies to increase P-acquisition under identical conditions, but root hairs were more effective. Conclusions This research suggests future barley breeding programmes should focus on maintaining or improving root hair phenotypes and that pursuing enhancements to AM associations under the prevalent agricultural conditions tested here would be ineffectual.

Buckhorn plantain populations purportedly resistant to 2,4-D were identified in Pennsylvania following long-term, continual applications of the active ingredient to turfgrass. The research objectives of this study were to 1) confirm 2,4-D resistance with dose-response experiments, 2) confirm field resistance of buckhorn plantain to 2,4-D in Pennsylvania, and 3) evaluate alternative herbicides for 2,4-D-resistant buckhorn plantain. Greenhouse dose-response experiments evaluated the sensitivity of buckhorn plantain biotypes that were resistant or susceptible to 2,4-D, and to halauxifen-methyl, two synthetic auxin herbicides from different chemical families. The resistant biotype was ≥11.3 times less sensitive to 2,4-D than the susceptible biotype and required a 2,4-D dosage ≥4.2 times greater than the standard application rate to reach 50% necrosis. No cross-resistance was observed to halauxifen-methyl because both resistant and susceptible populations demonstrated similar herbicide sensitivity. Field experiments confirmed previous reports of ineffectiveness (≤30% reduction) with 2,4-D and other phenoxycarboxylic herbicides in potentially resistant buckhorn plantain biotypes. Treatments containing halauxifen-methyl resulted in a ≥70% reduction in resistant biotypes. This is the first known report of synthetic auxin herbicide resistance in any weed species in Pennsylvania and highlights emerging herbicide resistance challenges in turfgrass systems. Nomenclature: 2, 4-D; halauxifen-methyl; buckhorn plantain, Plantago lanceolata L. PLALA

Extensive traditional use of medical plants leads to research dealing with chemical composition of essential oils. The aim of this work was evaluation of quality of the essential oil and extending of the knowledge about chemical composition of essential oil from ribwort ( Plantago lanceolata L.) and proportional representation of compounds. Extractions of essential oils from samples of ribwort were performed by hydrodistillation. GC-MS and GC-FID techniques were used for investigation of the qualitative and semi-quantitative content of aromatic compounds in the essential oils, respectively. Major aroma constituents of ribwort leaves were groups of fatty acids 28.0–52.1 % (the most abundant palmitic acid 15.3–32.0 %), oxidated monoterpenes 4.3–13.2 % (linalool 2.7–3.5 %), aldehydes and ketones 6.9–10.0 % (pentyl vinyl ketone 2.0–3.4 %) and alcohols 3.8–9.2 % (1-octen-3-ol 2.4–8.2 %). In relative high amount were identified apocarotenoids (1.5–2.3 %) which are important constituents because of their intense fragrant. The importance is in potential manufacture control of feedstocks before producing of food supplements.

We investigated how shoot and root allocation in plants responds to increasing levels of competitive stress at different levels of soil fertility. In addition, we analyzed whether different responses were due to adaptive plasticity or should be attributed to ontogenetic drift. Plantago lanceolata plants were grown during 18 weeks at five plant densities and four nutrient supply levels in pots in the greenhouse. Thereafter root and shoot biomass was measured. There were clear negative effects of increasing plant densities on plant weights revealing strong intraspecific competition. At the lower N-treatments, the proportional allocation to root mass increased with increasing competitive stress, indicating the important role of belowground competition. At the higher N-supply rate, the relationship between competitive stress and shoot to root ratio was neutral. These responses could not be attributed to ontogenetic drift, but could only be explained by assuming adaptive plasticity. It was concluded that at lower N-supplies belowground competition dominates and leads to increased allocation to roots, while at the higher N-supply competition for soil resources and light had balanced impacts on shoot and root allocation. An alternative hypothesis explaining the observed pattern is that light competition has far less pronounced impacts on root-shoot allocation than nutrient deprival.

Deciphering the mechanisms that drive variation in biomass production across plant communities of contrasting species composition and diversity is a main challenge of biodiversity–ecosystem functioning research. Niche complementarity and selection effect have been widely investigated to address biodiversity–productivity relationships. However, the overlooking of the specific role played by key species has limited so far our capacity to comprehensively assess the relative importance of other potential drivers of biodiversity effects. Here, we conducted a grassland diversity–productivity experiment to test how four potential facets of biodiversity effects, namely species richness, functional diversity, species identity and the relaxation of intraspecific competition, account for variations in above and root biomass production. We grew six plant species in monoculture, as well as in every combination of two, three and six species. Plant density was kept constant across the richness gradient but we additionally grew each species in half‐density monoculture to estimate the strength of intraspecific competition for each studied species. We characterized eight functional traits, including root traits, related to nutrient and light acquisition and computed both the functional dissimilarity and the community‐weighted mean (CWM) of each trait. We further partitioned above‐ground biodiversity effect into complementarity and selection effects. We observed strong positive biodiversity effects on both above‐ground and root biomass as well as strong positive complementarity effect. These arose largely from the presence of a particular species (Plantago lanceolata) and from CWM trait values more than from a higher functional dissimilarity in plant mixtures. P. lanceolata displayed the highest intraspecific competition, which was strongly relaxed in species mixtures. By contrast, the presence of Sanguisorba minor negatively affected the productivity of plant mixtures, this species suffering more from interspecific than intraspecific competition. This study provides strong evidences that the search for key species is critical to understand the role of species diversity on ecosystem functioning and demonstrates the major role that the balance between intraspecific and interspecific competition plays in biodiversity–ecosystem functioning relationships. Developing more integrative approaches in community and ecosystem ecology can offer opportunities to better understand the role that species diversity plays on ecosystem functioning. A free Plain Language Summary can be found within the Supporting Information of this article. A free Plain Language Summary can be found within the Supporting Information of this article.

Biodiversity, a multidimensional property of natural systems, is difficult to quantify partly because of the multitude of indices proposed for this purpose. Indices aim to describe general properties of communities that allow us to compare different regions, taxa, and trophic levels. Therefore, they are of fundamental importance for environmental monitoring and conservation, although there is no consensus about which indices are more appropriate and informative. We tested several common diversity indices in a range of simple to complex statistical analyses in order to determine whether some were better suited for certain analyses than others. We used data collected around the focal plant Plantago lanceolata on 60 temperate grassland plots embedded in an agricultural landscape to explore relationships between the common diversity indices of species richness (S), Shannon's diversity (H'), Simpson's diversity (D1), Simpson's dominance (D2), Simpson's evenness (E), and Berger–Parker dominance (BP). We calculated each of these indices for herbaceous plants, arbuscular mycorrhizal fungi, aboveground arthropods, belowground insect larvae, and P. lanceolata molecular and chemical diversity. Including these trait‐based measures of diversity allowed us to test whether or not they behaved similarly to the better studied species diversity. We used path analysis to determine whether compound indices detected more relationships between diversities of different organisms and traits than more basic indices. In the path models, more paths were significant when using H', even though all models except that with E were equally reliable. This demonstrates that while common diversity indices may appear interchangeable in simple analyses, when considering complex interactions, the choice of index can profoundly alter the interpretation of results. Data mining in order to identify the index producing the most significant results should be avoided, but simultaneously considering analyses using multiple indices can provide greater insight into the interactions in a system. Biodiversity is a difficult concept to quantify, partly because of its multidimensional nature, and many simple to complex indices have been developed for this purpose. We collected data on diversity of herbaceous plants, arbuscular mycorrhizal fungi, aboveground arthropods, belowground insect larvae, and Plantago lanceolata molecular and chemical diversity in 60 temperate grasslands and calculated a variety of simple to complex diversity indices for each (S, H', D1, D2, E, BP). While these common diversity indices appeared interchangeable in simple analyses quantifying changes in diversity, when quantifying interactions between diversities the conclusions varied with the index chosen.

Future climate scenarios predict increases in elevated atmospheric CO sub(2), air temperature and drought, but the impacts of multiple climate change factors on ecosystem functioning remain unclear. In this study, we compared drought responses of plants under future versus current climate conditions. In addition to focusing on stress during the drought itself, we also examined post-drought lagged effects, and whether warming and elevated CO sub(2) alter these. We grew monocultures and mixtures of two grassland species (Lolium perenne L. and Plantago lanceolata L.) in four simulated climate scenarios: (1) current climate, (2) current climate with drought, (3) warmer temperature with drought and (4) combined warming, elevated CO sub(2) and drought. L. perenne and P. lanceolata were influenced by the climate scenario but not differently enough to modify the competitive balance. Warming aggravated drought impacts on L. perenne and elevated CO sub(2) only partly compensated for these effects. In a warmer climate, with or without elevated CO sub(2), drought continued to enhance senescence and mortality in L. perenne long after the water shortage, while such lag effects were not observed in current climate. In P. lanceolata, a similar stimulation of senescence and mortality was induced, but only under combined warming and elevated CO sub(2). These lag effects induced by the future climate may reduce resilience.

The ecological consequences of future droughts are difficult to predict due to a limited understanding of the nonlinear responses of plants to increasing drought intensity, which can change abruptly when critical thresholds of drought intensity are crossed. Drought responses are composed of resistance and postdrought recovery. Although it is well established that higher drought intensity increases the impact and, thus, reduces plant resistance, less is known about how drought intensity affects recovery and how resistance and recovery are related. In this study, we tested the hypothesis that resistance, recovery, and their relationship change abruptly upon crossing critical thresholds of drought intensity. We exposed mesocosms of two monospecific stands of the common grassland species Dactylis glomerata and Plantago lanceolata to a large gradient of drought intensity and quantified the resistance and recovery of multiple measures of plant productivity, including gross-primary productivity, vegetative height, Normalized Difference Vegetation Index, and aboveground biomass production. Drought intensity had nonlinear and contrasting effects on plant productivity during drought and recovery, which differed between the two species. Increasing drought intensity decreased the resistance of plant productivity and caused rapid compensatory growth during postdrought recovery, the degree of which was highly dependent on drought intensity. Across multiple response parameters two thresholds of drought intensity emerged, upon which we observed abrupt changes in plant resistance and recovery, as well as their relationship. We conclude that across gradients of drought intensity resistance and recovery are tightly coupled and that both the magnitude and the direction of drought effects on resistance and recovery can change abruptly upon specific thresholds of stress intensity. These findings highlight the urgent need to account for nonlinear responses of resistance and recovery to drought intensity as critical drivers of productivity in a changing climate.