Iris Pseudacorus Research Articles

Records of Iris pseudacorus in Argentina according different data-surces

Records of Iris pseudacorus in Argentina according different data-surces

Comprehensive study on removal of bisphenol-S and its metabolic fate using aquatic macrophytes

Bisphenol-S (BPS) is recognized as an emerging contaminant due to its potential estrogenic properties and is frequently detected in aquatic environment. The safety and environmental behavior of BPS is controversial. Furthermore, the removal studies of BPS from aqueous environment are scarce. In this study, we assessed the phytoremediation potential of three aquatic macrophytes (Iris pseudacorus, Ipomoea aquatica, and Typha angustifolia) for BPS removal from secondary wastewater effluent. BPS at environmentally relevant concentration (0.005 mg/L) was removed 100 %, 97 % and 97.5 % with I. pseudacorus, I. aquatica and T. angustifolia respectively. Twelve biotransformed products of BPS were identified through gas chromatography mass spectrophotometry. The enzymatic analysis showed induction of both phase I (laccase, 315 %; peroxidase, 739 %, superoxide dismutase, 881 %; aminopyrine N demethylase, 60 %) and phase II enzymes (glutathione S-transferase, 592 %) in the plant roots after 7 days of BPS exposure. A lab-scale vertical phytoreactor was constructed with PVC tubes that completely removed BPS in 14 days along with nutrients (phosphorus and nitrogen) and inorganic (heavy metals) contaminants from the secondary wastewater effluent. An analysis of the microbial diversity in the phytoreactor effluent showed an enhanced relative abundance of the phyla Bacteroidetes (20 %) and Proteobacteria (44 %) after BPS exposure. This study is the first report highlighting the removal of BPS by aquatic macrophyte and its fate in aquatic environments.

MEDICINAL PLANTS OF THE AQUATIC FLORA OF THE POLTAVA CITY AND SURROUNDING AREA

The article is devoted to the generalization of literary data on the medicinal properties of plants of aquatic flora of the territory of the Poltava city and its surroundings, studied in the course of original research. From the compiled floristic list, a spectrum of medicinal plants was selected, their degree of introduction into medical practice, belonging to protected lists, frequency of occurrence in the study area was analyzed. It was established that 45 (78%) of the 58 species of vascular plants have medicinal properties, including 4 species are officinal, 18 species are folk medicine plants, 23 species are promising for use in pharmacy. For each species, an annotation of its medicinal properties is compiled, which indicates the type of medicinal raw materials and medicinal forms, chemical composition, directions and mechanisms of physiological action on the human body, indications for the use of medicinal preparations.
 It was found that, despite the high participation of medicinal plants in the aquatic flora of the Poltava city and its surroundings, their harvesting in the research area is not appropriate for various reasons: official species (Acorus calamus, Iris pseudacorus, Nuphar lutea, Nymphaea alba) – because of their limited distribution, belonging to various protection lists, and as for mass anthropotolerant species, promising for use in pharmacy (in particular, Ceratophyllum demersum, Lemna minor, Phragmites australis, Typha angustifolia, T. latifolia), their use is limited due to the ability to accumulate harmful substances from polluted ecotopes in urban territory.
 The compromise solutions for harvesting valuable species of medicinal plants that have a limited distribution in nature or grow in polluted ecotopes can be introduction (artificial cultivation of plants ex situ) and biotechnology (cultivation of cells, tissues and organs isolated from the plant on artificial nutrient media in vitro, which allow obtaining a specific target product).

Pesticide sorption and mitigation efficiency of a detention pond in a Champagne vineyard catchment

Detention ponds (DPs) are used to reduce the pesticide inputs from runoff to surface water. This study aimed to assess the role of the sorption process in the mitigation of a DP made up of four successive units and built at the outlet of a vineyard catchment in Champagne (France) to treat runoff waters. Sorption kinetics and isotherms were studied for four pesticides with contrasting properties, cyazofamid (CYA), fludioxonil (FLX), fluopicolide (FLP) and oryzalin (ORY), in the presence of copper in sediments and four emergent macrophyte roots and rhizomes sampled in the DP units 2 (photodegradation) and 3 (phytoremediation). The adsorption equilibrium time (from 24 to 96 h) was less than the hydraulic residence times in the two units (6 and 18 days on average) between November 2016 and November 2017. Sorption equilibrium could then be reached in situ in 85 % of cases. The Kd coefficients of the four pesticides were overall greater in plant roots (14–6742 L kg−1) than in sediments (6–163 L kg−1) because of their affinity for organic matter and the molecular and porous structure of the plant matrices. Typha latifolia and Iris pseudacorus exhibited greater Kd coefficients than Mentha aquatica and Phragmites australis, probably due to their greater specific surface area. The pesticide adsorption capacity in sediments and in T. latifolia and I. pseudacorus roots (ORY ≥ FLX > CYA > FLP) was linked to their Kow. The estimated total annual amounts of the four pesticides adsorbed in situ were determined to be 1236 mg for unit 2 and 1570 mg for unit 3. The four plants improved the removal efficiency of the unit 3 by 33%. Thus, the establishment of suitable and effective plants should be promoted to optimize sorption processes and DP efficiency in reducing water pollution.

Plant selection for roadside rain gardens in cold climates using real-scale studies of thirty-one herbaceous perennials

Plant selection for rain gardens along streets and roads in cold climates can be complicated, as the plants are subjected to combined stresses including periodic inundation, de-icing salts, road dust, splashes of water from the road, freezing and thawing of soil, and periods with ice cover during the winter. The purpose of this study was to identify species suited to grow in these conditions and determine their optimal placement within roadside rain gardens. Thirty-one herbaceous perennial species and cultivars were planted in real-scale rain gardens in a street in Drammen (Norway) with supplemental irrigation, and their progress was recorded during the following three growing seasons. The study highlights considerable differences between species’ adaptation to roadside rain gardens in cold climates, especially closest to the road. Some candidate species/cultivars had a high survival rate in all rain garden positions and were developed well. These were: Amsonia tabernaemontana, Baptisia australis, Calamagrostis × acutiflora ‘Overdam’, Hemerocallis ‘Camden Gold Dollar’, Hemerocallis ‘Sovereign’, Hemerocallis lilioasphodelus, Hosta ‘Sum & Substance’, Iris pseudacorus and Liatris spicata ‘Floristan Weiss’. Other species/cultivars appeared to adapt only to certain parts of the rain garden or had medium tolerance. These were: Calamagrostis brachytricha, Carex muskingumensis, Eurybia × herveyi ‘Twilight’, Hakonechloa macra, Hosta ‘Francee’, Hosta ‘Striptease’, Liatris spicata ‘Alba’, Lythrum salicaria ‘Ziegeunerblut’, Molinia caerulea ‘Moorhexe’, Molinia caerulea ‘Overdam’, and Sesleria autumnalis. Species/cultivars that showed high mortality and poor development at all rain garden positions should be avoided in roadside cold climate rain gardens. These include Amsonia orientalis, Aster incisus ‘Madiva’, Astilbe chinensis var. tacquettii ‘Purpurlanze’, Chelone obliqua, Dryopteris filix-mas, Eurybia divaricata, Geranium ‘Rozanne’, Helenium ‘Pumilum Magnificum’, Luzula sylvatica, Polygonatum multiflorum and Veronicastrum virginicum ‘Apollo’. The study also found considerable differences between cultivars within the same species, especially for Hosta cvv. and Liatris spicata. Further investigations are needed to identify the cultivars with the best adaption to roadside rain gardens in cold climates.

Root exudates release from Myriophyllum aquaticum and effects on nitrogen removal by constructed wetlands

The root exudates released from macrophytes are critical for pollutant removal and associated microorganisms, but their role in nitrogen removal remains poorly understood in constructed wetlands (CWs). The release of root exudates by Myriophyllum aquaticum was quantified using a hydroponic experiment, and then four treatments with and without environmentally relevant concentrations of root exudates were conducted to investigate the effect of root exudates on nitrogen removal in CWs. The dissolved organic carbon (DOC) release rate of M. aquaticum was 1.1–2.2 mg g−1 h−1, significantly higher than that of Typha orientalis (0.58–0.78 mg g−1 h−1) and Iris pseudacorus (0.13–0.14 mg g−1 h−1). The DOC release rate of M. aquaticum was affected by the ammonium concentration and harvesting frequency. The removal efficiencies of ammonium and total nitrogen were higher in the CWs with plants than in those without plants, confirming the crucial role of plants in plant-microbe interactions and nitrogen removal in CWs. The CWs showed significantly higher ammonium removal efficiencies under the root exudate treatments (mean 90.4% and 69.3%) than the no-root exudate treatments (87.3% and 62.0%), while total nitrogen presented no significant difference. The phylum-level taxonomic classification of microbial sequences detected in the sediments was slightly different between the root exudate and no-root exudate treatments. The results suggested that the root exudate mass naturally released by plants may be insufficient to change the carbon to nitrogen ratios of wastewater. More gene copies were observed in the rhizosphere sediments than the bulk sediments (p < 0.05), indicating that root exudates had a positive effect on microbes distribution within the rhizosphere. Therefore, high levels of root exudates as external carbon sources should be added to enhance nitrogen removal in CWs for carbon-limited wastewater treatment. The present study provided new insights into the role of macrophytes in pollutant removal and management strategy of CWs for wastewater treatment.

Mixed culture of plants improved nutrient removal in constructed wetlands: response of microbes and root exudates.

Root exudates are determined by plant species configuration and affect microbial community, which in turn affect purification efficiency of constructed wetlands (CWs). However, it is not well understood how plant configuration affects CW purification efficiency through specific root exudates. Herein, four mixed culture CWs were constructed; CW-G3 with Iris pseudacorus, Iris sibirica, Juncus effusus, and Hydrocotyle vulgaris showed the optimal diversity nutrients removal efficiency (TN: 94.2%, TP: 82.9%, COD: 74.7%). Highly increased antioxidant enzymes (peroxidase and catalase) reduced photosynthesis-negative enzyme (malondialdehyde) activity of plants in CW-G3, which ensured oxygen (O2) and organic carbon (OC) production and successfully released to rhizosphere by well-developed root aeration tissues. Further, CW-G3 enriched higher abundance of genus Saccharimonadales and Flavobacterium, which benefited nitrogen removal. Moreover, as OC, higher contents of maltose in CW-G3 (6.6 ~ 11.1-fold of that in other three CWs), as well as lauramide, choline, triethylamine and urocanic acid contributed to microbial denitrifying. Differently, higher contents of unsaturated fatty acids (linoleic acid and oleic acid) in other three CWs inhibited microbial nitrifying as inhibitors, which also proved by co-occurrent network. Thereby, plant configuration in CW-G3 provided higher O2 and OC contents for bacteria and reduced nitrifying inhibitors, which contributed to higher purifying efficiency. The study promoted the understanding about root exudates' effects on bacteria through plant configurations and improved the purification efficiency of CWs.

Immobilization of chromium enhanced by arbuscular mycorrhizal fungi in semi-aquatic habitats with biochar addition

Arbuscular mycorrhizal fungi (AMF) exhibit great potential in heavy-metal immobilization in semi-aquatic habitats. Under high heavy-metal stress, however, the role of AMF is limited, and the detoxification mechanism of AMF in heavy metals’ stabilization remains unclear. This study investigated the effects of AMF on a wetland plant (Iris pseudacorus) and chromium (Cr) immobilization at different water depths in semi-aquatic habitats with biochar addition. Results showed that AMF increased the physiological and photosynthetic functions in I. pseudacorus under Cr exposures. Besides, AMF alleviated the accumulation of reactive oxygen species and lipid peroxidation by enhancing the antioxidant enzyme activities. AMF and biochar significantly decreased Cr concentrations in outlet water and increased Cr accumulation in I. pseudacorus. Besides, biochar also vastly improved Cr accumulation in the substrate under the fluctuating water depth. AMF reduced Cr bioavailability in the substrate, with Cr (Ⅵ) concentrations and acid-soluble forms of Cr decreased by 0.3–64.5% and 19.0–40.8%, respectively. Micro-proton-induced X-ray emission was used to determine element localization and revealed that AMF improved the nutrients uptake by wetland plants and inhibited Cr translocation from roots to shoots. Overall, this study demonstrated that the interaction between AMF and biochar could significantly enhance the immobilization of high Cr concentrations in semi-aquatic habitats.

Germination niche breadth of invasive Iris pseudacorus (L.) suggests continued recruitment from seeds with global warming.

PremiseUnderstanding recruitment processes of invasive species is central to conservation and management strategies. Iris pseudacorus, an emergent macrophyte, has established invasive populations across a broad global range, and reduces biodiversity in wetland ecosystems. Climate change is altering germination cues, yet studies on the invasion of wetland macrophytes often ignore germination ecology despite its importance to their establishment and spread.MethodsWe explored germination of seeds from invasive I. pseudacorus populations in California in response to seed coat presence or absence, and several environmental factors. Using experimental results in a thermal time model, we derived germination temperature thresholds.ResultsGermination of I. pseudacorus seeds did not require cold or warm stratification, and was not affected by seed coat presence or absence. Germination occurred in the dark, although germinability was two‐ to threefold times greater under light. At constant temperature, thermal time model estimates included 18.3 ± 1.8°C base germination temperature (Tb); 28.2 ± 0.5°C optimal temperature (To); and 41.0 ± 1.7°C ceiling temperature (Tc). Seeds exposed to 36.0°C achieved over 10% germination, and embryos of ungerminated seeds presented 76% viability. Overall, germinability remained relatively low at constant temperatures (≤25%) but was close to 90% under alternating daily temperatures.ConclusionsExposure to diurnally fluctuating temperatures is essential for this species to achieve high germination rates. Our study reveals that I. pseudacorus has a broad germination niche supporting its establishment in a relatively wide range of environments, including at high temperatures more frequent with climate change.

Evaluation of Textile Industry Wastewater Treatment as an Effort to Control River Water Pollution in Central Java

There is an increasing need for clean water because of the growing population. However, the amount of clean water is decreasing due to poor water resource management. Several textile industry processes result in waste. Color, alkalinity, high TSS, high BOD, and some dyes are known to contain chromium elements and are all common characteristics of liquid waste produced by the textile industry. The goal of this study was to assess the performance of textile waste treatment units in Pringsurat Subdistrict, Magelang Regency, Central Java Province, as part of an effort to reduce river water pollution. Quantitative and qualitative methods were used including through surveys and mapping. Groundwater flow maps, and river water and wastewater levels of BOD, COD, TSS, phenol, chromium, ammonia, and sulfide were used as primary data. Unpleasant odors and discoloration of the river were observed. It is recommended that, to reduce the impact of the wastewater, a constructed wetland with a combination of two types of plants, Iris pseudacorus and Thypa angustifolia, should be used.&#x0D; Keywords: Pollution Control, River Pollution, Textile Industry, Wastewater treatment, and Wetland

Some results of the functioning of the Natural Botanical Garden in the Republic of Bashkortostan

In the Republic of Bashkortostan, since 2005, in the Natural Botanical Garden (Kushnarenkovsky district, Mountain Gurovskaya), experiments have been carried out on the introduction of rare and endangered plant species of regional flora into a new natural environment as close as possible to the ecological and phytocenotic conditions of their habitats. To date, the following areas of work have been worked out: creation of collections for the study and conservation of gene pools for 20 rare species (families Alliaceae, Fabaceae, Paeoniaceae and other); creation of long-term self-renewable reserve populations to preserve the gene pool of specific natural populations for Hedysarum razoumovianum, Globularia punctata, Oxytropis hippolyti; creation of uterine plots in order to obtain mass planting and sowing material for reintroduction work for Allium nutans; experience of evacuation to the territory of the Natural Botanical Garden of plants from natural populations doomed to destruction for A. obliquum and Iris pseudacorus. The collections include economically valuable species: ornamental, food, melliferous and medicinal. These plant collections can be used for demonstration and educational purposes.

Effects of Different Inorganic Nitrogen Sources of Iris pseudacorus and Iris japonica on Energy Distribution, Nitrogen, and Phosphorus Removal

High- and low-affinity transport systems are the main pathways for the transportation of NO3– and NH4+ across intracellular membranes. NO3− and NH4+ are assimilated through different metabolic pathways in plants. Fifteen ATP molecules are hydrolyzed in the metabolic process of NO3–; however, only five ATP molecules are hydrolyzed in that of NH4+. In this research, seedlings of Iris pseudacorus and Iris japonica were used as the experimental materials in the NO3–:NH4+ = 30:0, NO3–:NH4+ = 28:2, NO3–:NH4+ = 27:3, NO3–:NH4+ = 15:15, NO3–:NH4+ = 3:27, and NO3–:NH4+ = 0:30 treatments at the 7.5 mmol·L−1 the total nitrogen content (TN). The intracellular free energy was represented by physiological resistance (R) and physiological impedance (Z) according to the Nernst equation and could conveniently and comprehensively determine the cellular metabolic energy (GB). The maximum absorption rate (Vmax) and Michaelis constant (Km) for NH4+ and NO3– uptake were calculated according to the kinetic equation. The results showed that the cellular metabolic energy (GB) of I. pseudacorus was 1 to 1.5 times lower than that of I. japonica at each treatment on the 10th day. The GB values of I. pseudacorus and I. japonica seedlings increased with increasing NH4+ concentration. However, there was a turning point at the NO3–:NH4+ = 15:15 treatment for the cellular metabolic energy of I. pseudacorus and I. japonica. Correlation analysis showed that the value of cellular metabolic energy was negatively correlated with the Vmax and Km for NO3– uptake, whereas it was positively correlated with that for NH4+ uptake. These results demonstrate that the NO3–:NH4+ = 27:3 treatment level was the most suitable for I. pseudacorus and I. japonica. This indicates that the greater cellular metabolic energy is the most suitable for plant growth when the concentration of ammonium or nitrate had no significant difference at treatment. These results provide a simple and rapid solution for removal of nitrogen by determination of cellular metabolic energy.

Iris pseudacorus as precursor affecting ecological transformation of graphene oxide and performance of constructed wetland

The role of plants is largely unknown in constructed wetlands (CWs) exposed to phytotoxic nanomaterials. Present study investigated transformation of graphene oxide (GO) and performance of CWs with Iris pseudacorus as precursor. GO was trapped by CWs without dependence on plants. GO could move to lower substrate layer and present increases on defects/disorders with stronger effects in planted CW. Before adding GO, planted CW achieved better removal both of phosphorus and nitrogen. After adding GO, phosphorus removal in planted CW was 93.23–95.71% higher than 82.55–90.07% in unplanted CW. However, total nitrogen removal was not improved, showing 48.20–56.66% and 53.44–56.04% in planted and unplanted CWs. Plant improved urease, phosphatase, and arylsulfatase, but it decreased β-glucosidase and had less effects on dehydrogenase and catalase. Pearson correlation matrix revealed that plant enhanced microbial interaction with high degree of positive correlation. Moreover, there were obvious shifts in microbial community at phylum and genus level, which presented closely positive action on substrate enzyme activities. The functional profile was less affected due to functional redundancy in microbial system, but time effects were obvious in CWs, especially in planted CW. These findings could provide the basis on understanding role of plants in CWs for treating nanoparticles wastewater.

Heavy metals distribution and accumulation characteristics of 16 species plants on ecological floating-bed

Distribution and accumulation characteristics of copper (Cu), zinc (Zn), mercury (Hg), and lead (Pb) in the aerial and underground parts of 16 species of plants on ecological floating-bed were studied in the present study, and they showed significant differences. Most translocation factors for Cu, Zn, Hg, and Pb were smaller than 1. Coleus blumei had a considerable absorption and accumulation effect on Zn, Hg, and Pb; Hylotelephium erythrostictum had a good absorption and accumulation effect on Zn and Hg. Arundo donax var. versicolor, Lythrum salicaria, and Iris pseudacorus which had remarkable absolute accumulation in the aerial part due to their massive biomass, and were expected to have a promising prospect in applying floating-bed technology.

Contrasted Impacts of Yellow Flag Iris (Iris pseudacorus) on Plant Diversity in Tidal Wetlands within Its Native and Invaded Distribution Ranges

We conducted an intercontinental biogeographic survey to analyze the effects of an invasive plant species in its native and invaded ranges. Our study system included tidal wetlands colonized by Iris pseudacorus L. (yellow flag iris, Iridaceae) along salinity gradients in two estuaries in its native European (Guadalquivir Estuary) and invaded North American (San Francisco Bay-Delta Estuary) ranges. We hypothesized I. pseudacorus would impart more negative community-level impacts on plant species diversity in the invaded range compared to the native range. Our results show that the colonization of Iris pseudacorus has very different effects on the diversity of tidal plant communities in its native and invaded ranges. In the native range, I. pseudacorus promoted plant diversity by increasing evenness and species richness. On the contrary, I. pseudacorus greatly reduced plant diversity in the invaded range, being this reduction higher in those communities with higher species richness and diversity levels. In view of these results, urgent management practices are needed to control and eradicate I. pseudacorus from the inland Sacramento-San Joaquin Delta Estuary since this invasive macrophyte is reducing plant diversity at local and landscape scales.

Removal of perfluoroalkyl acids and dynamic succession of biofilm microbial communities in the decomposition process of emergent macrophytes in wetlands

Perfluoroalkyl acids (PFAAs) are emerging contaminants that pose significant environmental and health concerns. Water–sediment–macrophyte residue systems were established to clarify the removal efficiency of PFAAs, explore possible removal pathways, and profile the dynamic succession of biofilm microbial communities in the decomposition process. These systems were fortified with 12 PFAAs at three concentration levels. Iris pseudacorus and Alisma orientale were selected as the decomposing emergent macrophytes. The removal rates in the treatments with residues of I. pseudacorus (IP) and A. orientale (AO) were 34.4% to 88.9% and 36.5% to 89.9%, respectively, which were higher than those in the control groups (CG) (30.3% to 86.9%), suggesting that decomposition could alter the removal of PFAAs. Sediment made the greatest contributions (preloaded 14.5% to 77.8% of PFAAs in IP, 14.3% to 78.2% in AO, and 27.4% to 71.9% in CG). PFAAs could also be removed by macrophyte residue sorption (0.0190% to 13.0% in IP and 0.016% to 15.6% in AO) and bioaccumulation of residual biofilm (the contributions of biofilm microbes and their extracellular polymeric substances were 0.0110% to 3.93% and 0.918% to 34.4%, respectively, in IP and 0.0141% to 4.65% and 1.49% to 34.1%, respectively, in AO). Significant correlations were observed between sediment/residue adsorption and bioaccumulation of biofilm microbes, and were significantly correlated with perfluoroalkyl chain length (p < 0.05). The dynamic succession of residual biofilm microbial communities was investigated. The largest difference was found at the preliminary stage. The most similar communities were found in AO on day 70 (with specific genera Macellibacteroides and WCHB1-32) and in IP on day 35 (with specific genera Aeromonas and Flavobacterium). This study is useful to understand the removal of PFAAs during the decomposition process, providing further assistance in removing PFAAs during the life cycle of macrophytes in wetlands.

Effects of Graphene Oxide on Atrazine Phytotoxicity Effects of Graphene Oxide on Photosynthetic Response of Iris Pseudacorus to Atrazine Stress and Accumulation of Atrazine in the Plant.

To evaluate combined effects of co-existed pesticides and nanomaterials on aquatic plants, the toxicity of herbicide atrazine (ATZ) on Iris pseudacorus in the presence and absence of Graphene oxide (GO) was investigated using chlorophyll a fluorescence transients. Results showed that GO reduced ATZ accumulation in plant. ATZ or ATZ combined with GO mainly blocked electron transport beyond QA at PSII as indicated by the sharp rise of the J-step level of fluorescence rise kinetics. The pronounced increase in Fm and the loss of I-step were observed when ATZ was at 2.0mg·L- 1 implying the damage on the oxygen evolution complex and PSI. GO at environmentally relevant concentration did not exhibit significant photosynthetic inhibitory effects on I. pseudacorus. GO at 1.0mg·L- 1 promoted photosynthesis of I. pseudacorus under ATZ stress at 2.0mg·L- 1. These result indicated that the presence of GO alleviated the photosynthesis inhibition by ATZ at high levels.

Bioremediation of 27 Micropollutants by Symbiotic Microorganisms of Wetland Macrophytes

Background: Micropollutants in bodies of water represent many challenges. We addressed these challenges by the application of constructed wetlands, which represent advanced treatment technology for the removal of micropollutants from water. However, which mechanisms specifically contribute to the removal efficiency often remains unclear. Methods: Here, we focus on the removal of 27 micropollutants by bioremediation. For this, macrophytes Phragmites australis, Iris pseudacorus and Lythrum salicaria were taken from established wetlands, and a special experimental set-up was designed. In order to better understand the impact of the rhizosphere microbiome, we determined the microbial composition using 16S rRNA gene sequencing and investigated the role of identified genera in the micropollutant removal of micropollutants. Moreover, we studied the colonization of macrophyte roots by arbuscular mycorrhizal fungi, which are known for their symbiotic relationship with plants. This symbiosis could result in increased removal of present micropollutants. Results: We found Iris pseudacorus to be the most successful bioremediative system, as it removed 22 compounds, including persistent ones, with more than 80% efficiency. The most abundant genera that contributed to the removal of micropollutants were Pseudomonas, Flavobacterium, Variovorax, Methylotenera, Reyranella, Amaricoccus and Hydrogenophaga. Iris pseudacorus exhibited the highest colonization rate (56%). Conclusions: Our experiments demonstrate the positive impact of rhizosphere microorganisms on the removal of micropollutants.

Effects of Enrofloxacin on Nutrient Removal by a Floating Treatment Wetland Planted with Iris pseudacorus: Response and Resilience of Rhizosphere Microbial Communities

Constructed wetlands (CWs), including floating treatment wetlands (FTWs), possess great potential for treating excessive nutrients in surface waters, where, however, the ubiquitous presence of antibiotics, e.g., enrofloxacin (ENR), is threatening the performance of CWs. In developing a more efficient and resilient system, we explored the responses of the FTW to ENR, using tank 1, repeatedly exposed to ENR, and tank 2 as control. Plant growth and nutrient uptake were remarkably enhanced in tank 1, and similar phosphorus removal rates (86~89% of the total added P) were obtained for both tanks over the experimental period. Contrarily, ENR apparently inhibited N removal by tank 1 (35.1%), compared to 40.4% for tank 2. As ENR rapidly decreased by an average of 71.6% within a week after each addition, tank 1 took only 4 weeks to adapt and return to a similar state compared to that of tank 2. This might be because of the recovery of microbial communities, particularly denitrifying and antibiotic-resistance genes containing bacteria, such as Actinobacteria, Patescibacteria, Acidovorax and Pseudomonas. After three ENR exposures over six weeks, no significant differences in the nutrient removal and microbial communities were found between both tanks, suggesting the great resilience of the FTW to ENR.

Climatic suitability and compatibility of the invasive Iris pseudacorus L. (Iridaceae) in the Southern Hemisphere: Considerations for biocontrol

Iris pseudacorus L. (Iridaceae) is an emergent macrophyte native to Europe, North Africa and western Asia. Considered invasive in wetland habitats around the world, this species is now the target of a biocontrol programme in the Southern Hemisphere. Native range surveys of the weed led to the selection of the flea beetle, Aphthona nonstriata Goeze (Coleoptera: Chrysomelidae), as a candidate biocontrol agent. An important aspect to consider in weed biocontrol is the ability of an agent to establish and thrive in the environment where it is released. Climatic incompatibility between source and intended release sites can in fact limit the success of a biocontrol programme. In the current study, the potential climatic niche of I. pseudacorus and A. nonstriata in the Southern Hemisphere was analysed. The ecological niche modelling software MaxEnt was used to map the climatic suitability of both organisms across invaded regions in South America, southern Africa and Australasia. Furthermore, occurrence records from each invaded range were used independently to model the climatic compatibility of I. pseudacorus in Europe, in order to prioritize areas of the native range to explore during future surveys for potential biocontrol agents. The models identified areas at high risk of invasion by I. pseudacorus in northern Argentina, Uruguay, southern Brazil and central Chile, as well as numerous provinces of eastern South Africa, Lesotho, southern Australia and New Zealand. Accordingly, the highest climatic suitability for A. nonstriata was predicted across the humid temperate climates of north-east Argentina, Uruguay, southern Brazil, southern South Africa, south-east Australia and New Zealand. These results can eventually be used in future release plans to prioritize areas where establishment and survival of the agent is expected to be highest. At the same time, it may be useful to search the native range of the weed for biological control agents showing high climatic adaptation towards the intended release sites of each invaded range. In this regards, our climatic compatibility models identified high-priority areas across the Mediterranean regions of Italy and southern France, as well as the temperate regions of central and western Europe. Altogether, the current study provides useful new information to tackle the invasion and advance the biocontrol programme of I. pseudacorus in the Southern Hemisphere.