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The article discusses Olzreuter Lake in south-western Germany, highlighting its ecological significance and archaeological relevance. The lake is surrounded by diverse habitats and is part of a Special Area of Conservation. Sediment cores from the lake reveal information about the environmental history of the region, including pollen records dating back to different periods. The research was conducted by various institutions and funded by the Senckenberg Centre for Human Evolution and Paleoenvironment in Tübingen. [Extracted from the article]

Introduction: Freshwater ecosystems are susceptible to invasion by alien macrophytes due to their connectivity and various plant dispersal vectors. These ecosystems often experience anthropogenic nutrient enrichment, favouring invasive species that efficiently exploit these resources. Propagule pressure (reflecting the quantity of introduced individuals) and habitat invasibility are key determinants of invasion success. Moreover, the enemy release hypothesis predicts that escape from natural enemies, such as herbivores, allows alien species to invest more resources to growth and reproduction rather than defense, enhancing their invasive potential. Yet, the combined impact of propagule pressure, herbivory, and nutrient enrichment on the competitive dynamics between invasive alien macrophytes and native macrophyte communities is not well understood due to a paucity of studies. Methods: We conducted a full factorial mesocosm experiment to explore the individual and combined effects of herbivory, nutrient levels, propagule pressure, and competition on the invasion success of the alien macrophyte Myriophyllum aquaticum into a nativemacrophyte community comprising Vallisneria natans, Hydrilla verticillata, and Myriophyllum spicatum. This setup included varying M. aquaticum densities (low vs. high, simulating low and high propagule pressures), two levels of herbivory by the native snail Lymnaea stagnalis (herbivory vs no-herbivory), and two nutrient conditions (low vs. high). Myriophyllum aquaticum was also grown separately at both densities without competition from native macrophytes. Results: The invasive alien macrophyte M. aquaticum produced the highest shoot and total biomass when simultaneously subjected to conditions of high-density intraspecific competition, no herbivory, and low-nutrient availability treatments. Moreover, a high propagule pressure of M. aquaticum significantly reduced the growth of the native macrophyte community in nutrient-rich conditions, but this effect was not observed in nutrient-poor conditions. Discussion: These findings indicate that M. aquaticum has adaptive traits enabling it to flourish in the absence of herbivory (supporting the enemy release hypothesis) and in challenging environments such as intense intraspecific competition and low nutrient availability. Additionally, the findings demonstrate that when present in large numbers, M. aquaticum can significantly inhibit the growth of native macrophyte communities, particularly in nutrientrich environments. Consequently, reducing the propagule pressure of M. aquaticum could help control its spread and mitigate its ecological impact. Overall, these findings emphasize that the growth and impacts of invasive alien plants can vary across different habitat conditions and is shaped by the interplay of biotic and abiotic factors. [ABSTRACT FROM AUTHOR]

Aquatic flora of Dagestan, the diverse region connecting the Caucasian and Aralo-Caspian floristic provinces, received little research effort. Therefore, we conducted two expeditions across aquatic and wetland habitats of Dagestan in June and September 2021 and analyzed public records of aquatic plants from the GBIF database. We report new data on distribution of 35 aquatic vascular plants taxa in Dagestan. A hybrid between Ranunculus peltatus and R. trichophyllus was firstly reported in Russia, although no occurrences of R. peltatus are known in the country. Najas major and hybrid Potamogeton × salicifolius (P. lucens × P. perfoliatus) are new to the Caucasus, and five more species are new to Dagestan (Myriophyllum sibiricum, Najas graminea, Potamogeton pusillus, Typha domingensis, Utricularia minor). [ABSTRACT FROM AUTHOR]

Background: Fatty acids are essential for human health. Currently, there is a search for alternative sources of fatty acids that could supplement such sources as staple crops or fishes. Turions of aquatic plants accumulate a variety of substances such as starch, free sugars, amino acids, reserve proteins and lipids. Our aim is to see if turions can be a valuable source of fatty acids. Methods: Overwintering shoots and turions of aquatic carnivorous plants were collected. The plant material was extracted with hexane. The oils were analyzed using a gas chromatograph with mass spectrometer. Results: The dominant compound in all samples was linolenic acid. The oil content was different in turions and shoots. The oil content of the shoots was higher than that of the turions, but the proportion of fatty acids in the oils from the shoots was low in contrast to the oils from the turions. The turions of Utricularia species were shown to be composed of about 50% fatty acids. Conclusions: The turions of Utricularia species can be used to obtain oil with unsaturated fatty acids. In addition, the high fatty acid content of turions may explain their ability to survive at low temperatures. [ABSTRACT FROM AUTHOR]

Eutrophication due to nutrient addition can result in major alterations in aquatic ecosystem productivity. Foundation species, individually and interactively, whether present as invasive species or as instruments of ecosystem management and restoration, can have unwanted effects like stabilizing turbid eutrophic states. In this study, we used whole-pond experimental manipulations to investigate the impacts of disturbance by nutrient additions in the presence and absence of two foundation species: Dreissena polymorpha (a freshwater mussel) and Myriophyllum spicatum (a macrophyte). We tracked how nutrient additions to ponds changed the prokaryotic and eukaryotic communities, using 16S, 18S, and COI amplicon sequencing. The nutrient disturbance and foundation species imposed strong selection on the prokaryotic communities, but not on the microbial eukaryotic communities. The prokaryotic communities changed increasingly over time as the nutrient disturbance intensified. Postdisturbance, the foundation species stabilized the prokaryotic communities as observed by the reduced rate of change in community composition. Our analysis suggests that prokaryotic community change contributed both directly and indirectly to major changes in ecosystem properties, including pH and dissolved oxygen. Our work shows that nutrient disturbance and foundation species strongly affect the prokaryotic community composition and stability, and that the presence of foundation species can, in some cases, promote the emergence and persistence of a turbid eutrophic ecosystem state. [ABSTRACT FROM AUTHOR]

This study sought to investigate the invasive mechanism of Myriophyllum aquaticum by subjecting it to simulation experiments in varying water temperatures ranging from 0 °C to 30 °C. The results showed that water temperature considerably affected both the growth and reproduction of M. aquaticum. The optimal temperature range for the growth of M. aquaticum was 25‒30 °C. Although the growth of M. aquaticum was inhibited at temperatures between 0‒5 °C, this did not result in mortality. The stem nodes, branches, and diameter reached maximum values over a temperature range of 20‒25 °C. High-temperature stress at 30 °C led to a gradual decrease or disappearance of branches. Compared to the 0 °C, 5 °C, and 30 °C treatment groups, a temperature of 20 °C led to biomass accumulation and significantly higher values. M. aquaticum’s physiological activities were affected by temperature. Except for 10 °C and 15 °C, the catalase activity varied among different water temperatures. M. aquaticum catalase activity was maximal at 5 °C and minimal at 25 °C. Conversely, the synthesis of photosynthetic pigments was highest at 10 °C and 15 °C. The plant’s optimal temperature for growth was between 20 °C and 25 °C. When the temperature was <10 °C, M. aquaticum adapted to the water temperature’s potential damage. This plant has a notable ability to tolerate various temperatures. [ABSTRACT FROM AUTHOR]

Transition metals and their oxide compounds exhibit excellent chemical reactivity; however, their easy agglomeration and high cost limit their catalysis applications. In this study, an interpolation structure of a Myriophyllum verticillatum L. biochar-supported Mn/Mg composite (Mn/Mg@MV) was prepared to degrade triphenyl phosphate (TPhP) from wastewater through the activating periodate (PI) process. Interestingly, the Mn/Mg@MV composite showed strong radical self-producing capacities. The Mn/Mg@MV system degraded 93.34% TPhP (pH 5, 10 μM) within 150 min. The experimental results confirmed that the predominant role of IO3· and the auxiliary ·OH jointly contributed to the TPhP degradation. In addition, the TPhP pollutants were degraded to various intermediates and subsequent Mg mineral phase mineralization via mechanisms like interfacial processes and radical oxidation. DFT theoretical calculations further indicated that the synergy between Mn and Mg induced the charge transfer of the carbon-based surface, leading to the formation of an ·OH radical-enriched surface and enhancing the multivariate interface process of ·OH, IO3, and Mn(VII) to TPhP degradation, resulting in the further formation of Mg PO4 mineralization. [ABSTRACT FROM AUTHOR]

The unregulated dismantling and improper disposal of electronic waste lead to severe soil contamination by polychlorinated biphenyls (PCBs). Constructed wetlands (CWs) play an important role in PCBs removal as a result of the co-existence of anaerobic and aerobic conditions. However, the effects and mechanisms of different PCBs concentrations in soils on plant uptake and PCBs degradation within CWs are unclear. We evaluated the uptake and degradation of PCBs at different concentrations by Myriophyllum aquaticum (Vell.) Verdc. Planting significantly increased PCBs removal by 8.70% (p < 0.05) in soils with 1500 and 2500 μg/kg PCBs, whereas no significant effect was observed at 500 and 1000 μg/kg. PCBs levels did not significantly affect plant growth and PCBs accumulation. The contribution of plant uptake to PCBs removal was only 0.10–0.12%, indicating that microbial degradation was the dominant pathway for PCBs removal after planting with M. aquaticum. In the treatments with PCBs ≥ 1500 μg/kg, M. aquaticum increased the microbial population, altered the microbial community structure and enriched PCB-degrading bacteria. Functional prediction revealed that microbes in M. aquaticum rhizosphere secreted more peroxidase and glycosyltransferase than non-plant control, which were likely involved in PCBs metabolism. [ABSTRACT FROM AUTHOR]

This study designed surface flow constructed wetlands (SFCWs) with Myriophyllum aquaticum (M. aquaticum) to evaluate how different influent C/N ratios (0:1 (C0N), 5:1 (C5N), 10:1 (C10N), and 15:1 (C15N)) affect pollutant removal, greenhouse gas (GHG) emissions, and microbial communities. The results showed that effluent ammonia nitrogen ( N H 4 + -N), nitrate nitrogen ( N O 3 − -N), and total nitrogen (TN) concentrations decreased, but effluent chemical oxygen demand (COD) concentration increased with increasing influent C/N ratios. The highest removal rates of TN (73.17%) and COD (74.56%) were observed with C5N. Regarding GHG emissions, a few changes in CO2 fluxes were caused by the influent C/N ratio, whereas CH4 fluxes obviously increased with the increasing influent C/N ratio. The highest N2O emission occurred with C0N (211.03 ± 44.38 mg-N·m−2·h−1), decreasing significantly with higher C/N ratios. High-throughput sequencing revealed that different influent C/N ratios directly influenced the microbial distribution and composition related to CH4 and N2O metabolism in SFCWs. The highest abundance (46.24%) of denitrifying bacteria (DNB) was observed with C5N, which helped to achieve efficient nitrogen removal with a simultaneous reduction in N2O emissions. Methanogen abundance rose with higher C/N ratios, whereas methanotrophs peaked under C5N and C10N conditions. Additionally, the random forest model identified influent C/N ratio and Rhodopseudomonas as primary factors influencing CH4 and N2O emissions, respectively. This highlights the importance of the influent C/N ratio in regulating both pollutant removal and GHG emissions in constructed wetlands. [ABSTRACT FROM AUTHOR]

Eutrophication due to nutrient addition can result in major alterations in aquatic ecosystem productivity. Foundation species, individually and interactively, whether present as invasive species or as instruments of ecosystem management and restoration, can have unwanted effects like stabilizing turbid eutrophic states. In this study, we used whole-pond experimental manipulations to investigate the impacts of disturbance by nutrient additions in the presence and absence of two foundation species: Dreissena polymorpha (a freshwater mussel) and Myriophyllum spicatum (a macrophyte). We tracked how nutrient additions to ponds changed the prokaryotic and eukaryotic communities, using 16S, 18S, and COI amplicon sequencing. The nutrient disturbance and foundation species imposed strong selection on the prokaryotic communities, but not on the microbial eukaryotic communities. The prokaryotic communities changed increasingly over time as the nutrient disturbance intensified. Post-disturbance, the foundation species stabilized the prokaryotic communities as observed by the reduced rate of change in community composition. Our analysis suggests that prokaryotic community change contributed both directly and indirectly to major changes in ecosystem properties, including pH and dissolved oxygen. Our work shows that nutrient disturbance and foundation species strongly affect the prokaryotic community composition and stability, and that the presence of foundation species can, in some cases, promote the emergence and persistence of a turbid eutrophic ecosystem state.

Background: Fatty acids are essential for human health. Currently, there is a search for alternative sources of fatty acids that could supplement such sources as staple crops or fishes. Turions of aquatic plants accumulate a variety of substances such as starch, free sugars, amino acids, reserve proteins and lipids. Our aim is to see if turions can be a valuable source of fatty acids. Methods: Overwintering shoots and turions of aquatic carnivorous plants were collected. The plant material was extracted with hexane. The oils were analyzed using a gas chromatograph with mass spectrometer. Results: The dominant compound in all samples was linolenic acid. The oil content was different in turions and shoots. The oil content of the shoots was higher than that of the turions, but the proportion of fatty acids in the oils from the shoots was low in contrast to the oils from the turions. The turions of Utricularia species were shown to be composed of about 50% fatty acids. Conclusions: The turions of Utricularia species can be used to obtain oil with unsaturated fatty acids. In addition, the high fatty acid content of turions may explain their ability to survive at low temperatures.

Although organophosphate esters (OPEs) and nitrogen (N) are normally present in aquatic environments, the effects of the plant uptake, accumulation, and translocation of OPEs in different levels of N remain ambiguous. To better understand these processes, watermifoil (Myriophyllum aquaticum L.) as tested plant was chosen to investigate the effects of different N levels on the uptake and translocation of OPEs by plants in matched water-sediment-plant samples. After two months, we found the root-water concentration factors, root-sediment concentration factors, and translocation factors (TFs) were significantly changed with the levels of N (p < 0.05), implying that the presence of N could alter uptake, accumulation, and translocation of OPEs in M. aquaticum, particularly the process of root absorption. Low concentrations of N could remarkably promote the uptake of OPEs by M. aquaticum. However, when the concentrations of N in water were higher than 200 mg/L, the plants' growth and OPE accumulation by M. aquaticum were obviously inhibited with the elevated N contents. Moreover, the enrichment and environmental transport of OPEs in M. aquaticum seemed to be closely associated with physicochemical parameters; the octanol-water partition coefficient had significant relationships with measured organic carbon-normalized sediment-water partition coefficients and TFs in the present study. Additionally, the substituents and structures of OPEs could also affect the accumulation and translocation of OPEs in M. aquaticum, including the chlorination degree and alkyl chain length. This study could improve our understanding of uptake and translocation of OPEs in aquatic plants under different levels of N. [ABSTRACT FROM AUTHOR]

Myriophyllum aquaticum has shown potential allelopathic effects for the biocontrol of cyanobacteria and cyanotoxins. However, the composition of allelochemicals and their biological effects may be influenced by seasonal changes. In this study, we investigated the impact of aqueous extracts of M. aquaticum collected in different seasons on the growth of Microcystis aeruginosa and the concentration of microcystin-LR. Plant samples were extracted using ultrasound cycles in aqueous solutions, and extracts at varying concentrations (0.1, 10, and 100 mg/L) and a control treatment were inoculated with M. aeruginosa, and cell growth was analyzed using a Neubauer chamber. Photosynthetic pigment quantification was used to measure physiological effects and liquid chromatography was used to evaluate the microcystin-LR concentrations. The extracts of plants collected during autumn and winter exhibited higher inhibition of M. aeruginosa growth and a reduction in photosynthetic pigments compared to those collected during spring and summer. These results can be explained by the higher presence of phenolic compounds in the composition of extracts from autumn and winter. Microcystin-LR concentrations were decreased at 10 and 100 mg/L, with the highest efficiency observed in autumn, while spring showed lower efficiency. Our findings suggest that M. aquaticum extracts have inhibitory potential on M. aeruginosa, particularly during the autumn season, making them a promising nature-based solution for the biocontrol of harmful algal blooms. [ABSTRACT FROM AUTHOR]

Reclaimed water produced via the advanced treatment of domestic wastewater has broad application prospects for reuse in urban rivers, while the nutrients in reclaimed water, especially nitrogen and phosphorus, lead to eutrophication or ecological impacts. Submerged plants are preferred as an enhanced technology used at reclaimed water recharge sites for both water quality improvement purposes and ecological conservation functions. In this study, which adopted the typical submerged plant Myriophyllum verticillatum (M. verticillatum) as its experimental object, experiments were carried out in an illumination incubator without a substrate and under hydrostatic conditions to investigate the water purification effects and mechanisms of action of M. verticillatum at different planting densities. The analysis showed that the group with a wet weight of 2.5 g L−1 had the best growth status and the best overall performance with respect to improvements in water quality indicators, including COD, nitrogen, and phosphorus, as well as demonstrating excellent uptake and synergistic effects in the process of removing nitrogen and phosphorus. The contributions of natural effects, the uptake and enrichment by M. verticillatum itself, and the synergistic effects during the nitrogen and phosphorus removal process were quantified. Furthermore, 16S rRNA gene sequencing was used to determine the surface-attached bacterial colonies of M. verticillatum, to analyze their population diversity, and to identify environmental functional genera. In conclusion, an appropriate density of M. verticillatum can improve water quality and provide a suitable environment for the survival and growth of relevant environmentally functional microorganisms, effectively removing nitrogen and phosphorus through its own absorption and synergistic effects. [ABSTRACT FROM AUTHOR]

To clarify the sorption mechanism and removal efficiency of PAHs by waste biomass-based magnetic sorbents, the sorption performance of magnetic Myriophyllum aquaticum biomass (MMaB) for PAHs was studied. The structural characteristics and magnetic properties of MMaB were measured by FTIR, SEM–EDS, XRD and VSM. Batch experiments were carried out to evaluate the effects of contact time, initial concentration and properties of PAHs, pH, ionic strength and temperature on PAH sorption. The results showed that the sorption of seven PAHs achieved equilibrium at approximately 4–6 h, which fit well to the pseudo-second-order kinetic model. The isotherms followed the Freundlich model and linear model well, indicating that the sorption process was controlled by chemisorption. The distribution parameter (Kd) values were 91.3, 563.7, 1010.5, 2917.8, 2706.6, 9046.8 and 15969.0 L·kg−1 for naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, pyrene, and fluoranthene on MMaB, respectively, following the order of their hydrophobicity (e.g., Kow). A positive correlation was obtained: logKd = 0.8091logKow + 1.7034. Water chemical properties such as pH and ionic strength had no obvious effect on PAH removal. The spontaneity, feasibility and exothermic properties of PAH removal by MMaB were explained from thermodynamic point of view. The as-prepared MMaB sorbent underwent four consecutive sorption cycles and had good cycling performance. These studies indicate that MMaB has great potential as an easily-prepared, easy-to-operate and efficient biosorbent to remove PAHs from wastewater. [ABSTRACT FROM AUTHOR]

Parrot-feather (Myriophyllum aquaticum) is an aquatic plant in the water milfoil family native to South America. It is widely distributed across North America, Europe, Asia, Australasia, and Africa as an invasive species. Outside of its native range, parrot-feather is regarded as a troublesome weed, due to its ability to grow quickly and clog or stagnate shallow waterways. We report six sightings of parrot-feather in the state of Massachusetts, USA from 2006 to 2017 compiled from state-organized surveys. Approaches to control this invasive species, such as physical removal, chemical treatment, and potential biological agents, are also discussed in this report, with specific recommendations made to expand monitoring efforts in Massachusetts and control newly detected populations. [ABSTRACT FROM AUTHOR]

In order to explore the environmental behavior of organophosphate esters (OPEs) in aquatic environment, the accumulation and distribution of OPEs in water, sediment, and plant were investigated. In this study, watermifoil (Myriophyllum aquaticum) were exposed with ten OPEs for concentrations of 200 ng/g, 500 ng/g, 1000 ng/g, and 2000 ng/g, respectively. The concentrations of Σ10OPEs in rhizosphere sediment were higher than those in non-rhizosphere sediment, demonstrating that rhizosphere processes tend to transport OPEs into the rhizosphere sediment. Most of the selected OPEs were not in equilibrium between water and sediment, and trend to retain in sediment. In addition, OPEs with relatively higher hydrophobicity had trend to retained in Myriophyllum aquaticum roots, whereas OPEs with lower hydrophobicity were more likely transported to shoots. In this study, octanol-water partition coefficient (KOW) had significantly positive correlations with organic carbon-normalized soil-water partition coefficients (KOC) and root-water concentration factors (RWCFs), but KOW was negatively correlated with translocation factors (TFs). Moreover, the substituent types and initial levels of OPEs also have impacts on the plant uptake and accumulation. These observations will improve our understanding of the distribution and translocation of OPEs in aquatic environment. [ABSTRACT FROM AUTHOR]

With the rapid expansion of livestock production, the amount of livestock wastewater accumulated rapidly. Lack of biodegradable organic matter makes denitrification of livestock wastewater after anaerobic digestion more difficult. In this study, Myriophyllum aquaticum constructed wetlands (CWs) with efficient nitrogen removal performance were established under different carbon/nitrogen (C/N) ratios. Analysis of community composition reveals the change of M. aquaticum CWs in microbial community structure with C/N ratios. The proportion of Proteobacteria which is one of the dominant phyla among denitrifier communities increased significantly under low C/N ratio conditions. Besides, to obtain cultivable denitrifier that could be added into CWs in situ, 33 strains belonging to phylum Proteobacteria were isolated from efficient M. aquaticum CWs, while the best-performing denitrification strain M3-1 was identified as Bacillus velezensis JT3-1 (GenBank No. CP032506.1). Redundancy analysis and quadratic models showed that C/N ratio had significant effects on disposal of nitrate (NO 3 −-N) and the strains isolated could perform well in denitrification when C/N ratio is relatively low. In addition, they have relatively wide ranges of carbon sources, temperature and a high NO 3 − removal rate of 9.12 mg/(L·hr) at elevated concentrations of 800 mg/L nitrate. Thus, strains isolated from M. aquaticum CWs with low C/N ratio have a practical application value in the treatment of nitrate-containing wastewater. These denitrifying bacteria could be added to CWs to enhance nitrogen removal efficiency of CWs for livestock wastewater with low C/N ratio in the future. [Display omitted] [ABSTRACT FROM AUTHOR]

Through excellent absorption and transformation, the macrophyte Myriophyllum (M.) aquaticum can considerably remove phosphorus from wastewater. The results of changes in growth rate, chlorophyll content, and roots number and length showed that M. aquaticum could cope better with high phosphorus stress compared with low phosphorus stress. Transcriptome and differentially expressed genes (DEGs) analyses revealed that, when exposed to phosphorus stresses at various concentrations, the roots were more active than the leaves, with more DEGs regulated. M. aquaticum also showed different gene expression and pathway regulatory patterns when exposed to low phosphorus and high phosphorus stresses. M. aquaticum's capacity to cope with phosphorus stress was maybe due to its improved ability to regulate metabolic pathways such as photosynthesis, oxidative stress reduction, phosphorus metabolism, signal transduction, secondary metabolites biosynthesis, and energy metabolism. In general, M. aquaticum has a complex and interconnected regulatory network that deals efficiently with phosphorus stress to varying degrees. This is the first time that the mechanisms of M. aquaticum in sustaining phosphorus stress have been fully examined at the transcriptome level using high-throughput sequencing analysis, which may indicate the direction of follow-up research and have some guiding value for its future applications. [ABSTRACT FROM AUTHOR]

This research aimed to verify the identification and distribution of Myriophyllum sibiricum in Lithuania. The study was based on a revision of available herbarium specimens and information from archival materials and literature sources. A total of 134 herbarium specimens of Myriophyllum, mainly initially identified as Myriophyllum spicatum, were examined. After revision of herbarium specimens, 101 of these were identified as Myriophyllum sibiricum. The remaining 33 herbarium specimens were tentatively determined as hybrids Myriophyllum sibiricum × Myriophyllum spicatum. None of the specimens were identified as Myriophyllum spicatum. The distribution of Myriophyllum sibiricum is related mainly to standing waters of upland regions, while localities of putative hybrid scattered throughout the area and associated with upland lakes and river stretches. The morphological features of the leaves (number of segments pairs and its angle with the central axis, occurrence of glands at the base of young leaves and in axils of leaves segments) are helpful to distinguish typical specimens of Myriophyllum sibiricum from Myriophyllum spicatum, however useless for their separation from the hybrid. This study revealed that further research on Myriophyllum sibiricum, Myriophyllum spicatum and their putative hybrid must apply morphological and molecular methods. [ABSTRACT FROM AUTHOR]

The contamination of nanoplastics (NPs) and heavy metals (HM) in water bodies has caused widespread concern, while their effects on submerged plants are poorly reported. Polystyrene nanoplastics (PSNPs) and arsenic (As) were used to assess their toxicity on Myriophyllum verticillatum L. via the orthogonal experiments. PSNPs significantly reduced the accumulation of As (17.24%–66.67%) in plant. Single As and high As-PSNPs treatments significantly inhibited plant growth, with a maximum reduction of 70.09% in the growth rate. The mineral nutrient content was significantly affected by PSNPs and As treatments. The antioxidant system was significantly inhibited, which was more pronounced in the roots. Similar findings were observed for soluble protein and soluble sugar. Some organic acids and amino acids showed down-regulation at high concentrations of As, leading to a decrease in the content of the mineral element and down-regulation of antioxidant enzyme synthesis. Furthermore, PSNPs could alleviate As toxicity under 0.1 mg/L As treatment but exacerbate As toxicity at 1 mg/L As dose. This study has important implications for the study of submerged plants exposed to co-contamination of microplastics and heavy metals, as well as the possible ecological risk assessment in freshwater. [Display omitted] • Interaction of As and PSNPs differs at different As concentrations. • Negative effects were mainly due to As exposure. • Single As and co-exposure affected the physicochemical properties of M. verticillatum. • M. verticillatum responded to stress by regulating amino acids and organic acids. [ABSTRACT FROM AUTHOR]

The paddy field ecosystem and diversified plant food resources in the middle and late Liangzhu Culture were revealed at the Zhumucun site. Based on pollen and phytolith records, this paper presents local vegetation landscape of the site: (1) evergreen-deciduous broad-leaved forests dominated by Quercus , Castanopsis , and Ulmus distributed on the nearby hills, (2) terrestrial herbs represented by Poaceae plants tend to expand on the plain, (3) aquatic plants such as Typha , Trapa , Myriophyllum and Euryale ferox grew in rivers and lakes, and (4) plants such as Phragmites australis , Echinochloa , Polygonum lapathifolium , Haloragidaceae, Rumex , Cyperus , Cyperaceae, and Polygonaceae were distributed in and around the wetland. Water activities tended to be intense, and the climate was generally warm and humid with short-term anomalously cold or wet fluctuations. This is in line with the characteristics of environmental changes revealed by regional natural accumulations. In this conditions, local rice ecosystem was recorded with diachronic changes. [ABSTRACT FROM AUTHOR]

Due to the lack of fresh water, the purification of polluted water is of utmost importance and places a significant financial burden on countries. The effect of Myriophyllum spicatum and Lemna gibba on nitrate absorption in an area of the Tigris River has been investigated in the light of the low cost and ease of application of aquatic plants in purifying water pollution. Aquarium experiments were designed with three treatments, three replicates, and a closed flow. In the aquarium, the biological requirements for the growth of the studied plants were met. The residence time was determined to be 36 days, and nitrate changes were recorded every three days, 12 times. Except for periods 3 and 4, there were significant differences in the rate of nitrate absorption between the studied plants in all treatments (P < 0.05). At the end of the 12th period, M. spicatum and L. gibba had contaminant removal efficiency of 83.31% and 86.27%, respectively. L. gibba ability to utilize nitrate as a nutrient was demonstrated by its significantly increased dry weight at the end of the experiment (P < 0.05). In the current study, the significant difference between the average levels of nitrate in the samples and the control sample indicates the presence of a factor other than bacterial decomposition, namely the presence of plants. According to the findings, these macrophytes are viable for reducing nitrate and organic matter loads in polluted waters. Controlling these macrophytes, so that the nutrients in their tissues do not return to the environment during decomposition is necessary to improve water quality and maintain the achieved quality. [ABSTRACT FROM AUTHOR]

We studied temporal variations in phenolic compounds from the hydrophyte Myriophyllum aquaticum collected from a shallow lake. The effects of macrophyte-conditioned medium containing phenols with other compounds and phenols only as well as plant tissue extracts were tested on the survival and reproduction of the rotifer Plationus patulus. Apical tissue of the hydrophyte had the highest levels of total phenols. Rotifers in controls, and those exposed to phenols from the macrophyte-conditioned medium grew rapidly within two weeks, but cultures exposed to phenols extracted from the apical region took longer. Age-specific survival of P. patulus showed a rapid decline within one week when exposed to plant extracts compared to conditioned medium. The average lifespan of P. patulus was longer in the macrophyte-conditioned medium as compared to the controls, but shorter in the aqueous plant extract. Gross and net reproductive rates showed similar trends, wherein the controls had significantly higher values than those exposed to plant extracts, but increased with the conditioned medium only at the two lower concentrations tested. The demographic response of rotifers exposed to phenols only from the macrophyte-conditioned medium differed from those of the macrophyte-conditioned medium containing both phenolic and non-phenolic compounds. Macrophyte phenolic compounds influenced the survival and reproduction of P. patulus but depended on the other chemicals released into the medium. [ABSTRACT FROM AUTHOR]

Guizhou province, located in the southwest China, is one of the richest biodiversity regions, meanwhile, is also one of the hardest-hit areas by alien invasive species. A comprehensive understanding of the invasive alien plants species composition and distribution can provide a scientific basis for the prevention, early warning and integrated management, to improve the ability of alien invasive species prevention and control. In this study, Guanling Buyi and Miao autonomous county, located in the central Guizhou province, and Huishui county, located in the south-central Guizhou province were selected as the investigation sites. Investigation was conducted in 74 sampling sites of Guanling county and 64 sampling sites of Huishui county using quadrat sampling method, to figure out the species composition, obtain the distribution pattern information (habitats and distribution frequency), then analyze their origin, life type by referring to the literature. In this study, 24 families 56 species of agricultural alien invasive plants were found through field investigation, among which Asteraceae was the dominant family (Guanling: 29.55%, Huishui: 33.33%), followed by Amaranthaceae (Guanling: 13.64%, Huishui: 11.11%), Fabaceae (Guanling: 6.82%, Huishui: 6.67%), Solanaceae (Guanling: 6.82%, Huishui: 4.44%), with mainly herbaceous species (Guanling: 80.85%, Huishui: 86.96%). The escaped Verbena bonariensis Linnaeus and Myriophyllum aquaticum Verdcourt were found in Guizhou for the first time in the wild, confirming their invasive characteristics. Furthermore, Ageratina adenophora (Sprengel) R. M. King & H. Robinson, Bidens pilosa Linnaeus, Erigeron annuus (Linnaeus) Persoon, Alternanthera philoxeroides (Martius) Grisebach, Erigeron canadensis Linnaeus, Geranium carolinianum Linnaeus, Galinsoga parviflora Cavanilles were classified as malignant agricultural alien invasive plants in these two counties, which widely distributing in the sampling sites. Agricultural alien invasive plants had adapted to various habitats and mainly distributed in the frequently anthropogenic disturbance habitats including wastelands, farmlands, roadsides, which had caused threats to the agroecosystem, human activities and natural ecosystems. The alien invasive plants has great species diversity, wild distribution range, strong adaptability, fast reproduction speed and strong reproductive ability in this two counties. Authors suggest that people should take the systematically investigation of the agricultural alien invasive plants in Guizhou province, and strengthen the monitoring and dynamic spread trend research of malignant alien invasive species, to provide scientific basis for the prevention, early warning and integrated management of alien invasive plants. [ABSTRACT FROM AUTHOR]

Considering the vital role of rooted macrophytes in the aquatic ecosystem, validating assumptions on the interactive effects of herbicides with different modes of action at an environmentally relevant mixture ratio is necessary. We investigated the effects of diflufenican (a carotenoid biosynthesis inhibitor) and iodosulfuron‐methyl‐sodium (IMS; an acetolactate synthase inhibitor) in a 14‐day growth inhibition experiment with Myriophyllum spicatum, wherein single compounds and their combination were tested in parallel (n = 84). The assessment was done using three different methods: significance testing, model deviation ratio (MDR), and mixture interaction factor (MIF). Interactions relative to both concentration addition and independent action were assessed via significance testing. This revealed that diflufenican and IMS acted antagonistically relative to both models for fresh weight and total shoot length (p < 0.05) and that there was slight synergism for the number of side shoots (p < 0.001) relative to concentration addition. The MDR and MIF can only assess interactions relative to the concentration addition model. According to MDR, the mixture appeared to show no interaction (neither antagonistic nor synergistic), whereas the MIF method revealed that the compounds acted antagonistically for fresh weight and that there was a slight synergism for total shoot length and number of side shoots. We conclude that inferences about mixture toxicity interactions are method‐ and endpoint‐dependent, which can have implications for regulatory mixtures assessment. Environ Toxicol Chem 2022;41:2209–2220. © 2022 SETAC [ABSTRACT FROM AUTHOR]

In this work, we evaluated whether the species Myriophyllum aquaticum (Vell.) Verdc. can be a promising material for devising reliable eco-toxicological tests for Cd-contaminated waters. Plants of M. aquaticum were exposed to Cd, using different concentrations (1 mg L−1, 2.5 mg L−1, 5 mg L−1, and 10 mg L−1; experiment 1) and exposure times (2.5 mg L−1 for 3 days, 7 days, 14 days, and 21 days; experiment 2). Plant growth and Cd accumulation were monitored during the treatment period, and Cd genotoxicity was assessed by analyzing Cd-induced changes in the AFLP fingerprinting profiles using famEcoRI(TAC)/MseI(ATG) and hexEcoRI(ACG)/MseI(ATG) pairs of primers. Root and shoot growth was reduced already at the lowest Cd concentration used (about 20% reduction for roots and 60% for shoots at 1 mg L−1; experiment 1) and after 7 days (about 50% reduction for roots and 70% for shoots; experiment 2). The primer combinations produced 154 and 191 polymorphic loci for experiments 1 and 2, respectively. Mean genetic diversity (He) reduction among the treatment groups was observed starting from 2.5 mg L−1 (He 0.211 treated vs 0.236 control; experiment 1) and after 3 days (He 0.169 treated vs 0.261 control; experiment 2), indicating that results obtained from AFLP profiles did not match with plant growth measurements. Therefore, our results showed that M. aquaticum proved to be a suitable model system for the investigation of Cd genotoxicity through AFLP fingerprinting profile, whereas the more classic eco-toxicological tests based only on biometric parameters could not correctly estimate the risk associated with undetected Cd genotoxicity. [ABSTRACT FROM AUTHOR]

A confusingly labeled water-milfoil of obscure status, known only in cultivation, is here formally described as a new species, Myriophyllum rubricaule Valk. & Duist. sp. nov. This species has fully replaced M. aquaticum in the horticultural trade in Europe since the addition of M. aquaticum to the list of invasive alien species of Union concern (EU regulation no. 1143/2014) in 2016. This manuscript provides a morphological description of M. rubricaule sp. nov., and its distinction from M. aquaticum is further supported by molecular data (chloroplast and nuclear loci).

Myriophyllum aquaticum (M. aquaticum), as a Cd-highly enriched and tolerant species, has greater application in phytoremediation of Cd-polluted waters. Mechanisms of Cd uptake and transport of M. aquaticum were comprehensively investigated in this work. Transport direction of Cd was observed both from the roots to the aboveground and vice versa. The aboveground can be harvested during vigorous growth and flowering periods, further improving the efficient phytoremediation of Cd-polluted wastewater. Moreover, analysis of transpiration inhibition, low-temperature treatment and metabolic inhibition indicated that the uptake and transport of Cd by M. aquaticum can be achieved via the coexistence of the free diffusion-dominated apoplast pathway dominated by transpiration and the "cellular pathway" dominated by active absorption, with the active energy-demanding cellular pathway playing a dominant role. The obtained results have important implications in the in-depth exploration of uptake, transport and distribution mechanisms of heavy metals during phytoremediation of aquatic plants. [Display omitted] • Transport direction of Cd was observed both from the roots to the aboveground and vice versa. • M. aquaticum had higher capacity for aboveground uptake and transport of Cd in vigorous growth and flowering periods. • Harvest of the aboveground of M. aquaticum during critical periods can improve the phytoremediation efficiency of Cd. • Cd uptake and transport of M. aquaticum were dominated by the active energy-demanding cellular pathway. [ABSTRACT FROM AUTHOR]

Combined use of in situ passivation and macrophytes is a valuable technology that exerts remarkable effects on aquatic systems. However, the effectiveness and ecological functions of this combined technology for macrophytes-dominated eutrophic (MDE) lakes with organophosphorus-controlled internal phosphorus (P) loading were poorly understood. In this study, aquatic simulation experiments were performed to study the combination of La-modified materials (LMM; La-modified bentonite (LMB), and La/Al co-modified attapulgite (LAA)) with macrophytes (Myriophyllum verticillatum L. (MVL), Hydrilla verticillata (Linn. f.) royle (HVR), and Ceratophyllum demersum L. (CDL)) for the control of P mobility in the water column, and to investigate the passivator effects on the physiological characteristics of macrophytes. The mineralization of organophosphates (BD−Po, HCl−Po, and Res−Po) is an important factor for maintaining high internal P loadings and overlying water P concentrations in the experiments. Compared with individual treatment groups, the reduction of internal P release flux and porewater SRP concentrations was more obvious in the combined treatments. Moreover, the redox-sensitive P forms transformation is more pronounced in the surface sediments. In the LAA+M group, internal P release flux was reduced by 55% and 55% compared with individual passivators and macrophytes retreatment groups, respectively. In contrast, the LMB+M group decreased by 16% and 46%, respectively. Simultaneously, LMM had less effect on macrophytes traits compared with individual macrophytes group and enhanced the absorption of phosphate by macrophytes. The phosphate content of macrophytes in the LAA+M and LMB+M groups increased by 24% and 11%, respectively, in comparison with the individual macrophytes group. Results concluded that the combination of passivator and macrophytes enhanced the effect of ecological restoration and exerts a synergistic effect on internal P pollution with macrophytes. [ABSTRACT FROM AUTHOR]

Myriophyllum aquaticum (M. aquaticum) is a commonly used aquatic macrophyte for water purification and could be utilized as animal food. However, the high water content of M. aquaticum makes it difficult for long-term preservation, which leads to challenges as an ideal animal feed ingredient. The storage of Silage for long periods may be a proper method to solve the problem. In the present paper, we assess the effects of lactic acid bacteria Lactobacillus buchneri (LB), Lactobacillus plantarum (LP), or their combination on fermentation and microbial communities during the ensiling of M. aquaticum silage. The results show that the LP-treated silage displays a higher lactic acid concentration than that in the control silage. Both LB and LP increased the abundance of Lactobacillus, but decreased the abundance of Serratia and Prevotella_9 in M. aquaticum silage after 60 days of ensiling. Both LB and LP increased the diversity and richness of fungi. Therefore, the inoculation of LP improved silage fermentation during ensiling. These results show that the inoculation of lactic acid bacteria improves the fermentation quality of M. aquaticum silage, which makes it possible for the application of M. aquaticum to animal forage in the future. [ABSTRACT FROM AUTHOR]

Efficient management of invasive species benefits from understanding patterns of persistence and change over time. In this study, we compare distribution and abundance of the invasive macrophyte parrotfeather (Myriophyllum aquaticum) in an unregulated river system between the time near its presumed introduction and 20 years later. Initial surveys were conducted in 1996–1997, and were repeated in 2015–2016 using similar methodology. Moderate increases in the proportion of river kilometers with parrotfeather between the two periods were observed, but the distribution of sites with low, medium, and high abundance remained consistent, with small numbers of sites in either period having well-established extents of parrotfeather. The distributional extent has moved downstream, with the most upstream and downstream presences shifted by 17 and 28 river kilometers, respectively; however, parrotfeather remains sparse in the lower reaches below the historical downstream extent. Sites with high abundance and stable presence over time are in the intermediate segment of the river, indicating longitudinal and hydrologic controls on distribution. In contemporary sites, area of parrotfeather cover was associated with larger, deeper habitats, whereas dominance of parrotfeather occurred in smaller sites having uniformly shallow depth and low bank slopes. Sites where both abundance and dominance were low had dense canopy cover. Our results demonstrate that landscape and site-level characteristics restrict establishment and persistence of parrotfeather, and that hydrologic alterations to stabilize flow regimes and land use changes should be considered for their potential to increase presence of parrotfeather and other invasive aquatic plants in dynamic floodplain habitats. [ABSTRACT FROM AUTHOR]

BACKGROUND: Hybrid watermilfoil is becoming more prevalent in many lakes where the invasive Eurasian (Myriophyllum spicatum, EWM) and native northern watermilfoil (M. sibiricum) co‐occur. These Eurasian and northern watermilfoil hybrids (HWM) grow 30% faster and in many cases are less sensitive to 2,4‐dichlorophenoxy acetic acid (2,4‐D) than either parent. The mechanism(s) impacting 2,4‐D tolerance in these hybrids was investigated by comparing the absorption, translocation, metabolism, and desorption of two 2,4‐D formulations in EWM and HWM. RESULTS: 2,4‐D absorption in EWM and HWM was 5.7 and 7.9 times the external herbicide concentration determined by the plant concentration factor, a metric used to determine herbicide bioaccumulation, and 2,4‐D butoxyethyl ester absorption was 35.6 and 52.1 times the external concentration in EWM and HWM, respectively. Herbicide bioaccumulation was greater in HWM than in EWM. Herbicide translocation to HWM roots was limited at 192 HAT and herbicide desorption in HWM was slightly lower than EWM. No differences were found in herbicide metabolism between the two plant species. CONCLUSION: 2,4‐D resistance in HWM is not due to non‐target‐site resistance as no differences in herbicide absorption, translocation, desorption and/or metabolism were identified; therefore, target‐site resistance is the most likely resistance mechanism. More research is needed to identify the molecular basis for the 2,4‐D‐resistant trait in HWM. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Resulting from the synopsis of Mandevilla Lindl. (Apocynaceae) in the states of Goiás and Brasília, Brazil, lectotypes are designated for 33 names: Amblyanthera versicolor (Stadelm.) Müll. Arg. var. stenosolen Müll. Arg., Angadenia reticulata Miers, Dipladenia acicularis K. Schum., D. gentianoides A. DC., D. gentianoides var. glabra Müll. Arg., D. gentianoides [var. velutina (Mart. ex Stadelm.) Müll. Arg.] subvar. longiloba Müll. Arg., D. illustris (Vell.) Müll. Arg. subf. hirsuta Müll. Arg., D. linariifolia A. DC., D. myriophyllum Taub. ex Ule, D. polymorpha Müll. Arg. subvar. glabra Müll. Arg., D. polymorpha var. intermedia Müll. Arg., D. tenuifolia (J. C. Mikan) A. DC. var. puberula A. DC., D. tenuifolia var. volubilis A. DC., D. tetradenia Rusby, D. vincaeflora Lem., Echites alexicacus Mart. ex Stadelm., E. illustris Vell., E. longiflorus Desf., E. maranhamensis G. Don, E. pastorum Mart. ex Stadelm., E. pohlianus Stadelm., E. pohlianus var. latifolius Stadelm., E. pubiflorus G. Don, E. pulchellus Gardner ex Hook., E. rosa-campestris Endl., E. rugosus Benth., E. spigeliiflorus Stadelm., E. tenuifolius J. C. Mikan, E. versicolor Stadelm., E. virescens A. St.-Hil., Macrosiphonia martii Müll. Arg., Macrosiphonia velame (A. St.-Hil.) Müll. Arg. var. goyazensis Müll. Arg., and Mandevilla barretoi Markgr. Eight second-step lectotypifications are completed for Echites coccineus Hook. & Arn., E. petreus A. St.-Hil., E. pinifolius A. St.- Hil., E. velame A. St.-Hil., Laseguea erecta (Vell.) Müll. Arg. subf. griseo-olivacea Müll. Arg., L. erecta var. glabrescens Müll. Arg., Macrosiphonia verticillata Müll. Arg. var. intermedia Müll. Arg., and Macrosiphonia verticillata var. peduncularis Müll. Arg. A neotype is designated for Amblyanthera versicolor (Stadelm.) Müll. Arg. var. olivacea Müll. Arg. Two new synonymies are proposed: Mandevilla barretoi Markgr. under M. tenuifolia (J. C. Mikan) Woodson, and M. bradei Markgr. under M. spigeliiflora (Stadelm.) Woodson. [ABSTRACT FROM AUTHOR]

Eurasian watermilfoil (Myriophyllum spicatum) is an invasive submersed macrophyte that has infested many waters in North America since its introduction. Eurasian watermilfoil has the ability to alter the structure and function of the ecosystems that it invades. Eurasian watermilfoil was first surveyed in the Clark Fork River, MT in 2008, alongside the native northern watermilfoil (Myriophyllum sibiricum). Three reservoirs (Cabinet Gorge, Noxon Rapids and Thompson Falls) on the lower Clark Fork River had entire lake surveys conducted using the point intercept method. Morphological data from these surveys showed that only Eurasian watermilfoil and northern watermilfoil were present during the time of the surveys in 2008. The results of the morphological identification were supported by molecular identification at three different laboratories. In 2015, a genetic survey of watermilfoil species was conducted on the Noxon Rapids Reservoir and found that hybrid watermilfoil (Myriophyllum spicatum × sibiricum) was present. This hybridization event poses a number of issues for aquatic plant management. Hybrid watermilfoil is much more difficult to identify morphologically than its parent types. The hybrid is also more invasive and may be differentially susceptible to some herbicides than the parental type Eurasian watermilfoil. [ABSTRACT FROM AUTHOR]

Invasive plants have caused significant negative ecological and economic impacts throughout the world. Parrot’s feather (Myriophyllum aquaticum) is an aquatic plant introduced from South America to South Africa, USA, Europe, New Zealand through the aquarium trade. It was recently brought to China where naturalized populations have become widespread. However, there is little information about the status, distribution, and the ecological and economic impacts of parrot’s feather which is critical to the Chinese government and environmental managers. We summarized introduction pathway, current distribution, and ecological impacts of parrot’s feather by field investigations and literature review. Our study could provide significant references for the management of non-native aquatic plants in China. [ABSTRACT FROM AUTHOR]

The distribution of microplastics as a potential environmental risk in aquatic systems had gained increasing attention in recent years. While numerous studies had focused on the impacts of microplastics on aquatic plants, the impacts on plant species cannot been considered in isolation. This study investigated the effects of relatively low concentrations of microplastics (0 mg/L, 0.05 mg/L, 0.25 mg/L, 1.25 mg/L, and 6 mg/L) on Myriophyllum sp. "Roraima" in co-cultivation with Microcystis aeruginosa (M. aeruginosa). Microscopic observations confirmed the adsorption of microplastic particles to the roots of Myriophyllum sp. "Roraima". The presence of cyanobacteria could mask and moderate the effects of microplastics, creating an integrated impact on plants. This integrated impact potentially made it challenging to isolate and attribute specific effects solely to microplastics. Additionally, the co-cultivation with M. aeruginosa had its own effect on the plants. Results revealed that the plant shoot elongation was not significantly altered under the treatment conditions; however, the photosynthetic pigments demonstrated different patterns between the emergent and submerged sections. The activities of antioxidant enzymes, Catalase (CAT) and Peroxidase (POD), were activated once microplastics were introduced, and Ascorbate peroxidase (APX) was significantly increased in high microplastics concentrations. The responses of Myriophyllum sp. "Roraima" to microplastics exposure differentiated from those observed in the absence of M. aeruginosa. [Display omitted] • Microplastics impact Myriophyllum sp. "Roraima" ontogeny when co-cultured with M. aeruginosa. • The rhizosphere adsorption of microplastics was observed in Myriophyllum sp. "Roraima". • M. aeruginosa masks & adjusts molecular H 2 O 2 rise from microplastics in Myriophyllum sp. "Roraima". • Microplastics further activated the antioxidant enzymes in the presence of M. aeruginosa. [ABSTRACT FROM AUTHOR]

• Phytobius vestitus is a biological control candidate for Myriophyllum aquaticum. • Phytobius vestitus responds to plant species based on olfactory cues. • Plant chemistry and phylogeny largely determine the host selection. • Phytobius vestitus is mostly attracted to olfactory cues emitted by M. aquaticum. • This research warrants further investment into the potential use of P. vestitus. Biological control programmes involve pre-release studies that include host range tests to predict likely negative effects on native species. Behavioural responses of potential biological control agents to olfactory signals emitted by target and non-target species provide information on the host-finding and selection behaviour for safer agent selection. The weevil Phytobius vestitus (Coleoptera: Curculionidae) was identified as a potential biological control agent for the sustainable management of the aquatic weed Myriophyllum aquaticum (Haloragaceae). Using olfactometer-based bioassays, we analysed the host-finding and host-selection behaviour of P. vestitus across a variety of plant species closely related to M. aquaticum using a glass olfactometer. We further analysed the volatile organic compounds emitted by the target and non-target plant species to explain the weevil's observed preferences. We demonstrated that P. vestitus was able to recognise and discriminate between eight closely related Haloragaceae plant species and was significantly more attracted to the olfactory cues emitted by the target plant, M. aquaticum , compared to the other plant species. This study provides a first important indication of the specificity of P. vestitus and shows the role of plant chemistry in host selection and the possibility of refining host range assessment for potential biological control agents. However, exhaustive risk assessment for possible release into targeted new environments still requires further investigations. [ABSTRACT FROM AUTHOR]

Submerged macrophytes, as one of the most important primary producers in shallow lakes and streams, have attracted significant research attention, with relevant studies showing dynamic evolution over the past three decades. Here, we investigated the trends and characteristics of 2,836 relevant articles published between 1991 and 2018 based on bibliometric analysis. Our geographic-based results indicated a scarcity of studies on submerged macrophytes in Africa, but strong international collaboration in this field, especially that between Denmark and China. The top two core journal sources (Hydrobiologia and Aquatic Botany) of studies on submerged macrophytes were determined, with another four important sources also identified. In addition, three trends in abstract word dynamics were found over the last three decades: i.e. most frequent word (‘lake’); increased words (those related to restoration, ecosystem state, model, and macrophyte community); and decreased words (those related to fish and specific macrophyte genera). Furthermore, our case study on four macrophyte genera showed a close relationship between Hydrilla and Vallisneria and between Potamogeton and Myriophyllum, as verified via the topic-article relationships determined using the topic model. The thematic evolution map of keywords used during the last three decades showed a clear shift in scientific fields; for example, Myriophyllum spicatum was an important keyword during 1999 and 2011 but not in other periods. We found that studies on submerged macrophytes developed with an increase in applied ecology topics, such as lake restoration, and basic scientific topics, such as freshwater ecosystems and plant physiology.

Phenotypic plasticity can determine the performance of exotic plants in environmental disturbance. Aquatic plants can adapt to the stress caused by water level fluctuations in the water level, water depth, or substrate nutrients through phenotypic plasticity. The high-potential invasiveness of Myriophyllum aquaticum in riparian wetlands may be associated with its growth and phenotypic plasticity. The interactive effects of fluctuations in the water level, water depth, and substrate nutrients on the growth performance of M. aquaticum were evaluated. We performed two two-factorial experiments to evaluate the effects of (i) frequency and amplitude of water level fluctuations and (ii) water depth and substrate nutrients on the performance of M. aquaticum. The results indicated that in the first experiment, low fluctuation frequency with a ± 20 cm amplitude significantly increased the value of all growth traits (except for total length of lateral branches). Regardless of fluctuation frequency, relative to a ± 60 cm amplitude and a static water level, the maximum values of total biomass, plant height, relative growth rate, and total length of lateral branches existed in moderate fluctuation amplitudes (± 20 cm, ± 40 cm). In the second experiment, the growth performance of M. aquaticum decreased with increasing water depth from 25 cm to 75 cm. High nutrient substrate significantly increased all growth traits (except for chlorophyll content) in water depths of 25 and 50 cm. Above all, M. aquaticum has optimal growth performance in response to low fluctuation frequency, moderate fluctuation amplitudes (± 20 cm, ± 40 cm), and high nutrient substrate in shallow water (water depth lower than 75 cm). These results indicate that M. aquaticum has a high-potential invasiveness in shallow water and with low disturbance of freshwater habitats. [ABSTRACT FROM AUTHOR]

The phytoremediation potential of Myriophyllum spicatum L. has been well documented for bulk-sized heavy metals, including zinc (Zn). However, there is no information on the removal efficiencies of this aquatic macrophyte for zinc oxide nanoparticles contaminated waters. Therefore, the present study was aimed to compare the removal efficiency of M. spicatum in two different media: tap water and pond water. Results were evaluated by comparing percentage (%) removal and goodness-of-fit to regression models. Plants were exposed to 0.8 and 2 ppm nano-sized Zn for 1, 4, and 7 days. The zinc concentrations were monitored using ICP-MS. The %removal in tap water ranged between 29.5 and 70.3%, and slightly higher in pond water. Modeling results confirmed that there was a strong relationship between removal performance and exposure duration. Time-dependent removal shows that %removal shows no further progress after 4 days. Our results also indicate that planktonic communities in pond water might play an important role in the fate of ZnO NPs. [ABSTRACT FROM AUTHOR]

This paper provides the results obtained after study of a small collection of benthic hydroids belonging to the superfamily Plumularioidea McCrady, 1859 collected during four oceanographic surveys, carried out between 2005 and 2008 along the Guinea Current Large Marine Ecosystem (GCLME) off the West African coast. The samples were obtained at nine stations located between 18 and 359 m depth using a bottom trawl (BT) and a Petersen grab. A total of 30 colonies were identified, belonging to 10 species, five genera and three families. The family Aglaopheniidae showed the highest specific richness, with five species, followed by Halopterididae (three species) and Plumulariidae (two species). One new species of the genus Aglaophenia Lamouroux, 1812, A. willasseni sp. nov., is described, and is characterized by the morphology of its lateral nematothecae, provided with two apertures, a feature described here for the first time within this genus. In addition, Halopteris alternata and H. diaphana are reported for the first time from the GCLME region. Our findings of Aglaophenia lophocarpa, Lytocarpia myriophyllum, H. alternata and H. diaphana in Gabon represent the southernmost records of these species in the eastern Atlantic. Publication LSID: lsid: [ABSTRACT FROM AUTHOR]

Microbes play an important role in the biotransformation of arsenic (As) speciation in various environments. Nevertheless, whether epiphytic bacteria that attached on submerged macrophytes have the potential to influence As speciation still remains unclear. In this study, sterile or nonsterile Myriophyllum verticillatum was cultured with arsenite (As(III)) or arsenate (As(V)) to investigate the impact of epiphytic bacterial community on As uptake, transformation, and efflux. Results showed that both sterile and nonsterile M. verticillatum did not display substantial As(III) oxidation, suggesting that neither M. verticillatum nor epiphytic bacterial community has the capacities of As(III) oxidation. However, sterile M. verticillatum exhibited capacity for As(V) reduction, and the presence of epiphytic bacterial community substantially enhanced the proportions of As(III) in the medium (from 39.91 to 98.44%), indicating that epiphytic bacterial community contributes significantly to As(V) reduction in the medium. The presence of epiphytic bacterial community elevated As accumulation (by up to 2.06-fold) in plants when exposed to As(V). Results also showed that epiphytic bacterial community contributed little to As(III) efflux. Quantitative PCR of As metabolism genes revealed the dominance of the respiratory As(V) reductase genes (arrA) in epiphytic bacterial community, which might play a significant role in As(V) reduction in aquatic environments. Phylogenetic analysis of the arrA genes revealed the widely distribution and diversity of As(V)-respiring bacteria. These results highlighted the substantial impact of the epiphytic bacterial community associated with submerged aquatic macrophytes on As biogeochemistry in wetland and water environments. [ABSTRACT FROM AUTHOR]

Submerged macrophytes have been found to be promising in removing cadmium (Cd) from aquatic ecosystems; however, the mechanism of Cd detoxification in these plants is still poorly understood. In the present study, Cd chemical forms and subcellular distributing behaviors in Myriophyllum aquaticum and the physiological mechanism underlying M. aquaticum in response to Cd stress were explored. During the study, M. aquaticum was grown in a hydroponic system and was treated under different concentrations of Cd (0, 0.01, 0.05, 0.25, and 1.25 mg/L) for 14 days. The differential centrifugation suggested that most Cd was split in the soluble fraction (57.40–66.25%) and bound to the cell wall (24.92–38.57%). Furthermore, Cd in M. aquaticum was primarily present in NaCl-extractable Cd (51.76–91.15% in leaves and 58.71–84.76% in stems), followed by acetic acid–extractable Cd (5.17–22.42% in leaves and 9.54–16.56% in stems) and HCl-extractable Cd (0.80–12.23% in leaves and 3.56–18.87% in stems). The malondialdehyde (MDA) and hydrogen peroxide (H2O2) concentrations in M. aquaticum were noticeably increased under each Cd concentration. The activities of catalase (CAT), guaiacol peroxidase (POD), and superoxide dismutase (SOD) in leaves were initially increased under relatively low concentrations of Cd but were decreased further with the increasing concentrations of Cd. The ascorbate (AsA), glutathione (GSH), and nitric oxide (NO) concentrations in stems increased with increasing Cd concentrations. Taken together, our results indicate that M. aquaticum can be used successfully for phytoremediation of Cd-contaminated water, and the detoxification mechanisms in M. aquaticum include enzymatic and non-enzymatic antioxidants, subcellular partitioning, and the formation of different chemical forms of Cd. [ABSTRACT FROM AUTHOR]

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• CW under 105 mg/L NH 4 +-N concs achieved optimal N removal efficiency. • Higher abundance of NarG and NosZ genes were found in high NH 4 +-N concs. CWs. • Denitrifiers including Rhodococcus.sp were enriched under high NH 4 +-N concs. CWs. • Increasing NH 4 +-N concs. led to enhanced interactions among microbial community. Constructed wetlands (CWs) have received increasing attentions for their N removal performances, especially regarding NH 4 +-N. Different influent NH 4 +-N concentration may influence N removal efficiency in practice, while the effects of different NH 4 +-N concentrations on microorganisms removing N in CWs are poorly understood. In this study, surface flow CWs planted with Myriophyllum (M). aquaticum were established to investigate the influences of different NH 4 +-N concentrations on the composition, structure, and interactions of microbial community. Our findings suggested 105 mg/L NH 4 +-N CWs achieved highest N removal rate, removing 89.30 % NH 4 +-N and 92.34 % TN from the influent. The results of real-time quantitative polymerase chain reactions (qPCR) indicated abundances of nitrifying genes (nxrA) and denitrifying genes (narG , nirS , nirK , and nosZ) were increased by increasing NH 4 +-N concentrations, and the strongest effects were observed in narG (8-fold) and nosZ genes (11-fold). Different NH 4 +-N concentrations was proved to alter composition and structure of microbial communities via high-throughput sequencing, e.g. denitrifiers including Brevendomonas.sp , Dokdonella.sp and Rhodococcus.sp were enriched obviously with increasing NH 4 +-N concentrations. In addition, network showed interactions among microbial populations and positive interactions were dramatically shifted and enhanced by increasing NH 4 +-N concentrations. [ABSTRACT FROM AUTHOR]

Water quality monitoring with integrative tools is a main issue of concern for environment assessment. Submerged aquatic macrophyte can be a good candidate for the evaluation of contaminant content in rivers. Indeed, owing to their habitat, aquatic macrophytes interact directly with surface water; they can absorb contaminants and thus allow to detect their presence in water. In situ studies were conducted over 28 days in five aquatic environments, affected by different levels of anthropogenic pressure (domestic wastewater plant, industrial activities), during two field campaigns. We have investigated whether the accumulation of some metals and a metalloid (As) in Myriophyllum alterniflorum could be used to detect their occurrence in river waters. Our results demonstrated that long time bioaccumulation was correlated with the contaminant levels in water. However, the water composition and the duration of exposure affected the studied pollutants' absorption. On an operational point of view, the optimal duration of exposure of Myriophyllum alterniflorum to assess the water quality is conditioned by the contaminant contents in waters that can induce different defense mechanisms as the reduction of pollutant absorption and their efflux. In addition, the nutrient concentration influenced the accumulation of pollutants since the higher the nutrient level, the higher the essential metal accumulation was observed. [ABSTRACT FROM AUTHOR]

Myriophyllum, among the most species‐rich genera of aquatic angiosperms with ca. 68 species, is an extensively distributed hydrophyte lineage in the cosmopolitan family Haloragaceae. The chloroplast (cp) genome is useful in the study of genetic evolution, phylogenetic analysis, and molecular dating of controversial taxa. Here, we sequenced and assembled the whole chloroplast genome of Myriophyllum spicatum L. and compared it to other species in the order Saxifragales. The complete chloroplast genome sequence of M. spicatum is 158,858 bp long and displays a quadripartite structure with two inverted repeats (IR) separating the large single copy (LSC) region from the small single copy (SSC) region. Based on sequence identification and the phylogenetic analysis, a 4‐kb phylogenetically informative inversion between trnE‐trnC in Myriophyllum was determined, and we have placed this inversion on a lineage specific to Myriophyllum and its close relatives. The divergence time estimation suggested that the trnE‐trnC inversion possibly occurred between the upper Cretaceous (72.54 MYA) and middle Eocene (47.28 MYA) before the divergence of Myriophyllum from its most recent common ancestor. The unique 4‐kb inversion might be caused by an occurrence of nonrandom recombination associated with climate changes around the K‐Pg boundary, making it interesting for future evolutionary investigations. [ABSTRACT FROM AUTHOR]

Myriophyllum aquaticum , renowned for its ability to purify aquaculture wastewater, faces a significant challenge due to its susceptibility to cold stress. However, the molecular mechanisms underlying M. aquaticum 's response to cold stress remain poorly understood. In this study, we unraveled the molecular mechanisms governing M. aquaticum 's response to cold stress through transcriptome sequencing and physiological analyses. Our investigation revealed 12,684 differentially expressed genes during cold stress. Gene ontology and KEGG analyses demonstrated the involvement of plant hormone signaling and transcriptional reprogramming related genes in M. aquaticum 's response to cold stress. Further investigations highlighted the role of jasmonic acid (JA) and abscisic acid (ABA) in M. aquaticum 's cold acclimation. Firstly, cold stress significantly increased endogenous levels of JA and ABA in M. aquaticum plants. Secondly, the transcript levels of several crucial JA and ABA signaling genes were prominently elevated, as shown by expression profiling and qRT-PCR analyses. Thirdly, the application of exogenous JA or ABA effectively mitigated foliar damage and improved cold tolerance in M. aquaticum plants. Furthermore, the expression of JA and ABA biosynthesis and signaling genes was significantly upregulated in JA- or ABA-pretreated plants when exposed to cold stress. Collectively, our findings provide evidence that JA and ABA contribute to the cold acclimation of M. aquaticum plants. Our research provides insights into the molecular mechanisms underlying cold acclimation of M. Aquaticum plants and presents a novel strategy to improve their cold tolerance, thereby expanding their potential application in phytoremediation efforts in high latitude areas. • Cold stress induces oxidative damage in M. aquaticum plants. • RNA-seq revealed plant hormone signaling and transcriptional reprogramming were upregulated. • Cold stress significantly increased endogenous levels of jasmonic acid and abscisic acid. • Cold response is associated with dynamic regulation of JA and ABA signaling genes. • Jasmonic acid and abscisic acid coordinately regulate cold acclimation in M. aquaticum. [ABSTRACT FROM AUTHOR]

Myriophyllum sibiricum and M. spicatum are sympatric in large part of their vast ranges in Eurasia and North America and have different habitat preferences only in East Europe and Siberia. Such absence of both geographic and ecological isolation should trigger extensive hybridization between these species that is indeed observed in North America. The hybrid could be reliably documented only with genetic markers, and in Eurasia this was done only in China. Using genetic markers (ITS2 region of nuclear ribosomal DNA and trn L -trn F intergenic spacer of cpDNA) we documented hybrids between M. sibiricum and M. spicatum on the North Asian Pacific islands with dynamic geological history and climate (Commander and the southern Kuril islands). The hybrid also originated in East Europe (Ivanovo Region) as a result of ecological isolation break due to rapid artificial habitat change. Using genetically verified material throughout temperate Eurasia we clarified morphological characters discriminating M. sibiricum and M. spicatum and, basing on them, refined the species distribution. For the first time we provide a full morphological characteristic of the hybrid between M. sibiricum and M. spicatum and suggest a name for it, M. × hybridum. • Hybrids between Myriophyllum sibiricum and M. spicatum were documented in Eurasia. • They were found on the North Asian Pacific islands and in East Europe. • We used genetic markers (nuclear ITS2 and plastid trn L -trn F) for documentation. • A name M. × hybridum was suggested for the hybrid. • Diagnostic characters for M. sibiricum and M. spicatum were clarified. [ABSTRACT FROM AUTHOR]