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As widespread wetland plants, Phragmites play a vital role in water purification and are widely utilized in constructed wetlands (accounting for 15.5% of applied wetland plants) as a natural alternative to wastewater treatment. However, despite such common applications, current understanding of the basic composition of the Phragmites root-inhabiting microbiome and the complex functions of each member of this microbiome remains incomplete, especially regarding pollution remediation. This review summarizes the advances that have been made in ecological and biochemical research on the Phragmites root microbiome, including bacteria, archaea, and fungi. Based on next-generation sequencing, microbial community compositions have been profiled under various environmental conditions. Furthermore, culture-based methods have helped to clarify the functions of the microbiome, such as metal iron stabilization, organic matter degradation, and nutrient element transformation. The unique community structure and functions are highly impacted by Phragmites lineages and environmental factors such as salinity. Based on the current understanding of the Phragmites root microbiome, we propose that synthetic microbial communities and iron-manganese plaque could be applied and intensified in constructed wetlands to help promote their water purification performance.

Penambangan Emas Tanpa Izin (PETI) merupakan penambangan emas yang dilakukan para penambang yang tidak memiliki izin. Salah satu dampak negatif PETI adalah pencemaran merkuri. Salah satu upaya memperbaiki tanah tercemar merkuri dapat dilakukan fitoremediasi. Tujuan penelitian untuk mengetahui tumbuhan lokal yang berpotensi mengurangi pencemaran merkuri (Hg). Penelitian menggunakan teknik purposive sampling dan dilakukan di Desa Monti, Sarolangun, Jambi. Inventarisasi tumbuhan memperoleh 14 spesies yaitu, Macaranga sp., Paspalum sp., Trema tomentosa, Imperata cylndrica, Lophatherum sp., Eleusine sp., Molineria sp., Lycopodium sp., Gleichenia linearis, Ipomea sp., Scleria sp., Eleocharis interstincta, Melastoma sp.., dan Phragmites sp. 14 tumbuhan tersebut, tiga yang mendominasi yaitu, Phragmites sp. (37,35%), Melastoma sp. (30,64%), dan Eleocharis interstincta (25,41%). Phragmites sp. memiliki nilai BAC (0,381), BCF (0,606), TF (0,628), Melastoma sp. memiliki nilai BAC (0,170), BCF (0,333), TF (0,511), dan Eleocharis interstincta memiliki nilai BAC (0,245), BCF (0,441), TF (0,555). Hasil perhitungan BAC, BCF dan TF didapatlah Phragmites sp. yang memiliki nilai paling tinggi sehingga kemampuan mengakumulasi dan mentranslokasi logam merkuri dari akar ke pucuk lebih efisien dibandingkan tumbuhan lain yang ditemukan pada penelitian ini.

Investigations of carbon dynamics of Eucalyptus and Phragmites feedstock’s made biochar amendments require laboratory soil incubations that provide controlled conditions. The aim was to evaluate the effects of two different biochar amendments on carbon mineralization potential of two different soils. Biochars were produced at 550 °C from the Eucalyptus and Phragmites feedstock materials and at 0, 10, 20, and 40 t ha−1 of doses were mixed with silty loam texture Balcali and clay texture, Kiziltapir soils. The soil + biochar amendments were incubated under constant temperature (28 °C) and moisture (80% of soil field capacity) conditions for 48 days. In both treatments, the biochar doses significantly increased CO2 emission After 48 days, both biochars increased cumulative carbon mineralization (Cmin) by more than 20% in Balcali soil (P

Phosphate is a critical pollutant leading to eutrophication in water bodies and significant adverse effect on water quality around the globe. The present study assessed the role of Phragmites-based constructed wetland (CW) towards the removal of phosphate from wastewater under natural environment and to assess the influence of meteorological parameters and seasonal changes. The Phragmites-based wetland removed phosphate with average efficiency of 80% at HRT of 24 h, and the removal efficiency increased with ambient temperature and amendment of ammonium in wastewater. Rhizospheric environment with slightly reducing conditions (Fe3+/Fe2+

The aim of this study was to evaluate long-term phosphorus (P) retention in a pilot-scale system made of four horizontal subsurface flow (HSSF) constructed wetlands for wastewater treatment. Each wetland had an area of 4.5 m2 and was operated for nearly 8 years (2833 days). Two wetlands with Schoenoplectus californicus (HSSF-Sch) and the other two with Phragmites australis (HSSF-Phr) were planted. The P removal efficiency was 18% for both types of HSSF wetlands. The primary factors that correlated with long-term P retention efficiency in HSSF were phosphorus loading rate (PLR), hydraulic loading rate (HLR) and dissolved oxygen (DO). Average biomass production of HSSF-Phr and HSSF-Sch was 4.8 and 12.1 kg dry weight (DW)/m2, respectively. The P uptake by the plant increased over the years of operation from 1.8 gP/m2 to 7.1 gP/m2 for Phragmites and from 3.2 to 7.4 gP/m2 for Schoenoplectus over the same periods. Moreover, the warm season (S/Sm) was more efficient reaching 14% P uptake than the cold season (F/W) with 9%. These results suggest that both plants' P retention capacity in HSSF systems represents a sustainable treatment in the long term.Novelty statement Long-term (8 years) phosphorus uptake by Schoenoplectus californicus and Phragmites australis and retention in pilot-scale constructed wetlands are evaluated. Schoenoplectus californicus is an uncommon species that has been less studied for phosphorus uptake compared to Phragmites australis, a globally known species in constructed wetlands. Moreover, some studies evaluating the performance of constructed wetland systems for domestic wastewater treatment are usually limited in time (1-3 years). Therefore, this long-term study demonstrates that the plant plays an important role in phosphorus retention, especially the species Schoenoplectus californicus. So, the phosphorus uptake by plants can contribute between 9 and 14% of the phosphorus load of constructed wetland systems in early years of operation.

Maintaining efficient and stable nitrogen (N) removal in constructed wetlands (CWs) that experience disturbance from their influent pollutant variations is crucial. The ammonium/nitrate (NH4+/NO3−) ratio of influent in CWs often varies widely. The N removal and stability in floating CWs have been found to be enhanced by manipulating plant species diversity. However, whether the positive effects occur in sand-based CWs remains unknown. Here, we established sand-based and hydroponic microcosms to investigate the differences in the responses of N removal and stability to plant species diversity under the disturbance of increasing influent NH4+/NO3− ratio in late period of plant growth. Results indicated that, (1) increasing plant species richness enhanced N removal but did not affect N removal stability in sand-based CWs under disturbance; (2) sand-based CWs had 46% higher average N removal stability than floating CWs, but the stability in floating CWs reached that in sand-based CWs at higher species richness levels; (3) under disturbed conditions, floating CWs with Phragmites australis or Typha latifolia achieved N removal and stability equivalent to those in sand-based CWs. This study indicates that, when treating wastewater with a variable NH4+/NO3− ratio, floating CWs with high plant species richness and specific species can achieve a win-win situation for high and stable N removal and bioenergy production.

The lipid and polysaccharide compositions of the plant Phragmites communis Trin. (Poaceae, Gramineae, grasses) growing in Uzbekistan were studied. The aerial part of the plant was found to contain more total lipids than inflorescences and roots. Lipids of the studied organs included 17–20 fatty acids with palmitic and total oleic and linoleic acids dominating. Water- and base-soluble polysaccharides were isolated from the aerial and subterranean organs of P. communis and characterized.

This study investigates the impact of wastewater irrigation on soil–plant–water system at the vegetative, flowering, and reproductive stages of Phragmites australis for two and four days (in each stage) in the coastal saline area of Urmia Lake. The concentrations of potentially toxic elements were detected in irrigated water, soil, and plant (aboveground and belowground) tissues, and transfer factor and bioaccumulation factor were calculated. The shoot biomass was significantly increased with increasing wastewater exposure, up to four days after the flowering stage. All potentially toxic elements concentrations in belowground (roots and rhizomes) tissues were higher than aboveground (leaves and stems) tissues. Fe showed the maximum concentrations in all organs at different growth stages due to the higher level contents in soil and water. Fe was found to be the least mobile at the reproductive stage and presented in the following order: roots > rhizomes > leaves ≥ stems. By contrast, Zn and Cd metals which are quickly transported in plants exhibited the same trend. Pb was accumulated at the flowering stage as follows: rhizomes > roots > stems > leaves. The toxic threshold was exceeded by Zn, Fe, Cu, and Cd in roots; Fe in rhizomes, and leaves; Cd in rhizomes; and Ni in roots. There was more efficiency in the removal of chemical oxygen demand (61.09%), biochemical oxygen demand (73%), total suspended solids (50%), and ammoniacal nitrogen (59.5%) at the reproductive stage. Therefore, P. australis could be an efficient and valuable tool for the phytoextraction and phytostabilization of metals if harvested at the proper time of growth in high potentially toxic elements polluted coastal ecosystems.

Riparian vegetation is constantly subjected to environmental stresses and reactive oxygen species (ROS) are generated in the plant tissue due to the stress. The study assessed the environmental stress in vegetation by quantifying the foliar hydrogen peroxide (H2O2) concentration across the elevation gradient of riparian zone of Hii River in Japan. Leaf samples of four common riparian species, Phragmites australis, Phragmites karka, Juglans mandshurica, and Salix pierotii, were used for the investigation. Leaf samples were collected at different elevations along the river. The results indicated that foliar H2O2 concentrations of P. australis, P. karka, and S. pierotii decrease with lower elevations indicating low levels of stress due to higher availability of soil moisture. However, J. mandshurica showed the opposite trend. This tree species had a higher concentration of foliar H2O2 at lower elevations. J. mandshurica had a higher hydrogen peroxide content with decreasing soil nitrogen concentration, indicating that J. mandshurica prefer fertile soil, especially with regard to the nitrogen content. The results clearly indicate that for J. mandshurica, the preferential location and stress was mainly based on soil nutrient availability. Our findings reveal that hydrogen peroxide is a very efficient and reliable index for quantifying environmental stress for vegetation management.

Chlorophyll content can effectively reflect the health (growth condition) of vegetation. At present, chlorophyll retrieval is mostly based on pure species and traditional spectral indices but seldom considers the influence of canopy structural differences caused by interspecific competition of mixed vegetation on the accuracy of chlorophyll retrieval. Therefore, in this research, the native species Phragmites australis and invasive species Spartina alterniflora in the wetland of the Yangtze River Estuary were studied, and the mixed growth of the two species in the field was simulated accurately by setting different competition ratios. The differences in canopy spectral characteristics caused by different competition ratios and the effect of interspecific competition on the retrieval accuracy of canopy chlorophyll content (CCC) were analyzed. It is found that different competition ratios will lead to different spectral characteristics of the vegetation canopy, but these differences poorly reflect the spectral dimension. To solve this problem, the Hilbert-Huang transform (HHT) theory is introduced to decompose the spectrum and obtain frequency domain information, which is combined with spectral information to research the spectral response characteristics and retrieval of CCC under different interspecific competition ratios. Finally, the necessity of considering interspecific competition under mixed growth is analyzed by using the PROSAIL-D model from remote sensing. The results show that (1) the retrieval accuracy of CCC based on pure spectral indices is lower than that based on the mixed indices under different competition ratios, especially under the competition ratio of P:S = 1:1, and the R2 of the pure spectral index model is 0.714, but the R2 of the model increases to 0.803 after the HHT indices are added, with the accuracy of the retrieval model with the mixed index being the highest, with R2 and RMSE values of 0.874 and 17.378 µg.cm-2, respectively. (2) There are differences in the distribution of spectral index values under different competition ratios based on the remote sensing mechanism results of simulation data from the PROSAIL-D model, especially under mixed growth of Phragmites australis and Spartina alterniflora. (3) The HHT indices ESP1 and ESP2 are more sensitive to changes in the competition ratio under different competition conditions, showing a greater range of values. All the above results indicate that the frequency domain indices can reflect the change in canopy structure of mixed vegetation more accurately, and it is necessary to consider the level of interspecific competition in the retrieval of CCC from mixed vegetation.

The recently identified nosZII gene plays a key role in mitigating nitrous oxide (N2O) emissions, and emergent macrophytes along lakeshores are areas of significant N2O emissions. The rhizosphere microenvironments of emergent macrophytes provide habitats that can potentially influence the abundance and composition of nosZII-containing microorganisms and, therefore, N2O emissions. Here we compared the N2O/(N2O+N2) ratio between the rhizospheres of Phragmites australis and bulk sediments from lakes situated in the middle and lower reaches of the Yangtze River plain (YR) and Yunnan-Kweichow plateau (YK) in China. The abundance and composition of nosZII-containing members were investigated using the real-time quantitative PCR and high-throughput sequencing techniques. We also investigated the effects of sediment properties and denitrifying microbial communities on the N2O/(N2O+N2) ratio through path analysis. The rhizospheres of Phragmites australis maintained significantly higher potential denitrification rates, higher denitrifier abundance, and higher diversity of N2O-reducing microbial community, but lower N2O/(N2O+N2) ratio at the YR site (P < 0.05). The N2O/(N2O+N2) ratio at the YR site was mainly influenced by N nutrients and the abundance of nirK, nirS, and nosZII genes, whereas the sediment organic matter, and the abundance of nirK, nirS, and nosZI genes were strong predictors of the N2O/(N2O+N2) ratio at the YK site. This study revealed variable effects of Phragmites australis on altering the nosZII community composition and mitigating N2O emissions between different regions, which would provide useful information for reducing N2O emissions from the aquatic ecosystem.

Herbivore identity and intensity are important in mediating plant defense responses, but the effects of their interaction on the plant metabolome have not yet been fully explored. Here, gas chromatography mass spectrometry was utilized to detect the metabolic changes in leaves, stems and roots of the common reed Phragmites australis infested with different intensity combinations of leaf-chewing Laelia coenosa and stem piercing-sucking Dimorphopterus pallipes. The supervised partial least squares-discriminant analysis showed that feeding by the two insects distinctly changed the metabolic profiles of all plant tissues. Furthermore, different intensities of the two herbivores resulted in significantly different metabolites in leaves. Only a high intensity of D. pallipes activated a distinct metabolic profile in roots, whereas there was no difference in stem metabolites in response to different herbivore intensities. Significant combined feeding effects of the two herbivores on plant metabolic composition was only detected in leaves infested with high herbivore intensity. Generally, D. pallipes feeding had a stronger effect on metabolite contents in different tissues compared to L. coenosa feeding. There was mostly a linear relationship between responses of leaf metabolites and herbivore intensity, whereas root metabolites generally showed non-linear responses to herbivore intensity. Additionally, there were significant interactions during simultaneous feeding of the two herbivores in leaves, which tended to be antagonistic. In general, our study suggested that plant responses to herbivory vary among tissues and are affected differently based on herbivore identity and intensity, which may vary in their interactions on plant metabolites at the whole-plant level.

PREMISE Biological invasions increasingly threaten native biodiversity and ecosystem services. One notable example is the common reed, Phragmites australis, which aggressively invades North American salt marshes. Elevated atmospheric CO2 and nitrogen pollution enhance its growth and facilitate invasion because P. australis responds more strongly to these enrichments than do native species. We investigated how modifications to stomatal features contribute to strong photosynthetic responses to CO2 and nitrogen enrichment in P. australis by evaluating stomatal shifts under experimental conditions and relating them to maximal stomatal conductance (gwmax ) and photosynthetic rates. METHODS Plants were grown in situ in open-top chambers under ambient and elevated atmospheric CO2 (eCO2 ) and porewater nitrogen (Nenr ) in a Chesapeake Bay tidal marsh. We measured light-saturated carbon assimilation rates (Asat ) and stomatal characteristics, from which we calculated gwmax and determined whether CO2 and Nenr altered the relationship between gwmax and Asat . RESULTS eCO2 and Nenr enhanced both gwmax and Asat , but to differing degrees; gwmax was more strongly influenced by Nenr through increases in stomatal density while Asat was more strongly stimulated by eCO2 . There was a positive relationship between gwmax and Asat that was not modified by eCO2 or Nenr , individually or in combination. CONCLUSIONS Changes in stomatal features co-occur with previously described responses of P. australis to eCO2 and Nenr . Complementary responses of stomatal length and density to these global change factors may facilitate greater stomatal conductance and carbon gain, contributing to the invasiveness of the introduced lineage.

Wetland eutrophication is a global ecological problem. Anaerobic oxidation of ammonium (ANAMMOX) and denitrification are the two major pathways of nitrogen removal in wetlands. However, little is known about the associated bacteria that are present around emergent macrophytes and their transcriptional activities. Here, we examine the transcriptional activity of bacteria that perform ANAMMOX and denitrification in the roots and vegetated sediments of three emergent macrophytes and in unvegetated sediment from a eutrophic wetland. Roots and vegetated sediments of three emergent macrophytes (Phragmites australis, Typha angustifolia, and Scirpus triqueter) and unvegetated sediment were collected from Wuliangsuhai wetland, China. The community structure and transcriptional activity of ANAMMOX and denitrifying bacteria were examined at the DNA and RNA levels. Additionally, the sediment physicochemical properties were determined. ANAMMOX (hzsB) and denitrifying bacteria (nirK, nirS, and nirSII) were detected in all sediments and roots at the DNA level. However, at the RNA level, root-associated ANAMMOX bacteria, including Candidatus Jettenia and Candidatus Brocadia, were detected only in the roots of P. australis. In contrast, nirK-carrying active denitrifiers, such as uncultured bacteria, Sinorhizobium, Rhizobiales, Mesorhizobium, Rhizobium, Devosia, and Bosea (all Rhizobiales), were detected in the roots of T. angustifolia and S. triqueter. The reduction of nitrogen concentration in the sediments of the vegetation zone was probably associated with active ANAMMOX bacteria and denitrifiers. Active root-associated ANAMMOX bacteria and nirK-type denitrifiers were influenced by plant species, and they likely contribute to nitrogen removal in eutrophic wetlands.

Two new alkaloids, phranisines A–B (1–2), along with two known compounds, N-p-Coumaroyl serotonin (3) and N-p-coumaroyl-tryptamine (4), were isolated from the roots of Phragmites australis. The structures of 1–4 were established on the basis of extensive spectroscopic. The absolute configuration of compounds 1–2 were identified through quantum-chemical electronic circular dichroism (ECD) calculation compared with their experimental CD. All the isolated compounds were tested for their cytotoxic activities against HeLa and MCF-7 human cancer cell lines, and compounds 2–4 showed moderate cytotoxic activities against HeLa cell lines with IC50 values ranging from 13.2 to 18.6 μM.

The microstructure of leaf epidermis, the localization, and content of syringyl (S) and guajacyl (G) monolignol in epidermal cells of Phragmites australis grown in water and moderate drought soil on the bank of the Venetian strait of the Dnipro River in Kiev (Ukraine) were studied with the electron microscopic method and laser confocal microscopy. The trichomes, guard cells of stomata, epidermal cells of vaulted zones over veins of adaxial and abaxial surface contained syringyl and guajacyl, the content of which depended on plant ecotype. We established that moisture soil influenced the leaf epidermis ultrastructure, on the change of monolignols content and S/G ratio in epidermis leaf of reed. The investigations show that trichomes and the cells of the vaulted zone in the leaf epidermis were the main accumulator of monolignols. The obtained results suggest that change of the microstructure of leaves, content of the monolignols, and S/G ratio in leaves contribute to the preservation of optimal water status of plants and can be considered as the signs of plant phenotypic plasticity and adaptive marker depending on the conditions of water supply.

Using reed (Phragmites australis (Cav.) Trin. ex Steud) as raw material, straw pulp was prepared by low alkali (less than 6%) pretreatment combined with mechanical grinding. The effects of pretreatment times and alkali dosages on pulp properties and pretreatment solution were investigated. The results demonstrated that alkali pretreatment affected FPI beating efficiency, and the beating energy consumption was lowest when pretreated with alkali dosage of 4%. With 5% NaOH pretreatment, the produced handsheets showed excellent properties that exceeded the requirements of food packaging paper and C-class corrugated paper. Moreover, low silicon content (≤1.12 g/L) in the pretreatment liquor had an almost negligible effect relative to alkali recovery. Therefore, this study is important for researchers and industrial representatives seeking to use reed straw as material for pulping.

Soil microorganisms can be altered by plant invasion into wetland ecosystems and comprise an important linkage between phosphorus (P) availability and soil carbon (C) chemistry; however, the intrinsic mechanisms of P and C transformation associated with microbial community and function are poorly understood in coastal wetland. In this study, we used a sequential fractionation method and 13C nuclear magnetic resonance (NMR) spectroscopy to capture the changes in soil P pools and C chemical composition with bare flats (BF), native Phragmites australis(PA), and invasive Spartina alterniflora(SA), respectively. The responses of the soil microbial community using phospholipid fatty acid (PLFA) profiling and function indicated by nine enzyme activities associated with C, nitrogen (N), and P cycles were also investigated. Compared to PA and BF, SA invasion significantly (P < 0.05) changed P pools and mainly increased the available P by 17.5 and 37.0%, respectively. The presence of the plants (SA and PA) significantly (P < 0.05) altered the soil C chemical composition mainly by affecting the aliphatic functional groups, resulting in a lower alkyl C/O-alkyl C ratio value. Compared to BF and SA, PA significantly (P < 0.05) increased arbuscular mycorrhizal fungi (AMF) abundance. Soil enzyme activity, especially for the P and C cycle enzymes, was also affected by plant species with the highest geometric mean enzyme and hydrolase activity for the PA zone. We also found that soil C compositions and P pools were associated with microbial community structure and enzyme activity, respectively. However, little interaction between C and P was found on either soil microbial composition or soil enzyme activity variation. Further, microbial community composition was tightly correlated with the soil P compared to soil C chemistry, while enzyme activity showed more response with soil C chemistry compared to soil P pool changes.

Invasive species negatively impact vegetation communities. Invasive European common reed [Phragmites australis (Cav.) Trin. ex Steud. ssp. australis] is rapidly spreading throughout North American wetlands. As such, the suppression of P. australis populations is a goal of many managers, as its removal should provide an opportunity to restore native vegetation communities. In Ontario, managers applied a glyphosate-based herbicide to more than 400 ha of P. australis in ecologically significant coastal marshes, representing the first time this tool was used over standing water to suppress an invasive species in Canada. Using a before–after–control–impact monitoring design, we evaluated the efficacy of glyphosate-based herbicide at removing P. australis along a water-depth gradient and assessed the recovery of the vegetation community for 2 yr after treatment in relation to reference conditions. We found that herbicide suppressed more than 99% of P. australis 1 yr after treatment and worked effectively along the entire water-depth gradient (10 to 48 cm). However, the post-treatment vegetation community remains distinctive from reference marsh 2 yr after treatment. In many plots where P. australis was removed, nonnative European frog-bit (Hydrocharis morsus-ranae L.) is now dominant, likely aided by high lake-water levels.

Biochar produced by pyrolysis of biomass under oxygen‐limited conditions has recently attracted increasing attention. To investigate the effects of feedstock and pyrolysis temperature on biochar characteristics, Phragmites australis straw and Spartina alterniflora straw were used to produce biochars at different temperatures from 300 to 500°C with an increment of 50°C. The biochars were characterized by their yields, ash contents, elemental compositions (i.e., carbon [C], hydrogen [H], oxygen [O], and nitrogen [N]), functional groups, dissolved organic carbon (DOC) contents, carbon sequestration potential, higher heating values (HHVs), and production costs. The results illustrated that pyrolysis temperature negatively affected biochar yields, H and O contents. In contrast, biochar produced at high temperature showed high ash contents, C contents, HHVs, and stronger aromaticity with low H/C and O/C ratios. In addition, S. alterniflora‐derived biochar (SB) contained higher ash content but lower C/H/N/O contents and HHVs than P. australis‐derived biochar (PB; p

Few relevant research attempts have been made to determine heavy metal resistance mechanisms of rhizomatous perennial plants. Thus, it is pertinent to investigate the physiological and biochemical changes in Phragmites australis under metal-stressed conditions to facilitate the development of strategies to enhance copper (Cu) tolerance. We measured parameters related to plant growth and development, metal translocation and physiological responses of P. australis subjected to Cu stress. In addition, the differentially expressed proteins (DEP) were evaluated using the isobaric tag for relative and absolute quantification (iTRAQ) system. A large amount of copper accumulates in the roots of P.australis, but the growth parameters were not sensitive to Cu. However, the high concentration of Cu reduced the content of chlorophyll a and chlorophyll b, and the expression of important photosynthesis proteins PsbD, PsbO and PsaA were all down-regulated, so photosynthesis was inhibited. In contrast, the content of ascorbic acid and proline both increased with the increase of copper stress. P.australis fixed a large amount of Cu in its roots, limiting the migration of Cu to other parts of the plant. Moreover, Cu stress can affect photosynthesis by inhibiting the activity of PSI, PSII and LHCII. In addition, P.australis synthesizes ascorbic acid through the D-mannose/L-galactose pathway, and synthesizes proline through the ornithine pathway. Ascorbic acid and proline can increase Cu tolerance and protect photosynthesis. These results provide a theoretical basis for understanding the tolerance and repair mechanisms of plants in response to heavy metal pollution.

The major factors controlling the soil methane (CH4) concentration and CH4 emissions of various plant (mainly wetland) species were identified. Five plant species (Oryza sativa, Zizania latifolia, Phragmites australis, Sesbania cannabina, and Bidens tripartita) were separately cultivated under the flooded soil conditions. The direct CH4 scavenging potential of B. tripartita roots was also measured in conjunction with in vitro CH4 scavenging experiments using H2O2 and several transition metal ions. CH4 emissions from the soil-cultivated plants did not depend on the maximum CH4 emission potential for each plant species but on the soil CH4 concentrations, which were positively correlated with the CH4 production potential of the soil and negatively correlated with soil Eh values. Bidens tripartita roots possessed the highest increasing soil Eh potential and a direct, immediate, and continuous CH4 scavenging potential via the Fenton reaction using a considerably high concentration of root apoplastic H2O2 and rhizosphere Fe2+. Bidens tripartita presented the highest soil Eh ascending potential. The in vitro experiments suggested the involvement of・OH/FeIVO2+ via the newly termed rhizosphere Fenton reaction as a strong destructive power for CH4. To our knowledge, this is the first report on direct CH4 scavenging by high H2O2-exuding plant roots.

Despite increasing recognition of the critical role of coastal wetlands in mitigating climate change, sea-level rise, and salinity increase, soil organic carbon (SOC) sequestration mechanisms in estuarine wetlands remain poorly understood. Here, we present new results on the source, decomposition, and storage of SOC in estuarine wetlands with four vegetation types, including single Phragmites australis (P, habitat I), a mixture of P. australis and Suaeda salsa (P + S, habitat II), single S. salsa (S, habitat III), and tidal flat (TF, habitat IV) across a salinity gradient. Values of δ13 C increased with depth in aerobic soil layers (0-40 cm) but slightly decreased in anaerobic soil layers (40-100 cm). The δ15 N was significantly enriched in soil organic matter at all depths than in the living plant tissues, indicating a preferential decomposition of 14 N-enriched organic components. Thus, the kinetic isotope fractionation during microbial degradation and the preferential substrate utilization are the dominant mechanisms in regulating isotopic compositions in aerobic and anaerobic conditions, respectively. Stable isotopic (δ13 C and δ15 N), elemental (C and N), and lignin composition (inherited (Ad/Al)s and C/V) were not completely consistent in reflecting the differences in SOC decomposition or accumulation among four vegetation types, possibly due to differences in litter inputs, root distributions, substrate quality, water-table level, salinity, and microbial community composition/activity. Organic C contents and storage decreased from upstream to downstream, likely due to primarily changes in autochthonous sources (e.g., decreased onsite plant biomass input) and allochthonous materials (e.g., decreased fluvially transported upland river inputs, and increased tidally induced marine algae and phytoplankton). Our results revealed that multiple indicators are essential to unravel the degree of SOC decomposition and accumulation, and a combination of C:N ratios, δ13 C, δ15 N, and lignin biomarker provides a robust approach to decipher the decomposition and source of sedimentary organic matter along the river-estuary-ocean continuum.

In this study, we investigated the modeling of chromium (Cr(VI)) removal using globally available plant biomass: Phragmites australis and Ziziphus spina-christi. Biosorption parameters were initial Cr(VI) concentration (50–800 mg L−1), contact time (1–180 min), adsorbent dose (0.25–2.0 g L−1), and pH (2–8) at agitation speed of 100 rpm. Based on the results of batch experiments and modeling, pseudo-second-order model was fitted to the experimental data where R2 = 0.99; besides, diffusion model played a significant role in the rate-determining step. Isotherm models were fitted in the order of Langmuir > Freundlich > Temkin models. Maximum adsorption capacities were recorded 21.32 mg g−1 and 15.55 mg g−1 for Phragmites australis and Ziziphus spina-christi, respectively. Insights into biosorption behavior were determined using Fourier-transform infrared spectra (FT-IR), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). SEM–EDX revealed the chromium presence and its accumulation on both biosorbents after the biosorption process. Cr(VI) biosorption mechanism is illustrated and can be related to electrostatic interactions, reduction and chelation/complexation with the functional groups of both adsorbents.

Fen plants cultivated on wet peatlands might be an environmentally friendly alternative biogas substrate to maize and grass grown on drained peatlands. This study demonstrates that if Typha latifolia, Phragmites australis, and Phalaris arundinacea were harvested in mid-June, then their specific biogas yields (SBY) reached values of up to 581 LN kg−1 volatile solids (VS), which is similar to the SBY of grass, but lower than the SBY, of 670 LN kg−1 VS, for maize. Mixtures with equal or more than 10% T. latifolia or 40% P. arundinacea (VS-base) exhibited a reduced SBY compared to 100% maize silage in a batch-test. From the composition of the substrates, it remains unclear why fen plants degraded that poorly. However, during the semi-continuous long-term experiment, this effect led to an accumulation of non-degraded material, which destabilized the degradation process at loading rates above 3 kg VS m−3 d−1. Destabilization became apparent with substantial increases in the viscosity of the fermenter content, enrichment of acids and a worsened methane formation. Our findings suggest that only small proportions of maize could be replaced by fen plants as substrate for biogas plants.

Phragmites australis, which is widely distributed throughout the world, is often used in the phytoremediation of acid mine drainage (AMD) due to its various mechanisms for survival under extremely harsh conditions. To explore the different responses of different aerial organs of P. australis to stress, soil and plant samples were collected from the AMD-polluted area of the Tongling mining area. The contents of manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), arsenic (As), cadmium (Cd), and lead (Pb) in the soil and the leaf blades, leaf sheaths, and stems of P. australis as well as the contents/activities of cysteine synthase (CSase), superoxide dismutase (SOD), peroxidase (POD), glutathione (GSH), malondialdehyde (MDA), and proline (Pro) in the organs were determined. Our results revealed that the leaf sheath had the highest potential to store metals of all the organs. The highest translocation factor (TF) for Fe was observed from the stems to the leaf sheaths. A higher bioconcentration factor (BCF) for Mn was found in the leaf blades and leaf sheaths, while higher BCFs for Cd and Zn were observed in the stems. The content/activity of enzymatic and non-enzymatic stress-resistance substances varied from organ to organ. In general, the leaf sheaths remained almost as or slightly less stress-resistant than the leaf blades. It can be concluded that different plant organs play different roles in stress resistance, and understanding the tolerance mechanism of leaf sheaths to metals is essential for the application of phytoremediation procedures.

Accumulation of essential/beneficial and non-essential chemical elements by submerged (Stuckenia pectinata (L.) Börner) and emergent (Phragmites australis (Cav.) Trin. ex Steud.) rooted macrophytes in three water bodies was studied as dependent on water salinity (specific conductivity) and main environmental factors (temperature, pH of water, growing period, element contents in water and sediments). Inductively coupled plasma optical emission spectrometry (ICP - OES) was used for the element detection in the plants, sediments, and water. Multivariate statistics redundancy analysis (RDA) showed that investigated factors together explained 37.8 - 44.7% and 29.9 - 42.6% of the essential/beneficial and non-essential elements variability, respectively, whereas salinity was one of the main factors determining the accumulation of a number of elements (Mg, S, Na, Li, Sr, Sb) by the macrophytes. A decrease in the essential element contents (K, P, N, Cu, Zn) was observed in both species of the macrophytes during the growing season. Environmental factors (salinity, growing period, and pH) were more significant than the element contents in water and the sediments for the essential/beneficial element accumulation by two species of the macrophytes. The element contents in the sediments to a greater extent determined non-essential element accumulation by P. australis than by S. pectinata. The study showed that the efficiency of using P. australis and S. pectinata for remediation of aquatic ecosystems contaminated by heavy metals should not decrease with a salinity increase.

This study compared soil organic carbon (SOC) in wetlands dominated by native and one invasive plant specie to better understand how short-term Spartina alterniflora colonization affected carbon circulation in the Yellow River Delta (YRD). Freshwater marsh dominated by Phragmites australis (FM) had the highest SOC, total nitrogen (TN), and water-extractable organic carbon (WEOC) contents, whereas SOC contents varied only slightly among salt marshes covered by Suaeda salsa (SM2), S. alterniflora (SM3) and bare flat (MD). Invasion by S. alterniflora substantially changed the molecular characteristics of SOC. The spectral characteristics of Fourier-transform infrared spectroscopy (FTIR) of humic acids (HAs) were similar from 4000 to 1800 cm−1 but differed greatly from 1800 to 1000 cm−1 among four wetlands. Pyrolysis-gas chromatography/mass spectrometry technology (Py-GC/MS) was used to characterize molecular fingerprints of HAs. Aliphatics (27.38%), lignin (16.64%), nitrogen-containing compounds (Nc) (16.16%), polysaccharides (16.93%), and phenol (13.42%) were dominant in FM, and aliphatics, alkyl, and Nc were primary in HAs from MD, SM2, and SM3. Lignin moieties were only found in HAs from FM and SM3, which accounted for about 16.64% and 1.6% of the total ion current, respectively. The absorption bands of the FTIR spectrum around 3340 and 1650 cm−1 in FM samples were much larger than those in the other three wetlands. However, the ratio of the peak areas at 1620 and 2930 cm−1 (R1620/2930) in SM3, was lower than that in MD and SM2, and it meant carbon in SM3 was less stable. Proportions of lignin and phenol moieties to total ion counts (TIC) in MD and SM2 were 3.3% and 3.4%, while these proportions in FM and SM were 30% and 7.5%, respectively. It showed S. alterniflora invasion into salt marsh would increase SOC contents and its stability, while it will inverse if freshwater marsh was supplanted by S. alterniflora in the YRD.

Introduction: Heavy metals that enter organisms can cause illness and disease. Chelation therapy is a solution that uses chelating agents to protect these organisms by high accumulation. Materials and methods: The objective of this study is to evaluate the capability of different roots extracts from reed or EDTA (as standard) to complexate iron using, ferrozine-ferrous reducing assay or Zn and Cu using the murexide-Zn or Cu reducing assay in vitro. Results: the results proved that the organic phase of the first extract and EDTA (standard chelator), have the strongest chelation activities with respective rates of 70% and 97% for iron, 55% and 56% for zinc and 47% and 88% for copper compared to the control groups considered to be 100% of the complexation. Finally, the HPLC analysis showed the presence of six organic acids, which are probably responsible for this effect. Conclusion: The hexane extract and EDTA (standard), have the strongest chelation activities. Keywords: Phragmites australis, Chelation, Heavy metals, Organic acids, Ferrozine, Murexide.

Distribution and level of 16 individual and total polycyclic aromatic hydrocarbons (∑PAHs) were assessed in soils, roots and above-ground tissues of reed (Phragmites australis) on monitoring plots in the city of Kamensk-Shakhtinskyi (Southern Russia, Rostov Region). The total concentration of the 16 PAHs in soil samples ranged between 499.0 to 7177.9 µg kg-1. Samples from the plot no. 4 had the highest PAHs concentrations of 7177.9 µg kg-1. The mean concentration of ∑16PAHs in plot no. 3 was noticeably higher than those in other monitoring sites for both root (363.0 µg kg-1) and above-ground tissues (239.8 µg kg-1). The distribution of PAHs ring size was in the order of 5-6˃4˃3˃2 in soil samples and HMW PAHs fractions represent 57.3% of the total PAHs. The concentrations of 3-4 ring PAHs were higher than HMW PAHs with 5–6 aromatic rings in all P. australis tissues. Diagnostic ratios of PAHs indicated that anthropogenic activities were probably major sources of PAHs. Accordingly, the maximum accumulation was found for phenanthrene among the 16 priority PAHs in the most of the soil and plants samples. More PAHs were accumulated in roots, as reflected by its higher mean concentration of PAHs in each plot. In addition, the BCF and TF values of LMW PAHs with 2- and 3-rings were higher than those of HMW PAHs. Taken together, our results indicated that there were an intensive accumulation of PAHs in the zone of industrial sewage tanks and sludge reservoirs as well as an obvious translocations of PAHs from the polluted soils to plant tissues, therefore, more attention is required to be paid to the PAH contamination in this area.

Emissions of greenhouse gases (GHGs) have greatly impacted the global warming by altering the composition of the atmosphere. The effect of biochar on GHG mitigation has been mainly studied in amended mineral soils and agricultural soils. However, the interactive effects of waterlogging and biochar application on GHG emissions, in coastal wetlands, are still poorly understood, which is important when considering the application of biochar at specific sites. We carried out a soil incubation experiment for 90 days at 25 °C to investigate the effects of two types of biochar (Phragmites communis and Spartina alterniflora) with different application rates (0%, 1%, 5%, and 10%) (w/w) on GHG emissions from soil at two different water levels (unwaterlogged and waterlogged soils). Furthermore, soil pH, organic carbon, nitrogen, and phosphorus contents were analyzed after incubation to gain insights into the underlying mechanisms of the biochar’s effects on CO2, CH4, and N2O evolution. Waterlogging significantly reduced the cumulative CO2 flux by 36.27%, had no effect on cumulative CH4 flux, and significantly increased cumulative N2O flux by 50.82%, and the corresponding global warming potential (GWP) significantly decreased by 29.72%. Biochar application reduced not only the cumulative CO2 flux, but also the cumulative CH4 absorption, which may shift soils from being CH4 sinks to sources. After biochar application, the cumulative N2O release increased from unwaterlogged soils but decreased in waterlogged soils. There was no significant difference between biochar type on GHG emissions, but differences were observed among different application rates. The GWP significantly decreased by 27.64–⁠69.39% and 36.11–87.34% after biochar application in the unwaterlogged and waterlogged soils, respectively. As a consequence, biochar application may significantly decrease GWP of soils due to the large reduction of CO2 release. These results suggest that biochar application is an effective way to reduce GWP in the Yellow River Delta Wetlands, especially when biochar is applied in waterlogged soils at high application rates.

Phragmites australis grows as a pioneer plant species in several mine and flotation tailings ponds distinguished by extremely high concentrations of metals. The main goals of this study were to estimate the effects of the specific concentrations and combinations of accumulated metals on the efficiency of antioxidative enzymes and plant oxidative status. This study is relevant to our understanding of the common reed exceptional capacity to endure extreme edaphic conditions. Metal concentrations were determined in the sediment, roots and leaves. Antioxidative enzymes activities, amounts of pigments and phenolics, total antioxidative capacity (TAC), lipid peroxidation level (LP) were analysed in plant organs. Effects of accumulated metals depended on their concentrations and their stoichiometry. Antioxidative enzymes and TAC in roots were significantly reduced, resulting in consequent increase in LP. Pb concentration in leaves did not significantly change enzymes activities, whereas toxic level of Cu impeded activity of catalaze and ascorbate peroxidase. The results indicate that in the conditions of high root metal contamination the mechanisms involved in their immobilization and detoxification cannot completely restrain their toxicity. Their effects on enzymes activities depend on the type of enzyme, metal concentrations, specific ratios and interactions.

Sludge-based activated carbon with doped Phragmites australis was prepared using an environment-friendly method to treat waterworks sludge (WS) and obtain an economical adsorbing material for tetracycline (TC) elimination. For the WS, P. australis was used as an additive to optimize the preparation of activated carbon. Optimum preparation conditions were as follows: activation temperature, 600 °C; ZnCl2 concentration, 3 mol/L; activation time, 50 min; impregnation ratio (weight of mix sample: weight of ZnCl2) of 1:2.5; and the mixed ratio of P. australis with WS, 40%. The obtained activated carbon owned well-developed Brunauer–Emmett–Teller surface area (949.90 m2/g). The acidic and basic functional groups were improved to 0.762 and 0.016 mmol/g, respectively. The pseudo-second-order kinetic and Freundlich isotherm equations were more suitable models to simulate adsorption with the maximum adsorption capacity of 153.4 mg/g. According to the thermodynamic parameters, the adsorption process was spontaneous and endothermic. Electrostatic interaction, hydrogen bonding formation, and ion complexation adsorption mechanisms were the mechanisms underlying the adsorption of TC.

Many constructed wetland systems are facing the problem of low dissolved oxygen (DO) and reduced nitrogen removal efficiency. In this study, an experimental constructed wetland system is designed and used to investigate the effect of biochar (rice husk biochar (RHB), coconut shell biochar (CSB), and wood biochar (WB) and earthworm on DO concentration, nitrogen transformation, and ammonia nitrogen removal. Specifically, effects of different biochar and earthworm on NH4+-N in wastewater, N content of Phragmites australis, NH4+-N and NO3--N content in substrates, microbial nitrification and denitrification potentials, and the DO concentration were investigated. Results show that the addition of biochar and earthworm increased the removal efficiency of NH4+-N from wastewater. The addition of RHB and WB significantly increased the concentration of DO by 21.4% and 25.7% (P < 0.05) respectively in the constructed wetland. The addition of earthworm significantly increased the DO concentration in the constructed wetland system by an average of 30.35% (P < 0.05).The N content of P. australis increased when biochar and earthworm were introduced into the constructed wetland system, with higher relative N content observed in the above-ground biomass. NO3--N content increased, but NH4+-N decreased in the substrate. Addition of both biochar and earthworm increased nitrification and denitrification potentials. However, no significant increase in denitrification potential was observed when only biochar was added. The removal efficiency of NH4+-N from wastewater is significantly positively correlated with the DO, nitrification, and denitrification potential, and nitrogen content of above-ground part of P. australis (P < 0.05). Results suggest that the DO concentration in constructed wetland systems could be improved by the addition of biochar and earthworm. These findings imply that both biochar and earthworm could be added into constructed wetlands to solve the low DO concentration and improve the removal efficiency of nitrogen.

The robust Taguchi method was used to optimize the preparation of activated carbon by microwave radiation from the agricultural waste Phragmites australis. The potential for removing endocrine disr...

High mercury (Hg) affects biochemical-physiological characteristics of plant leaves such as leaf chlorophyll, causing refractive discontinuity and modifications in leaf spectra. Furthermore, the hyperspectroscopy provides a potential tool for fast non-destructive estimation of leaf Hg. However, there are few studies that have investigated Hg for wetland plants via hyperspectral inversion. In this study, reeds (Phragmites australis) leaf Hg concentration and hyperspectra were measured under different soil Hg treatment. Hg-sensitive parameters were identified by basic spectral transformations and continuous wavelet transformation (CWT). Inversion models were developed using stepwise multiple linear regressions (SMLR), partial least square regression (PLSR), and random forest (RF) to estimate leaf Hg. The results indicated that CWT improved the correlation of hyperspectra and leaf Hg by 0.020–0.227, and R2 of the CWT-related model increased by 0.0557–0.2441. In addition, Hg-sensitive bands were predominant at 600–750 (visible region) and 1500–2300 nm (mid-infrared), and Hg might modify leaves spectra primarily by affecting chlorophyll and water contents. Of the studied models, SMLR using normalized transformation (NR) and CWT (NR-CWT-SMLR) model (R2 = 0.8594, RMSE = 0.0961) and RF using NR and CWT (NR-CWT-RF) model (R2 = 0.8560, RMSE = 0.1062) suited for leaf Hg inversion. For Hg content

Operation of the indicators for the reliable regional carbon dioxide content in atmosphere is the important factor for the computer simulation of climatic changes at the appropriate scale. A goal is the experimental study of the processes for carbon dioxide gas exchange (photosynthesis and respiration) of wetland vegetation for the forest-steppe zone in Ukraine under recent climatic changes in order to determine the quantitative indicators for the CO2 removal rate from the atmosphere by this vegetation. For this the CO2 Qubit Systems s151 (Canada) are used to measure СО2 in air end spectroradiometer FieldSpec® 3FR (USA). This system has got the respiratory flow-through camber, where the test plant is placed. The CO2 concentration changes in this chamber are measured by IR gas analyzer for the certain timespan. Data are processed by LabProInterface. The results obtained for the main wetland plants (Carex riparia and Phragmites australis ) during the spring-summer vegetative period show that the growth of their productivity (CO2 removal rate from atmosphere) takes place only under the environmental temperature of 18-22 о С. Also, it is certain that the positive indicator for these systems is their appreciably longer photosynthetic activity period as compared with the different ecosystems due to the cooling effect of soil moisture in their habitat. It should be taking into account when the measures for minimization of regional warming effects are implemented with the maximally contributing to the reclamation and revivification of the wetlands.

Hydroponic constructed wetlands are effective alternative technology for water and wastewater treatment. In the present research, Chenopodium album, Amaranthus cruentus, Phragmites australis and Bambusa vulgaris plants were used in hydroponic constructed wetland for phytoremediation of cesium, lead, nitrate and sodium from synthesized wastewater. During the treatment of wastewater containing CsCl and Pb(C2H3O2)4, 59.57 ± 2.12% cesium and 95.32 ± 1.32% lead were remediated by Amaranthus cruentus at a period of 14 days. Initial concentration of CsCl and Pb(C2H3O2)4 was 0.5 mg L−1. In wastewater containing 5 mg L−1 CsCl and 5 mg L−1 Pb(C2H3O2)4, Cs phytoremediation efficiency was 49.11 ± 3.78%. Simultaneously, 98.40 ± 0.05% Pb was removed in a period of 14 days. In mesocosm constructed wetland vegetated with Phragmites australis and Bambusa vulgaris, 46.28 ± 0.005% nitrate was taken up by Bambusa vulgaris and 35.80 ± 0.01% nitrate was removed by Phragmites australis from wastewater containing 1000 mg L−1 KNO3 and 2000 mg L−1 NaCl in a period of 14 days. In the case of desalination, sodium uptake efficiencies by Phragmites australis and Bambusa vulgaris were 16.73 ± 0.56% and 32.62 ± 2.56%, respectively. In all the experiments, cesium shoot accumulation was more than root, while lead accumulated in roots more than shoots. The results also show that hydroponic constructed wetlands vegetated with terrestrial and aquatic plants are promising technology for wastewater treatment.

The present study estimated the ability of four aquatic macrophytes (Eichhornia crassipes (Mart.) Solms, Ludwigia stolonifera (Guill. & Perr.) P.H. Raven, Echinochloa stagnina (Retz.) P. Beauv. and Phragmites australis (Cav.) Trin. ex Steud.) to accumulate Cd, Ni and Pb and their use for indicating and phytoremediating these metals in contaminated wetlands. Three sites at five locations in the Kitchener Drain in Gharbia and Kafr El-Sheikh Governorates (Egypt) were selected for plant, water and sediment sampling. The water in the Kitchener Drain was polluted with Cd, while Pb and Ni were far below the maximum level of Pb and Ni in the irrigation water. In comparison to the other species, P. australis accumulated the highest concentrations of Cd and Ni, while E. crassipes accumulated the highest concentration of Pb in its tissues. The four species had bioaccumulation factors (BAFs) greater than one, while their translocation factors (TFs) were less than 1 for most heavy metals, except Cd in the leaf and stem of E. stagnina and L. stolonifera, respectively, and Ni in the stem and leaf of E. stagnina. The BAF and TF results indicated that the studied species are suitable for phytostabilizing the studied heavy metals, except Ni in E. stagnina and Cd in L. stolonifera, which are suitable for phytoextracting these metals. Significant positive correlations were found between the investigated heavy metals in the water or sediment and the plant tissues. Their high BAFs, with significant proportional correlations, supported the potential of these species to serve as bioindicators and biomonitors of heavy metals in general and in the investigated metals specifically.

Vanadium (V) plays important roles in physio-ecological processes of marsh plants. To investigate the effects of spatial expansion between native invasive species (Phragmites australis, PA) and common native species (Cyperus malaccensis, CM) on temporal variations and bioaccumulation of V in coastal marshes of the Min River estuary, in situ filed sampling was conducted in PA marsh (PAM, before expansion), CM marsh (CMM, before expansion) and ecotonal marsh (EM, during expansion, marsh plants were denoted by PA' and CM') at different seasons by space-for-time substitution method. Results showed that, over all sampling seasons, the mean V contents in marsh soils ranged from 99.71 to 108.41 mg·kg-1 which exceeded its background value in soils of Fujian province (78.3 mg·kg-1). The V levels in soils differed among seasons or marshes. Higher V contents in soils of PAM, EM and CMM generally occurred in spring and winter. Over all sampling seasons, the V levels in profiles of EM were much higher than those of PAM and CMM. The temporal variation of V levels in soils of EM might rest with the alterations of soil pH, SOM and plant ecological traits during the spatial expansion. Although the V contents in PA, PA', CM' and CM differed among tissues, both the roots/stems (R/S) and roots/leaves (R/L) ratios were larger than 1 while the stems/leaves (S/L) ratios were less than 1, implying that the values in roots were much higher than those in other tissues. The V levels in tissues differed among species or seasons, which could be interpreted by the differences in ecological traits among plants and the competitive absorption for V by plants during the spatial expansion. Allocations of V in organs differed among seasons or species and roots were the main V stock of plant subsystems. This paper found that the V in soils of the Min River estuary existed enrichment process and the spatial expansion between PA and CM promoted its enrichment in soils and its bioaccumulation by plants.

The direct discharge of azo dyes and/or their metabolites into the environment may exert toxic, mutagenic, and carcinogenic effects on exposed fauna and flora. In this study, we analyzed the metabolites produced during the degradation of an azo dye namely Reactive Black 5 (RB5) in the bacterial augmented-floating treatment wetlands (FTWs), followed by the investigation of their underlying toxicity. To this end, a FTWs system was developed by using a common wetland plant Phragmites australis in the presence of three dye-degrading bacteria (Acinetobacter junii strain NT-15, Pseudomonas indoloxydans strain NT-38, and Rhodococcus sp. strain NT-39). We found that the FTW system effectively degraded RB5 into at least 20 different metabolites with the successful removal of color (95.5%) from the water. The fish toxicity assay revealed the non-toxic characteristics of the metabolites produced after dye degradation. Our study suggests that bacterially aided FTWs could be a suitable option for the successful degradation of azo dyes, and the results presented in this study may help improve the overall textile effluent clean-up processes.