Juncus Effusus Research Articles

Corn Leaf Disease Classification Using Local Binary Patterns (LBP) Feature Extraction

Corn is a plant that is widely grown in developing countries such as Indonesia. To increase maize yields, researchers are always innovating on the current state of technology for classifying maize plant diseases. Three kinds of diseases attack corn leaves, namely Gray leaf Spot, Blight, and Common Rush. The amount of data that we use is 3500 data consisting of 500 Gray Leaf Spots, 1000 Blights, 1000 Common Rushes, and 1000 healthy leaves. This study aims to develop an artificial intelligence model. The artificial intelligence model that we developed uses LBP feature extraction combined with k-NN for the classifier. In addition to using the k-NN method, our tests were carried out using several classification methods such as Naïve Bayes and Adaboost. The result of our test is that the k-NN method has the highest value compared to the Naïve Bayes and Adaboost methods. The results of the performance using k-NN with k=5 resulted in a value of 81.1%, the AUC value of 94.1%, the F1-Score of 80.9%, Precision of 81.8%, and Recall of 81.1%.

Suppression of Phytophthora on Chamaecyparis in Sustainable Horticultural Substrates Depends on Fertilization and Is Linked to the Rhizobiome

Nature management residues (i.e., biomass generated from the management of nature reserves) are promising peat alternatives for horticultural substrates and may have a positive effect on disease suppression because of their microbiological characteristics. Moreover, addition of fertilizer may also affect the rhizosphere microbiome and, accordingly, disease suppression. In this study, we determined the effect of two management residues in horticultural substrates (i.e., chopped heath and acidified soft rush) and two fertilization regimes (i.e., pure nitrogen fertilizer and compound fertilizer) on the suppression of Phytophthora spp. on Chamaecyparis lawsoniana. The bacterial and fungal rhizosphere community was characterized using 16S ribosomal RNA and internal transcribed spacer 2 gene metabarcoding. Soft rush with a compound fertilizer (R2) and chopped heath with a pure nitrogen fertilizer (H1) showed a disease-suppressive effect and showed the largest shifts in microbial community composition compared with peat-based substrates. The disease-suppressive treatments showed differences in their microbial communities. Different genera associated with described biocontrol agents for Phytophthora spp. were found in higher amounts in those treatments. Aspergillus and Trichoderma spp. were highly abundant in H1, while Actinomadura and Bacillus spp. had a high abundance in R2. In addition, the relative abundances of 24 bacterial and 9 fungal genera were negatively correlated with disease severity. Several of those genera, including Bacillus, Chaetomium, and Actinomadura, were significantly more abundant in one of the disease-suppressive treatments. This study shows that disease suppressiveness in sustainable horticultural substrates is dependent on fertilization and can be linked to changes in the microbial rhizosphere communities.

Plant species contribution to bioretention performance under a temperate climate

Bioretention systems are green infrastructures increasingly used to manage urban stormwater runoff. Plants are an essential component of bioretention, improving water quality and reducing runoff volume and peak flows. However, there is little evidence on how this contribution varies between species, especially in temperate climates with seasonal variations and plant dormancy. The aim of our study was to compare the performance of four plant species for bioretention effectiveness during the growing and dormant periods in a mesocosm study. The species selected (Cornus sericea, Juncus effusus, Iris versicolor, Sesleria autumnalis) are commonly used in bioretention and cover a wide range of biological forms and functional traits.All bioretention mesocosms were effective in reducing water volume, flow and pollutant levels in both of the studied periods. Plants decreased runoff volume and increased contaminant retention by reducing water flow (up to 2.7 times compared to unplanted systems) and increasing water loss through evapotranspiration during the growing period (up to 2.5 times). Plants improved removal of macronutrients, with an average mass removal of 55 % for TN, 81 % for TP and 61 % for K compared to −6 % (release), 61 % and 22 % respectively for the unplanted systems. Except for Sesleria, mass removal of trace elements in planted mesocosms was generally higher than in unplanted ones (up to 8.7 %), regardless of season. Between-species differences in exfiltration rate and improved water quality followed the same order as their evapotranspiration rate and overall size, measured in terms of plant volume, leaf biomass, total leaf area and maximum average root density (Cornus > Juncus > Iris > Sesleria). By increasing evapotranspiration, plants decreased runoff volume and increased contaminant retention. Nutrient removal was partly explained by plant assimilation. Our study confirms the importance of plant species selection for improving water quality and reducing runoff volume during bioretention under a temperate climate.

Effects of Plant Growth–Promoting Rhizobacteria (PGPR) on the Phytoremediation of Pyrene-Nickel-Contaminated Soil by Juncus effusus

Effects of Plant Growth–Promoting Rhizobacteria (PGPR) on the Phytoremediation of Pyrene-Nickel-Contaminated Soil by Juncus effusus

Spatial characterization of microbial sulfur cycling in horizontal-flow constructed wetland models

Constructed wetlands (CWs) are a cost-effective technology for wastewater treatment in which plant-microorganism relationships play a key role in transforming pollutants. However, there is little knowledge about the spatial organization of microbial metabolic processes in CWs. Here we show the structuring of microbial transformation of inorganic sulfur compounds (ISCs) in two horizontal subsurface-flow CW models fed with sulfate-rich artificial wastewater. One model was fully planted with Juncus effusus, while the other was planted only in the middle to investigate further the influence of the plant on ISC transformations. Chemical analyses revealed that sulfate reduction and re-oxidation of sulfide/sulfur occurred simultaneously along the flow paths, with net reduction at the beginning of the CWs, where organic carbon from the influent was still present, and predominant re-oxidation in the downstream sections. Porewater ISC concentrations hardly differed between the two CWs. However, analysis of the bacterial communities showed that sulfur cycling in the fully planted CW was much higher. Total bacterial abundances were about 50 times and 3–4 orders of magnitude higher in the rhizoplane than in porewater and on gravel, respectively, as quantified by qPCR determination of the 16S rRNA gene. Sequencing of 16S rRNA gene amplicons revealed that bacterial communities on the roots and in the porewater differed substantially, apparently a consequence of the fluxes of oxygen and exudates from the roots. Furthermore, we observed partitioning of ISC transforming bacteria into different niches of the CWs. The results of the chemical and microbial analyses collectively support that extensive sulfur cycling occurred in the rhizospheres of the CW models. The study is relevant to the treatment of sulfur-containing wastewater and the elucidation of microbial communities involved in biogeochemical activities to improve water quality.

Functional ecosystem parameters: Soil respiration and diversity of mite (Acari, Mesostigmata) communities after disturbance in a Late Cambrian bedrock environment

AbstractWe analyzed the changes in ecosystem functions (soil respiration and Mesostigmata mite abundance, species richness and diversity) on various habitats after flooding by highly mineralized and acidic drainage water with fine As‐rich pyrite sediments, on a fragment of a natural ecosystem. In total, 177 plots that represented six types of habitats (undisturbed: pine mixed forests, Salix spp. thickets, Juncus effusus communities, wet meadows, and disturbed: bare ground and dead Salix spp. thickets) were sampled twice, in June 2019 and September 2020. Our study revealed that flooding affected essential ecosystem parameters, such as soil Mesostigmata mite abundance, species richness and diversity, and soil respiration, via an extreme decrease of soil pH. In total, 968 mites were collected from pooled data from the two samplings. Mite abundance, species richness and diversity were mainly shaped by habitat type and soil pH, and partially by soil respiration. These parameters were lower in disturbed habitats (bare ground and dead Salix spp. thickets) as compared with undisturbed ones. The highest mean mite density was recorded from mixed forests (4750 ± 600 ind. m−2) and wet meadows (2678 ± 361 ind. m−2), whereas the lowest in bare ground (449 ± 113 ind. m−2) and dead Salix spp. thickets (537 ± 146 ind. m−2). We noticed that mite diversity may be helpful to predict future changes in the physicochemical parameters of soils in disturbed areas. The vegetation patches built up by species adapted to grow in habitats characterized by relatively high metal and metalloid content (J. effusus and Salix spp.) represent an intermediate state of function of ecosystems in the study area.

Flexible and weavable 3D porous graphene/PPy/lignocellulose-based versatile fibrous wearables for thermal management and strain sensing

Fibrous wearable electronics have attracted extensive attention owing to their lightness and flexibility. However, they face challenges to work synergically with conductive components when stable performance and multifunction are required simultaneously. Here, plant-extracted 3D porous Juncus effusus (JE) fiber decorated with conductive graphene/polypyrrole (G-PPy) yields flexible smart fibers (G-PPy-JE) with integration of Joule heating and strain sensing properties. G-PPy-JE fibers were prepared by hierarchically anchoring the graphene sheets and PPy to 3D JE microfibrils via a facile dip coating and in-situ polymerization method. Synergistic effects in the hybrid architecture contribute to a highest conductivity of G-PPy-JE (96.85 S m−1) compared to pristine JE, G-JE, and PPy-JE. On the one hand, G-PPy-JE fibers showed a great electric-thermal property, which achieved a temperature of 147 °C at 10 V within 10 s. The good Joule heating performance maintained when weaving these fibers into fabrics as thermal therapy clothing. On the other hand, G-PPy-JE fibers after encapsulation can serve as a strain sensor with a high sensitivity (GF of 7.36–11.36), great stability (10–100 %), and good durability over 500 cycles. The strain sensor also reflected capabilities to detect a full range of human motions. This work paves a way for manufacturing cost-effective, green, and versatile fibrous electronics for promising wearable application.

Effects of Hydrologic Pulsing and Vegetation on Invertebrate Communities in Wetlands

Constructed, mitigation wetlands in the midwestern United States are frequently dominated by a Typha spp. monoculture and their hydrologies are often determined by adjustable control structures. Wetlands provide habitat for multiple macroinvertebrate species, which in turn provide food for other organisms inhabiting the wetlands, such as waterfowl. This study examined the impacts of plant diversity and manipulated hydrology on macroinvertebrate communities. Forty 1-m2 wetland mesocosms were either planted with a monoculture of Typha spp. or with a more diverse plant community of Schoenoplectus tabernaemontani, Juncus effusus, and Sparganium eurycarpum. They were also assigned to one of four hydrologic regimes: steady state, pulsing, deep spring/shallow fall, and shallow spring/deep summer. After one year, macroinvertebrates were sampled in the mesocosms. Mesocosms with deep spring hydrologies were found to have greater taxon diversity than those with other hydrologies, but Chironomidae biomass was the lowest under the deep spring hydrology. Culicidae and Chironomidae were found in higher numbers in mixed vegetation than in Typha spp. Taxon richness and Chironomid biomass were significantly higher in mixed vegetation mesocosms than in Typha spp. monocultures. Results suggest vegetation diversity and hydrological regimes impact macroinvertebrate communities, with potential implications for constructed wetland design and management.

Identification of sugars as root exudates of the macrophyte species Juncus effusus and Philodendron cordatum in constructed wetland-microbial fuel cells during bioelectricity production

ABSTRACT Constructed wetland-microbial fuel cells (CW-MFCs) systems are a sustainable technology capable of producing bioelectricity and treating wastewater simultaneously. It is also possible to obtain bioelectricity from the photosynthetic substrates obtained by the rhizodeposition of macrophytes, where the electroactive microorganisms present in the rhizosphere use these compounds as biofuel. In the present study, the bioelectricity production capacity of Juncus effusus and Philodendron cordatum species was evaluated in a CW-MFC without an external carbon source. The Juncus effusus species showed a higher bioelectrochemical performance, as they recorded a maximum voltage of 399 mV, a power density of 63.7 mW/m2, a volumetric power density of 15.9 W/m3, an internal resistance of 200 Ω, an anodic potential of -368 mV, and a cathodic potential of 229 mV. In addition, different types of carbohydrates in the form of sugars (sucrose, fructose, galactose, and glucose) were quantified by liquid chromatography, with concentrations of 100–450 μg/L. Chromatographic analysis were performed from the root exudates released in the effluent of both species of macrophyte. Sucrose and glucose were the types of sugars that produced the largest amount with portions of up to 35% and 24%, respectively. Sugars are compounds that worked as electron donors for the production of bioelectricity by using endogenous substrates that fed the anodic biofilm. Consumption was 45–55% for sucrose and 40–65% for glucose. Of the different macrophytes evaluated in the CW-MFCs, it was observed that the production of bioelectricity differs mainly due to the quantity of the root exudates released in the rhizosphere.

Succession of the Abandoned Rice Fields Restores the Riparian Forest.

The vegetation changes in the abandoned rice fields with different abandonment histories were analyzed across the country of South Korea. The successional process was confirmed by changes in vegetation profiles and species composition. The vegetation profile showed the process of starting with grassland, passing through the shrub stage, and turning into a tree-dominated forest. DCA ordination based on vegetation data showed that the process began with grasslands consisting of Persicaria thunbergii, Juncus effusus var. decipiens, Phalaris arundinacea, etc., then partially went through shrubland stages consisting of Salix gracilistyla, S. integra, young Salix koreensis, etc., and ultimately changed to a Salix koreensis dominated forest. In order to study the relationship between the succession process of the abandoned rice paddies and riparian vegetation, information on riparian vegetation was collected in the same watershed as the abandoned rice paddies investigated. Riparian vegetation tended to be distributed in the order of grasslands consisting of Phragmites japonica, Miscanthus sacchariflorus, P. arundinacea, etc., shrubland dominated by Salix gracilistyla, S. integra, etc., and a S. koreensis community dominated forest by reflecting the flooding regime as far away from the waterway. The result of stand ordination based on the riparian vegetation data also reflected the trend. From this result, we confirmed that the temporal sequence of the vegetation change that occurred in the abandoned rice fields resembled the spatial distribution of the riparian vegetation. Consequently, succession of the abandoned rice fields restored the riparian forest, which has almost disappeared in Korea and other Asian countries that use rice as their staple food.

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

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

Chromosome-scale genome assemblies and annotations for Poales species Carex cristatella, Carex scoparia, Juncus effusus, and Juncus inflexus.

The majority of sequenced genomes in the monocots are from species belonging to Poaceae, which include many commercially important crops. Here, we expand the number of sequenced genomes from the monocots to include the genomes of 4 related cyperids: Carex cristatella and Carex scoparia from Cyperaceae and Juncus effusus and Juncus inflexus from Juncaceae. The high-quality, chromosome-scale genome sequences from these 4 cyperids were assembled by combining whole-genome shotgun sequencing of Nanopore long reads, Illumina short reads, and Hi-C sequencing data. Some members of the Cyperaceae and Juncaceae are known to possess holocentric chromosomes. We examined the repeat landscapes in our sequenced genomes to search for potential repeats associated with centromeres. Several large satellite repeat families, comprising 3.2–9.5% of our sequenced genomes, showed dispersed distribution of large satellite repeat clusters across all Carex chromosomes, with few instances of these repeats clustering in the same chromosomal regions. In contrast, most large Juncus satellite repeats were clustered in a single location on each chromosome, with sporadic instances of large satellite repeats throughout the Juncus genomes. Recognizable transposable elements account for about 20% of each of the 4 genome assemblies, with the Carex genomes containing more DNA transposons than retrotransposons while the converse is true for the Juncus genomes. These genome sequences and annotations will facilitate better comparative analysis within monocots.

Repeat-based holocentromeres influence genome architecture and karyotype evolution

The centromere represents a single region in most eukaryotic chromosomes. However, several plant andanimal lineages assemble holocentromeres along the entire chromosome length. Here, we compare genome organization and evolution as a function of centromere type by assembling chromosome-scale holocentric genomes with repeat-based holocentromeres from three beak-sedge (Rhynchospora pubera, R.breviuscula, and R.tenuis) and their closest monocentric relative, Juncus effusus. We demonstrate that transition to holocentricity affected 3D genome architecture by redefining genomic compartments, while distributing centromere function to thousands of repeat-based centromere units genome-wide. We uncover a complex genome organization in R.pubera that hides its unexpected octoploidy and describe a marked reduction in chromosome number for R.tenuis, which has only two chromosomes. We show that chromosome fusions, facilitated by repeat-based holocentromeres, promoted karyotype evolution and diploidization. Our study thus sheds light on several important aspects of genome architecture and evolution influenced by centromere organization.

Efficient removal and detoxification of Cr(VI) by PEI-modified Juncus effuses with a natural 3D network structure

In the present study, a novel PEI-modified Juncus effuses (PEI-JE) adsorbent was prepared based on the natural 3D network structure of JE via a simple and environmental-friendly method with the help of the ethanol/aqueous solution. SEM, EDS, ATR-FTIR and XPS were performed to reveal the physical and chemical structure of the PEI-JE. The Cr(VI) removal by the PEI-JE was investigated by bath adsorption experiments. Results showed that the developed PEI-JE exhibited the same 3D network structure as the JE, which not only was easy to separate from aqueous solution but also can expose more active sites and facilitate mass transfer. The optimal pH for Cr(VI) adsorption on the PEI-JE was 3, and adsorption equilibrium time was related to initial Cr(VI) concentrations. The adsorption kinetic obeyed pseudo-second-order kinetic model, and the adsorption isotherm showed the best fit with Freundlich model. The calculated maximum adsorption capacity was 268.93 mg/g at 25℃. Coexisting ions including Na+, K+, Al3+, H2PO4−, Cl−, NO3– had no remarkable effect on Cr(VI) adsorption, but the presence of SO42−, HCO3– and CO32– caused the efficiency losses of 10.9%, 41% and 66%, respectively. After 10 cycles of adsorption/desorption, Cr(VI) removal rate on the PEI-JE almost kept unchanged, demonstrating that the PEI-JE possessed good reusability. Mechanism study suggested that Cr(VI) removal was involved in a three-step reaction, namely electrostatic adsorption, redox and complexation. Film diffusion was the rate-limiting step and chemical adsorption was the main mechanism. The Cr(VI) adsorbed on the PEI-JE surface was completely reduced to Cr(III), demonstrating that PEI-JE is useful for Cr (VI) removal and detoxification.

A Flexible and Weavable Lignocellulose-Based Photocatalyst Supported by Natural Three-Dimensional Porous Juncus effusus for Highly Efficient Degradation of Environmental Contaminants.

Lignocellulosic biomass is a potential biotemplate for disposing the burden of the uncontrollable accumulation of environmental contaminants disrupting the hydrophytic ecosystems. Herein, an efficient solar-driven catalyst was prepared using a natural three-dimensional (3D) porous lignocellulose-based Juncus effusus (JE) fiber for wastewater treatment. Owing to the exquisite 3D microstructure and abundant hydroxyl groups, the two-dimensional lamellar graphitic carbon nitride/graphene oxide (g-C3N4/GO) nanocomposites were successfully synthesized and decorated on the carboxymethylated JE fiber via the electrostatic self-assembly method. The as-prepared g-C3N4/GO-JE (CNG-JE) photocatalyst exhibits excellent light absorption efficiency and a superior ability to accelerate photogenerated electron migration. The outstanding adsorption performance toward pollutants also contributes to the photodegradation property of CNG-JE, showing highly efficient degradation of C.I. Reactive Red 120 (99.8%), C.I. Acid Yellow 11 (99.8%), methylene blue (99.4%), Cr(VI) (98.8%), and tetracycline (87.2%). Most importantly, the lignocellulose-based CNG-JE fibers could be fabricated into a photocatalyst textile due to their flexible and weavable properties. In actual application, the CNG-JE textile can be reused for at least five cycles under the sun, demonstrating that the flexible CNG-JE textile is practical and recyclable. This study may provide a platform for constructing efficient, flexible, and weavable biomass-based porous materials for cost-effective and sustainable catalytic applications.

Purification effect of aquatic plant communities in constructed wetland park: a comparative experiment of Tianhe wetland park in China

Constructed wetland parks in urban areas can offer the potential for integrating water conservation and purification. Compared with other treatments, filtering out pollutants by wetland plants is one of the methods used widely for its fast processing time and limited costs. And species allocation plays an important role in the purification process. However, some problems are still waiting for further discussions, such as the purification efficiency in winter due to plant growth rate, etc. Against this background, this paper introduced the Tianhe Wetland Park in China as the site for a comparative experiment, to propose a methodology for testing the purification effect under different plant communities. Through site investigation and lab experiments with water monitoring, the process of water purification by wetland was simulated in the park. After a period of observation and measurement, seven water indexes (pH value, dissolved oxygen, total phosphorus, total nitrogen, ammonia nitrogen, chemical oxygen demand, and turbidity) were selected for the evaluation of water quality to compare the different absorption efficiency by different communities. As a result, the research showed that a configuration of plant community using arboreal, emergent, and submerged plants can carry out a good purification effect during the winter, including Callistemon viminalis, Bischofia javanica, Canna indica, Juncus effusus, Vallisneria natans, and Hydrilla verticillata var. rosburghii. The removal rate of DO, TU, COD, TP, and TN by the designed community can reach 43%, 65%, 45%, 51%, and 62% in sampling sites. Finally, based on the research results, further suggestions for the development of wetlands were proposed to improve park management in the study area.

A flexible and sensitive strain sensor with three-dimensional reticular structure using biomass Juncus effusus for monitoring human motions

Flexible strain sensors have received extensive attention owing to their booming development. However, achieving high sensitivity and stretchability simultaneously for strain sensors is still a challenge. Herein, we report a fiber-based stretchable strain sensor with a unique three-dimensional (3D) reticular structure for human motion monitoring. The biomass Juncus effusus (JE) fiber was functionalized with carbon nanotubes (CNTs) and Ecoflex (EF) using a facile dip-coating-drying approach, and a syringe extraction method, respectively. The resulted JE/CNTs/EF fiber strain sensors exhibited advanced performance of strong flexibility, high sensitivity, and multifunctionality, which displayed a superior sensitivity (gauge factor of 24.95–76.79) and high stretchability (600%). Moreover, good repellency to chemicals and stable responses to various stimuli frequencies over 270 cycles were obtained for the as-prepared sensors. The microfibrils of the JE fiber formed a complicated 3D reticular structure acting as the conductive bridges when stretching. Consequently, the fiber-based JE/CNTs/EF strain sensor can not only accurately detect a full range of body motions and subtle signals, but also can be a promising candidate as a Morse code generator for cryptographic communication.

Plants inhibit the relative abundance of sulfonamide resistance genes and class 1 integron by influencing bacterial community in rhizosphere of constructed wetlands

Antibiotic resistance genes (ARGs) commonly detected in wastewater can potentially lead to a health crisis. Constructed wetlands (CWs) remove ARGs and sulfonamides (SAs) from wastewater, but the importance of plants in the process is seldom reported. We compared the effect of three wetland plant species (Cyperus alternifolius, Juncus effuses, and Cyperus papyrus), sample distance from the root, and SA presence on the environmental abundance of class 1 integron (intI1) and SA resistance genes (sul) using specially designed CW rhizoboxes. Quantitative polymerase chain reaction revealed that the relative abundance of the target genes in planted CWs, especially in C. alternifolius planted CWs, was significantly lower than that in unplanted CWs (P < 0.05). The substrate in the rhizosphere or near-/moderate-rhizosphere (closest to the root) showed the lowest average relative abundance of the target genes, while the bulk substrate (without the root) showed the highest abundance of these genes, irrespective of the planted species. Further, the influence of plants was more evident after 8 weeks of wastewater treatment. The trend was the same in SA-treated and untreated groups, although the relative abundance of the target genes was significantly higher in the former (P < 0.05). The weaker correlation between the intI1 and sul genes in the rhizosphere and near-/moderate-rhizosphere in comparison to the bulk substrate in the SA group suggested that the risk of horizontal gene transfer was probably higher in the bulk substrate and unplanted CW. A partial least-squares path model revealed that dissolved organic carbon and oxygen content significantly influenced SA concentration, microbial community, and intI1 genes, and then shaping the sul genes together. Finally, redundancy analysis suggested that abundance of sul genes was influenced by bacteria enriched in the bulk substrate and unplanted CWs. The findings provide new insights into the importance for controlling risk of ARGs by wetland plants.

Experimental Study on the Hydroponics of Wetland Plants for the Treatment of Acid Mine Drainage

Acid Mine Drainage (AMD) has become an important issue due to its significant ecological pollution. In this paper, phytoremediation technology and mechanism for AMD were investigated by hydroponic experiments, using six wetland plants (Phragmites australis, Typha orientalis, Cyperus glomeratus, Scirpus validus, Iris wilsonii, Juncus effusus) as research objects. The results showed that (1) the removal of sulfate from AMD was highest for Juncus effusus (66.78%) and Iris wilsonii (40.74%) and the removal of Mn from AMD was highest for Typha orientalis (&gt;99%) and Phragmites australis (&gt;99%). In addition, considering the growth condition of the plants, Juncus effusus, Iris wilsonii, and Phragmites australis were finally selected as the dominant plants for the treatment of AMD. (2) The removal pathway of pollutants in AMD included two aspects: one part was absorbed by plants, and the other part was removed through hydrolysis and precipitation processes. Our findings provide a theoretical reference for phytoremediation technology for AMD.

Physiological and Psychological Effects of Volatile Organic Compounds from Dried Common Rush (Juncus effusus L. var. decipiens Buchen.) on Humans.

This study compared the participants’ physiological responses and subjective evaluations of air scented with different concentrations of common rush (Juncus effusus L. var. decipiens Buchen.) (30 g and 15 g, with fresh air as a control). We asked 20 participants to complete a series of visual discrimination tasks while inhaling two different air samples. We evaluated (1) brain activity, (2) autonomic nervous activity, and (3) blood pressure and pulse rate, (4) in combination with self-evaluation. In addition, we quantified the concentrations of volatile organic compounds. The participants reported the scent to be sour, pungent, and smelly; this impression was likely caused by hexanal and acetic acid. Although the self-evaluations showed that participants did not enjoy the scent, their alpha amplitudes of electroencephalogram and parasympathetic nervous activity were increased, suggesting that participants were relaxed in this atmosphere. Moreover, a lower concentration resulted in a greater induction of relaxation. While the air was not pleasant-smelling, the volatile organic compounds present had a positive psychophysiological impact.