Greenhouse gases emissions and carbon budget estimation in horizontal subsurface flow constructed wetlands with different plant species.

Constructed wetlands (CWs) are pivotal for wastewater treatment due to their high efficiency and numerous advantages. The impact of plant species and diversity on greenhouse gas (GHG) emissions from CWs requires a more comprehensive evaluation. Moreover, controversial perspectives persist about whether CWs function as carbon sinks or sources. In this study, horizontal subsurface flow (HSSF) CWs vegetated with Cyperus alternifolius, Typhae latifolia, Acorus calamus, and the mixture of these three species were constructed to evaluate pollutant removal efficiencies and GHG emissions, and estimate carbon budgets. Polyculture CWs can stably remove COD (86.79 %), NH4+-N (97.41 %), NO3--N (98.55 %), and TP (98.48 %). They also mitigated global warming potential (GWP) by suppressing N2O emissions compared with monoculture CWs. The highest abundance of the Pseudogulbenkiania genus, crucial for denitrification, was observed in polyculture CWs, indicating that denitrification dominated in nitrogen removal. While the highest nosZ copy numbers were observed in CWs vegetated with Cyperus alternifolius, suggesting its facilitation of denitrification-related microbes. Selecting Cyperus alternifolius to increase species diversity is proposed for simultaneously maintaining the water purification capacity and reducing GHG emissions. Carbon budget estimations revealed that all four types of HSSF CWs were carbon sinks after six months of operation, with carbon accumulation capacity of 4.90 ± 1.50 (Cyperus alternifolius), 3.31 ± 2.01 (Typhae latifola), 1.78 ± 1.30 (Acorus calamus), and 2.12 ± 0.88 (polyculture) kg C/m2/yr. This study implies that under these operation conditions, CWs function as carbon sinks rather than sources, aligning with carbon peak and neutrality objectives and presenting significant potential for carbon reduction efforts.

Genome-Wide Identification and Expression Analysis of WNK Kinase Gene Family in Acorus.

WNK (With No Lysine) kinases are members of serine/threonine protein kinase family, which lack conserved a catalytic lysine (K) residue in protein kinase subdomain II and this residue is replaced by either asparagine, serine, or glycine residues. They are involved in various physiological regulations of flowering time, circadian rhythms, and abiotic stresses in plants. In this study, we identified the WNK gene family in two species of Acorus, and analyzed their phylogenetic relationship, physiochemical properties, subcellular localization, collinearity, and cis-elements. The results showed twenty-two WNKs in two Acorus (seven in Ac. gramineus and fifteen in Ac. calamus) have been identified and clustered into five main clades phylogenetically. Gene structure analysis showed all WNKs possessed essential STKc_WNK or PKc_like superfamily domains, and the gene structures and conserved motifs of the same clade were similar. All the WNKs harbored a large number of light response elements, plant hormone signaling elements, and stress resistance elements. Through a collinearity analysis, two and fourteen segmental duplicated gene pairs were identified in the Ac. gramineus and Ac. calamus, respectively. Moreover, we observed tissue-specificity of WNKs in Acorus using transcriptomic data, and their expressions in response to salt stress and cold stress were analyzed by qRT-PCR. The results showed WNKs are involved in the regulation of abiotic stresses. There were significant differences in the expression levels of most of the WNKs in the leaves and roots of Acorus under salt stress and cold stress, among which two members in Ac. gramineus (AgWNK3 and AgWNK4) and two members in Ac. calamus (AcWNK8 and AcWNK12) were most sensitive to stress. In summary, this paper will significantly contribute to the understanding of WNKs in monocots and thus provide a set up for functional genomics studies of WNK protein kinases.

Differential interference of copper with endophytic bacterial inoculation: Atrazine decontamination in Acorus tatarinowii and culture solution.

To clarify the interference effects of inorganic ions, Acorus tatarinowii and endophytic bacterium Herbaspirillum huttiense (Hh) were combined to decontaminate atrazine pollution under different copper levels. This study verified inoculation effects and revealed the complicated processes of atrazine transformation in solutions. 35.9% leaf biomass was promoted by Hh inoculation, and the value was lowered to 7.87% by high doses of copper. The changing trend of leaf N, K, and S contents, and tiller numbers were consistent with that of leaf biomass. Hh injection improved atrazine accumulation by 43.5% in roots, and under copper interference, this value lowered to 10.6%. Hh promoted atrazine deethylation in plants, which was copper-dose dependent in different plant organs. In solutions, atrazine was conjugated with small-molecule secretions at m/z 118, detoxicated into 2-hxydroatrazine and 2-hydroxy-4-acetamido-atrazine, then the triazine ring opened. Copper interference had a more significant impact on residual atrazine conversion products than Hh inoculation treatments. Hh treatment promoted the ring-opening degradation of atrazine in water. The addition of high doses of copper ions promoted the oxidative process of atrazine while inhibiting its ring-opening transformation process in water.

Herb pair of Polygala tenuifolia Willd and Acorus tatarinowii Schott decoction attenuates seizures and alleviates anxiety in mice: Evidence for modulating inflammation, alleviating oxidative stress and mediating GABA pathway.

Currently, prolong use of standard anti-epileptics may cause tolerance and ineffective for about 30% of epileptic patients. Medicinal plants provide an attractive therapeutic effect in preventing and treating seizures in traditional and folk medicine. In this study, we investigate the antiepileptic effects of PTAT decoction on acute and chronic seizure models in mice and explore the potential mechanisms. PTAT decoction dose-dependently protected mice against MES and PTZ induced seizure. Meanwhile, it decreased the seizure severity and reduced seizure-caused anxious behavior in the PTZ-kindling mice, suggesting a significant antiepileptic activity and anxiolytic/anxiogenic potential. PTAT decoction dose-dependently increased the levels of GSH and the activity SOD and CAT, while decreased the level of MDA in the hippocampi of treated mice. Furthermore, a significant decrease in the proinflammatory cytokine levels, including TNF-α, IL-1ß, IL-6 and MCP-1 was found in treated mice compared with the mice in the vehicle + PTZ group. Moreover, PTAT decoction dose-dependently reversed the alterations induced by PTZ in GABA, GABA-T, L-GAD and glutamate levels in kindling mice, showing an effect on the modulation of the GABA neurotransmission. Thus, PTAT decoction has a promising anticonvulsant activity mediated via multiple mechanisms, which might be used as an up-and-coming phytotherapy strategy in the management of epilepsy and its complications.

Hippocampal proteins discovery of Panax quinquefolius and Acorus gramineus ameliorating cognitive impairment in diabetic rats.

RATIONALE: Early diagnosis of diabetic cognitive impairment (DCI) and investigation of effective medicines are significant to prevent or delay the occurrence of irreversible dementia. OBJECTIVES: In this study, proteomics was applied to investigate the changes of hippocampal proteins after administration of Panax quinquefolius-Acorus gramineus (PQ-AG) to DCI rats, with a view to discover the differentially expressed proteins of PQ-AG action and elucidated the potential biological relationships. METHODS: The model and PQ-AG group rats were injected intraperitoneally with streptozotocin, and the PQ-AG group rats were continuously administered with PQ-AG. Social interaction and Morris water maze were performed to evaluate the behavior of rats on the 17th week after the model was established, and DCI rats were screened out from the model group by a screening approach. The hippocampal protein differences were investigated with proteomics in DCI and PQ-AG-treated rats. RESULTS: The learning and memory abilities and contact duration of DCI rats were improved after 16 weeks of PQ-AG administration. Altogether, 9 and 17 differentially expressed proteins were observed in control versus DCI rats and in DCI versus PQ-AG-treated rats, respectively. Three proteins were confirmed with western blotting analyses. These proteins were mainly involved in the pathways of JAK-STAT, apoptosis, PI3K/AKT, fork-head box protein O3, fructose, and mannose metabolism. CONCLUSIONS: This suggested that PQ-AG ameliorated cognitive impairment of diabetic rats by influencing the above pathways and providing an experimental basis for the mechanism of DCI and PQ-AG.

Acorus calamus recycled as an additional carbon source in a microbial fuel cell-constructed wetland for enhanced nitrogen removal.

Acorus calamus was recycled as an additional carbon source in microbial fuel cell-constructed wetlands (MFC-CWs), for efficient nitrogen removal of low carbon wastewater. The pretreatment methods, adding positions, and nitrogen transformations were investigated. Results indicated that alkali-pretreatment cleaved the benzene rings in dominant released organics, producing chemical oxygen demand of 164.5 mg from per gram of A. calamus. Pretreated biomass addition in the anode of MFC-CW attained the maximum total nitrogen removal of 97.6% and power generation of 12.5 mW/m2, which were higher than those with biomass in the cathode (97.6% and 1.6 mW/m2, respectively). However, the duration of a cycle with biomass in the cathode (20-25 days) was longer than that in the anode (10-15 days). Microbial metabolisms related to organics degradation, nitrification, denitrification, and anammox were intensified after biomass recycling. This study provides a promising method to improve nitrogen removal and energy recovery in MFC-CWs.

Asymmetric interaction and concurrent remediation of copper and atrazine by Acorus tatarinowii in an aquatic system.

To clarify the influence of organic pesticides on phytoremediation of potentially toxic metal elements, hydroponically-grown Acorus tatarinowii was used to repair copper pollution at six concentration levels with and without atrazine. Removal outcomes and processes exhibited asymmetry in an aquatic system. In plants, the addition of atrazine brought as much as 20.5% copper than control. Total amounts, percentage of protein or pectin combined copper and leaf: root ratio of copper were enhanced correspondingly. In solutions, cupric ions (Cu2+) were eliminated as much as 95.6% in plant remediation system. Though atrazine resulted in a quarter more absorption equilibrium concentration, the absorption reaction rate half declined. Copper removal in the system was contributed by both bound copper in solution and plant accumulation, and atrazine magnified contribution weight of the later one. Concurrent copper decreased absolute and relative amounts of atrazine in A. tatarinowii, indicating the influence of copper was mainly to reduce atrazine uptake by A. tatarinowii rather than to change the transformation of atrazine in plants. Copper exhibited antagonistic effects with atrazine in term of plant biomass, photosynthesis and oxidative-related responses (malondialdehyde, Ca, Fe and Mn), which might give support to asymmetry interaction between copper and atrazine accumulation in A. tatarinowii.

Exploring the biosynthetic pathway of lignin in Acorus tatarinowii Schott using de novo leaf and rhizome transcriptome analysis.

Acorus tatarinowii Schott is a well-known Chinese traditional herb. Lignin is the major biologically active ingredient and exerts a broad range of pharmacological effects: it is an antitumor, antioxidant and bacteriostatic agent, and protects the cardiovascular system. In the present study, the transcriptomes of the leaf and rhizome tissues of A. tatarinowii Schott were obtained using the BGISEQ-500 platform. A total of 141777 unigenes were successfully assembled, of which 76714 were annotated in public databases. Further analysis of the lignin biosynthesis pathway revealed a total of 107 unigenes encoding 8 key enzymes, which were involved in this pathway. Furthermore, the expression of the key genes involved in lignin synthesis in different tissues was identified by quantitative real-time PCR. Analysis of the differentially expressed genes (DEGs) showed that most of the up-regulated unigenes were enriched in rhizome tissues. In addition, 2426 unigenes were annotated to the transcriptome factor (TF) family. Moreover, 16 TFs regulating the same key enzyme (peroxidase) were involved in the lignin synthesis pathway. The alignment of peroxidase amino acid sequences and the analysis of the structural characteristics revealed that the key peroxidase enzyme had well-conserved sequences, spatial structures, and active sites. The present study is the first to provide comprehensive genetic information on A. tatarinowii Schott at the transcriptional level, and will facilitate our understanding of the lignin biosynthesis pathway.

Extraction and purification of cis/trans asarone from Acorus tatarinowii Schott: Accelerated solvent extraction and silver ion coordination high-speed counter-current chromatography.

Acorus tatarinowii Schott is a traditional Chinese medicine used to treat memory and cognitive dysfunction. Because of their efficacy and lower toxic effects, research on α- and ß-asarone, the phytoconstituents, has attracted attention owing to their remarkable pharmacological activities. Silver ion coordination complexation high-speed counter-current chromatography was used to separate these isomers from A. tatarinowii extract, coupled with accelerated solvent extraction. Accelerated solvent extraction parameters were investigated with single-factor and orthogonal testing. A two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water (2:1:2:1, v/v) with 0.50 mol/L silver ions was selected for separation. From 2.0 g crude extract, 1.4 g of ß-asarone and 0.09 g of α-asarone were obtained with purities over 98% by sequential sample loading in 20 h. The isolated compounds were identified by electrospray ionization mass spectrometry, 1H and 13C NMR. Silver ions significantly increased the separation factor and retention of the stationary phase. The chromatographic behavior indicated that cis-configuration was more strongly complexed with the silver ion. This was further demonstrated with the help of computational analysis. In conclusion, the established method could be employed to separate other cis-trans or E/Z isomers that form coordination complexes.

Neuroprotective Herbs for the Management of Alzheimer's Disease.

Background-Alzheimer's disease (AD) is a multifactorial, progressive, neurodegenerative disease that is characterized by memory loss, personality changes, and a decline in cognitive function. While the exact cause of AD is still unclear, recent studies point to lifestyle, diet, environmental, and genetic factors as contributors to disease progression. The pharmaceutical approaches developed to date do not alter disease progression. More than two hundred promising drug candidates have failed clinical trials in the past decade, suggesting that the disease and its causes may be highly complex. Medicinal plants and herbal remedies are now gaining more interest as complementary and alternative interventions and are a valuable source for developing drug candidates for AD. Indeed, several scientific studies have described the use of various medicinal plants and their principal phytochemicals for the treatment of AD. This article reviews a subset of herbs for their anti-inflammatory, antioxidant, and cognitive-enhancing effects. Methods-This article systematically reviews recent studies that have investigated the role of neuroprotective herbs and their bioactive compounds for dementia associated with Alzheimer's disease and pre-Alzheimer's disease. PubMed Central, Scopus, and Google Scholar databases of articles were collected, and abstracts were reviewed for relevance to the subject matter. Conclusions-Medicinal plants have great potential as part of an overall program in the prevention and treatment of cognitive decline associated with AD. It is hoped that these medicinal plants can be used in drug discovery programs for identifying safe and efficacious small molecules for AD.

Anti-Alzheimer's Disease Molecular Mechanism of Acori Tatarinowii Rhizoma Based on Network Pharmacology.

BACKGROUND Acori Tatarinowii Rhizoma (ATR), a traditional Chinese herbal medicine, is used to treat Alzheimer's disease (AD), which is a worldwide degenerative brain disease. The aim of this study was to identify the potential mechanism and molecular targets of ATR in AD by using network pharmacology. MATERIAL AND METHODS The potential targets of the active ingredients of ATR were predicted by PharmMapper, and the targets of Alzheimer's disease were searched by DisGeNET. All screened genes were intersected to obtain potential targets for the active ingredients of ATR. The protein-protein interaction network of possible targets was established by STRING, GO Enrichment, and KEGG pathway enrichment analyses using the Annotation of DAVID database. Next, Cytoscape was used to build the "components-targets-pathways" networks. Additionally, a "disease-component-gene-pathways" network was constructed and verified by molecular docking methods. In addition, the active constituents ß-asarone and ß-caryophyllene were used to detect Aß1₋42-mediated SH-SY5Y cells, and mRNA expression levels of APP, Tau, and core target genes were estimated by qRT-PCR. RESULTS The results showed that the active components of ATR participate in related biological processes such as cancer, inflammation, cellular metabolism, and metabolic pathways and are closely related to the 13 predictive targets: ESR1, PPARG, AR, CASP3, JAK2, MAPK14, MAP2K1, ABL1, PTPN1, NR3C1, MET, INSR, and PRKACA. The ATR active components of ß-caryophyllene significantly reduced the mRNA expression levels of APP, TAU, ESR1, PTPN1, and JAK2. CONCLUSIONS The targets and mechanism corresponding to the active ingredients of ATR were investigated systematically, and novel ideas and directions were provided to further study the mechanism of ATR in AD.

Essential Oil of Acorus tatarinowii Schott Ameliorates Aß-Induced Toxicity in Caenorhabditis elegans through an Autophagy Pathway.

BACKGROUND: Acorus tatarinowii Schott [Shi Chang Pu in Chinese (SCP)] is a traditional Chinese medicine frequently used in the clinical treatment of dementia, amnesia, epilepsy, and other mental disorders. Previous studies have shown the potential efficacy of SCP against Alzheimer's disease (AD). Nevertheless, the active constituents and the modes of action of SCP in AD treatment have not been fully elucidated. PURPOSE: The aim of this study was to investigate the protective effects of SCP on abnormal proteins and clarify its molecular mechanisms in the treatment of AD by using a Caenorhabditis elegans (C. elegans) model. METHODS: This study experimentally assessed the effect of SCP-Oil in CL4176 strains expressing human Aß in muscle cells and CL2355 strains expressing human Aß in pan-neurons. Western blotting, qRT-PCR, and fluorescence detection were performed to determine the oxidative stress and signaling pathways affected by SCP-Oil in nematodes. RESULTS: SCP-Oil could significantly reduce the deposition of misfolded Aß and polyQ proteins and improved serotonin sensitivity and olfactory learning skill in worms. The analysis of pharmacological action mechanism of SCP-Oil showed that its maintaining protein homeostasis is dependent on the autophagy pathway regulated partly by hsf-1 and sir-2.1 genes. CONCLUSION: Our results provide new insights to develop treatment strategy for AD by targeting autophagy, and SCP-Oil could be an alternative drug for anti-AD.

Nitrogen Metabolism in Acorus calamus L. Leaves Induced Changes in Response to Microcystin-LR at Environmentally Relevant Concentrations.

Acorus calamus L., a semiaquatic plant with a high capacity to remove nitrogen and phosphorus from polluted water, is a potential candidate plant for use in the restoration of eutrophic aquatic ecosystems. However, it is not clear how microcystins (MCs), commonly found in eutrophic water, influence plant growth since the effects of MCs are likely to be dose and species dependent. The present study aimed to investigate the regulation of nitrogen metabolism, a key metabolic process related to plant growth, in the leaves of A. calamus L. exposed to microcystin-leucine-arginine (MC-LR) (1.0-29.8 µg/L). Nitrate (NO3-) uptake, assimilation and transformation was stimulated in the leaves of A. calamus L. when exposed to 1.0 µg/L MC-LR through the elevation of nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT), glutamic-pyruvic transaminase (GPT), and glutamic-oxaloacetic transaminase (GOT) activity. Conversely, MC-LR inhibited nitrogen metabolism by decreasing NO3- uptake and the activities of enzymes related to nitrogen metabolism following exposure to MC-LR (9.9-29.8 µg/L) for 30 days, while, ammonium nitrogen (NH4+) content and glutamate dehydrogenase (GDH) activity increased significantly (p < 0.05, LSD test), when compared with the control group. Chronic exposure to MC-LR (9.9-29.8 µg/L) negatively influenced nitrogen metabolism in A. calamus L. leaves, which suggested that it may not be a suitable candidate species for use in the restoration of eutrophic aquatic ecosystems containing MC-LR at concentrations ≥ 9.9 µg/L.

Effects of antibiotics on nitrogen uptake of four wetland plant species grown under hydroponic culture.

To investigate the effects of antibiotics on nitrogen removal and uptake by wetland plants, four typical macrophyte species, Cyperus alternifolius L., Typha angustifolia L., Lythrum salicaria L., and Acorus calamus L., were grown in hydroponic cultivation systems and fed wastewater polluted with 10 µg L-1 Ofloxacin (OFL) and Tetracycline (TET). Biomass production, nitrogen mass concentration, chlorophyll content, root exudates, and nitrogen removal efficiency of hydroponic cultivation were investigated. The results indicated that in all hydroponic systems, NH4+-N was entirely removed from the hydroponic substrate within 1 day and plant nitrogen accumulation was the main role of the removed NO3-. OFL and TET stimulated the accumulation of biomass and nitrogen of A. calamus but significantly inhibited the NO3--N removal ability of L. salicaria (98.6 to 76.2%) and T. augustifolia (84.3 to 40.2%). This indicates that A. calamus may be a good choice for nitrogen uptake in wetlands contaminated with antibiotics. OFL and TET improved the concentrations of total organic carbon (TOC), total nitrogen (TN), organic acid, and soluble sugars in root exudates, especially for oxalic acid. Considering the significant correlation between TOC of root exudates and nitrogen removal efficiency, the TOC of root exudates may be an important index for choosing macrophytes to maintain nitrogen removal ability in wetlands contaminated with antibiotics.

Molecular cloning and functional characterization of an O-methyltransferase catalyzing 4'-O-methylation of resveratrol in Acorus calamus.

Resveratrol and its methyl ethers, which belong to a class of natural polyphenol stilbenes, play important roles as biologically active compounds in plant defense as well as in human health. Although the biosynthetic pathway of resveratrol has been fully elucidated, the characterization of resveratrol-specific O-methyltransferases remains elusive. In this study, we used RNA-seq analysis to identify a putative aromatic O-methyltransferase gene, AcOMT1, in Acorus calamus. Recombinant AcOMT1 expressed in Escherichia coli showed high 4'-O-methylation activity toward resveratrol and its derivative, isorhapontigenin. We purified a reaction product enzymatically formed from resveratrol by AcOMT1 and confirmed it as 4'-O-methylresveratrol (deoxyrhapontigenin). Resveratrol and isorhapontigenin were the most preferred substrates with apparent Km values of 1.8 µM and 4.2 µM, respectively. Recombinant AcOMT1 exhibited reduced activity toward other resveratrol derivatives, piceatannol, oxyresveratrol, and pinostilbene. In contrast, recombinant AcOMT1 exhibited no activity toward pterostilbene or pinosylvin. These results indicate that AcOMT1 showed high 4'-O-methylation activity toward stilbenes with non-methylated phloroglucinol rings.

Effects of lead stress on the growth, physiology, and cellular structure of privet seedlings.

In this study, we investigated the effects of different lead (Pb) concentrations (0, 200, 600, 1000, 1400 mg kg-1 soil) on the growth, ion enrichment in the tissues, photosynthetic and physiological characteristics, and cellular structures of privet seedlings. We observed that with the increase in the concentrations of Pb, the growth of privet seedlings was restricted, and the level of Pb ion increased in the roots, stem, and leaves of the seedlings; however, most of the ions were concentrated in the roots. Moreover, a decreasing trend was observed for chlorophyll a, chlorophyll b, total chlorophyll, net photosynthesis (Pn), transpiration rate (Tr), stomatal conductance (Gs), sub-stomatal CO2 concentration (Ci), maximal photochemical efficiency (Fv/Fm), photochemical quenching (qP), and quantum efficiency of photosystem II (ΦPSII). In contrast, the carotene levels, minimum fluorescence (F0), and non-photochemical quenching (qN) showed an increasing trend. Under Pb stress, the chloroplasts were swollen and deformed, and the thylakoid lamellae were gradually expanded, resulting in separation from the cell wall and eventual shrinkage of the nucleus. Using multiple linear regression analysis, we found that the content of Pb in the leaves exerted the maximum effect on the seedling growth. We observed that the decrease in photosynthetic activation energy, increase in pressure because of the excess activation energy, and decrease in the transpiration rate could result in maximum effect on the photosynthetic abilities of the seedlings under Pb stress. Our results should help in better understanding of the effects of heavy metals on plants and in assessing their potential for use in bioremediation.

Is it safe to use Acorus calamus as a source of promising bioactive compounds in prevention and treatment of cardiovascular diseases?

Acorus calamus has a rich history in natural medicine, and offers many health benefits. The plant has anti-inflammatory, antimicrobial, diuretic, antiurolithiatic and other properties. Moreover, various parts, especially the rhizome and roots, are sources of a range of bioactive phenolic compounds with beneficial effects on the cardiovascular system. This review article summarizes the current knowledge of the chemical composition of different parts of A. calamus and their roles in the prevention and treatment of cardiovascular diseases. However, as no human studies have been performed, the review only includes in vitro and animal studies. The paper also briefly reviews the toxicity of A. calamus and its products for human health, especially regarding the cardiovascular system.

Phytoremediation potential of Acorus calamus in soils co-contaminated with cadmium and polycyclic aromatic hydrocarbons.

Phytoremediation is a promising technology for the remediation of sites co-contaminated with inorganic (heavy metal) and organic pollutants. A greenhouse experiment was conducted to investigate the independent and interactive effects of cadmium (Cd) and polycyclic aromatic hydrocarbons (PAHs) on the growth of the wetland plant Acorus calamus and its ability to uptake, accumulate, and remove pollutants from soils. Our results showed that growth and biomass of A. calamus were significantly influenced by the interaction of Cd and PAHs after 60 days of growth. The combined treatment of low Cd and low PAHs increased plant biomass and Cd accumulation in plant tissues, thus enhancing Cd removal. Dissipation of PAHs from soils was not significantly influenced by Cd addition or by the presence of plants. Correlation analysis also indicated a positive relationship between residual concentrations of phenantherene and pyrene (PAHs), whereas enzyme activities (dehydrogenase and polyphenol oxidase) were negatively correlated with each other. Cluster analysis was used to evaluate the similarity between different treatments during phytoremediation of Cd and PAHs. Our results suggest that A. calamus might be useful for phytoremediation of co-contaminated soil.

Effectiveness of Vegetated Drainage Ditches for Domestic Sewage Effluent Mitigation.

Plant species have an important role in eco-ditches; however, the Michaelis-Menten kinetic parameters of nutrient uptake, growth rate and purification efficiency of ditch plants and their influences on domestic sewage treatment efficiency are still unclear. Growth rates of all nine species, but especially Lemna gibba, Cladophora and Myriophyllum verticillatum were best in undiluted domestic sewage as opposed to a mixture of domestic sewage. Performance of species to accumulate nutrients was not only species-specific, but was also affected by both sewage treatments. Removal efficiency of nutrients was dependent on both plant species and treatment. Uptake kinetic parameters were significantly affected by both nutrient form and plant species. The maximum uptake rate (Vmax) of NH4-N was higher than NO3-N. Similarly, Km values for NH4-N were greater than NO3-N. These results could be used to identify plants for sewage treatment efficiency and enhance water quality in eco-ditch treatment systems.

Phytoremediation of chlorpyrifos in aqueous system by riverine macrophyte, Acorus calamus: toxicity and removal rate.

The potential of Acorus calamus to remove chlorpyrifos from water was assessed under laboratory conditions. Toxic effects of the insecticide in A. calamus were evaluated using pulse-amplitude modulated chlorophyll fluorescence techniques as well. At exposure concentrations above 8 mg L(-1), A. calamus showed obvious phytotoxic symptom with significant reduction in quantum efficiency of PSII (ΦPSII) and photochemical quenching coefficient (qP) in 20-day test; the inhibition of maximal quantum efficiency of PSII (Fv/Fm) was accompanied by a significant rise in initial chlorophyll fluorescence (Fo) within 15-day exposures. Fv/Fm and Fo recover to the normal level after 20-day exposure. The reduced removal rate to chlorpyrifos was observed with increase of initial chlorpyrifos concentrations. At application levels of 1, 2, and 4 mg L(-1), the disappearance rate of chlorpyrifos in the hydroponic system with plants was significantly greater than that without plants during the 20-day test periods. Chlorpyrifos was taken up from medium and transferred to above ground tissues by the plant and significant amounts of chlorpyrifos accumulated in plant tissues. The result indicated that A. calamus can promote the disappearance of chlorpyrifos from water and may be used for phytoremediation of water contaminated with a relatively low concentration of chlorpyrifos insecticide (<4 mg L(-1)).