Pontederia Cordata Research Articles

Pontederia cordata Pickerel Weed

This document provides an overview of the pickerel weed (Pontederia cordata), a native aquatic plant found in Florida and other parts of eastern North America. It describes the plant’s habitat, growth characteristics, and ornamental features, highlighting its adaptability to shallow wetland areas and its attractive purple-blue flowers. The document also covers planting guidelines, including optimal water depth and spacing, and notes the plant’s aggressive growth habit and potential for use in water gardens and pond stabilization. Additionally, it mentions the plant’s pest resistance and propagation methods. Original publication date October 1999.

Effects of different emergent macrophytes on methane flux and rhizosphere microbial communities in wetlands

Emergent macrophytes are of great importance for the structure and functioning of wetland ecosystems and play a significant role in environmental improvement, element cycling, and greenhouse gas (GHG) emissions. However, our understanding of how GHG fluxes differ among macrophyte species and its links with the microbial communities remain limited. In this study, we investigated the rhizosphere microbial communities (including total bacteria, methanotrophs, and methanogens) and the GHG fluxes associated with four emergent macrophytes—Phragmites australis, Thalia dealbata, Pontederia cordata, and Zizania latifolia—collected from Xuanwu Lake wetland, China. We observed the highest CH4 flux (FCH4) (9.35 ± 2.52 mg·m−2·h−1) from Z. latifolia zone, followed by P. australis, P. cordata, and T. dealbata zones (5.38 ± 1.63, 2.38 ± 2.91, and 2.02 ± 0.69 mg·m−2·h−1, respectively). Methanogenesis was methylotrophic at all sites, as the 13C-CH4 values were higher than −64 ‰ and the fractionation coefficients were lower than 1.055. We found a positive linear relationship between FCH4 and the methanogen community, in particular the relative abundances of Methanobacterium and Methanosarcina, indicating that the variations in FCH4 among the studied macrophyte-dominated zones might be attributed to the differences in rhizosphere microbial communities. The methane emissions in various macrophyte zones might be due to the higher capacity of methanogenesis compared to methane oxidation which was inhibited by nutrient-rich sediments. Our findings provide insights for selecting specific emergent macrophytes characterized by low FCH4 in wetland ecological restoration.

Phosphorus uptake and release patterns in overwintering constructed floating wetlands.

Understanding nutrient cycling patterns in plants deployed within constructed floating wetlands (CFWs) is critical for improving CFWs' design and management practices. This study evaluated phosphorus (P) uptake and release patterns during fall/winter plant senescence and spring regrowth. Two mesocosm-scale CFW experiments were conducted characterizing plant growth, plant tissue P levels, and water quality (nutrients and phytoplankton). Experiment 1 quantified P uptake during spring regrowth after overwintering, and experiment 2 quantified P release during fall senescence. Plant treatments (CFWs with Pontederia cordata or Juncus effusus) were compared to an open-water control. In spring, J. effusus removed 0.056 g P m-2 d-1 (19.4% of the load), P. cordata removed 0.034 g P m-2 d-1 (10%), and the open-water control removed 0.03 g P m-2 d-1 (10%). In fall, J. effusus fixed 0.008 g P m-2 d-1 (2.1% of the load), P. cordata released 0.014 g P m-2 d-1 (-2.1%), and controls fixed 0.023 g P m-2 d-1 (6.3%). P was consistently released during the fall experiment and occasionally released in the spring experiment, likely from senescing plant tissues (fall) and from roots sloughing after new root growth (spring). Results demonstrate the potential for multi-season deployment of CFWs using J. effusus for reducing P loads year-round.

A Model System to Evaluate the Potential of Floating Treatment Wetlands to Manage Phytophthora species in Recycled Irrigation Water

Highlights A floating treatment wetland (FTW) planted with Pontederia cordata reduced the flow-through of viable zoospores. Bacterial communities associated with FTWs that differed in remediation efficacy were characterized. FTWs have the potential to reduce plant pathogen load in water recycled for agricultural irrigation. Abstract. The increased incidence and severity of drought have reduced reliable access to freshwater irrigation sources for nursery and greenhouse plant producers. Many plant producers are now considering onsite remediation and reuse of water captured from irrigation return flow. However, potential contamination of recycled water with plant pathogens, primarily species of Phytophthora, is the primary concern preventing many growers from reusing their water. Floating treatment wetlands (FTWs) consist of plants established on a buoyant structure that floats on the surface of a water body with roots extended down into the water column. FTWs effectively remediate nutrients in agricultural runoff, but their potential to manage plant pathogens was previously unknown. Therefore, our objective was to investigate the potential efficacy of FTWs to manage species of Phytophthora in recycled irrigation water. Amplicon sequencing was performed to observe how the bacterial communities associated with the roots of plants in the various FTWs differed. The research was conducted using a controlled model system. Each model FTW consisted of a 3-m-long plastic trough that contained no plants, Agrostis alba plants, or Pontederia cordata plants. Nutrient-amended pond water continuously flowed through each trough at a set hydraulic retention time (HRT) of 1 h or 4 h. A standard inoculum concentration of Phytophthora nicotianae zoospores in aqueous suspension was added to influent water entering each trough, and zoospore activity in effluent water leaving each trough at predetermined time intervals was monitored with a baiting bioassay. Results from this study demonstrated that controlled model FTWs containing P. cordata plants effectively reduced the movement of viable P. nicotianae zoospores through a channel of nutrient-amended water at a target HRT of approximately 4 h. Movement of viable zoospores through the troughs was not reduced at the higher flow rate of 1 h HRT or for FTWs containing A. alba plants. Furthermore, the roots of A. alba and P. cordata had enriched bacterial communities that differed from one another. The mechanism by which FTWs containing P. cordata plants reduced zoospore activity was not determined; however, it may be due to interception of zoospores by plant roots, effects from plant root exudates, interactions with the root microbiome, or differences in water quality parameters. This is the first published study evaluating the potential efficacy of floating treatment wetlands to manage plant pathogens in irrigation water. Keywords: Ecological remediation, Horticulture, Microbial community analyses, Pathogens, Water reuse.

Identification for the species of aquatic higher plants in the Taihu Lake basin based on hyperspectral remote sensing.

Aquatic plants are crucial for aquatic ecosystems and their species and distribution reflect aquatic ecosystem health. Remote sensing technology has been used to monitor plant distributions over large scales. However, the fine identification of the species of aquatic higher plants is challenging due to large temporal-spatial changes in optical water body properties and small spectral differences among plant species. Here, an aquatic plant identification method was developed by constructing a decision tree file in the C4.5 algorithm based on the canopy spectra of eight plants in the Changguangxi Wetland water area from hyperspectral remote sensing technology. The method was used to monitor the distribution of different plants in the Changguangxi Wetland area and two other water areas. The results showed that the spectral characteristics of plants were enhanced by calculating their spectral index, thereby improving the comparability among different species. The total recognition accuracy of the constructed decision tree file for eight types of plants was 85.02%. Nymphaea tetragona, Pontederia cordata, and Nymphoides peltatum had the highest recognition accuracy and Eichhornia crassipes was the lowest. The specific species and distributions of aquatic plants were consistent with the water quality in the area. The results can provide a reference for the accurate identification of aquatic plants in the same type of water area.

Different in root exudates and rhizosphere microorganisms effect on nitrogen removal between three emergent aquatic plants in surface flow constructed wetlands

Swine wastewater contains high concentration of nitrogen (N), causing pollution of surrounding water bodies. Constructed wetlands (CWs) are considered as an effective ecological treatment measure to remove nitrogen. Some emergent aquatic plants could tolerate high ammonia, and play a crucial part in CWs to treat high concentration N wastewater. However, the mechanism of root exudates and rhizosphere microorganisms of emergent plants on nitrogen removal is still unclear. Effects of organic and amino acids on rhizosphere N cycle microorganisms and environmental factors across three emergent plants were investigated in this study. The highest TN removal efficiency were 81.20% in surface flow constructed wetlands (SFCWs) plant with Pontederia cordata. The root exudation rates results showed that organic and amino acids were higher in 56 d than that in 0 d in SFCWs plants with Iris pseudacorus and P. cordata. The highest ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) gene copy numbers were found in I. pseudacorus rhizosphere soil, while the highest nirS, nirK, hzsB and 16S rRNA gene copy numbers were detected in P. cordata rhizosphere soil. Regression analysis results demonstrated that organic and amino acids exudation rates were positive related to rhizosphere microorganisms. These results indicated that organic and amino acids secretion could stimulate growth of emergent plants rhizosphere microorganisms in SFCWs for swine wastewater treatment. In addition, the EC, TN, NH4+-N and NO3−-N were negatively correlated with organic and amino acids exudation rates, and abundances of rhizosphere microorganisms via Pearson correlation analysis. These results imply that organic and amino acids, and rhizosphere microorganisms synergically affected on the nitrogen removal in SFCWs.

Improving the efficacy of different life-form macrophytes in phytoremediation of artificial eutrophic water by combined planting.

Phytoremediation of the eutrophic water bodies by using various macrophytes has long been considered effective and economical. However, the understanding of combining macrophytes to maximize efficacy in the restoration is still limited. In this study, three different life-form macrophytes were employed to explore the optimal plant combination of eutrophic water purification, including Pontederia cordata L. (E: emergent), Pistia stratiotes L. (F: floating), and Hydrilla verticillata (L. f.) Royle (S: submerged). The effects on water quality, removal of the excess nutrients (TN, NH3-N, NO3-N, and TP) in the water, along with the growth response and the nutrient accumulation of the macrophytes were investigated both individually and in combination. The phytoremediation of every single macrophyte was significantly improved by combined planting and increasing the diversity of the combination led to better enhancements. In general, the treatment with macrophytes in three life forms (EFS) not only resulted in the highest removal rates of the TN, NH3-N, NO3-N, and TP (40.89, 33.50, 46.81, and 43.55%, respectively) but also decreased the turbidity and increased the dissolved oxygen more effectively and efficiently. Furthermore, EFS mitigated the environmental stress of plants and promoted the accumulation of TN and TP in them, especially the emergent macrophyte P. cordata. The combinations with macrophyte in two life forms (EF, ES, and FS) also exhibited unique strengths: the removal efficacy of TN (39.25%) and TP (46.16%) in FS, and NO3-N in EF (48.54%) and ES (49.90%) were also at the forefront; the biomass and nutrient content of the submerged macrophyte H. verticillata in ES were the highest. Moreover, a strong correlation between the eutrophic factors and the plant physiological indexes was observed. These findings highlighted the role of combined planting in phytoremediation and provided a valuable reference for the development of ecological restoration for eutrophic ecosystems.

Efficient removal mechanism of an electrical conductivity-enhanced constructed wetlands under particle accumulated conditions

The performance of constructed wetland (CWs) systems should improve through the electrochemistry of microorganisms, with the help of conductive fillers. To explore the strengthening mechanism of the CWs, three comparative experiments, including Co CWs (electro-conductive materials coke as filler), Co-P CWs (coke as filler with pickerel weed (Pontederia cordata L)), and QS-P CWs (quartz sand as filler with pickerel weed (Pontederia cordata L)), were tested to investigate the influence of the clogging process on the purification capacity from the electrochemical characteristics and the community of microorganisms in domestic sewage. The results showed that coke, as an electro-conductive filler, had the best organic removal and high electric output, even with solid particle accumulation. Co-P CWs were the most stable and had the best removal efficiency of COD (chemical oxygen demand) in urban sewage, with an average removal rate of 74.9% at 7 weeks, which was 14 and 7.3% higher than those of the QS-P CWs and Co CWs, respectively. The power generation performance of the Co-P CWs was also the best. During operation, the voltage remained the highest (377.9–222.0 MV). The microbial community diversity, richness, and utilization rate of the six categories of carbon sources of Co-P CWs were the highest, with the dominant genera being organic matter aerobic degrading bacteria, electrochemically active bacteria, and ammonia-oxidizing bacteria. The microbial richness in coke CWs exhibited high microbial activity in the entire bed, not only at the inlet. This indicates that the system transfers electrons to the conductive material by relying on the metabolism of microorganisms; electrons generated at the bottom of the bed are directly transmitted to the bed surface through the conductive material, resulting in a uniform distribution of electrons throughout the bed and high microbial activity. Therefore, the conductivity-enhanced CWs effectively alleviated the reduction in wetland purification capacity.

Where are the seeds? Lack of floral morphs prevent seed production by the tristylous Pontederia cordata in South Africa.

Reproduction is a crucial part of the successful establishment and spread of an invasive species. Invasive plants often produce seeds prolifically to spread into new ranges, yet the invasive macrophyte, Pontederia cordata L., does not appear to produce seeds in South Africa, limiting its invasive potential. Here, we aimed to determine what limits seed production of the tristylous P. cordata in South Africa, where it is widespread with impacts on the ecology of wetlands it invades, South Africa. We measured floral traits and pollen grain size from populations throughout the invasive range in South Africa to determine the relative proportion of tristylous morphs. We speculated that the absence of specialist native pollinators in the invasive range may be responsible for the absence of sexual reproduction and thus conducted a pollination study to determine whether flowers were visited. Thereafter, we hand pollinated 8865 flowers to conclude whether P. cordata exhibited an incompatibility system, which prevented seed production. The floral traits and pollen grain measurements were similar to those reported for short‐morphed flowers from the native range. The pollination study confirmed the absence of specialist insect visitors, while the hand‐pollination experiments resulted in no seed production. Only short‐morphed plants are present in South Africa, and the illegitimate pollination of short‐morphed plants prevents seed production. Vegetative spread through rhizome production is thus responsible for the invasion of P. cordata throughout South Africa. These findings suggest that control programs should target the plants' rhizomes to prevent and reduce spread. More importantly, preventing the introduction of medium‐ and long‐morphed plants into South Africa is crucial to preclude P. cordata from producing seeds and enhancing invasion.

Removal and kinetics of basic pollutants in serially constructed wetlands

In this research, the spatial distribution and kinetic coefficient of basic pollutants in the artificial wetlands (CW) of the DACBiol-UJAT wastewater treatment plant were evaluated. It consists of a sump-settler and two identical modules with HA in series 8.3 m long, 2.5 m wide and 0.5 m long. In both trains, the first HA is subsurface flow (SSFCW) with Pontederia cordata (tule) species, the second HA is free flow (FFCW) with Thalia geniculata (popal) and the last HAFL with Sagittaria lancifolia (dovetail). The characterization of the support medium, water quality (inlet, outlet and internal points), modeling of the spatial distribution and kinetics of color degradation, turbidity and COD were carried out. Both trains operated with a 3-day HRT with a Qmed of 8.9 ± 3.4 m3/day. The quality of the inlet water of train 1 presents an average turbidity of 72.3 UTN, color of 1340.0 UC and COD with 373 mg/L, likewise at the entrance of train 2 the average turbidity is 69.6 UTN, color of 1,190.3 UC and COD with 373 mg/L. The degradation kinetic constant was estimated in train 1 at -0.52 days-1 for turbidity, -0.32 days-1 for color and -0.58 days-1 for COD, for train 2 of -0.47 days-1 for turbidity, -0.24 days-1 for color and -0.49 days-1 for COD. The removal efficiency for turbidity in train 1 was 65.6% and train 2 was 67.9%, for the apparent color in train 1 it was 48.8% and train 2 was 58.3% and in COD in train 1 it was 81% and for train 2 of 76%. The maximum permissible COD limit according to PROY-NOM-001-SEMARNAT-2017 is met, which is 150 mg/L.

An effective planting model to decrease cadmium accumulation in rice grains and plants: Intercropping rice with wetland plants

Cadmium (Cd) pollution affects plant growth and poses a serious threat to food safety and human health. Cadmium-contaminated rice is assumed to be the main source of Cd exposure to humans, with grave health risks. Phytoremediation is an efficient, cost-effective, and eco-friendly approach to minimizing Cd accumulation in rice. However, research on the effect of rice intercropping with wetland plants that exhibit great capacity for phytoremediation in decreasing Cd concentrations in paddies is limited. A pot experiment in glasshouse was conducted to evaluate the effects of rice intercropping with two wetland plants ( Pontederia cordata and Canna indica ) under different Cd levels (0, 1, 10, and 25 mg kg −1 ) on rice growth and Cd accumulation and translocation. The results showed that intercropping with the two wetland plants significantly improved the plant height, tiller, and biomass of rice but reduced the bioconcentration factors (BCFs) and Cd concentration in rice and wetland plants. Compared with rice monocropping, the BCF of rice grain in treatments with 25 mg kg −1 Cd was significantly decreased by 54.39% and 59.65% in rice intercropped with C . indica (RC) and rice intercropped with P. cordata (RP), respectively. In addition, intercropping inhibited the increase in BCFs in rice and wetland plants under increasing soil Cd content. In conclusion, the systems of rice intercropping with P. cordata and C . indica can be considered two new and effective approaches for ameliorating Cd pollution in paddies, as well as minimizing Cd accumulation in rice and improving food safety. Of the two intercropping systems, rice intercropping with P. cordata performed better than intercropping with C . indica.

Responses of a tidal freshwater marsh plant community to chronic and pulsed saline intrusion

Abstract Climate change causes both chronic and pulsed environmental changes to ecosystems. In estuaries, tidal freshwater marshes experience both extended and episodic periods of elevated salinities due to sea level rise, reduced river discharge during drought and storm surge, but most research has focused on extended (press) perturbations. Over a 4‐year period, we added diluted seawater to replicated plots in a tidal freshwater marsh in Georgia, USA to raise porewater salinities from freshwater to oligohaline. We assessed the ecosystem effects of press (continuous) and pulse (2 months per year) changes in salinity by measuring the responses of dominant angiosperms, benthic microalgae and dominant macro‐invertebrates (fiddler crabs). We transplanted angiosperms typical of oligohaline and mesohaline conditions into plots as bioindicators (phytometers) to assess potential for vegetation changes over longer time periods. In the press treatment, the cover of all common plant species decreased. Ludwigia repens almost disappeared within the first month; Polygonum hydropiperoides nearly disappeared within the first growing season; Pontederia cordata and Zizaniopsis miliacea declined over the 4 years but did not completely disappear. The decline in the four most dominant plant species decreased total above‐ground plant biomass, leading to an increase in light penetration and increased densities of benthic diatoms and cyanobacteria. The density of fiddler crab burrows was not significantly affected by the treatments, but was positively related to above‐ground plant biomass across all replicates. Transplant experiments indicated that plants typical of higher salinity conditions (e.g. Schoenoplectus sp.) performed well under conditions prevalent in the press plots. In the pulse treatment, only L. repens declined, and there was no effect on community‐level above‐ground biomass or other community variables. Synthesis. Our results indicate that tidal freshwater marsh plant and animal communities are vulnerable to extended periods of salinization but resilient to short saline pulses. Although saline pulses did not impair most ecosystem functions, the decline in a single species (L. repens) in the pulse treatment was associated with reduced marsh accretion and no elevation gain—factors which must be positive for wetland survival in an era of rising seas. Thus, periodic salinization may threaten the long‐term persistence of freshwater wetlands even before dramatic changes in community structure occurs.

Growth of micropropagated Pontederia cordata using broadband white light with or without far-red radiation

Growth of micropropagated <i>Pontederia cordata</i> using broadband white light with or without far-red radiation

Transcriptional, secondary metabolic, and antioxidative investigations elucidate the rapid response mechanism of Pontederia cordata to cadmium

Pontederia cordata is previously demonstrated a cadmium (Cd) tolerant plant, and also a candidate for the phytoremediation of heavy-metal-contaminated wetlands. A hydroponic experiment was used to investigate variations in photosynthetic gas exchange parameters, antioxidative activities, chlorophyll and secondary metabolite contents, and transcriptome in leaves of the plant exposed to 0.44 mM Cd2+ for 0 h, 24 h, and 48 h. Under Cd2+ exposure for 24 h, the plant presented a favorable photosynthesis by maintaining relatively higher antioxidant activity. Cd2+ exposure for 48 h accelerated membrane peroxidation, declined photosynthetic pigment content, and increased polyphenol oxidase activity, thus interfering with photosynthesis. The phenylpropane pathway served as a chemical rather than physical defense against Cd2+ in the plant leaves. A total of 20,998, 4743, and 4413 differentially expressed genes (DEGs) were identified in the groups of 0 h vs 24 h, 0 h vs 48 h, and 24 h vs 48 h, respectively. The primary metabolic pathways of the DEGs were mainly enriched in nitrogen metabolism, starch and sucrose metabolism, fructose and mannose metabolism, as well as pentose-phosphate pathway, contributing to a stable cell structure and function. Flavonoid biosynthesis directly or indirectly played an antioxidative role against Cd2+ in the leaves. Forty-nine transcription factor (TF) families were identified, and 8 TF families were shared among the three groups. The present study provides a theoretical foundation for investigating tolerance mechanisms of wetland plants to Cd stress in terms of secondary metabolism and transcriptional regulation.

Potential Susceptibility of Six Aquatic Plant Species to Infection by Five Species of Phytophthora.

Investigations of the susceptibility of aquatic plants to species of Phytophthora are limited. Therefore, the objective of this study was to assess the potential susceptibility of six aquatic plant species, frequently used in constructed wetlands or vegetated channels, to infection by five species of Phytophthora commonly found at nurseries in the southeastern United States. In a greenhouse experiment, roots of each plant species (Agrostis alba, Carex stricta, Iris ensata 'Rising Sun', Panicum virgatum, Pontederia cordata, and Typha latifolia) growing in aqueous solutions were exposed to zoospores of each of the species of Phytophthora (Phytophthora cinnamomi, Phytophthora citrophthora, Phytophthora cryptogea, Phytophthora nicotianae, and Phytophthora palmivora). Zoospore presence and activity in solution were monitored with a standard baiting bioassay with rhododendron leaf discs as baits. Experiments were initiated in 2016 and repeated in 2017 and 2018. During the 2016 trials, Phytophthora spp. were not isolated from the roots of any of the plants, but some roots of C. stricta, P. virgatum, and T. latifolia were infected with multiple species of Phytophthora during trials in 2017 and 2018. Presence of plant roots reduced the percentage of rhododendron leaf discs infected by zoospores of four of the species of Phytophthora but not those infected by P. cinnamomi, which suggested that roots of these plants negatively affected the presence or activity of zoospores of these four species of Phytophthora in the aqueous growing solution. Results from this study demonstrated that certain aquatic plant species may be sources of inoculum at ornamental plant nurseries if these plants are present naturally in waterways or used in constructed wetlands treating water flowing off production areas, which could be of concern to plant producers who recycle irrigation water.

Purification Effects on β-HCH Removal and Bacterial Community Differences of Vertical-Flow Constructed Wetlands with Different Vegetation Plantations

This study aimed to investigate the removal of β-hexachlorocyclohexane (β-HCH) at realistic concentration levels (10 µg/L) in different plant species in constructed wetlands (Acorus calamus, Canna indica, Thalia dealbata, and Pontederia cordata) and the structure of the rhizosphere microbial community response of each group during summer and winter. Results showed that all groups of constructed wetlands had very good decontamination efficiency against β-HCH in water (90.86–98.17%). The species that most efficiently purified β-HCH in water was A. calamus in summer (98.17%) and C. indica in winter (96.64%). Substrate sorption was found to be the major pathway for β-HCH removal from water in the constructed wetlands. The ability of the wetland plants to absorb and purify β-HCH was limited, and C. indica had the strongest absorptive capacity among the four plant species. The mean β-HCH removal from the matrix of the planted plants increased by 5.8% compared with that of the control treatment (unplanted plants). The average β-HCH content in the plant rhizosphere substrate was 4.15 µg/kg lower than that in the non-rhizosphere substrate. High-throughput sequencing analysis revealed significant differences (P &lt; 0.05) in the Chao1 and ACE indices of microbes in the substrate of four wetlands during summer and winter. At the genus level, the constructed wetlands with vegetation plantations showed higher microbial abundance than the constructed wetlands without vegetation plantations. In winter, the bacterial community structure of each constructed wetland was quite different, but no dominant flora in the bacterial community structure obviously changed. In summer, the bacterial community structure at the same stage was relatively small. The abundance of Actinobacteria and Sphingomonas remarkably increased over time in summer.

Cadmium Uptake, In Vivo Metastasis and Subcellular Environmental Response of Five Wetland Plants Using DFT Method

The main purpose of this study is to analyze whether Cd2+ affects the absorption of Ca2+ and Fe2+ by the roots of five wetland plants and the toxic mechanism of cadmium on the subcellular structure. Five wetland plant samples were collected from the constructed wetland in the upper reaches of the Yangtze River. Based on the experiment and density function theory (DFT), we measured the Cd2+ content in the root, stem, and leaf, the morphological dimensions of plants, and in the subcellular structure the electronic activity of Cd compound was calculated to describe the stability and activity of the products. In general, Zephyranthes candida,Cynodon dactylon, Arundo donax, and Pontederia cordata have distinct cadmium uptake characteristics, while Phragmites communis does not. The results indicated tolerance to cadmium in all but Phragmites communis, which was due to cadmium distribution through the process of transpiration and a mechanical interception. The simulation results showed that Cd2+ imposed no obvious inhibition on the absorption of Ca2+ and Fe2+ in plants, as the energy barrier of the process is about 1–3 eV. Cd2+ could improve the amount of pyruvate and glucose by 30% via spd orbital hybridization, making them more chemically reactive. At the same time, Cd2+ could replace Mg2+ in chlorophyll through a copper substitution reaction, making the electron energy of chlorophyll more concentrated. As a result, the valence-band electron at −40 eV was vacant. In conclusion, we determined that Cd2+ has no obvious inhibitory effect on Ca2+ and Fe2+ in root absorption and that Cd2+ could affect the properties of compounds of the subcellular structure and thus produce physiological toxicity.

Phytoremediation of azoxystrobin and imidacloprid by wetland plant species Juncus effusus, Pontederia cordata and Sagittaria latifolia

Azoxystrobin (strobilurin fungicide) and imidacloprid (neonicotinoid insecticide) have been detected in surface waters near treated agricultural, urban, and mixed landscapes. The hazards of pesticide runoff can be prevented through best management practices, including the establishment of diverse wetland plant barriers that can phytoremediate the chemicals in which they come into contact with. In this study, the wetland plant species softrush (Juncus effusus), pickerelweed (Pontederia cordata), and arrowhead (Sagittaria latifolia) were planted in sandy soil containers that were then placed in azoxystrobin or imidacloprid treated water. Every week for 2 months, water samples were collected for pesticide residue analysis using high-performance liquid chromatography (HPLC). At 14, 28, and 56 days after initiation, plants were destructively harvested and analyzed for pesticide residue in soil, above-ground vegetation, and below-ground vegetation. Results from this study report P. cordata reduced greater azoxystrobin (51.7% reduction compared to treated non-planted containers) compared to J. effusus and S. latifolia (24.9% and 28.7% reduction from non-planted containers) at 56 days. However, S. latifolia reduced greater imidacloprid (79.3% reduction compared to non-planted containers) compared to J. effusus and P. cordata (36.0% and 37.1% reduction from non-planted containers) at 56 days. Novelty statement: While research has found that wetland plants can absorb and remediate synthetic chemicals, this practice is only sustainable if used with native plants that require low maintenance and are tolerant to the applied substances. Various previous studies observe plants that are fast-growing, tolerant to environmental conditions, require low-maintenance, and are hardy. However, these plant species are not always suitable for any location and are often considered invasive and/or weed-like. The present research initiates a list of plant species which can be used within the southeastern United States and similar areas to phytoremediate commonly used pesticides azoxystrobin and imidacloprid and prevent off-target movement into sensitive water systems.

Reduced pests, improved grain quality and greater total income: benefits of intercropping rice with Pontederia cordata.

Intercropping, which is growing two or more different crops in the same field simultaneously, is an effective traditional agricultural practice for productivity, resource utilization, and pest control. However, study on intercropping in paddy fields is limited. So in this study, field experiments of 2 years/four seasons (early and late seasons in 2016 and 2017) were conducted to examine the effects of rice-Pontederia cordata intercropping on rice plant growth, pest control, yield, income, and grain quality. We found rice-P. cordata intercropping significantly decreased the occurrence of rice diseases and pests, with a 22.0-45.9% reduction in sheath blight and a 33.8-34.4% reduction in leaf folders. The mean land equivalent ratio (LER) (1.09) result indicates that intercropping rice and P. cordata generated positive yield effects. In addition, due to the economic profit from the replacement stripe of P. cordata in the rice paddy field, intercropping rice with P. cordata could greatly enhance farmer income. The average total income of rice intercropped with P. cordata was 2.5-fold higher than that of rice monoculture. Furthermore, intercropping significantly improved grain quality compared with the rice monoculture. It significantly increased the milled rice rate and whole milled rice rate by 11.2% and 12.8%, respectively, but decreased the chalky rice rate by 30.9-39.8% and chalkiness degree by 32.2%. We suggest that rice-P. cordata intercropping provides an environmentally effective way to control rice diseases and pests, results in higher overall productivity and total income, and improves grain quality. © 2021 Society of Chemical Industry.

A comparison of the mechanisms and performances of Acorus calamus, Pontederia cordata and Alisma plantagoaquatica in removing nitrogen from farmland wastewater

This study examined the performances of Acorus calamus, Pontederia cordata, and Alisma plantagoaquatica in removing nitrogen (N) from farmland wastewater. P. cordata showed the fastest rate of N removal, followed by A. plantagoaquatica, whereas that of A. calamus was slowest. P. cordata and A. plantagoaquatica achieving a greater rate of TN reduction in soil than that by A. calamus. A. plantagoaquatica demonstrated the highest N adsorption capacity, 32.6% and 392.1% higher than that of P. cordata and A. calamus, respectively. The higher potential nitrification and denitrification rate, and abundance of functional genes in the P. cordata microcosm resulted in a stronger process of nitrification–denitrification, which accounted for 65.99% of TN loss. Plant uptake and nitrification–denitrification were responsible for 50.06% and 49.94% of TN removed within the A. plantagoaquatica. Nitrification-denitrification accounted for 86.35% of TN loss in A. calamus. These findings helped to insight into N removal mechanisms in different plants.