Pistia Research Articles

Air and oxy-fuel incineration disposal of invasive biomass water lettuce (Pistia stratiotes L.): performance, kinetics, flue gas emissions, mechanisms, and ash characteristics

Air and oxy-fuel incineration disposal of invasive biomass water lettuce (Pistia stratiotes L.): performance, kinetics, flue gas emissions, mechanisms, and ash characteristics

Performance evaluation of hybrid constructed wetlands for nitrogen removal and statistical approaches.

Nitrogen pollution in water bodies has become a pressing environmental and public health issue worldwide, demanding the implementation of effective nitrogen removal strategies. This research paper delves into the performance evaluation of hybrid constructed wetlands (HCWs) as a sustainable and innovative approach for nitrogen removal, employing a comprehensive year-long dataset gathered from a practical setup. The study collected data under diverse operating conditions to investigate the effectiveness of HCWs in removing nitrogen. Results revealed that HCWs achieved nitrogen removal efficiencies ranging from 28% to 65%, influenced by temperature and hydraulic retention time. Optimal removal occurred at an average temperature of 28°C and a 4-day hydraulic retention time. Notably, performance declined during colder periods, with temperatures below 15°C. The study also aims to predict nitrogen removal by three modeling techniques, that is, artificial neural networks (ANNs), support vector machines Pearson VII kernel function (SVM PUK), and multiple linear regression (MLR). Prediction has been done considering temperature (TEMP), hydraulic loading rate (HLR), initial concentration of chemical oxygen demand (COD) (CODin), initial concentration of total nitrogen (TNin ), initial concentration of total phosphorous (TPin ), and initial concentration of turbidity (TBin ) as input parameters, whereas reduction of total nitrogen (RED TN) is regarded as output parameter. The performance of the soft computing techniques has been compared in terms of coefficient of determination (R2 ), root mean square error (RMSE), and mean absolute error (MAE). The analysis revealed that the performance of the SVM (PUK) model (R2 : 0.572, RMSE: 0.0359, MAE: 0.0294) for the prediction of TN reduction is superior followed by MLR (R2 : 0.562, RMSE: 0.0365, MAE: 0.0294) and ANN (R2 : 0.597, RMSE: 0.0377, MAE: 0.0301). The present study concludes that the treated effluent by the HCWs, using water hyacinth and water lettuce, is of fair quality, thus having potential application for the treatment of rice mill wastewater in warmer climates. Further, machine learning approaches employed in estimating the total nitrogen reduction by HCWs technology have shown promising applicability and utilization in such studies. PRACTITIONER POINTS: Hybrid constructed wetlands (HCWs) are effective in removing nitrogen from wastewater. The performance of HCWs in nitrogen removal can vary due to physical, chemical, and biological processes. The performance of the HCWs highly depends on temperature and hydraulic retention time. Artificial neural networks (ANNs) and support vector machines (SVMs) provided better predictions of nitrogen removal with high accuracy and low root mean square error.

An Ecological Assessment of Invasive Alien Plant Species in Jokhar Lake Area of Kailali District, Nepal

Invasive alien plant species (IAPS) have been creating adverse impacts on native diversity. Diversity of Nepal’s wetland ecosystems are also threatened by several IAPS but the related studies are very scarce. This study has assessed the status of IAPS found in Jokhar Lake of Kailali district, Nepal. The IAPS survey was carried out by sampling 30 plots of (1×1)m2 each in and around the lake area. A total of 17 species of IAPS were reported from the study site. Most of the IAPS were the members of the family Asteraceae. The diversity of IAPS in the lake represents about 65% of the total IAPS in Nepal. Around the lake periphery, Ageratum houstonianum and Argemone mexicana and inside the lake Eichornia crassipes and Pistia stratiotes were major IAPS. The natural beauty of the lake has been ruined by these IAPS. A detailed study on the impacts and ecology of these IAPS in the lake and lake periphery is still lacking. Hence, it is recommended that the IAPS in the lake area should be controlled to conserve the native diversity and the natural beauty of the lake.

Synergism of Consortium of Heterotrophic Bacterial Strains with Pistia stratiotes L. and Salvinia molesta D. Mitch as Biophytoremediator for Heavy Metal Removal in Domestic Wastewater

High levels of organic matter and heavy metals in domestic wastewater can increase the pollution of water bodies. The water pollution results correspond to the degree of public health. Waste must be controlled and processed first using management methods such as biophytoremedyator to decrease the rate of pollution because its advantages do not negatively impact public health and the environment. Biophytoremediation offers a better alternative method to repair environmental conditions by combining microorganisms and plants. This study aimed to analyze the effect of heterotrophic bacterial strains with Pistia stratiotes L. and Salvinia molesta D. Mitch for heavy metal removal in domestic wastewater. It also investigated the influence of heterotrophic bacterial strains with Pistia stratiotes L. and Salvinia molesta D. Mitch which were also carried out to observe the BOD and COD levels. The results showed decreased heavy metal levels from the three treatment groups. The consortium treatment group of heterotrophs and Salvinia molesta D. Mitch bacteria strains reduced heavy metal levels faster than the other groups by 59%. In addition, it is also able to reduce BOD and COD levels. This study has shown the significant effect of combining heterotrophic bacterial (HB) strains with Pistia stratiotes L. or Salvinia molesta D. Mitch for heavy metal removal in domestic wastewater.

Implementation of water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) in the re-treatment of conventionally treated pharmaceutical wastewater: a case study of Radiant Pharmaceuticals Limited, Dhaka, Bangladesh.

Since Bangladesh already has robust pharmaceutical industries, nearly all companies owned effluent treatment plant (ETP) facilities to improve the quality of wastewater. Water retreatment utilizing affordable, accessible, and environmentally sustainable techniques have not yet been thoroughly investigated. In this study, the potential of water hyacinth and water lettuce was investigated at three different concentrations: 50% of total volume coverages (1000g macrophytes/2000ml water), 75% of total volume coverages (1500g macrophytes/2000ml water), and 100% of total volume coverages (2000g macrophytes/2000ml water) on the post-treated ETP's wastewater for 3weeks in a mesocosm environment. Heavy metals, such as chromium (Cr) and nickel (Ni) along with physicochemical parameters (pH, EC, TDS, DO, and BOD5) were measured after 7days intervals. Results indicated that water hyacinth was considerably more efficient than water lettuce at removing many factors, including metals. Water hyacinth was able to remove 79.15% of nickel and 92.97% of chromium while also increasing DO and EC by 36.72% and 14.59%, respectively, at 100% of total volume coverages. On the other hand, 100% of the total volume coverage of water lettuce decreased the pH, TDS, and BOD5 readings by 6.70%, 31.62%, and 87.61%, respectively. With each treatment, the water quality significantly improved over the control. The findings suggest that the pharmaceutical industries may improve the quality of their treated wastewater even more by integrating phytoremediation technology with traditional ETP facilities.

Coefficient Test of Antimicrobial Phenol Combination of Eichhornia crassipes and Pistia stratiotes Extract In Vitro as Alternative Disinfection Candidates

Eichhornia crassipes and Pistia stratiotes are weeds that often pollute water areas. These two contain various active compounds that act as antimicrobials, which have the potential as disinfection agents to prevent the transmission of pathogenic bacteria and fungi. An antimicrobial substance is said to be effective as a good disinfectant if it has a phenol coefficient value equal to or more than the 5% phenol comparison substance. The aim of this research was to test the effectiveness of a combination of Eichhornia crassipes and Pistia stratiotes extracts as a disinfection candidate through the phenol coefficient test. This in vitro experimental study was carried out using a dilution technique. The combination treatment of Eichhornia crassipes and Pistia stratiotes extracts and 5% phenol was tested against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi and also Candida albicans yeast. Observations on the test media suspension tubes that were clear or did not show the growth of the test microbes for a period of 5, 10, and 15 minutes. The phenol coefficient value of the combination treatment of Eichhornia crassipes and Pistia stratiotes extracts was ≥1 with 5% phenol as comparison. Higher coefficient values were obtained for Staphylococcus aureus, equivalent values of 5% phenol were found for E.coli, P.aeruginosa, and C.albicans; whereas in S.typhi the value is <1. The combination treatment of E.crassipes and P.stratiotes extracts resulted in a phenol coefficient value equivalent to that of 5% phenol comparator, for several tested bacteria and yeasts. So it has effectiveness as a preparation for disinfection. The combination of Eichhornia crassipes and Pistia stratiotes extracts has antimicrobial effectiveness and can be developed as an alternative disinfection candidate.

Effects of nitric oxide on the phytoremediation of swine wastewater by Pistia stratiotes under copper stress

Nitric oxide (NO) is widely present in wastewater. As a signaling molecule, NO influences many aspects of phytoremediation, especially in response to heavy metal stress. The current understanding of the impact of NO on the tolerance of Pistia stratiotes and other plants to Cu2+ in swine wastewater is limited. This study aimed to investigate the impact of NO on the physiological response of Pistia stratiotes and its efficacy in removing pollutants from swine wastewater under varying concentrations of Cu2+ ranging from 1~4 mg/L. The findings showed that NO treatment reduced copper stress at 2~4 mg/L Cu2+ while increasing oxidative stress at 1 mg/L Cu2+. According to an analysis of physiological parameters and copper concentrations, the results found a significant correlation between increased copper tolerance and elevated levels of antioxidants and transport coefficients. The morphology of copper and the results of the principal component analysis indicate that NO facilitated the humification process of the dissolved organic matter. The investigation found that the removal efficiencies of NH3–N, NO3–N, and total phosphorus in NO treatment were enhanced to 95.76%, 88.72%, and 91.89%, respectively. Collectively, it was determined that NO is a regulator of phytoremediation to copper in wastewater via promoting antioxidative, copper transport, DOM bound, nutrients uptake, thus adequate amount could improve the tolerance of Pistia stratiotes to Cu2+. This study is expected to provide a theoretical basis for rationally regulating NO concentration and effectively improving the removal efficiency of copper in swine wastewater.

Effect of floating plant growth rate on water quality performance of wetland in treating domestic sewage

A man-made system that mimics the function and structures of natural wetlands is called constructed wetlands. It is able to treat sewage water with low technology, low energy requirements, affordable and easy to maintain. However, how it works in tropical climates is still unknown and there is a need to figure out the sustainability of floating plants in treating domestic sewage. This study aims to investigate the pollutant removal efficiency of two selected floating plant species, water hyacinth and water lettuce, in treating domestic sewage. The growth rate of both plants will be examined for the best-recommended plants in the constructed wetland systems for domestic sewage treatment. The data was collected through a pilot-constructed wetland in the USM, Engineering Campus that is integrated with two species of floating plants: water hyacinth and water lettuce. The parameters studied were chemical oxygen demand (COD), total suspended solids (TSS), and ammoniacal nitrogen (AN). The findings reveal that the removal efficiency of water hyacinth is higher for COD and TSS at 40.96 % and 43.94 % respectively compared to Water Lettuce with 26.86 % for COD and 17.79 % for TSS. However, Water Lettuce has a slightly higher removal efficiency of NH3-N at 26.52 % compared to Water Hyacinth at 24.35 %. In terms of growth rate, Water Hyacinth is lost to water lettuce, but they have higher biomass to uptake nutrients with just a small increment of area coverage. Therefore, water hyacinth is favourable to implement in floating plant-constructed wetlands as it needs less maintenance than water lettuce to achieve discharge with standard A for TSS and COD and standard B for NH3-N based on Malaysia Wastewater Effluent Discharge Standards.

Application of Local Species for Sustainable Phytoremediation

Phytoremediation is green technology based on the application of plants to remediate contaminated media. This paper reviews five species of local plants used for phytoremediation in Thailand: Pteris vittata L., Pityrogramma calomelanos L., Chrysopogon zizanioides L., Eichhornia crassipes (Mart.) Solms, and Pistia stratiotes L. For each plant, its pollutant removal efficiency and mechanism is reviewed. The main mechanisms of phytoremediation, such as phytoextraction, rhizofiltration, phytostabilization, phytodegradation, rhizodegradation, and phyto-volatilization, are concisely described. Screening local plants for phytoremediation is a cost-effective and easy to manage approach to derive suitable plants that are resistant to harmful environmental conditions. To be suitable, plants should have a fast growth rate, produce a large biomass yield, have a high tolerance to the toxic effects of the pollutants, and have a good capacity for pollutant uptake. Moreover, applying the proper species for each contaminant enhances the removal efficiency and supports sustainable phytoremediation.

Environment friendly treatment of petroleum hydrocarbon contaminated formation water: Mechanisms and consequences for degradation and adsorption

An innovative approach to remediate oilfield produced water, a major environmental pollutant from the oil and gas industry has been demonstrated in this study. The technique combines: invasive wetland plant (Pistia stratiotes) used in absorbing and metabolizing hydrocarbons present in the oilfield formation water, biosurfactant from indigenous Bacteria making them more accessible for degradation and fertilizer NPK act as biostimulator. The main objectives of this technique are to remediate Total Petroleum Hydrocarbons (TPH) in an environmentally friendly manner to be a potential for the petroleum sector. The success of the technique is supported by the results of GC-MS analysis, which detected no hydrocarbon compounds in treated water. However, after treatment using the proposed combination 90.1% of the TPH was degraded, and the remaining 9.9% was adsorbed by the biomaterials. Thus, this study would present a potential breakthrough in the ongoing battle against pollution caused by the oil and gas industry.

Bioremediation of Tofu Wastewater Using EM4 and Apu Plant (Pistia stratiotes L.)

The number of tofu factories that have been established has resulted in a large amount of waste being produced. Tofu factories that stand on average are small-scale businesses that cannot afford to manufacture their own waste treatment, so that the waste produced is directly disposed into the environment without processing, this can pollute the environment. Waste treatment can be done in a simple way that doesn't require a lot of money, such as bioremediation using EM4 and Apu plant (Pistia stratiotes L.). The aim of this research was to study bioremediation of tofu wastewater in reducing BOD, COD and TSS levels using Effective Microorganism-4 (EM4) and Apu plant (Pistia stratiotes L.). This research using experimental method and Completely Randomized Design (CRD), with 3 treatments (P1, P2 and P3) that is P1 as the control treatment (without EM4 and Apu plant), P2 as the bioremediation treatment using EM4, and P3 as treatment using Apu plant (Pistia stratiotes L.). Each treatment was repeated 7 times. Parameters measured included pH, BOD, COD and TSS of the waste before and after treatment. Observational data were analyzed by ANOVA test then tested by LSD test. The research results showed that there were differences in bioremediation using Effective microorganism-4 (EM4) and Apu plant (Pistia stratiotes L.) but it was not yet effective in reducing BOD, COD and TSS levels in tofu wastewater. The treatment was ineffective because the remediation results still did not meet the quality standarts in East Java Governor Regulation No 52 of 2014.Keywords: EM4, Pistia stratiotes L., tofu wastewater, waste treatment.

Phytoremediation Using Different Numbers of Individual Kayu Apu Plant (Pistia stratiotes) in Reducing Lead (Pb) Levels in Paper Recycling Factory Waste

Recycled paper mill waste contains inorganic materials, one of heavy metal lead. Metal lead is non-essential and non-degradable that harmful to living things. Reduce lead levels by using Kayu Apu plants (Pistia stratiotes) is needed. The aims, to determine number of Kayu Apu plants that effective in reducing lead levels, temperature and pH of optimum waste according to quality standards, increase in plant's wet weight, and morphological condition of plants. Method is experiment with completely randomized design. Treatment consisted of number of Kayu Apu plants A: control, B: 2 individuals, C: 5 individuals, and D: 9 individuals with 3 replications. Acclimatization of Kayu Apu plant was carried out, measuring physical, chemical and biological parameters, then data were analyzed using one-way ANOVA and paired sample t-test. Results showed that lead levels of treatment using 9 individuals decreased while in control, 2 individuals and 5 individuals increased. Average temperature and pH of waste are still optimum according to quality standards. Average fresh weight of plants increased in treatments B and C, while treatment D decreased. Number of Kayu Apu plants that effective in reducing lead was treatment using 9 individuals. Average temperature and pH of waste were optimum according to quality standards. Wet weight of plants increased in treatments B and C while D decreased. Morphology of Kayu Apu leaves in all treatments turned yellow, dried and fall off but the buds grow.Keywords: Kayu Apu (Pistia stratiotes), lead (Pb), Paper mil waste

Synthesis, characterization and impact of cadmium sulfide nanoparticles on the growth, pigment content and anti-oxidative defence system of Pistia stratiotes

Cadmium Sulfide nanoparticles (CdS NPs) were synthesised and their characteristics were evaluated using XRD (X-ray diffraction), FTIR (Fourier transform infrared), FESEM (Field emission scanning electron microscopy), EDAX (Energy Dispersive X-ray Analysis), and UV-Vis (Ultraviolet-visible). Further, the impacts of CdS NPs on the growth, pigment content and antioxidative defence system of Pistia stratiotes were studied. The exposure of CdS NPs to Pistia stratiotes caused the negative repercussions, which were tested using a variety of biological tests. The findings demonstrated that CdS NPs were hazardous to the Pistia plant at high concentrations, while they were easy to grow at lower concentrations up to 30 ml/l. Both growth and colour characteristics declined at 40 mg/l concentration of CdS NPs. Antioxidant enzymes' activity like superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT) also decreased at 40 ml/l on 60 days. The Protein and photosynthetic pigments were declined on 60 days at 40ml/l concentration however, the level of both the parameters was found increased in comparison with control. The results demonstrated that the higher concentrations of CdS NPs are toxic to Pistia, resulting in decreased growth and significant alterations in antioxidant enzyme activity. These findings suggest that Pistia can be used as a bio-indicator for CdS NPs contaminated water.

Oxygen consumption and formation of recalcitrant organic carbon from the decomposition of free-floating macrophyte leachates.

Aquatic macrophytes contain high levels of hydrosoluble compounds. These compounds disproportionately support microbial breakdown and affect biological oxygen demand in eutrophic waters. In this study, we investigated the fate of leachates from free-floating macrophytes (Pistia stratiotes and Eichhornia crassipes) usually present in eutrophic tropical lacustrine environments. After extraction, the leachates were fractioned into high and low molecular weight compounds and incubated under aerobic conditions, in the dark and at 20.0 ± 1.3°C. The concentrations of dissolved oxygen and the total, dissolved, and particulate organic carbon (TOC, DOC, and POC) were determined during 60days. The selected leachates supported the detritus trophic chain of the Barra Bonita Reservoir. High rates of carbon transfer were measured, which were ascribed to the temperature selected (20°C), nutrient availability, and labile fractions of the leachates. Decomposition occurred mainly through catabolic pathways (mineralization), with the formation of POC (immobilization) being only minor. In the early stages of P. stratiotes and E. crassipes decomposition, the mineralization of leachates (mainly the low molecular weight) led to declines in dissolved oxygen. Owing to the low rates of mass loss, the recalcitrant fractions of these leachates should constitute the main forms of organic carbon exported from the reservoir.

Phytoremediation Technology for Heavy Metal Removal from the Environment

Anthropogenic activities, industrialization, and urbanization have contributed extensively to the enhanced pollution levels in theenvironment. Along with soil and water pollution, air pollution is also escalating and contamination with heavy metals (HMs) isdangerous for the environment since it has negative impacts on people, animals, plants, and the ecosystem. HMs derive their origin from natural and anthropogenic sources. Commercial activities like processing of metals, mining, automobiles, geothermal energy plants, manufacturing industries, tanning, dyeing and plating are the sources of HM contamination. The non biodegradable, permanent inorganic chemical components recognized as HMs are typically harmful at small doses even in humans. HM toxicity leads to carcinogenic effects, developmental and reproductive damage, cardiovascular ailments, haematological, respiratory and nervous system disorders, inflammation and gastrointestinal troubles etc. The absorption and accretion of these metals cause oxidative stress and molecular damage, cytotoxic and mutagenic effects, growth reduction and physiological disorder in plants. Therefore considering their toxic effects, various mechanical as well as physio-chemical technologies are employed for metal removal from the air, water and soil but these techniques have their own limitations and environmental consequences. Hence, phytoremediation is considered an innovative, potentially promising technology employing majorly green plants. The various phytoremediation techniques involve phytoextraction, phytostabilization, phytodegradation, phytotransformation, phytovolitization, and rhizofiltration. Employing these techniques, plants can remove contaminants through a variety of processes, including adsorption, absorption, transport and translocation, hyper-accumulation, transformation, and mineralization. While phytoremediation of air pollutants is still an emerging technology, assimilation properties of plants to convert a toxicant into non-toxic forms have been used extensively for phytoremediation of air. Plants like Morus alba and Eucalyptus globulus can efficiently remove metallic pollutants from air. Moreover, aquatic macrophytes like Eichhornia crassipes,Spirodela polyrhiza, Pistia stratiotes, Azolla, Lemna minor, and Salvinia herzogii are potentially used for cleanup of the HMs in water, while Brassica juncea, Thlaspi caerulescens, Jatropha curcas, Pteris vittata, Vetiveria zizanioides, Gentiana pennelliana, Ambrossia artemisifolia etc. display tremendous well known phytoremediation activity in soil. Phytoremediation is an innovative, aesthetically pleasing, nonintrusive, sustainable and cost-effective technology. Furthermore, due to the disadvantages like high maintenance cost, extensive labor requirement and risks involved in existing conventional technologies associated with pollution abatement, phytoremediation technique can act as a potential, cost-effective and efficient method for water, soil as well as air pollution control.

Water lettuce (Pistia stratiotes L.) increases biogas effluent pollutant removal efficacy and proves a positive substrate for renewable energy production.

Aquatic plants play a crucial role in nature-based wastewater treatment and provide a promising substrate for renewable energy production using anaerobic digestion (AD) technology. This study aimed to examine the contaminant removal from AD effluent by water lettuce (WL) and produce biogas from WL biomass co-digested with pig dung (PD) in a farm-scale biogas digester. The first experiment used styrofoam boxes containing husbandry AD effluent. WLs were initially arranged in 50%, 25%, 12.5%, and 0% surface coverage. Each treatment was conducted in five replicates under natural conditions. In the second experiment, WL biomass was co-digested with PD into an existing anaerobic digester to examine biogas production on a farm scale. Over 30 days, the treatment efficiency of TSS, BOD5, COD, TKN, and TP in the effluent was 93.75-97.66%, 76.63-82.56%, 76.78-82.89%, 61.75-63.75%, and 89.00-89.57%, respectively. Higher WL coverage increased the pollutant elimination potential. The WL biomass doubled after 12 days for all treatments. In the farm-scale biogas production, the biogas yield varied between 190.6 and 292.9 L kg VSadded-1. The methane content reached over 54%. WL removed AD effluent nutrients effectively through a phytoremediation system and generated significant biomass for renewable energy production in a farm-scale model.

Efektivitas kombinasi Pistia stratiotes L. dan Salvinia molesta Mitchell dalam fitoremediasi air asam tambang batubara

Open pit mining is a mining system that is commonly applied to coal extraction activities. Environmental problems in coal mining activities are generally related to acid mine drainage (AMD). Efforts to overcome the impact of AMD can be done by phytoremediation in constructed wetlands (CW). Plants that have the potential for AMD phytoremediation include Pistia stratiotes L (water lettuce) and Salvinia molesta Mitchell (giant Salvinia) , so it is necessary to conduct research on the effectiveness of the combination of P. stratiotes and S. molesta to be developed on CW vegetation. The experimental design used was a completely randomized design (CRD), with 3 treatments using P. Stratiotes, S. Molesta, Combination of P. stratiotes and S. molesta each 9 replications. The results showed the effectiveness of phytoremediation using plant vegetation of P. stratiotes and S. molesta in increasing pH by 40.04% and reducing sulfate levels by 41.72%. The effectiveness of the combination of P. stratiotes and S. molesta in reducing levels of Mn and Fe were 101.36% and 93.49%, respectively. The decrease in TSS levels is better done by the combination of P. stratiotes and S. Molesta vegetation compared to P. stratiotes or S. Molesta vegetation alone, but the better growth rate occurred in S. molesta vegetation only.

Translocation of TiO2 nanoparticles enhances phosphorus uptake by wetland plants: Evidence from Pistia stratiotes and Alisma plantago-aquatica

Titanium dioxide nanoparticles (nTiO2) and phosphorus (P) are widely present in sewages. To verify the hypothesis and the associated mechanisms that root-to-shoot translocation of nTiO2 can enhance plant P uptake thus P removal during sewage treatment, two wetland plants (Pistia stratiotes and Alisma plantago-aquatica) with different lateral root structures were used to examine the effect of nTiO2 (89.7% anatase and 10.3% rutile) on plant growth and P uptake in a hydroponic system. Inductively coupled plasma-optical emission spectroscopy and transmission electron microscopy-energy dispersive spectroscopy showed that P. stratiotes with well-developed lateral roots translocated 1.4–16 fold higher nTiO2 than A. plantago-aquatica with poorly developed roots, indicating P. stratiotes is efficient in nTiO2 uptake. In addition, nTiO2 root-to-shoot translocation in P. stratiotes increased with increasing nTiO2 concentration, while the opposite occurred in A. plantago-aquatica. Corresponding to the stronger nTiO2 translocation in P. stratiotes, its P uptake efficiency (Imax) and P accumulation were greater than that in A. plantago-aquatica, with Imax being increased by 35.8% and −16.4% and shoot P concentrations being increased by 16.2–64.6% and 11.4%, respectively. The strong positive correlation between Ti and P concentrations in plant tissues (r = 0.72–0.89, P < 0.01) indicated that nTiO2 translocation enhanced P uptake. Moreover, nTiO2-enhanced P uptake promoted plant growth and photosynthetic pigment synthesis. Therefore, wetland plants with well-developed lateral roots like P. stratiotes have potential to be used in P removal from nTiO2-enriched sewages.

Effect of different macrophytes on crop cultivation under floating agriculture system for climate change adaptation in Bangladesh

The adverse effects of climate change, including rising sea levels and frequent floods, pose significant challenges to agricultural systems, particularly in low-lying countries like Bangladesh. To address these challenges, floating agriculture systems have emerged as a climate-resilient alternative for crop cultivation. Floating agriculture is a traditional agricultural system where aquatic free-floating macrophytes are used as the medium for the growth of plants. This cultivation system is traditionally used for seedling development in the south and south-western regions (Barishal, Pirojpur, and Gopalganj) of Bangladesh. However, very little scientific attention has been given to using macrophytes in crop production and preparing floating beds. Therefore, the present investigation has been carried out to select suitable macrophytes for preparing a floating bed by assaying the condition of the floating bed and the morphological and yield-related factors of cultivated crops during the Robi season in 2021. Five different macrophytes, namely, Salvinia molesta, Pistia stratiotes, Lemna minor, Salvinia cucullate, and Azolla pinnata, have been used as mulching material, which has been conducted in a Completely Randomized Block Design (RCBD). The plant material BARI tomato-14 has been transplanted on the floating beds to assess the effect of macrophytes on crop production. The results of the present investigation reveal that different macrophytes have distinct effects on tomato plants' growth and yield-related parameters in floating agriculture systems. Salvinia cucullata shows a better response in the stability of the floating bed, whereas Salvinia molesta exhibits better responses as mulching material on yield-related parameters of cultivated crops.

Performance and field host range of the life stages of Cornops aquaticum, a biological control agent of water hyacinth

AbstractHost specificity determination of weed biocontrol agents has historically relied on evidence generated through quarantine trials in the region of introduction. These trials could give ‘false positive’ results due to a maximum type I error probability, and where possible, more research under field conditions should be conducted in the region of origin. The oligophagous, semiaquatic grasshopper, Cornops aquaticum Bruner (Orthoptera: Acrididae, Tetrataeniini), was released in South Africa for the biological control of Pontederia crassipes Pellegrini and Horn (Pontederiaceae). The aim of this study was to assess how the performance and field host range of C. aquaticum varies according to its stages of development, and how this contributes to the understanding of the relationship between the fundamental (laboratory‐based) and the ecological (field‐based) host range of this grasshopper, and its implications for water hyacinth biocontrol. We conducted post‐release laboratory no‐choice trials, confining early instars (instars 1 and 2), later instars (instars 3–6), and adult females and males in mesh cages, to determine insect performance on wetland plants growing in sympatry with P. crassipes. Also, gut analysis from field‐collected C. aquaticum was done to determine the ecological host range of this insect, identifying epidermal tissue of consumed plants. In no‐choice trials, survival rates of the later instars and adult C. aquaticum were similar on Pistia stratiotes L. (Araceae), Oxycaryum cubense (Poepp. &amp; Kunth) Lye (Cyperaceae), and P. crassipes. However, under field conditions, P. crassipes and the congeneric Pontederia azurea Sw. were the only plant contents in the guts of early instars and the most abundant species in later instars and adults. The results support the hypothesis that C. aquaticum is an oligophagous insect on the genus Pontederia, and that different life stages should be considered when conducting host‐specificity trials in externally feeding mobile herbivore species. Diet composition of field‐collected insects thus could help detect false positives in laboratory trials, being an additional and realistic approach in understanding and predicting the selection processes of the insect in the new environment. Retrospective analysis of potential agents that were rejected due to lack of host‐specificity, using the methods from this study, could add a suite of additional agents to programs where invasive weeds remain unmanaged.