Search

Duckweed, a widely used natural fish feed, has also become more popular as the phytoremediation agent for wastewater, including one sourced from aquaculture. These two features indicate that duckweed can be utilized in a sustainable aquaculture system by treating and reclaiming nutrients from wastewater and then harvesting them for fish feed production. Hence, this study attempted to assess the approach of the two most known duckweed species, i.e., Lemna minor and Spirodela polyrhiza, in depleting NH4 and PO4 from synthetic controlled aquaculture wastewater as well as to understand their yield based on the N:P ratio. Cultivation in synthetic aquaculture wastewater media was carried out, followed by nutrient uptake and growth analysis. According to statistical analysis, both L. minor and S. polyrhiza could remove NH4 and PO4 with a relatively equal rate (p-val > 0.050). Nonetheless, both duckweed species absorb nitrogen more easily than phosphorous (p-val < 0.050). Considering the yield based on nutrient uptake, NH4 drove a more efficient yield for L. minor to S. polyrhiza at 16.70 g dry biomass/g NH4 and 14.14 g dry biomass/g NH4, respectively. Meanwhile, a higher yield was observed on S. polyrhiza than on L. minor regarding PO4 concentration, at 19.31 g dry biomass/g PO4 and 9.10 g dry biomass/g PO4, respectively. Therefore, a strategy to remove nutrients and produce biomass for fish feed can be formulated based on the N:P concentration ratio, where L. minor tends to produce biomass more rapidly in a higher N:P ratio, whereas S. polyrhiza works in the opposite. [ABSTRACT FROM AUTHOR]

The phytotoxicity and removal of atrazine and S-metolachlor in sterile duckweed systems were estimated in this study. Herbicides were added at environmentally relevant ranges: 0–400 µg/L for atrazine or 0–200 µg/L for S-metolachlor in systems with Spirodela polyrhiza or Lemna minor. Toxicity biomarkers, i.e., changes in plant biomass, surface area, chlorophyll fluorescence parameters, pigments, lipid peroxidation, protein concentration, and antioxidative enzyme activities in plants were estimated after 7 days. S. polyrhiza (RGRbiomass-EC50 = 164.8 µg/L) was more tolerant to atrazine than L. minor (RGRbiomass-EC50 = 101.0 µg/L). Atrazine caused damage to photosystem II (ΦM), a reduction in electron transport between PSII and PSI (Φ′M), as well as disruption in energy distribution pathways (decrease in qPrel and increase in UQFrel), most prominently in L. minor. However, L. minor (RGRbiomass-EC50 = 128.9 µg/L) was more tolerant to S-metolachlor than S. polyrhiza (RGRbiomass-EC50 = 15.5 μg/L). The highest sensitivity of S. polyrhiza to S-metolachlor was attributed to a decrease in absorbed energy used in photochemistry (qPrel) and an increase in lipid peroxidation, indicating that S. polyrhiza plants were experiencing oxidative stress. Residual pesticide analysis in the water after seven days allowed us to conclude that plants were responsible for reducing up to 16.5% of atrazine and 28.7% of S-metolachlor in the duckweed system. S. polyrhiza showed higher atrazine phytoremediation capacity than L. minor. S. polyrhiza was more efficient at an environmentally relevant concentration of S-metolachlor (25 μg/L) and L. minor at higher concentrations (200 μg/L). [ABSTRACT FROM AUTHOR]

Lemna minuta is native to North America but an invasive alien plant in Europe, where it poses significant threats to freshwater ecosystems. Explorations for biological control agents were conducted in two regions of the United States (Louisiana and California), revealing three candidate species. Subsequent laboratory investigations focused on the weevil Tanysphyrus lemnae and the fly Lemnaphila scotlandae as the most promising agents and confirmed that both the herbivorous insects attack L. minuta plants. To evaluate the host specificity of these two potential agents, insects were exposed to five species of duckweed commonly occurring in North America and Europe. Preliminary host-range testing indicated that T. lemnae develops on all evaluated duckweed species, including those from different genera (Lemna, Spirodela, Landoltia). Conversely, data revealed that feeding and development of the dipteran L. scotlandae are limited to species in the genus Lemna, but this includes L. minor, a native European species threatened in Europe due to the spread of L. minuta. No-choice and choice tests confirmed that neither larvae nor adults of L. scotlandae discriminate between the two Lemna species, except for pupation, which occurs more frequently in L. minor under choice conditions. We conclude that the broad host-range of T. lemnae and L. scotlandae render them unsuitable as biological control agents of L. minuta in Europe. [ABSTRACT FROM AUTHOR]

The increasing global production and utilization of zirconium (Zr) compounds, including zirconium chloride (ZrCl4) and zirconium oxide nanoparticles (NPs-ZrO2), raises concerns about their potential environmental impact. This study investigated the toxicity mechanisms of ZrCl4 and NPs-ZrO2 on the aquatic plant Lemna minor. The physicochemical properties of NPs-ZrO2 in the test medium were characterized, revealing concentration-dependent changes in the hydrodynamic diameter, zeta potential, and solubility over time. The analysis of Zr speciation showed the predominance of Zr(OH)4(aq) species from ZrCl4. Plants of L. minor exposed to ZrCl4 and NPs-ZrO2 exhibited differential Zr bioaccumulation, growth inhibition, oxidative stress, and antioxidant responses. ZrCl4 induced a higher toxicity than NPs-ZrO2, with bioaccumulation strongly correlating with adverse effects. The differential toxicity impact between these two Zr-compounds was also determined by the lowest observed-effect doses for growth and biochemical parameters. The scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy confirmed internalization of NPs-ZrO2 and Zr uptake in the L. minor plant. Therefore, these findings highlighted the importance of chemical speciation, environmental transformations, and biological responses in assessing the ecological impact of Zr-compounds for effective risk assessment and management strategies for protecting aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Triclosan (TCS), an emerging pollutant, is a notable contributor to adverse impacts on aquatic organisms due to its widespread use during COVID-19 and hydrophobic properties. There is extensive documented literature on TCS toxicity in commercially important fish species; however, studies on aquatic plants remain limited. In this prelude, the present study aims to evaluate the effect of TCS on Lemna minor, a commercially important aquatic plant species for 7 days. The results showed dose-dependent significant alterations in growth, pigments and stress enzymes of L. minor at varied concentrations of TCS (1 to 8 mg L−1). Median inhibitory concentration (IC50) was found to be 4.813 mg L−1. Total chlorophyll and carotenoid levels decreased 73.11 and 81.83%, respectively after 7 days of TCS exposure. A significant increase in catalase and superoxide dismutase activity was observed in TCS exposed groups as compared to the control. Bioconcentration factor was found to be in the range of 5.855 to 37.129 signifying TCS ability to accumulate and transfer through the food chain. Scanning electron microscopy (SEM) analysis showed deformation in the cell surface and alteration of stroma morphology of TCS exposed groups. Furthermore, the Fourier transform infrared spectroscopy (FTIR) study also revealed that higher concentrations of TCS could cause alteration in the functional groups in the plant. This study demonstrates that TCS negatively impacts the growth and metabolism of primary producers, offering crucial insights into its interactions with aquatic plants and establishing baseline information essential for crafting effective mitigation strategies for TCS contamination in aquatic environments. [ABSTRACT FROM AUTHOR]

The cheese industry produces substantial amounts of raw cheese whey wastewater (RW), which requires effective treatment prior to environmental disposal. This study presents an innovative sequential batch system that combines macrophyte and microalgal cultivation for RW remediation. The efficacy of Lemna minor MO23 in first-line photobioreactors (PBR-1) and Chlorella sp. MC18 (CH) or Scenedesmus sp. MJ23-R (SC) in second-line photobioreactors (PBR-2) for pollutant removal was evaluated. The nutrient removal capacity of L. minor, CH, and SC was assessed at optimal tolerance concentrations, alongside nutrient recovery from treated RW (TRW) by PBR-1 for microalgae biomass production. The results demonstrate that all three species effectively purified the cheese whey wastewater. L. minor efficiently removed COD, nitrate, phosphate, and sulfate from RW, producing TRW effluent suitable for microalgal growth. CH and SC further purified TRW, enhancing biomass production. CH outperformed SC with a 4.79% higher maximum specific growth rate and 20.95% higher biomass yield. Biochemical analyses revealed the potential of CH and SC biomass for applications such as biofuels and aquaculture. After treatment, the physicochemical parameters of the effluent were within the regulatory limits. This demonstrates that the PBR-1 and PBR-2 series-coupled system effectively purifies and recovers dairy effluents while complying with discharge standards. [ABSTRACT FROM AUTHOR]

The study extended over 60 days to assess the impact of extractive species on improving water quality and enhancing GIFT fish production performance within the FIMTA system. Prior to initiating the experiment, the extraction capacities of both organic and inorganic extractives were assessed. Subsequently, based on these evaluations, GIFT fish were co-cultured with freshwater mussels and aquatic macrophytes as organic and inorganic extractive agents, respectively, within 1000 L FRP tanks. Three treatment combinations were established: GIFT fish with Lemna minor (T1), GIFT fish with Lamellidens marginalis (T2), and GIFT fish with both L. minor and L. marginalis (T3). The control treatment (C) consisted solely of GIFT fish. GIFT fish were stocked at a density of 40 m−2, while L. marginalis at 250 g per tank and L. minor covering 25% of the tank surface. GIFT fish were fed with floating commercial pelleted feed at 4% of body weight (30% CP). The results indicated that among the water quality parameters, chlorophyll a, dissolved solids, and suspended solids showed a reduction in T3. The control group exhibited elevated levels of BOD and COD, whereas the treatment groups showed significantly lower levels. Furthermore, the control group demonstrated increased conductivity levels, while T3 exhibited the lowest levels. In T3, a significant reduction was observed in both POM and POC. Growth variables like SGR and PWG were found to be highest in T3. Regarding enzyme activity, the control group exhibited lower levels of protease, lipase, and amylase, while the highest levels were observed in T3. Physiological enzyme activities such as LDH, MDH, ALP, and ACP were significantly increased (p < 0.05) in the control system, indicating elevated water pollution levels. Meanwhile, bacterial load was found to be very low in the FIMTA system (T3). These findings suggest that the integration of GIFT with L. minor and L. marginalis in the FIMTA system has the potential to enhance water quality and physiological responses, ultimately contributing to higher yields. [ABSTRACT FROM AUTHOR]

Heavy metals pose a significant threat as environmental pollutants, known for their high toxicity. Traditional physiochemical methods for their removal are costly and energy-intensive, making bioremediation a promising alternative. This study aims to assess the potential of duckweed (Lemna minor L.) in removing hexavalent Chromium ((Cr (VI)) from wastewater and examines the impact of Cr (VI) toxicity on the plant's metabolism in aquatic conditions. The experiments were conducted at least three replicates in completely randomized blocks. Various parameters, including Cr concentration (0–100 mg L−1), pH levels (5, 7 and 9), and treatment duration (24–168 h) were investigated to optimize phytoremediation conditions. Physiological and biochemical parameters such as content of photosynthetic pigments, MDA, total phenolics and flavonoid compounds, reducing sugar and polysaccharides, proline and lignin were measured. Additionally, chromium accumulation in plant tissues and residual levels in the culture media were determined using inductively coupled plasma (ICP). After 24 and 168 h, chromium adsorption by L. minor resulted in decreased levels of Cr (VI) in the media. Determination of bioaccumulation factor (BCF) after 168 h indicate higher efficiency of the plant at moderate Cr (VI) concentrations. At higher concentrations of Cr, salinity, EC and TDS increased in the media across all pH condition. The finding revealed exposure to Cr (VI) led to a notable increase in the content of H2O2 (1.2- to 1.7-fold) and MDA (2.2- to 5-fold) in L. minor tissues, particularly evident at pH 9. The contents of total phenolics, flavonoids, lignin and proline (at pH 5 and 7), reducing sugars (at pH 7 and 9) increased; while polysaccharide content was fluctuated. Also, content of photosynthetic pigments decreased by approximately 50% under treatment with 50 and 100 mg L−1 Cr (VI) at pH 5 condition. These responses indicating ROS accumulation as a signal for plant defense mechanism activation. Our results showed that L. minor is tolerant up to 50 mg L−1 Cr (VI), but is susceptible to higher concentrations of this heavy metal. Despite its susceptibility, L. minor proves effective in absorbing Cr (VI) from contaminated waters, highlighting its potential for phytoremediation, albeit requiring careful management for optimal results. [ABSTRACT FROM AUTHOR]

Antibiotics with significant environmental toxicity, e.g., tetracyclines (TCs), are often used in large quantities worldwide, with 50–80% of the applied dose ending up in the environment. This study aimed to investigate the effects of exposure to tetracycline hydrochloride (TC) and minocycline hydrochloride (MIN) on L. minor. Our research evaluated the phytotoxicity of the TCs by analyzing plant growth and biomass and evaluating assimilation pigment levels and fluorescence. The research was extended with the ability potential of duckweed as a tool for removing TCs from water/wastewater. The results demonstrated that both TCs influenced Ir, Iy, biomass, and photosynthetic efficiency. The uptake of TC and MIN by duckweed was proportional to the concentration in the growth medium. The TC was absorbed more readily, reaching up to 8.09 mg × g−1 of dry weight (DW) at the highest concentration (19.2 mg × L−1), while MIN reached 6.01 mg × g−1 of DW. As indicated, the consequences of the influence of TC on plants were slightly smaller, in comparison to MIN, while the plants could biosorb this drug, even at the lowest tested concentration. This study has shown that using plants for drug biosorption can be an effective standalone or complementary method for water and wastewater treatment. [ABSTRACT FROM AUTHOR]

This study investigates the influence of various parameters on the efficiency of cultivating and preserving Lemna aequinoctialis duckweed samples in vitro, with the aim of minimizing time, labor, and storage expenses. The method addresses the issue of limited space and the risk of sample loss by storing multiple duplicates (more than one tube or flask per sample) in a space-efficient and cost-effective container. Due to the practical implications and capacity to decrease operating expenses, our results are helpful for large-scale implementation. Using a single frond resulted in a longer preservation effect compared to sample densities of three and five fronds. Initial samples can be cultured in nutrient solution with or without sugar, stored in tap water or nutrient solution, kept at a stable temperature of 25 ± 2°C or room temperature. The test tubes with duckweed were not covered, or covered by black paper up to the solution surface or higher. The outcomes demonstrated that all three duckweed samples (HNP_005, HNP_026, and HNP_031), whether grown in SSM or SFM media, were best preserved if the tubes were covered by black paper higher than the solution surface (CH) and can be kept at room temperature for at least 9 mo. [ABSTRACT FROM AUTHOR]

Superior competitors are known to regulate community structure by influencing competitive outcomes between species of inferior competitors with overlapping ecological niches. However, more research is needed to obtain a detailed understanding of the ecological process.We examined how the superior competitor Daphnia magna influenced competition–exclusion between two coexisting Brachionus rotifer species.Brachionus angularis was no longer the superior competitor when D. magna was introduced into the cultured Brachionus calyciflorus + B. angularis system. Small‐sized D. magna (1.6–1.9 mm in body length) mediated population dynamics and facilitated the persistence of the two Brachionus species, while large‐sized D. magna (2.0–2.3 mm in body length) excluded only B. angularis at the high food level (3 × 106 cells/ml Chlorella) or both rotifer species at the low food level (1 × 106 cells/ml Chlorella).These findings indicate that the different body sizes of a superior competitor species can reverse competitive results between inferior competitor species in relation to food abundance.Our results highlight the dynamic nature of populations in multispecies communities and the need to understand species interactions in relation to their environment. [ABSTRACT FROM AUTHOR]

There is still much to learn with respect to the potential for microplastics (MPs) to interact with environmental toxins and biota. In the present study, we investigated the effect of MPs on the toxicity of copper (Cu) to rice seeds (Oryza sativa L.). The 7‐day median effective concentration (EC50) value of MPs on rice seed germination was 864 mg/L (95% confidence interval [CI] 839 to 897 mg/L). We found that MPs slightly reduced Cu toxicity to rice seeds. The 7‐day EC50 of Cu on rice seed germination increased from 7.29 mg/L (95% CI 7.10–7.52 mg/L) to 7.93 mg/L (95% CI 7.58–8.08 mg/L) in the presence of 20 mg/L MPs. We examined this toxicity reduction phenomenon by investigating the role of MPs in the process of Cu transport, Cu accumulation, and metabolic responses. Further investigation found that the MPs used in the present study hardly adsorbed Cu, but these MPs accumulated on the coats of rice seeds and significantly reduced Cu accumulation in rice seedlings. When Cu concentration was 10 mg/L, the presence of MPs reduced the accumulation of Cu in rice seedlings by 34%. We also found that, compared with only Cu present, the addition of MPs resulted in lower reactive oxygen species accumulation and higher catalase activity and glutathione levels in rice seedlings, which also contributed to Cu toxicity reduction. Collectively, the present study shows that polystyrene MPs have the potential to form associations with plant structures which can ultimately impact heavy metal bioaccessibility and therefore toxicity. Environ Toxicol Chem 2024;43:1870–1879. © 2024 SETAC [ABSTRACT FROM AUTHOR]

Featured Application: Utilization of Freshwater aquatic plants' bioactives for functional foods, cosmetic and pharmaceutical applications with anti-inflammatory, antithrombotic and antioxidant health promoting properties. Despite significant progress, certain inflammation related to chronic disorders, including cardiovascular diseases (CVD) and cancer, still present high mortality rates. Thus, further study is needed to address such pathologies more appropriately. Apart from classic therapeutics, natural bioactives with less toxic side effects have gained attention, including those with potential pharmaceutical properties derived from several plants. Within this article, the potential utilization of freshwater aquatic plants as sources of bioactives with antithrombotic, anti-inflammatory and antioxidant properties is outlined. Emphasis is given to a well-established aquatic plant with known but not fully clarified and overviewed bio-functional and pharmaceutical properties, the Chinese lotus (Nelumbo nucifera), as well as to a so far neglected aquatic plant, Lemna minor, which has not yet been thoroughly reviewed for such applications. The latent usually grows naturally in large numbers at the surface of stored water basins of retrieved water from the last stages of wastewater treatment facilities. The continuous growth of this aquatic plant in such conditions further suggests that it can be a sustainable source of natural bioactives, if appropriately valorized, with an economic benefit and in a friendly environmental approach. The abundant content of both freshwater aquatic plants in bioactive components with potent antioxidant, anti-inflammatory and antithrombotic activities is thoroughly outlined, while their applications as functional ingredients in several functional products (functional foods, cosmetics and pharmaceuticals) are also discussed. The outlined outcomes urge further study of both aquatic plants and especially of Lemna spp. to fully elucidate their potential as alternative sustainable sources of bioactive ingredients for functional foods, supplements, nutraceuticals, nutricosmetics, cosmeceuticals, cosmetics and pharmaceutical products with health-promoting properties against inflammation and thrombosis related manifestations and their associated chronic disorders. [ABSTRACT FROM AUTHOR]

Fish feed production is fraught with high costs due to the inclusion of expensive fishmeal and animal proteins that can be sourced from aquatic macrophytes. Limited attempts have been made on use of the latter for fish feed production. Further, the quality of feed given to fish is known to affect its growth and reproductive performance. Role of feeds containing duckweed (Lemna minor) at 0%‐control feed, 10%, 15%, 20% and 25% inclusion levels on growth and reproductive performance of Oreochromis niloticus of size 18 ± 1 g were evaluated for 12 weeks. The fish were fed twice daily at 10% body weight at 9.00 a.m. and 4.00 p.m. Length–weight measurements were done fortnightly using a measuring board and a weighing balance, respectively. Female mouth‐brooding fish were used to evaluate reproductive performance indicators, namely %: fertilization, hatchability and survivability. Data were subjected to one‐way analysis of variance followed by post hoc and polynomial orthogonal analysis to identify L. minor diets with significant differences (p < 0.05). Fish fed on a diet containing 10% L. minor inclusion showed significantly better growth performance and feed conversion ratio than those fed on the control diet. All L. minor diets gave good fish condition factors above 1.0. Fish fed on a diet containing 10% L. minor and those fed on the control gave reasonably high survival rates of 85.55% and 83.33%, respectively, whereas those fed on 20% L. minor produced the same growth performance as control. Orthogonal polynomial analysis for the final weights across the L. minor diets – 0%–25% – showed a cubic polynomial model (p = 0.000), whereas final lengths portrayed a linear inverse significant relationship (p < 0.05). Inclusion of L. minor in the diets resulted to slightly better fertilization, hatchability and survivability rates at 10%, 20% and 15%, respectively. In conclusion, inclusion of L. minor from 10% to 20% in fish feeds is recommended for enhancing growth and reproductive performance of O. niloticus. [ABSTRACT FROM AUTHOR]

Batch hydrogen gas production by co-fermentation of Lemna minor with glucose and Diospyros kaki peels was investigated. Box-Wilson statistical experiment design was used to configure the experiments. The aim was to determine the most suitable Lemna minor-glucose and Lemna minor-Diospyros kaki peel concentration blends resulting in the most convenient hydrogen production yield and rate. Two sets of experiments were performed. For the first set of experiments, most convenient hydrogen yield (77.34 mL H2/10 mL) and rate (10.82 mL H2/h) were obtained by blending 40 g/L Lemna minor with 21 g/L glucose. Higher glucose concentration than 21 g/L at 40 g/L fixed Lemna minor caused substrate inhibition. For the second set of experiments, blending 40 g/L Lemna minor with 60 g/L Diospyros kaki peels resulted in maximum hydrogen yield and rate of 125.35 mL H2/10 mL and 26.95 mL H2/h, respectively. Increasing the blend concentration of Diospyros kaki peels at fixed Lemna minor concentration did have an increasing effect on hydrogen yield and rate. The total sugar concentration did not exceed 21 g/L within the inspected ranges during the second set of experiments; therefore, 40 g/L Lemna minor was blended with 123 g/L Diospyros kaki peels which provided 21 g/L total sugar, and the maximum hydrogen yield (142.24 mL H2/10 mL) and rate (21.34 mL H2/h) were obtained at this point. Model predictions and experimental results were reasonable. Blending Lemna minor with Diospyros kaki peels resulted in more efficient hydrogen production than blending with glucose. [ABSTRACT FROM AUTHOR]

Duckweeds are a widely distributed and economically important aquatic plant family that have high potential for phytoremediation of polluted water bodies. We collected four ecotypes of the common duckweed Lemna minor from the four corners of Switzerland and assessed how their home versus away environments influenced their growth. Additionally, we investigated their response to a metal pollutant (zinc, Zn) in both their home and away environments. Zn is found in freshwater systems and can become harmful to plants at elevated concentrations. We hypothesized that growing in their home environment would help the plants buffer the negative effect of the metal pollutant. To test this, we measured Lemna growth in a common garden experiment in a glasshouse where the four ecotypes were grown in each of the water environments, as well as in three different concentrations of Zn. To investigate whether interactions between Lemna and its microbial community can enhance or reduce tolerance to heavy metal pollution, we sampled chlorophyll‐a as a proxy for algal biomass. Finally, we measured total nitrogen and total organic carbon to describe the abiotic environment in more detail. The four Lemna ecotypes exhibited significantly different growth rates across the water treatments. This difference in fitness was matched with DNA sequencing revealing genetic differentiation between the four ecotypes. However, the effect of the water and Zn treatment on Lemna growth was the same for all ecotypes. We did not find evidence for local adaptation; instead, we observed strong plastic responses. Lemna growth rates were higher under higher Zn concentrations. This positive effect of Zn on Lemna growth could be in part due to reduced competition with algae. We conclude that L. minor ecotypes may exhibit large differences in growth rate, but that the species overall has a high Zn tolerance and strong plastic adaptive potential in novel environments. [ABSTRACT FROM AUTHOR]

EFSA was asked by the European Commission to provide scientific assistance with respect to the EFSA scientific opinion on "Safety of Lemna minor and Lemna gibba whole plant material as a novel food (NF) pursuant to Regulation (EU) 2015/2283", which was adopted in 2022. In that Scientific Opinion, the Panel concluded that the NF, considering its proposed uses and the content of manganese as compared to the content of manganese normally present in other leafy vegetables, may be of safety concern and, therefore, the safety of the NF could not be established. In the context of this mandate, EFSA was requested to evaluate whether the additional information provided by the applicant addresses the increase of manganese intake from the NF, which was considered substantial as compared to the background manganese dietary intake. The applicant provided new data showing that by reducing the manganese concentrations in the cultivation medium, the manganese content in Lemna gibba does not exceed the manganese content in spinach. EFSA emphasizes that the rest of the production process should not deviate from what was reported and assessed in the original NF opinion. Data assessed in 2022 along with data provided for the current assessment show that under the same cultivation conditions Lemna gibba and Lemna minor display similar manganese contents. EFSA acknowledges that the composition of the NF should adhere to the specification levels established in 2022. However, regarding manganese, given the contents observed following these latest production processes, EFSA considers that the maximum specification level for manganese in the NF should be set at 6 mg/kg fresh weight. Based on the additional data provided, EFSA concludes that the contents of manganese in the NF have been reduced to levels not exceeding those in other leafy vegetables. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the chemical composition of lesser duckweed (Lemna minor L.) obtained from the natural environment and cultured under laboratory conditions. In the fi rst variant, lesser duckweed was  collected from a natural pond (LDN). Subsequently, the plants were cleaned of other aquatic fl ora and fauna, dried, and ground. In the second variant, lesser  duckweed was cultured in an aquarium (LDC) illuminated from 04:00 to 24:00. The water temperature was 25 °C and the pH was maintained in the range of 6.5–7.3. The content of crude protein, fat, and fi bre was similar in LDN and LDC,  but the proportion of crude ash was higher in LDC. The content of total amino acids was 95.70 and 68.71 g/100 g crude protein in LDC and LDN, respectively. The concentrations of essential amino acids and nonessential amino acids were 43.75 and 51.96 g/100 g crude protein in LDC, respectively, and 32.10 and 36.61 g/100 g crude protein in LDN, respectively. Palmitic and stearic acids were found in higher quantities in LDN than LDC, whereas the oleic acid content was three-fold higher  in LDN compared to LDC. Moreover,  linoleic and α-linolenic  acid concentrations were higher in LDN than LDC. Mineral analysis revealed elevated levels of Ca, Na, and Zn, while P and Mg levels were lower in LDC. Additionally, the levels of δ-, γ-tocopherols and α-tocotrienol were found to be  higher in LDC, while δ- and γ-tocotrienols in LDC were below detectable limits.  So, the  signifi cant  infl uence of growth  conditions on the nutrient  composition  of L. minor was shown. Optimizing growth conditions is pivotal for enhancing lesser duckweed production. It seems that L. minor can be a valuable source of essential nutrients and could serve as a supplementary food source for both domestic animals and humans. Nonetheless, anti-nutritional components, including toxic metals, should be monitored. [ABSTRACT FROM AUTHOR]

Duckweeds, including the common duckweed Lemna minor, are increasingly used to test eco‐evolutionary theories. Yet, despite its popularity and near‐global distribution, the understanding of its population structure (and genetic variation therein) is still limited. It is essential that this is resolved, because of the impact genetic diversity has on experimental responses and scientific understanding. Through whole‐genome sequencing, we assessed the genetic diversity and population genomic structure of 23 natural Lemna spp. populations from their natural range in Switzerland. We used two distinct analytical approaches, a reference‐free kmer approach and the classical reference‐based one. Two genetic clusters were identified across the described species distribution of L. minor, surprisingly corresponding to species‐level divisions. The first cluster contained the targeted L. minor individuals and the second contained individuals from a cryptic species: Lemna japonica. Within the L. minor cluster, we identified a well‐defined population structure with little intra‐population genetic diversity (i.e., within ponds) but high inter‐population diversity (i.e., between ponds). In L. japonica, the population structure was significantly weaker and genetic variation between a subset of populations was as low as within populations. This study revealed that L. japonica is more widespread than previously thought. Our findings signify that thorough genotype‐to‐phenotype analyses are needed in duckweed experimental ecology and evolution. [ABSTRACT FROM AUTHOR]

The accumulation of arsenic (As) in rice (Oryza sativa L.) grain poses a significant health concern in Bangladesh. To address this, we investigated the efficacy of various organic amendments and phytoremediation techniques in reducing As buildup in O. sativa. We evaluated the impact of five doses of biochar (BC; BC0.1: 0.1%, BC0.28: 0.28%, BC0.55: 0.55%, BC0.82: 0.82% and BC1.0: 1.0%, w/w), vermicompost (VC; VC1.0: 1.0%, VC1.8: 1.8%, VC3.0: 3.0%, VC4.2: 4.2% and VC5.0: 5.0%, w/w), and floating duckweed (DW; DW100: 100, DW160: 160, DW250: 250, DW340: 340 and DW400: 400 g m− 2) on O. sativa cultivated in As-contaminated soil. Employing a three-factor five-level central composite design and response surface methodology (RSM), we optimized the application rates of BC-VC-DW. Our findings revealed that As contamination in the soil negatively impacted O. sativa growth. However, the addition of BC, VC, and DW significantly enhanced plant morphological parameters, SPAD value, and grain yield per pot. Notably, a combination of moderate BC-DW and high VC (BC0.55VC5DW250) increased grain yield by 44.4% compared to the control (BC0VC0DW0). As contamination increased root, straw, and grain As levels, and oxidative stress in O. sativa leaves. However, treatment BC0.82VC4.2DW340 significantly reduced grain As (G-As) by 56%, leaf hydrogen peroxide by 71%, and malondialdehyde by 50% compared to the control. Lower doses of BC-VC-DW (BC0.28VC1.8DW160) increased antioxidant enzyme activities, while moderate to high doses resulted in a decline in these activities. Bioconcentration and translocation factors below 1 indicated limited As uptake and translocation in plant tissues. Through RSM optimization, we determined that optimal doses of BC (0.76%), VC (4.62%), and DW (290.0 g m− 2) could maximize grain yield (32.96 g pot− 1, 44% higher than control) and minimize G-As content (0.189 mg kg− 1, 54% lower than control). These findings underscore effective strategies for enhancing yield and reducing As accumulation in grains from contaminated areas, thereby ensuring agricultural productivity, human health, and long-term sustainability. Overall, our study contributes to safer food production and improved public health in As-affected regions. [ABSTRACT FROM AUTHOR]

Mosquito-borne diseases pose a global health threat, with pathogens like Malaria, Dengue fever, and others transmitted by mosquitoes. Our study focuses on evaluating the toxicity of genetically engineered mosquito larvicidal algae (Chlamydomonas reinhardtii) to non-target organisms, specifically Zebrafish. We conducted a 90-day experiment, feeding Zebrafish different combinations of larvicidal algae and commercial fish feed. Statistical analysis revealed no significant differences in mortality, allergenicity, or moribundity among groups. Hematology, molecular analysis, and necropsy showed no physiological differences. Our findings indicate that the transgenic algae (TN72.cry11Ba) had no adverse effects on adult Zebrafish or their larvae. This study confirmed the safety of algae on non-target organisms, such as zebrafish. [ABSTRACT FROM AUTHOR]

The Gore Glen pond is located in the forested floodplain of the Gore River, in the Mid-Lothian region near Edinburgh, Scotland. This work has considered in detail the hydrology, hydrochemistry, and biodiversity of the pond together with all their interactions and in addition interactions with the adjacent Gore River. It is important as it is one of few studies considering all these issues for a pond located in a riverine floodplain. This work shows the pond is connected to the Gore River for discharge events in the river larger than a 1 in 5-year return period. For these events, the pond acts as an online storage feature and will attenuate the flow, thus contributing towards the mitigation of downstream flooding. These large events are also a potential source of the large amount of sediments, as well as adsorbed chemicals, accumulated in the pond. The open water surface of the pond is covered by duckweed, Lemna minor, for most of the year, and that has profound implications for the hydrobiological community and biogeochemical cycling. The system is characterised by nutrient release from sediments due to the extensive hypolimnion anoxia in the summer/autumn period caused by the decomposition of organic matter. Algae are mostly represented by epiphytic diatoms and the cyanobacterium Microcystis, but their development appears to be constrained by light penetration. The eutrophic conditions are also conducive for the population of Difflugia (Protozoa, Rhizopoda). This work improves our understanding of the ecological relations of testate amoebae—an important group which has recently been used as biological indicators for the analysis of paleoecological relationships and paleogeographical reconstructions. [ABSTRACT FROM AUTHOR]

Duckweed (Lemnaceae) rises as a crucial model system due to its unique characteristics and wide-ranging utility. The significance of physiological research and phytoremediation highlights the intricate potential of duckweed in the current era of plant biology. Special attention to duckweed has been brought due to its distinctive features of nutrient uptake, ion transport dynamics, detoxification, intricate signaling, and stress tolerance. In addition, duckweed can alleviate environmental pollutants and enhance sustainability by participating in bioremediation processes and wastewater treatment. Furthermore, insights into the genomic complexity of Lemnaceae species and the flourishing field of transgenic development highlight the opportunities for genetic manipulation and biotechnological innovations. Novel methods for the germplasm conservation of duckweed can be adopted to preserve genetic diversity for future research endeavors and breeding programs. This review centers around prospects in duckweed research promoting interdisciplinary collaborations and technological advancements to drive its full potential as a model organism. [ABSTRACT FROM AUTHOR]

Background: Capsicum annuum L. belongs to the family Solanaceae is primarily used as a spicy vegetable and as a minor ingredient in wide variety of cuisines, dishes, spice blends and sauces. The current study was dealt with the comparison of morphology of vegetative and reproductive parts and ethno botanical and pharmacological importance of Capsicum annuum L. var. Annuum and Capsicum annuum L. var. Frutescens. Both are shrubby herbs which have an average height ranging between 60-75 cm. Methods: The study materials (flowers, fruits and seeds) were collected from each ten plants of the two varieties of Capsicum annuum L. (Capsicum annuum L. var. Annuum and Capsicum annuum L. var. Frutescens) based on their fruit setting. Result: The results clearly showed the morphological similarities and differences present in terms of nature and arrangement of leaves, flowers and fruits and a short review of their ethno botanical and pharmacological properties. [ABSTRACT FROM AUTHOR]

When subjected to dietary caloric restriction (CR), individual animals often outlive well‐fed conspecifics. Here, we address whether CR also extends lifespan in plants. Whereas caloric intake in animals comes from ingestion, in plants it derives from photosynthesis. Thus, factors that reduce photosynthesis, such as reduced light intensity, can induce CR. In two lab experiments investigating the aquatic macrophyte Lemna minor, we tracked hundreds of individuals longitudinally, with light intensity—and hence, CR—manipulated using neutral‐density filters. In both experiments, CR dramatically increased lifespan through a process of temporal scaling. Moreover, the magnitude of lifespan extension accorded with the assumptions that (a) light intensity positively relates to photosynthesis following Michaelis–Menten kinetics, and (b) photosynthesis negatively relates to lifespan via a power law. Our results emphasize that CR‐mediated lifespan extension applies to autotrophs as well as heterotrophs, and suggest that variation in light intensity has quantitatively predictable effects on plant aging trajectories. [ABSTRACT FROM AUTHOR]

Ailanthus altissima, an invasive plant species, exhibits pharmacological properties, but also some allergic effects on humans. This study aimed to evaluate the potential toxicity of A. altissima leaves, using a complex approach towards different organisms. The ecotoxic impact of a crude extract was investigated on seeds germination and brine shrimp lethality. Cytotoxicity was studied in vitro using non-target (haemolysis, liposomal model, fibroblast), and target (cancer cells) assays. Leaf extract at 1000 µg/mL significantly inhibited wheat and tomato germination, while no significant effects were found on parsley germination. A slight stimulatory effect on wheat and tomato germination was found at 125 µg/mL. In a brine shrimp-test, the extract showed a low toxicity at 24 h post-exposure (LC50 = 951.04 ± 28.26 μg/mL), the toxic effects increasing with the exposure time and extract concentration. Leaf extract caused low hematotoxicity. The extract was biocompatible with human gingival fibroblasts. No anti-proliferative effect was found within the concentration range of 10–500 µg/mL on malignant melanoma (MeWo) and hepatocellular carcinoma (HepG2). In a liposomal model-test, the extract proved to possess low capability to alter the eukaryotic cell-mimicking membranes within the tested concentration range. Given the low to moderate toxicity on tested organisms/cells, the A. altissima autumn leaves may find useful applications. [ABSTRACT FROM AUTHOR]

Isotope labeling coupled with mass spectrometry imaging (MSI) presents a potent strategy for elucidating the dynamics of metabolism at cellular resolution, yet its application to plant systems is scarce. It has the potential to reveal the spatio-temporal dynamics of lipid biosynthesis during plant development. In this study, we explore its application to galactolipid biosynthesis of an aquatic plant, Lemna minor , with D2O labeling. Specifically, matrix-assisted laser desorption/ionization-MSI data of two major galactolipids in L. minor , monogalactosyldiacylglycerol and digalactosyldiacylglycerol, were studied after growing in 50% D2O media over a 15-day time period. When they were partially labeled after 5 d, three distinct binomial isotopologue distributions were observed corresponding to the labeling of partial structural moieties: galactose only, galactose and a fatty acyl chain and the entire molecule. The temporal change in the relative abundance of these distributions follows the expected linear pathway of galactolipid biosynthesis. Notably, their mass spectrometry images revealed the localization of each isotopologue group to the old parent frond, the intermediate tissues and the newly grown daughter fronds. Besides, two additional labeling experiments, (i) 13CO2 labeling and (ii) backward labeling of completely 50% D2O-labeled L. minor in H2O media, confirm the observations in forward labeling. Furthermore, these experiments unveiled hidden isotopologue distributions indicative of membrane lipid restructuring. This study suggests the potential of isotope labeling using MSI to provide spatio-temporal details in lipid biosynthesis in plant development. [ABSTRACT FROM AUTHOR]

Background and Aims The duckweeds (Lemnaceae) consist of 36 species exhibiting impressive phenotypic variation, including the progressive evolutionary loss of a fundamental plant organ, the root. Loss of roots and reduction of vascular tissues in recently derived taxa occur in concert with genome expansions of ≤14-fold. Given the paired loss of roots and reduction in structural complexity in derived taxa, we focus on the evolution of the ionome (whole-plant elemental contents) in the context of these fundamental changes in body plan. We expect that progressive vestigiality and eventual loss of roots might have both adaptive and maladaptive consequences that are hitherto unknown. Methods We quantified the ionomes of 34 accessions in 21 species across all duckweed genera, spanning 70 Myr in this rapidly cycling plant (doubling times are as rapid as ~24 h). We related both micro- and macroevolutionary ionome contrasts to body plan remodelling and showed nimble microevolutionary shifts in elemental accumulation and exclusion in novel accessions. Key Results We observed a robust directional trend in calcium and magnesium levels, decreasing from the ancestral representative Spirodela genus towards the derived rootless Wolffia , with the latter also accumulating cadmium. We also identified abundant within-species variation and hyperaccumulators of specific elements, with this extensive variation at the fine (as opposed to broad) scale. Conclusions These data underscore the impact of root loss and reveal the very fine scale of microevolutionary variation in hyperaccumulation and exclusion of a wide range of elements. Broadly, they might point to trade-offs not well recognized in ionomes. [ABSTRACT FROM AUTHOR]

Because of their abundance and high emissions rates, small reservoirs (< 0.01 km2) can be important emitters of the greenhouse gases carbon dioxide and methane. However, emissions estimates from small reservoirs have lagged those of larger ones, and efforts to characterize small reservoir emissions have largely overlooked variations in emissions pathways, times, and locations. We intensively sampled four small reservoirs in Georgia, USA, during the summer to quantify the contribution and spatiotemporal variability of different emissions pathways (CO2 and CH4 diffusion, CH4 ebullition). We used these data to evaluate the efficiency and accuracy of different sampling schemes. Every emissions pathway was dominant in one reservoir on one sampling day, and excluding ebullition caused misestimation between −89% and −15% of the total flux. Sampling only once daily caused misestimation between −78% and 45%, but sampling twice or just after dawn (07:00 h) reduced error. Sampling four or fewer locations caused misestimation between −85% and 366%, and our results indicated that 6–20 sampling locations may be needed for reasonable accuracy. The floating aquatic macrophyte Wolffia sp. (duckweed) appeared to exert control over emissions variability, and the consequences of not accounting for variability were greater in a duckweed‐covered reservoir. Our results indicate that sampling only at 10:00 h (modal sampling time of prior efforts) may lead to the erroneous conclusion that reservoirs with high photosynthetic biomass are CO2 sinks rather than sources. Improving estimation accuracy by accounting for within‐reservoir variation in emissions will facilitate more strategic management of these abundant, anthropogenic ecosystems. [ABSTRACT FROM AUTHOR]

Aquatic plants, just like terrestrial plants, are exposed to oxidative stress. However, their responses are still under-researched. In this study, we examined the physiological and antioxidative responses of an aquatic plant, duckweed (Lemna minor L.), to four indole-3-acetic acid (IAA)-degrading and -producing Pseudomonas bacteria (Pseudomonas oryzihabitans D1-104/3, P. putida A3-104/5, P. gessardii C31-106/3 and P. yamanorum C44-104/1) and/or a supraphysiological level of IAA (10 mg L−1). Growth characteristics, total photosynthetic pigment content, histochemical localization of reactive oxygen species and antioxidant enzyme activity (SOD, CAT and POX) were evaluated at two time points, after 3 and 7 days of co-cultivation. Superoxide anion and hydrogen peroxide were produced and accumulated mainly in the roots, daughter fronds and veins of duckweeds. Duckweeds' responses depended on the strain of Pseudomonas, time and exogenous IAA. Co-cultivation of duckweed with bacteria has positive or neutral effects. Exogenous application of IAA had a negative or neutral effect on enzyme activity and other parameters. Co-cultivation with P. gessardii C31-106/3 showed plant-growth-promoting effects on duckweed: increased biomass production, modulation of duckweeds' antioxidant enzymatic activity and reduction in hydrogen peroxide content. This study widens our knowledge of aquatic plants and their response to oxidative stress, supports the hypothesis that plant growth-promoting bacteria (PGPB) induce tolerable levels of oxidative stress in plants and introduces a new PGPB strain, P. gessardii C31-106/3. [ABSTRACT FROM AUTHOR]

Fulvic acids (FA) are environmentally prevalent components of dissolved organic carbon. Little research has evaluated their potential influence on the bioavailability of herbicides to non-target aquatic plants. This study evaluated the potential impacts of FA on the bioavailability of atrazine (ATZ) to the aquatic plant Lemna minor. Plants were exposed to 0, 15, 30, 60, 125, and 750 µg/L ATZ in media containing three FA concentrations (0, 5, and 15 mg/L) in a factorial study under static conditions. Fronds were counted after 7- and 14-days exposure and intrinsic growth rates (IGR) and total frond yields were calculated for analysis. Atrazine NOAECs and LOAECs within each FA treatment series (0, 5, or 15 mg/L) were identified and EC50s were estimated. NOAEC/LOAECs for yield and IGR were 60/125 µg/L except for yield in the 0 mg/L-FA series (30/60) and IGR in the 5 mg/L-FA series (30/60). NOAEC/LOAECs were 30/60 µg/L for all treatments and both endpoints after 14 days exposure. EC50s ranged from 88.2 to 106.1 µg/L (frond production 7 DAT), 158.0–186.0 µg/L (IGR, 7 DAT), 74.7–86.3 µg/L (frond production, 14 DAT), and 144.1–151.3 µg/L (IGR, 14 DAT). FA concentrations did not influence the toxicity of ATZ. [ABSTRACT FROM AUTHOR]

In this study, the ecotoxicological effects of a selected OSB material on three model plants (green freshwater algae Desmodesmus subspicatus, duckweed Lemna minor, and seeds of lettuce Lactuca sativa) were tested. A 24 h and 168 h leachate of the same OSB material was prepared. Mg, Si, Ca, K, Fe, Zn, Mn, and Na were found in the samples. Their higher residues were measured in the 168 h leachate. Biogenic elements (N, P, C) were not detected. The acute effect was relatively slow (for algae up to 26%, for duckweed up to 20%, and for lettuce seeds with stimulation up to 37%). Prolongation of the leaching time did not show any effect on the results of the plant tests. Acute toxicity for the three plant species used was slow. [ABSTRACT FROM AUTHOR]

One of the primary sustainability challenges in aquaculture is replacing fish meal with plant‐based ingredients in aquafeeds. Plants are not optimal due to low protein content and antinutritional factors which can cause gut dysbiosis. Duckweed (Lemnaceae) is a family of aquatic plants with high protein content and has been used successfully for various types of animal feeds. In this systematic review and meta‐analysis of 58 papers, we summarize the extent by which duckweed has been used in fish production including the species of fish tested, the grow‐out stage of fish, and method of application. Duckweed studies spanned a total of 18 species of fish (16 freshwater and two marine) that collectively are valued at 263 billion USD annually, and comprise 28% of total aquaculture production by mass. The average experiment length was 72 days (SD 42), primarily at the fingerling life stage. Duckweed was fed to the fish through live grazing, dried, and pelleted forms with 20% inclusion as the most common formulation. The Lemna spp., dominated by L. minor, L. gibba, and unknown Lemna species, were the most commonly used for feeds. Spirodela polyrhiza was the second most common. Duckweed inclusion levels between 15% and 30% were associated with positive outcomes on fish growth and feed conversion ratio without any negative impact on survival rates. Most duckweed species, especially from Wollfiella have not been tested as a fish feed but should be explored whereas most studies focused on freshwater fishes rather than marine. [ABSTRACT FROM AUTHOR]

Agricultural systems must improve their sustainability and productivity to meet the growing global demand for food. A cost-effective and sustainable way is the development of biostimulants from plants rich in bioactive compounds. This study aimed to test an aqueous extract from Lemna minor L. (duckweed) on tomato plants at different concentrations (LE—0.1, 0.5 and 1.0%—weight/volume, w/v). Photosystem I and II activity, linear electron flow (LEF), electrochemical gradient across the thylakoid membrane (ECSt), shoot biomass production, root phenotyping, pigment and metabolite content were studied. LE improved many of these traits, with LE 0.5% being the most effective dosage. Compared to the untreated samples, LE significantly stimulated photosystems to use light energy while reducing the amount lost as heat (PhiNPQ and NPQt) or potentially toxic to chloroplasts (PhiNO). These results were supported by the improved shoot biomass production (number of leaves and fresh and dry weight) and root traits (number of tips, surface, volume and fresh and dry weight) found for LE-treated samples compared to untreated controls. Finally, the study highlighted that LE increased pigment and flavonoid contents. In conclusion, the research indicates that this species can be an effective and eco-friendly tool to stimulate beneficial responses in tomato. [ABSTRACT FROM AUTHOR]

This study explores the combined toxic effect of Mn(II) and resorcinol (0.01 n and 0.2 n) on duckweed (Lemna minor). During the acute experiments, the plants released electrolytes into the aquatic environment after 30 min of exposure to the toxicants, indicating a disruption of tissue permeability as a test response. The experiments showed that the toxicity of the equinormal mixtures of resorcinol and Mn(II) (0.2 n each) increased relative to their single solutions. This was observed both in the freshly prepared solutions and in the solutions stored for 20 h prior to the experiments. The change in the UV absorption spectra indicates that there was complexation or other interaction between resorcinol and Mn(II) at equinormal concentrations (0.01 n). At the Mn(II) : resorcinol ratio of 1:20 (0.01 n Mn(II) and 0.2 n resorcinol), the toxicity of the system to duckweed decreased compared to the separate effects of these substances. The results obtained highlight the importance of considering the interactions between heavy metals and phenolic compounds when assessing the quality of aquatic environments.

Lemnaceae taxonomy is challenged by the particular morphology of these tiny free-floating angiosperms. Although molecular taxonomy has helped clarify the phylogenetic history of this family, some inconsistency with morphological data leads to frequent misclassifications in the genus Lemna. Recently, the finding that Lemna japonica is an interspecific hybrid between Lemna minor and Lemna turionifera provided a clear explanation for one such taxonomic question. Here we demonstrated that L. minor is also capable of hybridizing with Lemna gibba , generating a cryptic but widespread taxon in the Mediterranean area. The nothotaxon Lemna × mediterranea is described and compared with clones of the putative parental species L. minor and L. gibba. Genetic analysis by nuclear and plastid markers, as well as genome size measurement, revealed that two different cytotypes, diploid and triploid, originated by at least two independent hybridization events. Despite high overall similarity, morphometrical, physiological, and biochemical analyses showed an intermediate position of L. × mediterranea between its parental species in most qualitative and quantitative characters, and also separation of the two hybrid cytotypes by some criteria. These data provide evidence that hybridization and polyploidization, driving forces of terrestrial plant evolution, contribute to duckweed genetic diversity and may have shaped the phylogenetic history of these mainly asexual, aquatic plants. [ABSTRACT FROM AUTHOR]

The impact of fluorine on plants remains poorly understood. We examined duckweed growth in extracts of soil contaminated with fluorine leached from chicken manure. Additionally, fluorine levels were analyzed in fresh manure, outdoor-stored manure, and soil samples at varying distances from the manure pile. Fresh manure contained 37–48 mg F− × kg−1, while soil extracts contained 2.1 to 4.9 mg F− × kg−1. We evaluated the physiological effects of fluorine on duckweed cultured on soil extracts or in 50% Murashige–Skoog (MS) medium supplemented with fluorine concentrations matching those in soil samples (2.1 to 4.9 mg F− × L−1), as well as at 0, 4, and 210 mg × L−1. Duckweed exposed to fluorine displayed similar toxicity symptoms whether in soil extracts or supplemented medium. Fluoride at concentrations of 2.1 to 4.9 mg F− × L−1 reduced the intact chlorophyll content, binding the porphyrin ring at position 32 without affecting Mg2+. This reaction resulted in chlorophyll a absorption peak shifted towards shorter wavelengths and formation of a new band of the F−-chlorophyll a complex at λ = 421 nm. Moreover, plants exposed to low concentrations of fluorine exhibited increased activities of aminolevulinic acid dehydratase and chlorophyllase, whereas the activities of both enzymes sharply declined when the fluoride concentration exceeded 4.9 mg × L−1. Consequently, fluorine damages chlorophyll a, disrupts the activity of chlorophyll-metabolizing enzymes, and diminishes the plant growth rate, even when the effects of these disruptions are too subtle to be discerned by the naked human eye. [ABSTRACT FROM AUTHOR]

Using biomass to develop and obtain environmentally friendly and industrially applicable biomaterials is increasingly attracting global interest. Herein, cellulose nanocrystals (CNCs) and lignin nanoparticles (LNPs) were extracted from Lemna minor L., a freshwater free-floating aquatic species commonly called duckweed. To obtain CNCs and LNPs, two different procedures and biomass treatment processes based on bleaching or on the use of an ionic liquid composed of triethylammonium and sulfuric acid ([TEA][HSO4]), followed by acid hydrolysis, were carried out. Then, the effects of these treatments in terms of the thermal, morphological, and chemical properties of the CNCs and LNPs were assessed. The resulting nanostructured materials were characterized by using Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) spectroscopy, thermo-gravimetric analysis (TGA), and scanning electron microscopy (SEM). The results showed that the two methodologies applied resulted in both CNCs and LNPs. However, the bleaching-based treatment produced CNCs with a rod-like shape, length of 100–300 nm and width in the range of 10–30 nm, and higher purity than those obtained with ILs that were spherical in shape. In contrast, regarding lignin, IL made it possible to obtain spherical nanoparticles, as in the case of the other treatment, but they were characterized by higher purity and thermal stability. In conclusion, this research highlights the possibility of obtaining nanostructured biopolymers from an invasive aquatic species that is largely available in nature and how it is possible, by modifying experimental procedures, to obtain nanomaterials with different morphological, purity, and thermal resistance characteristics. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a prevalent and harmful contaminant that persists in the environment. For phytoremediation, it is important to discover which plants can bioaccumulate meaningful amounts of Hg while also tolerating its toxicity. Additionally, increasing biodiversity could create a more resilient and self-sustaining system for remediation. This study explores whether mixed populations of Lemna minor and Spirodela polyrhiza can better bioaccumulate and tolerate Hg than monocultures. Mono- and mixed cultures of L. minor and S. polyrhiza were grown in mesocosms of 0.5 µg/L or 100 µg/L Hg (HgCl2) spiked water for 96 h. Change in weight of duckweed was used to assess Hg tolerance. Diffusive gradients in thin-films (DGTs) were used as surrogate monitoring devices for bioavailable levels of Hg. For biomass growth, the mixed culture of the L. minor was greater than the monoculture at the high dose. The L. minor accumulated more Hg in the mixed culture at the low dose while the S. polyrhiza was higher in the mixed at the high dose. Hg speciation in water was modeled using Windermere Humic Aqueous Model 7 (WHAM7) to compare the bioavailable species indicated by the DGTs. Potentially due to the controlled conditions, the WHAM7 output of bioavailable Hg was almost 1:1 to that estimated by the DGTs, indicating good predictive capability of geochemical modeling and passive sampler DGT on metal bioavailability. Overall, the mixed cultures statistically performed as well as or better than the monocultures when tolerating and bioaccumulating Hg. However, there needs to be further work to see if the significant differences translate into practical differences worth the extra resources to maintain multiple species. [ABSTRACT FROM AUTHOR]

Duckweed (Lemna minor L.) is a small floating aquatic plant that has an important economic impact in several industrial areas. With its high biomass production, reasonable protein content, and resilience to several climates, it has been attracting increasing interest for potential use in animal and human food systems. Historically consumed in southwest Asia, this duckweed is now gaining attention as a potential novel food in Europe. This manuscript explores the contributions of duckweed to various food and feed industries, including aquaculture and livestock, while also pointing out the incipient research carried out for human consumption. Most importantly, it highlights the potential of Lemna minor as a vegetable for future human consumption whether eaten whole or through extraction of its nutrients. [ABSTRACT FROM AUTHOR]

Introduction: Clonal fragmentation helps to assess clonal plants' growth resilience to human and environmental disturbance. Although clonal integration in epiphytes in tropical rubber plantations is important to understand their role in enhancing biodiversity and ecosystem services, research on this subject is limited. These plantations are typically monospecific economic forests that face increased anthropogenic disturbances. Methods: In this study, we selected the clonal fern Pyrrosia nuda to study its survival status, biomass, maximum quantum yield of photosystem II (Fv/Fm), and frond length in response to the level of clonal fragmentation in a tropical rubber plantation. Results and discussion: The results showed that (1) clonal fragmentation significantly negatively affected the survival rate, biomass, and frond length of clonal plants, but with minimal effects on Fv/Fm at different growth stages; (2) the performance of a ramet (e.g., biomass or frond length) increased with ramet developmental ages and decreased with the number of ramets in a clonal fragment. The age-dependent impacts of clonal fragmentation provide insights into the biodiversity conservation of epiphytes and forest management in man- made plantations. Therefore, to better conserve the biodiversity in tropical forests, especially in environment-friendly rubber plantations, there is a need to reduce anthropogenic disturbances and alleviate the level of fragmentation. [ABSTRACT FROM AUTHOR]

The shifting of tannery industries from Hazaribagh to Savar adjacent to Dhaleshwari River might have inevitable adverse impacts, especially the heavy metal contamination of both terrestrial and aquatic ecosystems. The study was carried out to investigate the concentrations of four heavy metals in the soil, water, and plant samples collected from around Dhaleshwari River adjacent to the Bangladesh Small & Cottage Industries Corporation Tannery Industrial Estate, Dhaka. This study revealed that average concentrations of cadmium and chromium in soil exceeded the maximum permissible limit of World Health Organization (1996) and average concentrations of lead, cadmium, and chromium in water exceeded the maximum permissible limit of World Health Organization (2011) and Environmental Conservation Rules (1997). The average concentrations of lead, cadmium, and chromium in the roots and shoots of both Eichhornia crassipes and Cynodon dactylon exceeded the maximum permissible limit of Food and Agriculture Organization/ World Health Organization (2016). Ecological risk assessment using indices model for soil pollution indicated that soil is mostly contaminated with cadmium and chromium which can pose strong ecological risk Health risk assessment using indices model for water pollution revealed the high degree of contamination and unacceptable non-carcinogenic risk and carcinogenic risk for adults as well as children through ingestion of water. Average bioconcentration factor and bioaccumulation factor were higher in Eichhornia crassipes than Cynodon dactylon for lead, cadmium, and chromium. Average translocation factor was also higher in Eichhornia crassipes for all the metals except cadmium. It is suggested remedial and mitigation measures be instituted to control environmental degradation of the newly established Tannery Industrial Estate. [ABSTRACT FROM AUTHOR]

Ribosomal DNA (rDNA) contains highly conserved, specifically organized sequences encoding ribosomal RNAs (rRNAs) separated by variable nontranscribed intergenic spacers (NTSs) and is abundant in eukaryotic genomes. These characteristics make the rDNA an informative molecular target to study genome organization, molecular evolution, and phylogenetics. In this study, we characterized the 5S rDNA repeats in the greater duckweed Spiroldela polyrhiza, a species known for its small size, rapid growth, highly conserved genome organization, and low mutation rate. Sequence analysis of at least 12 individually cloned PCR fragments containing the 5S rDNA units for each of six ecotypes that originated from Europe (Ukraine) and Asia (China) revealed two distinct types of 5S rDNA repeats containing NTSs of different lengths and nucleotide compositions. The shorter 5S rDNA repeat units had a highly homogeneous 400-bp NTS, with few ecotype-or region-specific singlenucleotide polymorphisms (SNPs). The longer 5S rDNA units had NTSs of 1056-1084 bp with characteristic intra- and inter-genomic variants due to specific SNPs and insertions/deletions of 4-15-bp DNA elements. We also detected significant variability in the ratio of short/long 5S rDNA variants between ecotypes of S. polyrhiza. The contrasting dynamics of the two types of 5S rDNA units, combined with the unusually low repeat copy number (for plants) in S. polyrhiza (46-220 copies per genome), shows that this species could serve as an excellent model for examining the mechanisms of concerted evolution and functional significance of rDNA variability. [ABSTRACT FROM AUTHOR]

• Thirty-three plant species were analysed for mutagenicity and toxicity. • A. villicaulis, G. occidentalis and G. senegalensis were not toxic nor mutagenic. • Three plant combinations were found to be non-toxic in the Brine Shrimp Lethality Assay. • Toxicity was more frequently observed than expected. Medicinal plants play an important role in the primary healthcare of lay people around the world, including the rural community of Maputaland, South Africa. According to an ethnobotanical survey conducted in 2014, the lay people in northern Maputaland use plant species independently and in combination to treat gynaecology and obstetric ailments. These plant species were generally regarded as safe by the lay people except for one plant species, Trichilia dregeana Harv. & Sond. The aim of this study was to investigate the safety of 16 plant combinations using the brine shrimp lethality assay (BSLA) for toxicity and Ames test using S. typhimurium TA98 and TA100 strains for mutagenicity. Toxicity studies on 33 medicinal plant species independently needed to be analysed first in order to make a comparison of combined with single use. The aqueous and organic (1:1 methanol-dichloromethane) extracts were prepared from 51 plant samples (including leaf samples collected as a substitution for the roots). There were three plant species (Acalypha villicaulis Horchst. Ex A.Rich. root , Grewia occidentalis L. root and Gymnosporia senegalensis Loes. leaves) indicated neither toxicity nor mutagenicity when tested at 1 and 5 mg/ml using the BSLA and Ames test, respectively. Hermannia boraginiflora Hook. , Sapium integerrimum (Hochst. ex Krauss) , Scadoxus puniceus (L.) Friis Nordal and Tabernaemontana elegans Stapf demonstrated toxicity even after dilution to the lowest concentration of 0.031 mg/ml. The three plant combinations which were found to be non-toxic in the BSLA (both aqueous and organic extracts) were Euphobia tirucalli L. (root) with Ozoroa engleri R.Fern & A.Fern. (bark), S. puniceus (bulb) and Senecio serratuloides DC. (whole plant); Bridelia cathartica G.Bertol. (root) with Opuntia stricta Haw. (stem) with Searsia nebulosa (Schoenland) Moffett (bark); and B. cathartica (root) with Erythrina humeana Spreng (root). In the Ames test, the plant samples which appeared to be non-mutagenic against both S. typhimurium TA98 and TA100 strains were A. villicaulis root , Cyperus natalensis Hochst. ex Krauss root, Euclea natalensis A.DC. leaves, G. occidentalis root , Ochna natalitia Walp. leaves , S. integerrimum leaves and S. puniceus bulb. This study indicated that medicinal plant species (independently and in combination) may have toxic and/ or mutagenic effects, even without any obvious signs after consumption. More importantly, it was determined that toxicity can be reduced by carefully managing the dose. [ABSTRACT FROM AUTHOR]

The micronutrient Zinc (Zn) is essential for the proper growth and development of crops. Zinc oxide nanoparticles (NPs) and fine particles are presented as an emerging alternative to more traditional fertilizers. In this study, the possible toxic effect of four laboratory-synthesized ZnO NPs and fine particles with different characteristics on tomato seed germination and vigor parameters was examined in comparison to bulk ZnO. Different metal precursors were used for the chemical synthesis of the particles: Zn(NO3)2 and ZnSO4, for particles named NIT-. and SUL-., respectively. In addition, the synthesis process was modified to obtain coated particles (denoted as UW-, NIT-UW and SUL-UW) and washed particles (denoted as W-, NIT-W and SUL-W). These particles were applied at different toxic doses (0, 1.4, 2.8, 5.6 and 11.2 g L−1). The results indicated that although the constant contact time between the ZnO particles did not affect the germination capacity of the seeds, it affected the growth of roots and hypocotyls, with a higher impact on the roots' development. This toxicity was more evident from the lowest particle dose used, although it did not prevent radicle and hypocotyl elongation during the development period studied (14 days). The synthesized coated particles (NIT-UW, SUL-UW) generated high toxicity on radicle and hypocotyl development, and this effect was observed from the first days of contact with the particles. The observed toxic effects on radicle length were minimized by the application of bulk ZnO particles. In the case of hypocotyl growth, these minor toxic effects were observed by using NIT-W particles and bulk ZnO. The possibility of positive effects on seed germination and development (radicle and hypocotyl length) when in continuous contact with ZnO, whether in fine particles, nanoparticles, or bulk sizes, was excluded. Furthermore, no benefits on germination parameters were observed by suppressing the final washing step in the particle's synthesis process, suggesting that particle coating did not provide any advantage for seed germination under these continuous contact conditions. [ABSTRACT FROM AUTHOR]

Sweetpotato (Ipomoea batatas L.) was known as a minor root crop in Ghana. Starting in 2010, the International Potato Center (CIP) and multiple partners implemented orange‐fleshed sweetpotato (OFSP) projects to reposition this crop in Ghana. CIP‐led projects from 2010 to 2021 were identified as Research for Development Initiative projects. These projects consisted of (i) new variety development and commercial seed systems (Sweetpotato Action for Security and Health in Africa: 2009–2019); (ii) OFSP products for business development, breeding‐seed system linkages, strategic awareness for demand creation, sensitization, capacity building, advocacy, and strengthen public‐private partnerships (Jumpstarting OFSP: 2014–2017); (iii) research on shelf‐life and appropriate storage practices (two U.S. Agency for International Development's Office of U.S. Foreign Disaster Assistance: 2013–2015 and 2017–2018); and (iv) innovative on‐farm variety testing using the ClimMob‐CitizenScience method (Triadic Comparison of Technologies– roots, tubers, and bananas scaling: 2020–2021). In November 2020, CIP withdrew from Ghana, and the scaling partner, the Reputed Agriculture 4 Development Foundation, led this project up to the end. Strengthened partnerships have driven the expansion of OFSP into value chains. Key partners driving changes were private sector producers and processors, small‐holder farmers, Council for Scientific and Industrial Research institutes, universities, Women in Agricultural Development, Government Extension, Ghana Health Service, and Ghana School Feeding Program. AGRA OFSP for scaling in Ghana (2021–2022) revealed OFSP notably contributed to food security, health, and wealth. It fits in the Food System and contributes to Food Justice in Ghana. Future scaling will depend on consistent policies and efforts to respond to challenges and opportunities along the value chain for sustainability. Impact pathways of theories of change and scaling helped us understand the scaling progress of OFSP in Ghana. Core Ideas: A series of International Potato Center (CIP)‐led projects in Ghana from 2010 to 2021 led to significant scaling of orange‐fleshed sweetpotato (OFSP).Independent, joint program partners were essential for accelerating the process of scaling.Using theories of change and scaling approaches was useful for guiding and tracking progress.Policy support for OFSP must continue to ensure continued scaling in the livelihood system.OFSP can increasingly contribute to Food Justice in Ghana. [ABSTRACT FROM AUTHOR]

Objective. To evaluate the nutritional composition of duckweed (DW) (Lemna minor) and water hyacinth (WH) (Eichhornia crassipes) and its effect on the apparent digestibility of dry matter (%, ADDM), apparent digestibility of crude protein (%, ADCP) and the apparent digestibility of the crude lipid (%, ADCL) in the nutrition of tilapia (Oreochromis niloticus). Material and methods. The DW and WH were used to formulate nine isoproteic (32.47%), isolipidic (5.46%) and isoenergetic (16.45 MJ kg-1) diets, with three replicates and 15 male tilapia (36.36± 1.16 g) per repetition: 0% (T0); 10% (T10); 15% (T15); 20% (T20) and 25% (T25), respectively random. A principal component analysis (PCA) was applied. Results. The crude protein (%) of the WH and the DW, were 21.72% and 27.37% (p<0.05), respectively. Fish fed with WH and DW, up to 10 and 15% inclusion in the diet, respectively, did not show significant differences (p>0.05) for ADDM. However, for ADCP and ADCL, up to 15 and 20%, respectively, significant differences (p>0.05) were not observed. Conclusions. Water hyacinth and duckweed meals were an alternative vegetable protein source, which can partially replace soybean meal and cornmeal in tilapia diets. The PCA suggests that the control diet, 10% WH, 10-15% DW, showed the best results in terms of the apparent digestibility of the nutrients. [ABSTRACT FROM AUTHOR]

Ecologically safe antifouling solutions have received growing attention since the acknowledgment of the environmental risks of traditional biocides used currently. Given that bacteria constitute the initial stage of the biofouling process, this work aims to evaluate the antifouling potential of aquatic macrophyte extracts in inhibiting biofilm-forming bacteria and to evaluate their ecotoxicological effects on target and nontarget organisms (Thalassiosira pseudonana and Nitokra sp.). For this, the ability of 25 macrophyte extracts to inhibit and eradicate single and multispecies estuarine biofilms was evaluated. The extracts and respective serial dilutions that showed a biofilm inhibitory effect ≥ 60% were evaluated in ecotoxicological assays. Of the 25 extracts, only 6 extracts inhibited the biofilm ≥ 60%. The extracts of Cabomba caroliniana and Schoenoplectus californicus stood out as having a biofilm inhibitory effect ≥ 80% (p < 0.05) for bacterial isolates and ≥ 70% (p < 0.05) for multispecies biofilms. Furthermore, these extracts showed no toxic effects on nontarget organisms. These results demonstrate the biotechnological potential of macrophyte compounds. [ABSTRACT FROM AUTHOR]

This study presents a comprehensive examination of Pinus kesiya var. langbianensis (Pinus kesiya var. langbianensis), the primary resin-extraction tree species in Yunnan Province, China. In this study, we formulated different concentration gradients of 0.25%, 0.5%, 1%, and 2% of diquat solution as tapping stimulant to test the effect of different concentrations on the resin gain rate of Pinus kesiya, and analyzed the relationship between anatomical structure, major chemical composition of turpentine and resin yield by methods such as wood anatomy and chemical composition analysis of turpentine. The primary focus of the investigation was on exploring the interrelationships among resin-tapping stimulants, anatomical structures, turpentine components, and resin yield. Research findings demonstrate a significant enhancement in resin production due to the application of stimulants, with the highest increase rate reaching 55% in a specific group, while others achieved approximately 30% increments. Moreover, measurement data about resin duct dimensions indicate a noteworthy increase in resin duct area for the stimulant-treated group compared to the control group. However, it should be noted that the impact on resin duct area by varying stimulant concentrations was relatively minor. Furthermore, continuous observation of resin extraction from different resin-yield classes of P. kesiya revealed insignificant variation in resin yield over time for the low and moderate resin-yield groups. In contrast, the high resin-yield group exhibited a gradual increase in resin production. Interestingly, the high resin-yield group exhibited the smallest resin duct area, but the highest resin duct density, indicating an interconnectedness of resin duct-related data that influences resin yield. Additionally, correlative investigations between anatomical structures and resin yield demonstrate a positive correlation between resin duct area and resin yield, total resin production, and average resin yield. This underscores the importance of resin duct area as a significant factor in resin production. On the other hand, the influence of stimulant concentrations on the turpentine components was found to be negligible. Overall, the correlation results suggest that turpentine components cannot reliably predict or differentiate between high and low resin-yield trees. This study provides a comprehensive analysis of the interrelationships among stimulants, anatomical structures, and turpentine components, offering a theoretical foundation for the resin extraction and resin processing industries in Yunnan Province. [ABSTRACT FROM AUTHOR]