Plant Lemna Research Articles

Fusion of Mitochondria to 3-D Networks, Autophagy and Increased Organelle Contacts are Important Subcellular Hallmarks during Cold Stress in Plants.

Low temperature stress has a severe impact on the distribution, physiology, and survival of plants in their natural habitats. While numerous studies have focused on the physiological and molecular adjustments to low temperatures, this study provides evidence that cold induced physiological responses coincide with distinct ultrastructural alterations. Three plants from different evolutionary levels and habitats were investigated: The freshwater alga Micrasterias denticulata, the aquatic plant Lemna sp., and the nival plant Ranunculus glacialis. Ultrastructural alterations during low temperature stress were determined by the employment of 2-D transmission electron microscopy and 3-D reconstructions from focused ion beam–scanning electron microscopic series. With decreasing temperatures, increasing numbers of organelle contacts and particularly the fusion of mitochondria to 3-dimensional networks were observed. We assume that the increase or at least maintenance of respiration during low temperature stress is likely to be based on these mitochondrial interconnections. Moreover, it is shown that autophagy and degeneration processes accompany freezing stress in Lemna and R. glacialis. This might be an essential mechanism to recycle damaged cytoplasmic constituents to maintain the cellular metabolism during freezing stress.

Ecotoxic interactions between pharmaceuticals in mixtures: Diclofenac and sulfamethoxazole

The objective of this study was to investigate the impact of two pharmaceuticals, diclofenac and sulfamethoxazole, and their binary mixture on aquatic organisms, marine bacteria Aliivibrio fischeri, crustacean Daphnia magna, and vascular plant Lemna minor. The binary mixture of the drugs showed the highest toxicity towards the model organisms. Diclofenac had an average toxicity which posed a high environmental risk to aquatic organisms, while sulfamethoxazole was characterized by a low toxicity with low environmental risk. The organism most sensitive to diclofenac was A. fischeri (IC50 = 8.72 ± 1.14 mg L−1) and for sulfamethoxazole and the binary mixture, it was L. minor (IC50 = 12.56 ± 4.48 and 4.83 ± 0.43 mg L−1, respectively). The toxicity of the mixture was predicted using the Concentration Addition and Independent Action models, and the results were compared with the experimental data. None of the models suitably predicted the real toxicity of the pharmaceutical mixture. Interactions between the mixture components were confirmed by calculating the mixture toxicity index values which showed that the pharmaceuticals displayed synergistic or partial additive effects which depended on the selected test organism and test duration. When added as a complex matrix to wastewater (at a concentration of 2 mg L−1 each), the pharmaceuticals did not display increased toxicity. This observation confirms that the presence of micro-contaminants in aquatic environments may cause interactions between different compounds, the results of which are difficult to predict and model.

Phosphorus phytoremediation using selected wetland plants in constructed floating mats

Phosphorus (P) overloading in fresh water systems has a detrimental effect by increasing the speed of eutrophication. Phytoremediation is the use of natural plants to remove contaminants from the environment. In the current study, we tested five plants (Pteris vittata, Lemna minor, Rumex orbiculatus, Rumex verticillatus, and Typha × glauca) in the laboratory and field for phosphorus mitigation potential. In the field experiment, both root and shoot phosphorus content were evaluated, and in the laboratory study percent phosphorus removed was calculated. Our research showed in both experiments that T. glauca removed the most phosphorus (p < 0.05). In the field study, shoots of T. glauca removed on average 3.7 g P/plant, while the roots and shoots removed 12.67 g P/plant from water. In the laboratory study, the T. glauca removed 84% of the phosphorus from the water. Rumex verticillatus in both experiments had the next highest phosphorus removal rates (0.46 g P/shoot, 1.93 g P/plant (root + shoot), and 90% removal in the laboratory study). These results show great potential for T. glauca and R. verticillatus in the mitigation of phosphorus from fresh water systems.

Identification of the Mechanism Involved in the Removal Potetial of Textile Pollutants by the Aquatic Plant Lemna gibba L.

Identification of the Mechanism Involved in the Removal Potetial of Textile Pollutants by the Aquatic Plant Lemna gibba L.

Phytoremediation of nutrients from water by aquatic floating duckweed (Lemna minor) in rearing of African cichlid (Labidochromis lividus) fingerlings

Abstract Water treatment, reuse, and reducing the nutrients loading to the aquatic environments are key ways to achieve sustainable aquaculture. The usage of aquatic plants is an effective and environment-friendly method for water treatment. This study was conducted to investigate the nutrient removal efficiency of aquatic plant Lemna minor by static test and flow test using a water recirculation system for rearing of African cichlid (Labidochromis lividus) fingerlings during 7 and 30 days, respectively. The growth performance of fish and water quality parameters were compared between the L. minor and control groups in triplicate. The results of static test showed that L. minor removed the total nitrogen ammonia (TAN) and total phosphorus (TP) by 43.7% and 52.38% after 48 h and 7 days, respectively. The results of flow test revealed that the survival rate (%) and growth performance including final weight, final length, weight gain, specific growth rate (SGR%), body weight increase (BWI%) and daily growth index (DGI) of fish cultured in a water recirculation system containing L. minor as a biofilter were significantly higher than the control (P 3 − ) concentration increased to the maximum level on day 20 and then it decreased significantly on day 30 in the L. minor treatment (P

The importance of the calcium-to-magnesium ratio for phytoremediation of dairy industry wastewater using the aquatic plant Lemna minor L.

Lemnaceae are being exploited to remediate a variety of different wastewaters. Our aim was to remediate dairy processing waste, which is produced in large amounts, and contains valuable plant nutrients, for example, nitrate, ammonium, phosphate and iron. However, initial trials failed to establish the growth of Lemna minor on this medium. A lack of growth can be due to a lack of essential plant nutrients, or the presence of phytotoxic ingredients. In this study we show that not just nutrient concentrations, but also the ratios between them can be important in facilitating growth. Lab-scale experiments in which L. minor were grown on 100 mL of synthetic dairy industry wastewater demonstrated that the skewed Ca:Mg ratio in synthetic wastewater is a key obstacle to good growth. Experiments showed that a ratio which favors magnesium over calcium negatively affects L. minor growth and photosynthetic yield, leading to RGRs as low as 0.05 day−1. A change in this ratio to favor calcium, through the addition of calcium sulfate, leads to RGRs of 0.2–0.3 day−1. Experiments lead us to conclude that a Ca:Mg ratio of 1:1.6 or greater is necessary for L. minor growth, and therefore phytoremediation of dairy industry processing wastewater.

The effect of nanoparticles of biogenic ferrihydrite on the Lemna minor L. growth

The article presents the data of experimental studies to identify the effect of biogenic cobalt-doped ferrihydrite nanoparticles on the growth of a model test plant Lemna minor. The test object was exposed for 7 days in a Steinberg medium with the addition of nanoparticles suspension (1.5 mg/l, 4.5 mg/l, and 15.0 mg/l). The analysis of the experimental data showed a suppressive effect of biogenic cobalt-doped ferrihydrite nanoparticles on the number of fronds and the growth rate of Lemna minor at a concentration of 15.0 mg/l. The indicators of root growth (number, length, weight) were similar to the control ones. The obtained data confirm the available data about the negative impact of elements in the form of nanomaterials at high concentrations and require further studies.

Using collector-drainage water in saline and arid irrigation areas for adaptation to climate change

The paper presents data of scientific research on the conditions of the Bukhara oasis of Uzbekistan reducing the salinity of collector-drainage water through water plants Lemna minor, Azolla caroliniana, Eichhornia crassipes and scientific and practical recommendations for the irrigation of cotton biologically purified collector-drainage waters. A decrease in the salinity of collector-drainage water with a salinity of 3-5 g/l was achieved with the help of aquatic plants Lemna minor and Azolla caroliniana, using them as an additional source of water for irrigation of cotton variety Bukhara-102, a high harvest of raw cotton, as well as saved river water and prevented environmental pollution.

Aquatic Phytotoxicity to Lemna minor of Three Commonly Used Drugs of Addiction in Australia.

The manufacturing and consumption of drugs of addiction has increased globally and their widespread occurrence in the environment is an emerging concern. This study evaluated the phytotoxicity of three compounds: methamphetamine, codeine and morphine; commonly reported in Australian urban water, to the aquatic plant Lemna minor under controlled conditions. L. minor was sensitive to lower drug concentrations when administered in multi-compound mixtures (100-500µgL-1) than when applied individually (range 600-2500µgL-1), while no adverse effects were observed at environmentally-relevant concentrations (1-5µgL-1) detected in wastewater effluent. In conclusion, the results show that the concentrations of these compounds discharged into the environment are unlikely to pose adverse phytotoxic effects. These three compounds are known to be the most stable of their group under such conditions indicating that with this respect it is safe to use recycled water for existing regulated reclaimed purposes including agricultural or parklands irrigation or replenishing surface and groundwater. However, more research on the analysis of methamphetamines and opiates in municipal effluents is needed to reassure the likely environmental hazard of these neuroactive drug classes to aquatic organisms. Given the ever-growing production and aquatic disposal of discharge wastewater globally, this study provides timely and valuable insights into the likely drug-related impacts of effluent disposal on aquatic plants in receiving environments.

Assessment of the effects of metribuzin, glyphosate, and their mixtures on the metabolism of the model plant Lemna minor L. applying metabolomics

Chemical plant protection products (PPPs) is a major group of xenobiotics that are being released in the environment. Although the effects of individual active ingredients (a.i.) on organisms have been studied, information on those of mixtures, is fragmented. Aquatic environments are being polluted by PPPs, posing serious risks for the environment, human, and other organisms. Based on the potential of the model aquatic plant Lemna minor L. in the assessment of PPPs-caused stresses, we have undertaken the task of developing a metabolomics approach for the study of the effects of metribuzin and glyphosate, and their mixtures. Bioassays revealed that metribuzin exhibit higher toxicity than glyphosate and metabolomics highlighted corresponding changes in its metabolome. Treatments had a substantial impact on plants' amino acid pool, resulting in elevated levels of the majority of the identified amino acids. Results indicate that the increased proteolytic activity is a common effect of the a.i. and their mixtures. Additionally, the activation of salicylate-signaling pathways was recorded as a response to the toxicity caused by mixtures. Among the identified metabolites that were discovered as biomarkers were γ-aminobutyric acid (GABA), salicylate, caffeate, α,α-trehalose, and squalene, which play multiple roles in plants' metabolism such as, signaling, antioxidant, and structure protection. No reports exist on the combined effects of PPPs on Lemna and results confirm the applicability of Lemna metabolomics in the study of the combined effects of herbicides and its potential in the monitoring of the environmental health of aquatic environments based on fluctuations of the plant's metabolism.

An exploratory ecotoxicity study of primary microplastics versus aged in natural waters and wastewaters

Current understanding of how environmental aging of microplastics contributes to their ecotoxicity is low. We investigated whether incubation of microplastics in waters with different organic load and toxic potential alters the toxicity of microplastics to crustacean Daphnia magna, fish embryos Danio rerio and plant Lemna minor. Polyethylene primary microplastics; specifically microbeads from facial scrub; were subjected to 3-weeks incubation in low affected spring water, river water, effluent from the municipal wastewater treatment plant (WWTP) and municipal landfill leachate. Primary microplastics had no acute effect on D. magna mobility and D. rerio embryos development. While high organic load wastewaters; WWTP effluent and landfill leachate; showed evident toxicity for D. magna and D. rerio embryos, microplastics aged in these wastewaters had no effect. This suggests that adsorption of pollutants from wastewaters to microplastic particles was not high enough to induce acute toxicity to D. magna and D. rerio. On the contrary, primary microplastics affected the root growth of L. minor. Interestingly, aging of microplastics in low organic-load waters mitigated the toxicity of microplastics for L. minor, while microplastics aged in high-organic load waters had the same adverse effect as primary microplastics. Partly, these effects can be explained by different extent of coating on microplastics in different water samples. This study suggests that aging of microplastics in wastewaters and natural waters did not significantly enhance the toxicity to selected test species, but further studies on plants may be of interest.

Toxicity of atrazine and the products of its homogeneous photocatalytic degradation on the aquatic organisms Lemna minor and Daphnia magna.

Usage of atrazine, a widely used herbicide, is now banned in many countries. Although forbidden to use, significant concentration of this herbicide is still present in the environment. The study focused not only on the toxicity of atrazine itself but also on products of homogeneous photocatalytic degradation. Such degradation was very fast in given conditions (sufficient amount of Fe(III) in the reaction system)-more than 95% of the initial amount of atrazine was eliminated after 30 min of irradiation. The toxicity of atrazine and its photodegradation products were examined on the aquatic plant Lemna minor and microcrustacean Daphnia magna in both acute and chronic tests. While the growth inhibition assay of atrazine for Lemna minor revealed EC50 value of 128.4 μg dm-3, the herbicide did not affect Daphnia in the acute toxicity assay. A degradation product, desethyl-atrazine, has been demonstrated to have a pronounced negative effect on the plant growth. Both atrazine and desethyl-atrazine affect negatively the number of juveniles and number of clutches of Daphnia magna in the chronic toxicity assay. Photocatalytic degradation lowers the negative effect of atrazine in Daphnia magna while photodegradation products still negatively affect Lemna growth.

Iron oxide nanoparticle phytotoxicity to the aquatic plant Lemna minor: effect on reactive oxygen species (ROS) production and chlorophyll a/chlorophyll b ratio.

Although iron oxide occurs naturally in the environment, iron oxide nanoparticles have distinct mobility, reactivity, and toxicity, which can harm the human health and nature. This scenario has motivated the investigation of the toxic effects of iron oxide nanoparticles (akaganeite predominance + hematite) on the aquatic plant Lemna minor. First, nanoparticles were synthesized and characterized; then, different iron oxide NP concentrations were added to Lemna minor culture. After 7days, all the Lemna minor leaves died, irrespective of the added NP concentration. The iron oxide NP impact on the plant was evaluated based on malondialdehyde (MDA) production from thiobarbituric acid reactive substances (TBARS), which was dose-dependent; i.e., lipid peroxidation in the plant increased with rising iron oxide NP concentration. The chlorophyll content decreased at high iron oxide NP concentrations, which disrupted the light absorption mechanism. Fe accumulation in Lemna minor roots also occurred, which can harm nutrient uptake. Therefore, the iron oxide NP toxic impact on plants and related ecosystems requires further studies in order to prevent environmental damage.

Phytotoxicity assessment of isoproturon on growth and physiology of non-targeted aquatic plant Lemna minor L. - A comparison of continuous and pulsed exposure with equivalent time-averaged concentrations

Phenylurea herbicides are often present in the aquatic ecosystems and may be accumulated by the non-targeted organisms and impose a negative effect on the organism and the community. This study aims to investigate and compare the effects of two different isoproturon (IPU) pulse exposure scenarios on the non-targeted aquatic plant Lemna minor with effects observed in the standard test with continuous exposure. The obtained results showed that continuous IPU treatment causes significant reduction of photosynthetic pigment concentration and proteins as well as inhibition of L. minor growth. The activities of CAT, G-POX, and APX were significantly induced to diminish the accumulation of ROS under IPU treatment, but the induction of antioxidant enzymes was not sufficient to protect the plants from herbicide-induced oxidative stress. The growth of L. minor under pulse exposure to IPU recovers fast, but pulse treatment results in significant physiological changes in treated plants. The accumulation of H2O2 and lipid peroxidation products, alongside the reduced concentration of proteins and photosynthetic pigments in pulse treatment after a recovery period, indicates that IPU causes prolonged oxidative stress in L. minor plants. The recovery potential of L. minor plants after treatment with herbicides may have an important role in maintaining the population of essential primary producers in aquatic ecosystems, but IPU-induced physiological changes could potentially have a significant role in modulating the response of the plants to the next exposure event.

Environmental Impact of Concrete and Concrete-Based Construction Waste Leachates

Studies concerning environmental impact of construction materials are very rarely based on experiments performed with real mixed samples and test organisms (ecotoxicological bioassays). In our study, ecotoxicity of two concrete samples from different producers and one concrete-based construction waste in leachate form were assessed. Leachates were treated by various designs, i.e. i) without any treatment, ii) original pH + nutrients addition, iii) pH adjustment to 7.0, and iv) pH adjustment to 7.0 + addition of inorganic nutrients. Ecotoxicological bioassays with freshwater algae Desmodesmus subspicatus, freshwater plant Lemna minor and freshwater invertebrate Daphnia magna were performed. The metal content was determined both in solid samples and leachates. Results showed differences in toxicity level among the concrete sources when original leachates without any treatment were tested. On the contrary, the test design recommended by Czech legislation, i.e. lowering of the pH and addition of nutrients usually significantly decreased the sample toxicity and the potential differences among concrete samples. We suggest that the toxicity of concrete leachates may result not only from the highly alkaline pH but also from the potential persistence of high pH values both within dilution process and time. The higher toxicity was in accordance with higher level of leachate conductivity. Therefore, for the purposes of aquatic ecotoxicity assessment, we recommend either making no pH adjustment or performing the bioassays both with treated and untreated leachates.

Gene coexpression analysis reveals dose-dependent and type-specific networks responding to ionizing radiation in the aquatic model plant Lemna minor using public data

Ionizing radiations (IRs) are widespread damaging stresses to plant growth and development. However, the regulatory networks underlying the mechanisms of responses to IRs remains poorly understood. Here, a set of publicly available transcriptomic data (conducted by Van Hoeck et al. 2015a), in which Lemna minor plants were exposed to a series of doses of gamma, beta and uranium treatments was used to perform gene coexpression network analysis. Overall, the genes involved in DNA synthesis and chromatin structure, light signalling, photosynthesis, and carbohydrate metabolism were commonly responsive to gamma, beta and uranium treatments. Genes related to anthocyanin accumulation and trichome differentiation were specifically downregulated, andgenes related to nitrogen and phosphate nutrition, cell vesicle transport, mitochondrial electron transport and ATP synthesis were specifically upregulated in response to uranium treatment. While genes involved in DNA damage and repair, RNA processing and RNA binding were specifically downregulated and genes involved in calcium signalling, redox and degradation of carbohydrate metabolism were specifically upregulated responding to gamma radiation. These findings revealed both dose-dependent and typespecific networks responding to different IRs in L. minor, and can be served as a useful resource to better understand the mechanisms of responses to different IRs in other plants.

Ecotoxicity risk of presence of two cytostatic drugs: Bleomycin and vincristine and their binary mixture in aquatic environment

Cytostatic drugs have become one of the greatest environmental threats. They occur in surface, ground and even drinking water. Their key emission sources are hospital effluents, municipal wastewater, as well as drug manufacturers and their effluents. These compounds are extremely stable in natural waters and they are not significantly removed during wastewater treatment, because they are resistant to biodegradation. The aim of this work was to establish possible negative effects of chosen cytostatics: bleomycin and vincristine on the three trophic levels of surface waters. A single agent acute toxicity test was conducted on representatives of the producer – an aquatic freshwater plant Lemna minor, the consumer - crustaceans Daphnia magna, and the decomposer - bacteria Pseudomonas putida. Binary mixture tests were performed according to the Concentration Addition, Response Additivity, and Independent Action models. Both substances had a different effect on the tested organisms; bleomycin could be classified as a very toxic, while vincristine as a toxic water pollutant. Half maximal effective concentration (EC50) values designed in the presented single agent acute toxicity studies are < 10 mg/L in all the tests with bleomycin as well as vincristine conducted on L. minor. In tests with vincristine performed on D. magna and P. putida EC50 > 100 mg/L. The highest toxicity is demonstrated by bleomycin towards the aquatic freshwater plant (EC50 = 0.2 mg/L). The binary mixture of the tested chemicals showed antagonistic effects of environmental concern.

Colonization and Competition Dynamics of Plant Growth-Promoting/Inhibiting Bacteria in the Phytosphere of the Duckweed Lemna minor.

Despite the considerable role of aquatic plant-associated bacteria in host plant growth and nutrient cycling in aquatic environments, the mode of their plant colonization has hardly been understood. This study examined the colonization and competition dynamics of a plant growth-promoting bacterium (PGPB) and two plant growth-inhibiting bacteria (PGIB) in the aquatic plant Lemna minor (common duckweed). When inoculated separately to L. minor, each bacterial strain quickly colonized at approximately 106 cells per milligram (plant fresh weight) and kept similar populations throughout the 7-day cultivation time. The results of two-membered co-inoculation assays revealed that the PGPB strain Aquitalea magnusonii H3 consistently competitively excluded the PGIB strain Acinetobacter ursingii M3, and strain H3 co-existed at almost 1:1 proportion with another PGIB strain, Asticcacaulis excentricus M6, regardless of the inoculation ratios (99:1-1:99) and inoculation order. We also found that A. magnusonii H3 exerted its growth-promoting effect over the negative effects of the two PGIB strains even when only a small amount was inoculated, probably due to its excellent competitive colonization ability. These experimental results demonstrate that there is a constant ecological equilibrium state involved in the bacterial colonization of aquatic plants.

PENGARUH PENGGUNAAN TEPUNG Lemna sp. TERFERMENTASI PADA PAKAN BUATAN TERHADAP TINGKAT PEMANFAATAN PAKAN, PERTUMBUHAN DAN KELULUSHIDUPAN BENIH IKAN LELE DUMBO (Clarias gariepinus)

The cost of feed is one of the production costs that account for 65%, so the need for alternative feed ingredients that can reduce feed costs. Lemna plant has good enough nutrition as alternative food such as protein 32,13%, nitrogen extract (BETN) 15,96%, and fat 5,13%, crude fiber 28,58% and ash 18, 20% that can be used as fish feed ingredients.The aim of this study is to determine the effect and the best dose level of fermented lemna flour to the level of feed utilization, growth and survival of dumbo catfish (C. gariepinus).The experimental fish used was juvenile of catfishwith an average individual body weight of 3,43±0,06 g and the density of 1 fish/2 l for 42 days. This experimental applied completely randomized design (CRD), which consisted of 5 treatments and 3 replicates. The treatments were treatment each by an addition of flour lemna fermented 0% (A), 5% (B), 10% (C), 15% (D) and 20% (E) respectively. The results showed that the flour lemna fermented provided significantly effect (P&lt;0,05) on total feed comsumption, feed utilization effeciency), protein efficiency ratio and relative growth rate. However, no significant effects (P&gt;0,05) wereoccured on the values of survival rate. The highest dose of 20% dose of fermented lemon flour resulted in total feed intake of 170.01 ± 9.25 g, feed efficiency of 78.82 ± 4.75%, protein efficiency ratio of 2.49 ± 0.15% and the relative growth rate (of 4.60 ± 0.31% / day, while the optimum dose of fermented lemon flour to total feed consumption, the efficiency of feed utilization protein efficiency ratio and relative growth rate have not found the optimum point because based on orthogonal polynomial test still patterned linear.

Physiological and biochemical effect of silver on the aquatic plant Lemna gibba L.: Evaluation of commercially available product containing colloidal silver

This paper aims to evaluate the effects of a product containing colloidal silver in the aquatic environment, using duckweed Lemna gibba as a model plant. Therefore, growth parameters, photosynthetic pigments content and protein content as physiological indices were evaluated. Changes in the content of non-enzymatic antioxidants and activity of several antioxidant enzymes, alongside with the accumulation of hydrogen peroxide and lipid peroxidation end-products were assessed to explore the potential of colloidal silver to induce oxidative stress. The commercially available colloidal silver product contained a primary soluble form of silver. The treatment with colloidal silver resulted in significant physiological and biochemical changes in L. gibba plants and a consequent reduction of growth. Accumulation of silver caused altered nutrient balance in the plants as well as a significant decrease in photosynthetic pigments content and protein concentration. The antioxidative response of L. gibba plants to treatment with colloidal silver was inadequate to protect the plants from oxidative stress caused by metal accumulation. Silver caused concentration-dependent and time-dependent hydrogen peroxide accumulation as well as the elevation of lipid peroxidation levels in L. gibba plants. The use of commercially available products containing colloidal silver, and consequent accumulation of silver, both ionic and nanoparticle form in the environment, represents a potential source of toxicity to primary producers in the aquatic ecosystem.