Farklı pH Değerlerinin Lemna gibba L. ve Lemna minor L.’de Nikel Alınımı ve Klorofi lMiktarına Etkisi

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URUÇ, Kadriye; YILMAZ, Dilek DEMİREZEN; AKBULUT, Hatice

2008-01-01

In this study, the effect of different pH on the nickel absorbtion capacity and amount of chlorophyll of Lemna minor and Lemna gibba was investigated under laboratory conditions.At high pH value (pH = 7), we observed increasing amount of kla and klb with increasing pH. Additionally, nickel accumulation capacity was signifi cantly reduced at pH 4. It means, nickel absorbtion capacity was stimulated by an decrease in pH value. Furthermore, considerably higher accumulation of nickel were found i...

The potential of Lemna gibba L. and Lemna minor L. to remove Cu, Pb, Zn, and As in gallery water in a mining area in Keban, Turkey.

Science.gov (United States)

Sasmaz, Merve; Arslan Topal, Emine Işıl; Obek, Erdal; Sasmaz, Ahmet

2015-11-01

This study was designed to investigate removal efficiencies of Cu, Pb, Zn, and As in gallery water in a mining area in Keban, Turkey by Lemna gibba L. and Lemna minor L. These plants were placed in the gallery water of Keban Pb-Zn ore deposits and adapted individually fed to the reactors. During the study period (8 days), the plant and water samples were collected daily and the temperature, pH, and electric conductivity of the gallery water were measured daily. The plants were washed, dried, and burned at 300 °C for 24 h in a drying oven. These ash and water samples were analyzed by ICP-MS to determine the amounts of Cu, Pb, Zn, and As. The Cu, Pb, Zn and As concentrations in the gallery water of the study area detected 67, 7.5, 7230, and 96 μg L(-1), respectively. According to the results, the obtained efficiencies in L. minor L. and L. gibba L. are: 87% at day 2 and 36% at day 3 for Cu; 1259% at day 2 and 1015% at day 2 for Pb; 628% at day 3 and 382% at day 3 for Zn; and 7070% at day 3 and 19,709% at day 2 for As, respectively. The present study revealed that both L. minor L. and L. gibba L. had very high potential to remove Cu, Pb, Zn, and As in gallery water contaminated by different ores. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

Accumulation of arsenic in Lemna gibba L. (duckweed) in tailing waters of two abandoned uranium mining sites in Saxony, Germany

International Nuclear Information System (INIS)

Mkandawire, Martin; Dudel, E. Gert

2005-01-01

Accumulation of arsenic in Lemna gibba L. was investigated in tailing waters of abandoned uranium mine sites, following the hypothesis that arsenic poses contamination risks in post uranium mining in Saxony, Germany. Consequently, macrophytes growing in mine tailing waters accumulate high amounts of arsenic, which might be advantageous for biomonitoring arsenic transfer to higher trophic levels, and for phytoremediation. Water and L. gibba sample collected from pond on tailing dumps of abandoned mine sites at Lengenfeld and Neuensalz-Mechelgruen were analysed for arsenic. Laboratory cultures in nutrient solutions modified with six arsenic and three PO 4 3- concentrations were conducted to gain insight into the arsenic-L. gibba interaction. Arsenic accumulation coefficients in L. gibba were 10 times as much as the background concentrations in both tailing waters and nutrient solutions. Arsenic accumulations in L. gibba increased with arsenic concentration in the milieu but they decreased with phosphorus concentration. Significant reductions in arsenic accumulation in L. gibba were observed with the addition of PO 4 3- at all six arsenic test concentrations in laboratory experiments. Plant samples from laboratory trials had on average twofold higher bioaccumulation coefficients than tailing water at similar arsenic concentrations. This would be attributed to strong interaction among chemical components, and competition among ions in natural aquatic environment. The results of the study indicate that L. gibba can be a preliminary bioindicator for arsenic transfer from substrate to plants and might be used to monitor the transfer of arsenic from lower to higher trophic levels in the abandoned mine sites. There is also the potential of using L. gibba L. for arsenic phytoremediation of mine tailing waters because of its high accumulation capacity as demonstrated in this study. Transfer of arsenic contamination transported by accumulations in L. gibba carried with flowing

Application of a new sediment contact test with Myriophyllum aquaticum and of the Aquatic Lemna test to assess the sediment quality of Lake Skadar

Energy Technology Data Exchange (ETDEWEB)

Stesevic, D.; Sundic, D.; Mijovic, S. [Montenegro Univ., Podgorica (ME). Faculty of Sciences; Feiler, U.; Heininger, P. [Federal Institute of Hydrology, Koblenz (Germany); Erdinger, L. [Heidelberg Univ. (Germany). Inst. of Hygiene; Seiler, T.B.; Hollert, H. [Heidelberg Univ. (Germany). Dept. of Zoology; RWTH Aachen (Germany). Inst. fuer Umweltforschung - Biologie V

2007-10-15

Goal, Scope and Background: Situated in the transboundary belt between Montenegro and Albania, the Lake Skadar is the largest freshwater reservoir in Southeastern Europe. Because of the wide range of endemic, rare or endangered plant and animal species it supports, Lake Skadar and its extensive adjacent wetlands are internationally recognised as a site of significance and importance (Ramsar site). Within the last 10 to 20 years, Lake Skadar was exposed to intensive pollution. For the assessment of the ecotoxic load of the sediments sampled in Lake Skadar, a triad approach was recently applied. Overall, a complex spectrum of ecotoxic loads was elucidated. The aim of the present study was to use plant-based bioassays for assessing the sediment quality of Lake Skadar in order to facilitate and complement the triad test battery. The newly developed sediment contact test with Myriophyllum aquaticum and the aquatic growth inhibition test with Lemna minor were applied to native sediments and pore water, respectively, allowing the investigation of different toxicity-effects caused by particle-bound pollutants as well as pollutants in the interstitial water. This investigation is the first application of the novel sediment contact test with Myriophyllum aquaticum to lake sediments. Materials and Methods: Sediment samples were taken from nine selected sites at Lake Skadar and investigated by the sediment contact assay with Myriophyllum aquaticum. The pore water was extracted from these sediment samples to be analysed in the aquatic growth inhibition test with Lemna minor. The results of the sediment contact tests were compared with each other and with those of the aquatic growth inhibition test. Results and Discussion: Both applied macrophyte biotests revealed distinct changes in the growth behaviour of the two macrophytes subsequent to the exposure to the investigated natural sediments of Lake Skadar. The Myriophyllum sediment contact test revealed significant toxicity in

Oxygen and hydrogen isotope fractionation during cellulose metabolism in Lemna gibba L

International Nuclear Information System (INIS)

Yakir, D.; DeNiro, M.J.

1990-01-01

Lemna gibba L. B3 was grown under heterotrophic, photoheterotrophic, and autotrophic conditions in water having a variety of hydrogen and oxygen isotopic compositions. The slopes of the linear regression lines between the isotopic composition of water and leaf cellulose indicated that under the three growth conditions about 40, 70, and 100% of oxygens and carbon-bound hydrogens of cellulose exchanged with those of water prior to cellulose formation. Using the equations of the linear relationships, we estimated the overall fractionation factors between water and the exchanged oxygen and carbon bound-hydrogen of cellulose. At least two very different isotope effects must determine the hydrogen isotopic composition of Lemna cellulose. One reflects the photosynthetic reduction of NADP, while the second reflects exchange reactions that occur subsequent to NADP reduction. Oxygen isotopic composition of cellulose apparently is determined by a single type of exchange reaction with water. Under different growth conditions, variations in metabolic fluxes affect the hydrogen isotopic composition of cellulose by influencing the extent to which the two isotope effects mentioned above are recorded. The oxygen isotopic composition of cellulose is not affected by such changes in growth conditions

Accumulation of arsenic in Lemna gibba L. (duckweed) in tailing waters of two abandoned uranium mining sites in Saxony, Germany

Energy Technology Data Exchange (ETDEWEB)

Mkandawire, Martin; Dudel, E. Gert

2005-01-05

Accumulation of arsenic in Lemna gibba L. was investigated in tailing waters of abandoned uranium mine sites, following the hypothesis that arsenic poses contamination risks in post uranium mining in Saxony, Germany. Consequently, macrophytes growing in mine tailing waters accumulate high amounts of arsenic, which might be advantageous for biomonitoring arsenic transfer to higher trophic levels, and for phytoremediation. Water and L. gibba sample collected from pond on tailing dumps of abandoned mine sites at Lengenfeld and Neuensalz-Mechelgruen were analysed for arsenic. Laboratory cultures in nutrient solutions modified with six arsenic and three PO{sub 4}{sup 3-} concentrations were conducted to gain insight into the arsenic-L. gibba interaction. Arsenic accumulation coefficients in L. gibba were 10 times as much as the background concentrations in both tailing waters and nutrient solutions. Arsenic accumulations in L. gibba increased with arsenic concentration in the milieu but they decreased with phosphorus concentration. Significant reductions in arsenic accumulation in L. gibba were observed with the addition of PO{sub 4}{sup 3-} at all six arsenic test concentrations in laboratory experiments. Plant samples from laboratory trials had on average twofold higher bioaccumulation coefficients than tailing water at similar arsenic concentrations. This would be attributed to strong interaction among chemical components, and competition among ions in natural aquatic environment. The results of the study indicate that L. gibba can be a preliminary bioindicator for arsenic transfer from substrate to plants and might be used to monitor the transfer of arsenic from lower to higher trophic levels in the abandoned mine sites. There is also the potential of using L. gibba L. for arsenic phytoremediation of mine tailing waters because of its high accumulation capacity as demonstrated in this study. Transfer of arsenic contamination transported by accumulations in L. gibba

Spectral Reflectance of Duckweed (Lemna Gibba L.) Fronds Exposed to Ethylene Glycol

Science.gov (United States)

Dong, Weijin; Carter, Gregory A.; Barber, John T.

2001-01-01

When duckweed (Lemna Gibba L.) fronds are exposed to ethylene glycol (EG) anatomy is altered, allowing an increase in water uptake that causes a darkening of frond appearance. Spectroradiometry was used to quantify changes in frond reflectance that occurred throughout the 400-850 nm spectrum under various EG concentrations and exposure times. The threshold concentration of EG at which a reflectance change could be detected was between 35 and 40 mM, approximately the same as by visual observation. EG-induced changes in frond reflectance were maximum at concentrations of 50 mM or greater. Reflectance changes were detectable within 24h of exposure to 100 mM EG,2-3 days prior to changes in frond appearance. The spectroradiometry of duckweed may serve as a rapid and sensitive technique for detection of ecosystem exposure to EG and perhaps other stress agents.

Toxic Effects of Nickel Oxide Bulk and Nanoparticles on the Aquatic Plant Lemna gibba L.

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Abdallah Oukarroum

2015-01-01

Full Text Available The aquatic plant Lemna gibba L. was used to investigate and compare the toxicity induced by 30 nm nickel oxide nanoparticles (NiO-NPs and nickel(II oxide as bulk (NiO-Bulk. Plants were exposed during 24 h to 0–1000 mg/L of NiO-NPs or NiO-Bulk. Analysis of physicochemical characteristics of nanoparticles in solution indicated agglomerations of NiO-NPs in culture medium and a wide size distribution was observed. Both NiO-NPs and NiO-Bulk caused a strong increase in reactive oxygen species (ROS formation, especially at high concentration (1000 mg/L. These results showed a strong evidence of a cellular oxidative stress induction caused by the exposure to NiO. Under this condition, NiO-NPs and NiO-Bulk induced a strong inhibitory effect on the PSII quantum yield, indicating an alteration of the photosynthetic electron transport performance. Under the experimental conditions used, it is clear that the observed toxicity impact was mainly due to NiO particles effect. Therefore, results of this study permitted determining the use of ROS production as an early biomarker of NiO exposure on the aquatic plant model L. gibba used in toxicity testing.

Uptake of acidic and basic sugar derivatives in Lemna gibba G1

International Nuclear Information System (INIS)

Sanz, A.; Ullrich, C.I.

1989-01-01

The uptake of acidic and basic sugar derivatives in Lemna gibba L. was studied. Uronic acids applied to the experimental solution induced a small decrease of the membrane potential. After incubation of the plants in a 0.1 millimolar solution of these substrates, no decrease in the concentration of reducing groups in the external solution was detected. Respiration increased by 31% with 50 millimolar galacturonic acid, whereas no effect was found with the same concentration of glucuronic acid. Glucosamine caused a considerable concentration-dependent membrane depolarization. ( 14 C)glucosamine uptake followed Michaelis-Menten kinetics together with a linear component. Influx of this substrate was inhibited by glucose but the type of competition could not be clearly distinguished. Glucosamine, 50 millimolar, inhibited the respiration rate by 30%. The glucosamine uptake was pH-dependent, with maximum uptake at around pH 7. Lack of enhancement of uptake by low pH as well as the permanent membrane depolarization suggest a uniport mechanism for the charged species of the substrate and an electroneutral diffusion of the uncharged species

Evaluation of the effects of diuron and its derivatives on Lemna gibba using a fluorescence toxicity index.

Science.gov (United States)

Dewez, David; Marchand, Mathieu; Eullaffroy, Philippe; Popovic, Radovan

2002-10-01

The herbicide diuron (DCMU) [3-(3,4-dichlorophenyl)-1,1-dimethylurea] is largely used in agricultural practices which contribute to water pollution in large areas. Its degradation induced by light or microbial activity is known to be a slow process, and may result in the accumulation of DCMU derivatives in the environment. In this report we used the yield of PSII variable fluorescence of Lemna gibba affected by the DCMU derivatives DCPMU [1-(3,4-dichlorophenyl)-3-methylurea], DCPU [1-(3,4-dichlorophenyl)urea], and DCA [3,4-dichloroaniline] to calculate the fluorescence toxicity index. We found the fluorescence toxicity index to be a useful parameter to evaluate the inhibitory effect on PSII electron transport in L. gibba exposed to DCMU and its derivatives. The variations observed for the inhibitory effect between DCMU and its derivatives seem to be caused by the modification of the dimethylurea group within the DCMU molecule. The fluorescence toxicity index demonstrated a strong quantitative dependency between the inhibitory effect of PSII electron transport and pollutant concentrations. We propose the fluorescence toxicity index to be a useful tool for future bioassays in evaluating the quality of water polluted with herbicides that induce an inhibition to PSII photochemistry. Copyright 2002 Wiley Periodicals, Inc.

Characterization of a chlorophyll b-less mutant of Lemna gibba G3

International Nuclear Information System (INIS)

Slovin, J.P.

1987-01-01

Nitrosomethylurea mutagenesis of whole plants of duckweed, Lemna gibba G3, produced many plants with various types of obvious pigment abnormalities. One such plant is yellow-green and has a chlorophyll a/b ratio of 8. Spectra from plants grown in white light show a prominent absorption peak at 472 nm, that is not present in spectra from wild type plants. This peak is present, however, when wild type plants are grown under red light conditions. B-less plants accumulate some chlorophyll b under some light conditions and depending on the age of the plants. SDS-PAGE of proteins in thylakoid membranes and in a soluble fraction show that the only obvious band missing corresponds to the LHCP. Preliminary data from 35 S methionine in vivo labeling indicate that there is some LHCP being synthesized in these plant, however the identity of the labeled bands is only now being established using antibodies, and the amount of labeled material does not appear to be the same as in the wild type. The author is currently doing the genetics on this variant and are interested in determining whether the b-less phenotype results from a mutation involving synthesis of the LHCP

Inhibition of flowering in the long-day plant Lemna gibba G3 by Hutner's medium and its reversal by salicyclic acid

Energy Technology Data Exchange (ETDEWEB)

Tanaka, O [Smithsonian Institution Radiation Biology Lab., Rockville, MD; Cleland, C F; Hillman, W S

1979-01-01

Flowering in the long-day plant Lemna gibba L., strain G3 is poor or absent in Hutner's medium even under continuous light, an effect generally ascribed to the ammonium content of the medium. However, flowering is also inhibited in ammonium-free modifications of Hutner's medium, particularly in the presence of sucrose, but is restored to high levels by the presence of 10 ..mu..M salicylic acid. These results link two of the least understood chemical effects in Lemnaceae flowering, and they provide a system in which large effects of salicylic acid can be readily obtained.

Increased polycyclic aromatic hydrocarbon toxicity following their photomodification in natural sunlight: impacts on the duckweed Lemna gibba L. G-3

International Nuclear Information System (INIS)

Huang, X.D.; Dixon, D.G.; Greenberg, B.M.

1995-01-01

The authors previously demonstrated that simulated solar radiation (SSR), with a fluence rate of only 40 mumol m -2 sec -1 , increased polycyclic aromatic hydrocarbon (PAH) toxicity to the duckweed Lemna gibba and that PAHs photomodified in SSR (generally oxygenation of the ring system) are more toxic than the parent compounds (Huang et al., Environ. Toxicol. Chem., 1993, 12, 1067-1077). It is not known, however, to what extent toxicity of PAHs can increase due to photomodification. Thus, natural sunlight, which has a high fluence rate (approximately 2000 mumol m -2 sec -1 ), was used to photomodify anthracene, benzo[a]pyrene, fluoranthene, phenanthrene, and pyrene. Toxicity was based on growth inhibition of L. gibba, measured as the rate of production of new leaves over an 8-day period. Initially, the toxicity of the PAHs applied in intact form was probed, with the compounds demonstrating greater toxicity in sunlight than in SSR. Next the PAHs were photomodified in sunlight prior to incubation with the plants. The half-lives of the PAHs in sunlight ranged from 12 min to 30 hr. Although most of the products of PAH photomodification are not yet identified, the degree that PAH toxicity increased following photomodification in sunlight could still be probed. The mixtures of photomodified chemicals that were derived from each PAH in sunlight were applied of L. gibba and growth inhibition under 100 mumol m -2 sec -1 of SSR was determined. The LC50s for the PAH photoproducts generated in sunlight were an order of magnitude lower than the LC50s for the PAHs applied in intact form. (author)

Photoinduced toxicity of three polycyclic aromatic hydrocarbons (fluoranthene, pyrene, and naphthalene) to the duckweed Lemna gibba L. G-3

International Nuclear Information System (INIS)

Ren, L.; Huang, X.D.; McConkey, B.J.; Dixon, D.G.; Greenberg, B.M.

1994-01-01

The authors recently demonstrated that light dramatically enhances the hazards of three polycyclic aromatic hydrocarbons (PAHs), anthracene, phenanthrene, and benzo[a]pyrene, to the duckweed Lemna gibba L. G-3 (X.-D. Huang, D. G. Dixon, and B. M. Greenberg, 1993, Environ. Toxicol. Chem., 12, 1067-1077). To extend this research, growth and chlorosis were used as end points to assess the photoinduced toxicity of three additional PAHs, fluoranthene, pyrene, and naphthalene, to L. gibba in the presence of simulated solar radiation (a light source with a UV-B: UV-A:visible light ratio equivalent to that of sunlight). The phytotoxicity of these three PAHs was photoactivated, with ultraviolet radiation being the only spectral region that enhanced the harmful effects of the chemicals. Dose-response curves based on chemical concentration and light intensity revealed that the order of phytotoxic strength was fluoranthene > pyrene > naphthalene. To explore whether photomodification (in addition to photosensitization) of fluoranthene, pyrene, and naphthalene could contribute to photoinduced toxicity, the chemicals were irradiated prior to (as opposed to simultaneously with) application to the plans. The rates of photomodification of the three PAHs were rapid enough for the photooxidized compounds to contribute to toxicity, and the photomodified PAHs were more toxic than the parent compounds. As well, toxicity could be correlated to photomodification; impacts increased in parallel with the extent of photomodification

Influence of pH, light cycle, and temperature on ecotoxicity of four sulfonylurea herbicides towards Lemna gibba

DEFF Research Database (Denmark)

Rosenkrantz, Rikke Tjørnhøj; Cedergreen, Nina; Baun, Anders

2013-01-01

test conditions on the toxicity of four sulfonylurea herbicides (SUs). The toxicity of the four SUs towards Lemna gibba was investigated at three pH levels (6, 7.5 and 9), at two temperatures (15 and 24 °C) and two light regimes (continuous and 12:12 h light:dark cycle) The EC50 increased twofold...... conditions e.g. specific temperature, pH, light intensity etc. However, environmental conditions under which the organisms live are rarely identical to the standard conditions. Thus, the ecotoxicity of compounds found in standard test is not only a function of the compounds inherent physico...... to tenfold for the four SUs when pH was increased from 6 to 9. Decreasing the temperature from 24 to 15 °C or introducing a dark:light cycle did not cause any trends in changes in toxicity. The results show that test conditions can have an effect on the toxicity and this should be considered when...

Impacts of UV radiation and photomodification on the toxicity of PAHs to the higher plant Lemna gibba (duckweed)

International Nuclear Information System (INIS)

Huang, X.D.; Dixon, D.G.; Greenberg, B.M.

1993-01-01

The toxicity of polycyclic aromatic hydrocarbons (PAHs) can be enhanced by both biotic and abiotic processes. This is exemplified by light, which, by virtue of the extensive π-orbital systems of PAHs, can be a major factor in PAH toxicity. Light activation of PAHs is known to occur via photosensitization reactions (generation of singlet oxygen and superoxide) and potentially by photomodification of the chemicals (photooxidation and/or photolysis) to more toxic species. To examine the modes of PAH action in the light and determine if the photomodified compounds are hazardous, we investigated the photoinduced toxicity of anthracene, phenanthrene and benzo[a]pyrene to the aquatic higher plant Lemna gibba (a duckweed). Toxicity end points were inhibition of growth and extent of chlorosis. Light did indeed activate the phytotoxicity of PAHs, with UV radiation more effective than visible light. Dose-response curves based on chemical concentration and light intensity revealed the order of phytotoxic strength to be anthracene > phenanthrene > benzo[a]pyrene. To explore whether photomodified PAHs were contributing to toxicity, the chemicals were irradiated before toxicity testing. The rates of photomodification of the three PAHs were rapid (half-lives in hours), and the relative velocities were coincident with the order of toxic strength. Furthermore, the photomodified PAHs were more hazardous to Lemna than the intact compounds. Because interpretations of the potential impacts of PAHs in the environment are based mostly on measurements of the structurally intact chemicals, the severity of PAH hazards is possibly underestimated

Membrane potential and proton cotransport of alanine and phosphate as affected by permeant weak acids in Lemna gibba

International Nuclear Information System (INIS)

Basso, B.; Ullrich-Eberius, C.I.

1987-01-01

The treatment of Lemna gibba plants with the weak acids (trimethylacetic acid and butyric acid), used as tools to decrease intracellular pH, induced a hyperpolarization of membrane potential, dependent on the concentration of the undissociated permeant form of the weak acid and on the value of the resting potential. Measurements were carried out both with high potential and low potential plants and the maximum values of acid induced hyperpolarization were about 35 and 71 millivolts, respectively. Weak acids influenced also the transient light-dark membrane potential changes, typical for photosynthesizing material, suggesting a dependence of these changes on an acidification of cytoplasm. In the presence of the weak acids, the membrane depolarization induced by the cotransport of alanine and phosphate with protons was reduced; the maximum reduction (about 90%) was obtained with alanine during 2 millimolar trimethylacetic acid perfusion at pH 5. A strong inhibition of the uptake rates (up to 48% for [ 14 C]alanine and 68% for 32 P-phosphate) was obtained in the presence of the weak acids, both by decreasing the pH of the medium and by increasing the concentration of the acid. In these experimental conditions, the ATP level and O 2 uptake rates did not change significantly. These results constitute good evidence that H + /solute cotransport in Lemna, already known to be dependent on the electrochemical potential difference for protons, is also strongly regulated by the cytoplasmic pH value

水杨酸诱导膨胀浮萍（Lemna gibba SH0204）开花%Flower-Induction of Lemna gibba SH0204 by Salicylic Acid

Institute of Scientific and Technical Information of China (English)

黄猛; 许亚良; Kanjana Khaeso; 孙雪飘; 张家明

2015-01-01

用水杨酸(SA)诱导膨胀浮萍开花，结果显示，在液体1/2Hoagland培养基中加入适当浓度的SA对开花有显著促进作用， SA浓度为20μmol·L-1时开花率最高，达到39.37%。SA在诱导开花的同时，明显抑制叶状体的生长，在浓度为80μmol·L-1时，叶状体死亡率达到94.38%。此外，本研究尝试在固体1/2Hoagland培养基上诱导膨胀浮萍开花，结果表明，固体培养基比液体培养基更有利于诱导开花， SA浓度为20μmol·L-1时，开花率超过45%，死亡率显著降低。在固体培养基上，方便对开花植株进行跟踪和操作，因此，用固体培养基诱导开花比液体培养基更有应用价值。光学和电子显微镜的观察结果显示，花粉粒呈近圆球形，表面有网状带刺纹饰。%Salicylic acid (SA) was used in the lfower induction of the duckweed Lemna gibba SH0204. Flowers were induced efifciently by suitable concentrations of SA in the liquid 1/2Hoagland medium, and the highest induction rate reached 39.37%at 20μmol·L-1 SA. In the meantime, SA inhibited the growth of L. gibba, and the frond mortality reached 94.38%at 80μmol·L-1 SA. Solid medium was used in the lfower induction of duck-weeds, and was found to be more optimal compared to liquid medium. The highest flower induction rate reached 45%on the solid medium, and the frond mortality decreased signiifcantly. Moreover, the fronds were kept in the original locations on the solid medium, avoiding the damage of the lfowers on the liquid medium by moving around, and providing convenience of tracing or operation with the lfowers. Therefore, solid medium is a practically more useful medium in lfower induction of duckweeds. Electron and light microscopic observation revealed that the pollen grains were spheroid and small, with echinate-reticulate exine.

Stable isotope labeling, in vivo, of D- and L-tryptophan pools in lemna gibba and the low incorporation of label into indole-3-acetic acid

International Nuclear Information System (INIS)

Baldi, B.G.; Maher, B.R.; Slovin, J.P.; Cohen, J.D.

1991-01-01

The authors present evidence that the role of tryptophan and other potential intermediates in the pathways that could lead to indole derivatives needs to be reexamined. Two lines of Lemna gibba were tested for uptake of [ 15 N-indole]-labeled tryptophan isomers and incorporation of that label into free indole-3-acetic acid (IAA). Both lines required levels of L-[ 15 N]tryptophan 2 to 3 orders of magnitude over endogenous levels in order to obtain measurable incorporation of label into IAA. Labeled L-tryptophan was extractable from plant tissue after feeding and showed no measurable isomerization into D-tryptophan. D-[ 15 N]trytophan supplied to Lemna at rates of approximately 400 times excess of endogenous D-tryptophan levels (to yield an isotopic enrichment equal to that which allowed detection of the incorporation of L-tryptophan into IAA), did not result in measurable incorporation of label into free IAA. These results demonstrate that L-tryptophan is a more direct precursor to IAA than the D isomer and suggest (a) that the availability of tryptophan in vivo is not a limiting factor in the biosynthesis of IAA, thus implying that other regulatory mechanisms are in operation and (b) that L-tryptophan also may not be a primary precursor to IAA in plants

Diurnal change of light-dependent uridine incorporation into RNA in a log-day duckweed, Lemna gibba G3

International Nuclear Information System (INIS)

Nakashima, Hideaki

1975-01-01

Light-dependent incorporation during subjective day and night of radioactive uridine into RNA of a long-day duckweed, Lemna gibba G3, was examined. When the dark treatment was started from the subjective night phase, the activity of uridine incorporation dropped approximately by half only after the very subjective night phase had passed or with the commencement of the subsequent subjective day phase. However, when the dark treatment was started from the subjective day phase, the incorporating activity promptly began to decrease and the inhibition increased with the length of the dark period until a final steady level (also at ca. 50% of the initial level) was reached after 24 hr of darkness. These two phases of different light sensitivities recurred daily under control of the physiological clock and the rhythm was reset by a light-on signal. The lowered incorporating activity due to the darkened day phase was recovered completely by a 12-hr or even 15-min white light period perturbing the succeeding night phase. That the incorporation of uridine in every RNA species, especially in chloroplast ribosomal RNA, was lowered by dark treatment of the day and night phases, was disclosed by MAK column chromatography and acrylamide gel electrophoresis. (author)

Comparison of salicylic acid, benzoic acid and p-hydroxybenzoic acid for their ability to induce flowering in Lemna Gibba G3

International Nuclear Information System (INIS)

Cleland, F.C.; Kang, B.G.; Khurana, J.P.

1986-01-01

The long-day plant Lemna gibba G3 fails to flower under continuous light on NH 4 + -free 0.5 H medium. This inhibition is completely reversed by 10 μM salicyclic acid (SA) or 32 μM benzoic acid (BA). By contrast, p-hydroxybenzoic acid (p-OH-BA) has virtually no effect on flowering at levels as high as 320 μM. Uptake rates for the three compounds are comparable. Competition studies using 14 C-SA indicate that, compared to SA, BA is about 10-fold less effective and p-OH-BA is nearly 100-fold less effective in competing against 14 C-SA uptake. Both the effectiveness of SA for inducing flowering and the uptake of 14 C-SA are substantially increased as the pH of the medium is lowered from 8 to 4.5. Under a nitrogen atmosphere the uptake of 14 C-SA is partially inhibited above pH 5. Phosphate metabolism may be important for flowering since increasing the phosphate level in the medium 10-15 fold results in substantial flowering, and suboptimal levels of Sa and phosphate interact synergistically to stimulate flowering. The interaction of phosphate with BA and p-OH-BA will be presented

Haloacetic acids in the aquatic environment. Part I: macrophyte toxicity

International Nuclear Information System (INIS)

Hanson, Mark L.; Solomon, Keith R.

2004-01-01

Haloacetic acids (HAAs) are contaminants of aquatic ecosystems with numerous sources, both anthropogenic and natural. The toxicity of HAAs to aquatic plants is generally uncharacterized. Laboratory tests were conducted with three macrophytes (Lemna gibba, Myriophyllum sibiricum and Myriophyllum spicatum) to assess the toxicity of five HAAs. Myriophyllum spp. has been proposed as required test species for pesticide registration in North America, but few studies have been conducted under standard test conditions. The HAAs in the present experiments were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). MCA was the most toxic to Myriophyllum spp. with EC 50 values ranging from 8 to 12.4 mg/l depending on the endpoint, followed by DCA (EC 50 range 62-722.5 mg/l), TCA (EC 50 range 49.5-1702.6 mg/l), CDFA (EC 50 range 105.3 to >10,000 mg/l) and with TFA (EC 50 range 222.1 to 10,000 mg/l) the least toxic. Generally, L. gibba was less sensitive to HAA toxicity than Myriophyllum spp., with the difference in toxicity between them approximately threefold. The range of toxicity within Myriophyllum spp. was normally less than twofold. Statistically, plant length and node number were the most sensitive endpoints as they had the lowest observed coefficients of variation, but they were not the most sensitive to HAA toxicity. Toxicological sensitivity of endpoints varied depending on the measure of effect chosen and the HAA, with morphological endpoints usually an order of magnitude more sensitive than pigments for all plant species. Overall, mass and root measures tended to be the most sensitive indicators of HAA toxicity. The data from this paper were subsequently used in an ecological risk assessment for HAAs and aquatic plants. The assessment found HAAs to be of low risk to aquatic macrophytes and the results are described in the second manuscript of this series

78 FR 73787 - Chlorsulfuron; Community Right-to-Know Toxic Chemical Release Reporting

Science.gov (United States)

2013-12-09

... identified as the minor metabolic pathway. No additional information on the absorption, distribution... aquatic plants the toxicity of chlorsulfuron is very high. (Ref. 3). Duckweed (Lemna gibba) was the most... (cell density); 120 hr capricornutum). NOEC = 0.0094 mg/L (cell density). Lemna gibba Freshwater...

硝酸铊对浮萍(Lemna gibba L.)的生长抑制及其氧自由基损伤作用%Growth Inhibition of Thallium (Ⅰ)-nitrate on Duckweed (Lemna gibba L.) with Relation to Its Oxidative Stress

Institute of Scientific and Technical Information of China (English)

刘涛; 邓红梅; 王耀龙; 陈永亨; 陈敏婵; 巫贵明; 曾冬媚; 杜建莹; 顾颖诗

2014-01-01

为了探讨硝酸铊(Tl(Ⅰ)-nitrate)对浮萍(Lemna gibba L.)的生长抑制作用及其可能的氧化损伤机制,设置了Tl(Ⅰ)-nitrate的8个处理组(0.005、0.01、0.02、0.04、0.08、0.1、0.5和1.0 mg·L-1)和对照组(0.0 mg·L-1),进行96 h急性毒性实验,测定96 h内超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性及丙二醛含量.结果表明:96 h暴露时间下,浮萍生长受抑制程度与Tl(Ⅰ)浓度之间呈正相关,Tl(Ⅰ)-nitrate对浮萍的96 h EC50为0.076 mg·L-1,NOEC为0.01 mg·L-1.CAT活性随着Tl(Ⅰ)-nitrate浓度升高逐渐降低,在05和1 mg·L-1时,有极显著差异(p＜ 0.01)产生,SOD活性在0.1 mg· L-1时显著升高(＞46％),POD活性和MDA含量在T1(Ⅰ)浓度0.5 mg-L-1时明显上升.当Tl(Ⅰ)-nitrate胁迫超出浮萍抗氧化酶系统清除活性氧的能力时,活性氧积累导致浮萍受到不可逆转的氧化损伤.Tl(Ⅰ)-nitrate对浮萍生长产生明显的抑制作用

Efficient transformation and artificial miRNA gene silencing in Lemna minor.

Science.gov (United States)

Cantó-Pastor, A; Mollá-Morales, A; Ernst, E; Dahl, W; Zhai, J; Yan, Y; Meyers, B C; Shanklin, J; Martienssen, R

2015-01-01

Despite rapid doubling time, simple architecture and ease of metabolic labelling, a lack of genetic tools in the Lemnaceae (duckweed) has impeded the full implementation of this organism as a model for biological research. Here, we present technologies to facilitate high-throughput genetic studies in duckweed. We developed a fast and efficient method for producing Lemna minor stable transgenic fronds via Agrobacterium-mediated transformation and regeneration from tissue culture. Additionally, we engineered an artificial microRNA (amiRNA) gene silencing system. We identified a Lemna gibba endogenous miR166 precursor and used it as a backbone to produce amiRNAs. As a proof of concept we induced the silencing of CH42, a magnesium chelatase subunit, using our amiRNA platform. Expression of CH42 in transgenic L. minor fronds was significantly reduced, which resulted in reduction of chlorophyll pigmentation. The techniques presented here will enable tackling future challenges in the biology and biotechnology of Lemnaceae. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

The effects of a pesticide mixture on aquatic ecosystems differing in trophic status: responses of the macrophyte Myriophyllum spicatum and the periphytic algal community.

Science.gov (United States)

Wendt-Rasch, L; Van den Brink, P J; Crum, S J H; Woin, P

2004-03-01

The effects of a pesticide mixture (asulam, fluazinam, lambda-cyhalothrin, and metamitron) on aquatic ecosystems were investigated in 20 outdoor aquatic microcosms. Ten of the microcosms simulated mesotrophic aquatic ecosystems dominated by submerged macrophytes (Elodea). The others simulated eutrophic ecosystems with a high Lemna surface coverage (Lemna). This paper describes the fate of the chemicals as well as their effects on the growth of Myriophyllum spicatum and the periphytic algal community. In the Elodea-dominated microcosms significant increase in the biomass and alterations of species composition of the periphytic algae were observed, but no effect on M. spicatum growth could be recorded in response to the treatment. The opposite was found in the Lemna-dominated microcosms, in which decreased growth of M. spicatum was observed but no alterations could be found in the periphytic community. In the Elodea-dominated microcosms the species composition of the periphytic algae diverged from that of the control following treatment with 0.5% spray drift emission of the label-recommended rate (5% for lambda-cyhalothrin), while reduced growth of M. spicatum in the Lemna-dominated microcosms was recorded at 2% drift (20% for lambda-cyhalothrin). This study shows that the structure of the ecosystem influences the final effect of pesticide exposure.

Similar stress responses are elicited by copper and ultraviolet radiation in the aquatic plant Lemna gibba: Implication of reactive oxygen species as common signals

International Nuclear Information System (INIS)

Babu, T.S.; Akhtar, T.A.; Lampi, M.A.; Tripuranthakam, S.; Dixon, D.G.; Greenberg, B.M.

2003-01-01

Metals and ultraviolet (UV) radiation are two environmental stressors that can cause damage to plants. These two types of stressors often impact simultaneously on plants and both are known to promote reactive oxygen species (ROS) production. However, little information is available on the potential parallel stress responses elicited by metals and UV radiation. Using the aquatic plant Lemna gibba, we found that copper and simulated solar radiation (SSR, a light source containing photosynthetically active radiation (PAR) and UV radiation) induced similar responses in the plants. Both copper and SSR caused ROS formation. The ROS levels were higher when copper was combined with SSR than when applied with PAR. Higher concentrations of copper plus PAR caused toxicity as monitored by diminished growth and chlorophyll content. This toxicity was more pronounced when copper was combined with SSR. Because the generation of ROS was also higher when copper was combined with SSR, we attributed this enhanced toxicity to elevated levels of ROS. In comparison to PAR-grown plants, SSR treated plants exhibited elevated levels of superoxide dismutase (SOD) and glutathione reductase (GR). These enzyme levels were further elevated under both PAR and SSR when copper was added at concentrations that generated ROS. Interestingly, copper treatment in the absence of SSR (i.e. copper plus PAR) induced synthesis of the same flavonoids as those observed in SSR without copper. Finally, addition of either dimethyl thiourea or GSH (two common ROS scavengers) lowered in vivo ROS production, alleviated toxicity and diminished induction of GR as well as accumulation of UV absorbing compounds. Thus, the potential of ROS being a common signal for acclimation to stress by both copper and UV can be considered. (author)

Investigations on photosynthetic pigments of Lemnaceae, pt. 14: The effect of UV-B radiation on deetiolating and autotrophically growing plants of Lemna gibba L

International Nuclear Information System (INIS)

Wejnar, R.; Döhler, D.

1992-01-01

In deetiolating plants of Lemma gibba L., the biosynthesis of photosynthetically active pigments (chlorophyll a and b, beta-carotene, lutein, violaxanthin and neoxanthin) was reduced by UV-B radiation (2,5 W cnt * m -2 ) in dependence on the exposure time (8-96-h). The biosynthesis of chlorophyll b was more inhibited than that of chlorophyll a, that of the chlorophylls more than that of the carotenoids and that of beta-carotene more than that of the xanthophylls notably lutein. In autotrophic plants. UV-B radiation (42, 72 and 120 h) causes a strong reduction of the pigment content. The alteration of the ratios between the pigments was the same as in deetiolating plants. In deetiolating as well as in autotropically cultivated plants of Lemma gibba, the termination of the UV-B radiation is followed by an approach to the original ratios

Development of a rapid and sensitive battery of bioassays for risk assessment of cyanobacterial microcystin-LR in drinking water of rural water treatment plants, South Africa

CSIR Research Space (South Africa)

Oberholster, Paul J

2009-09-01

Full Text Available minor and Lemna gibba are the most commonly tested species used in numerous studies in first world countries as indi- cator macrophyte species (Marwood et al., 2001). No clear trend exists to the relative sensitivities of the dif- ferent duckweed..., Gu KD, Lam PKA, Yang M, Fong WF (2000). Study on the cytotoxicity of microcystin-LR on cultured cells. Chemosphere, 41: 143-147. Cowgill UM, Milazzo DP, Landenberger BD (1991). The sensitivity of Lemma gibba G-3 and four clones of Lemna minor...

Comparative sensitivity of Selenastrum capricornutum and Lemna minor to sixteen herbicides

Science.gov (United States)

Fairchild, J.F.; Ruessler, D.S.; Haverland, P.S.; Carlson, A.R.

1997-01-01

Aquatic plant toxicity tests are frequently conducted in environmental risk assessments to determine the potential impacts of contaminants on primary producers. An examination of published plant toxicity data demonstrates that wide differences in sensitivity can occur across phylogenetic groups of plants. Yet relatively few studies have been conducted with the specific intent to compare the relative sensitivity of various aquatic plant species to contaminants. We compared the relative sensitivity of the algae Selenestrum capricornutum and the floating vascular plant Lemna minor to 16 herbicides (atrazine, metribuzin, simazine, cyanazine, alachlor, metolachlor, chlorsulfuron, metsulfuron, triallate, EPTC, trifluralin, diquat, paraquat, dicamba, bromoxynil, and 2,4-D). The herbicides studied represented nine chemical classes and several modes of action and were chosen to represent major current uses in the United States. Both plant species were generally sensitive to the triazines (atrazine, metribuzin, simazine, and cyanazine), sulfonureas (metsulfuron and chlorsulfuron), pyridines (diquat and paraquat), dinitroaniline (trifluralin), and acetanilide (alachlor and metolachlor) herbicides. Neither plant species was uniformly more sensitive than the other across the broad range of herbicides tested. Lemna was more sensitive to the sulfonureas (metsulfuron and chlorsulfuron) and the pyridines (diquat and parequat) than Selenastrum. However Selenastrum was more sensitive than Lemna to one of two thiocarbamates (triallate) and one of the triazines (cyanazine). Neither species was sensitive to selective broadleaf herbicides including bromoxynil, EPTC, dicamba, or 2,4-D. Results were not always predictable in spite of obvious differences in herbicide modes of action and plant phylogeny. Major departures in sensitivity of Selenastrum occurred between chemicals within individual classes of the triazine, acetanilide, and thiocarbamate herbicides. Results indicate that neither

History and sensitivity comparison of the Spirodela polyrhiza microbiotest and Lemna toxicity tests

Directory of Open Access Journals (Sweden)

Baudo R.

2015-01-01

Full Text Available The history of toxicity tests with duckweeds shows that these assays with free-floating aquatic angiosperms are gaining increasing attention in ecotoxicological research and applications. Standard tests have been published by national and international organizations, mainly with the test species Lemna minor and Lemna gibba. Besides the former two test species the great duckweed Spirodela polyrhiza is to date also regularly used in duckweed testing. Under unfavorable environmental conditions, the latter species produces dormant stages (turions and this has triggered the attention of two research groups from Belgium and Greece to jointly develop a “stock culture independent” microbiotest with S. polyrhiza. A 72 h new test has been worked out which besides its independence of stock culturing and maintenance of live stocks is very simple and practical to perform, and much less demanding in space and time than the conventional duckweed tests. Extensive International Interlaboratory Comparisons on the S. polyrhiza microbiotest showed its robustness and reliability and triggered the decision to propose this new assay to the ISO for endorsement and publication as a standard toxicity test for duckweeds. Sensitivity comparison of the 72 h S. polyrhiza microbiotest with the 7d L. minor assay for 22 compounds belonging to different groups of chemicals revealed that based on growth as the effect criterion both duckweed assays have a similar sensitivity. Taking into account its multiple advantages and assets, the S. polyrhiza microbiotest is a reliable and attractive alternative to the conventional duckweed tests.

Tissue Characterization of Lemna gibba rbcS Promoter%浮萍rbcS启动子组织特性研究

Institute of Scientific and Technical Information of China (English)

黄凤珍; 李倩; 王友如

2015-01-01

A new rbcS (ribulose-1,5-bisphosphate carboxylase small subunit) promoter with the size of 1 438 bp (named SSU5C promoter) was cloned from Lemna gibba. SSU5C promoter was fused with the GUS reporter gene to construct a plant binary vector (pSSU5C-IGUS), and introduced into duckweed by agrogacterium-mediated trans-formation. The transgenic plantlets were generated. This study was focused on the tissue characterization of SSU5C promoter. GUS staining showed that SSU5C promoter drove GUS to express in the green tissue in leaf, stem and petiole of T1 tobacco, whereas no GUS activity was observed in root. In reproductive organs, the GUS activity was observed in corolla lobes, anther and stigma, no GUS activity was observed in other parts. It was obvious that rbcS promoter can not only express in the green tissue, but also can express in reproductive organs. The results lay a good doundation for the application of SSU5C in plant genetic engineering.%SSU5C启动子(全长1438 bp)是从浮萍基因组中新克隆的一个rb c S (ribulose-1,5-bisphosphate carbo-xylase small subunit)启动子。本研究将 SSU5C 启动子与GUS基因融合，成功构建植物双元表达载p SSU5C-IGUS，并利用农杆菌介导法转化烟草，获得转基因植株，探究SSU5C启动子在烟草中的组织表达特点。GUS检测结果表明：在T1烟草的营养器官中，SSU5C启动子主要驱动GUS基因在烟草叶片和叶柄、茎等绿色组织中表达，而在根部不表达；在生殖器官中，GUS基因主要在花冠裂片以及花药和柱头中表达。本研究首次发现浮萍rb c S启动子不仅在绿色组织中表达，而且在生殖器官中的花冠裂片以及花药和柱头中表达，这一发现可为SSU5C启动子在植物基因工程中的应用奠定基础。

Competition between Free-Floating Plants Is Strongly Driven by Previously Experienced Phosphorus Concentrations in the Water Column.

Science.gov (United States)

Peeters, Edwin T H M; Neefjes, Rozemarijn E M; Zuidam, Bastiaan G van

2016-01-01

Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natans)and the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously experienced phosphorus

Purification and reuse of non-point source wastewater via Myriophyllum-based integrative biotechnology: A review.

Science.gov (United States)

Liu, Feng; Zhang, Shunan; Luo, Pei; Zhuang, Xuliang; Chen, Xiang; Wu, Jinshui

2018-01-01

In this review, the applications of Myriophyllum-based integrative biotechnology to remove common non-point source (NPS) pollutants, such as nitrogen, phosphorus, heavy metals, and organic pollutants (e.g., pesticides and antibiotics) are summarized. The removal of these pollutants via various mechanisms, including uptake by plant and microbial communities in macrophyte-based treatment systems are discussed. This review highlights the potential use of Myriophyllum biomass to produce animal feed, fertilizer, and other valuable by-products, which can yield cost-effective returns and attract more attention to the regulation and recycling of NPS pollutants. In addition, it demonstrates that utilization of Myriophyllum species is a promising and reliable strategy for wastewater treatment. The future development of sustainable Myriophyllum-based treatment systems is discussed from various perspectives. Copyright © 2017 Elsevier Ltd. All rights reserved.

75 FR 11010 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Oregon Chub...

Science.gov (United States)

2010-03-10

... remain at low levels. Comments from States We received several recommendations for minor corrections to... moss), Lemna spp. (duckweed), Myriophyllum spp. (parrot feather), Nuphar spp. (pondlily), and...

The Metagenome of Utricularia gibba's Traps: Into the Microbial Input to a Carnivorous Plant

Science.gov (United States)

Alcaraz, Luis David; Martínez-Sánchez, Shamayim; Torres, Ignacio; Ibarra-Laclette, Enrique; Herrera-Estrella, Luis

2016-01-01

The genome and transcriptome sequences of the aquatic, rootless, and carnivorous plant Utricularia gibba L. (Lentibulariaceae), were recently determined. Traps are necessary for U. gibba because they help the plant to survive in nutrient-deprived environments. The U. gibba's traps (Ugt) are specialized structures that have been proposed to selectively filter microbial inhabitants. To determine whether the traps indeed have a microbiome that differs, in composition or abundance, from the microbiome in the surrounding environment, we used whole-genome shotgun (WGS) metagenomics to describe both the taxonomic and functional diversity of the Ugt microbiome. We collected U. gibba plants from their natural habitat and directly sequenced the metagenome of the Ugt microbiome and its surrounding water. The total predicted number of species in the Ugt was more than 1,100. Using pan-genome fragment recruitment analysis, we were able to identify to the species level of some key Ugt players, such as Pseudomonas monteilii. Functional analysis of the Ugt metagenome suggests that the trap microbiome plays an important role in nutrient scavenging and assimilation while complementing the hydrolytic functions of the plant. PMID:26859489

Changes in antioxidant activity, total phenolic and abscisic acid constituents in the aquatic plants Myriophyllum spicatum L. and Myriophyllum triphyllum Orchard exposed to cadmium.

Science.gov (United States)

Sivaci, Aysel; Sivaci, E Ridvan; Sökmen, Münevver

2007-07-01

Changes in antioxidant activity, total phenolic and abscisic acid (ABA) constituents of Myriophyllum spicatum L. and Myriophyllum triphyllum Orchard, cadmium (Cd) aqueous macrophytes, were investigated exposed to 0, 2, 4, 6, 8, 16 mg l(-1) Cd concentrations. M. triphyllum exhibited strong antioxidant activity but not M. spicatum before and after exposure. Free radical scavenging activity of M. triphyllum was significantly affected from the Cd concentrations and a significant increase was observed at 6 mgl(-1) Cd concentration. Total phenolic constituent and ABA concentration of M. triphyllum is higher than that of M. spicatum with or without heavy metal exposure (P macrophytes that grown in polluted aqueous ecosystem.

马拉硫磷及其水解产物对圆瘤浮萍的生长抑制及氧化损伤作用%Inhibitory Effect of Malathion and Its Hydrolysates on the Growth of Duckweed ( Lemna gibba L. ) and Its Relationship with Oxidative Stress

Institute of Scientific and Technical Information of China (English)

张文萍; 钱双双; 徐吉洋; 吴声敢; 柳新菊; 吕露; 关文碧; 安雪花

2017-01-01

为了探讨马拉硫磷和主要水解产物对圆瘤浮萍的生长抑制作用及可能的氧化损伤机制,采用静态培养法,研究不同浓度的马拉硫磷及其水解产物二甲基二硫代磷酸酯(DMDTP)、二甲基硫代磷酸酯(DMTP)、二甲基磷酸酯(DMP)对圆瘤浮萍生长、叶绿素含量、叶绿体活性、超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性及丙二醛(MDA)含量的影响.结果表明,暴露7 d后,浓度为100 mg a.i.·L-1处理下的浮萍叶状体生长量与空白对照组无显著性差异;DMDTP、DMTP和DMP对圆瘤浮萍叶状体生长量的半数抑制浓度(7 d-IC50)分别为52.9、45.5和98.0 mg a.i.·L-1.随着试验液中DMDTP、DMTP和DMP浓度的升高,圆瘤浮萍叶绿素含量均明显降低,叶绿体活性则分别表现为诱导-抑制、抑制和抑制效应.在DMDTP、DMTP和DMP胁迫下,脂质过氧化产物丙二醛(MDA)含量明显增加;圆瘤浮萍体内的抗氧化酶系统均受到影响.总体表现为随着DMDTP浓度的增加,SOD活性先降低后升高;DMTP和DMP胁迫下,SOD活性呈现先降后升再降的趋势;POD和CAT活性则随3种水解产物浓度的增加呈现先升后降趋势;这表明抗氧化酶系统对外部胁迫的应答很复杂.马拉硫磷对圆瘤浮萍的毒性较小,其水解产物DMDTP、DMTP和DMP均对圆瘤浮萍的生长产生一定的毒性作用.在实际生产中,应多加关注马拉硫磷水解产物对环境生物的风险评估.%In the present study, we aimed to explore toxic effects of malathion, dimethyl dithiophosphate (DMDTP),dimethyl thiophosphate (DMTP) and dimethyl phosphate (DMP) on Lemna gibba L. Toxic effects of malathion, DMDTP, DMTP and DMP on the growth, relative chlorophyll content and chloroplast activity of Lemna gibba L. were assessed using static methods. At a concentration of 100 mg a.i.·L-1 , there was no significant difference be-tween malathion and the blank control, while the 7-day IC50 of DMDTP, DMTP

Competition between Free-Floating Plants Is Strongly Driven by Previously Experienced Phosphorus Concentrations in the Water Column.

Directory of Open Access Journals (Sweden)

Edwin T H M Peeters

Full Text Available Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natansand the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously

Competition between Free-Floating Plants Is Strongly Driven by Previously Experienced Phosphorus Concentrations in the Water Column

Science.gov (United States)

Peeters, Edwin T. H. M.; Neefjes, Rozemarijn E. M.; van Zuidam, Bastiaan G.

2016-01-01

Nutrients can determine the outcome of the competition between different floating plant species. The response of floating plants to current phosphorus levels may be affected by previously experienced phosphorus concentrations because some species have the ability to store excess phosphorus for later use. This might have an impact on their competition. Here, we investigate the effect of previous and actual phosphorus concentrations on the growth rate of free-floating plant species (Azolla filiculoides, Lemna minor/gibba and Ricciocarpus natans)and the effect of phosphorus history on the competition between L. minor/gibba and A. filiculoides and between L. minor/gibba and R. natans. As expected, plant growth was lower when previously kept at low instead of high phosphorus concentrations. Growth of L. minor/gibba and A. filiculoides with a phosphorus rich history was comparable for low and high actual phosphorus concentrations, however, internal phosphorus concentrations were significantly lower with low actual phosphorus concentration. This indicates that both species perform luxury phosphorus uptake. Furthermore, internal P concentration in Azolla and Lemna increased within two weeks after a period of P deficit without a strong increase in growth. A. filiculoides in a mixture with L. minor/gibba grew faster than its monoculture. Morphological differences may explain why A. filiculoides outcompeted L. minor/gibba and these differences may be induced by phosphorus concentrations in the past. Growth of L. minor/gibba was only reduced by the presence of A. filiculoides with a high phosphorus history. Growth of L. minor/gibba and R. natans in mixtures was positively affected only when they had a high phosphorus history themselves and their competitor a low phosphorus history. These observations clearly indicate that phosphorus history of competing plants is important for understanding the outcome of the competition. Therefore, actual and previously experienced phosphorus

Phenolic compounds of ethanol extracts of Lemna minor L., Lemna trisulca L. and Lemna polyrrhiza L. Schleid and their immunomodulating activity

Directory of Open Access Journals (Sweden)

Sergazy M. Adekenov

2017-01-01

Full Text Available The purpose of the study is to determine the composition of the phenolic compounds of ethanol extracts isolated from three species of duckweed: Lemna minor L., Lemna trisulca L. and Lemna polyrrhiza L. (the synonym is Spirodella polyrrhiza Schleid. and to study its effect on immune system activation.Materials and methods. The objects of the study are: air-dried grass samples of Lemna minor L., Lemna trisuica L. and Lemna polyrrhiza L. collected during their growing season in 2010–2011 in low-flow and stagnant ponds of Kozhevnikovsky and Tomsk districts of Tomsk region. Isolation of polyphenolic complexes (PFC was carried out by extraction of air-dried raw material with ethyl alcohol. In qualitative and quantitative analysis of the samples studied the method of reversed-phase high-performance liquid chromatography on an Agilent 1100 Series instrument (USA was used in isocratic mode. In the experiments, 200 male C57BL / 6 and BALB / C mice aged 8–12 weeks were used to determine immunomodulatory activity. Cell proliferation was assessed by a colorimetric method. The absorption of the obtained solutions was measured with a multi-channel spectrophotometer at the wavelength of 540 nm. The determination of antibody-forming cells in the spleen was performed by local hemolysis. The titer of antibodies in serum was evaluated in the hemagglutination reaction. The local hypersensitivity reaction of immediate type was assessed by the author’s modification.Results. For the first time the study of the qualitative composition and quantitative content of PFC of Lemna minor L. (LM , Lemna trisulca L. (LT trisulkas, and Lemna polyrrhiza L. (LP : (4,7 ± 0,4%, (3,3 ± 0,3%, (12,8 ± 0,7% was carried out. The highest content of phenolic acids (10,76% and the sum of flavonoids, isoflavonoids and coumarins (14,7% were found in the LP sample. The content of chlorogenic and 3,5-dihydroxybenzoic acids was 2–9 times higher in LP than in other species of duckweed

Influence of test conditions and exposure duration on the result of ecotoxicological tests

DEFF Research Database (Denmark)

Rosenkrantz, Rikke Tjørnhøj

be calculated from results of ecotoxicological tests performed according to internationally approved guidelines, such as from the Organisation for Economic Co-operation and Development (OECD) or International Standardization Organisation (ISO). Such guidelines were originally developed to enable classification......H and exposure duration on the toxicity recorded in tests using four sulfonylurea herbicides (SUs) and the aquatic macrophyte Lemna gibba as study objects. The study showed that changing the physical and chemical test conditions influenced the toxicity of sulfonylurea herbicides towards L. gibba. Lowering...

Mechanisms of EDDHA effects on the promotion of floral induction in the long-day plant Lemna minor (L.).

Science.gov (United States)

Krajncic, Bozidar; Nemec, Joze

2003-02-01

EDDHA added in an optimal concentration (20.5 mumol.L-1) to a modified Pirson-Seidel nutrient solution induces flowering in some clones of the species Lemna minor, Lemna gibba and Spirodela polyrrhiza, which in the absence of EDDHA in the same nutrient solution do not flower. By adding EDDHA (20.5 mumol.L-1), floral induction under LD conditions is optimally promoted in the long-day (LD) species Lemna minor. After adding EDDHA to the nutrient solution, before floral induction and during flowering, Zn, Mn and Cu content is significantly increased in plants. Zn-EDDHA (0.86 mumol.L-1), Mn-EDDHA (1.51 mumol.L-1) and Cu-EDDHA (0.12 mumol.L-1), when used individually, greatly promote flowering under LD conditions as compared to flowering in the same nutrient solution with an equivalent quantity of Zn, Mn or Cu in the nonchelate form. If, on the other hand, Zn-EDDHA and Mn-EDDHA are added to the nutrient solution together (instead of Zn and Mn in nonchelate form), their effect on the promotion of flowering is less than in the case of their individual use. This shows that there is antagonism between Zn-EDDHA and Mn-EDDHA that is eliminated by adding EDDHA to the nutrient solution. We obtained the highest percentage of flowering plants (i.e. 74%) if we added EDDHA (20.5 mumol.L-1) to the nutrient solution containing Mn, Zn and Cu in chelate form. 74% of flowering plants actually means that flowering was achieved in all physiologically mature plants. Our results show that EDDHA promotes floral induction in Lemna minor under LD conditions, especially through chelating Zn, Mn and Cu, and, in addition, through eliminating the antagonism between Mn and Zn chelates EDDHA. Zn-EDDHA (0.86 mumol.L-1) also promote floral differentiation, especially cell division of microspore mother cells into dyads and those into microspore tetrads, which can be seen in microphotographs. When investigating possible pathways through which Mn-EDDHA, Zn-EDDHA and Cu-EDDHA promote flowering, we studied

Effects of mineral nutrients on ozone susceptibility of Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Craker, L E

1971-01-01

Susceptibility of Lemna minor L. to ozone injury was influenced by the mineral nutrients available to the Lemna plants. Additional nitrogen or additional iron in the nutrient media respectively enhanced or reduced chlorophyll loss of Lemna plants fumigated with ozone. Lemna plants growing on a nutrient medium lacking copper had significantly less injury from ozone fumigation than Lemna plants growing on a complete nutrient medium. There were apparent interactions among phosphorus and potassium nutrient levels in determing the Lemna plant's susceptibility to ozone.

Effects of mineral nutrients on ozone susceptibility of Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Craker, L.E.

1971-01-01

Susceptibility of Lemna minor L. to ozone injury was influenced by the mineral nutrients available to the Lemna plants. Additional nitrogen or additional iron in the nutrient media respectively enhanced or reduced chlorophyll loss of Lemna plants fumigated with ozone. Lemna plants growing on a nutrient medium lacking copper had significantly less injury from ozone fumigation than Lemna plants growing on a complete nutrient medium. There were apparent interactions among phosphorus and potassium nutrient levels in determing the Lemna plant's susceptibility to ozone.

Experimental analysis of the competition between algae and duckweed

NARCIS (Netherlands)

Roijackers, R.M.M.; Szabo, S.; Scheffer, M.

2004-01-01

We performed indoor competition experiments between algae and Lemna gibba L. in order to unravel mechanisms of competition. To separate effects of shading and physical interference from nutrient competition we grew the two groups physically separated while sharing the same water. A multifactorial

Mineralization of 14C-labelled plant material by Porcellio scaber (Crustacea, Isopoda)

International Nuclear Information System (INIS)

Griffiths, B.S.; Wood, S.; Cheshire, M.V.

1989-01-01

Leaf litter was incubated in a mineral soil in the presence or absence of mature Porcellio scaber. The invertebrate caused an increase in the numbers of bacteria, ammonifying bacteria, actinomycetes and protozoa in the soil. The decomposition of 14 C-labelled Lemna gibba was significantly increased by the presence of P. scaber as determined by the total label remaining in the soil and the changes in sugars. 14 C-labelled faeces derived from L. gibba decomposed at a slower rate than the plant tissue from which it originated. (author)

Efecto del fotoperiodo en la remoción de plomo por Lemna gibba L. (Lemnaceae

Directory of Open Access Journals (Sweden)

Guadalupe Miranda

2015-08-01

Full Text Available El plomo llega a las aguas provenientes de las industrias de baterías, soldaduras, pinturas, etc. causando daños a los seres vivos, por lo que es necesario promover el desarrollo de tecnologías que ayuden a mejorar la calidad de los efluentes y que al mismo tiempo sean adecuadas al contexto socioeconómico del país. En este trabajo se plantea el uso de una angiosperma acuática, la especieLemna gibbade la familia Lemnaceae que tiene un crecimiento exponencial y su cultivo es fácil en laboratorio. Para absorber el plomo (PbNO32 se prepararon cinco concentraciones, a nivel de bioensayo en el laboratorio y bajo el efecto de dos diferentes condiciones de fotoperiodo (luz continua y 12 h luz/12 h oscuridad durante cuatro días, ya que a partir de este día libera el Pb al medio. Los resultados indican que en las dos concentraciones de Pb más bajas (30 y 50 mgl-1, el fotoperiodo 12/12 es más favorable para su absorción (9405 µgl-1más y 18,895 µgl-1 más respectivamente mientras que en las tres restantes (100, 200 y 300 mgl-1 lo fue la condición de luz continua. (6600 µgl-1, 1949 µgl-1, 5587 µgl-1 más respectivamente. Los conocimientos que se derivan de este estudio, permiten optimizar el uso deL. gibbaen el tratamiento terciario de aguas residuales.

Uptake and incorporation of labeled tryptophan isomers into IAA in the jsR1 mutant of Lemna gibba

International Nuclear Information System (INIS)

Baldi, B.G.; Maher, B.R.; Cohen, J.D.

1989-01-01

Analyses of the IAA-overproducing mutant of Lemna have been initiated in order to study in vivo biosynthesis of IAA. Using radiolabelled tryptophan isomers prepared from commercial sources of 14 C-D,L tryptophan by chiral separation kinetics of uptake of L and D tryptophan were determined for sterile cultures of individual jsR 1 four-frond colonies. Over a 24 h period, about 50% of the radioactivity from 14 C-L-TRP in media, or about 25% from 14 C-D-TRP, was found in the plant tissue. Maximal rates of uptake were seen in the first six hors for both isomers. Endogenous levels of tryptophan determined in jsR 1 as measures of pool sizes in vivo show 5 to 10 ug/g FW total tryptophan with less than 1% in the D isomer form. Information on uptake and endogenous pool sizes of tryptophan isomers is being used for feeding of stable isotope labeled tryptophan ( 13 C, 14 N) to jsR 1 at physiological levels. Analyses of incorporation of label into IAA using GC-MS and high resolution mass spectrometry are currently underway

Uptake and partitioning of zinc in Lemnaceae.

Science.gov (United States)

Lahive, Elma; O'Callaghan, Michael J A; Jansen, Marcel A K; O'Halloran, John

2011-11-01

Macrophytes provide food and shelter for aquatic invertebrates and fish, while also acting as reservoirs for nutrients and trace elements. Zinc accumulation has been reported for various Lemnaceae species. However, comparative accumulation across species and the link between zinc accumulation and toxicity are poorly understood. Morphological distribution and cellular storage, in either bound or soluble form, are important for zinc tolerance. This study shows differences in the uptake and accumulation of zinc by three duckweed species. Landoltia punctata and Lemna minor generally accumulated more zinc than Lemna gibba. L. minor, but not L. gibba or L. punctata, accumulated greater concentrations of zinc in roots compared to fronds when exposed to high levels of zinc. The proportion of zinc stored in the bound form relative to the soluble-form was higher in L. minor. L. punctata accumulated greater concentrations of zinc in fronds compared to roots and increased the proportion of zinc it stored in the soluble form, when exposed to high zinc levels. L. gibba is the only species that significantly accumulated zinc at low concentrations, and was zinc-sensitive. Overall, internal zinc concentrations showed no consistent correlation with toxic effect. We conclude that relationships between zinc toxicity and uptake and accumulation are species specific reflecting, among others, zinc distribution and storage. Differences in zinc distribution and storage are also likely to have implications for zinc bioavailability and trophic mobility.

Comparative study of compounds of primary exchange duckweed (Lemna minor L., trisulki duckweed (Lemna trisulca L. and spirodela (Spirodella polyrrhiza L. Schleid.

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L. A. Nikiforov

2017-01-01

Full Text Available The purpose of the paper is to study qualitative composition and quantitative content of primary exchange compounds in duckweed (Lemna minor L., trisulki duckweed (Lemna trisulca L. and spirodela (Spirodella polyrrhiza (L. Schleid.Materials and methods. The subject of the study was air-dried samples of grass collected during their 2010- 2011 growing season in low-flow and stagnant water bodies of Kozhevnikovsky and Tomsk districts of the Tomsk region. The concentration of free monosaccharides was determined by direct-phase high-performance liquid chromatography. The concentration of the bound sugars was determined by capillary electrophoresis using Applied Biosystem 273T (Thermophischer Ltd., USA. To obtain data on the qualitative composition and quantitative content of amino acids, the amino acid analyzer Hitachi 835 (Japan was used.Results. It was found out that the least amount of amino acids contained in the water extract from duckweed trifoliate – 96,14 mg, which is 2 times less than in extracts of Lemna minor and Lemna multirooted (205,65 and 208,38 mg, respectively. In duckweed the minimum content of free and bound monosaccharides was determined to be 10,54%, while in the Lemna trifoliate and Lemna multirooted their content was 14,30% and 15,35%, respectively. This study showed the qualitative and quantitative differences of free and bound monosaccharide and amino acid composition between previously mentioned species. 

Potential of macrophyte for removing arsenic from aqueous solution Potencial de remoção de arsênio de solução aquosa por macrofita

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F.P. Guimaraes

2012-12-01

Full Text Available The potential of three aquatic macrophytes, Azoll caroliniana, Salvinia minima and Lemna gibba, was evaluated in this work aimed at selection of plants to be used in remediation of environments contaminated by arsenic (As. The experiments were carried out in a greenhouse during six days in pots containing Hoagland solution (¼ ionic strength at As concentrations of 0.5; 2.5 and 5.0 mg L-1. The three species showed greater As accumulation as the concentration of the metalloid in solution increased. However, a reduction was detected in fresh and dry mass gain when the plants were exposed to high As concentrations. The macrophytes showed differences in efficiency of removal of As in solution. A. caroliniana, S. minima and L. gibba accumulated, on average, 0.130; 0.200; and 1.397 mg mDM-1, respectively, when exposed to 5.0 mg L-1 of As. The macrophytes absorbed a greater quantity of As in solution with low phosphate content. The greater As concentration in L. gibba tissues lowered the chlorophyll and carotenoid contents as shown by the high chlorosis incidence. Lemna gibba also exhibited a decrease in leaf size, with the total chlorophyll and carotenoid synthesis not being affected by As in A. caroliniana. This species exhibited purplish leaves with high concentration of anthocyanin, whose presence suggested association to phosphate deficiency. Marginal necrosis occurred on S. minima floating leaves, with the released daughter-plants not showing any visual symptoms during the treatment. The percentage of As removed from the solution decreased when the plants were exposed to high concentrations of the pollutant. Among the three species studied, only L. gibba could be considered an As hyper-accumulator. The use of this plant species for remediation of aquatic environments was shown to be limited and requires further investigation.O potencial de três macrófitas aquáticas - Azolla caroliniana, Salvinia mínima e Lemna gibba - foi avaliado neste

Cadmium removal by Lemna minor and Spirodela polyrhiza.

Science.gov (United States)

Chaudhuri, Devaleena; Majumder, Arunabha; Misra, Amal K; Bandyopadhyay, Kaushik

2014-01-01

The present study investigates the ability of two genus of duckweed (Lemna minor and Spirodela polyrhiza) to phytoremediate cadmium from aqueous solution. Duckweed was exposed to six different cadmium concentrations, such as, 0.5,1.0,1.5, 2.0, 2.5, and 3.0 mg/L and the experiment was continued for 22 days. Water samples were collected periodically for estimation of residual cadmium content in aqueous solution. At the end of treatment period plant samples were collected and accumulated cadmium content was measured. Cadmium toxicity was observed through relative growth factor and changes in chlorophyll content Experimental results showed that Lemna minor and Spirodela polyrhiza were capable of removing 42-78% and 52-75% cadmium from media depending upon initial cadmium concentrations. Cadmium was removed following pseudo second order kinetic model Maximum cadmium accumulation in Lemna minor was 4734.56 mg/kg at 2 mg/L initial cadmium concentration and 7711.00 mg/kg in Spirodela polyrhiza at 3 mg/L initial cadmium concentration at the end of treatment period. Conversely in both cases maximum bioconcentration factor obtained at lowest initial cadmium concentrations, i.e., 0.5 mg/L, were 3295.61 and 4752.00 for Lemna minor and Spirodela polyrhiza respectively. The present study revealed that both Lemna minor and Spirodela polyrhiza was potential cadmium accumulator.

Cumulative Index to Chemicals and to Common and Scientific Names of Species Listed in Contaminant Hazard Reviews 1 Through 34.

Science.gov (United States)

1999-03-01

Wildlife Research Center- synthesizes ecotoxicological data for selected environmental contaminants, with emphasis on hazards to native species of flora...series-—sponsored by the U.S. Geological Survey Patuxent Wildlife Research Center—synthesizes ecotoxicological data for selected environmental...7 37. Macronectes giganteus: 32 16; 33 26; 34 27. Macrophytes , aquatic, Cabomba spp., Chara sp., Elodea, Lemna, Myriophyllum, Polygonum sp

Control of the Protein Turnover Rates in Lemna minor

Science.gov (United States)

Trewavas, A.

1972-01-01

The control of protein turnover in Lemna minor has been examined using a method described in the previous paper for determining the rate constants of synthesis and degradation of protein. If Lemna is placed on water, there is a reduction in the rate constants of synthesis of protein and an increase (3- to 6-fold) in the rate constant of degradation. The net effect is a loss of protein from the tissue. Omission of nitrate, phosphate, sulfate, magnesium, or calcium results in increases in the rate constant of degradation of protein. An unusual dual effect of benzyladenine on the turnover constants has been observed. Treatment of Lemna grown on sucrose-mineral salts with benzyladenine results in alterations only in the rate constant of synthesis. Treatment of Lemna grown on water with benzyladenine alters only the rate constant of degradation. Abscisic acid on the other hand alters both rate constants of synthesis and degradation of protein together. Inclusion of growth-inhibiting amino acids in the medium results in a reduction in the rate constants of synthesis and increases in the rate constant of degradation of protein. It is concluded that the rate of turnover of protein in Lemna is very dependent on the composition of the growth medium. Conditions which reduce growth rates also reduce the rates of synthesis of protein and increase those of degradation. PMID:16657895

Uso de diferentes herbicidas no controle de Myriophyllum aquaticum Chemical Control of Myriophyllum aquaticum

Directory of Open Access Journals (Sweden)

E. Negrisoli

2003-01-01

Full Text Available Este estudo teve a finalidade de avaliar, em condições de caixa d'água, o controle químico de Myriophyllum aquaticum (pinheiro-d'água, através de herbicidas aplicados em pós-emergência. Os herbicidas e respectivas doses (g ha-1 foram: diquat (Reward a 204 g i.a. ha-1; diquat a 102 e 204 g i.a. ha-1 + Agral a 0,1%; 2,4-D (DMA 806 BR a 167, 335, 670 e 1.340 g e.a. ha-1; glyphosate (Rodeo a 3.360 g e.a. ha-1 + Aterbane a 0,5%; e imazapyr (Arsenal a 250 g e.a. ha-1. As parcelas foram constituídas por caixas d'água de 0,60 x 0,60 x 0,45 m, com 120 litros de água + 20 litros de solo e 20 ramos por caixa. Utilizou-se um pulverizador costal a pressão constante de CO2 a 2 bar, pontas 110.02 VS, com um consumo de calda de 180 l ha-1. O controle foi avaliado visualmente aos 2, 6, 9,11, 13, 17, 20, 23, 26, 30 e 36 dias após a aplicação dos herbicidas (DAAH. Inicialmente, o herbicida diquat foi o composto que apresentou os sintomas mais severos de intoxicação nos ramos de pinheiro-d'água aos 2 DAAH, com 65% de controle em média, e aos 20 DAAH ele atingiu o controle máximo (99%, porém ocorreram rebrotas a partir dos 23 DAAH, independentemente da adição ou não de Agral e das doses testadas. O herbicida 2,4-D proporcionou 100% de controle dos ramos a partir dos 23 DAAH para as doses de 1.340 e 670 g ha-1, não ocorrendo rebrotas; já para as demais doses testadas (335 e 167 g ha-1 o controle não foi eficiente, pois ocorreram rebrotas. Os herbicidas glyphosate e imazapyr não foram eficientes no controle desta espécie.This work was carried out at the Advanced Weed Research Nucleus - UNESP, Botucatu-SP, to evaluate the control of Myriophyllum aquaticum by applying different herbicides in post emergence. The herbicides and doses (g ha-1 tested were: diquat (Reward at 204 g a.i. ha-1, diquat at 102 and 204 g a.i. ha-1 + agral at 0.1% v/v; 2,4-D (DMA 806 BR at 1,340, 670, 335 and 167 g a.e. ha-1; glyphosate (Rodeo at 3.360 g a.e. ha-1

POTENSI DAN KARAKTERISTIK PRODUKSI Lemna minor PADA BERBAGAI MEDIA TANAM

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Iwan Prihantoro

2015-06-01

Full Text Available Lemna minor merupakan jenis tanaman yang hidup dominan pada perairan dengan kualitas nutrisi tinggi dan potensial sebagai sumber hijauan pakan bagi ternak. Penelitian ini bertujuan untuk mengukur potensi Lemna minor dan karakteristiknya pada berbagai media tanam untuk mendapatkan teknik produksi yang optimal. Penelitian dilakukan pada bak plastik dengan ukuran 36.5×27×10 cm3 selama dua minggu. Rancangan yang digunakan adalah Acak Lengkap (RAL dengan lima perlakuan media dan lima ulangan. Jenis media yang digunakan adalah kontrol, hoagland, hyponex, kompos dan NPK. Parameter yang diukur meliputi serapan nitrogen, pH media, cover area, penyusutan media, dan produksi biomassa. Hasil penelitian menunjukkan bahwa lemna minor efektif dalam memanfaatkan nitrogen dengan nilai serapan > 98 %, media kompos memberikan status pH media yang stabil/netral dan pertambahan luas cover area (LCA tercepat dan tingkat produksi biomassa Lemna minor terbaik pada media kompos dan Hoagland.

Development of a Biological Control Program for Eurasian Watermilfoil (Myriophyllum spicatum)

Science.gov (United States)

2008-08-01

Eignung einer Insektengruppe für die Fauna - Flora -Habitat-Richtlinie der EU (92/43/EWG, 21. Mai 1992) am Beispiel der Rüsselkäfer-Unterfamilie Bagoinae... y Approved for public release; distribution is unlimited. Aquatic Plant Control Research Program ERDC/EL TR-08-22 August 2008 Development of...Survey). .............................. 7 Tables Table A1. Known Myriophyllum species in Eurasia, North and South America, and Africa ..............26

Arsenic uptake by Lemna minor in hydroponic system.

Science.gov (United States)

Goswami, Chandrima; Majumder, Arunabha; Misra, Amal Kanti; Bandyopadhyay, Kaushik

2014-01-01

Arsenic is hazardous and causes several ill effects on human beings. Phytoremediation is the use of aquatic plants for the removal of toxic pollutants from external media. In the present research work, the removal efficiency as well as the arsenic uptake capacity of duckweed Lemna minor has been studied. Arsenic concentration in water samples and plant biomass were determined by AAS. The relative growth factor of Lemna minor was determined. The duckweed had potential to remove as well as uptake arsenic from the aqueous medium. Maximum removal of more than 70% arsenic was achieved atinitial concentration of 0.5 mg/1 arsenic on 15th day of experimental period of 22 days. Removal percentage was found to decrease with the increase in initial concentration. From BCF value, Lemna minor was found to be a hyperaccumulator of arsenic at initial concentration of 0.5 mg/L, such that accumulation decreased with increase in initial arsenic concentration.

A Comparison of growth on mercuric chloride for three Lemnaceae species reveals differences in growth dynamics that effect their suitability for use in either monitoring or remediating ecosystems contaminated with mercury.

Science.gov (United States)

Yang, Jingjing; Li, Gaojie; Bishopp, Anthony; Heenatigala, P. P. M.; Hu, Shiqi; Chen, Yan; Wu, Zhigang; Kumar, Sunjeet; Duan, Pengfei; Yao, Lunguang; Hou, Hongwei

2018-04-01

Mercury (Hg) is a toxic heavy metal that can alter the ecological balance when it contaminates aquatic ecosystems. Previously, researchers have used various Lemnaceae species either to monitor and/or remove heavy metals from freshwater systems. As Hg contamination is a pressing issue for aquatic systems worldwide, we assessed its impact on the growth of three commonly species of Lemnaceae - Lemna gibba 6745, Lemna minor 6580 and Spirodela polyrhiza 5543. We exposed plants to different concentrations of mercuric chloride (HgCl2) and monitored their growth, including relative growth rate, frond number, and fresh weight. These data were coupled with measurements of starch content, levels of photosynthetic pigment and the activities of antioxidant substances. The growth of all three lines showed significant negative correlations with Hg concentrations, and starch content, photosynthetic pigment, soluble protein and antioxidant enzymes levels were all clearly affected. Our results indicate that the L. gibba line used in this study was the most suitable of the three for biomonitoring of water contaminated with Hg. Accumulation of Hg was highest in the S. polyrhiza line with a bioconcentration factor over 1000, making this line the most suitable of the three tested for use in an Hg bioremediation system.

A Comparison of Growth on Mercuric Chloride for Three Lemnaceae Species Reveals Differences in Growth Dynamics That Effect Their Suitability for Use in Either Monitoring or Remediating Ecosystems Contaminated With Mercury

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Jingjing Yang

2018-04-01

Full Text Available Mercury (Hg is a toxic heavy metal that can alter the ecological balance when it contaminates aquatic ecosystems. Previously, researchers have used various Lemnaceae species either to monitor and/or remove heavy metals from freshwater systems. As Hg contamination is a pressing issue for aquatic systems worldwide, we assessed its impact on the growth of three commonly species of Lemnaceae- Lemna gibba 6745, Lemna minor 6580 and Spirodela polyrhiza 5543. We exposed plants to different concentrations of mercuric chloride (HgCl2 and monitored their growth, including relative growth rate, frond number (FN, and fresh weight (FW. These data were coupled with measurements of starch content, levels of photosynthetic pigment and the activities of antioxidant substances. The growth of all three lines showed significant negative correlations with Hg concentrations, and starch content, photosynthetic pigment, soluble protein and antioxidant enzymes levels were all clearly affected. Our results indicate that the L. gibba line used in this study was the most suitable of the three for biomonitoring of water contaminated with Hg. Accumulation of Hg was highest in the S. polyrhiza line with a bioconcentration factor over 1,000, making this line the most suitable of the three tested for use in an Hg bioremediation system.

Botanical ecology and conservation of the laguna de la herrera (sabana de bogotá, colombia)

OpenAIRE

Wijninga, V. M.; Rangel, Orlando; Cleef, A. M.

2012-01-01

Se estudió la vegetación alrededor de la Laguna de La Herrera, una laguna andina a 2550 m. Se diferenciaron una comunidad de Phytolacca bogotensis (1): comunidades helofíticas dominadas por: Scirpus californicus y Typha angustifolia (2); Scirpus californicus (3); Polygonum punctatum (4); Rumex obtusifolius y Polygonum punctatum (5); Bidens laevis (6); Hydrocotyle ranunculoides (7); comunidades pleustofíticas con: Limnobium laevigatum; (8); Azolla filiculoides y Lemna cf. gibba (9) y Eichhorni...

EVALUACIÓN DE LA PLANTA Lemna minor COMO BIORREMEDIADORA DE AGUAS CONTAMINADAS CON MERCURIO

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Adolfo D. Arenas

2011-01-01

Full Text Available Se evaluó la capacidad biorremediadora de Lemna minor en función del tiempo en aguas contaminadas con mercurio mediante un diseño experimental de 3 bloques al azar con cinco réplicas: un grupo experimental con 100 g de Lemna, 7,5 L de agua contaminada con Hg (0,13 mgL-1 y solución nutritiva; un grupo Testigo con 100 g de Lemna, 7,5 L de agua y solución nutritiva y un grupo control con mercurio al nivel de 0,13 mgL-1 en agua destilada sin plantas. La eficiencia de remoción de mercurio de la Lemna minor, en 22 días, fue de 30%. Las variables peso fresco, peso seco, y nitrógeno y fósforo foliares no presentaron diferencias significativas entre los dos tratamientos. La absorción de potasio, fue afectada por los niveles de mercurio. La planta Lemna minor representa una alternativa para la remoción de mercurio en aguas contaminadas hasta un nivel de 0,13 mg/L.

Influence of ozone on RNA and protein content of Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Craker, L E

1972-01-01

The amount of RNA and protein in Lemna minor L. plants decreased after exposure to ozone, as compared with control plants receiving no ozone treatment. Differences in RNA and protein content between control and ozone-treated Lemna plants were detectable immediately following ozone treatments and remained throughout the 24 h sampling time.

Aspartokinase in Lemna minor L

Science.gov (United States)

Wong, Kwan F.; Dennis, David T.

1973-01-01

The growth of Lemna minor was followed by means of frond number, fresh weight, and dry weight measurements in the presence of various amino acids at a concentration 0.25 mm. Lysine inhibited growth but not to the same extent as threonine and homoserine. Isoleucine was also an inhibitor of growth. In the presence of methionine there was some growth for 2 to 3 days, but by 5 days most of the plants appeared to be dead. When lysine and threonine were added together, there was no growth at all, and the plants were dead after 5 days. This effect of lysine + threonine could be reversed by adding methionine or homoserine to the growth medium. The isolated aspartokinase from Lemna showed inhibition by lysine and higher concentrations of threonine. When these amino acids were added together at low concentrations, there was a concerted inhibition of the aspartokinase. It is suggested that some effects of amino acids on the growth of L. minor can be explained on the basis of a concerted feedback control of aspartokinase. Images PMID:16658324

Caracterización molecular por patrones electroforéticos de isoenzimas esterasas en Lemna aequinoctialis y Lemna valdiviana (lemnaceae de Costa Rica (ING

Directory of Open Access Journals (Sweden)

Sharon Jiménez Delgado

2016-03-01

Full Text Available The Lemnaceae family lacks morphologic and anatomical characteristics with comparative aims and for that reason the molecular studies has been necessary a differentiation. In Costa Rica there are two species of Lemna: Lemna aequinoctialis and Lemna valdiviana. With the objective of a molecular characterization and differentiation of both species were extracted isoenzymes esterases. The study was carried out in the Molecular Genetics Laboratory of the School of Biological Sciences at Universidad Nacional, Heredia, Costa Rica. The technical electrophoresis in gel of polyacrylamida SDS-PAGE was used. It was difference in the pattern of isoenzymes between both species. According to previous molecular studies based on morphology and anatomy, flavonoides, isoenzymes, and DNA sequences of certain genes both species are very different; in addition they belong to different monophyletics groups. On the other hand, the importance of this molecular characterization is its possible use in water treatment, because the esterases have had important in the bioremediation. Also, species of the Lemnaceae family are used in the water treatment like bioremediation.

Distribution and Abundance of Eurasian Watermilfoil (Myriophyllum spicatum L.) and Curly-Leaf Pondweed (Potamogeton crispus L.) in Shawano Lake, Wisconsin

National Research Council Canada - National Science Library

Owens, Chetta S; James, William F; Skogerboe, John G; Smart, R. M

2007-01-01

... (Potamogeton crispus L.) and Eurasian watermilfoil (Myriophyllum spicatum L.). In addition to problems associated with invasive plant species, Shawano Lake has been experiencing declining water quality associated with phosphorus (P...

Knopkroos (Lemna turionifera Landolt) nieuw voor Nederland

NARCIS (Netherlands)

Wolff, Peter; Bruinsma, John

2005-01-01

Lemna turionifera, een continentale en subatlatische soort, wordt sinds 1992 ook in Nederland waargenomen. Knopkroos kan worden onderscheiden van L. minor door zijn roodachtige kleur, de vorming van echte turionen, en door dunnere, kleinere, meer symmetrische schijfjes met een onopvallende apicale

Phytotoxicity of silver nanoparticles to Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Gubbins, Eva J. [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Batty, Lesley C., E-mail: l.c.batty@bham.ac.uk [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Lead, Jamie R. [Department of Geography and Environmental Science, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom)

2011-06-15

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. Although there has been some attempt to determine the toxic effects of AgNPs, there is little information on aquatic plants which have a vital role in ecosystems. This study reports the use of Lemna minor L. clone St to investigate the phytotoxicity of AgNPs under modified OECD test conditions. AgNPs were synthesised, characterised and subsequently presented to the L. minor. Results showed that inhibition of plant growth was evident after exposure to small ({approx}20 nm) and larger ({approx}100 nm) AgNPs at low concentrations (5 {mu}g L{sup -1}) and this effect became more acute with a longer exposure time. There was a linear dose-response relationship after 14 d exposure. Using predicted environmental concentrations for wastewaters it was found that AgNPs may pose a significant potential risk to the environment. - Highlights: > Silver nanoparticles are toxic to Lemna minor at concentrations of 5 {mu}g L{sup -1}. > The effect of silver nanoparticles varies with size and concentration. > Standard toxicity tests are not appropriate for application to NPs. > Silver nanoparticles pose a potential environmental risk based on modelled environmental concentrations. - Silver nanoparticles are toxic to Lemna minor at low concentrations and constitute a significant environmental risk.

Phytotoxicity of silver nanoparticles to Lemna minor L

International Nuclear Information System (INIS)

Gubbins, Eva J.; Batty, Lesley C.; Lead, Jamie R.

2011-01-01

The use of silver nanoparticles (AgNPs) in commercial products has increased significantly in recent years. Although there has been some attempt to determine the toxic effects of AgNPs, there is little information on aquatic plants which have a vital role in ecosystems. This study reports the use of Lemna minor L. clone St to investigate the phytotoxicity of AgNPs under modified OECD test conditions. AgNPs were synthesised, characterised and subsequently presented to the L. minor. Results showed that inhibition of plant growth was evident after exposure to small (∼20 nm) and larger (∼100 nm) AgNPs at low concentrations (5 μg L -1 ) and this effect became more acute with a longer exposure time. There was a linear dose-response relationship after 14 d exposure. Using predicted environmental concentrations for wastewaters it was found that AgNPs may pose a significant potential risk to the environment. - Highlights: → Silver nanoparticles are toxic to Lemna minor at concentrations of 5 μg L -1 . → The effect of silver nanoparticles varies with size and concentration. → Standard toxicity tests are not appropriate for application to NPs. → Silver nanoparticles pose a potential environmental risk based on modelled environmental concentrations. - Silver nanoparticles are toxic to Lemna minor at low concentrations and constitute a significant environmental risk.

EVALUACIÓN DE LA PLANTA Lemna minor COMO BIORREMEDIADORA DE AGUAS CONTAMINADAS CON MERCURIO

OpenAIRE

Adolfo D. Arenas; Lué-Merú Marcó; Gosmyr Torres

2011-01-01

Se evaluó la capacidad biorremediadora de Lemna minor en función del tiempo en aguas contaminadas con mercurio mediante un diseño experimental de 3 bloques al azar con cinco réplicas: un grupo experimental con 100 g de Lemna, 7,5 L de agua contaminada con Hg (0,13 mgL-1) y solución nutritiva; un grupo Testigo con 100 g de Lemna, 7,5 L de agua y solución nutritiva y un grupo control con mercurio al nivel de 0,13 mgL-1 en agua destilada sin plantas. La eficiencia de remoción de mercurio de la L...

Attempts at establishing the culture conditions for Lemna minor L.

Directory of Open Access Journals (Sweden)

M. Krzychowska

2015-01-01

Full Text Available The influence of the concentration, composition and pH of the substrate as well as of light intensity on the growth and vegetative propagation of Lemna minor L. was investigated. The media of Hutner, Hoagland and Pirson and Seidel were used. At first the experiments were carried out under unsterile conditions. Later sterilized duckweed was cultured in aseptic conditions. The dry matter was determined. Surface area increment and an increase in the number of fronds were evaluated by the planimetric method. For total protein determination in Lemna minor L. from unsterile and sterile cultures Lowry's method was used.

EKOGENOTOKSISITAS LIMBAH CAIR BATIK DAN EFEK ANTIMUTAGENIK Lemna minor TERHADAP ERITROSIT IKAN NILA (Oreochromis niloticus

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Erma Musbita Tyastuti

2016-09-01

Full Text Available Limbah cair batik di Solo sebagian besar dibuang langsung ke perairan tanpa diolah terlebih dahulu dan menyebabkan pencemaran air. Kandungan logam berat di dalam limbah cair batik dapat memicu efek genotoksik seperti pembentukan mikronukleus. Lemna minor berpotensi sebagai antimutagen dan mencegah pembentukan mikronukleus karena mengandung senyawa aktif seperti karoten dan asam amino. Penelitian ini bertujuan untuk mengetahui ekogenotoksisitas limbah cair batik dan efek antimutagenik Lemna minor terhadap eritrosit ikan nila. Penelitian dilakukan di Laboratorium Biologi UMS dengan pemaparan limbah cair batik 0ppm/L, 2500 ppm/L, 5000 ppm/L dan 7500 ppm/L terhadap 2 kelompok ikan nila dengan diet pelet dan Lemna minor. Hasil penelitian menunjukkan bahwa paparan limbah cair batik memicu pembentukan mikronukleus dengan frekwensi tertinggi pada konsentrasi paparan 7500 ppm/L. Lemna minor juga terbukti memiliki potensi antimutagenik karena mampu menekan frekwensi mikronukleus lebih rendah dibandingkan diet pelet.

Lead pollution: effects on chlorophyll. [Phalaris canariensis, Lemna minor, graminaceae

Energy Technology Data Exchange (ETDEWEB)

Fiussello, N

1973-01-01

The emissions of motors are responsible for the high concentrations of lead in soil and plants near roads. In man, when the concentration of lead in blood exceeds the value of 30 ..mu..g/100 ml, is shown a decrease of haemaglobin and an increase of ALA urinary content. Since the early stages of chlorophyll biosynthetic pathway are similar if not identical with those leading to haem as far as protoporphyrin IX, it is interesting to ascertain if lead can specifically interfere in chlorophyll biosynthesis. In sand cultures with 200 p.p.m. of lead (the conc. in roadside soils), after 2 weeks, wheat shows a diminution of 16,5% in fresh weight 7,5% in dry weight and 6,5% in chlorophyll; Phalaris canariensis shows a diminution of 68% f.w., 41% d.w. and 39% chl. in comparison with the controls. A water-plant, Lemna minor, is more sensitive: the chlorophyll content, referred to dry weight, shows after a week a diminution of 32% and 55% with 10/sup -4/M and 10/sup -3/M lead nitrate. Lead in 200 p.p.m. conc. is surely poisonous against the tested plants but a specific action on chlorophyll synthesis could be accepted, at present, only for Lemna minor. It is possible that in wheat and in Phalaris a part of lead is bound in root-system, the more damaged, while in Lemna it can reach more easily the chloroplasts. At present a detectable increase of ALA, in plants treated with lead, has not been proved both in Graminaceae and in Lemna minor.

Haloacetic acids in the aquatic environment. Part II: ecological risk assessment

International Nuclear Information System (INIS)

Hanson, Mark L.; Solomon, Keith R.

2004-01-01

Haloacetic acids (HAAs) are environmental contaminants found in aquatic ecosystems throughout the world as a result of both anthropogenic and natural production. The ecological risk posed by these compounds to organisms in freshwater environments, with a specific focus on aquatic macrophytes, was characterized. The plants evaluated were Lemna gibba, Myriophyllum spicatum and M. sibiricum and the HAAs screened were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). Laboratory toxicity data formed the basis of the risk assessment, but field studies were also utilized. The estimated risk was calculated using hazard quotients (HQ), as well as effect measure distributions (EMD) in a modified probabilistic ecological risk assessment. EMDs were used to estimate HAA thresholds of toxicity for use in HQ assessments. This threshold was found to be a more sensitive measure of low toxicity than the no observed effect concentrations (NOEC) or the effective concentration (EC 10 ). Using both deterministic and probabilistic methods, it was found that HAAs do not pose a significant risk to freshwater macrophytes at current environmental concentrations in Canada, Europe or Africa for both single compound and mixture exposures. Still, HAAs are generally found as mixtures and their potential interactions are not fully understood, rendering this phase of the assessment uncertain and justifying further effects characterization. TCA in some environments poses a slight risk to phytoplankton and future concentrations of TFA and CDFA are likely to increase due to their recalcitrant nature, warranting continued environmental surveillance of HAAs. - Current environmental concentrations of haloacetic acids do not pose a risk to aquatic macrophytes, but could impact plankton

Dwergkroos (Lemna minuscula Herter) nieuw voor Nederland

NARCIS (Netherlands)

Schaminée, Joop H.J.; Hermans, Jan T.

1989-01-01

Lemna minuscula was found for the first time in the Netherlands in the Meggelveld area, a complex of claypits in Central Limburg. This American species, in Europe first recorded in southern France in 1966, is expanding its area to the north and east. The habitat and growth form in the Meggelveld

Botanical ecology and conservation of the Laguna de la Herrera (Sabana de Bogotá, Colombia Botanical ecology and conservation of the Laguna de la Herrera (Sabana de Bogotá, Colombia

Directory of Open Access Journals (Sweden)

Wijninga V. M.

1989-09-01

Full Text Available The acuatic, helophytic and pleustophytic vegetation of the Laguna de La Herrera, on the southwestern border of the high plain of Bogotá at 2550 m was studied following the Zurich- Montpellier approach. The communities recognized were: terrestrial community of Phytolacca bogotensis; helophytic communities of scirpus californicus and Typha angustifolia ; scirpus californicus ; Polygonum punctatum ; Rumex obtusifolius with Polygonum punctatum; Bidens laevis ; Hydrocotyle ranunculoides. Pleustophytic communities of Limnobium laevigatum; Azolla filiculoides with Lemna cf. gibba and Eichornia crassipes. The structure, floristic composition and ecological aspects were also considered. Several recommendations about conservation of the Laguna are given. Se estudió la vegetación alrededor de la Laguna de La Herrera, una laguna andina a 2550 m. Se diferenciaron una comunidad de Phytolacca bogotensis (1: comunidades helofíticas dominadas por: Scirpus californicus y Typha angustifolia (2; Scirpus californicus (3; Polygonum punctatum (4; Rumex obtusifolius y Polygonum punctatum (5; Bidens laevis (6; Hydrocotyle ranunculoides (7; comunidades pleustofíticas con: Limnobium laevigatum; (8; Azolla filiculoides y Lemna cf. gibba (9 y Eichhornia crassipes (10. Se registraron la estructura, composición florística, los rasgos ecológicos y la distribución de las comunidades y se comparó con la conductividad eléctrica y la calidad del agua. Finalmente, se hacen recomendaciones para la conservación de la laguna y la vegetación acuática.

Fate of antimicrobials in duckweed Lemna minor wastewater treatment systems.

Science.gov (United States)

Iatrou, Evangelia I; Gatidou, Georgia; Damalas, Dimitrios; Thomaidis, Nikolaos S; Stasinakis, Athanasios S

2017-05-15

The fate of four antimicrobials (cefadroxil, CFD; metronidazole, METRO; trimethoprim, TRI; sulfamethoxazole, SMX) was studied in Lemna minor systems and the role of different mechanisms on their removal was evaluated. All micropollutants were significantly removed in batch experiments with active Lemna minor; the highest removal was observed for CFD (100% in 14 d), followed by METRO (96%), SMX (73%) and TRI (59%) during 24 d of the experiment. Calculation of kinetic constants for hydrolysis, photodegradation, sorption to biomass and plant uptake revealed significant differences depending on the compound and the studied mechanism. For METRO, TRI and SMX the kinetic constants of plant uptake were by far higher comparing to those of the other mechanisms. The transformation products of antimicrobials were identified using UHPLC-QToF-MS. Two were the main degradation pathways for TRI; hydroxylation takes place during both phyto- and photodegradation, while demethylation occurs only in absence of Lemna minor. The operation of a continuous-flow duckweed system showed METRO and TRI removal equal to 71±11% and 61±8%, respectively. The application of mass balance and the use of published biodegradation constants showed that plant uptake and biodegradation were the major mechanisms governing METRO removal; the most important mechanism for TRI was plant uptake. Copyright © 2017 Elsevier B.V. All rights reserved.

A SEDIMENT TOXICITY METHOD USING LEMNA MINOR, DUCKWEED

Science.gov (United States)

We developed a Lemna minor sediment toxicity test method to assess sediment contaminants which may affect plants. This 96-hour test used 15 ml of sediment and 2 ml of overlying water which was renewed after 48 hours. Sand was used as the control sediment and also to dilute test ...

Productivity of duckweed (Lemna minor as alternative forage feed for livestock in different light intensities

Directory of Open Access Journals (Sweden)

Uti Nopriani

2015-12-01

Full Text Available Duckweed (Lemna minor is a small aquatic plant that grow and float in water and spread extensively. Lemna minor is potential as a source of high quality forage. This study aimed to determine optimal light intensity on Lemna minor to generate maximum productivity. Parameters observed were physical-biological and chemical characteristics of the media (pH value, temperature, cover area, decreased of media volume, BOD, COD, nitrate, nitrite and phosphate, plant growth acceleration (number of shoots, leaf diameter and chlorophyll-a, biomass production, doubling time of cover area and the number of daughters. This study was done based on a completely randomized design with 4 levels of shading. While treatment was: without shading, shading 30%, shading 50% and shading 70% using paranet shade. Each treatment consisted of 4 replications. Result showed that the productivity of Lemna minor included the number of daughters, chlorophyll-a, biomass production, cover area, absorbed phosphate and doubling time the number of daughters reached the highest level without shading treatment (1007,21-2813,57 lux. The decrease of intensity of light, the increase the diameter of leaf. Decrease of media volume was positively correlated to size of cover area. Biomass production influenced by a wide doubling time of cover area and number of daughters.

Delimiting invasive Myriophyllum aquaticum in Kashmir Himalaya using a molecular phylogenetic approach.

Science.gov (United States)

Shah, M A; Ali, M A; Al-Hemaid, F M; Reshi, Z A

2014-09-12

Myriophyllum aquaticum (Vell.) Verdc. (family Haloragaceae) is one of the most invasive and destructive South American aquatic plant species and is present in a wide range of geographic regions, including the Kashmir Himalaya. Confusion regarding the taxonomic delimitation of M. aquaticum in the Himalayan region impedes effective and targeted management. Hence, our goal was improve the identification of M. aquaticum for exclusive delimitation from other related species in the study region using a molecular phylogenetic approach. A maximum parsimony tree recovered from phylogenetic analyses of the internal transcribed spacer sequences of nuclear ribosomal DNA was used to authenticate the identification of M. aquaticum. The results of this study can be used for targeted management of this tropical invader into the temperate Kashmir Himalaya.

Adjuvants affect duckweed (Lemna minor) control with pelargonic acid

Science.gov (United States)

Duckweeds (Lemna spp.) are small, free floating, aquatic plants that flourish on stagnant or slow-moving water surfaces throughout the world. Members of the genus are among the smallest flowering plants, providing food for fish and fowl, but their aggressive growth and invasive tendencies make them ...

DEVELOPMENT OF THE DUCKWEED (LEMNA MINOR GENETIC TRANSFORMATION SYSTEM

Directory of Open Access Journals (Sweden)

Sofia E Gaydukova

2008-12-01

Full Text Available Regeneration parameters were optimized and effective selection conditions were sorted out. Transgenic plants of Lemna minor were obtained and their status was confirmed by molecular analysis. Optimized methodology can be used for obtaining transgenic duckweed plants producing recombinant proteins and water body bioremediators.

Potential of macrophytes for removing atrazine from aqueous solution Potencial de macrófitas para remoção de atrazine de solução aquosa

Directory of Open Access Journals (Sweden)

F.P Guimarães

2011-01-01

Full Text Available The potential of three macrophytes, Azolla caroliniana, Salvinia minima, and Lemna gibba was assessed in this study to select plants for use in environmental remediation contaminated with atrazine. Experiments were carried out in a greenhouse over six days in pots containing Hoagland 0.25 strength nutritive solution at the following atrazine concentrations: 0; 0.01; 0.1; 1.0; 10.0 mg L-1. Decrease in biomass accumulation was observed in the three macrophytes, as well as toxic effects evidenced by the symptomatology developed by the plants which caused their deaths. The chlorosis and necrosis allowed to observe in the plants the high sensitivity of the three species to the herbicide. Plants presented low potential for removal of atrazine in solution when exposed to low concentrations of the herbicide. However, at the 10.0 mg L-1 atrazine concentration, L. gibba and A. caroliniana showed potential to remove the herbicide from the solution (0.016 and 0.018 mg atrazine per fresh mass gram, respectively. This fact likely resulted from the processes of atrazine adsorption by the dead material. The percentage of atrazine removed from the solution by the plants decreased when the plants were exposed to high concentrations of the pollutant. Azolla caroliniana, S. minima, and L. gibba were not effective in removing the herbicide from solution. The use of these species to remedy aquatic environments was shown to be limited.Avaliou-se, neste estudo, o potencial de três macrófitas - Azolla caroliniana, Salvinia minima e Lemna gibba - com vistas à seleção de plantas para remediação de ambientes contaminados por atrazine. Foram realizados experimentos em casa de vegetação durante seis dias, em vasos contendo solução nutritiva Hoagland (0,25 de força iônica, nas seguintes concentrações de atrazine: 0; 0,01; 0,1; 1,0; e 10,0 mg L-1. A redução da biomassa acumulada pelas macrófitas foi observada, bem como os efeitos de toxidez evidenciados pela

A FLOW-THROUGH TESTING PROCEDURE WITH DUCKWEED (LEMNA MINOR L.)

Science.gov (United States)

Lemna minor is one of the smallest flowering plants. Because of its floating habit, ease of culture, and small size it is well adapted for laboratory investigations. Procedures for flow-through tests were developed. Testing procedures were developed with this apparatus. By using ...

NEW METHOD FOR DETERMINING EFFLUENT TOXICITY USING DUCKWEED (LEMNA MINOR)

Science.gov (United States)

Duckweed (Lemna minor), a small vascular plant, grows rapidly, is sensitive to a wide variety of toxicants and is easy to culture. ethod is described that measures duckweed frond growth and chlorophyll levels as indicators of growth inhibition. he method requires a small testing ...

Competition Between Lemna minuta, Lemna minor, and Azolla filiculoides. Growing Fast or Being Steadfast?

Directory of Open Access Journals (Sweden)

Simona Paolacci

2018-06-01

Full Text Available A substantial number of Lemnaceae are invasive outside their natural distribution area. Lemna minuta is considered invasive in several European countries, where it can occur in the same habitat as invasive Azolla filiculoides and native Lemna minor. In this study the presence, abundance and growth rates of all three species were monitored across 24 natural ponds and in a series of mesocosms in order to explore the importance of species invasiveness and habitat invisibility. Field monitoring showed that the distribution of the three species of macrophytes is heterogeneous in space and time. However, the data show no association of nutrient or light levels with plant distribution. Indeed, using reciprocal transplanting experiments it was demonstrated that all species are able to grow in all ponds, even ponds where the species do not naturally occur. It is concluded that distribution of L. minor, L. minuta, and A. filiculoides is not limited by the prevailing physicochemical characteristics of the ponds during the summer period. Remarkably, in these experiments A. filiculoides displayed the highest RGR, and exerted a negative influence on growth rates and surface cover of L. minor and L. minuta. Despite such apparent invasiveness, A. filiculoides was relatively rare in the study area. Rather, the species most abundant was L. minor which has the lowest RGR under field conditions in summer. Therefore, this study shows that the invasiveness of the species during the summer months is not necessarily reflected in the actual distribution pattern in natural ponds. In fact, alien L. minuta and A. filiculoides are under-represented in the monitored area. It is concluded that the interaction of several factors, including growth under winter-conditions and/or dispersal after disturbances, is the major determinant of the abundance and heterogeneous distribution of L. minor, L. minuta, and A. filiculoides in the study area.

Ecological differentiation of Lemna minor L. and Spirodela polyrrhiza (L. Schleiden populations

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Hanna Wożakowska-Natkaniec

2015-01-01

Full Text Available The subject of thep resent study are 19 natural, ecological populations of Lemna minor and Spirodela polyrrhiza coming from sixteen habitats in Lower Silesia. The study showed the essential differences between ecological populations of both species, conditioned on chemistry (pH, level N, P, K, Ca, Mg and Fe and the natural water radioactivity. It was shown experimentally that these populations, in nature, establish a set of ecotypes or ecophene variability. Ecotypic differentiation of populations of Lemna minor and Spirodela polyrrhiza is based upon individual features and population characteristics such as: shape and size of plants, plant frequency of two, three, and four fronds, the ratio of right- to left-handed plants, and the dynamics of growth and biomass production.

Growth limitation of Lemna minor due to high plant density

NARCIS (Netherlands)

Driever, S.M.; Nes, van E.H.; Roijackers, R.M.M.

2005-01-01

The effect of high population densities on the growth rate of Lemna minor (L.) was studied under laboratory conditions at 23°C in a medium with sufficient nutrients. At high population densities, we found a non-linear decreasing growth rate with increasing L. minor density. Above a L. minor biomass

Ecotoxicological evaluation of two anti-dandruff hair shampoos using Lemna minor.

Science.gov (United States)

Azizullah, Azizullah; Shakir, Shakirullah Khan; Shoaib, Shahana; Bangash, Halima; Taimur, Nadia; Murad, Waheed; Daud, Muhammad Khan

2018-04-04

Hair shampoos, a mixture of various organic and organic compounds, are commonly used personnel care products. Since shampoos are used in almost every household and beauty shop, their ingredients are common components of domestic and municipal wastewater. However, studies on the effect of shampoos to aquatic plants can hardly be found in literature. Therefore, the present study was conducted to investigate the phytotoxic effects of two commonly used anti-dandruff shampoos (named here AD 1 and AD 2) using Lemna minor as a biotest organism. For toxicity assessment, frond number, fresh and dry biomass, and light-harvesting pigments (chlorophyll a, b and total carotenoids) of Lemna were used as end points. Five different concentrations (0.001, 0.01, 0.1, 1, and 5%) of each shampoo were tested in comparison to the control. At lower concentrations of shampoos, some minor and non-significant stimulatory effects were observed in some parameters, but at concentrations above 0.01% both the shampoos significantly inhibited almost all parameters in Lemna. The EC 50 values obtained for frond number were 0.034 and 0.11% for AD 1 and AD 2, respectively. The fresh biomass gave EC 50 values of 0.07 and 0.066% for AD 1 and AD 2, respectively. Based on the preset study, it can be speculated that shampoo contamination at higher concentrations in water bodies can be a threat to aquatic organisms. This study can be used as a baseline to further investigate shampoo toxicity using other species and to explore the mechanism of shampoo toxicity in aquatic plants.

Physiology and plastic fine structure of deetiolating Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Frick, H; Jones, R F

1976-08-01

During the 12-h lag period in chlorophyll accumulation after the onset of white-light illumination of Lemna minor etiolated for 35 days, a rapid increase in visible fronds per culture occurred. This new frond production then assumed a log-linear rate of increase, and total protein per unit fresh weight came to parallel the rate of increase in fresh weight per plant. The ribosomal RNA content of 45-day-etiolated plants was deficient in 23S and 16S species compared with green plants. The prolamellar bodies of etioplasts were either tightly or loosely paracrystalline within the same cell; they were without extended perforate lamellae, which developed during far-redlight illumination even while prolamellar bodies persisted. The development of chloroplasts in deetiolating L. minor was typical of other higher plants. The developmental sequence in green Lemna included proplastid to deeply stacked granal chloroplast within several millimeters. Plastid profiles suggestive of division configurations occurred only in primordial cells of green and etiolated plants. The relatively small numbers of plastids in any given stage of differentation may account for the sensitivity of plastid development to inhibitors of protein and nucleic acid synthesis.

Prey composition in the carnivorous plants Utricularia inflata and U. gibba (Lentibulariaceae from Paria Peninsula, Venezuela

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Elizabeth Gordon

2007-12-01

Full Text Available Las plantas carnívoras acuáticas del género Utricularia (Lentibulariaceae, capturan pequeños organismos acuáticos, como rotíferos, copépodos, y cladóceros, por medio de estructuras anatómicas semejantes a vesículas. Este estudio tuvo como objetivo determinar el tamaño y tipo de presas de U. gibba y U. inflata, recolectados en un pequeño lago y en un pastizal inundado, respectivamente, en la localidad de la Península de Paria (Estado Sucre, Venezuela. La acidez, conductividad, cantidad de oxígeno disuelto y la salinidad del agua se midieron in situ para cada sitio de muestreo; también se tomaron muestras de agua para determinar niveles de N-Kjeldahl, P-total, Na+, K+, Ca++, Mg++ y Cl-. Se midieron cincuenta vesículas de cada especie y se analizaron sus contenidos. Los valores de N-Kjeldahl y P-total fueron similares en ambos sitios, y semejantes a los conocidos para ecosistemas eutróficos; sin embargo, las concentraciones de Na+, K+, Ca++, Mg++ y los valores in situ de los parámetros del agua fueron más altos en el pastizal inundado. Las vesículas contenían los siguientes grupos de zooplancton: rotíferos, cladóceros, copépodos, anélidos, rizópodos, e insectos; y las siguientes divisiones de fitoplancton: Bacillariophyta, Chlorophyta, Cyanophyta y Euglenophyta. Las vesículas presentadas por U. inflata fueron menores en tamaño y en cantidad, pero mayores en abundancia y riqueza total de morfoespecies algales y animales en comparación con U. gibba. La similitud en cuanto a composición de presas a nivel taxonómico, entre las dos especies de plantas carnívoras, fue baja.

Batch Removal of Acid Blue 292dye by Biosorption onto Lemna minor: Equilibrium and Kinetic Studies

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Ali Joghataei

2016-12-01

Full Text Available Background: Recently, there has been a great concern about the consumption of dyes because of their toxicity, mutagenicity, carcinogenicity, and persistence in the aquatic environment. Therefore, the aim of this study was to determine the feasibility of using Lemna minor for Acid Blue 292 (AB292 dye removal from aqueous solution and to determine the optimal conditions. Methods: This experimental study was conducted in the batch systems to investigate the effects of parameters such as contact time, initial concentration of dye, pH and Lemna minor biomass dose. Isotherms and kinetic studies of dye adsorption were performed using equilibrium data. Results: According to the results, a maximum removal efficiency of 98.5% was obtained at pH of 3 and the contact time of 90 min; initial dye concentration 10 mg/L and adsorbent dose 3g/L. The adsorption data was best fitted to the Langmuir isotherm and pseudo-second order kinetic model. Conclusion: The results showed that Lemna minor could be used as a cost-effective adsorbent for removing AB292 dye from textile wastewater efficiently.

Reduction in photosynthetic efficiency of Cladophora glomerata, induced by overlying canopies of Lemna spp.

Science.gov (United States)

Parr, L B; Perkins, R G; Mason, C F

2002-04-01

The duckweeds Lemna minor L. and L. minuscula Herter reduced PSII quantum efficiency (F'q/F'm) of the filamentous green alga Cladophora glomerata Kützing by up to 42% over seven days when floating above mats of C. glomerata in containers. Dissolved oxygen (DO) increased by 23% at 30 degrees C in containers with C. glomerata over controls. But when the water surface in the containers was covered with Lemna spp. floating above C. glomerata, DO was 83% lower at 30 degrees C over seven days than in control samples with no duckweed or alga. Dissolved oxygen was lower beneath a thick mat (1 cm) of either Lemna spp. covering the surface than under a thin layer (single-frond canopy). PAM fluorimetry showed that maximum PSII efficiency (Fv/Fm) of C. glomerata in containers was reduced under a canopy of L. minor by 17% over seven days, and under L. minuscula by 22%. F'q/F'm of C. glomerata in containers exposed to 51 micromol m(-2) s(-1) PPFD decreased under a canopy of L. minor by 16% over seven days, and under L. minuscula by 19% compared to controls. When light response curves were compared, F'q/F'm was significantly reduced under canopies of L. minor at the highest temperatures tested (28 degrees C and 30 degrees C). L. minor significantly reduced relative electron transport rate (rel. ETR) of the controls by up to 71% at 30 degrees C. Relative electron transport rate did not reach light saturation point (Esat) except at 28 degrees and 30 degrees C under mats of L. minor. Whereas the highest rate of production (rel. ETRmax) and Esat increased with temperature in controls, under a canopy of Lemna, decreases were observed. It is suggested that, during periods of high summer temperature and irradiance, shading inhibits oxygenic photosynthesis in mats of C. glomerata beneath canopies of Lenma spp. This results in less oxygen being produced by the C. glomerata (oxygen produced by Lemna spp. is not released into the water), and this may further inhibit the C. glomerata by

Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Amy-Sagers, Cherisse; Reinhardt, Keith; Larson, Danelle M., E-mail: danellelarson77@gmail.com

2017-04-15

Highlights: • Sucralose increased leaf area and photosynthetic capacity of Lemna minor. • Sucralose increased δ {sup 13}C of Lemna, indicating substantial uptake and assimilation. • 100 μg/L-fluoxetine decreased Lemna minor growth and asexual reproduction. - Abstract: Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ{sup 13}C) were measured among treatments ranging from 0 to 15000 nmol/L-sucralose and 0–323 nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ {sup 13}C of L. minor at environmentally relevant concentrations. The increase of δ {sup 13}C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor—a mixotrophic plant—can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine

Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor

International Nuclear Information System (INIS)

Amy-Sagers, Cherisse; Reinhardt, Keith; Larson, Danelle M.

2017-01-01

Highlights: • Sucralose increased leaf area and photosynthetic capacity of Lemna minor. • Sucralose increased δ "1"3C of Lemna, indicating substantial uptake and assimilation. • 100 μg/L-fluoxetine decreased Lemna minor growth and asexual reproduction. - Abstract: Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ"1"3C) were measured among treatments ranging from 0 to 15000 nmol/L-sucralose and 0–323 nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ "1"3C of L. minor at environmentally relevant concentrations. The increase of δ "1"3C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor—a mixotrophic plant—can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine significantly

Orthophosphate modulates the phytotoxicity of nano-ZnO to Lemna minor (L.).

Science.gov (United States)

Chen, Xiaolin; O'Halloran, John; Jansen, Marcel A K

2018-03-02

Because of their applications in large numbers of products, Zinc Oxide nanoparticles (nano-ZnO) will inevitably enter into the environment. Nano-ZnO released into the environment will be present in a complex matrix which can cause various chemical and physical transformations and modulate the biological reactivity of these particles. Due to their rapid growth and small size, Lemna minor is recommended by OECD for toxicological testing. Here, we tested how nano-ZnO reactivity is modulated by the suite of macro- and micronutrients that are present in Lemna minor growth media. Specifically, we measured ex situ Reactive Oxygen Species (ROS) formation by nano-ZnO, and subsequent in planta toxicity. The data show how orthophosphate can modulate both ex situ ROS formation, and in planta toxicity. This has ramifications for phytotoxicity testing, which is commonly performed under controlled conditions and on media containing orthophosphate.

Effects of light and phytochrome in heterotrophic growth of Lemna minor L.

NARCIS (Netherlands)

Rombach, J.

1976-01-01

Axenic cultures of Lemna minor L. were grown on a medium containing sugars and amino acids. In continuous darkness the growth rate was one-tenth of the maximum in continuous light. In darkness early death revealed a thiamine deficiency; this

Study of 137Cs absorption by Lemna minor

International Nuclear Information System (INIS)

Bergamini, P.G.; Palmas, G.; Piantelli, F.; Sani, M.; Banditelli, P.; Previtera, M.; Sodi, F.

1979-01-01

Absorption of 137 Cs by the floating aquatic plant Lemna Minor in relation to 137 Cs concentration in the water was measured under controlled conditions of temperature, pH and light. The method used to analyse the results is described. When applied to this study the method shows the influence on 137 Cs absorption of (1) potassium-cesium exchange due to chemical affinity, (2) the natural colony growth of the organism and (3) the effect of light. Concentration factors were determined for these three processes. (author)

The enzymatic and antioxidative stress response of Lemna minor to copper and a chloroacetamide herbicide.

Science.gov (United States)

Obermeier, Michael; Schröder, Christian A; Helmreich, Brigitte; Schröder, Peter

2015-12-01

Lemna minor L., a widely used model plant for toxicity tests has raised interest for its application to phytoremediation due to its rapid growth and ubiquitous occurrence. In rural areas, the pollution of water bodies with heavy metals and agrochemicals poses a problem to surface water quality. Among problematic compounds, heavy metals (copper) and pesticides are frequently found in water bodies. To establish duckweed as a potential plant for phytoremediation, enzymatic and antioxidative stress responses of Lemna minor during exposure to copper and a chloroacetamide herbicide were investigated in laboratory studies. The present study aimed at evaluating growth and the antioxidative and glutathione-dependent enzyme activity of Lemna plants and its performance in a scenario for phytoremediation of copper and a chloroacetamide herbicide. Lemna minor was grown in Steinberg medium under controlled conditions. Plants were treated with CuSO4 (ion conc. 50 and 100 μg/L) and pethoxamide (1.25 and 2.5 μg/L). Measurements following published methods focused on plant growth, oxidative stress, and basic detoxification enzymes. Duckweed proved to survive treatment with the respective concentrations of both pollutants very well. Its growth was inhibited scarcely, and no visible symptoms occurred. On the cellular basis, accumulation of O2(-) and H2O2 were detected, as well as stress reactions of antioxidative enzymes. Duckweed detoxification potential for organic pollutants was high and increased significantly with incubation. Pethoxamide was found to be conjugated with glutathione. Copper was accumulated in the fronds at high levels, and transient oxidative defense reactions were triggered. This work confirms the significance of L. minor for the removal of copper from water and the conjugation of the selective herbicide pethoxamide. Both organic and inorganic xenobiotics induced different trends of enzymatic and antioxidative stress response. The strong increase of stress

Trophic transfer of cadmium from duckweed (Lemna Minor L.) to Tilapia (Oreochromis mossambicus)

NARCIS (Netherlands)

Xue, Yan; Peijnenburg, Willie J G M; Huang, Jin; Wang, Dengjun; Jin, Yan

2018-01-01

The transfer of the toxic heavy metal Cd from duckweed (Lemna minor L.) to the freshwater fish tilapia (Oreochromis mossambicus) was investigated. Concentrations of Cd in different chemical forms in duckweed and in different tissues (gut, edible muscle, and remnants) of tilapia, i.e.,

Ammonia stress on nitrogen metabolism in tolerant aquatic plant-Myriophyllum aquaticum.

Science.gov (United States)

Zhou, Qingyang; Gao, Jingqing; Zhang, Ruimin; Zhang, Ruiqin

2017-09-01

Ammonia has been a major reason of macrophyte decline in the water environment, and ammonium ion toxicity should be seen as universal, even in species frequently labeled as "NH 4 + specialists". To study the effects of high NH 4 + -N stress of ammonium ion nitrogen on tolerant submerged macrophytes and investigate the pathways of nitrogen assimilation in different organisms, Myriophyllum aquaticum was selected and treated with various concentrations of ammonium ions at different times. Increasing of ammonium concentration leads to an overall increase in incipient ammonia content in leaves and stems of plants. In middle and later stages, high concentrations of NH 4 + ion nitrogen taken up by M. aquaticum decreased, whereas the content of NO 3 - ion nitrogen increased. Moreover, in M. aquaticum, the activities of the enzymes nitrate reductase, glutamine synthetase and asparagine synthetase changed remarkably in the process of alleviating NH 4 + toxicity and deficiency. The results of the present study may support the studies on detoxification of high ammonium ion content in NH 4 + -tolerant submerged macrophytes and exploration of tissue-specific expression systems. Copyright © 2017. Published by Elsevier Inc.

Expression of H5 hemagglutinin vaccine antigen in common duckweed (Lemna minor) protects against H5N1 high pathogenicity avian influenza virus challenge in immunized chickens.

Science.gov (United States)

Bertran, Kateri; Thomas, Colleen; Guo, Xuan; Bublot, Michel; Pritchard, Nikki; Regan, Jeffrey T; Cox, Kevin M; Gasdaska, John R; Dickey, Lynn F; Kapczynski, Darrell R; Swayne, David E

2015-07-09

A synthetic hemagglutinin (HA) gene from the highly pathogenic avian influenza (HPAI) virus A/chicken/Indonesia/7/2003 (H5N1) (Indo/03) was expressed in aquatic plant Lemna minor (rLemna-HA). In Experiment 1, efficacy of rLemna-HA was tested on birds immunized with 0.2μg or 2.3 μg HA and challenged with 10(6) mean chicken embryo infectious doses (EID50) of homologous virus strain. Both dosages of rLemna-HA conferred clinical protection and dramatically reduced viral shedding. Almost all the birds immunized with either dosage of rLemna-HA elicited HA antibody titers against Indo/03 antigen, suggesting an association between levels of anti-Indo/03 antibodies and protection. In Experiment 2, efficacy of rLemna-HA was tested on birds immunized with 0.9 μg or 2.2 μg HA and challenged with 10(6) EID50 of heterologous H5N1 virus strains A/chicken/Vietnam/NCVD-421/2010 (VN/10) or A/chicken/West Java/PWT-WIJ/2006 (PWT/06). Birds challenged with VN/10 exhibited 100% survival regardless of immunization dosage, while birds challenged with PWT/06 had 50% and 30% mortality at 0.9 μg HA and 2.2 μg HA, respectively. For each challenge virus, viral shedding titers from 2.2 μg HA vaccinated birds were significantly lower than those from 0.9μg HA vaccinated birds, and titers from both immunized groups were in turn significantly lower than those from sham vaccinated birds. Even if immunized birds elicited HA titers against the vaccine antigen Indo/03, only the groups challenged with VN/10 developed humoral immunity against the challenge antigen. None (rLemna-HA 0.9 μg HA) and 40% (rLemna-HA 2.2 μg HA) of the immunized birds challenged with PWT/06 elicited pre-challenge antibody titers, respectively. In conclusion, Lemna-expressed HA demonstrated complete protective immunity against homologous challenge and suboptimal protection against heterologous challenge, the latter being similar to results from inactivated whole virus vaccines. Transgenic duckweed-derived HA could be a

Apport du traitement d'images dans le suivi de l'influence des teneurs en nutriments sur la croissance des lentilles d'eau (Lemna minor

Directory of Open Access Journals (Sweden)

Tangou, TT.

2014-01-01

Full Text Available Contribution of image processing in monitoring the influence of nutrients on the growth of duckweed (Lemna minor. The growth of duckweed (Lemna minor is an important component in the treatment process in wastewater floating macrophyte ponds. An excess or shortage of this biomass may be responsible for the dysfunction of such ponds. Modeling these duckweed ponds through mass balances based on Petersen's matrix may be helpful in facilitating the optimal management of such facilities. This study sought to assess the efficiency of digital image processing in the growth monitoring of Lemna minor under different concentrations of nitrogen and phosphorus. The experiments were carried out in a growth chamber (phytotron using an experimental pilot involving initial fresh Lemna minor biomass (1 g, nitrogen and phosphorus concentrations varying between 5 and 64 mg N-NH4+·l-1, and 1 and 24 mg P-PO43-·-1, respectively. Digital image processing was achieved in addition to gravimetric methods (fresh weight and/or dry weight. Our results showed that the image processing method allowed a continuous and non-destructive monitoring of duckweed biomass. The growth of Lemna minor progressively decreased when nitrogen and phosphorus concentrations were greater than 16 mg N-NH4+·l-1 and 6 mg P-PO43-·-1. The maximum growth rates μmax were of the order of 0.07 d-1. The kinetic constants KS and KI were respectively 3.83 mg·l-1 and 204 mg·l-1 for nitrogen, and 1.26 mg·l-1 and 13.3 mg·l-1 for phosphorus. Such results are interesting as they could contribute to the optimal management of Lemna minor and the modeling of biological reactors.

Possible ecological risk of two pharmaceuticals diclofenac andparacetamol demonstrated on a model plant Lemna minor

Czech Academy of Sciences Publication Activity Database

Kummerová, M.; Zezulka, Š.; Babula, P.; Tříska, Jan

2016-01-01

Roč. 302, jan (2016), s. 351-361 ISSN 0304-3894 Institutional support: RVO:67179843 Keywords : Antioxidant mechanism * Diclofenac * Lemna minor * Oxidative stress * Paracetamol Subject RIV: EH - Ecology, Behaviour Impact factor: 6.065, year: 2016

Toxicity of sodium chloride and methyl parathion on the macrophyte Lemna minor (Linnaeus, 1753 with respect to frond number and chlorophyll

Directory of Open Access Journals (Sweden)

Erlei Cassiano Keppeler

2009-09-01

Full Text Available Duckweed, Lemna minor L., is a suitable plant model for toxicity evaluation of many contaminants due to its small size and rapid growth. Methyl parathion is a toxic compound which is utilized to eliminate aquatic insect larvae, among other purposes. Its toxicity was evaluated with the use of L. minor in this study. Methyl parathion was added to Hoagland’s nutrient medium at concentrations of 0, 8, 16, 22, 28 and 32mg.L–1. Lemna minor is used as a tool in evaluating chemical test products for toxic effects. The sensitivity of Lemna to sodium chloride, the reference substance, at concentrations of 0, 2, 4, 6, 7 and 8 g.L–1, was determined for comparison and resulted in an IC50 of 6.87g.L–1. Methyl parathion in L. minor showed an IC50 of 49.48mg.L–1.

Treatment of wastewater by lemna minor

International Nuclear Information System (INIS)

Iram, S.; Zahra, A.

2012-01-01

The aim of the present study was to study the performance of bio-treatment ponds after one year of functioning at National Agricultural Research Center, Islamabad, Pakistan. The physical parameters (colour, pH, EC, TDS, turbidity) and chemical parameters (Zn, Cu, Cd, Ni, Mn, Fe and Pb) are with in the limits which are not sub-lethal for fish rearing. Lemna accumulates higher concentration of heavy metals as compared to wastewater and best for phyto remediation purpose. The treated wastewater is currently used for rearing of fish and irrigation of crops and plants. The plants around the bio-treatment ponds are healthy, green and showing enough production. The present investigation indicates that in future it would be possible to construct bio-treatment ponds in polluted areas of Pakistan. (author)

Toxic Effect of Bispyribac-sodium and Cu^2+ on Lemna Minor%双草醚和Cu对浮萍的毒性效应

Institute of Scientific and Technical Information of China (English)

郑丽英

2012-01-01

The single toxic and combined toxic effects of Cu^2+ and bispyribac-sodium on Lemna minor were studied.The results showed that Cu2+ could stimulate the growth of Lemna minor and affect on the content of chlorophyll when the concentration of Cu^2+ was below 0.2 mg/L.With the increasing of the treatment concentration of Cu^2+,the growth rate of Lemna minor decreased.When its concentration was more than 0.4 mg/L,the growth of Lemna minor and the content of chlorophyll would be significantly affected.When the concentration of bispyribac-sodium was beyond 0.02 mg/L,Lemna minor's growth was obviously inhibited.The joint toxicity of Cu2+ and bispyribac-sodium would inhibit the growth of Lemna minor in concentration 1:1,and the toxicity of combined pollution is obviously greater than those of single pollution.%应用水培实验方法,研究了重金属铜和除草剂双草醚对浮萍的单一毒性和联合毒性效应。结果表明：当Cu^2＋浓度小于0.2 mg/L,可促进浮萍生长;当浓度达到0.4 mg/L时对浮萍生长产生毒害。双草醚浓度高于0.02 mg/L时,对浮萍生长有显著的抑制作用。相同浓度的Cu2＋和双草醚按1∶1等体积混合时明显抑制浮萍生长,且浓度增加,对浮萍生长的毒害效应也逐步增强,叶绿素a的含量明显下降。复合污染对浮萍生长的影响明显大于单一污染,表现为协同作用。

SIZINTI SUYUNUN ARITIMI İÇİN SU MERCİMEKLERİ KARIŞIMININ KULLANILMASI: I. NUTRİENTLER

Directory of Open Access Journals (Sweden)

Murat Topal

2012-08-01

Full Text Available Bu çalışmada, sızıntı suyu arıtımı için Lemna gibba L., Lemna minor L., Spirodela polyrrhiza ve Wolffia arrhiza’dan oluşan su mercimekleri karışımı kullanılmış ve bitkili kesikli sistemde nutrientlerin değişimleri araştırılmıştır. Çalışmada, NH4+-N, NO2--N, NO3—N ve O-PO43- konsantrasyonları tespit edilmiştir. Deneysel çalışmalar 2 farklı derinlikte (5 ve 10 cm ve farklı hidrolik bekletme sürelerinde gerçekleştirilmiştir. En yüksek NH4+-N giderim verimi (%75,3, 5 cm derinlikteki reaktörde 9. günde tespit edilmiştir. NO2- -N ve NO3- -N konsantrasyonlarında herhangi bir giderim olmadığı gözlenmiştir. En yüksek O-PO43- giderim verimi 5 cm derinlikteki reaktörde %44,6 olarak tespit edilmiştir.

Comprehensive evaluation of nitrogen removal rate and biomass, ethanol, and methane production yields by combination of four major duckweeds and three types of wastewater effluent.

Science.gov (United States)

Toyama, Tadashi; Hanaoka, Tsubasa; Tanaka, Yasuhiro; Morikawa, Masaaki; Mori, Kazuhiro

2018-02-01

To assess the potential of duckweeds as agents for nitrogen removal and biofuel feedstocks, Spirodela polyrhiza, Lemna minor, Lemna gibba, and Landoltia punctata were cultured in effluents of municipal wastewater, swine wastewater, or anaerobic digestion for 4 days. Total dissolved inorganic nitrogen (T-DIN) of 20-50 mg/L in effluents was effectively removed by inoculating with 0.3-1.0 g/L duckweeds. S. polyrhiza showed the highest nitrogen removal (2.0-10.8 mg T-DIN/L/day) and biomass production (52.6-70.3 mg d.w./L/day) rates in all the three effluents. Ethanol and methane were produced from duckweed biomass grown in each effluent. S. polyrhiza and L. punctata biomass showed higher ethanol (0.168-0.191, 0.166-0.172 and 0.174-0.191 g-ethanol/g-biomass, respectively) and methane (340-413 and 343-408 NL CH 4 /kg VS, respectively) production potentials than the others, which is related to their higher carbon and starch contents and calorific values. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Toxicological implications of selenium nanoparticles with different coatings along with Se4+ on Lemna minor.

Science.gov (United States)

Tarrahi, Roshanak; Khataee, Alireza; Movafeghi, Ali; Rezanejad, Farkhondeh; Gohari, Gholamreza

2017-08-01

Nanoparticles have potential high risks for living organisms in the environment due to their specific qualities and their easy access. In the present study, selenium nanoparticles (Se NPs) with two different coatings (l-cysteine and tannic acid) were synthesized. The characteristics of particles were analyzed using XRD, FT-IR and SEM. The impact of the nanoparticles besides Se 4+ , on the aquatic higher plant Lemna minor was evaluated and compared. Entrance of l-cysteine and tannic acid capped Se NPs in the roots of Lemna minor was proved by TEM and fluorescence microscopy. Adverse effects of mentioned NPs and differences of these effects from those by sodium selenite as the ionic form were assessed by a range of biophysicochemical tests. Altogether, the results asserted that Lemna minor was notably poisoned by both capped Se NPs and Se 4+ . Thus, growth and photosynthetic pigments were decreased while lipid peroxidation along with total phenol and flavonoid contents were raised. Eventually some changes in enzymatic activities were presented. To sum up the consequences, it can be concluded that all changes occurred due to the plant defense system especially in order to remove reactive oxygen species (ROS) and possible phytotoxicity originated by l- cysteine and tannic acid capped Se NPs in addition to Se 4+ . The influence of tannic acid capped Se NPs after sodium selenite is stronger by the means of antioxidant enzymes activity in comparison with l-cysteine capped Se NPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Study of /sup 137/Cs absorption by Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Bergamini, P G; Palmas, G; Piantelli, F; Sani, M [Siena Univ. (Italy). Ist. di Fisica; Banditelli, P; Previtera, M; Sodi, F

1979-09-01

Absorption of /sup 137/Cs by the floating aquatic plant Lemna minor in relation to /sup 137/Cs concentration in the water was measured under controlled conditions of temperature, pH and light. The method used to analyse the results is described. When applied to this study the method shows the influence on /sup 137/Cs absorption of (1) potassium-cesium exchange due to chemical affinity, (2) the natural colony growth of the organism and (3) the effect of light. Concentration factors were determined for these three processes.

Toxicity of sodium chloride and methyl parathion on the macrophyte Lemna minor (Linnaeus, 1753 with respect to frond number and chlorophyll

Directory of Open Access Journals (Sweden)

Erlei Cassiano Keppeler

2009-06-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2009v22n3p27 Duckweed, Lemna minor L., is a suitable plant model for toxicity evaluation of many contaminants due to its small size and rapid growth. Methyl parathion is a toxic compound which is utilized to eliminate aquatic insect larvae, among other purposes. Its toxicity was evaluated with the use of L. minor in this study. Methyl parathion was added to Hoagland’s nutrient medium at concentrations of 0, 8, 16, 22, 28 and 32mg.L–1. Lemna minor is used as a tool in evaluating chemical test products for toxic effects. The sensitivity of Lemna to sodium chloride, the reference substance, at concentrations of 0, 2, 4, 6, 7 and 8 g.L–1, was determined for comparison and resulted in an IC50 of 6.87g.L–1. Methyl parathion in L. minor showed an IC50 of 49.48mg.L–1.

Bioremoval of cadmium by lemna minor in different aquatic conditions

Energy Technology Data Exchange (ETDEWEB)

Uysal, Yagmur [Dept. of Environmental Engineering, Kahramanmaras Sutcu Imam University, Kahramanmaras (Turkey); Taner, Fadime [Dept. of Environmental Engineering, Mersin University, Mersin (Turkey)

2010-04-15

This study was undertaken to determine the cadmium removal efficiency of Lemna minor when it was used for treatment of wastewater having different characteristics, i. e., pH, temperature and cadmium concentration. Plants were cultivated in different pH solutions (4.5-8.0) and temperatures (15-35 C) in the presence of cadmium (0.1-10.0 mg/L) for 168 h. The amount of biomass obtained in the study period, the concentrations of cadmium in the tissues and in the media and net uptake of cadmium by Lemna have been determined for each condition. The percentages of cadmium uptake (PMU) and bioconcentration factors (BCF) were also calculated. The highest accumulation was obtained for the highest cadmium concentration of 10.0 mg Cd/L as 11.668 mg Cd/g at pH 6.0, and as 38.650 mg Cd/g at 35 C and pH 5.0. The cadmium accumulation gradually increased with initial concentration of the medium, but the opposite trend was observed for the PMU. However, the maximum PMU was obtained as 52.2% in the solution with the lowest concentration of 0.1 mg Cd/L. A mathematical model was used to describe the cadmium uptake and the equation obtained was seen to fit the experimental data very well. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

Effects of growth, development and reproduction of Tenebrio molitor by feeding Lemna minor%饲喂浮萍对黄粉虫生长发育及繁殖的影响

Institute of Scientific and Technical Information of China (English)

王清春; 刘玉升; 方加兴

2017-01-01

为探索浮萍Lemna minor生物质利用新途径,解决浮萍在污水中引起的二次污染现象,本研究利用黄粉虫Tenebrio molitor L食性杂,易饲养,可转化利用多种有机生物质资源的的特性,将浮萍烘干、磨碎后,与麦麸配制成50％浮萍∶50％麦麸,60％浮萍∶40％麦麸,70％浮萍∶30％麦麸,80％浮萍∶20％麦麸不同比例的混合饲料(加水使饲料含水量保持为18％)来饲养黄粉虫幼虫(以纯麦麸为对照组);同时以浮萍替代豆饼作为添加料,按照白菜∶麦麸∶浮萍=10∶4∶1做成混合饲料饲养成虫,来研究浮萍对黄粉虫生长发育及繁殖的影响.结果显示:与纯麦麸相比,幼虫试验中各处理组的生物量增长率、饲料利用率均降低,死亡率增高,而饲喂“50％浮萍∶50％麦麸”饲料的黄粉虫幼虫的各指标与对照组差异不显著,为最佳浮萍饲料配比;在成虫试验中,以浮萍为添加料的成虫单雌产卵量为586.33±6.84粒,成虫寿命为105.5 ±1.43 d,均显著高于以豆饼为添加料的对照组.本研究对利用黄粉虫转化处理浮萍的效果做出了初步评价,即黄粉虫取食转化浮萍是可行的,为浮萍的生物质利用提供参考.%In order to explore the utilization of Lemna minor biomass in new ways,and to solve the second pollution phenomenon caused by it in wastewater.In the study,we make use of some characteristics of Tenebrio molitor L.,such as omnivorous,easy to breed and can utilizate of a variety of organic biomass resources,to transform and utilize Lemna minor.First,we dried Lemna minor to constant weight and mixed with wheat bran in different proportions (add water to keep the water content of these artificial diet at 18％):"50％ Lemna minor∶ 50％wheat bran","60％ Lemna minor:40％ wheat bran","70％ Lemna minor∶30％ wheat bran","80％ Lemna minor∶20％ wheat bran" to feed Tenebrio molitor larvae (pure wheat bran as the control group);Then,we use Lemna

The first draft genome of the aquatic model plant Lemna minor opens the route for future stress physiology research and biotechnological applications.

Science.gov (United States)

Van Hoeck, Arne; Horemans, Nele; Monsieurs, Pieter; Cao, Hieu Xuan; Vandenhove, Hildegarde; Blust, Ronny

2015-01-01

Freshwater duckweed, comprising the smallest, fastest growing and simplest macrophytes has various applications in agriculture, phytoremediation and energy production. Lemna minor, the so-called common duckweed, is a model system of these aquatic plants for ecotoxicological bioassays, genetic transformation tools and industrial applications. Given the ecotoxic relevance and high potential for biomass production, whole-genome information of this cosmopolitan duckweed is needed. The 472 Mbp assembly of the L. minor genome (2n = 40; estimated 481 Mbp; 98.1 %) contains 22,382 protein-coding genes and 61.5 % repetitive sequences. The repeat content explains 94.5 % of the genome size difference in comparison with the greater duckweed, Spirodela polyrhiza (2n = 40; 158 Mbp; 19,623 protein-coding genes; and 15.79 % repetitive sequences). Comparison of proteins from other monocot plants, protein ortholog identification, OrthoMCL, suggests 1356 duckweed-specific groups (3367 proteins, 15.0 % total L. minor proteins) and 795 Lemna-specific groups (2897 proteins, 12.9 % total L. minor proteins). Interestingly, proteins involved in biosynthetic processes in response to various stimuli and hydrolase activities are enriched in the Lemna proteome in comparison with the Spirodela proteome. The genome sequence and annotation of L. minor protein-coding genes provide new insights in biological understanding and biomass production applications of Lemna species.

Production of biogas from Azolla pinnata R. Br. and Lemna minor L. : effect of heavy metal contamination

Energy Technology Data Exchange (ETDEWEB)

Jain, S K; Gujral, G S; Jha, N K; Vasudevan, P [Indian Inst. of Tech., New Delhi (India)

1992-01-01

The absorption of iron, copper, cadmium, nickel, lead, zinc, manganese and cobalt by Azolla pinnata R.Br and Lemna minor L., and subsequent utilization of this biomass for production of biogas (methane), have been investigated. Iron or manganese did not have any toxic effect on the anaerobic fermentation of Azolla and Lemna, while copper, cobalt, lead and zinc showed toxicity. At low concentrations cadmium and nickel showed a favourable effect on the rate of biogas production and its methane content, but with increase in concentrations,rate of biogas production and methane content decreased. However, although there was this decrease in biogas production and methane content, the methane content of biogas was still higher than that which was obtained from non-contaminated biomass. (author).

Duckweed does not improve the efficiency of municipal wastewater treatment in lemna system plants / Rzęsa nie poprawia efektywności oczyszczania ścieków komunalnych w oczyszczalniach typu Lemna System

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Ozimek Teresa

2015-09-01

Full Text Available Badania prowadzono w trzech czyszczalniach hydrofi towych z powierzchniowym przepływem ścieków typu Lemna System, zbudowanych według projektu Lemna Corporation. Składają się one ze stawu napowietrzanego i stawu rzęsowego wyposażonego w system barier mających na celu równomierne rozmieszczenie roślin. Stawy poprzedzone są osadnikiem wstępnym. Według projektantów odpowiednia praca tych oczyszczalni związana jest z występowaniem rzęsy na powierzchni stawu rzęsowego. Badano efektywność oczyszczania ścieków komunalnych w trzech oczyszczalniach Lemna System usytuowanych w centralnej Polsce ze szczególnym uwzględnieniem roli stawu rzęsowego i samej rzęsy. Oczyszczalnie różniły się między sobą występowaniem rzęsy. W dwóch z nich (w Rakowie i Bąkowcu w trakcie całego okresu badań rzęsa nie występowała, natomiast w trzeciej (w Falęcinie Starym w okresie wegetacyjnym pokrywała do 90%.powierzchni stawu. Efektywność oczyszczanie ścieków nie różniła się w oczyszczalni z rzęsą i bez rzęsy. Rzęsa nie wpływała istotnie na efektywność oczyszczania ścieków. We wszystkich oczyszczalniach główną rolę w redukcji zanieczyszczeń odgrywał staw napowietrzany

Comparative sensitivity of five species of macrophytes and six species of algae to atrazine, metribuzin, alachlor, and metolachlor

Science.gov (United States)

Fairchild, James F.; Ruessler, Shane; Carlson, A. Ron

1998-01-01

This study determined the relative sensitivity of five species of aquatic macrophytes and six species of algae to four commonly used herbicides (atrazine, metribuzin, alachlor, and metolachlor). Toxicity tests consisted of 96-h (duckweed and algae) or 14-d (submerged macrophytes) static exposures. The triazine herbicides (atrazine and metribuzin) were significantly more toxic to aquatic plants than were the acetanilide herbicides (alachlor and metolachlor). Toxicity studies ranked metribuzin > atrazine > alachlor > metolachlor in decreasing order of overall toxicity to aquatic plants. Relative sensitivities of macrophytes to these herbicides decreased in the order of Ceratophyllum > Najas > Elodea > Lemna > Myriophyllum. Relative sensitivities of algae to herbicides decreased in the order of Selenastrum > Chlorella > Chlamydomonas > Microcystis > Scenedesmus > Anabaena. Algae and macrophytes were of similar overall sensitivities to herbicides. Data indicated that Selenastrum, a commonly tested green alga, was generally more sensitive compared to other plant species. Lemna minor, a commonly tested floating vascular plant, was of intermediate sensitivity, and was fivefold less sensitive than Ceratophyllum, which was the most sensitive species tested. The results indicated that no species was consistently most sensitive, and that a suite of aquatic plant test species may be needed to perform accurate risk assessments of herbicides.

Effect of electromagnetic fields on duckweed (lemna minor) and alga (chlorella kessleri)

International Nuclear Information System (INIS)

Tkalec, M.; Malaric, K.; Malaric, R.; Vidakovic-Cifrek, Z.; Pevalek-Kozlina, B.

2005-01-01

Electricity produces extremely low frequency fields (50-60 Hz) while various kinds of radiofrequency fields (10 MHz-300 GHz) are used to transmit information (TV, radio, mobile phones and satellite communications). Duckweed (Lemna minor) and green algae (Chlorella kessleri) were exposed to the magnetic field of 50 Hz in a Helmholtz coil, to an electric field of 50 Hz between two parallel circle electrodes, and to electromagnetic fields of 400 and 900 MHz in a Gigahertz Transversal Electromagnetic Mode cell. The relative growth of Lemna minor exposed to extremely low frequency alternating magnetic field of 50 Hz (1 mT) for 24 hours was slightly reduced at the beginning of the experiment while a 50 Hz electric field (25 kV/m) slightly reduced its growth during the second week of the experiment. Radio frequencies of 400 and 900 MHz (23 V/m) applied for two hours decreased the duckweed growth after the third day, but only 900 MHz affected it significantly. The rate of photosynthesis in green algae increased after exposure to the magnetic field of 50 Hz, but decreased after exposure to the electric field of 50 Hz. Radio frequencies of 400 and 900 MHz generally increased its rate of photosynthesis.(author)

The Minimization of Organic and Metallic Industrial Waste Via LEMNA MINOR Concentration

Science.gov (United States)

1992-12-30

from municipal and industrial waste waters. Duckweed is a floating, widespread and fast-growing plant. It is smal, 3asy to cultivate and highly sensitive...and Cairns, J. Jr., "Accumulation and Depuration of Metals by Duckweed (Lemna perpusilla)," Ecotoxicology and Environmental Safety, 5, 87-96, 1981...to separate substances of different densities. calla: a plant of the arum family, native to South Africa, but cultivated in the United States, and

Enhanced plant regeneration in lemna minor by amino acids

International Nuclear Information System (INIS)

Yang, L.; Han, H.; Zhou, K.; Ren, C.; Zhu, Y.

2014-01-01

In present study we investigated the effects of different L-amino acids on the plant regeneration from callus of Lemna minor, and established an efficient protocol. Among the 20 L-amino acids, only L-Ser and L-Gly showed significant improving effect, with the optimal concentration being 1 mM and 1.5 mM, respectively. A regeneration frequency of 46% was observed when the callus transferred to the regeneration medium with addition of 1 mM L-Ser for 11 days. After 26 days of cultivation, the frond regeneration achieved 100% and 94% for 1 mM L-Ser and 1.5 mM L-Gly treatment, respectively. (author)

SIZINTI SUYUNUN ARITIMI İÇİN SU MERCİMEKLERİ KARIŞIMININ KULLANILMASI: II. DİĞER PARAMETRELER

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Murat Topal

2012-08-01

Full Text Available Bu çalışmada, sızıntı suyu arıtımı için Lemna gibba L., Lemna minor L., Spirodela polyrrhiza ve Wolffia arrhiza’dan oluşan su mercimekleri karışımı kullanılmış ve bitkili kesikli sistemde KOİ, pH ve elektriksel iletkenlik değişimleri araştırılmıştır. Deneysel çalışmalar, 4 adet reaktörde oda sıcaklığında gerçekleştirilmiştir. En yüksek KOİ giderim verimi, 5 ve 10 cm derinlikteki reaktörlerde sırasıyla %62,2 ve %60,1 olarak tespit edilmiştir. Başlangıçta 7,91 değerinde olan pH, farklı hidrolik bekletme sürelerinde 7,91-8,49 arasında olmuştur. Başlangıçta 5,59 mS/cm değerinde olan elektriksel iletkenlik, en yüksek 9,46 mS/cm değerine ulaşmıştır.

LA LENTEJA DE AGUA (LEMNA MINOR L.: UNA PLANTA ACUÁTICA PROMISORIA*

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María del Pilar Arroyave

Full Text Available Se describen las principales características morfológicas y ecológicas de la planta acuática Lemna minor L., al igual que la utilización que tiene como complemento alimenticio para animales domésticos y en labores de fitorremediación, por su capacidad de absorber nutrientes y contaminantes de los ecosistemas acuáticos. Asimismo se discute su potencial como una especie adecuada para realizar ensayos de fitotoxicidad.

Production and characterization of Lemna minor bio-char and its catalytic application for biogas reforming

International Nuclear Information System (INIS)

Muradov, Nazim; Fidalgo, Beatriz; Gujar, Amit C.; Garceau, Nathaniel; T-Raissi, Ali

2012-01-01

Pyrolysis of fast-growing aquatic biomass - Lemna minor (commonly known as duckweed) with the emphasis on production, characterization and catalytic application of bio-char is reported in this paper. The yield of bio-char was determined as a function of L. minor pyrolysis temperature and sweep gas flow rate. It was found that the pore development during L. minor pyrolysis was not significant and the changes in the reaction conditions (temperature and sweep gas flow rate) did not alter markedly the textural characteristics and BET surface area of the bio-char produced. Thermogravimetric/differential thermogravimetric (TG/DTG) analyses of L. minor and different bio-char samples in inert (helium) and oxidative (air) media showed substantial differences in their TG/DTG patterns. A comparison of scanning electron micrographs (SEM) of L. minor, bio-char and ash indicated that the basic structural features of L. minor remained intact and were not affected by thermolysis. The inorganic ash content of L. minor derived bio-char is significantly higher than that of typical terrestrial (plant) biomass. The energy dispersive spectroscopic (EDS) analysis of L. minor ash showed that it mostly consisted of silica, and small quantities of Na, K and Ca compounds. The treatment of bio-char with CO 2 at 800 °C increased its BET surface area. It was found that CO 2 -treated bio-char exhibited appreciable initial catalytic activity in biogas reforming. -- Highlights: ► New data on characterization of bio-chars derived from Lemna minor are presented. ► Effect of pyrolysis operational parameters on bio-char properties is determined. ► Basic skeletal structure of Lemna minor leaflets does not change during pyrolysis. ► Bio-chars show an appreciable initial catalytic activity for biogas reforming.

Effect of gamma-radiation on demographic and morphometric parameters of laboratory population of duckweed Lemna minor

International Nuclear Information System (INIS)

Rasskazova, M.M.; Berestina, A.V.

2015-01-01

After effect of chronic gamma-exposition on Lemna minor plants, significantly decreases the specific rate of population growth, increases the process of frond's dying-off. The chronic exposition with radiation intensity 5,0 Gy/hour induces roots growth and significantly increased percent of damaged fronds. (authors)

Phytotoxicity Studies of Metsulfuron-methyl, Terbuthylazine and 3, 5 -Dichlorophenol by Duckweed (Lemna minor L. Test

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M. Abbaspoor

2016-06-01

Full Text Available Introduction: From the floating aquatic plant species, duckweed (i.e., Lemna sp. is perhaps the most commonly used in toxicity testing. As its name implies, it is a staple in the summer diet of ducks as well as other aquatic organisms. Actually, “duckweed” can refer to both Lemna sp. and Spirodela sp. (greater duckweed, although, it is usually associated with Lemna minor. The Lemnaceae (duckweeds are cosmopolitan free-floating aquatic monocotyledonous angiosperms that commonly occur in fresh and brackish stagnant ponds and sluggish streams, mostly in tropical regions but also as far north as 60° and as far south as 40° latitude. Duckweeds are vascular floating non-rooted aquatic plants with a reduced root system and lack stems and true leaves. It has been speculated that the roots serve as anchors to keep the fronds right side up and to form the tangled masses, which are of some importance in dispersal and protection from water movement. They can reproduce both sexually and asexually, however, asexual vegetative reproduction is the more commonly occurring mode and, under laboratory conditions, a doubling in frond number and surface area covered can occur every 1.5–2 days. Duckweed can rapidly colonize open surface waters and develop a large biomass. These characteristics, plus its ability to accumulate inorganic ions favor it for use in wastewater treatment systems and makes duckweed an ideal model for studies on the metabolism of pollutants by aquatic macrophytes as well as for toxicity studies. They are very sensitive to many substances and are already used as convenient test organisms for toxicity evaluation of a number of pollutants including industrial and wastewater effluents, herbicides, heavy metals, surfactants and other common chemicals. The typical test end points are changes in the growth rate (expressed as frond production, fresh and dry weight and frond area and changes in pigment content. For a few years biotests with

Growth inhibition and recovery of Lemna gibba after pulse exposure to sulfonylurea herbicides

DEFF Research Database (Denmark)

Rosenkrantz, Rikke Tjørnhøj; Baun, Anders; Kusk, Kresten Ole

2013-01-01

The exposure of non-target aquatic organisms to pesticides often happens as short-term, high exposure events (pulses) and effects of these must be addressed in the current regulation in the EU. It is, however, questionable whether the effects of pulse exposures are adequately covered by the stand...... tests. The approach of this study enables experimentally based comparisons between observations of effects between the two exposure regimes. We propose that results obtained in this way be applied in effect assessments for intermittent releases....

A NEW APPROACH FOR CULTURING LEMNA MINOR (DUCKWEED) AND STANDARDIZED METHOD FOR USING ATRAZINE AS A REFERENCE TOXICANT

Science.gov (United States)

Lemna minor (Duckweed) is commonly used in aquatic toxicity investigations. Methods for culturing and testing with reference toxicants, such as atrazine, are somewhat variable among researchers. Our goal was to develop standardized methods of culturing and testing for use with L....

Model for Stress-induced Protein Degradation in Lemna minor1

Science.gov (United States)

Cooke, Robert J.; Roberts, Keith; Davies, David D.

1980-01-01

Transfer of Lemna minor fronds to adverse or stress conditions produces a large increase in the rate of protein degradation. Cycloheximide partially inhibits stress-induced protein degradation and also partially inhibits the protein degradation which occurs in the absence of stress. The increased protein degradation does not appear to be due to an increase in activity of soluble proteolytic enzymes. Biochemical evidence indicates that stress, perhaps acting via hormones, affects the permeability of certain membranes, particularly the tonoplast. A general model for stress-induced protein degradation is presented in which changes in membrane properties allow vacuolar proteolytic enzymes increased access to cytoplasmic proteins. PMID:16661588

Lead pollution: poisonous effects on plants. [Phalanis canariensis; Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Fiussello, N

1973-01-01

Lead alkyl additives in motor gasoline emitted into the atmosphere are responsible for the high levels of lead in soil and plants near roads. The A has tested the poisonousness of lead salts against the germination and growth of wheat, oats and Phalaris canariensis. Concentrations of 10-/sup 2/ M lead nitrate inhibit, in part, wheat germination and totally oats and P. - canariensis germination. In sand cultures with a lead content of 200 p.p.m. there is a diminution of fresh weight, of dry weight and of the chlorophyll content. Water plants (Lemna minor) are remarkably damaged by lead nitrate (200 p.p.m. conc.). 5 references.

Acute and chronic toxicity testing of bisphenol A with aquatic invertebrates and plants.

Science.gov (United States)

Mihaich, Ellen M; Friederich, Urs; Caspers, Norbert; Hall, A Tilghman; Klecka, Gary M; Dimond, Stephen S; Staples, Charles A; Ortego, Lisa S; Hentges, Steven G

2009-07-01

Bisphenol A (BPA, 4,4'-isopropylidine diphenol) is a commercially important chemical used primarily as an intermediate in the production of polycarbonate plastic and epoxy resins. Extensive effect data are currently available, including long-term studies with BPA on fish, amphibians, crustaceans, and mollusks. The aim of this study was to perform additional tests with a number of aquatic invertebrates and an aquatic plant. These studies include acute tests with the midge (Chironomus tentans) and the snail (Marisa cornuarietis), and chronic studies with rotifers (Brachionus calyciflorus), amphipods (Hyalella azteca), and plants (Lemna gibba). The effect data on different aquatic invertebrate and plant species presented in this paper correspond well with the effect and no-effect concentrations (NOECs) available from invertebrate studies in the published literature and are within the range found for other aquatic species tested with BPA.

DNA damage and repair in Stylonychia lemnae (Ciliata, Protozoa)

International Nuclear Information System (INIS)

Ammermann, D.

1988-01-01

Irradiation with X rays, UV irradiation after incorporation of bromodeoxyuridine (BU) into the DNA, and cis-platinum (cis-Pt) treatment each cause the loss of micronuclei of Stylonychia lemnae while the macronuclei are not severely affected. The abilities of both nuclei to repair DNA were investigated. Unscheduled DNA synthesis could not be demonstrated after X-ray irradiation, but it was found after treatment with BU/UV and cis-Pt in macro- and micronuclei. The extent of the repair process in the micro- and macronuclei was alike, as indicated by grain counts of [6- 3 H]thymidine-treated cells. One reason for the different sensitivity of both nuclei to DNA-damaging treatment may be the different number of gene copies in the macro- and micronuclei

Inhibition of sulfate uptake by Lemna minor 1. during aeration with sublethal concentrations of SO/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Schaerer, M; Brunold, C; Erismann, K H

1975-01-01

The sulfate uptake of Lemna minor l. is very rapidly inhibited by SO/sub 2/-concentrations of 0.15, 0.32 and 0.61 ppM. The sulfate concentration in the plant material is increased. At least 40% of the total sulfur in the organisms originate from SO/sub 2/.

Study of the influence of platinum, palladium and rhodium on duckweed (Lemna minor).

Science.gov (United States)

Bednarova, Ivana; Mikulaskova, Hana; Havelkova, Barbora; Strakova, Lenka; Beklova, Miroslava; Sochor, Jiri; Hynek, David; Adam, Vojtech; Kizek, Rene

2014-01-01

Road traffic pollutants and the residues of cytostatics that are widely used in anti-cancer therapy are a significant sources of platinum group elements (PGE; Pt, Pd and Rh) in environment. These metals can migrate into sewage and thus pollute surface waters. The purpose of our study was to evaluate the effect of PtCl4 on the antioxidant and enzymatic activity of duckweed (Lemna minor), a bioindicator of the aquatic environment. The study was performed using a 7-day conventional test based on the OECD 221 (CSN EN ISO 20079)--Lemna sp. Growth Inhibition Test. We also conducted a microbiotest to analyse the effects of PtC4, PdCl2 and RhCl3 on the morphology and vegetative growth of colonies of this plant and compared their inhibitory effects during the microbiotest. We observed inhibition of colony growth and clear morphological changes. Antioxidant and enzymatic activities increased with platinum doses increased. The 168hEC50 of PtCl4 was 12.16 μM (95% confidence interval = 9.88-14.44) and the 168hEC50 of PdCl2 was 50.39 (95% confidence interval = 23.83-76.96). The greatest inhibition of growth by RhCl3 was observed at 25 μM. The obtained results suggest that L. minor phytotoxicity tests should be widely used in the biomonitoring.

Researchin chronic low-level gamma -irradiation on laboratory populations of Lemna minor

International Nuclear Information System (INIS)

Rasskazova, M.M.; Berestina, A.V.

2012-01-01

Researching carried out on the laboratory population of Lemna minor showed that the chronically γ-irradiated plants significantly reduced specific rate of population growth, accelerating the process of withering away of the fronds. Chronic irradiation with dose of 5,0 mGy/h stimulates the growth of the roots, and irradiation with a capacity of 50 mGy/h significantly increases the percentage of damage fronds. Found out independent of dose effect on the criterion of the number of deaths of individuals in the range of absorbed dose between 0,01 - 1 Gy. (authors)

Myriophyllum aquaticum Constructed Wetland Effectively Removes Nitrogen in Swine Wastewater

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Haishu Sun

2017-10-01

Full Text Available Removal of nitrogen (N is a critical aspect in the functioning of constructed wetlands (CWs, and the N treatment in CWs depends largely on the presence and activity of macrophytes and microorganisms. However, the effects of plants on microorganisms responsible for N removal are poorly understood. In this study, a three-stage surface flow CW was constructed in a pilot-scale within monospecies stands of Myriophyllum aquaticum to treat swine wastewater. Steady-state conditions were achieved throughout the 600-day operating period, and a high (98.3% average ammonia removal efficiency under a N loading rate of 9 kg ha-1 d-1 was observed. To determine whether this high efficiency was associated with the performance of active microbes, the abundance, structure, and interactions of microbial community were compared in the unvegetated and vegetated samples. Real-time quantitative polymerase chain reactions showed the abundances of nitrifying genes (archaeal and bacterial amoA and denitrifying genes (nirS, nirK, and nosZ were increased significantly by M. aquaticum in the sediments, and the strongest effects were observed for the archaeal amoA (218-fold and nirS genes (4620-fold. High-throughput sequencing of microbial 16S rRNA gene amplicons showed that M. aquaticum greatly changed the microbial community, and ammonium oxidizers (Nitrosospira and Nitrososphaera, nitrite-oxidizing bacteria (Nitrospira, and abundant denitrifiers including Rhodoplanes, Bradyrhizobium, and Hyphomicrobium, were enriched significantly in the sediments. The results of a canonical correspondence analysis and Mantle tests indicated that M. aquaticum may shift the sediment microbial community by changing the sediment chemical properties. The enriched nitrifiers and denitrifiers were distributed widely in the vegetated sediments, showing positive ecological associations among themselves and other bacteria based on phylogenetic molecular ecological networks.

Lemna Minor Indicative of Phosphorus Pollution in Panlong River%盘龙江青萍的磷污染指示性研究

Institute of Scientific and Technical Information of China (English)

兰丹; 苏怀; 常玉兰; 李福姗; 张亚楠; 赵宏兵

2016-01-01

Objective] To study the lemna minor indicative of phosphorus pollution in Panlong River.[Methods] Laboratory cultivation and field survey were carried.[Results] In laboratory cultivation condition: lemna minor can grow normally in culture solution with phosphorus concentration of 0.1 mg/L to 15 mg/L.In field survey condition, the phosphorus concentration at each sampling point in Panlong River was 0.07 mg/L to 0.47 mg/L.Distribution of lemna minor: no distribution in upper reaches, slight distribution in middle reaches, more abun-dance in low reaches.[Conclusion] Lemma minor can indicate the water quality above grade II, and water with appearance of lemna minor in-dicates phosphorus pollution.%[目的]判断青萍是否可以作为盘龙江磷污染的指示性生物。[方法]以青萍作为研究对象，研究青萍对磷的耐受程度，分实验室培养和野外调查。[结果]实验室培养条件下，青萍可以在磷浓度0．1～15．0 mg／L的培养液中正常生长。野外调查盘龙江各采样点磷浓度（0．07～0．47 mg／L）的青萍分布情况：上游河段没有出现，中游河段有出现，下游河段多度增加。[结论]青萍至少可以指示2类水以上的水质，有青萍出现的水体已经受到磷污染。

Effect of ionic interaction of chlorode-borate and iodide-borate on their absorption by Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Thellier, M; Ayadi, A; Tromeur, C

1967-11-27

The effect of borate ions on the absorption of chloride and iodide ions by Lemna minor was studied by using the radioactive tracers Cl-36 at 23/sup 0/C with an illumination of 8000 Lux and I-131 at 25.5 C with 600 Lux. The absorbed quantities of the tracer elements were measured with a Geiger counter. The concentrations of sodium chloride solutions tested ranged from 0.055 to 1 mM, those of potassium iodide from 0.04 to 4 mM. While the presence of borate ions in the test solutions of NaCl inhibited the absorption of Cl ions by Lemna minor, only a mild inhibition or none at all was noted in the case of the absorption of I ions. Because of the difference of the cations (sodium in the case of Cl, potassium in the case of I) no direct comparison can be drawn between the absorption of the two halogens. The absorption of I by the plant is thought to proceed by a much simpler mechanism than that of Cl.

THE ROLE OF DUCKWEED (LEMNA MINOR L. IN SECONDARY CLARIFIER TANKS

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Engin Gürtekin

2008-01-01

Full Text Available In this study, the effects of duckweed (Lemna minor L. presence on the effluent water quality and settling characteristics in the secondary clarifier tank of a conventional biological treatment plant were investigated. For this purpose, the performances of the secondary clarifier with and without duckweed were compared. In the secondary clarifier tank with duckweed, COD, BOD5, ammonium and phosphate removal efficiencies were higher by 15, 25, 35 and 45%, respectively. SS concentration of effluent and values of sludge volume index (SVI were the same. The results showed that duckweed contributes to treatment efficiency of conventional biological treatment plant, which reduces the need of tertiary nutrients removal.

Inhibition of phosphorylation and incorporation of thymidine in Duckweed (Lemna minor L. ) by sulfur dioxide and sulfite

Energy Technology Data Exchange (ETDEWEB)

Braendle, R; Stoeckli, B; Erismann, K H

1975-05-15

As there appears to be no thymidine kinase in duckweed (Lemna minor L.), thymidine seems to be phosphorylated by a nucleoside phosphotransferase. Phosphorylation and incorporation are inhibited by sulfur compounds such as sulfur dioxide and sulfite. The data are discussed in relation to the physiological effect of the air pollutant (SO2) on plant life. 12 references, 2 tables.

Rice field flora and vegetation in the provinces of Valencia and Tarragona

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Carretero, J. L.

1988-01-01

Full Text Available Twenty nine emergent and twenty floating or submerged taxa , were found in the rice fields in Valencia and Tarragona provinces. Eleven of the se taxa, all them emergent, are alien Of introduced ones. Echinochloa oryzoides and E. oryzicola are the most important in both areas, together with Cyperus difformis and Echinochloa hispidula in Valencia. The remaining thirty eight taxa belong to the native flora. There are predominantly the emergent Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli and Paspalum distichum; the floating Lemna minor and L. gibba; the submersed Potamogeton nodosus; Zannichellia palustris and Najas minor; and the macroscopical algae Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme, Spirogyra spp., Pithophora oedogania and Hydrodictyon reticulatum. The flora evolution during the last years is analyzed and the present weed communities are studied. The contribution of the different phytosociological classes to the rice field weed flora is presented.

De los 49 táxones registrados (29 emergentes y 20 flotantes o sumergidos 11 son exóticos introducidos, de los cuales los más importantes son Echinochloa oryzoides y E. oryzicolaen ambas zonas, además de Cyperus difformis y Echinochloa hispidula en Valencia, y el resto propios de la flora autóctona, predominando Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli y Paspalum distichum como emergentes, Lemna minor y L. gibba como flotantes, Potamogeton nodosus, Zannichellia palustris y Najas minor como sumergidos y Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme. Spirogyra spp., Pirhophora oedogonia e Hydrodictyon reticulatum como algas macroscópicas. Se analiza la evolución experimentada por la flora en los últimos años, además de estudiar las

Duckweed cultures in animal wastewaters

Energy Technology Data Exchange (ETDEWEB)

Corradi, M; Copelli, M; Ghetti, P F

1981-01-01

Cultures of duckweed (Lemna gibba and L. minor) were made for 2 months in 2 ponds fed by a semicontinuous flow of partially treated animal wastewaters. The growth rate of the organic load were obtained from weekly data and the rate of removal of N and P was evaluated. At high loads (concentrations greater than 400 COD, 60 NH/sub 4/+, 10 mg/L PO/sub 4/ to the power of 3-) an average yield (dry weight) of approximately 7 g/square meters/day was established. The mean dry weight of biomass was 6%. The N and P content in duckweed was 1.1 and 4.7%, respective, and the daily absorption rates were 415 N and 97 mg/square meters/day P. The technique of skimming biomass at a rate proportional to the growth rate is useful to maintain duckweed cultures in continuous active growth conditions.

Stress and Protein Turnover in Lemna minor1

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Cooke, Robert J.; Oliver, Jane; Davies, David D.

1979-01-01

Transfer of fronds of Lemna minor L. to adverse growth conditions or stress situations causes a lowering of the growth rate and a loss of soluble protein per frond, the extent of the loss being dependent on the nature of the stress. The loss or protein is due to two factors: (a) a decrease in the rate constant of protein synthesis (ks); (b) an increase in the rate constant of protein degradation (kd). In plants adapted to the stresses, protein synthesis increases and the initially rapid rate of proteolysis is reduced. Addition of abscisic acid both lowers ks and increases kd, whereas benzyladenine seems to alleviate the effects of stress on protein content by decreasing kd rather than by altering ks. Based on the measurement of enzyme activities, stress-induced protein degradation appears to be a general phenomenon, affecting many soluble proteins. The adaptive significance of stress-induced proteolysis is discussed. PMID:16661102

The Phosphorylation of Ribosomal Protein in Lemna minor

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Trewavas, A.

1973-01-01

Sterile cultures of Lemna minor have been labeled with 32P1, and the ribosomal proteins have been examined for radioactivity. In relatively short term labeling a radioactive protein was found which ran as a single component in both urea/acetic acid and sodium lauryl sulfate gel electrophoresis. Acid hydrolysis of the labeled protein permitted the isolation of serine phosphate. After labeling to equilibrium with 32P1, calculation indicated only 0.6 to 0.75 atom of this protein phosphorus per ribosome. The phosphorylated protein is found in both polysomes and “derived” monomers and appears to be located in the ribosomal small subunit. Its apparent molecular weight is 42,000. Addition of growth-inhibiting concentrations of abscisic acid does not alter the apparent degree of labeling of this protein in 5 hours, but after 24 hours of treatment the total protein phosphorus was reduced from 0.75 atom of phosphorus per ribosome to 0.36 atom of phosphorus per ribosome. PMID:16658405

Can aquatic macrophytes be biofilters for gadolinium based contrasting agents?

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Braun, Mihály; Zavanyi, Györgyi; Laczovics, Attila; Berényi, Ervin; Szabó, Sándor

2018-05-15

The use of gadolinium-based contrasting agents (GBCA) is increasing because of the intensive usage of these agents in magnetic resonance imaging (MRI). Waste-water treatment does not reduce anthropogenic Gd-concentration significantly. Anomalous Gd-concentration in surface waters have been reported worldwide. However, removal of GBCA-s by aquatic macrophytes has still hardly been investigated. Four aquatic plant species (Lemna gibba, Ceratophyllum demersum, Elodea nuttallii, E. canadensis) were investigated as potential biological filters for removal of commonly used but structurally different GBCA-s (Omniscan, Dotarem) from water. These plant species are known to accumulate heavy metals and are used for removing pollutants in constructed wetlands. The Gd uptake and release of the plants was examined under laboratory conditions. Concentration-dependent infiltration of Gd into the body of the macrophytes was measured, however significant bioaccumulation was not observed. The tissue concentration of Gd reached its maximum value between day one and four in L. gibba and C. demersum, respectively, and its volume was significantly higher in C. demersum than in L. gibba. In C. demersum, the open-chain ligand Omniscan causes two-times higher tissue Gd concentration than the macrocyclic ligand Dotarem. Gadolinium was released from Gd-treated duckweeds into the water as they were grown further in Gd-free nutrient solution. Tissue Gd concentration dropped by 50% in duckweed treated by Omniscan and by Dotarem within 1.9 and 2.9 days respectively. None of the macrophytes had a significant impact on the Gd concentration of water in low and medium concentration levels (1-256 μg L -1 ). Biofiltration of GBCA-s by common macrophytes could not be detected in our experiments. Therefore it seems that in constructed wetlands, aquatic plants are not able to reduce the concentration of GBCA-s in the water. Furthermore there is a low risk that these plants cause the

ANALISIS PENGARUH VARIASI SUHU dan WAKTU PADA PROSES HIDROLISIS TERHADAP KADAR GLUKOSA DALAM PEMANFAATAN Lemna minor SEBAGAI BIOETANOL

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Vivi Mayangsari

2014-10-01

Full Text Available Energi terbarukan sangatlah diperlukan karena semakin meluasnya krisis energi sehingga memerlukan alternatif selain penggunaan bahan bakar fosil, penggunaan bioethanol merupakan alternatif yang baik karena banyak kelebihanya. Lemna minor merupakan salah satu tumbuhan yang berpotensi sebagai bioethanol, hal ini dapat dilihat dari kandungan glukosanya yang tinggi. Tujuan penelitian ini adalah untuk mengetahui hubungan waktu dan suhu pada proses hidrolisis terhadap nilai kadar glukosa serta mengetahui hubungan densitas terhadap kadar etanol. Proses ekstrasi glukosa menggunakan perbandingan volume HCl dengan kosentrasi 0,1 N, berat serbuk Lemna minor dan volume aquades yaitu 1:10:100 dengan variasi waktu ekstrasi 60, 90, dan 120 menit pada variasi suhu 60, 70, 80 °C dengan ukuran serbuk 60 mesh. Hasil penelitian ekstrasi hidrolisis terbaik pada menit ke-90 didapatkan panjang gelombang tertinggi 415 nm. Semua glukosa pada ekstrasi 90 menit difermentasi menggunakan bakteri Saccharomiches cerevisiae sebanyak 10% dari volume glukosa dengan waktu 144 jam, setelah fermentasi selesai sampel didestilasi untuk menghilangkan kadar air dan dihasilkan kadar ethanol terbaik 0,47% dengan densitas 0,9345 gr/ml3pada panjang gelombang larutan glukosa 316 nm.

The Application of Low-Cost Adsorbent for Reactive Blue 19 Dye Removal from Aqueous Solution: Lemna Minor

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Davoud Balarak

2015-10-01

Full Text Available Background & Aims of the Study: Due to widespread use and adverse effect of dyes, the removal of dyes from effluents is necessary. This study was aimed to remove the reactive blue 19 dye removal from aqueous solution by dried Lemna minor. Materials and Methods:  The effect of various parameters including contact time, solution pH, adsorbent dosage and dye concentration was investigated in this experimental-lab study, Also, the isotherm and kinetic studies was performed for RB19 dye adsorption process. Results: The results indicated that RB19 dye removal efficiency increases by increasing of contact time and adsorbent dosage. The equilibrium time was 75 min ad the maximum dye removal efficiency was obtained in pH=3. Also, the dye removal efficiency decreases by increasing of pH and initial concentration. It was found that the equilibrium data was best follow by Langmuier isotherm. Also, the pseudo-second-kinetic model was best applicable for RB 19 dye adsorption. Conclusion: It can be concluded that the dried Lemna minor can be considered as an effective adsorbent to remove the RB19 dye.

Insights into the structural and physicochemical properties of small granular starches from two hydrophyte duckweeds, Spirodela oligorrhiza and Lemna minor.

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Chen, Lei; Yu, Changjiang; Ma, Yubin; Xu, Hua; Wang, Shumin; Wang, Yu; Liu, Xingxun; Zhou, Gongke

2016-11-29

The structure and physicochemical properties of starches from two hydrophyte duckweeds, Spirodela oligorrhiza and Lemna minor, were investigated and compared in this study. The amylose content and average size of starches were determined to be 20.85%, 4.70 μm and 27.77%, 6.17 μm for Spirodela oligorrhiza and Lemna minor, respectively. The average chain length of two duckweed starches was measured to be around DP 28. The chain length distribution was observed to be greatly different from other reported starches for the high proportion of long chains (DP ≥ 37) over 50%. Wide-angle X-ray diffraction profiles of the two starch samples displayed typical B-type diffraction pattern. The gelatinization enthalpy-changes (ΔH gel ) of two starch samples was about 10.40 J/g for two duckweed starches. The present results suggested the potential utilization of small granular starches from duckweed in functional foods and dietary supplement products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Plant growth-promoting bacterium Acinetobacter calcoaceticus P23 increases the chlorophyll content of the monocot Lemna minor (duckweed) and the dicot Lactuca sativa (lettuce).

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Suzuki, Wakako; Sugawara, Masayuki; Miwa, Kyoko; Morikawa, Masaaki

2014-07-01

Acinetobacter calcoaceticus P23 is a plant growth-promoting bacterium that was isolated from the surface of duckweed (Lemna aoukikusa). The bacterium was observed to colonize on the plant surfaces and increase the chlorophyll content of not only the monocotyledon Lemna minor but also the dicotyledon Lactuca sativa in a hydroponic culture. This effect on the Lactuca sativa was significant in nutrient-poor (×1/100 dilution of H2 medium) and not nutrient-rich (×1 or ×1/10 dilutions of H2 medium) conditions. Strain P23 has the potential to play a part in the future development of fertilizers and energy-saving hydroponic agricultural technologies. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Boron accumulation by Lemna minor L. under salt stress.

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Liu, Chunguang; Gu, Wancong; Dai, Zheng; Li, Jia; Jiang, Hongru; Zhang, Qian

2018-06-12

Excess boron (B) is toxic to aquatic organisms and humans. Boron is often present in water with high salinity. To evaluate the potential of duckweed (Lemna minor L.) for removing B from water under salt stress, we cultured duckweed in water with 2 mg/L of B and sodium chloride (NaCl) concentrations ranging from 0 to 200 mM for 4 days. The results show that with increasing salinity, the capacity of L. minor to accumulate B initially decreased and then increased. L. minor used different mechanisms to accumulate boron at lower and higher levels of salt stress. The growth and chlorophyll synthesis of L. minor were significantly inhibited when the concentration of NaCl reached 100 mM. Our results suggest that L. minor is suitable for the accumulation of B when NaCl salinity is below 100 mM.

A simple method for analysing the effects of algae on the growth of Lemna and preventing algal growth in duckweed bioassays

NARCIS (Netherlands)

Szabo, S.; Roijackers, R.M.M.; Scheffer, M.

2003-01-01

A simple novel method for indoor culture experiments with small floating water plants, such as Lemnaceae, is described. Experiments demonstrate that the method allows for longer lasting culture experiments with Lemna, avoiding algal growth and self-shading of fronds by overcrowding. This is achieved

Efficacité des méthodes de lutte contre le développement de cinq espèces de plantes invasives amphibies : Crassula helmsii, Hydrocotyle ranunculoides, Ludwigia grandiflora, Ludwigia peploides et Myriophyllum aquaticum (synthèse bibliographique)

OpenAIRE

Delbart, E.; Mahy, G.; Monty, A.

2013-01-01

Effectiveness of techniques used to control the development of five invasive amphibious plant species: Crassula helmsii, Hydrocotyle ranunculoides, Ludwigia grandiflora, Ludwigia peploides and Myriophyllum aquaticum. A review. Among rapidly spreading invasive species in Europe, amphibious plants are particularly problematic. These plants are capable of developing a photosynthetic activity both below and above the water surface, and they typically form dense floating populations. Controlling a...

Isolation of Vibrio cholera El Tor Inaba From Lemna minor and Eichhornia crassipens Roots in Veracruz, Mexico

OpenAIRE

Cordoba Aguilar, Edgar; Herrera Rivero, Marisol; Rubi, Alberto; Arroyo-Helguera, Omar; Coutino Rodriguez, Rocio

2014-01-01

Background: During epidemic periods, the strain Vibrio cholera El Tor has been isolated from the aquatic macrophyte roots of Eichhornia crassipens and Lemna minor, suggesting that aquatic plants could be environmental reservoirs through either a non-specific association or a commensalism relationship. Therefore, it is important to understand V. cholera reservoirs in order to establish prevention strategies against this pathogen. Objectives: Our interest was to determine whether V. cholera cou...

Effects of gamma radiation in a wide range of doses on the morphological characteristics of Lemna minor L

International Nuclear Information System (INIS)

Rasskazova, M.M.; Berestina, A.V.

2011-01-01

The effects of gamma radiation on the morphological parameters of Lemna minor L. were studied. As the sensitive parameters were invited to use chlorosis and necrosis. Significant differences between samples begin to show after 14 days of observation. The presence of effect, irrespective of the dose in the range 0,1-30 Gy, shows the efficiency of a sufficiently small dose (0,1 Gy) was revealed.

Aquatic arsenic: phytoremediation using floating macrophytes.

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Rahman, M Azizur; Hasegawa, H

2011-04-01

Phytoremediation, a plant based green technology, has received increasing attention after the discovery of hyperaccumulating plants which are able to accumulate, translocate, and concentrate high amount of certain toxic elements in their above-ground/harvestable parts. Phytoremediation includes several processes namely, phytoextraction, phytodegradation, rhizofiltration, phytostabilization and phytovolatilization. Both terrestrial and aquatic plants have been tested to remediate contaminated soils and waters, respectively. A number of aquatic plant species have been investigated for the remediation of toxic contaminants such as As, Zn, Cd, Cu, Pb, Cr, Hg, etc. Arsenic, one of the deadly toxic elements, is widely distributed in the aquatic systems as a result of mineral dissolution from volcanic or sedimentary rocks as well as from the dilution of geothermal waters. In addition, the agricultural and industrial effluent discharges are also considered for arsenic contamination in natural waters. Some aquatic plants have been reported to accumulate high level of arsenic from contaminated water. Water hyacinth (Eichhornia crassipes), duckweeds (Lemna gibba, Lemna minor, Spirodela polyrhiza), water spinach (Ipomoea aquatica), water ferns (Azolla caroliniana, Azolla filiculoides, and Azolla pinnata), water cabbage (Pistia stratiotes), hydrilla (Hydrilla verticillata) and watercress (Lepidium sativum) have been studied to investigate their arsenic uptake ability and mechanisms, and to evaluate their potential in phytoremediation technology. It has been suggested that the aquatic macrophytes would be potential for arsenic phytoremediation, and this paper reviews up to date knowledge on arsenic phytoremediation by common aquatic macrophytes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Functional Response (FR) and Relative Growth Rate (RGR) Do Not Show the Known Invasiveness of Lemna minuta (Kunth)

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Boets, Pieter; Goethals, Peter L. M.

2016-01-01

Growing travel and trade threatens biodiversity as it increases the rate of biological invasions globally, either by accidental or intentional introduction. Therefore, avoiding these impacts by forecasting invasions and impeding further spread is of utmost importance. In this study, three forecasting approaches were tested and combined to predict the invasive behaviour of the alien macrophyte Lemna minuta in comparison with the native Lemna minor: the functional response (FR) and relative growth rate (RGR), supplemented with a combined biomass-based nutrient removal (BBNR). Based on the idea that widespread invasive species are more successful competitors than local, native species, a higher FR and RGR were expected for the invasive compared to the native species. Five different nutrient concentrations were tested, ranging from low (4 mgN.L-1 and 1 mgP.L-1) to high (70 mgN.L-1 and 21 mgP.L-1). After four days, a significant amount of nutrients was removed by both Lemna spp., though significant differences among L. minor and L. minuta were only observed at lower nutrient concentrations (lower than 17 mgN.L-1 and 6 mgP.L-1) with higher nutrient removal exerted by L. minor. The derived FR did not show a clear dominance of the invasive L. minuta, contradicting field observations. Similarly, the RGR ranged from 0.4 to 0.6 d-1, but did not show a biomass-based dominance of L. minuta (0.5 ± 0.1 d-1 versus 0.63 ± 0.09 d-1 for L. minor). BBNR showed similar results as the FR. Contrary to our expectations, all three approaches resulted in higher values for L. minor. Consequently, based on our results FR is sensitive to differences, though contradicted the expectations, while RGR and BBNR do not provide sufficient power to differentiate between a native and an invasive alien macrophyte and should be supplemented with additional ecosystem-based experiments to determine the invasion impact. PMID:27861603

Geomagnetic and strong static magnetic field effects on growth and chlorophyll a fluorescence in Lemna minor.

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Jan, Luka; Fefer, Dušan; Košmelj, Katarina; Gaberščik, Alenka; Jerman, Igor

2015-04-01

The geomagnetic field (GMF) varies over Earth's surface and changes over time, but it is generally not considered as a factor that could influence plant growth. The effects of reduced and enhanced GMFs and a strong static magnetic field on growth and chlorophyll a (Chl a) fluorescence of Lemna minor plants were investigated under controlled conditions. A standard 7 day test was conducted in extreme geomagnetic environments of 4 µT and 100 µT as well as in a strong static magnetic field environment of 150 mT. Specific growth rates as well as slow and fast Chl a fluorescence kinetics were measured after 7 days incubation. The results, compared to those of controls, showed that the reduced GMF significantly stimulated growth rate of the total frond area in the magnetically treated plants. However, the enhanced GMF pointed towards inhibition of growth rate in exposed plants in comparison to control, but the difference was not statistically significant. This trend was not observed in the case of treatments with strong static magnetic fields. Our measurements suggest that the efficiency of photosystem II is not affected by variations in GMF. In contrast, the strong static magnetic field seems to have the potential to increase initial Chl a fluorescence and energy dissipation in Lemna minor plants. © 2015 Wiley Periodicals, Inc.

GST(phi) gene from Macrophyte Lemna minor is involved in cadmium exposure responses

Institute of Scientific and Technical Information of China (English)

CHEN Shihua; CHEN Xin; DOU Weihong; WANG Liang; YIN Haibo; GUO Shanli

2016-01-01

Reactive oxygen species (ROS) scavengers,including ascorbate peroxidase,superoxide dismutase,catalase and peroxidase,are the most commonly used biomarkers in assessing an organisms' response to many biotic and abiotic stresses.In this study,we cloned an 866 bp GST(phi) gene in Lemna minor and investigated its characteristics,expression and enzymatic activities under 75 μmol/L cadmium concentrations in comparison with other ROS scavengers.GST(phi) gene expression patterns were similar to those of other scavengers of ROS.This suggests that GST(phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution.

GST ( phi) gene from Macrophyte Lemna minor is involved in cadmium exposure responses

Science.gov (United States)

Chen, Shihua; Chen, Xin; Dou, Weihong; Wang, Liang; Yin, Haibo; Guo, Shanli

2016-03-01

Reactive oxygen species (ROS) scavengers, including ascorbate peroxidase, superoxide dismutase, catalase and peroxidase, are the most commonly used biomarkers in assessing an organisms' response to many biotic and abiotic stresses. In this study, we cloned an 866 bp GST ( phi) gene in Lemna minor and investigated its characteristics, expression and enzymatic activities under 75 μmol/L cadmium concentrations in comparison with other ROS scavengers. GST ( phi) gene expression patterns were similar to those of other scavengers of ROS. This suggests that GST ( phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution.

Circadian Rhythmicity in the Activities of Phenylalanine Ammonia-Lyase from Lemna perpusilla and Spirodela polyrhiza 1

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Gordon, William R.; Koukkari, Willard L.

1978-01-01

The oscillations in phenylalanine ammonia-lyase activity from Spirodela polyrhiza and phenylalanine ammonia-lyase and tyrosine ammonia-lyase activities from Lemna perpusilla displayed a circadian rhythm under continuous light. Rhythmicity in enzymic activity could not be detected in continuous darkness since under this condition phenylalanine ammonia-lyase activity remains at a fairly constantly low level. Results from our studies of the oscillatory pattern of the respective activities of phenylalanine and tyrosine ammonia-lyase support their “inseparability.” PMID:16660569

Nanometer-scale elongation rate fluctuations in the Myriophyllum aquaticum (Parrot feather) stem were altered by radio-frequency electromagnetic radiation.

Science.gov (United States)

Senavirathna, Mudalige Don Hiranya Jayasanka; Asaeda, Takashi; Thilakarathne, Bodhipaksha Lalith Sanjaya; Kadono, Hirofumi

2014-01-01

The emission of radio-frequency electromagnetic radiation (EMR) by various wireless communication base stations has increased in recent years. While there is wide concern about the effects of EMR on humans and animals, the influence of EMR on plants is not well understood. In this study, we investigated the effect of EMR on the growth dynamics of Myriophyllum aquaticum (Parrot feather) by measuring the nanometric elongation rate fluctuation (NERF) using a statistical interferometry technique. Plants were exposed to 2 GHz EMR at a maximum of 1.42 Wm(-2) for 1 h. After continuous exposure to EMR, M. aquaticum plants exhibited a statistically significant 51 ± 16% reduction in NERF standard deviation. Temperature observations revealed that EMR exposure did not cause dielectric heating of the plants. Therefore, the reduced NERF was due to a non-thermal effect caused by EMR exposure. The alteration in NERF continued for at least 2.5 h after EMR exposure and no significant recovery was found in post-EMR NERF during the experimental period.

ANALISIS PENGARUH VARIASI PERSENTASE RAGI (Saccharomyces cerevisiae DAN WAKTU PADA PROSES FERMENTASI DALAM PEMANFAATAN DUCKWEED (Lemna minor SEBAGAI BIOETANOL

Directory of Open Access Journals (Sweden)

Siti Khodijah

2015-04-01

Full Text Available Salah satu alternatif dalam mendukung ketersediaan sumber daya energi terbarukan adalah dengan memanfaatkan sumber dari non fosil seperti bioetanol. Bioetanol merupakan etanol yang dibuat dari biomass yang mengandung komponen pati (karbohidrat atau selulosa yang selanjutnya di fermentasi menggunakan bantuan mikroorganisme (Sacharomyces cerevisiae. Karbohidrat yang digunakan pada penelitian ini berasal dari Lemna minor (Duckweed. Penelitian ini bertujuan membuat bioetanol dari Lemna minor dengan variasi penambahan ragi dan lamanya waktu fermentasi terhadap nilai kadar etanol dan nilai densitas, serta mengetahui hubungan densitas dengan kadar etanol. Produksi bioetanol dari tanaman yang mengandung pati (karbohidrat, dilakukan melalui proses konversi karbohidrat menjadi gula (glukosa dengan hidrolisis asam (HCl, hidrolisat yang diperoleh selanjutnya dilakukan fermentasi dengan menambahkan yeast atau ragi sehingga diperoleh bioetanol. Variabel yang digunakan adalah perubahan massa ragi 5%,15%, dan 25% serta lama fermentasi 5, 6, dan 7 hari . Hasil penelitian menunjukkan lama fermentasi dan persentase ragi mempengaruhi kadar etanol. Nilai kadar etanol optimum diperoleh presentase ragi 25% dengan lama fermentasi 7 hari sebesar 3.81% dengan density optimum sebesar 0.9438 gr/cm3, Hubungan nilai densitas berbanding terbalik dengan peningkatan kadar etanol.

Seasonality distribution of the abundance and activity of nitrification and denitrification microorganisms in sediments of surface flow constructed wetlands planted with Myriophyllum elatinoides during swine wastewater treatment.

Science.gov (United States)

Li, Xi; Zhang, Miaomiao; Liu, Feng; Chen, Liang; Li, Yuyuan; Li, Yong; Xiao, Rulin; Wu, Jinshui

2018-01-01

Surface flow constructed wetlands (SFCWs) planted with Myriophyllum elatinoides for treatment of swine wastewater were examined to evaluate the effect of season, segment (site S1, S2, and S3), and treatment (100mgL -1 TN, T1; 300mgL -1 TN, T2; 500mgL -1 TN, T3) on the activity, and abundances of nitrifying and, denitrifying microorganisms, and on the abundance of sediment bacteria. The activity and abundances of nitrifiers, denitrifiers, and the abundance of bacteria were the highest in T3 samples, especially in S1 (Pswine wastewater treatment stimulate the growth of nitrifiers, denitrifiers and bacteria in sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biting midges (Diptera: Ceratopogonidae from Martín García Island, Argentina

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María M Ronderos

2011-09-01

Full Text Available Nearly 230 species of biting midges have been recorded or described from Argentina; 38 of them are known from the Buenos Aires province and only one is cited from Martín García Island. This paper presents the results raised from six collecting trips which took place on the island during spring 2005, summer 2006 and autumn 2009. Diverse sampling sites including permanent and temporary aquatic environments were chosen, most of the ten sampling sites were ponds of diverse origin, some of these environments were covered with floating vegetation as Lemna gibba, Lemna minuscule, Salvinia biloba, Salvinia minima, Azolla filiculoides, Limnobium laevigatum, Pistia stratiotes, Spirodela intermedia, Wolffiella oblonga and Wolffia columbiana. Other sites were placed in urban and suburban areas. Adults were collected with sweep nets at sunrise and sunset and with light traps at intervals of four to five hours at night, depending on electricity availability on the island. Larvae and pupae were collected with different implements depending on characteristics of each surveyed aquatic habitat. In free standing water, they were captured with small sieves or hand pipettes and micropipettes, flotation techniques were utilized for sampling vegetated areas, free and rooted floating hydrophytes were extracted for removing insects among them. Thirteen species of Ceratopogonidae were collected, three of Atrichopogon Kieffer, three of Forcipomyia Meigen, two of Dasyhelea Kieffer, four of Culicoides Latreille, and one of Bezzia Kieffer, all representing new records from the island. Rev. Biol. Trop. 59 (3: 1183-1194. Epub 2011 September 01.Alrededor de 230 especies de ceratopogónidos han sido registradas o descritas en Argentina, 38 de ellas son conocidas para la provincia de Buenos Aires y sólo una ha sido previamente citada para la Isla Martín García. En este trabajo se presentan los resultados obtenidos a partir de muestreos realizados en seis viajes a la isla

Discrimination of Species and Hybrid Detection in Myriophyllum Spp.: an Introduction to Biodiversity Conservation and Invasion Avoidance

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R Ghahramanzadeh

2014-03-01

Full Text Available Minimizing economical loss through introduction of invasive alien species (IAS in local ecosystem is one of the most important issues in biosecurity. The hybridization potential between non-indigenous and native species has raised concerns due mainly to introgression, which can cause extirpation of native species through gene contamination. In the present study, 71 samples belonging to 12 species from Myriophyllum genus were assessed in Plant Breeding group of Wageningen University. Internal transcribed spacer (ITS was used for identification of invasive species from related native and possible hybrid plants. The result showed that based on universal application, high sequence divergence and species discrimination, ITS is a powerful sequence for the identification of invasive species from related non-invasive foreign and native species. In contrast to morphological data, ITS grouped suspected hybrid plants in to M. heterophyllum and demonstrated that they have not resulted from hybridization. These observations suggest that multiple introduction and genetic recombination among different introduced genotypes or genetic pools could be reasons of non-flowering in suspected hybrid plants. Results showed that molecular markers enable to distinguish invasive plant species from their most closely related congeners. This could be helpful with enforcing a ban on important of such invasive which can help to plant ecosystem and biodiversity stability.

Toxicity of the fluoroquinolone antibiotics enrofloxacin and ciprofloxacin to photoautotrophic aquatic organisms.

Science.gov (United States)

Ebert, Ina; Bachmann, Jean; Kühnen, Ute; Küster, Anette; Kussatz, Carola; Maletzki, Dirk; Schlüter, Christoph

2011-12-01

The present study investigated the growth inhibition effect of the fluoroquinolone antibiotics enrofloxacin and ciprofloxacin on four photoautotrophic aquatic species: the freshwater microalga Desmodesmus subspicatus, the cyanobacterium Anabaena flos-aquae, the monocotyledonous macrophyte Lemna minor, and the dicotyledonous macrophyte Myriophyllum spicatum. Both antibiotics, which act by inhibiting the bacterial DNA gyrase, demonstrated high toxicity to A. flos-aquae and L. minor and moderate to slight toxicity to D. subspicatus and M. spicatum. The cyanobacterium was the most sensitive species with median effective concentration (EC50) values of 173 and 10.2 µg/L for enrofloxacin and ciprofloxacin, respectively. Lemna minor proved to be similarly sensitive, with EC50 values of 107 and 62.5 µg/L for enrofloxacin and ciprofloxacin, respectively. While enrofloxacin was more toxic to green algae, ciprofloxacin was more toxic to cyanobacteria. Calculated EC50s for D. subspicatus were 5,568 µg/L and >8,042 µg/L for enrofloxacin and ciprofloxacin, respectively. These data, as well as effect data from the literature, were compared with predicted and reported environmental concentrations. For two of the four species, a risk was identified at ciprofloxacin concentrations found in surface waters, sewage treatment plant influents and effluents, as well as in hospital effluents. For ciprofloxacin the results of the present study indicate a risk even at the predicted environmental concentration. In contrast, for enrofloxacin no risk was identified at predicted and measured concentrations. Copyright © 2011 SETAC.

Phytoremediation Potential of Duckweed (Lemna minor L.) On Steel Wastewater.

Science.gov (United States)

Saha, Priyanka; Banerjee, Angela; Sarkar, Supriya

2015-01-01

An eco-friendly and cost effective technique- phytoremediation was used to remediate contaminants from waste water. This study demonstrated that phytoremediation ability of duckweed (Lemna minor L.) to remove chloride, sulphate from Biological Oxygen Treatment (BOT) waste water of coke oven plant. The BOT water quality was assessed by analyzing physico-biochemical characters--pH, Biological oxygen demand (BOD), Chemical oxygen demand (COD), total dissolved solids (TDS) and elemental concentration. It was observed that an increase in pH value indicated an improvement of water quality. The experimental results showed that, duckweed effectively removed 30% chloride, 16% sulphate and 14% TDS from BOT waste water, which suggested its ability in phytoremediation for removal of chloride and sulphate from BOT waste water. A maximum increase of 30% relative growth rate of duckweed was achieved after 21 days of experiment. Thus, it was concluded that duckweed, an aquatic plant, can be considered for treatment of the effluent discharged from the coke oven plant.

Tolerance of Myriophyllum aquaticum to exposure of industrial wastewater pretreatment with electrocoagulation and their efficiency in the removal of pollutants.

Science.gov (United States)

Cano-Rodríguez, Claudia Teodora; Roa-Morales, Gabriela; Amaya-Chávez, Araceli; Valdés-Arias, Ricardo Antonio; Barrera-Díaz, Carlos Eduardo; Balderas-Hernández, Patricia

2014-01-01

The wastewater used in this study was obtained from a treatment plant where it mixed with wastewater of 142 industries and was treated using electrocoagulation with iron electrode and phytoremediation with Myriophyllum aquaticum, likewise certain biomarkers of oxidative stress of the plant were evaluated to find out its resistance to contaminant exposure. Electrocoagulation was performed under optimum operating conditions at pH 8 and with a current density of 45.45 A m(-2) to reduce the COD by 42%, color 89% and turbidity 95%; the electrochemical method produces partial elimination of contaminants, though this was improved using phytoremediation. Thus the coupled treatment reduced the COD by 94%, color 97% and turbidity 98%. The exposure of M. aquaticum to electrocoagulated wastewater did not have an effect on the ratio of chlorophyll a/b (2.84 + 0.24); on the activity of SOD, CAT and lipoperoxidation. The results show the potential of M. aquaticum to remove contaminants from pretreated wastewater since the enzymatic system of the plants was not significantly affected.

Potential use of Lemna minor for the phytoremediation of isoproturon and glyphosate.

Science.gov (United States)

Dosnon-Olette, Rachel; Couderchet, Michel; Oturan, Mehmet A; Oturan, Nihal; Eullaffroy, Philippe

2011-07-01

Pesticides are being detected in water bodies on an increasingly frequent basis. The present study focused on toxicity and phytoremediation potential of aquatic plants to remove phytosanitary products from contaminated water. We investigated the capacity of Lemna minor (L. minor) to eliminate two herbicides isoproturon and glyphosate from their medium. Since phytoremediation relies on healthy plants, pesticide toxicity was evaluated by exposing plants to 5 concentrations (0-20 microg L(-1) for isoproturon and 0-120 microg L(-1) for glyphosate) in culture media for 4 d using growth rate and chlorophyll a fluorescence as endpoints. At exposure concentrations of 10 microg x L(-1) for isoproturon and 80 microg x L(-1) for glyphosate, effects on growth rate and chlorophyll fluorescence were minor (isoproturon and glyphosate, respectively.

Fate, toxicity and bioconcentration of cadmium on Pseudokirchneriella subcapitata and Lemna minor in mid-term single tests.

Science.gov (United States)

Clément, Bernard; Lamonica, Dominique

2018-03-01

In the frame of a project which consists in modeling a laboratory microcosm under cadmium pressure, we initiated this study on the fate and effects of cadmium in the presence of either the microalga Pseudokirchneriella subcapitata or the duckweed Lemna minor, two organisms of the microcosm. For each organism, growth inhibition tests on a duration of 2-3 weeks were carried out with the objective of linking effects with total dissolved, ionic and internalized forms of cadmium. Numbers of organisms (algal cells or duckweed fronds) in 2-L beakers filled with synthetic nutritive medium containing EDTA were counted during the course of assays, while cadmium concentrations in the water and in the organisms were measured. Free cadmium fraction was calculated using PHREEQC, a computer program for chemical speciation. Results showed that cadmium toxicity to microalgae could be correlated to the free divalent fraction of this metal, limited by the presence of EDTA, and to its concentration in the organisms. Bioconcentration factors for our medium were suggested for P. subcapitata (111,000 on the basis of free cadmium concentration) and L. minor (17,812 on the basis of total dissolved concentration). No effect concentrations were roughly estimated around 400 µg/g for Pseudokirchneriella subcapitata and 200-300 µg/g for Lemna minor. This study is a first step towards a fate model based on chemical speciation for a better understanding of microcosm results.

Disposable electrochemical sensor to evaluate the phytoremediation of the aquatic plant Lemna minor L. toward Pb(2+) and/or Cd(2+).

Science.gov (United States)

Neagu, Daniela; Arduini, Fabiana; Quintana, Josefina Calvo; Di Cori, Patrizia; Forni, Cinzia; Moscone, Danila

2014-07-01

In this work a miniaturized and disposable electrochemical sensor was developed to evaluate the cadmium and lead ion phytoremediation potential by the floating aquatic macrophyte Lemna minor L. The sensor is based on a screen-printed electrode modified "in-situ" with bismuth film, which is more environmentally friendly than the mercury-based sensor usually adopted for lead and cadmium ion detection. The sensor was coupled with a portable potentiostat for the simultaneous measurement of cadmium and lead ions by stripping analysis. The optimized analytical system allows the simultaneous detection of both heavy metals at the ppb level (LOD equal to 0.3 and 2 ppb for lead and cadmium ions, respectively) with the advantage of using a miniaturized and cost-effective system. The sensor was then applied for the evaluation of Pb(2+) or/and Cd(2+) uptake by measuring the amount of the heavy metals both in growth medium and in plant tissues during 1 week experiments. In this way, the use of Lemna minor coupled with a portable electrochemical sensor allows the set up of a model system able both to remove the heavy metals and to measure "in-situ" the magnitude of heavy metal removal.

Biodiesel production from Jatropha curcas L. oil using Lemna perpusilla Torrey ash as heterogeneous catalyst

International Nuclear Information System (INIS)

Chouhan, Ashish Pratap Singh; Sarma, Anil Kumar

2013-01-01

Refined Jatropha curcas L. oil (JCO) and methanol were used as the reactants for the transesterification reactions in a Radleys reactor in the presence of a heterogeneous ash catalyst derived from the waste aquatic plant Lemna perpusilla Torrey. Physical characterization of the catalyst showed partly crystalline behaviour and a moderate surface area 9.622 m 2 g −1 . The L. perpusilla Torrey ashes obtained from traditional combustion method were further calcined at 550 ± 5 °C before use. In addition to other non-metal and metallic constitutes the ash contains 11.3% potassium which attributed to its catalytic behaviour. The cumulative mass fraction of 89.43% of the oil was converted to biodiesel at 65 ± 5 °C in 5 h at 1:9 M ratio of oil to alcohol with 5% of the ash as catalyst. The biodiesel (FAME) so obtained were characterized using appropriate ASTM methods and found within the defined standard limits. The catalyst could be reused upto 3-times but there is a reduction of efficacy by about 25% for 3rd consecutive batch reaction. The activation energy was calculated for FAME and found to be 29.49 kJ mol −1 . -- Highlights: ► Lemna perpusilla Torrey ash is a potential heterogeneous catalyst. ► The catalyst has moderately good surface area and pores. ► The ash contain 11.3% potassium which is attributed to its catalytic behaviour. ► 89.43% of the refined Jatropha curcas oil could be converted to FAME in a Radleys reactor. ► The activation energy for FAME was calculated and found to be 29.49 kJ mol −1

Biting midges (Diptera: Ceratopogonidae from Martín García Island, Argentina

Directory of Open Access Journals (Sweden)

María M Ronderos

2011-09-01

Full Text Available Nearly 230 species of biting midges have been recorded or described from Argentina; 38 of them are known from the Buenos Aires province and only one is cited from Martín García Island. This paper presents the results raised from six collecting trips which took place on the island during spring 2005, summer 2006 and autumn 2009. Diverse sampling sites including permanent and temporary aquatic environments were chosen, most of the ten sampling sites were ponds of diverse origin, some of these environments were covered with floating vegetation as Lemna gibba, Lemna minuscule, Salvinia biloba, Salvinia minima, Azolla filiculoides, Limnobium laevigatum, Pistia stratiotes, Spirodela intermedia, Wolffiella oblonga and Wolffia columbiana. Other sites were placed in urban and suburban areas. Adults were collected with sweep nets at sunrise and sunset and with light traps at intervals of four to five hours at night, depending on electricity availability on the island. Larvae and pupae were collected with different implements depending on characteristics of each surveyed aquatic habitat. In free standing water, they were captured with small sieves or hand pipettes and micropipettes, flotation techniques were utilized for sampling vegetated areas, free and rooted floating hydrophytes were extracted for removing insects among them. Thirteen species of Ceratopogonidae were collected, three of Atrichopogon Kieffer, three of Forcipomyia Meigen, two of Dasyhelea Kieffer, four of Culicoides Latreille, and one of Bezzia Kieffer, all representing new records from the island. Rev. Biol. Trop. 59 (3: 1183-1194. Epub 2011 September 01.

Ecotoxicological assessment of the herbicide Winner Top and its active substances-are the other formulants truly inert?

Science.gov (United States)

Queirós, Libânia; Vidal, Tânia; Nogueira, António J A; Gonçalves, Fernando J M; Pereira, Joana Luísa

2018-05-03

Formulants used in Plant Protection Products (PPPs) to promote their efficiency are normally undisclosed in the PPP documentation, unless they bear a human health or environmental hazardous potential per se. PPP regulation also demands the assessment of putative interactions among formulants within each product recipe and consequent effects, but these results are often unavailable. Such a case is that of the herbicide Winner Top (Selectis®, Portugal), which we selected as a model commercial formulation in the present study specifically aiming at (i) characterising its aquatic toxicity towards sensitive eco-receptors (Raphidocelis subcapitata, Chlorella vulgaris, Lemna minor and Lemna gibba), as well as that of its active substances (a.s.) nicosulfuron and terbuthylazine; (ii) comparing the ecotoxicity among the commercial formulation, the corresponding mixture of its a.s. and this a.s.'s mixture increasingly enriched with the formulants. Single chemical testing revealed that terbuthylazine was the strongest microalgae growth inhibitor and nicosulfuron was the strongest macrophyte growth inhibitor. On the other hand, the commercial formulation was consistently less toxic than the corresponding mixture of the a.s., suggesting that Winner Top formulants (72.9% of the commercial formulation) interact with the a.s., promoting less than additive effects in the selected non-target species. Importantly, this environmentally protective effect of the formulation can be apparent. Because macrophytes share most physiological features with the weeds targeted by the studied herbicide, it is likely that increased application doses are required to reach desired efficacy levels with the consequent detrimental increase of PPP residues load in edge-of-field freshwater ecosystems.

Pós-tratamento de efluente de reator anaeróbio em lagoa com lemna

OpenAIRE

Lubarino, Elizângela Alves

2013-01-01

A ausência de tratamento e a disposição inadequada de efluentes domésticos contribuem para a deterioração de corpos receptores. Porém, dentre as alternativas propostas para o pós-tratamento de águas residuárias estão as lagoas de lemnas. Essas lagoas são capazes de captar nutrientes do esgoto com eficiência, bem como, reduzir uma grande quantidade de sólidos em suspensão. Também atuam na inibição de algas, e geram biomassa rica em proteínas que tem utilidades como ração animal e adubo. Esta p...

Avaliação de lagoas de lemnas para o polimento de esgoto doméstico

OpenAIRE

Tonon, Gustavo

2016-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Ambiental, Florianópolis, 2016. As lagoas de lemnas têm sido utilizadas com sucesso para o polimento de efluentes nos últimos anos, destacando a grande capacidade de remoção de nutrientes, e a produção de biomassa passível de valorização. O presente estudo objetivou avaliar esta tecnologia no tratamento de esgoto doméstico, investigar a produção de gás metano em test...

Injury of Hg2+ and DBS on Lemna minor%Hg2+、DBS对浮萍的伤害研究

Institute of Scientific and Technical Information of China (English)

马剑敏; 王琳; 杜晋立; 吴晶敏

2001-01-01

The injury degree of Lemna minor by the stress of Hg2+ and DBSare reported.The concentrations of chlorophyll and dissolved protein decrease with the increase of Hg2+ and DBS concentrations or as treatment time is continued,dead percentage increase with the increase of Hg2+ and DBS concentrations or as treatment time is continued.When the concentrations of HgCl2 is 6mg/L or DBS is 12mg/L,about 70% of Lemna minor can live for 10 days at least.%研究了在Hg2+、DBS胁迫下，浮萍(LemnaminorL.)植株的枯死率、叶绿素含量和可溶性蛋白质含量的变化。植株的枯死率随Hg2+、DBS浓度升高和处理时间的延长而增加；叶绿素和蛋白质含量随Hg2+和DBS浓度升高和处理时间的延长而逐渐下降。在HgCl2、DBS浓度分别为6mg/L、12mg/L时，约70%的浮萍10d内仍存活。

Effects of fluorescent lighting on in vitro micropropagation of Lemna minor

Science.gov (United States)

Somsri, Kollawat; Pinyopich, Pataradawn; Mohammed, Waleed S.

2010-05-01

The vegetative in vitro propagation of Lemna minor stain SING-4 exposed to two different types of fluorescent light sources, Philips TLD 36W/54 and Toshiba FL40T8BRF/36, was studied. The liquid culture medium contained 4.43gl-1 phytohormone-free full-strength Murashige & Skoog (MS) basal medium with vitamins, 30gl-1 sucrose, and 1gl-1 MES. The results showed that both plant cultures had undergone normal asexual reproduction with an exponential increase trend. Cultures exposed to Toshiba FL40T8BRF/36 reproduced at a slightly faster rate while expressing significantly greener foliage (leaf color chart shade No.8), which indicates the presence of more chlorophyll, than cultures exposed to Philips TLD 36W/54 (leaf color chart shade No.4). The data obtained from our experiment reveals that light emitted from Toshiba FL40T8BRF/36 produces healthier and higher quality cultures.

cpDNA microsatellite markers for Lemna minor (Araceae): Phylogeographic implications.

Science.gov (United States)

Wani, Gowher A; Shah, Manzoor A; Reshi, Zafar A; Atangana, Alain R; Khasa, Damase P

2014-07-01

A lack of genetic markers impedes our understanding of the population biology of Lemna minor. Thus, the development of appropriate genetic markers for L. minor promises to be highly useful for population genetic studies and for addressing other life history questions regarding the species. • For the first time, we characterized nine polymorphic and 24 monomorphic chloroplast microsatellite markers in L. minor using DNA samples of 26 individuals sampled from five populations in Kashmir and of 17 individuals from three populations in Quebec. Initially, we designed 33 primer pairs, which were tested on genomic DNA from natural populations. Nine loci provided markers with two alleles. Based on genotyping of the chloroplast DNA fragments from 43 sampled individuals, we identified one haplotype in Quebec and 11 haplotypes in Kashmir, of which one occurs in 56% of the genotypes, one in 8%, and nine in 4%, respectively. There was a maximum of two alleles per locus. • These new chloroplast microsatellite markers for L. minor and haplotype distribution patterns indicate a complex phylogeographic history that merits further investigation.

The Applicability of Lemna aequinoctialis to Growth Inhibition Test of Lemna minor%青萍生长抑制试验对稀脉浮萍的适用性研究

Institute of Scientific and Technical Information of China (English)

梁艺怀; 张琨; 张京佶; 刘敏; 赵华清; 殷浩文

2015-01-01

为了验证我国本土常见的稀脉浮萍(Lemna aequinoctialis)是否适用于以青萍(Lemna minor)作为标准试验生物的生长抑制试验,对两种浮萍的毒性效应终点和毒性响应差异进行比较.通过对两种浮萍的总叶面积、干重、鲜重同叶状体数之间的相关性进行分析,根据《OECD化学品测试准则No.221浮萍生长抑制试验》,遵从良好实验室规范(GLP),将两种浮萍暴露于参比物质3,5-二氯苯酚,进行7d更新式毒性试验,暴露浓度为(1.0 ～ 10) mg·L-1.结果表明,青萍的培养条件、试验方法以及毒性效应终点均适用于稀脉浮萍,两种浮萍的毒性试验呈现出相似的时间-效应关系和剂量-效应关系,两者的毒性效应浓度具有可比性,且数值上接近.以上实验结果可以得出,稀脉浮萍适用于生长抑制试验;鉴于稀脉浮萍在我国分布广泛、容易获取,稀脉浮萍可作为毒性测试的国家标准试验生物.

The first draft genome of the aquatic model plant Lemna minor opens the route for future stress physiology research and biotechnological applications

OpenAIRE

Van Hoeck, Arne; Horemans, Nele; Monsieurs, Pieter; Cao, Hieu Xuan; Vandenhove, Hildegarde; Blust, Ronny

2015-01-01

Background: Freshwater duckweed, comprising the smallest, fastest growing and simplest macrophytes has various applications in agriculture, phytoremediation and energy production. Lemna minor, the so-called common duckweed, is a model system of these aquatic plants for ecotoxicological bioassays, genetic transformation tools and industrial applications. Given the ecotoxic relevance and high potential for biomass production, whole-genome information of this cosmopolitan duckweed is needed. Res...

Micro-scale elemental partition in tissues of the aquatic plant Lemna minor L. exposed to highway drainage water

International Nuclear Information System (INIS)

Mendes Godinho, R.; Raimundo, J.; Vale, C.; Anes, B.; Brito, P.; Alves, L.C.; Pinheiro, T.

2013-01-01

In the scope of a monitoring program to assess the environmental impact of automobile traffic over one main bridge in Lisbon, both water and duckweed (Lemna minor L.) were sampled from the road drainage tanks and analyzed for chemical elements. Plants uptake Cr, Mn, Cu, and Zn metals from rain water draining the bridge road. Nuclear microprobe elemental maps of cryosections of L. minor tissues showed that incorporated elements were internalized in fronds of the plant. This approach at micrometer level allows a better knowledge of the elemental tissue partitioning in this biomonitor organism

Micro-scale elemental partition in tissues of the aquatic plant Lemna minor L. exposed to highway drainage water

Science.gov (United States)

Mendes Godinho, R.; Raimundo, J.; Vale, C.; Anes, B.; Brito, P.; Alves, L. C.; Pinheiro, T.

2013-07-01

In the scope of a monitoring program to assess the environmental impact of automobile traffic over one main bridge in Lisbon, both water and duckweed (Lemna minor L.) were sampled from the road drainage tanks and analyzed for chemical elements. Plants uptake Cr, Mn, Cu, and Zn metals from rain water draining the bridge road. Nuclear microprobe elemental maps of cryosections of L. minor tissues showed that incorporated elements were internalized in fronds of the plant. This approach at micrometer level allows a better knowledge of the elemental tissue partitioning in this biomonitor organism.

Ecological life histories of the three aquatic nuisance plants, Myriophyllum spicatum, Potamogeton crispus and Elodea canadensis

Science.gov (United States)

Nichols, S.A.; Shaw, B.H.

1986-01-01

The life histories of Myriophyllum spicatum L., Elodea canadensis Michx., and Potamogeton crispus L., serious aquatic nuisances in many regions of the world, are reviewed to provide insights into the life style of successful aquatic nuisance plants. Specifically, their distribution and spread in North America; their life cycle, productive and reproductive potential; and their ecosystem relationships are reviewed. Hopefully this review will improve a manager's ability to deal with aquatic nuisance problems. It also provides suggestions for basic research needed to develop more effective management practices. It was found that all three species possess a number of adaptations, including an ability to rapidly propagate vegetatively, an opportunistic nature for obtaining nutrients, a life cycle that favors cool weather, and a number of mechanisms which enhance photosynthetic efficiency, which allow them to proliferate. These three species do provide benefits to the ecosystem through their roles in materials cycling and energy flow. Therefore, management of these species should take an integrated approach which recognizes these benefits. The life history information available about the three species varies tremendously; however, a better understanding of resource gain and allocation is needed to manage all three species. Specifically, more research is needed to provide a better understanding of: 1) the role bicarbonate plays in photosynthesis, 2) the role roots play in supplying CO2 to the plabts, 3) resource accumulation and allocation under different temperature and light regimes, 4) resource allocation on a seasonal basis, and 5) nutrient cycling under different management regimes. ?? 1986 Dr W. Junk Publishers.

Efeito do cobre na atividade da enzima pirogalol peroxidase em plantas de Myriophyllum aquaticum cultivadas em solução nutritiva Effect of copper on the activity of pirogalol peroxidase in Myriophyllum aquaticum plants cultivated in nutritives solution

Directory of Open Access Journals (Sweden)

V.D. Domingos

2005-06-01

Full Text Available Myriophyllum aquaticum é uma planta perene, herbácea, que pode se desenvolver totalmente submersa ou com a porção terminal dos ramos acima da superfície da água. É também considerada uma planta daninha que possui elevado potencial de colonização, o qual, dependendo da densidade populacional, pode causar aumento no teor de matéria orgânica e redução de oxigênio na água, comprometendo a qualidade da água e seus usos múltiplos. O objetivo do presente trabalho foi verificar a influência do cobre na atividade da pirogalol peroxidase de plantas de M. aquaticum submetidas à solução nutritiva contendo concentrações de cobre de 1,2; 11,2; 21,2; 31,2; e 41,2 µg L-1. O experimento foi conduzido em um delineamento experimental inteiramente casualizado, com quatro repetições e cinco tratamentos, aos quais as plantas foram submetidas durante 21 dias. Aos 81 dias após a instalação das mudas em solução nutritiva contendo os diferentes níveis de cobre, as folhas foram colhidas a partir do ápice da planta até o final do ramo, que não estavam em contato com a solução. Esse material fresco foi envolvido por plástico transparente e papel-alumínio e, a seguir, congelado em nitrogênio líquido, sendo armazenado em freezer a -20 ºC até o momento da determinação da atividade da enzima pirogalol peroxidase. A atividade da enzima foi progressiva com o aumento das doses de cobre. As plantas cultivadas com 40 µg L-1 de Cu2+ após três semanas, com base em avaliação visual, apresentaram redução no desenvolvimento.Myriophyllum aquaticum is a perennial, herbaceous plant which grows totally submerged or with the terminal portion of the branches above the surface of the water. It is also considered to be a harmful plant, possessing a high colonization potential which, depending on population density, can increase the organic matter content and reduce oxygen in the water, compromising the quality of water and its multiple uses

青萍在Pb、Cu污染水体植物修复中的应用研究%Study of duckweed（Lemna perpusilla Torr.） for use in phytoremediation of lead-and copper-contaminated water bodies

Institute of Scientific and Technical Information of China (English)

唐艳葵; 韦星任; 姚秋艳; 蓝梓铭; 李婷

2011-01-01

Duckweed（Lemna perpusilla Torr.） was used as experimental materials and several physiological responses of Lemna perpusilla Torr.,such as biomass growth,pigment contents,adsorption characteristics of heavy metals,nitrogen and phosphorus,to elevated concentrations of Pb（Ⅱ）（up to 40 mg/L） and Cu（Ⅱ）（up to 4 mg/L） were investigated.The results showed that high metal concentration might inhibit the growth of Lemna perpusilla Torr.Copper was found to be more toxic to plants than lead.It was demonstrated that exposure to high concentrations of lead and copper results in the high bioaccumulation of metals in Lemna perpusilla Torr.（26.09 mg/g of Pb in the plant grown in water with 40 mg/L Pb（Ⅱ） and 2.49 mg/g of Cu in the plant grown in water with 4 mg/L Cu（Ⅱ））.At these levels the plant growth was significantly inhibited and the plant pigment content significantly decreased.Also,a significant release of P and N was observed at these high levels of metal stress.The results of this study confirm that Lemna perpusilla Torr.is a suitable candidate for the phytoremediation in low-level lead-contaminated water bodies.%以青萍种浮萍（Lemna perpusilla Torr.）为实验材料,以Pb（Ⅱ）、Cu（Ⅱ）为染毒因子,设定金属离子浓度梯度（Pb（Ⅱ）：0～40 mg/L,Cu（Ⅱ）：0～4 mg/L）,考察了在不同金属离子浓度下青萍生长状况、叶片色素含量以及金属离子浓度对青萍N、P和金属离子吸收能力的影响。结果表明：金属离子浓度的越高,青萍生长受抑制越严重;Cu（Ⅱ）对青萍的毒害大于Pb（Ⅱ）;在Pb（Ⅱ）浓度为40 mg/L,Cu（Ⅱ）浓度为4 mg/L时,青萍对Pb（Ⅱ）和Cu（Ⅱ）的平均单位鲜重富集量分别为26.09 mg/g和2.49 mg/g,但同时,青萍的生长受到严重抑制,叶绿素含量急剧下降,且N、P从细胞中溶出。研究表明,青萍比较适宜修复被低浓度Pb（Ⅱ）污染的水体。

cpDNA Microsatellite Markers for Lemna minor (Araceae: Phylogeographic Implications

Directory of Open Access Journals (Sweden)

Gowher A. Wani

2014-07-01

Full Text Available Premise of the study: A lack of genetic markers impedes our understanding of the population biology of Lemna minor. Thus, the development of appropriate genetic markers for L. minor promises to be highly useful for population genetic studies and for addressing other life history questions regarding the species. Methods and Results: For the first time, we characterized nine polymorphic and 24 monomorphic chloroplast microsatellite markers in L. minor using DNA samples of 26 individuals sampled from five populations in Kashmir and of 17 individuals from three populations in Quebec. Initially, we designed 33 primer pairs, which were tested on genomic DNA from natural populations. Nine loci provided markers with two alleles. Based on genotyping of the chloroplast DNA fragments from 43 sampled individuals, we identified one haplotype in Quebec and 11 haplotypes in Kashmir, of which one occurs in 56% of the genotypes, one in 8%, and nine in 4%, respectively. There was a maximum of two alleles per locus. Conclusions: These new chloroplast microsatellite markers for L. minor and haplotype distribution patterns indicate a complex phylogeographic history that merits further investigation.

Application of in-situ bioassays with macrophytes in aquatic mesocosm studies.

Science.gov (United States)

Coors, Anja; Kuckelkorn, Jochen; Hammers-Wirtz, Monika; Strauss, Tido

2006-10-01

Aquatic mesocosm studies assess ecotoxicological effects of chemicals by using small artificial ponds as models of lentic ecosystems. In this study, methods of controlled insertion of macrophytes within an outdoor mesocosm study were explored. Although analytically confirmed concentrations of the model herbicide terbuthylazine were high enough to expect direct effects on phytoplankton, functional parameters and dominant taxa abundance indicated only minor and transient effects. In-situ assays with Lemna minor, Myriophyllum spicatum, Potamogeton lucens and Chara globularis revealed adverse effects at concentrations in accordance with literature data. Complex interactions such as nutrient limitation and competition were possible reasons for the observed growth promotion at the lower concentration of about 5 microg/l terbuthylazine. The approach of macrophyte in-situ bioassays within a mesocosm study proved to be applicable. Presumed advantages are simultaneous acquisition of toxicity data for several species of aquatic plants under more realistic conditions compared to laboratory tests and inclusion of macrophytes as important structural and functional components in mesocosms while limiting their domination of the model ecosystem.

Micropropagation of Myriophyllum alterniflorum (Haloragaceae) for stream rehabilitation: first in vitro culture and reintroduction assays of a heavy-metal hyperaccumulator immersed macrophyte.

Science.gov (United States)

Delmail, David; Labrousse, Pascal; Hourdin, Philippe; Larcher, Laure; Moesch, Christian; Botineau, Michel

2013-01-01

Nowadays, submersed aquatic macrophytes play a key role in stream ecology and they are often used as biomonitors of freshwater quality. So, these plants appear as natural candidates to stream rehabilitation experiments. Among them, the stream macrophyte Myriophyllum alterniflorum is used recently as biomonitor and is potentially useful for the restoration of heavy-metal contaminated localities. The best way to obtain a mass production of watermilfoil plants is micropropagation. We developed in vitro culture of M. alterniflorum and the effects of five media on the plant development were assessed. Five morphological and four physiological endpoints were examined leading to the recommendation of the Murashige and Skoog medium for ecotoxicological studies on chlorophyllous parts, and of the Gaudet medium for root cytotoxicity and phytoremediation studies. Micropropagated clones were acclimatized in a synthetic medium and in situ reintroduction was performed efficiently. This is the first report of micropropagated plants transplantation in streams. The successful establishment of watermilfoil beds even in polluted areas strongly suggested that ecological restoration using micropropagated watermilfoil is a promising biotechnology for phytoremediation and rehabilitation of degraded areas. Moreover, high bioconcentration factors evidenced that watermilfoil hyperaccumulates Cd and Cu, and could be potentially used in phytoremediation studies.

Temperature-dependent toxicity of artemisinin toward the macrophyte Lemna minor and the algae Pseudokirchneriella subcapitata

DEFF Research Database (Denmark)

Jessing, Karina Knudsmark; Andresen, Marianne; Cedergreen, Nina

2014-01-01

- and groundwater. To make better risk assessments of A. annua which is cultivated under varying climatic conditions, the temperature-dependent toxicity of artemisinin toward the green algae Pseudokirchneriella subcapitata and the macrophyte Lemna minor was evaluated at temperatures ranging from 10 to 30°C....... To include a possible effect of temperature on the degradation rate of artemisinin, artemisinin concentrations were measured during the experiment and toxicity was related to the time-weighted averages of exposure concentrations. The toxicity of artemisinin toward the macrophyte L. minor and the algae P....... subcapitata increased with increasing growth rates, and we conclude that bioavailability plays a minor role in the observed relation between temperature and toxicity of artemisinin. The obtained results are important for possible future risk assessment of A. annua cultivation....

Capacidad de las macrofitas Lemna minor y Eichhornia crassipes para eliminar el niquel

Directory of Open Access Journals (Sweden)

BRES, P

2012-04-01

Full Text Available El objetivo de este trabajo fue estudiar la capacidad de dos especies de macrofitas, Lemna minor y Eichhornia crassipes, para eliminar el níquel. Se realizaron cuatro tratamientos durante dos semanas para cada una de las especies. Las plantas fueron incubadas con 0, 1, 3 y 6 mg l-1 de Ni. Ambas especies mostraron, en todos los tratamientos con Ni, una reducción en la concentración a lo largo del tiempo. L. minor mostró ser más eficiente para remover este ión a la más baja concentración. Sin embargo, en concentraciones más elevadas no se observaron diferencias entre ambas especies. El análisis del tejido de las plantas mostró que las mismas acumulaban el metal, en los tres casos evaluados con concentraciones diferentes.Palabras clave: fitorremediación, metales pesados, plantas acuáticas, acumulación.

水杨酸诱导膨胀浮萍（Lemna gibba SH0204）开花

Institute of Scientific and Technical Information of China (English)

黄猛; 许亚良; KanjanaKhaeso; 孙雪飘; 张家明

2015-01-01

用水杨酸（SA）诱导膨胀浮萍开花，结果显示，在液体1/2Hoagland培养基中加入适当浓度的SA对开花有显著促进作用， SA浓度为20μmol·L-1时开花率最高，达到39.37%。SA在诱导开花的同时，明显抑制叶状体的生长，在浓度为80μmol·L-1时，叶状体死亡率达到94.38%。此外，本研究尝试在固体1/2Hoagland培养基上诱导膨胀浮萍开花，结果表明，固体培养基比液体培养基更有利于诱导开花， SA浓度为20μmol·L-1时，开花率超过45%，死亡率显著降低。在固体培养基上，方便对开花植株进行跟踪和操作，因此，用固体培养基诱导开花比液体培养基更有应用价值。光学和电子显微镜的观察结果显示，花粉粒呈近圆球形，表面有网状带刺纹饰。

Bioremediation of an iron-rich mine effluent by Lemna minor.

Science.gov (United States)

Teixeira, S; Vieira, M N; Espinha Marques, J; Pereira, R

2014-01-01

Contamination of water resources by mine effluents is a serious environmental problem. In a old coal mine, in the north of Portugal (São Pedro da Cova, Gondoma),forty years after the activity has ended, a neutral mine drainage, rich in iron (FE) it stills being produced and it is continuously released in local streams (Ribeiro de Murta e Rio Ferreira) and in surrounding lands. The species Lemna minor has been shown to be a good model for ecotoxicological studies and it also has the capacity to bioaccumulate metals. The work aimed test the potential of the species L. minor to remediate this mine effluent, through the bioaccumulation of Fe, under greenhouse experiments and, at the same time, evaluate the time required to the maximum removal of Fe. The results have shown that L. minor was able to grow and develop in the Fe-rich effluent and bioaccumulating this element. Throughout the 21 days of testing it was found that there was a meaningful increase in the biomass of L. minor both in the contaminated and in the non-contaminated waters. It was also found that bioaccumulation of Fe (iron) occurred mainly during the first 7 days of testing. It was found that L. minor has potential for the bioremediation of effluents rich in iron.

cpDNA microsatellite markers for Lemna minor (Araceae): Phylogeographic implications1

Science.gov (United States)

Wani, Gowher A.; Shah, Manzoor A.; Reshi, Zafar A.; Atangana, Alain R.; Khasa, Damase P.

2014-01-01

• Premise of the study: A lack of genetic markers impedes our understanding of the population biology of Lemna minor. Thus, the development of appropriate genetic markers for L. minor promises to be highly useful for population genetic studies and for addressing other life history questions regarding the species. • Methods and Results: For the first time, we characterized nine polymorphic and 24 monomorphic chloroplast microsatellite markers in L. minor using DNA samples of 26 individuals sampled from five populations in Kashmir and of 17 individuals from three populations in Quebec. Initially, we designed 33 primer pairs, which were tested on genomic DNA from natural populations. Nine loci provided markers with two alleles. Based on genotyping of the chloroplast DNA fragments from 43 sampled individuals, we identified one haplotype in Quebec and 11 haplotypes in Kashmir, of which one occurs in 56% of the genotypes, one in 8%, and nine in 4%, respectively. There was a maximum of two alleles per locus. • Conclusions: These new chloroplast microsatellite markers for L. minor and haplotype distribution patterns indicate a complex phylogeographic history that merits further investigation. PMID:25202636

Phenol toxicity to the aquatic macrophyte Lemna paucicostata

Energy Technology Data Exchange (ETDEWEB)

Park, Ji-Sook [Division of Life Science, University of Incheon, Incheon 406-840 (Korea, Republic of); Brown, Murray T. [School of Marine Science and Engineering, University of Plymouth, Plymouth, Devon PL4 8AA (United Kingdom); Han, Taejun, E-mail: hanalgae@hanmail.net [Division of Life Science, University of Incheon, Incheon 406-840 (Korea, Republic of); Institute of Green Environmental Research, University of Incheon, Incheon 406-840 (Korea, Republic of)

2012-01-15

Phenol is a ubiquitous environmental pollutant and a widely used reference toxicant for many bioassays. However, little information is available regarding the toxic effects of phenol on aquatic macrophytes. Seventy-two hour bioassays, with different end-points, were carried out to assess phenol toxicity in Lemna paucicostata. A concentration-dependent decline in frond multiplication and colony disintegration was observed, with 11.38 and 22.76 {mu}M phenol resulting in browning of fronds and colony disintegration, respectively. Growth of fronds, as measured by changes in surface area, was significantly inhibited with EC{sub 50} value of 2.70 {mu}M. When pulse amplitude modulated chlorophyll a (Chl a) fluorescence imaging (i-PAM) was employed, the maximum quantum yield of PS II (F{sub v}/F{sub m}) significantly declined with increasing phenol concentrations with resultant EC{sub 50} of 1.91 {mu}M and coefficients of variation (CVs) generated for the EC{sub 50} values of less than 4.7%. A gradual increase in fluorescence emissions from chlorophylls a and b and pheophytin up to a concentration of 2.85 {mu}M was found but declined markedly at higher concentrations. The significant correlation between the F{sub v}/F{sub m} and surface growth rate data implies that the former is an appropriate biomarker of whole plant toxicity. Using imaging Chl a fluorescence on L. paucicostata provides a rapid, sensitive and reliable method for assessing the toxic risks posed by phenol to aquatic ecosystems and has practical applications for municipal and industrial waste water management.

Phenol toxicity to the aquatic macrophyte Lemna paucicostata

International Nuclear Information System (INIS)

Park, Ji-Sook; Brown, Murray T.; Han, Taejun

2012-01-01

Phenol is a ubiquitous environmental pollutant and a widely used reference toxicant for many bioassays. However, little information is available regarding the toxic effects of phenol on aquatic macrophytes. Seventy-two hour bioassays, with different end-points, were carried out to assess phenol toxicity in Lemna paucicostata. A concentration-dependent decline in frond multiplication and colony disintegration was observed, with 11.38 and 22.76 μM phenol resulting in browning of fronds and colony disintegration, respectively. Growth of fronds, as measured by changes in surface area, was significantly inhibited with EC 50 value of 2.70 μM. When pulse amplitude modulated chlorophyll a (Chl a) fluorescence imaging (i-PAM) was employed, the maximum quantum yield of PS II (F v /F m ) significantly declined with increasing phenol concentrations with resultant EC 50 of 1.91 μM and coefficients of variation (CVs) generated for the EC 50 values of less than 4.7%. A gradual increase in fluorescence emissions from chlorophylls a and b and pheophytin up to a concentration of 2.85 μM was found but declined markedly at higher concentrations. The significant correlation between the F v /F m and surface growth rate data implies that the former is an appropriate biomarker of whole plant toxicity. Using imaging Chl a fluorescence on L. paucicostata provides a rapid, sensitive and reliable method for assessing the toxic risks posed by phenol to aquatic ecosystems and has practical applications for municipal and industrial waste water management.

A marriage of convenience; a simple food chain comprised of Lemna minor (L.) and Gammarus pulex (L.) to study the dietary transfer of zinc.

Science.gov (United States)

Lahive, E; O'Halloran, J; Jansen, M A K

2015-01-01

Macrophytes contribute significantly to the cycling of metals in aquatic systems, through accumulation during growth and release during herbivory or decomposition. Accumulation of high levels of metals has been extensively documented in Lemnaceae (duckweeds). However, the degree of trophic transfer of metals from Lemnaceae to secondary consumers remains poorly understood. This study demonstrates that zinc accumulated in Lemna minor is bioavailable to the herbivore consumer Gammarus pulex. Overall, the higher the zinc content of L. minor, the more zinc accumulated in G. pulex. Accumulation in G. pulex was such that mortality occurred when they were fed high zinc-containing L. minor. Yet, the percentage of consumed zinc retained by G. pulex actually decreased with higher zinc concentrations in L. minor. We hypothesise that this decrease reflects internal zinc metabolism, including a shift from soluble to covalently bound zinc in high zinc-containing L. minor. Consistently, relatively more zinc is lost through depuration when G. pulex is fed L. minor with high zinc content. The developed Lemna-Gammarus system is simple, easily manipulated, and sensitive enough for changes in plant zinc metabolism to be reflected in metal accumulation by the herbivore, and therefore suitable to study ecologically relevant metal cycling in aquatic ecosystems. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Effect of pH, temperature, and lead concentration on the bioremoval of lead from water using Lemna minor.

Science.gov (United States)

Uysal, Yağmur; Taner, Fadime

2009-09-01

This study examined the ability of the aquatic plant Lemna minor (duckweed) to remove soluble lead under various laboratory conditions. In a batch process L. minor was exposed to different pH values (4.5-8.0) and temperature (15-35 degrees C) in presence of different lead concentrations (0.1-10.0 mg L(-1)) for 168 h. The amount of biomass obtained in the study period on a dry weight basis, the concentrations of lead in tissue and in medium and net uptake of lead by Lemna all have been determined in each condition. The percentages of lead uptake ratios (PMU) and bioconcentration factors (BCF) were also calculated for these conditions. Bioaccumulated lead concentrations and the PMU were obtained at lowest pH of 4.5, and at 30 degrees C. The highest accumulated lead concentration was found at pH 4.5 as 3.599 mg Pb g(-1) in 10.0 mg L(-1). It decreased to pH 6.0, but it did not change at pH 6.0-8.0 range. The maximum lead accumulation was obtained at 30 degrees C as 8.622 mg Pb g(-1) in 10 mg L(-1) at pH 5.0, and the minimum was at 15 degrees C as 0.291 mg g(-1) in 0.1 mg L(-1). Lead accumulation gradually increased with increasing lead in medium, but the opposite trend was observed for PMU. Lead accumulation increased up to 50 mg L(-1), but did not change significantly in the 50.0-100.0 mg L(-1) range. The lead uptake from water was modeled and the equation fit the experimental data very well

Comparison of different physiological parameter responses in Lemna minor and Scenedesmus obliquus exposed to herbicide flumioxazin

International Nuclear Information System (INIS)

Geoffroy, Laure; Frankart, Cecile; Eullaffroy, Philippe

2004-01-01

The sensitivity of different physiological parameters in Scenedesmus obliquus and Lemna minor exposed to herbicide (flumioxazin) was investigated to indicate the most convenient and sensitive parameter. To assess toxicity of flumioxazin, we used a panel of biomarkers: pigment contents, chlorophyll fluorescence parameters and antioxidative enzyme activities. Algae and duckweed were exposed to 48-h IC 50 for growth rate. In L. minor, the sensitivity of the parameters was as follows: Q N >Oxygen emission>PHIs PSII >Q P >PHI PSII >CAT, GR>Pigment>APO>Growth. For S. obliquus, this ranking was as follows: CAT>Oxygen emission>Q P >APO>GR>Pigment>PHIs PSII >Growth>PHI PSII >Q N (from the greatest to the least sensitive). The results demonstrated that the observed toxicity is related not only to interspecific variations but also to the selected parameter

The Screening of Culture Method for Lemna%浮萍培养方法的筛选

Institute of Scientific and Technical Information of China (English)

孙源; 曹凯文; 王仁君; 丁宁; 曹泰; 张萍; 李青竹; 赵熙宇; 崔萍; 李亚琪; 赵翔宇

2017-01-01

Under laboratory conditions,duckweed as the research obj ect,we tested 3 common ways to culture Lemna-6-well plates,culture dishes and glass beakers.With laboratory experiments of batch cul-ture,the growth curves of Lemna were gotten and fitted by Logistic model.Specifically we examinated bio-mass、the content of protein、the content of chlorophyll and Fv/Fm .This results showed that:(1 )The growth curve has characteristic of sigmoidal shape and the growth rate has density-dependent characteris-tic.The value of r and k of Lemna in glass beakers is above 6-well plates and culture dishes.(2)In culture dishes of duckweed Fv/Fm is greater than glass beakers is greater than 6-well plates.(3)In glass beakers of duckweed chlorophyll is greater than 6-well plates is greater than culture dishes .(4)In glass beakers of duckweed protein is greater than 6-well plates is greater than culture dishes .So the beaker cultivation method of duckweed works best under laboratory conditions.It suggests that how to culture duckweed un-der laboratory.%在实验室条件下，以青萍为研究对象，比较了3种较为常见的室内浮萍培养方法———六孔板培养法，培养皿培养法，烧杯培养法。该研究采用序批式培养方式培养青萍，利用单种种群增长的 Logistic 模型对生物量的增长曲线进行了分析，同时测定了青萍的生物量、蛋白质含量、叶绿素含量、PSII 最大光化学效率(Fv/Fm )等生理指标。结果表明：(1)青萍的生物量随时间变化的增长曲线呈典型的“S”型，在特定的环境和营养条件下，单位面积上青萍生物量的增长受密度的制约。其中，烧杯培养的青萍的 r值和K值>六孔板>培养皿。(2)烧杯培养的青萍的Fv/Fm 值>六孔板>培养皿。(3)烧杯培养的青萍叶绿素含量>六孔板>培养皿。(4)�

Effect of Used Battery Lixivium on Growth of Lemna minor%废电池浸出液对青萍(Lemna minor)生长的影响

Institute of Scientific and Technical Information of China (English)

宋关玲; 马汇泉; 宋新华

2009-01-01

为了研究青萍(Lemna minor)是否可以应用于有废电池污染的富营养化地表水体的治理和生态修复中,用不同倍数稀释的废电池浸出液处理3d的青萍作为试验材料,研究了在短期培养条件下,废电池浸出液对青萍生长的影响,并测定了抗氧化系统的几种酶(POD、CAT、SOD)的活性以及可溶性蛋白质量分数的变化.研究表明:青萍对废电池浸出液很敏感,低质量浓度的废电池浸出液可以使青萍中活性氧的含量增高,高质量浓度的废电池浸出液可以使青萍抗氧化酶系统紊乱,该植物在有废电池污染的水体中应该慎重应用.

Compostaje de residuos orgánicos y de lenteja de agua (Lemna SP.) con aplicación microorganismos eficaces

OpenAIRE

Suaña Quispe, María Elena

2013-01-01

El estudio se realizó en el Departamento de Puno, Perú; en las instalaciones del laboratorio de Biología de la Facultad de Ciencias Biológicas durante los meses de Octubre a Diciembre del 2012, con el fin de elaborar compost a partir de residuos orgánicos domésticos y Lenteja de agua (Lemna spp.) aplicando microorganismos eficaces (EM) a tres dosis (0, 100 y 200 mi) se evaluó el tiempo de descomposición y granulometría, temperatura, pH, nitrógeno, fósforo, potasio y sodio. Se utilizó el análi...

Onderzoek naar een geschikte combinatie toetsmethoden ter bepaling van de aquatische toxiciteit van milieugevaarlijke stoffen. Bijl.2: Onderzoek naar de bruikbaarheid van Lemna minor (eendekroos) voor routine toxiciteitsonderzoek en vergelijking van deze waterplant met eencellige groenalgen

NARCIS (Netherlands)

Adema DMM; de Zwart D

1984-01-01

Als aanvulling op het project "Onderzoek naar een geschikte combinatie toetsmethoden ter bepaling van de aquatische toxiciteit van milieugevaarlijke stoffen" werd vergelijkend onderzoek verricht naar de bruikbaarheid en gevoeligheid van eendekroos (Lemna minor) als toetsorganisme. Deze

Correlations in metal release profiles following sorption by Lemna minor.

Science.gov (United States)

Üçüncü Tunca, Esra; Ölmez, Tolga T; Özkan, Alper D; Altındağ, Ahmet; Tunca, Evren; Tekinay, Turgay

2016-08-02

Following the rapid uptake of contaminants in the first few hours of exposure, plants typically attempt to cope with the toxic burden by releasing part of the sorbed material back into the environment. The present study investigates the general trends in the release profiles of different metal(loid)s in the aquatic macrophyte Lemna minor and details the correlations that exist between the release of metal(loid) species. Water samples with distinct contamination profiles were taken from Nilüfer River (Bursa, Turkey), Yeniçağa Lake (Bolu, Turkey), and Beyşehir Lake (Konya, Turkey) and used for release studies; 36 samples were tested in total. Accumulation and release profiles were monitored over five days for 11 metals and a metalloid ((208)Pb, (111)Cd, (52)Cr,(53)Cr,(60)Ni,(63)Cu,(65)Cu,(75)As,(55)Mn, (137)Ba, (27)Al, (57)Fe, (66)Zn,(68)Zn) and correlation, cluster and principal component analyses were employed to determine the factors that affect the release of these elements. Release profiles of the tested metal(loid)s were largely observed to be distinct; however, strong correlations have been observed between certain metal pairs (Cr/Ni, Cr/Cu, Zn/Ni) and principal component analysis was able to separate the metal(loid)s into three well-resolved groups based on their release.

Impact of polyethylene microbeads on the floating freshwater plant duckweed Lemna minor.

Science.gov (United States)

Kalčíková, Gabriela; Žgajnar Gotvajn, Andreja; Kladnik, Aleš; Jemec, Anita

2017-11-01

Microplastics (MP), small plastic particles below 5 mm, have become one of the central concerns of environmental risk assessment. Microplastics are continuously being released into the aquatic environment either directly through consumer products or indirectly through fragmentation of larger plastic materials. The aim of our study was to investigate the effect of polyethylene microbeads from cosmetic products on duckweed (Lemna minor), a freshwater floating plant. The effects of microbeads from two exfoliating products on the specific leaf growth rate, the chlorophyll a and b content in the leaves, root number, root length and root cell viability were assessed. At the same time, water leachates from microbeads were also prepared to exclude the contribution of cosmetic ingredients on the measured impacts. Specific leaf growth rate and content of photosynthetic pigments in duckweed leaves were not affected by polyethylene microbeads, but these microbeads significantly affected the root growth by mechanical blocking. Sharp particles also reduced the viability of root cells, while the impact of microbeads with a smooth surface was neglected. It was concluded that microbeads from cosmetic products can also have negative impacts on floating plants in freshwater ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Suitability of duckweed (Lemna minor as feed for fish in polyculture system

Directory of Open Access Journals (Sweden)

M.Z.H. Talukdar

2012-06-01

Full Text Available In the present study, we conducted an experiment to evaluate the effects of duckweed (Lemna minor as feed on fish production in polyculture. The experiment had 2 treatments where in treatment 1 (T1 ponds were supplied with duckweed as feed and in treatment 2 (T2 ponds were kept as control (without supply of duckweed. Average survival rates in T1 and T2 were 90 and 89%, respectively. The specific growth rates (SGR were higher in T1. Calculated net production in T1 was 6.25 tons ha.-1 yr.-1 and in T2 was 2.84 tons ha.-1 yr.-1. The ranges of physico-chemical parameters analyzed were within the productive limit and more or less similar in all the ponds under both treatments during the experimental period. There were 24 genera of phytoplankton under 5 major groups and 10 genera of zooplankton under 3 major groups found in the experimental ponds. The net production in T1 was significantly higher than that of T2 indicated the use of duckweed as feed for fishes is economically sustainable in polyculture.

Genetic programming-based mathematical modeling of influence of weather parameters in BOD5 removal by Lemna minor.

Science.gov (United States)

Chandrasekaran, Sivapragasam; Sankararajan, Vanitha; Neelakandhan, Nampoothiri; Ram Kumar, Mahalakshmi

2017-11-04

This study, through extensive experiments and mathematical modeling, reveals that other than retention time and wastewater temperature (T w ), atmospheric parameters also play important role in the effective functioning of aquatic macrophyte-based treatment system. Duckweed species Lemna minor is considered in this study. It is observed that the combined effect of atmospheric temperature (T atm ), wind speed (U w ), and relative humidity (RH) can be reflected through one parameter, namely the "apparent temperature" (T a ). A total of eight different models are considered based on the combination of input parameters and the best mathematical model is arrived at which is validated through a new experimental set-up outside the modeling period. The validation results are highly encouraging. Genetic programming (GP)-based models are found to reveal deeper understandings of the wetland process.

Toxic Effects of KBr on Lemna Minor%KBr对青萍的毒性效应

Institute of Scientific and Technical Information of China (English)

张萍; 李青竹; 李亚琪; 赵熙宇; 崔萍; 王仁君

2017-01-01

在实验室条件下,为了解溴化钾(KBr)对高等水生植物的毒性效应,以青萍(Lemna minorL.)为研究对象,采用连续式培养法进行培养,从生长、光合和抗氧化方面系统研究了不同浓度的KBr对青萍的毒性效应.实验结果表明:在0-20 μg/L溴化钾的处理下,与对照组相比,青萍的生长和生理生化指标并没有显著变化(P＞0.05),这说明KBr对青萍几乎没有毒害作用.上述实验结果为研究KBr对水生高等植物的毒性效应提供了理论支撑.

The Response of Lemna minor to Mixtures of Pesticides That Are Commonly Used in Thailand.

Science.gov (United States)

Tagun, Rungnapa; Boxall, Alistair B A

2018-04-01

In the field, aquatic organisms are exposed to multiple contaminants rather than to single compounds. It is therefore important to understand the toxic interactions of co-occurring substances in the environment. The aim of the study was to assess the effects of individual herbicides (atrazine, 2,4-D, alachlor and paraquat) that are commonly used in Thailand and their mixtures on Lemna minor. Plants were exposed to individual and binary mixtures for 7 days and the effects on plant growth rate were assesed based on frond area measurements. Experimental observations of mixture toxicity were compared with predictions based on single herbicide exposure data using concentration addition and independent action models. The single compound studies showed that paraquat and alachlor were most toxic to L. minor, followed by atrazine and then 2,4-D. For the mixtures, atrazine with 2,4-D appeared to act antagonistically, whereas alachlor and paraquat showed synergism.

Comparison of different physiological parameter responses in Lemna minor and Scenedesmus obliquus exposed to herbicide flumioxazin

Energy Technology Data Exchange (ETDEWEB)

Geoffroy, Laure; Frankart, Cecile; Eullaffroy, Philippe

2004-09-01

The sensitivity of different physiological parameters in Scenedesmus obliquus and Lemna minor exposed to herbicide (flumioxazin) was investigated to indicate the most convenient and sensitive parameter. To assess toxicity of flumioxazin, we used a panel of biomarkers: pigment contents, chlorophyll fluorescence parameters and antioxidative enzyme activities. Algae and duckweed were exposed to 48-h IC{sub 50} for growth rate. In L. minor, the sensitivity of the parameters was as follows: Q{sub N}>Oxygen emission>PHIs{sub PSII}>Q{sub P}>PHI{sub PSII}>CAT, GR>Pigment>APO>Growth. For S. obliquus, this ranking was as follows: CAT>Oxygen emission>Q{sub P}>APO>GR>Pigment>PHIs{sub PSII}>Growth>PHI{sub PSII}>Q{sub N} (from the greatest to the least sensitive). The results demonstrated that the observed toxicity is related not only to interspecific variations but also to the selected parameter.

Diferenciación molecular de Lemna aequinoctialis y L. Valdiviana (lemnaceae por patrones proteicos

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Mª del Milagro Montero Rojas

2016-03-01

Full Text Available El estudio se llevó a cabo en el Laboratorio de Genética Molecular de la Universidad Nacional, Heredia, Costa Rica. Se utilizaron plantas acuáticas macrófitas de Lemna valdiviana y L. aequinoctialis previamente identificadas. Estas especies habitan en aguas ricas en sales disueltas y aguas servidas. Recientemente se les consideró como un indicador de la contaminación ocasionada por pesticidas y herbicidas en el agua. La composición proteica llega a niveles entre 38 y 43% de materia seca, importante para diversos usos. La extracción de proteínas totales, por medio de electroforesis discontinua en gel de poliacrilamida, se realizó en condiciones reductoras con SDS (SDS-PAGE. Los geles separadores empleados fueron al 8 y 10%, gel espaciador al 4% y la tinción se efectuó con azul commassie. Los diversos patrones proteicos reflejaron diferencias genéticas entre ambas especies que se pueden deber a las diferencias de hábitat y de reproducción.

Catalytic production of levulinic acid and ethyl levulinate from uniconazole-induced duckweed (Lemna minor).

Science.gov (United States)

Liu, Chunguang; Feng, Qingna; Yang, Jirui; Qi, Xinhua

2018-05-01

Duckweed (Lemna minor) with a high starch content of 50.4% was cultivated by uniconazole-induction method. The cultivated duckweed was used to produce value-added chemicals such as glucose, levulinic acid and formic acid in diluted HCl aqueous solution. A high glucose yield of 93.4% (471 g/kg based on loading duckweed mass) could be achieved at 180 °C in short reaction time, and the generated glucose was converted into levulinic acid and formic acid with yields of 52.0% and 34.1%, respectively, for 150 min, corresponding to 262 g/kg levulinic acid yield and 171 g/kg formic acid yield based on the mass of loading duckweed, respectively. Moreover, the duckweed was efficiently converted to ethyl levulinate with 55.2% yield (400.6 g/kg) at 200 °C in ethanol. This work provides a promising strategy for the production of value-added chemicals from phytoplankton that is able to purify the wastewater containing high content of P and N. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preliminary assessment of heavy metals in water, sediment and macrophyte ( Lemna minor) collected from Anchar Lake, Kashmir, India

Science.gov (United States)

Showqi, Irfana; Lone, Farooq Ahmad; Naikoo, Mehrajuddin

2018-06-01

Water samples, sediments and free floating macrophytic plant, Lemna minor specimens were collected from five designated sites in Anchar lake (Srinagar, J&K, India) to assess its heavy metal (Cu, Cr, Zn, Ni, Cd, Pb) load and changes on seasonal basis. The concentration of heavy metals was determined using atomic absorption spectroscopy. Most of the samples were found within limits of maximum permissible concentrations as recommended by WHO (Guidelines for drinking water quality, pp 491-493, 2006). During all the seasons, highest concentration of all heavy metals (Cu, Cr, Zn, Ni, Cd, Pb) was recorded at highly polluted sites of the lake viz. near agricultural fields (S1), near settlements (S3) and SKIMS (S4). These sites received huge agrochemical run-off from the surrounding agricultural fields, solid and liquid wastes from the nearby catchment areas and effluents from Sher-e-Kashmir Institute of Medical Sciences (SKIMS) compared to control site lake centre (S5). Furthermore, most of the metals in water and sediment were found with highest concentration during autumn (Viz., Cu-1.5 ppm; Zn-0.38 ppm; Ni-1.89 ppm; Pb-0.84 ppm in water and Cu-26.9 ppm; Zn-13.6 ppm; Pb-4.33 ppm in sediment) and summer (Viz., Cr-0.68 ppm in water and Ni-4.8 ppm; Cd-2.6 ppm; Cr-8.01 ppm in sediment) seasons. Also in Lemna minor plant highest concentration was observed during summer season (Cu-29.09 ppm; Zn-19.11 ppm; Ni-5.7 ppm; Cd-1.34 ppm; Cr-9.18 ppm and Pb-9.77 ppm). From these observations, it was found that the sources of heavy metals in Anchar lake were both natural and anthropogenic ones. This study recommended that continuous monitoring of heavy metals (Viz; Cu, Cr, Zn, Ni, Cd and Pb) in water, sediment and other aquatic biota of Anchar lake should be directed to protection of ecological status of the lake and its surrounding area.

Studies on the Growth Effects of the Canaline-Urea Cycle Amino Acids with Lemna minor L. 1

Science.gov (United States)

Rosenthal, Gerald A.; Gulati, Dushyant K.; Sabharwal, P. S.

1975-01-01

The aquatic microphyte, Lemna minor L., was utilized to assess the relative toxicity and general growth effects of canavanine, canaline, ureidohomoserine (UHS), and canavaninosuccinate (CSA). These amino acids are constituents of the canaline-urea cycle and structural analogues of the ornithine-urea cycle amino acids. Comparative growth studies with L. minor revealed that the canaline-urea cycle amino acids are potent antimetabolites. With the exception of CSA, they are extremely toxic at a concentration of 5 μm. Over a concentration range of 1 to 4 μm, canavanine is the most growth-inhibiting of the canaline-urea cycle amino acids. At or above 5 μm, canavanine and canaline possess comparable toxicity. UHS is less growth-inhibiting than canavanine or canaline, and CSA is the least toxic of the canaline-urea cycle intermediates. PMID:16659316

Regulatory structure of the biosynthetic pathway for the aspartate family of amino acids in Lemna paucicostata Hegelm. 6746, with special reference to the role of aspartokinase

International Nuclear Information System (INIS)

Giovanelli, J.; Mudd, S.H.; Datko, A.H.

1989-01-01

Comprehensive studies were made with Lemna paucicostate Hegelm. 6746 of the effects of combinations of lysine, methionine, and threonine on growth rates, soluble amino acid contents, aspartokinase activities, and fluxes of 4-carbon moieties from aspartate through the aspartokinase step into the amino acids of the aspartate family. These studies show that flux in vitro through the aspartokinase step is insensitive to inhibition by lysine or threonine, and confirm previous in vitro data in establishing that aspartokinase in vivo is present in two orders of magnitude excess of its requirements. No evidence of channeling of the products of the lysine- and threonine-sensitive aspartokinases was obtained, either form of the enzyme along being more than adequate for the combined in vivo flux through the aspartokinase step. The marked insensitivity of flux through the aspartokinase step to inhibition by lysine or threonine strongly suggests that inhibition of aspartokinase by these amino acids is not normally a major factor in regulation of entry of 4-carbon units into the aspartate family of amino acids. Direct measurement of fluxes of 4-carbon units demonstrated that: (a) Lysine strongly feedback regulates its own synthesis, probably at the step catalyzed by dihydrodipicolinate synthase. (b) Threonine alone does not regulate its own synthesis in vivo, thereby confirming previous studies of the metabolism of [ 14 C]threonine and [ 14 C]homoserine in Lemna

Oxidative stress in duckweed (Lemna minor L.) caused by short-term cadmium exposure

Energy Technology Data Exchange (ETDEWEB)

Razinger, Jaka [Department for Environmental Technologies and Biomonitoring, Institute of Physical Biology, Veliko Mlacevo 59, SI-1290 Grosuplje (Slovenia)], E-mail: jaka@ifb.si; Dermastia, Marina [National Institute of Biology, Vecna pot 111, p.p. 141, SI-1001 Ljubljana (Slovenia); Biotechnical Faculty, Department of Biology, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Koce, Jasna Dolenc [Biotechnical Faculty, Department of Biology, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana (Slovenia); Zrimec, Alexis [Department for Environmental Technologies and Biomonitoring, Institute of Physical Biology, Veliko Mlacevo 59, SI-1290 Grosuplje (Slovenia)

2008-06-15

The mechanisms of plant defence against cadmium toxicity have been studied by short-term exposure of Lemna minor L. (common duckweed) to concentrations of CdCl{sub 2} ranging from 0 to 500 {mu}M. High accumulation of cadmium was observed (12,320 {+-} 2155 {mu}g g{sup -1} at 500 {mu}M CdCl{sub 2}), which caused a gradual decrease of plant growth, increased lipid peroxidation, and weakened the entire antioxidative defence. Total glutathione concentration decreased significantly; however, the concentration of oxidized glutathione remained stable. The responses of four antioxidant enzymes showed that catalase was the most inhibited after CdCl{sub 2} exposure, ascorbate peroxidase and guaiacol peroxidase moderately, and glutathione reductase least. The total antioxidative potential revealed an induced antioxidative network at 0.1 {mu}M CdCl{sub 2} (137 {+-} 13.2% of the control) and its reduction to only 47.4 {+-} 4.0% of the control at higher cadmium concentrations. The possible application of the examined biomarkers in ecotoxicological research is discussed. - The increase of total antioxidative potential at low cadmium concentration is one of the mechanisms that helps duckweed to cope with cadmium-induced oxidative stress.

Oxidative stress in duckweed (Lemna minor L.) caused by short-term cadmium exposure

International Nuclear Information System (INIS)

Razinger, Jaka; Dermastia, Marina; Koce, Jasna Dolenc; Zrimec, Alexis

2008-01-01

The mechanisms of plant defence against cadmium toxicity have been studied by short-term exposure of Lemna minor L. (common duckweed) to concentrations of CdCl 2 ranging from 0 to 500 μM. High accumulation of cadmium was observed (12,320 ± 2155 μg g -1 at 500 μM CdCl 2 ), which caused a gradual decrease of plant growth, increased lipid peroxidation, and weakened the entire antioxidative defence. Total glutathione concentration decreased significantly; however, the concentration of oxidized glutathione remained stable. The responses of four antioxidant enzymes showed that catalase was the most inhibited after CdCl 2 exposure, ascorbate peroxidase and guaiacol peroxidase moderately, and glutathione reductase least. The total antioxidative potential revealed an induced antioxidative network at 0.1 μM CdCl 2 (137 ± 13.2% of the control) and its reduction to only 47.4 ± 4.0% of the control at higher cadmium concentrations. The possible application of the examined biomarkers in ecotoxicological research is discussed. - The increase of total antioxidative potential at low cadmium concentration is one of the mechanisms that helps duckweed to cope with cadmium-induced oxidative stress

Lead toxicity to Lemna minor predicted using a metal speciation chemistry approach.

Science.gov (United States)

Antunes, Paula M C; Kreager, Nancy J

2014-10-01

In the present study, predictive measures for Pb toxicity and Lemna minor were developed from bioassays with 7 surface waters having varied chemistries (0.5-12.5 mg/L dissolved organic carbon, pH of 5.4-8.3, and water hardness of 8-266 mg/L CaCO3 ). As expected based on water quality, 10%, 20%, and 50% inhibitory concentration (IC10, IC20, and IC50, respectively) values expressed as percent net root elongation (%NRE) varied widely (e.g., IC20s ranging from 306 nM to >6920 nM total dissolved Pb), with unbounded values limited by Pb solubility. In considering chemical speciation, %NRE variability was better explained when both Pb hydroxides and the free lead ion were defined as bioavailable (i.e., f{OH} ) and colloidal Fe(III)(OH)3 precipitates were permitted to form and sorb metals (using FeOx as the binding phase). Although cause and effect could not be established because of covariance with alkalinity (p = 0.08), water hardness correlated strongly (r(2)  = 0.998, p minor and highlight the importance of chemical speciation in Pb-based risk assessments for aquatic macrophytes. © 2014 SETAC.

Potential of duckweed (Lemna minor) for removal of nitrogen and phosphorus from water under salt stress.

Science.gov (United States)

Liu, Chunguang; Dai, Zheng; Sun, Hongwen

2017-02-01

Duckweed plays a major role in the removal of nitrogen (N) and phosphorus (P) from water. To determine the effect of salt stress on the removal of N and P by duckweed, we cultured Lemna minor, a common species of duckweed, in N and P-rich water with NaCl concentrations ranging from 0 to 100 mM for 24 h and 72 h, respectively. The results show that the removal capacity of duckweed for N and P was reduced by salt stress. Higher salt stress with longer cultivation period exerts more injury to duckweed and greater inhibition of N and P removal. Severe salt stress (100 mM NaCl) induced duckweed to release N and P and even resulted in negative removal efficiencies. The results indicate that L. minor should be used to remove N and P from water with salinities below 75 mM NaCl, or equivalent salt stress. Copyright © 2016 Elsevier Ltd. All rights reserved.

Efficacité des méthodes de lutte contre le développement de cinq espèces de plantes invasives amphibies : Crassula helmsii, Hydrocotyle ranunculoides, Ludwigia grandiflora, Ludwigia peploides et Myriophyllum aquaticum (synthèse bibliographique

Directory of Open Access Journals (Sweden)

Delbart, E.

2013-01-01

Full Text Available Effectiveness of techniques used to control the development of five invasive amphibious plant species: Crassula helmsii, Hydrocotyle ranunculoides, Ludwigia grandiflora, Ludwigia peploides and Myriophyllum aquaticum. A review. Among rapidly spreading invasive species in Europe, amphibious plants are particularly problematic. These plants are capable of developing a photosynthetic activity both below and above the water surface, and they typically form dense floating populations. Controlling amphibious plants, whether for the purposes of total eradication or for the regulation of their spread, represents an important challenge for managers. A literature review of existing control methods for Crassula helmsii, Hydrocotyle ranunculoides, Ludwigia grandiflora, Ludwigia peploides and Myriophyllum aquaticu was carried out, taking into account efficiency and costs. Of the 87 studies analyzed, a great variation was evident in the research efforts undertaken (number and spatial scale of studies between species and between control methods. However, overall, the different control methods described showed a similar level of efficiency between species. Reports of total eradication of amphibious plants were rare. Such cases resulted from the application of mechanical or chemical methods, most often coupled with complementary methods such as manual finishing. The use of chemical control methods (less laborious and costly than others was found to be frequently documented in the literature. However, except in the case of some active substances, such chemical methods were found to provide low control efficiency. Similarly, to date, biological control has not been found to provide convincing results. In addition, it should be noted that several biological control agents are considered as invasive species in Europe. On the other hand, although little related research has been carried out, methods such as manual or mechanical removal with manual finishing have often

纳米ZnO对浮萍(Lemna minor L.)的生态毒性及其聚集性和溶解性分析%Ecotoxicity of ZnO Nanoparticles on Duckweed(Lemna minor L.) and Analysis on Its Aggregation and Dissolution

Institute of Scientific and Technical Information of China (English)

胡长伟; 刘旭

2012-01-01

The extensive production and application of nanoparticles increase the risk of their environmental release. In this study, duckweed {Lemna minor L.) was exposed to ZnO nanoparticles at different doses(0, 1, 10 mg·L‐1 and 50 mg·L‐1) for 7 d. The influences of the nanoparticles on D665/D665a(ratio of chlorophyll and phoeophytin) and activities of SOD, CAT, POD and Na+K+-ATPase were investigated. In addition, aggregation and dissolution of ZnO nanoparticles were tested. The results showed that the activities of SOD, CAT and POD were significantly increased at 50 mg·L‐1 nanoparticle concentration and decreased when treated with ZnSO4 (Zn2+ 10 mg·L‐1), indicative of an antioxidant stress from the nanoparticles. Whereas, D665/D665a and the activity of Na+K+-ATPase were significantly suppressed. ZnO nanoparticles were inclined to aggregate and precipitate in the culture media, and all nanoparticles settled within 12 h. The concentrations of Zn2+ dissolved from the nanoparticles in the 1 mg·L‐1, 10 mg·L‐1 and 50 mg·L‐1 groups were 0.62 mg·L‐1, 1.86 mg·L‐1 and 2.76 mg·L‐1, respectively, and they were not in proportion to the nanoparticles added to the culture media. The results indicated that 50 mg · L‐1 nanoparticles could bring an evident stress to duckweed(Lemna minor L.). The source of toxicity may mainly be the Zn2+ released by the ZnO nanoparticles.%纳米颗粒的大量生产和应用增加了其环境释放风险,为此以不同浓度的纳米ZnO(O、1、10 mg·L-1和50 mg·L-1)处理浮萍(Lemna minor L.)7 d,分析了纳米颗粒对植物D665/D665a值(叶绿素与脱镁叶绿素的比率)以及超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和Na+K+-ATP酶(Na+K+-ATPase)活性的影响,并对纳米ZnO的聚集性与溶解性进行了测试.研究结果显示,浓度为50 mg· L-1的纳米颗粒显著抑制D665/D665a�

Potential of some aquatic plants for removal of arsenic from wastewater by green technology

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Mohammed Barznji Dana A.

2015-03-01

Full Text Available Phytoremediation or green technology is counted among the successful and effective biological contaminated water treatment techniques. Basically, the concept of this green, cost-effective, simple, environmentally nondisruptive method consists in using plants and microbiological processes to reduce contaminants in the ecosystem. Different species from aquatic plants (emerged, free-floating, and submerged have been studied to mitigate toxic contaminants such as arsenic, cadmium, chromium, copper, lead, mercury, zinc, etc. Arsenic is one of the most severe toxic elements; it is widely distributed in the environment, usually found in combination with chloride, oxygen, sulphur and metal ions as a result of mineral dissolution from sedimentary or volcanic rocks and the dilution of geothermal water. The effluents from both industrial and agricultural sectors are also regarded as sources to contaminate water. From the accumulation point of view, several aquatic plants have been mentioned as good arsenic accumulators and their performance is evaluated using the green technology method. These include Spirodela polyrhiza, Wolffia globosa, Lemna gibba, L. minor, Eichhornia crassipes, Azolla caroliniana, Azolla filiculoides, Azolla pinnata, Ceratophyllum demersum and Pistia stratiotes. The up-to-date information illustrated in this review paper generates knowledge about the ability of some common aquatic plants around the globe to remediate arsenic from contaminated water.

Synchrony of plant cellular circadian clocks with heterogeneous properties under light/dark cycles.

Science.gov (United States)

Okada, Masaaki; Muranaka, Tomoaki; Ito, Shogo; Oyama, Tokitaka

2017-03-22

Individual cells in a plant can work independently as circadian clocks, and their properties are the basis of various circadian phenomena. The behaviour of individual cellular clocks in Lemna gibba was orderly under 24-h light/dark cycles despite their heterogeneous free-running periods (FRPs). Here, we reveal the entrainment habits of heterogeneous cellular clocks using non-24-h light/dark cycles (T-cycles). The cellular rhythms of AtCCA1::LUC under T = 16 h cycles showed heterogeneous entrainment that was associated with their heterogeneous FRPs. Under T = 12 h cycles, most cells showed rhythms having ~24-h periods. This suggested that the lower limit of entrainment to the light/dark cycles of heterogeneous cellular circadian clocks is set to a period longer than 12 h, which enables them to be synchronous under ~24-h daily cycles without being perturbed by short light/dark cycles. The entrainment habits of individual cellular clocks are likely to be the basis of the circadian behaviour of plant under the natural day-night cycle with noisy environmental fluctuations. We further suggest that modifications of EARLY FLOWERING3 (ELF3) in individual cells deviate the entrainability to shorter T-cycles possibly by altering both the FRPs and light responsiveness.

Influence of sublethal concentrations of sulfur dioxide on morphology, growth, and product yield of the duckweed Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Fankhauser, H; Brunold, C; Erismann, K H

1976-01-01

There was no disturbance in the growth of Lemna minor L. with a SO/sub 2/ concentration of up to 0.3 ppM in air. A SO/sub 2/ concentration of 0.6 ppM caused an initial depression of the growth rate of about 25 percent, but in the course of adaptation, the rate rose to the values of the control. The average dry weight per frond was not influenced by the SO/sub 2/ fumigation. The initial sporadic appearance of chloroses by fumigation with 0.6 ppM SO/sub 2/ was considered a sign of the proximate toxicity limit for Lemna minor L. With 0.15 ppM SO/sub 2/ in air, the size of the fronds was reduced. The average surface of the fronds was diminished by 0.3 ppM SO/sub 2/ for about 16 percent as compared with the control plants. The protein remained quantitatively unafffected up to a SO/sub 2/ concentration of 0.6 ppM. As a qualitative influence of SO/sub 2/, the nitrogen content of the proteins remained constant, but the sulfur content of the proteins increased. Under 0.3 and 0.6 ppM SO/sub 2/, the starch content decreased immediately by 20 to 30 percent, under 0.15 ppM SO/sub 2/ the decrease reached the same level after a longer time than in the case of the higher concentrations. The SO/sub 2/ concentrations up to 0.6 ppM had no effect on chlorophyll concentration. The contents of C, N, H, P, K, Na, Ca, Mg, Mn, and Fe were not affected by SO/sub 2/ fumigation. It is concluded that SO/sub 2/ may have some effect on product yield, even under low concentrations, without provoking acute damage; the plant is able to adapt by regulation of its metabolism, and enters a new steady state.

Duckweed Lemna minor as a tool for testing toxicity of coal residues and polluted sediments

Energy Technology Data Exchange (ETDEWEB)

Jenner, H.A.; Janssen-Mommen, J.P.M. (Kema Environmental Services, Arnhem (Netherlands))

1993-07-01

Duckweed, Lemna minor, was used for testing single elements and leachates of coal ashes and sediments by expressing growth as surface coverage. The EC50 for the elements Cd, Cu, Zn, As(III), As(V), Se(IV), Se(VI), SeO[sub 2] were 0.86, 2.2, 4.4, 8.4, 297, 21, 67, 37 [mu]M respectively. Leachates were tested of pulverized coal fuel ash (PFA), including 'low NO[sub x]' ashes, coal gasification slag (CGS), and, as a reference, the polluted sediments of a canal. The concentrations of elements in leachates of 'low NO[sub x]' PFA were higher than those in leachates of conventional PFA. The leaching of anions from PFA was quicker than the cations. CGS showed an absolutely minimal element leaching. Comparison of the effects of conventional PFA with sediments from Rotterdam harbor, River Rhine, and the canal shows PFA to be the far less toxic one. The sediment samples from the canal demonstrated strong growth inhibition, probably due to high zinc concentrations originating from industrial activity.

Duckweed Lemna minor as a tool for testing toxicity of coal residues and polluted sediments

Energy Technology Data Exchange (ETDEWEB)

Jenner, H A; Janssen-Mommen, J P.M. [Kema Environmental Services, Arnhem (Netherlands)

1993-07-01

Duckweed, Lemna minor, was used for testing single elements and leachates of coal ashes and sediments by expressing growth as surface coverage. The EC50 for the elements Cd, Cu, Zn, As(III), As(V), Se(IV), Se(VI), SeO[sub 2] were 0.86, 2.2, 4.4, 8.4, 297, 21, 67, 37 [mu]M respectively. Leachates were tested of pulverized coal fuel ash (PFA), including 'low NO[sub x]' ashes, coal gasification slag (CGS), and, as a reference, the polluted sediments of a canal. The concentrations of elements in leachates of 'low NO[sub x]' PFA were higher than those in leachates of conventional PFA. The leaching of anions from PFA was quicker than the cations. CGS showed an absolutely minimal element leaching. Comparison of the effects of conventional PFA with sediments from Rotterdam harbor, River Rhine, and the canal shows PFA to be the far less toxic one. The sediment samples from the canal demonstrated strong growth inhibition, probably due to high zinc concentrations originating from industrial activity.

Phytotoxicity assessment of a methanolic coal dust extract in Lemna minor.

Science.gov (United States)

Coronado-Posada, Nadia; Cabarcas-Montalvo, Maria; Olivero-Verbel, Jesus

2013-09-01

Coal mining generates negative effects on environment, human health, hydrodynamics of mining areas and biodiversity. However, the impacts of this activity are less known in plants. Lemna minor is one of the most commonly used plants in aquatic toxicity tests due to its ubiquitous distribution in ponds and lakes, culture conditions and the free-floating habitat that exposes it to hydrophobic as well as dissolved compounds. The goal of this research was to evaluate the effects of a methanolic coal dust extract on L. minor. Macrophytes were exposed to six different concentrations of coal extract (from 7.81 to 250 mg/L) for 5 days, following the OECD test guideline 221. The coal extract had a half inhibitory concentration (IC50) of 99.66 (184.95-54.59) mg/L for the number of fronds. Several signs of toxicity such as chlorosis, reduction in the size of the fronds, abscission of fronds and roots, and the presence of necrotic tissues were observed at concentrations lower than the IC50. Preliminary Gas Chromatography-Mass Spectrometry analysis of the coal dust extract revealed the presence of several compounds, including, among others, alkanes, carboxylic acids and polycyclic aromatic hydrocarbons (PAHs), these lasts, may be responsible for some of the observed effects. These results demonstrated that coal dust has phytotoxic effects and should not be considered as an inert material. Copyright © 2013 Elsevier Inc. All rights reserved.

Studies on the water quality and biota of a tidal eutrophic creek ...

African Journals Online (AJOL)

... E.monodon, Navicula gracilis, N. mutica, Ulnariaulna, Nitzschia palea, Pinnularia braunii, P. gibba, Microcystis aeruginosa and Spirulina platensis. Of the 15 mudflat algae Nitzschia palea, Pinnularia braunii, P. gibba and Spirulina platensis were environmentally important species. The population of the benthic fauna was ...

Uptake of Cadmium by Lemna minor, a (hyper?- accumulator plant involved in phytoremediation applications

Directory of Open Access Journals (Sweden)

Bianconi D.

2013-04-01

Full Text Available Metal pollution in waters and soils is a major environmental and human health problem. Cadmium (Cd2+ is a heavy metal displaying toxic effects in plants. In this work we studied the potentiality of Lemna minor, a monocotyledonous aquatic macrophyte, to phytoremediate cadmium-polluted waters. The plants were exposed to different cadmium concentrations 0, 13, 22 and 46μM CdSO4 for a period of 24, 48 and 72 hours. Relative growth rates (RGR, bioconcentration factor (BCF, tolerance index (Ti, cadmium uptake in whole plant and maximum efficiency of PSII (Fv/Fm were measured under controlled climate conditions. RGR, Ti and Fv/Fm declined with increasing exposure time and cadmium concentrations, while the BCF and cadmium uptake showed an opposite behavior. Data analysis of RGR, BCF, Tiand FV/FM indicates that L. minor maintains a good capacity of growth, metal bioconcentration, tolerance and efficiency of PSII up to 48h in plants exposed to 13 and 22μM CdSO4. Our results exhibited that L. minor is a good cadmium accumulator and is able to remediate Cd-polluted waters, especially at low Cd concentrations.

Effects of a rhizobacterium on the growth of and chromium remediation by Lemna minor.

Science.gov (United States)

Tang, Jie; Zhang, Ying; Cui, Yan; Ma, Jiong

2015-07-01

Duckweed has shown great potential for both energy and environmental applications, particularly in wastewater treatment and fuel ethanol production. A rhizobacterium, Exiguobacterium sp. MH3, has been reported to associate with the duckweed Lemna minor for symbiotic growth. The aim of this work is to study the effects of rhizobacterium MH3 on L. minor growth and chromium (Cr) remediation. It appeared to have a synergism between the rhizobacterium MH3 and duckweed; the presence of strain MH3 promoted the growth of duckweeds by increasing both the frond number and dry weight of duckweed by more than 30%, while duckweed in turn provided essential carbon source and energy for the growth of rhizobacterium MH3. Under Cr(VI) exposure, particularly at higher Cr(VI) concentrations, Exiguobacterium sp. MH3 significantly alleviated the harmful effects of the stress on the duckweed by promoting duckweed growth and preventing duckweed from excessive uptake of Cr. Potential mechanisms were also discussed in light of the genome sequence of strain MH3, and it was speculated that siderophores and indole-3-acetic acid (IAA) secreted by strain MH3 might contribute to promoting duckweed growth.

Effects of heavy metals on ultrastructure and Hsp70 induction in Lemna minor L. exposed to water along the Sarno River, Italy.

Science.gov (United States)

Basile, A; Sorbo, S; Cardi, M; Lentini, M; Castiglia, D; Cianciullo, P; Conte, B; Loppi, S; Esposito, S

2015-04-01

The effects of freshwater pollution in the highly contaminated river Sarno (Campania, Southern Italy) have been evaluated using bags containing the aquatic plant Lemna minor (Lemnacee, Arales), in order to determine morpho-physiological modifications as a response to pollutants. The exposition of Lemna bags for 7 days on three different sites along the river path showed alterations in chloroplasts and vacuoles shape and organization. Moreover, some specimens were exposed in vitro at the same heavy metal (HM) concentrations measured in the polluted sites of the river, and compared with data from the bag experiment; to verify the dose and time dependent effects, samples were exposed to HM in vitro at concentrations ranging from 10(-6) to 10(-4)M up to 7 days. Transmission electron microscopy (TEM) observations on in vitro plants confirmed that ultrastructural alterations affected most of plastids and the shape of different subcellular structures, namely vacuoles; in in vitro stressed specimens, Heat Shock Proteins 70 (Hsp70) levels changed, in dependence of changing levels of HM measured in different sites along the river path. Thus L. minor exhibited a possible correlation between the levels of HM pollution and Hsp70 occurrence; interestingly, the data presented showed that copper specifically increased Hsp70 levels at concentrations detected in polluted river waters, whereas cadmium and lead did not; on the other side, the latter represent highly toxic elements when specimens were exposed to higher levels in vitro. The effects of specific elements in vitro are compared to those observed in bags exposed along the river path; thus results are examined in order to propose L. minor as an organism able to be utilized to monitor heavy metals pollution; the possibility of using Hsp70s as specific markers of HM pollution is discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Fabrication and characterization of mesoporous activated carbon from Lemna minor using one-step H3PO4 activation for Pb(II) removal

International Nuclear Information System (INIS)

Huang, Yang; Li, Shunxing; Lin, Haibin; Chen, Jianhua

2014-01-01

Graphical abstract: - Highlights: • Activated carbon was prepared from Lemna minor using H 3 PO 4 activation. • Materials have higher mesoporosity (92.2%) and more oxygen and nitrogen-containing functional groups. • Materials can remove Pb(II) rapidly with monolayer adsorption capacity (170.9 mg/g). • The adsorption process fitted to Langmuir isotherm and pseudo-first-order kinetic. • Materials could be used as an economical, efficient adsorbent to remove Pb(II) ions. - Abstract: A low cost and locally available material, Lemna minor, was used to fabricate activated carbon using H 3 PO 4 activation. After H 3 PO 4 activation, the L. minor activated carbons (LACs) possess high mesoporosity (92.2%) and a surface area of 531.9 m 2 /g according to Brunauer–Emmett–Teller (BET) analysis. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometer (XPS) analyses reveal the presence of rich hydroxyl, carboxyl, amide and phosphate functional groups on the LACs surface, leading to facile Pb(II) binding to the surface through strong chemisorptive bonds or ion-exchange. The kinetic and equilibrium data were well described by pseudo-first-order model and Langmuir isotherm, with the maximum monolayer adsorption capacity (q m ) 170.9 mg/g at 25 °C. The intra-particle diffusion mechanism was partially responsible for the adsorption. The adsorption process was spontaneous and endothermic with negative ΔG and positive ΔH. The Pb(II)-loaded LACs could be easily regenerated using 0.1-M HCl and reused for seven cycles without significant adsorption capacity reduction. The maximum percentage removal rate for Pb(II) (20 mg/L) was found to be 91.8% within 30 min, at optimum conditions of pH 6.0 and 25 °C. These suggested that the low-cost LACs could be used as a potential adsorbent in the treatment of lead-contaminated water

Potential utility of environmental DNA for early detection of Eurasian watermilfoil (Myriophyllum spicatum)

Science.gov (United States)

Newton, Jeremy; Sepulveda, Adam; Sylvester, K; Thum, Ryan

2016-01-01

Considering the harmful and irreversible consequences of many biological invasions, early detection of an invasive species is an important step toward protecting ecosystems (Sepulveda et al. 2012). Early detection increases the probability that suppression or eradication efforts will be successful because invasive populations are small and localized (Vander Zanden et al. 2010). However, most invasive species are not detected early because current tools have low detection probabilities when target species are rare and the sampling effort required to achieve acceptable detection capabilities with current tools is seldom tractable (Jerde et al. 2011). As a result, many invasive species go undetected until they are abundant and suppression efforts become costly. Novel DNA-based surveillance tools have recently revolutionized early detection abilities using environmental DNA (eDNA) present in the water (Darling and Mahon 2011, Bohmann et al. 2014). In brief, eDNA monitoring enables the identification of organisms from DNA present and collected in water samples. Aquatic and semiaquatic organisms release DNA contained in sloughed, damaged, or partially decomposed tissue and waste products into the water and molecular techniques allow this eDNA in the water column to be identified from simple and easy-tocollect water samples (Darling and Mahon 2011). Despite limited understanding of the production, persistence, and spread of DNA in water (Barnes et al. 2014), eDNA monitoring has been applied not only to invasive species (Jerde et al. 2011), but also to species that are rare, endangered, or highly elusive (Spear et al. 2014). However, most eDNA research and monitoring has focused on detection of invertebrates and vertebrates and less attentionhas been given to developing eDNA techniques for detecting aquatic invasive plants. Eurasian watermilfoil (EWM; Myriophyllum spicatum L.) is an invasive species for which improved early detection would be particularly helpful. Advanced

Modeling the interaction of light intensity, nutrient concentration and uranium toxicity in Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Zimmer, E.; Horemans, N.; Vandenhove, H. [Belgian Nuclear Research Centre SCK-CEN (Belgium); Cedergreen, N. [University of Copenhagen (Denmark); Jager, T. [Vrije Universiteit Amsterdam (Netherlands)

2014-07-01

Radioecology aims at assessing the effect of radionuclides and radiation on the environment. Since we cannot test every possible environmental situation in the laboratory, we need modeling approaches to extrapolate the results of toxicity assays to environmentally relevant scenarios. Therefore, it is of crucial importance to understand the effect of relevant environmental factors, such as nutrients, temperature and light on the toxicity of the test. Radionuclides are often found to induce the production of reactive oxygen species (ROS). In plants, an overload of ROS can lead to disturbances of the photosynthetic system. Since the light intensity determines the efficiency of the photo-systems in plants, it can be expected to interact with the effect of radionuclides. The nutrient concentration of the test medium determines the physiological state of the plant, affecting in turn the plant's capability of dealing with stress and hence influences the toxicity of the contaminant. To study the interaction of stressors with environmental conditions, mechanistic effect modeling is promoted widely in ecotoxicology. In principle, the modelling aims at a mechanistic understanding of the different processes causing the stress individually, and integrating them in one framework to study their joint effect and possible interaction. We here present a mechanistic effect model for Lemna minor (common duckweed), which is based on Dynamic Energy Budget (DEB) theory. Models based on DEB have been used widely to study the effects of compounds on animals. Due to its general applicability to all types of organisms, it holds potential to be used for comparison of species and compounds in a broad context. Energy uptake from the environment is modeled explicitly, and metabolic rates are set to depend on temperature in DEB models. Therefore, they can be used to extrapolate effects to a wide range of environmentally relevant scenarios. Until now, the DEB research in ecotoxicology has

The Response of Duckweed (Lemna minor L. Roots to Cd and Its Chemical Forms

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Yan Xue

2018-01-01

Full Text Available The response of duckweed (Lemna minor L. roots to Cd and its chemical forms was investigated. The relative root growth rate and concentrations of Cd and its different chemical forms in the root, that is, ethanol-extractable (FE-Cd, HCl-extractable (FHCl-Cd, and residual fractions (Fr-Cd, were quantified. Weibull model was used to unravel the regression between the relative root elongation (RRL with chemical forms of Cd. Parameters assessed catalase (CAT, peroxidases (POD, and superoxide dismutase (SOD, as well as malondialdehyde (MDA and total antioxidant capacity (A-TOC. Our results show that both the relative root growth rate and relative frond number were affected by Cd concentrations. The chemical forms of Cd were influenced by Cd content in the medium. Relative root elongation (RRL showed a significant correlation with chemical forms of Cd. Additionally, POD and SOD increased at lower Cd concentrations followed by a decrease at higher Cd concentrations (at more than 5 μM Cd. Moreover, MDA and A-TOC increased and CAT decreased with increasing Cd exposure. Furthermore, CAT showed a significant correlation with FHCl-Cd. Taken together, it can be concluded that the chemical forms of Cd are statistically significant predictors of Cd toxicity to duckweed and to the other similar aquatic plants.

Uptake and toxicity of arsenic, copper, and silicon in Azolla caroliniana and Lemna minor.

Science.gov (United States)

Rofkar, Jordan R; Dwyer, Daryl F; Bobak, Deanna M

2014-01-01

Here we report on the analysis of two aquatic plant species, Azolla caroliniana and Lemna minor, with respect to tolerance and uptake of co-occurring arsenic, copper, and silicon for use in engineered wetlands. Plants were cultured in nutrient solution that was amended with arsenic (0 or 20 microM), copper (2 or 78 microM), and silicon (0 or 1.8 mM) either singly or in combination. We hypothesized that arsenic and copper would negatively affect the uptake of metals, growth, and pigmentation and that silicon would mitigate those stresses. Tolerance was assessed by measuring growth of biomass and concentrations of chlorophyll and anthocyanins. Both plant species accumulated arsenic, copper, and silicon; L. minor generally had higher levels on a per biomass basis. Arsenic negatively impacted A. caroliniana, causing a 30% decrease in biomass production and an increase in the concentration of anthocyanin. Copper negatively impacted L. minor, causing a 60% decrease in biomass production and a 45% decrease in chlorophyll content. Silicon augmented the impact of arsenic on biomass production in A. caroliniana but mitigated the effect of copper on L. minor. Our results suggest that mixtures of plant species may be needed to maximize uptake of multiple contaminants in engineered wetlands.

Effects of high ammonium level on biomass accumulation of common duckweed Lemna minor L.

Science.gov (United States)

Wang, Wenguo; Yang, Chuang; Tang, Xiaoyu; Gu, Xinjiao; Zhu, Qili; Pan, Ke; Hu, Qichun; Ma, Danwei

2014-12-01

Growing common duckweed Lemna minor L. in diluted livestock wastewater is an alternative option for pollutants removal and consequently the accumulated duckweed biomass can be used for bioenergy production. However, the biomass accumulation can be inhibited by high level of ammonium (NH4 (+)) in non-diluted livestock wastewater and the mechanism of ammonium inhibition is not fully understood. In this study, the effect of high concentration of NH4 (+) on L. minor biomass accumulation was investigated using NH4 (+) as sole source of nitrogen (N). NH4 (+)-induced toxicity symptoms were observed when L. minor was exposed to high concentrations of ammonium nitrogen (NH4 (+)-N) after a 7-day cultivation. L. minor exposed to the NH4 (+)-N concentration of 840 mg l(-1) exhibited reduced relative growth rate, contents of carbon (C) and photosynthetic pigments, and C/N ratio. Ammonium irons were inhibitory to the synthesis of photosynthetic pigments and caused C/N imbalance in L. minor. These symptoms could further cause premature senescence of the fronds, and restrain their reproduction, growth and biomass accumulation. L. minor could grow at NH4 (+)-N concentrations of 7-84 mg l(-1) and the optimal NH4 (+)-N concentration was 28 mg l(-1).

Effects of coronatine elicitation on growth and metabolic profiles of Lemna paucicostata culture.

Directory of Open Access Journals (Sweden)

Jin-Young Kim

Full Text Available In this study, the effects of coronatine treatment on the growth, comprehensive metabolic profiles, and productivity of bioactive compounds, including phenolics and phytosterols, in whole plant cultures of Lemna paucicostata were investigated using gas chromatography-mass spectrometry (GC-MS coupled with multivariate statistical analysis. To determine the optimal timing of coronatine elicitation, coronatine was added on days 0, 23, and 28 after inoculation. The total growth of L. paucicostata was not significantly different between the coronatine treated groups and the control. The coronatine treatment in L. paucicostata induced increases in the content of hydroxycinnamic acids, such as caffeic acid, isoferulic acid, ρ-coumaric acid, sinapic acid, and phytosterols, such as campesterol and β-sitosterol. The productivity of these useful metabolites was highest when coronatine was added on day 0 and harvested on day 32. These results suggest that coronatine treatment on day 0 activates the phenolic and phytosterol biosynthetic pathways in L. paucicostata to a greater extent than in the control. To the best of our knowledge, this is the first report to investigate the effects of coronatine on the alteration of metabolism in L. paucicostata based on GC-MS profiling. The results of this research provide a foundation for designing strategies for enhanced production of useful metabolites for pharmaceutical and nutraceutical industries by cultivation of L. paucicostata.

Lemna minor L.: As bioindicator of heavy metal pollution in Skadar lake: Montenegro

Directory of Open Access Journals (Sweden)

Kastratović Vlatko

2015-01-01

Full Text Available The use of aquatic plants to analyze the heavy metal pollution of a lake environment has a number of advantages over the standard chemical methods of the analysis of metal presence in water and sediment. The macrophyta Lemna minor L., sampled from Lake Skadar in Montenegro has been used as a bio-indicator. Floating macrophyte L. minor accumulates metals from water through its submerged roots and floated leaves. The contents of Cd, Cu, Co, Cr, Mn, Ni, Pb, Zn, Sr and V were determined in sediments, water and the plant. The results obtained indicated a very high capacity of L. minor for the accumulation of Mn. In addition, higher Zn concentration was found in root tissue comparing to the sediment. The concentration of the other metals under investigation decreases in the following order: sediment > L. minor(root > L. minor(leaf > water. Higher concentrations of all metals in the tissue of L. minor were observed at the end of the growing season. A higher metal content was recorded in the root compared to the leaf. In descending order, the concentrations in plant tissues were found for the following metals: Mn > Zn > Sr > Cu > Ni > Pb > Co > V > Cr > Cd, while the series of bioaccumulation is, in descending order: Mn > Zn > Ni > Co > Pb > Cu > Cr > V > Sr > Cd.

Light-dark regulation of sulfate assimilation in Lemna minor L. in the presence of o-acetyl-l-serine

International Nuclear Information System (INIS)

Brunold, C.; Neuenschwander, U.

1989-01-01

The effect of light removal and addition of O-acetyl-l-serine (OAS) on sulfate assimilation in Lemna minor L. was analyzed by measuring the extractable activity of adenosine 5'-phosphosulfate sulfotransferase (APSSTase) and the in vivo incorporation of 35 SO 4 2- . After removal of light APSSTase activity decreased to 10% within 24 h in the absence and to 50% in the presence of OAS. Within 24 h total 35 SO 4 2- uptake decreased to 60% without and increased to 130% with OAS compared to light controls. The incorporation of 35 S into cysteine increased 2 times without and 15 times with OAS, labelling of glutathione decreased to 65% and increased to 140%, the one of the protein fraction decreased to 30% and to 20% of the light control in the absence and presence of OAS. Our results indicate that OAS has a regulatory function on the assimilation of sulfate and that protein synthesis is inhibited in the dark

A Nanopore-Structured Nitrogen-Doped Biocarbon Electrocatalyst for Oxygen Reduction from Two-Step Carbonization of Lemna minor Biomass

Science.gov (United States)

Guo, Chaozhong; Li, Zhongbin; Niu, Lidan; Liao, Wenli; Sun, Lingtao; Wen, Bixia; Nie, Yunqing; Cheng, Jing; Chen, Changguo

2016-05-01

So far, the development of highly active and stable carbon-based electrocatalysts for oxygen reduction reaction (ORR) to replace commercial Pt/C catalyst is a hot topic. In this study, a new nanoporous nitrogen-doped carbon material was facilely designed by two-step pyrolysis of the renewable Lemna minor enriched in crude protein under a nitrogen atmosphere. Electrochemical measurements show that the onset potential for ORR on this carbon material is around 0.93 V (versus reversible hydrogen electrode), slightly lower than that on the Pt/C catalyst, but its cycling stability is higher compared to the Pt/C catalyst in an alkaline medium. Besides, the ORR at this catalyst approaches to a four-electron transfer pathway. The obtained ORR performance can be basically attributed to the formation of high contents of pyridinic and graphitic nitrogen atoms inside this catalyst. Thus, this work opens up the path in the ORR catalysis for the design of nitrogen-doped carbon materials utilizing aquatic plants as starting precursors.

Effects of CuO nanoparticles on Lemna minor.

Science.gov (United States)

Song, Guanling; Hou, Wenhua; Gao, Yuan; Wang, Yan; Lin, Lin; Zhang, Zhiwei; Niu, Qiang; Ma, Rulin; Mu, Lati; Wang, Haixia

2016-12-01

Copper dioxide nanoparticles (NPs), which is a kind of important and widely used metal oxide NP, eventually reaches a water body through wastewater and urban runoff. Ecotoxicological studies of this kind of NPs effects on hydrophyte are very limited at present. Lemna minor was exposed to media with different concentrations of CuO NPs, bulk CuO, and two times concentration of Cu 2+ released from CuO NPs in culture media. The changes in plant growth, chlorophyll content, antioxidant defense enzyme activities [i.e., peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) activities], and malondialdehyde (MDA) content were measured in the present study. The particle size of CuO NPs and the zeta potential of CuO NPs and bulk CuO in the culture media were also analyzed to complementally evaluate their toxicity on duckweed. Results showed that CuO NPs inhibited the plant growth at lower concentration than bulk CuO. L. minor roots were easily broken in CuO NPs media under the experimental condition, and the inhibition occurred only partly because CuO NPs released Cu 2+ in the culture media. The POD, SOD, and CAT activities of L. minor increased when the plants were exposed to CuO NPs, bulk CuO NPs and two times the concentration of Cu 2+ released from CuO NPs in culture media, but the increase of these enzymes were the highest in CuO NPs media among the three kinds of materials. The MDA content was significantly increased compared with that of the control from 50 mg L -1 CuO NP concentration in culture media. CuO NPs has more toxicity on L. minor compared with that of bulk CuO, and the inhibition occurred only partly because released Cu 2+ in the culture media. The plant accumulated more reactive oxygen species in the CuO NP media than in the same concentration of bulk CuO. The plant cell encountered serious damage when the CuO NP concentration reached 50 mg L -1 in culture media. The toxicology of CuO NP on hydrophytes must be considered because that hydrophytes

浮萍(Lemna aequinoctialis)干粉对Pb2+的吸附%Biosorption of Pb2+ by Dried Powder of Duckweed (Lemna aequinoctialis)

Institute of Scientific and Technical Information of China (English)

陈兰钗; 方扬; 靳艳玲; 陈谦; 赵永贵; 肖瑶; 赵海

2013-01-01

为开发高效去除重金属铅(Pb2+)污染的生物吸附剂,以浮萍(Lemna aequinoctialis)干粉为吸附剂原料,通过单因素实验研究了该吸附剂吸附Pb2+的主要影响因素;利用吸附动力学方程和等温吸附方程对实验数据进行拟合;并采用红外光谱分析仪研究了吸附前后吸附剂表面的化学基团变化.结果表明,对吸附效果影响显著的因素有溶液初始pH值、吸附剂颗粒大小和Pb2+初始浓度;参与吸附pb2+的基团可能是吸附剂所含糖类中的羟基及酰胺中的氨基;其吸附行为符合准二级动力学方程,相关系数R2为0.999 95,k2为3.65 g min-1mg-1;等温吸附曲线符合Freundlich方程,浮萍对Pb2+的吸附量在高达56.79 mg/g时仍未达到吸附饱和点.本研究表明L.aequinoctialis干粉作为一种新型生物吸附剂,对Pb2+的吸附条件要求不严格,吸附速率快,吸附容量大,在较宽的条件范围内都可达到较高的去除率.图5表2参31

Lemna minor tolerance to metal-working fluid residues: implications for rhizoremediation.

Science.gov (United States)

Grijalbo, L; Becerril, J M; Barrutia, O; Gutierrez-Mañero, J; Lucas Garcia, J A

2016-07-01

For the first time in the literature, duckweed (Lemna minor) tolerance (alone or in combination with a consortium of bacteria) to spent metal-working fluid (MWF) was assessed, together with its capacity to reduce the chemical oxygen demand (COD) of this residue. In a preliminary study, L. minor response to pre-treated MWF residue (ptMWF) and vacuum-distilled MWF water (MWFw) was tested. Plants were able to grow in both residues at different COD levels tested (up to 2300 mg·l(-1) ), showing few toxicity symptoms (mainly growth inhibition). Plant response to MWFw was more regular and dose responsive than when exposed to ptMWF. Moreover, COD reduction was less significant in ptMWF. Thus, based on these preliminary results, a second study was conducted using MWFw to test the effectiveness of inoculation with a bacterial consortium isolated from a membrane bioreactor fed with the same residue. After 5 days of exposure, COD in solutions containing inoculated plants was significantly lower than in non-inoculated ones. Moreover, inoculation reduced β+γ-tocopherol levels in MWFw-exposed plants, suggesting pollutant imposed stress was reduced. We therefore conclude from that L. minor is highly tolerant to spent MWF residues and that this species can be very useful, together with the appropriate bacterial consortium, in reducing COD of this residue under local legislation limits and thus minimise its potential environmental impact. Interestingly, the lipophilic antioxidant tocopherol (especially the sum of β+γ isomers) proved to be an effective plant biomarker of pollution. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Effect of zinc ions on nutrient removal and growth of Lemna aequinoctialis from anaerobically digested swine wastewater.

Science.gov (United States)

Zhou, Qi; Lin, Yan; Li, Xiang; Yang, Chunping; Han, Zhenfeng; Zeng, Guangming; Lu, Li; He, Shanying

2018-02-01

The effect of Zn 2+ on ammonium and phosphorous removal and duckweed growth was evaluated for treatment of anaerobically digested swine wastewater (ADSW) at various initial Zn 2+ concentrations ranging from 1.0 to 15mg/L. Lemna aequinoctialis taken from a local pond was selected for the treatment, and its fresh weight and contents of proteins, photosynthetic pigments, and vitamin E were examined. Results showed that the optimal Zn 2+ concentration was 5.0mg/L for NH 3 -N and TP removal, the duckweed growth, and the accumulation of proteins in the duckweed. A maximum content of photosynthetic pigments increased with the increase of initial Zn 2+ concentration, and it arrived earlier for a higher concentration of Zn 2+ . Vitamin E content in the duckweed reached 4.5mg/kg at 15mg/L Zn 2+ in 12-day cultivation, which showed the potential for producing and harvesting a high value-added product of vitamin E by culturing duckweed in ADSW. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Lemna minor growth inhibition test as basis to evaluate radiation or radionuclide-induced effects on freshwater plants

Energy Technology Data Exchange (ETDEWEB)

Horemans, N.; Van Hees, M.; Van Hoeck, A.; Vandenhove, H. [Belgian Nuclear Research Centre, SCK.CEN, Boeretang 200, 2400 Mol (Belgium)

2014-07-01

The setting of radiation protection criteria for wildlife is based on tiered Environmental Risk Assessments (ERA) methods. At various points in such a tiered ERA robust and transparent benchmark values are needed to indicate the levels of exposure that are considered safe to the environment. Although not ideal these benchmark values are today mainly based on laboratory-based experiments in which the toxic effects of radiation or radionuclides to one selected species exposed under standardised growth conditions is studied. As such an eco-toxicity test has been developed for the floating macrophyte Lemna minor that can be used to test the effect of different chemicals in freshwater. Here the use of this test to estimate effects of radiation or radionuclides and its relevance to the environment will be discussed. First single dose response curves are shown that were set up according to the guidelines for gamma, uranium and as a reference also cadmium. According to the guidelines growth inhibition can be calculated on different endpoints like frond number and frond area. The choice of this endpoint seems to be of major importance as dependent on the stressor significant shifts in the EC50 values, the concentration giving 50% effect, were observed. For gamma radiation a recovery experiment was set up in irradiated plants were allowed to grow again for 7 days in control conditions. It was shown that plant growth rate did not catch up with that of the non-irradiated group. On the contrary, plant cultures that showed a growth inhibition above 40% immediately after irradiation completely collapsed during the recovery period indicating no recovery from the gamma induced damage and resulting in a 3-fold lower EC50 value after 7 days recovery. The relevance of these data to the environment will be further discussed. Finally the influence of different cations on the uranium speciation and toxicity are studied. These experiments are the first steps to set up a biotic ligand

Fitorremediación mediante el uso de dos especies vegetales Lemna minor (Lenteja de agua), y Eichornia crassipes (Jacinto de agua) en aguas residuales producto de la actividad minera

OpenAIRE

Jaramillo Jumbo, Mariuxi Del Cisne; Flores Campoverde, Edison Darío

2012-01-01

La contaminación del agua con metales pesados es un problema de gran importancia, aunque existen varios métodos convencionales para su remoción estos son muy costosos por lo que la fitorremediación es una alternativa que utiliza plantas para reducir la concentración de dichos contaminantes. En este trabajo se determinó la capacidad de absorción del mercurio mediante el uso de las macrófitas acuáticas Eichornia crassipes y Lemna minor en diferentes condiciones experimentales. A las macrófit...

Study on the mechanism of allelopathic influence on cyanobacteria and chlorophytes by submerged macrophyte (Myriophyllum spicatum) and its secretion

International Nuclear Information System (INIS)

Zhu Junying; Liu Biyun; Wang Jing; Gao Yunni; Wu Zhenbin

2010-01-01

For revealing the mechanism of allelopathic influence on phytoplankton by aquatic macrophytes, the growth and photosynthetic activities of cyanobacteria Microcystis aeruginosa and the chlorophyte Selenastrum capricornutum were investigated when they coexisted with submerged macrophyte Myriophyllum spicatum and were exposed to allelopathic polyphenols: pyrogallic acid (PA), gallic acid (GA), ellagic acid (EA) and (+)-catechin (CA). According to the results of coexistence assays, the non-photochemical quenching (NPQ) and effective quantum efficiency (YII) of M. aeruginosa were affected earlier and more rapidly than the cell density. However, the influence of M. spicatum on S. capricornutum was not found. When the Toxicity Index (TI) was applied to evaluate the combined effects of binary and multiple mixtures of polyphenols, it was found that the four tested polyphenols with the proportion identified in the M. spicatum-cultured solution were observed to present synergistic effect (0.36-0.49) according to the cell density, NPQ and YII of M. aeruginosa. With the combined effects of polyphenols on S. capricornutum, only additive action (0.52-1.62) was found. On the other hand, PA (2.97 mg L -1 ), GA (2.65 mg L -1 ) caused significant reductions of photosystem II (PSII) and whole electron transport chain activities of M. aeruginosa by 71.43 and 18.37%, 70.95 and 40.77% (P < 0.05), respectively, after 24-h exposure, but no inhibition effect was found in S. capricornutum. The dark respiration and photosystem I (PSI) activities of M. aeruginosa were significantly increased by exposure to PA and GA (P < 0.05). Nevertheless, EA and CA had no influence on the electron transport activities of the tested organisms. These results indicate that the reduction in photosynthetic activity of M. aeruginosa and the synergistic effect of allelochemicals may be two important causes for the inhibition of undesired phytoplankton by submersed macrophytes in natural aquatic ecosystems, and

Study on the mechanism of allelopathic influence on cyanobacteria and chlorophytes by submerged macrophyte (Myriophyllum spicatum) and its secretion

Energy Technology Data Exchange (ETDEWEB)

Zhu Junying [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Liu Biyun [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Wang Jing; Gao Yunni [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China); Wu Zhenbin, E-mail: wuzb@ihb.ac.cn [State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072 (China)

2010-06-10

For revealing the mechanism of allelopathic influence on phytoplankton by aquatic macrophytes, the growth and photosynthetic activities of cyanobacteria Microcystis aeruginosa and the chlorophyte Selenastrum capricornutum were investigated when they coexisted with submerged macrophyte Myriophyllum spicatum and were exposed to allelopathic polyphenols: pyrogallic acid (PA), gallic acid (GA), ellagic acid (EA) and (+)-catechin (CA). According to the results of coexistence assays, the non-photochemical quenching (NPQ) and effective quantum efficiency (YII) of M. aeruginosa were affected earlier and more rapidly than the cell density. However, the influence of M. spicatum on S. capricornutum was not found. When the Toxicity Index (TI) was applied to evaluate the combined effects of binary and multiple mixtures of polyphenols, it was found that the four tested polyphenols with the proportion identified in the M. spicatum-cultured solution were observed to present synergistic effect (0.36-0.49) according to the cell density, NPQ and YII of M. aeruginosa. With the combined effects of polyphenols on S. capricornutum, only additive action (0.52-1.62) was found. On the other hand, PA (2.97 mg L{sup -1}), GA (2.65 mg L{sup -1}) caused significant reductions of photosystem II (PSII) and whole electron transport chain activities of M. aeruginosa by 71.43 and 18.37%, 70.95 and 40.77% (P < 0.05), respectively, after 24-h exposure, but no inhibition effect was found in S. capricornutum. The dark respiration and photosystem I (PSI) activities of M. aeruginosa were significantly increased by exposure to PA and GA (P < 0.05). Nevertheless, EA and CA had no influence on the electron transport activities of the tested organisms. These results indicate that the reduction in photosynthetic activity of M. aeruginosa and the synergistic effect of allelochemicals may be two important causes for the inhibition of undesired phytoplankton by submersed macrophytes in natural aquatic ecosystems

Integrated Evaluation and Indication of Water Quality by Lemna paucicostata%稀脉萍(Lemna paucicostata)对水质的综合评价和指示作用

Institute of Scientific and Technical Information of China (English)

李天煜

2008-01-01

为探讨利用我国本土植物进行水质综合评价和指示的可行性,试验研究了我国特有的浮萍属植物--稀脉萍(Lemna paucicostata)对不同来源水(自来水、雨水为唯一来源的池塘水、接纳多种排放废水的湖水及垃圾填埋场渗滤液)水质的综合评价和指示效果.结果表明,1)就不同来源水而言,随着水质的下降(自来水、池塘水、湖水、渗滤液),稀脉萍叶状体和群体7d相对增殖率(相对于对照)均逐渐降低;2)就某一污水而言,随着水质的下降(渗滤液稀释4096-128倍),稀脉萍叶状体7d相对增殖率逐渐降低,而群体相对增殖率没有明显变化规律.以上结果提示.稀脉萍对水质具有一定的评价和指示作用,其叶状体相对增殖率可应用于水质的生物学监测和综合评价.

Phytoremediation of anatoxin-a by aquatic macrophyte Lemna trisulca L.

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Kaminski, Ariel; Bober, Beata; Chrapusta, Ewelina; Bialczyk, Jan

2014-10-01

The neurotoxin anatoxin-a (ANTX-a), one of the most common cyanotoxin, poses a health risk to people and can be lethal to aquatic organisms. This paper presents results on its bioremediation by the aquatic macrophyte Lemna trisulca. We show that the plant is resistant to the harmful impact of toxin and is capable of removing ANTX-a from water. Some of the ANTX-a concentrations which were used in our experiments were much higher than those found in natural conditions. The exposition of L. trisulca to 2.5 μg ANTX-a/mL did not affect its biomass accumulation within 24 d. Significant decreases in biomass content by 21% and 30% were demonstrated in samples cultivated in media containing 12.5 μg ANTX-a/mL after 18 and 24 day of experiment, respectively. One gram of fresh weight (f.w.) of L. trisulca cultured for 14 d in the media containing 50 μg ANTX-a removed 95% of the initial toxin concentration; for media with 250 μg ANTX-a, 86% was removed. In tests of ANTX-a binding stability and degradation we transferred the macrophyte to fresh media without added toxin; within 14 d the content of accumulated ANTX-a in the macrophyte decreased by 76% (from initial 19.3 μg ANTX-a/gf.w.), 71% (from 37.3 μg ANTX-a/g f.w.) and 47% (from 63.7 μg ANTX-a/g f.w.). The quantity of ANTX-a released to media was minimal: from 3.5% to 5.1% of the initial bioaccumulated value. The data show that part of the ANTX-a was degraded. Mass spectra analyses did not indicate transformation of ANTX-a to already known forms. These findings suggest that L. trisulca has much potential as a phytoremediation agent for stabilization of aquatic environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Experimental tests of priority effects and light availability on relative performance of Myriophyllum spicatum and Elodea nuttallii propagules in artificial stream channels.

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Emily P Zefferman

Full Text Available Submersed macrophytes have important ecological functions in many streams, but fostering growth of beneficial native species while suppressing weedy invasives may be challenging. Two approaches commonly used in management of terrestrial plant communities may be useful in this context: (1 altering resource availability and (2 establishing desirable species before weeds can invade (priority effects. However, these approaches are rarely used in aquatic systems, despite widespread need for sustainable solutions to aquatic weed problems. In artificial stream channels in California, USA, I conducted experiments with asexual propagules of non-native invasive Myriophyllum spicatum (Eurasian watermilfoil and native Elodea nuttallii (western waterweed to address the questions: (1 How does light availability affect relative performance of the two species?; (2 Does planting the native earlier than the invasive decrease survival or growth rate of the invasive?; and (3 Do light level and priority effects interact? The relative performance between E. nuttallii and M. spicatum had an interesting and unexpected pattern: M. spicatum had higher growth rates than E. nuttallii in the zero and medium shade levels, but had similar performance in the low and high shade levels. This pattern is most likely the result of E. nutallii's sensitivity to both very low and very high light, and M. spicatum's sensitivity to very low light only. Native priority did not significantly affect growth rate or survival of M. spicatum, possibly because of unexpectedly poor growth of the E. nuttallii planted early. This study suggests that altering light levels could be effective in reducing growth of an invasive macrophyte, and for changing the competitive balance between a native and a non-native species in the establishment phase. Further investigations into the use of priority effects and resource alteration for submersed macrophyte management are warranted, given their mixed results

Experimental tests of priority effects and light availability on relative performance of Myriophyllum spicatum and Elodea nuttallii propagules in artificial stream channels.

Science.gov (United States)

Zefferman, Emily P

2015-01-01

Submersed macrophytes have important ecological functions in many streams, but fostering growth of beneficial native species while suppressing weedy invasives may be challenging. Two approaches commonly used in management of terrestrial plant communities may be useful in this context: (1) altering resource availability and (2) establishing desirable species before weeds can invade (priority effects). However, these approaches are rarely used in aquatic systems, despite widespread need for sustainable solutions to aquatic weed problems. In artificial stream channels in California, USA, I conducted experiments with asexual propagules of non-native invasive Myriophyllum spicatum (Eurasian watermilfoil) and native Elodea nuttallii (western waterweed) to address the questions: (1) How does light availability affect relative performance of the two species?; (2) Does planting the native earlier than the invasive decrease survival or growth rate of the invasive?; and (3) Do light level and priority effects interact? The relative performance between E. nuttallii and M. spicatum had an interesting and unexpected pattern: M. spicatum had higher growth rates than E. nuttallii in the zero and medium shade levels, but had similar performance in the low and high shade levels. This pattern is most likely the result of E. nutallii's sensitivity to both very low and very high light, and M. spicatum's sensitivity to very low light only. Native priority did not significantly affect growth rate or survival of M. spicatum, possibly because of unexpectedly poor growth of the E. nuttallii planted early. This study suggests that altering light levels could be effective in reducing growth of an invasive macrophyte, and for changing the competitive balance between a native and a non-native species in the establishment phase. Further investigations into the use of priority effects and resource alteration for submersed macrophyte management are warranted, given their mixed results in other

Uranium and cadmium provoke different oxidative stress responses in Lemna minor L.

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Horemans, N; Van Hees, M; Van Hoeck, A; Saenen, E; De Meutter, T; Nauts, R; Blust, R; Vandenhove, H

2015-01-01

Common duckweed (Lemna minor L.) is ideally suited to test the impact of metals on freshwater vascular plants. Literature on cadmium (Cd) and uranium (U) oxidative responses in L. minor are sparse or, for U, non-existent. It was hypothesised that both metals impose concentration-dependent oxidative stress and growth retardation on L. minor. Using a standardised 7-day growth inhibition test, the adverse impact of these metals on L. minor growth was confirmed, with EC50 values for Cd and U of 24.1 ± 2.8 and 29.5 ± 1.9 μm, respectively, and EC10 values of 1.5 ± 0.2 and 6.5 ± 0.9 μm, respectively. The metal-induced oxidative stress response was compared through assessing the activity of different antioxidative enzymes [catalase, glutathione reductase, superoxide dismutase (SOD), ascorbate peroxidase (APOD), guaiacol peroxidase (GPOD) and syringaldizyne peroxidase (SPOD)]. Significant changes in almost all antioxidative enzymes indicated their importance in counteracting the U- and Cd-imposed oxidative burden. However, some striking differences were also observed. For activity of APODs and SODs, a biphasic but opposite response at low Cd compared to U concentrations was found. In addition, Cd (0.5-20 μm) strongly enhanced plant GPOD activity, whereas U inhibited it. Finally, in contrast to Cd, U up to 10 μm increased the level of chlorophyll a and b and carotenoids. In conclusion, although U and Cd induce similar growth arrest in L. minor, the U-induced oxidative stress responses, studied here for the first time, differ greatly from those of Cd. © 2014 German Botanical Society and The Royal Botanical Society of the Netherlands.

Enantioselective accumulation, metabolism and phytoremediation of lactofen by aquatic macrophyte Lemna minor.

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Wang, Fang; Yi, Xiaotong; Qu, Han; Chen, Li; Liu, Donghui; Wang, Peng; Zhou, Zhiqiang

2017-09-01

Pesticides are frequently detected in water bodies due to the agricultural application, which may pose impacts on aquatic organisms. The enantioselective bioaccumulation and metabolism of the herbicide lactofen in aquatic floating macrophyte Lemna minor (L. minor) were studied and the potential L. minor phytoremediation was investigated. Ultra-high performance liquid chromatography - tandem mass spectrometry (UHPLC-MS-MS) analysis for lactofen and its two known metabolites in L. minor was performed. The initial concentrations of racemic lactofen, R-lactofen and S-lactofen were all 30μgL -1 in the growth solution. The distribution of lactofen and its metabolites in growth solution and L. minor was determined throughout a 5-d laboratory trial. It was observed that S-lactofen was preferentially taken up and metabolized in L. minor. After rac-lactofen exposure, the accumulation amount of S-lactofen was approximately 3-fold more than that of R-lactofen in L. minor and the metabolism rate of S-lactofen (T 1/2 =0.92 d) was significantly faster than R-lactofen (T 1/2 =1.55 d). L. minor could only slightly accelerate the metabolism and removal of lactofen in the growth solution. As for the metabolites, desethyl lactofen was found to be the major metabolite in L. minor and the growth solution, whereas the metabolite acifluorfene was undetectable. No interconversion of the two enantiomers was observed after individual enantiomer exposure, indicating they were configurationally stable. The findings of this work represented that the accumulation and metabolism of lactofen in L. minor were enantioselective, and L. minor had limited capacity for the removal of lactofen and its metabolite in water. Copyright © 2017. Published by Elsevier Inc.

Ciprofloxacin induces oxidative stress in duckweed (Lemna minor L.): Implications for energy metabolism and antibiotic-uptake ability.

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Gomes, Marcelo Pedrosa; Gonçalves, Cíntia Almeida; de Brito, Júlio César Moreira; Souza, Amanda Miranda; da Silva Cruz, Fernanda Vieira; Bicalho, Elisa Monteze; Figueredo, Cleber Cunha; Garcia, Queila Souza

2017-04-15

We investigate the physiological responses and antibiotic-uptake capacity of Lemna minor exposed to ciprofloxacin. Ciprofloxacin (Cipro) induced toxic effects and hormesis in plants by significantly modifying photosynthesis and respiration pathways. A toxic effect was induced by a concentration ≥1.05mg ciprofloxacin l -1 while hormesis occurs at the lowest concentration studied (0.75mg ciprofloxacin l -1 ). By impairing normal electron flow in the respiratory electron transport chain, ciprofloxacin induces hydrogen peroxide (H 2 O 2 ) production. The ability of plants to cope with H 2 O 2 accumulation using antioxidant systems resulted in stimulation/deleterious effects to photosynthesis by Cipro. Cipro-induced oxidative stress was also associated with the ability of L. minor plants to uptake the antibiotic and, therefore, with plant-uptake capacity. Our results indicate that instead of being a photosystem II binding molecule, Cipro induces oxidative stress by targeting the mitochondrial ETC, which would explain the observed effects of the antibiotic on non-target eukaryotic organisms. The selection of plants species with a high capacity to tolerate oxidative stress may constitute a strategy to be used in Cipro-remediation programs. Copyright © 2017 Elsevier B.V. All rights reserved.

Tolerance and hyperaccumulation of a mixture of heavy metals (Cu, Pb, Hg, and Zn) by four aquatic macrophytes.

Science.gov (United States)

Romero-Hernández, Jorge Alberto; Amaya-Chávez, Araceli; Balderas-Hernández, Patricia; Roa-Morales, Gabriela; González-Rivas, Nelly; Balderas-Plata, Miguel Ángel

2017-03-04

In the present investigation, four macrophytes, namely Typha latifolia (L.), Lemna minor (L.), Eichhornia crassipes (Mart.) Solms-Laubach, and Myriophyllum aquaticum (Vell.) Verdc, were evaluated for their heavy metal (Cu, Pb, Hg, and Zn) hyperaccumulation potential under laboratory conditions. Tolerance analyses were performed for 7 days of exposure at five different treatments of the metals mixture (Cu +2 , Hg +2 , Pb +2 , and Zn +2 ). The production of chlorophyll and carotenoids was determined at the end of each treatment. L. minor revealed to be sensitive, because it did not survive in all the tested concentrations after 72 hours of exposure. E. crassipes and M. aquaticum displayed the highest tolerance to the metals mixture. For the most tolerant species of aquatic macrophytes, The removal kinetics of E. crassipes and M. aquaticum was carried out, using the following mixture of metals: Cu (0.5 mg/L) and Hg, Pb, and Zn 0.25 mg/L. The obtained results revealed that E. crassipes can remove 99.80% of Cu, 97.88% of Pb, 99.53% of Hg, and 94.37% of Zn. M. aquaticum withdraws 95.2% of Cu, 94.28% of Pb, 99.19% of Hg, and 91.91% of Zn. The obtained results suggest that these two species of macrophytes could be used for the phytoremediation of this mixture of heavy metals from the polluted water bodies.

Impact of acidification and eutrophication on macrophyte communities in soft waters in The Netherlands

Energy Technology Data Exchange (ETDEWEB)

Roelofs, J G.M.

1983-01-01

During the last decades a strong decline has been noticed in the number of waters dominated by Littorellion species, mostly isoetids such as Lobelia dortmanna L., Isoetes lacustris L. and Littorella uniflora (L.) Aschers. Sixty-eight waters, which were known to be dominated by L. uniflora after 1950 were investigated. In 1980, L. uniflora appeared to be absent or to have strongly decreased in 53 (78%) of the waters. In 41 of them, Littorella had been replaced by submerged Juncus bulbosus L. and/or Sphagnum spp. These changes seem to have been caused by changed inorganic carbon budgets as a consequence of acidification. In the remaining 12 waters, eutrophication of the water and/or sediment seems to be responsible for the changes in the plant communities. Enrichment with phosphate of the mineral sediment alone, leads to luxurious growth of submerged, rooted macrophyte species such as Myriophyllum alterniflorum DC and Ranunculus peltatus Schrank, whereas phosphate-enrichment of both sediment and water leads to luxurious growth of pleustophytes such as Riccia fluitans L. and Lemna minor L. in small, shallow waters, and to plankton bloom and luxurious growth of epiphytes in larger, deeper waters. In these cases light limitation seems to be responsible for the disappearance or decline of the Littorellion species. 41 references, 1 figure, 4 tables.

Insights into phytase-containing transgenic Lemna minor (L.) as a novel feed additive.

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Ghosh, Mrinmoy; Sharma, Neelesh; Gera, Meeta; Kim, Nameun; Huynh, Do; Zhang, Jiaojiao; Min, Taesun; Sodhi, Simrinder Singh; Kim, Min Bae; Rekha, V P B; Ko, Sukmin; Jeong, Dong Kee

2018-04-01

This study assessed the effect of supplementation of novel transgenic phytase on growth performance and bone mineralization in Korean native broiler chickens. The experiment was designed using four dietary groups: those with a diet supplemented with (A) recombinant phytase, (B) transgenic phytase from the plant Lemna minor, (C) or wild-type L. minor as well as (D) a control group that was supplemented with commercially available feed. Three hundred 1-day-old Korean native broiler chicks were used and divided into these four dietary treatment groups having three replicates of 25 birds each (n = 75). The results showed increases in growth performance and bone mineralization in Groups B and C; compared with Groups A and D. Hematological analyses revealed notable contrasts in erythrocyte sedimentation rate, red blood cell count, and hemoglobin levels among the experimental groups, whereas no impacts of dietary treatment were observed on total eosinophil, lymphocyte, heterophil, monocyte, and basophil levels. The relative expression profiling of candidate genes showed that the genes involved in growth response, meat quality, and P-Ca metabolism were significantly highly expressed in the phytase-supplemented groups. Hence, it is suggested that dietary supplementation with transgenic phytase plant L. minor for enhancing growth performance is a promising new approach in the broiler feed industry. To the best of our knowledge, we report here the most comprehensive analysis using a broiler model that provides a workable platform for further research on the cost-effective production of feed with different compositions that might be beneficial in the livestock feed industry.

LES PROLIFÉRATIONS VÉGÉTALES AQUATIQUES EN FRANCE : CARACTÈRES BIOLOGIQUES ET ÉCOLOGIQUES DES PRINCIPALES ESPÈCES ET MILIEUX PROPICES. I. BILAN D’UNE SYNTHÈSE BIBLIOGRAPHIQUE.

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PELTRE M. C.

2002-04-01

Full Text Available La gestion des milieux aquatiques touchés par des proliférations végétales rencontre de nombreuses difficultés liées à l’appréciation des déséquilibres induits. Parmi celles-ci figure l’évaluation de l’intensité des phénomènes, tant à l’échelle spatiale que temporelle, et celle des nuisances qui réduisent la satisfaction des usages. Un inventaire des principaux groupes de végétaux concernés, considérés comme des « espèces à risque de prolifération » a été dressé après examen de divers constats recensés sur le territoire français. Ce sont notamment des macro-algues, des cyanobactéries, des phanérogames hydrophytes autochtones comme Ranunculus sp., Potamogeton sp., Myriophyllum sp., Ceratophyllum sp., Lemna sp., et des hydrophytes introduits comme Elodea sp., Lagarosiphon sp., Ludwigia sp., Myriophyllum aquaticum, certains hélophytes et deux espèces rivulaires exotiques (Fallopia japonica et Impatiens glandulifera. Leurs potentialités importantes de développement et de propagation s’expliquent par leurs stratégies biologiques, dont certaines adaptations morphologiques et physiologiques et divers moyens de multiplication végétative. Les milieux propices aux proliférations présentent des conditions environnementales particulières : fort éclairement souvent lié à une faible profondeur et à un échauffement des eaux, conditions hydrologiques stables, minéralisation moyenne à forte, niveau trophique souvent élevé. La conjonction de ces deux composantes (espèce à risque et milieu propice, crée ainsi les conditions d’une prolifération et définit des situations à risque minimal ou maximal. Ces connaissances concourent à une meilleure définition des situations de risque de prolifération et peuvent fournir des informations utiles quant aux conditions et aux limites d’application des techniques de gestion et de contrôle de ces phénomènes.

Thorough removal of inorganic and organic mercury from aqueous solutions by adsorption on Lemna minor powder

Energy Technology Data Exchange (ETDEWEB)

Li Shunxing, E-mail: lishunxing@fjzs.edu.cn [Department of Chemistry, Zhangzhou Normal University, Zhangzhou 363000 (China); Fujian Province University Key Laboratory of Analytical Science, Zhangzhou Normal University, Zhangzhou (China); Zheng Fengying; Huang Yang [Department of Chemistry, Zhangzhou Normal University, Zhangzhou 363000 (China); Fujian Province University Key Laboratory of Analytical Science, Zhangzhou Normal University, Zhangzhou (China); Ni Jiancong [Department of Chemistry, Zhangzhou Normal University, Zhangzhou 363000 (China)

2011-02-15

The adsorption ability of duckweed (Lemna minor) powders for removing inorganic and organic mercury (methyl and ethyl mercury) has been studied using cold vapour atomic absorption spectrometry. The optimal adsorption conditions were: (a) the pH value of the solution 7.0 for inorganic and ethyl mercury, 9.0 for methyl mercury, and (b) equilibrium adsorption time 10, 20, and 40 min for inorganic mercury, methyl mercury, and ethyl mercury, respectively. After adsorption by L. minor powder for 40 min, when the initial concentrations of inorganic and organic mercury were under 12.0 {mu}g L{sup -1} and 50.0 {mu}g L{sup -1}, respectively, the residual concentrations of mercury could meet the criterion of drinking water (1.0 {mu}g L{sup -1}) and the permitted discharge limit of wastewater (10.0 {mu}g L{sup -1}) set by China and USEPA, respectively. Thorough removal of both inorganic and organic mercury from aqueous solutions was reported for the first time. The significant adsorption sites were C-O-P and phosphate groups by the surface electrostatic interactions with aqueous inorganic and organic mercury cations, and then the selective adsorption was resulted from the strong chelating interaction between amine groups and mercury on the surface of L. minor cells.

Thorough removal of inorganic and organic mercury from aqueous solutions by adsorption on Lemna minor powder

International Nuclear Information System (INIS)

Li Shunxing; Zheng Fengying; Huang Yang; Ni Jiancong

2011-01-01

The adsorption ability of duckweed (Lemna minor) powders for removing inorganic and organic mercury (methyl and ethyl mercury) has been studied using cold vapour atomic absorption spectrometry. The optimal adsorption conditions were: (a) the pH value of the solution 7.0 for inorganic and ethyl mercury, 9.0 for methyl mercury, and (b) equilibrium adsorption time 10, 20, and 40 min for inorganic mercury, methyl mercury, and ethyl mercury, respectively. After adsorption by L. minor powder for 40 min, when the initial concentrations of inorganic and organic mercury were under 12.0 μg L -1 and 50.0 μg L -1 , respectively, the residual concentrations of mercury could meet the criterion of drinking water (1.0 μg L -1 ) and the permitted discharge limit of wastewater (10.0 μg L -1 ) set by China and USEPA, respectively. Thorough removal of both inorganic and organic mercury from aqueous solutions was reported for the first time. The significant adsorption sites were C-O-P and phosphate groups by the surface electrostatic interactions with aqueous inorganic and organic mercury cations, and then the selective adsorption was resulted from the strong chelating interaction between amine groups and mercury on the surface of L. minor cells.

The toxicity of zinc oxide nanoparticles to Lemna minor (L.) is predominantly caused by dissolved Zn.

Science.gov (United States)

Chen, Xiaolin; O'Halloran, John; Jansen, Marcel A K

2016-05-01

Nano-ZnO particles have been reported to be toxic to many aquatic organisms, although it is debated whether this is caused by nanoparticles per sé, or rather dissolved Zn. This study investigated the role of dissolved Zn in nano-ZnO toxicity to Lemna minor. The technical approach was based on modulating nano-ZnO dissolution by either modifying the pH of the growth medium and/or surface coating of nano-ZnO, and measuring resulting impacts on L. minor growth and physiology. Results show rapid and total dissolution of nano-ZnO in the medium (pH 4.5). Quantitatively similar toxic effects were found when L. minor was exposed to nano-ZnO or the "dissolved Zn equivalent of dissolved nano-ZnO". The conclusion that nano-ZnO toxicity is primarily caused by dissolved Zn was further supported by the observation that phytotoxicity was absent on medium with higher pH-values (>7), where dissolution of nano-ZnO almost ceased. Similarly, the reduced toxicity of coated nano-ZnO, which displays a slower Zn dissolution, is also consistent with a major role for dissolved Zn in nano-ZnO toxicity. Copyright © 2016 Elsevier B.V. All rights reserved.

Fabrication and characterization of mesoporous activated carbon from Lemna minor using one-step H{sub 3}PO{sub 4} activation for Pb(II) removal

Energy Technology Data Exchange (ETDEWEB)

Huang, Yang, E-mail: zzsfxyhy@163.com; Li, Shunxing; Lin, Haibin; Chen, Jianhua

2014-10-30

Graphical abstract: - Highlights: • Activated carbon was prepared from Lemna minor using H{sub 3}PO{sub 4} activation. • Materials have higher mesoporosity (92.2%) and more oxygen and nitrogen-containing functional groups. • Materials can remove Pb(II) rapidly with monolayer adsorption capacity (170.9 mg/g). • The adsorption process fitted to Langmuir isotherm and pseudo-first-order kinetic. • Materials could be used as an economical, efficient adsorbent to remove Pb(II) ions. - Abstract: A low cost and locally available material, Lemna minor, was used to fabricate activated carbon using H{sub 3}PO{sub 4} activation. After H{sub 3}PO{sub 4} activation, the L. minor activated carbons (LACs) possess high mesoporosity (92.2%) and a surface area of 531.9 m{sup 2}/g according to Brunauer–Emmett–Teller (BET) analysis. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometer (XPS) analyses reveal the presence of rich hydroxyl, carboxyl, amide and phosphate functional groups on the LACs surface, leading to facile Pb(II) binding to the surface through strong chemisorptive bonds or ion-exchange. The kinetic and equilibrium data were well described by pseudo-first-order model and Langmuir isotherm, with the maximum monolayer adsorption capacity (q{sub m}) 170.9 mg/g at 25 °C. The intra-particle diffusion mechanism was partially responsible for the adsorption. The adsorption process was spontaneous and endothermic with negative ΔG and positive ΔH. The Pb(II)-loaded LACs could be easily regenerated using 0.1-M HCl and reused for seven cycles without significant adsorption capacity reduction. The maximum percentage removal rate for Pb(II) (20 mg/L) was found to be 91.8% within 30 min, at optimum conditions of pH 6.0 and 25 °C. These suggested that the low-cost LACs could be used as a potential adsorbent in the treatment of lead-contaminated water.

Avaliação de lagoas de Lemnas (Landoltia punctata) para o polimento de esgoto sanitário e fixação de gás carbônico

OpenAIRE

Brugnago, Natália

2014-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Ambiental, Florianópolis, 2014. A fim de mitigar o problema da poluição das águas, as lagoas de lemnas têm sido consideradas como uma tecnologia eficiente e de baixo custo, sendo então aplicadas para o tratamento de esgoto sanitário e agroindustrial. A elevada eficiência na remoção de nutrientes (N e P) é uma das principais vantagens dessa tecnologia. Além disso, a b...

Field based investigation on phytoremediation potentials of Lemna minor and Azolla filiculoides in tropical, semiarid regions: Case of Ethiopia.

Science.gov (United States)

Amare, Elfu; Kebede, Fassil; Berihu, Tesfay; Mulat, Worku

2017-10-16

This study investigated the concurrent accumulation of eight heavy metals by two floating aquatic macrophytes (Lemna minor and Azolla filiculoides) cultivated in ambient media and blended wastewaters in the semiarid regions of Ethiopia. Both species accumulated heavy metals in varying degrees with a significant concentration gradient within the immediate water media. Highest bioconcentration factor was determined for Mn and Fe in both plants. Results revealed that L. minor was high phytoaccumulator for Fe, Mn, Zn and Co but moderate for Cd, Cu, Ni and Cr. On the other hand, A. filiculoides was a high accumulator for Fe, Mn, Zn and Cu, but its potency was moderate for Co, Cr and Ni, but lower for Cd. Both species exhibited significant difference in accumulating Co, Zn and Mn (p < 0.05). In general, the bioconcentration factors for both plants were comparable within the same treatment. In this study, stronger associations between the heavy metal concentrations in the plant tissues and in the grown water media were observed for A. filiculoides.

Response and recovery of the macrophytes Elodea canadensis and Myriophyllum spicatum following a pulse exposure to the herbicide iofensulfuron-sodium in outdoor stream mesocosms.

Science.gov (United States)

Wieczorek, Matthias V; Bakanov, Nikita; Lagadic, Laurent; Bruns, Eric; Schulz, Ralf

2017-04-01

Interest in stream mesocosms has recently revived for higher tier aquatic macrophyte risk assessment of plant protection products mainly because 1) the highest predicted environmental concentrations for the assessment of effects are frequently derived from stream scenarios, and 2) they allow an effect assessment using stream-typical pulse exposures. Therefore, the present stream mesocosm study used an herbicide pulse exposure and evaluated the responses of Elodea canadensis and Myriophyllum spicatum. Macrophytes were exposed for 24 h to 1 μg/L, 3 μg/L, 10 μg/L, and 30 μg/L of the herbicide iofensulfuron-sodium with a subsequent recovery period of 42 d. Biological endpoints were growth rates of the main, side, and total shoot length, the shoot number, the maximum root length, and the dry weight. The total shoot length was identified as the most sensitive endpoint; the growth rate of the total shoot length was inhibited by up to 66% and 45% in M. spicatum and E. canadensis, respectively. The lowest no observed effect concentrations (NOECs) were observed at day 7 and/or day 14 after herbicide treatment and were 1 μg/L for M. spicatum and 3 μg/L for E. canadensis. The no-observed-ecologically-adverse-effect concentrations (NOEAECs) were 10 μg/L and 30 μg/L for M. spicatum and E. canadensis, respectively. Such or similar mesocosm designs are useful to simulate typical stream exposures and estimate herbicide effects on aquatic macrophytes in stream systems. Environ Toxicol Chem 2017;36:1090-1100. © 2016 SETAC. © 2016 SETAC.

The use of Lemna Minor (duckweed) to control the water quality in relation to coal residues. Gebruik van eendekroos voor het bewaken van de waterkwaliteit in relatie met kolenreststoffen

Energy Technology Data Exchange (ETDEWEB)

Janssen-Mommen, J P.M.; Jenner, H A [KEMA Milieu Services, Arnhem (Netherlands)

1993-01-01

Lemna Minor can be applied as a phytomonitor in a standardized test for ecotoxicological investigations of leachate extracts of coal residues and (water)soils. A standardized test method has been developed for fortnight toxicity experiments. The toxicity and the uptake of individual elements were studied in accumulation experiments.Special attention is paid to the impact of the factors complexation, interaction and speciation on the biological availability of the elements. Coal residues and water soils are leached and the leachate extracts are tested for growth restraint by means of the test method. It appears that the use of duckweed as a phytomonitor is a technically simple and reliable method

Sorption of thorium (Ⅳ) from aqueous solutions by melamine modified lemna minor%三聚氰胺化学改性浮萍吸附重金属钍(Ⅳ)研究

Institute of Scientific and Technical Information of China (English)

杨司坤; 吴玮琳; 侯小娟; 吴方评; 陆建生; 向开祥

2017-01-01

采用生物吸附法去除废水中Th(Ⅳ)离子,研究了水生浮萍化学改性后吸附Th(Ⅳ)的行为特性、吸附模型及吸附机理.以浮萍、三聚氰胺和甲醛为原料,通过接枝反应制得三聚氰胺改性浮萍(MELM),能更好的吸附钍离子.结果表明:常温常压下,pH为5.5,吸附剂MELM为0.03 g,Th(Ⅳ)初始浓度为80 mg·L1,反应60 min时,最大吸附率为97.4％,对应吸附量为129.88 mg·g-1,吸附量比未经处理的浮萍(最优吸附条件下,吸附量为22.83 mg·g-1)吸附量要大.通过Langmuir、Freundlich、Temkin 3种等温吸附模型对数据进行拟合,Langmuir模型能更好的描述吸附剂MELM对Th(Ⅳ)的平衡吸附行为,同时吸附过程能很好的用准二级反应动力学来解释.此外,FTIR实验数据表明,吸附剂MELM表面上氨基、羟基和羰基是主要的作用基团.%Thorium(Ⅳ) ions sorption is investigated by melamine treated lemna minor from wastewater.Lemna minor reacted with melamine dissolve in formaldehyde (MELM) exhibited the highest thorium(Ⅳ) ions uptake capacity.The sorption process was optimized at pH 5.5,equilibrium time 60 min,initial Th(Ⅳ) mass concentration 80 mg·L-1 and adsorbent dose 0.03 g with 97.4％ of removal efficiency and 129.88 mg· g-1 of adsorption capacity,which is obviously greater than that (22.83 mg· g-1) of the untreated lemna minor for Th (Ⅳ) biosorption under the condition of optimization.The experimental data are analyzed by using isotherm and kinetic models.Kinetic data follow the pseudo-second-order model and equilibrium data agree very well with the Langmuir model.In addition,FTIR analysis indicates that hydroxyl,amino,and carbonyl groups act as the important roles in the adsorption process.

PRODUCCIÓN DE LA MACRÓFITA ACUÁTICA Lemna perpusilla UTILIZANDO AGUA RESIDUAL DE UNA INSTALACIÓN PORCINA, CON PROPÓSITOS PARA PRODUCCIÓN DE BIOMASA PARA ACUACULTURA

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Pablos Reyes DP

2011-01-01

Full Text Available Una problemática ambiental impor- tante en instalaciones porcinas es la producción de excretas con alta concentración de nutrientes y su deposición en el ecosistema. Una alternativa para la biorremediación de dicha problemática es utilizar las excretas para la producción de plantas acuáticas que tengan una alta tasa de captación de nutrientes, tal como Lemna perpusilla. En el presente estudio se desarrollaron dos experimentos con el objetivo de estudiar el efecto de la época del año y el tiempo de cosecha sobre la biomasa, composición química y el rendimiento de nutrientes. En el experimento I (enero a abril se utilizó una dosis de fertilización de 20 Lm-2 por cada 20 días y se manejó una densidad de siembra de 200 gm-2, realizando cosechas cada 10 días. Mientras que en el experimento II (mayo a ju- nio se utilizó la misma dosis de fertilización y densidad de siembra, pero cosechando cada seis días. Durante el desarrollo experimental (enero-junio Lemna perpusilla presentó bajo contenido de materia seca (6.87 a 8.87% y fi- bra (11.67 a 12.89%, pero alto contenido de proteína (26.02 a 27.41%. Se determinó que la época y tiempo de cosecha afectan significati- vamente la cosecha total, composición química y rendimiento de nutrientes. Las variables cli- máticas que más influyeron sobre la cosecha total fueron las horas luz y precipitación. Mien- tras que el rendimiento en nutrientes es princi- palmente afectada por la temperatura, hume- dad relativa, horas luz y precipitación.

Interaction of Sulfate Assimilation with Carbon and Nitrogen Metabolism in Lemna minor1

Science.gov (United States)

Kopriva, Stanislav; Suter, Marianne; von Ballmoos, Peter; Hesse, Holger; Krähenbühl, Urs; Rennenberg, Heinz; Brunold, Christian

2002-01-01

Cysteine synthesis from sulfide and O-acetyl-l-serine (OAS) is a reaction interconnecting sulfate, nitrogen, and carbon assimilation. Using Lemna minor, we analyzed the effects of omission of CO2 from the atmosphere and simultaneous application of alternative carbon sources on adenosine 5′-phosphosulfate reductase (APR) and nitrate reductase (NR), the key enzymes of sulfate and nitrate assimilation, respectively. Incubation in air without CO2 led to severe decrease in APR and NR activities and mRNA levels, but ribulose-1,5-bisphosphate carboxylase/oxygenase was not considerably affected. Simultaneous addition of sucrose (Suc) prevented the reduction in enzyme activities, but not in mRNA levels. OAS, a known regulator of sulfate assimilation, could also attenuate the effect of missing CO2 on APR, but did not affect NR. When the plants were subjected to normal air after a 24-h pretreatment in air without CO2, APR and NR activities and mRNA levels recovered within the next 24 h. The addition of Suc and glucose in air without CO2 also recovered both enzyme activities, with OAS again influenced only APR. 35SO42− feeding showed that treatment in air without CO2 severely inhibited sulfate uptake and the flux through sulfate assimilation. After a resupply of normal air or the addition of Suc, incorporation of 35S into proteins and glutathione greatly increased. OAS treatment resulted in high labeling of cysteine; the incorporation of 35S in proteins and glutathione was much less increased compared with treatment with normal air or Suc. These results corroborate the tight interconnection of sulfate, nitrate, and carbon assimilation. PMID:12428005

Low-temperature X-ray microanalysis of the differentiating vascular tissue in root tips of Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Echlin, P [Univ. of Cambridge, England; Lai, C E; Hayes, T L

1982-06-01

The fracture faces of bulk-frozen tissue offer a number of advantages for the analysis of diffusible elements. They are easy to prepare, remain uncontaminated, and, unlike most frozen-hydrated sections, can be shown to exist in a fully hydrated state throughout examination and analysis. Root tips of Lemna minor briefly treated with a polymeric cryoprotectant are quench frozen in melting nitrogen. Fractures are prepared using the AMRAY Biochamber, lightly etched if necessary to reveal surface detail and carbon coated while maintaining the specimen at 110 K. The frozen-hydrated fracture faces are analyzed at 110 K using the P/B ratio method which is less sensitive to changes in surface geometry and variations in beam current. The method has been used to investigate the distribution of seven elements (Na/sup +/, Mg/sup + +/, P, S, Cl/sup -/, K/sup +/ and Ca/sup + +/) in the developing vascular tissue of the root tip. The microprobe can measure relative elemental ratios at the cellular level and the results from this present study reveal important variations in different parts of the root. The younger, more actively dividing cells, appear to have a slightly higher concentration of diffusible ions in comparison to the somewhat older tissues which have begun to differentiate into what are presumed to be functional vascular elements.

Sewage treatment in integrated system of UASB reactor and duckweed pond and reuse for aquaculture.

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Mohapatra, D P; Ghangrekar, M M; Mitra, A; Brar, S K

2012-06-01

The performance of a laboratory-scale upflow anaerobic sludge blanket (UASB) reactor and a duckweed pond containing Lemna gibba was investigated for suitability for treating effluent for use in aquaculture. While treating low-strength sewage having a chemical oxygen demand (COD) of typically less than 200 mg/L, with an increase in hydraulic retention time (HRT) from 10.04 to 33.49 h, COD removal efficiency of the UASB reactor decreased owing to a decrease in organic loading rate (OLR) causing poor mixing in the reactor. However, even at the lower OLR (0.475 kg COD/(m3 x d)), the UASB reactor gave a removal efficiency of 68% for COD and 74% for biochemical oxygen demand (BOD). The maximum COD, BOD, ammonia-nitrogen and phosphate removal efficiencies of the duckweed pond were 40.77%, 38.01%, 61.87% and 88.57%, respectively. Decreasing the OLR by increasing the HRT resulted in an increase in efficiency of the duckweed pond for removal of ammonia-nitrogen and phosphate. The OLR of 0.005 kg COD/(m2 x d) and HRT of 108 h in the duckweed pond satisfied aquaculture quality requirements. A specific growth rate of 0.23% was observed for tilapia fish fed with duckweed harvested from the duckweed pond. The economic analysis proved that it was beneficial to use the integrated system of a UASB reactor and a duckweed pond for treatment of sewage.

Trapetum natantis Müller et Görs 1960 in hydromeliorative facilities in Serbia

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Dejana Džigurski

2013-04-01

Full Text Available Trapa natans is one of the very few plants that generate so many contrasting views: it is highly endangered in Europe, invasive in North America and Australia, yet highly valued in India and China due to its nutritional and medical properties. Its endangered status in most of the Europe has prompted significant conservation efforts aimed at retention and expansion of its population. T. natans is currently on the red list of many European countries and is included under “Appendix I” of the “Convention on the conservation of European wildlife and natural habitats” (Bern Convention and IPA list (IPA criterion A, threatened species. The unusual circumstances, i.e. endangered status of T. natans in the region on one hand and its expansion in Serbia on the other, are the reason behind this research that aims to present the distribution, floristic composition and ecological conditions of ass. Trapetum natantis stands in hydromeliorative facilities (Serbia, comprised of 28 hydrophytes. In the analyzed stands, based on the long-term phytocenological studies, we have singled out four floristic and ecological groups: the stands in which T. natans predominates, the stands with Ceratophyllum demersum, the stands with lemnids plants (Lemna minor, L. gibba, Spirodela polyrrhiza and Salvinia natans and the stands with Hydrocharis morsus-ranae. In the researched localities, the differentiation of ass. Trapetum natantis stands is predetermined by the phosphorus and nitrate content, as well as pH and BOD5 levels.

Differential oxidative and antioxidative response of duckweed Lemna minor toward plant growth promoting/inhibiting bacteria.

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Ishizawa, Hidehiro; Kuroda, Masashi; Morikawa, Masaaki; Ike, Michihiko

2017-09-01

Bacteria colonizing the plant rhizosphere are believed to positively or negatively affect the host plant productivity. This feature has inspired researchers to engineer such interactions to enhance crop production. However, it remains to be elucidated whether rhizobacteria influences plant oxidative stress vis-a-vis other environmental stressors, and whether such influence is associated with their growth promoting/inhibiting ability. In this study, two plant growth-promoting bacteria (PGPB) and two plant growth-inhibiting bacteria (PGIB) were separately inoculated into axenic duckweed (Lemna minor) culture under laboratory conditions for 4 and 8 days in order to investigate their effects on plant oxidative stress and antioxidant activities. As previously characterized, the inoculation of PGPB and PGIB strains accelerated and reduced the growth of L. minor, respectively. After 4 and 8 days of cultivation, compared to the PGPB strains, the PGIB strains induced larger amounts of O 2 •- , H 2 O 2 , and malondialdehyde (MDA) in duckweed, although all bacterial strains consistently increased O 2 •- content by two times more than that in the aseptic control plants. Activities of five antioxidant enzymes were also elevated by the inoculation of PGIB, confirming the severe oxidative stress condition in plants. These results suggest that the surface attached bacteria affect differently on host oxidative stress and its response, which degree correlates negatively to their effects on plant growth. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Effects of epiphytic algae on biomass and physiology of Myriophyllum spicatum L. with the increase of nitrogen and phosphorus availability in the water body.

Science.gov (United States)

Song, Yu-Zhi; Wang, Jin-Qi; Gao, Yong-Xia

2017-04-01

The disappearance of submerged vascular macrophytes in shallow eutrophic lakes is a common phenomenon in the world. To explore the mechanism of the decline in submerged macrophyte abundance due to the growth of epiphytic algae along a nutrient gradient in eutrophic water, a 2 × 3 factorial experiment was performed over 4 weeks with the submerged macrophyte (Myriophyllum spicatum L.) by determining the plant's biomass and some physiological indexes, such as chlorophyll (Chl) content, malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity in the leaves of M. spicatum L. on days 7, 14, 21, and 28, which are based on three groups of nitrogen and phosphorus levels in the water body (N-P [mg L -1 ]: NP1 0.5-0.05, NP2 2.5-0.25, NP3 4.5-0.45) and two levels of epiphytic algae (the epiphytic algae group and the control group). Epiphytic algal biomass was also assayed. The results indicated that epiphytic algal biomass remarkably enhanced in the course of the experiment with elevated levels of nitrogen and phosphorus in the water. Under the same level of nutrient condition, plants' biomass accumulation and Chl content were higher in the control group than that in the epiphytic algae group, respectively, while MDA content and SOD activity in the former were lower than that in the latter. The influences of epiphytic algae on the biomass accumulation and Chl content and MDA content became greater and greater with elevated levels of nutrients. In general, in this experiment, water nutrients promoted the growth of both epiphytic algae and submerged plants, while the growth of epiphytic algae hindered submerged macrophytes' growth by reducing Chl content and promoting peroxidation of membrane lipids in plants.

Accumulation of 99Tc in duckweed Lemna minor L. as a function of growth rate and 99Tc concentration

International Nuclear Information System (INIS)

Hattink, J.; Wolterbeek, H.Th.

2001-01-01

This study focuses on the question of whether short-term studies can be used to forecast the accumulation of the long-lived fission product 99 Tc in duckweed, Lemna minor L., grown in the field; in other words, are the accumulation parameters independent of changing growth rates typical of natural populations of duckweed. Two processes determine the 99 Tc accumulation: (i) uptake and release of 99 TcO 4 - , characterised by a concentration factor, K d , and (ii) first-order reduction and complexation of Tc VII , characterised by k red . At various 99 Tc concentrations, the growth, total Tc and TcO 4 - accumulation were monitored over 10 days; parameters were fitted and compared with earlier results. Both K d and k red turn out to be independent of time, concentration and growth rate up to a concentration of 10 -6 mol l -1 99 TcO 4 - . Concentrations above this level result in toxic effects. The Tc accumulation in field populations of duckweed at Tc concentrations which generally occur in the environment can be forecasted by using the results from short-term experiments

Las Haloragaceae de Cuba

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Betancourt Gandul, Martha

1999-12-01

Full Text Available A study of the Haloragaceae in Cuba is presented. The presence of Proserpinaca palustris, P. pectinata. Myriophyllum laxum and M. pinnatum is confirmed, and the possible extinction of M. sparsiflorum is suggestedEstudio de la familia Haloragaceae en Cuba. Se confirma la existencia de Proserpinaca palustris, P. pectinata. Myriophyllum laxum y M, pinnatum, y se plantea la posible extinción de M. sparsiflorum.

Molluscan indicator species and their potential use in ecological status assessment using species distribution modeling.

Science.gov (United States)

Moraitis, Manos L; Tsikopoulou, Irini; Geropoulos, Antonios; Dimitriou, Panagiotis D; Papageorgiou, Nafsika; Giannoulaki, Marianna; Valavanis, Vasilis D; Karakassis, Ioannis

2018-05-24

Marine habitat assessment using indicator species through Species Distribution Modeling (SDM) was investigated. The bivalves: Corbula gibba and Flexopecten hyalinus were the indicator species characterizing disturbed and undisturbed areas respectively in terms of chlorophyll a concentration in Greece. The habitat suitability maps of these species reflected the overall ecological status of the area. The C. gibba model successfully predicted the occurrence of this species in areas with increased physical disturbance driven by chlorophyll a concentration, whereas the habitat map for F. hyalinus showed an increased probability of occurrence in chlorophyll-poor areas, affected mainly by salinity. We advocate the use of C. gibba as a proxy for eutrophication and the incorporation of this species in monitoring studies through SDM methods. For the Mediterranean Sea we suggest the use of F. hyalinus in SDM as an indicator of environmental stability and a possible forecasting tool for salinity fluctuations. Copyright © 2018 Elsevier Ltd. All rights reserved.

镉和乙草胺单一及复合污染对浮萍生长的影响%Effects of Single and Combined Pollution of Cadmium and Acetochlor on the Growth of Lemna minor L.

Institute of Scientific and Technical Information of China (English)

黄河; 姜萍萍

2011-01-01

[目的]研究镉和乙草胺单一及复合污染对浮萍生长的影响.[方法]采用室内培养的方法,研究了镉和乙草胺单一及复合污染对浮萍生物量(鲜重)、叶绿素含量、可溶性糖含量、游离脯氨酸含量和丙二醛(MDA)含量的影响.[结果]在镉和乙草胺单一及复合污染条件下,浮萍的鲜重和叶绿素含量在处理后第5天显著下降,且随处理时间的延长,下降趋势更明显；可溶性糖含量在处理后第5天增加近29％,但在处理后第10和15天,随处理浓度的增加可溶性糖含量下降了近23％和28％；而脯氨酸和丙二醛含量随处理浓度的增加而显著增加.[结论]复合污染加剧了对浮萍的毒害作用.%[Objective ] The aim was to study the effects of cadmium ( Cd ) and acetochlor ( AC ) on Lemna minar L. Growth. [ Method ] Hydroponics culture experiments were conducted with Lemna minar L. In room, the single and joint toxic effects of cadmium and acetochlor on the biomass (fresh weight) , chlorophyll, soluble sugar, free praline, and malondialdehyde( MDA) contents in the leaves of Lemna minor L. Were studied. [ Result] The results showed that under the condition of single and combined pollution,the biomass were decreased significantly as compared to the control after 5 days treatment,and decreased more significantly with the time; the soluble sugar content increased by 29% after 5 days treatment,but then decreased by 23% and 28% .after 10 days and 15 days treatment respectively. The free proline and MDA content were increased significantly with the concentration. [ Conclusion] The results showed shown that the effects of combined pollution were heavier than those of single pollution.

Pb-induced avoidance-like chloroplast movements in fronds of Lemna trisulca L.

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Sławomir Samardakiewicz

Full Text Available Lead ions are particularly dangerous to the photosynthetic apparatus, but little is known about the effects of trace metals, including Pb, on regulation of chloroplast redistribution. In this study a new effect of lead on chloroplast distribution patterns and movements was demonstrated in mesophyll cells of a small-sized aquatic angiosperm Lemna trisulca L. (star duckweed. An analysis of confocal microscopy images of L. trisulca fronds treated with lead (15 μM Pb2+, 24 h in darkness or in weak white light revealed an enhanced accumulation of chloroplasts in the profile position along the anticlinal cell walls, in comparison to untreated plants. The rearrangement of chloroplasts in their response to lead ions in darkness was similar to the avoidance response of chloroplasts in plants treated with strong white light. Transmission electron microscopy X-ray microanalysis showed that intracellular chloroplast arrangement was independent of the location of Pb deposits, suggesting that lead causes redistribution of chloroplasts, which looks like a light-induced avoidance response, but is not a real avoidance response to the metal. Furthermore, a similar redistribution of chloroplasts in L. trisulca cells in darkness was observed also under the influence of exogenously applied hydrogen peroxide (H2O2. In addition, we detected an enhanced accumulation of endogenous H2O2 after treatment of plants with lead. Interestingly, H2O2-specific scavenger catalase partly abolished the Pb-induced chloroplast response. These results suggest that H2O2 can be involved in the avoidance-like movement of chloroplasts induced by lead. Analysis of photometric measurements revealed also strong inhibition (but not complete of blue-light-induced chloroplast movements by lead. This inhibition may result from disturbances in the actin cytoskeleton, as we observed fragmentation and disappearance of actin filaments around chloroplasts. Results of this study show that the

Ecotoxicological assessments show sucralose and fluoxetine affect the aquatic plant, Lemna minor.

Science.gov (United States)

Amy-Sagers, Cherisse; Reinhardt, Keith; Larson, Danelle M

2017-04-01

Pharmaceuticals and personal care products (PPCP) are prevalent in aquatic systems, yet the fate and impacts on aquatic plants needs quantification for many compounds. We measured and detected sucralose (an artificial sweetener), fluoxetine (an antidepressant), and other PPCP in the Portneuf River in Idaho, USA, where Lemna minor (an aquatic plant in the environment and used in ecotoxicology studies) naturally occurs. Sucralose was hypothesized to negatively affect photosynthesis and growth of L. minor because sucralose is a chlorinated molecule that may be toxic or unusable for plant metabolism. A priori hypotheses were not created for fluoxetine due to lack of previous studies examining its impacts on plants. We conducted laboratory ecotoxicological assessments for a large range of concentrations of sucralose and fluoxetine on L. minor physiology and photosynthetic function. Frond green leaf area, root length, growth rate, photosynthetic capacity, and plant carbon isotopic composition (discrimination relative to a standard; δ 13 C) were measured among treatments ranging from 0 to 15000nmol/L-sucralose and 0-323nmol/L-fluoxetine. Contrary to our predictions, sucralose significantly increased green leaf area, photosynthetic capacity, and δ 13 C of L. minor at environmentally relevant concentrations. The increase of δ 13 C from sucralose amendments and an isotope-mixing model indicated substantial sucralose uptake and assimilation within the plant. Unlike humans who cannot break down and utilize sucralose, we documented that L. minor-a mixotrophic plant-can use sucralose as a sugar substitute to increase its green leaf area and photosynthetic capacity. Fluoxetine significantly decreased L. minor root growth, daily growth rate, and asexual reproduction at 323nmol/L-fluoxetine; however, ambiguity remains regarding the mechanisms responsible and the applicability of these extreme concentrations unprecedented in the natural environment. To our knowledge, this was the

Possible ecological risk of two pharmaceuticals diclofenac and paracetamol demonstrated on a model plant Lemna minor.

Science.gov (United States)

Kummerová, Marie; Zezulka, Štěpán; Babula, Petr; Tříska, Jan

2016-01-25

Lemna minor is often used in environmental risk assessment and it can be supposed that usually evaluated parameters will be reliable even for assessing the risk of pharmaceuticals. Subtle changes in duckweed plant number, biomass production, and leaf area size induced by 10-day-exposure to diclofenac (DCF) and paracetamol (PCT) (0.1, 10, and 100 μg/L), excepting 100 μg/L DCF, are in contrast with considerable changes on biochemical and histochemical level. Both drugs caused a decrease in content of photosynthetic pigments (by up to 50%), an increase in non-photochemical quenching (by 65%) and decrease in relative chlorophyll fluorescence decay values (by up to 90% with DCF). Both DCF and especially PCT increased amount of reactive nitrogen and oxygen species in roots. DCF-induced effects included mainly increased lipid peroxidation (by 78%), disturbation in membrane integrity and lowering both oxidoreductase and dehydrogenase activities (by 30%). PCT increased the content of soluble proteins and phenolics. Higher concentrations of both DCF and PCT increased the levels of oxidised ascorbate (by 30%) and oxidised thiols (by up to 84% with DCF). Glutathion-reductase activity was elevated by both pharmaceuticals (nearly by 90%), glutathion-S-transferase activity increased mainly with PCT (by 22%). The early and sensitive indicators of DCF and PCT phytotoxicity stress in duckweed are mainly the changes in biochemical processes, connected with activation of defense mechanisms against oxidative stress. Copyright © 2015 Elsevier B.V. All rights reserved.

Flora of the Mediterranean Rivers in Bulgaria

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Yordanka G. Hristeva

2015-06-01

Full Text Available Species composition and distribution of aquatic bryophytes and vascular plants assemblages in Mediteranean Rivers in Bulgaria are presented in this work. Aquatic macrophytes were studied at thirteen rivers in South Bulgaria during 2014, together with abiotic factors (flow velocity, shading, and substrate type, mean depth and altitude. In total, 73 species were registered, of them 13 bryophytes and 60 vascular plants were identified. Aquatic bryophytes included 10 mosses and 3 liverworts. The recorded bryophytes species refer to 7 families and 12 genera. The most frequently distributed species was Leptodictyum riparium (Hedw. Warnst., followed by Cratoneuron filicinum (Hedw. Spruce and Platyhypnidium riparioides (Hedw. Dixon, Brachythecium rivulare Schimp. and Hygroamblystegium tenax (Hedw. Jenn. The recorded 60 species of vascular plants refer to 25 families and 43 genera. The most common hydrophyte species was Lemna minor L., followed by Ranunculus trichophyllus Chaix, Myriophyllum spicatum L. and Potamogeton nodosus Poir. The most abundant species from the group of helophytes and amphiphytes was Mentha aquatica L., followed by Agrostis stolonifera L. Mentha spicata L., Berula erecta (Huds. Coville, Juncus effusus L., Lycopus europaeus L., Lythrum salicaria L., Phalaris arundinacea L., Ranunculus repens L., Sparganium erectum L., Typha latifolia L., and Veronica anagalis-aquatica L. The majority of studied rivers sites were sunny, with moderate velocity, stony bottom, average depth up to 0.3 m and altitude between 100 and 500 m a.s.l.

Myriophyllum heterophyllum Michx

Czech Academy of Sciences Publication Activity Database

Prančl, Jan

2015-01-01

Roč. 50, č. 1 (2015), s. 75-78 ISSN 1211-5258 R&D Projects: GA ČR GB14-36079G Institutional support: RVO:67985939 Keywords : floristics * new findings * the Czech Republic Subject RIV: EF - Botanics

Performance of the macrophyte Lemna valdiviana in tertiary pig waste treatment and its contribution to the sustainability of swine production

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Flávio R. Lapolli

2008-03-01

Full Text Available The present study aims to contribute to the sustainability of swine production by evaluating usage of the aquatic macrophyte Lemna valdiviana in the tertiary treatment of pig waste. Five assays (1 to 5 in triplicate were conducted using swine effluent with different COD (Chemical Oxygen Demand concentrations: 400, 550, 700, 850 and 1,000mg.L-1, respectively. The trial lasted for 21 days and the evaluated variables were: (a pollutant removal efficiency, (b biomass production and (c plant protein content under the different detention times of 7, 14 and 21 days. In general, assays 1 and 2 (CODs of 400 and 550mg.L-1 presented the best removal efficiencies under a detention time of 21 days. Regarding the purpose of both nutrient removal and production of high protein biomass, assay 3 (COD of 700mg.L-1 showed the best results under 14 days’ detention time (36.81% crude protein. It was established that the use of duckweeds in the tertiary swine waste treatment was able to provide a sustainable alternative regarding its advantages such as effluent polishing, minimization of environmental impact, and production of high protein feed.

Stress responses of duckweed (Lemna minor L.) and water velvet (Azolla filiculoides Lam.) to anionic surfactant sodium-dodecyl-sulphate (SDS).

Science.gov (United States)

Forni, C; Braglia, R; Harren, F J M; Cristescu, S M

2012-04-01

Surfactants are used for several purposes and recently they have attracted the attention for their ability to modify the behavior of other preexistent or co-disposed contaminants, although their use or discharge in wastewaters can represent a real or potential risk for the environment. Lemna minor L. and Azolla filiculoides Lam. are floating aquatic macrophytes, very effective in accumulating several pollutants including sodium dodecyl sulphate (SDS). In this work we evaluated the effects of SDS on these species by determining the stress ethylene production via laser-based trace gas detection, and the activities of enzymes involved in stress response, such as guaiacol peroxidase (G-POD), phenylalanine ammonia-lyase (PAL) and polyphenol-oxidase (PPO). Phenolics content was also determined. The macrophytes were treated with different concentrations of SDS for one week. SDS affected duckweed enzymatic activities and phenol content. While in the fern phenolics amount, PAL, G-POD and PPO activities were not affected by SDS except for 100 ppm SDS, the only concentration that was taken up and not completely degraded. Stress ethylene production was induced only in the fern treated with 50 and 100 ppm SDS. Copyright © 2011 Elsevier B.V. All rights reserved.

Response of Lemna minor L. to short-term cobalt exposure: The effect on photosynthetic electron transport chain and induction of oxidative damage.

Science.gov (United States)

Begović, Lidija; Mlinarić, Selma; Antunović Dunić, Jasenka; Katanić, Zorana; Lončarić, Zdenko; Lepeduš, Hrvoje; Cesar, Vera

2016-06-01

The effect of two concentrations of cobalt (Co(2+)) on photosynthetic activity and antioxidative response in Lemna minor L. were assessed 24, 48 and 72h after the start of the exposure. Higher concentration of cobalt (1mM) induced growth inhibition while lower concentration (0.01mM) increased photosynthetic pigments content. Analysis of chlorophyll a fluorescence transients revealed high sensitivity of photosystem II primary photochemistry to excess of Co(2+) especially at the higher concentration where decreased electron transport beyond primary quinone acceptor QA(-) and impaired function of oxygen evolving complex (OEC) was observed. Due to impairment of OEC, oxygen production was decreased at higher Co(2+) concentration. Activity of superoxide dismutase was mainly inhibited while lipid peroxidation increased, at both concentrations, indicating that cobalt-induced oxidative damage after short exposure and moreover, susceptibility of the membranes in the cell to cobalt toxicity. Results obtained in this study suggest possible application of used parameters as tools in assessment of early damage caused by metals. Copyright © 2016 Elsevier B.V. All rights reserved.

Sodium chloride as a reference substance for the three growth endpoints used in the Lemna minor L. (1753 test

Directory of Open Access Journals (Sweden)

Aline Andrade Godoy

2017-01-01

Full Text Available Lemna sp. growth inhibition test standardized protocols suggest the use of compounds such as 3,5-dichlorophenol as reference substances for checking the test organism’s sensitivity routinely. However, this and other recommended chemicals present risks to human health and to the environment. Sodium chloride (NaCl appears as a less toxic alternative reference substance which has been successfully used in routine ecotoxicological tests. However, the evaluation of this compound in multiple growth endpoints used in the L. minor test, which is required for recommending it as a reference substance for this test organism, has not yet been reported. In the present study, NaCl was tested with L. minor for the growth endpoints frond number, total frond area and fresh weight. Results showed acceptable sensitivity and reproducibility (coefficient of variance < 15.0% for all three of the measured endpoints. Statistically significant differences were observed between the EC50 values calculated based on the three endpoints (p < 0.05. Total frond area was the most sensitive one, with average EC50 value of 2742.80 ± 245.7 mg L-1. It was anticipated that NaCl can be a suitable alternative reference substance and that total frond area should be the endpoint of choice for sensitivity toxicity tests using NaCl.

Effect of graphene oxide on copper stress in Lemna minor L.: evaluating growth, biochemical responses, and nutrient uptake.

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Hu, Changwei; Liu, Lei; Li, Xiuling; Xu, Yundi; Ge, Zhigang; Zhao, Yongjun

2018-01-05

The wide application and unique properties of graphene oxide (GO) make it to interact with other pollutants and subsequently alter their behavior and toxicity. We evaluated the influences of GO at different concentrations (1 and 5mg/L) on copper (Cu) stress in duckweed (Lemna minor L.) GO below a concentration of 5mg/L showed no adverse effects on L. minor. The addition of Cu above 10μM represented a stress condition, which was evidenced by various parameters such as frond number, percent inhibition of growth rate (I r ), total chlorophyll content, dry weight, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). When L. minor was simultaneously exposed to GO and Cu, especially at a GO concentration of 5mg/L and a Cu level above 10μM, the increase of I r and decrease of chlorophyll content were inhibited, suggesting that the Cu stress was diminished in the presence of GO. The addition of Cu alone, ranging between 5 and 20μM, increased Cu, B, Mn, Fe, Co, and Zn uptake, but decreased P uptake. Our results suggest that GO can lessen Cu stress in L. minor via Cu adsorption, thereby protecting the plants from the damaging effects of high Cu concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

Content of biogenic amines in Lemna minor (common duckweed) growing in medium contaminated with tetracycline.

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Baciak, Michał; Sikorski, Łukasz; Piotrowicz-Cieślak, Agnieszka I; Adomas, Barbara

2016-11-01

Aquatic plants are continuously exposed to a variety of stress factors. No data on the impact of antibiotics on the biogenic amines in duckweed (Lemna minor) have been available so far, and such data could be significant, considering the ecological role of this plant in animal food chains. In the tissues of control (non-stressed) nine-day-old duckweed, the following biogenic amines were identified: tyramine, putrescine, cadaverine, spermidine and spermine. Based on the tetracycline contents and the computed EC values, the predicted toxicity units have been calculated. The obtained results demonstrated phytoxicity caused by tetracycline in relation to duckweed growth rate, yield and the contents of chlorophylls a and b. The carotenoid content was not modified by tetracycline. It was found that tetracycline as a water pollutant was a stress factor triggering an increase in the synthesis of amines. Tetracycline at 19, 39 and 78μM concentrations increased biogenic amine synthesis by 3.5 times. Although the content of tyramine increased fourteen times with the highest concentration of the drug (and of spermidine - only three-fold) the increase of spermidine was numerically the highest. Among the biogenic amines the most responsive to tetracycline were spermine and tyramine, while the least affected were putrescine and spermidine. Despite putrescine and spermidine being the least sensitive, their sum of contents increased five-fold compared to the control. These studies suggest that tetracycline in water reservoirs is taken up by L. minor as the antibiotic clearly modifies the metabolism of this plant and it may likely pose a risk. Copyright © 2016 Elsevier B.V. All rights reserved.

Oxidative stress in duckweed (Lemna minor L.) induced by glyphosate: Is the mitochondrial electron transport chain a target of this herbicide?

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Gomes, Marcelo Pedrosa; Juneau, Philippe

2016-11-01

We investigated the physiological responses of Lemna minor plants exposed to glyphosate. The deleterious effects of this herbicide on photosynthesis, respiration, and pigment concentrations were related to glyphosate-induced oxidative stress through hydrogen peroxide (H 2 O 2 ) accumulation. By using photosynthetic and respiratory electron transport chain (ETC) inhibitors we located the primary site of reactive oxygen species (ROS) production in plants exposed to 500 mg glyphosate l -1 . Inhibition of mitochondrial ETC Complex I by rotenone reduced H 2 O 2 concentrations in glyphosate-treated plants. Complex III activity was very sensitive to glyphosate which appears to act much like antimycin A (an inhibitor of mitochondrial ETC Complex III) by shunting electrons from semiquinone to oxygen, with resulting ROS formation. Confocal evaluations for ROS localization showed that ROS are initially produced outside of the chloroplasts upon initial glyphosate exposure. Our results indicate that in addition to interfering with the shikimate pathway, glyphosate can induce oxidative stress in plants through H 2 O 2 formation by targeting the mitochondrial ETC, which would explain its observed effects on non-target organisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

A multigenerational effect of parental age on offspring size but not fitness in common duckweed (Lemna minor).

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Barks, P M; Laird, R A

2016-04-01

Classic theories on the evolution of senescence make the simplifying assumption that all offspring are of equal quality, so that demographic senescence only manifests through declining rates of survival or fecundity. However, there is now evidence that, in addition to declining rates of survival and fecundity, many organisms are subject to age-related declines in the quality of offspring produced (i.e. parental age effects). Recent modelling approaches allow for the incorporation of parental age effects into classic demographic analyses, assuming that such effects are limited to a single generation. Does this 'single-generation' assumption hold? To find out, we conducted a laboratory study with the aquatic plant Lemna minor, a species for which parental age effects have been demonstrated previously. We compared the size and fitness of 423 laboratory-cultured plants (asexually derived ramets) representing various birth orders, and ancestral 'birth-order genealogies'. We found that offspring size and fitness both declined with increasing 'immediate' birth order (i.e. birth order with respect to the immediate parent), but only offspring size was affected by ancestral birth order. Thus, the assumption that parental age effects on offspring fitness are limited to a single generation does in fact hold for L. minor. This result will guide theorists aiming to refine and generalize modelling approaches that incorporate parental age effects into evolutionary theory on senescence. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Effects of exposure to nano and bulk sized TiO2 and CuO in Lemna minor.

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Dolenc Koce, Jasna

2017-10-01

Nanoparticles of TiO 2 and CuO are among most commonly used nanoparticles, and elevated concentrations of them are expected to be found in all environments, including aquatic. A standard growth inhibition test ISO/CD 20079 was used to determine the toxicity of nano sized and larger micro sized (bulk) particles in the concentrations of 0.1, 1, 10, 100 and 1000 μM CuO and TiO 2 on common duckweed (Lemna minor L.). Both nano and bulk CuO particles caused changes in the structure and function of treated plants. The number of fronds and colonies decreased by as much as 78%, the length of roots and fronds decreased by 99% and 14%, respectively. Furthermore, photochemical efficiency was reduced by up to 35%, and the activities of antioxidative enzymes guaiacol peroxidase, ascorbate peroxidase and glutathione reductase increased by more than 240%. The altered physiological state of the CuO exposed plants was also reflected in the elevated occurrence of necrosis and bleaching in the duckweed colonies. Nano sized particles of CuO proved more phytotoxic than bulk particles, and the effects of both studied CuO sizes were concentration dependent. On the other hand, both bulk and nano sized particles of TiO 2 caused no severe phytotoxic effects, there was no concentration dependence and they could be considered as non-harmful to common duckweed. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Recovery of Lemna minor after exposure to sulfadimethoxine irradiated and non-irradiated in a solar simulator.

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Drobniewska, Agata; Wójcik, Dorota; Kapłan, Monika; Adomas, Barbara; Piotrowicz-Cieślak, Agnieszka; Nałęcz-Jawecki, Grzegorz

2017-12-01

Sulfonamides are the second most widely used group of veterinary antibiotics which are often detected in the environment. They are eliminated from freshwaters mainly through photochemical degradation. The toxicity of sulfadimethoxine (SDM) was evaluated with the use of Lemna minor before and after 1- and 4-h irradiation in a SunTest CPS+ solar simulator. Eight endpoints consisting of: number and total area of fronds, fresh weight, chlorophylls a and b, carotenoids, activity of catalase and guaiacol peroxidase, and protein content were determined. The total frond area and chlorophyll b content were the most sensitive endpoints with EC50 of 478 and 554 μg  L -1 , respectively. The activity of guaiacol peroxidase and catalase increased at SDM concentrations higher than 125 and 500 μg  L -1 , respectively. The SDM photodegradation rate for first order kinetics and the half-life were 0.259 h -1 and 2.67  h, respectively. The results show that the toxicity of irradiated solutions was caused by SDM only, and the photoproducts appeared to be either non-toxic or much less toxic to L. minor than the parent compound. To study the recovery potential of L. minor, after 7 days exposure in SDM solutions, the plants were transferred to fresh medium and incubated for the next 7 days. L. minor has the ability to regenerate, but a 7-day recovery phase is not sufficient for it to return to an optimal physiological state.

Sensitivity of the green alga Pediastrum duplex Meyen to allelochemicals is strain-specific and not related to co-occurrence with allelopathic macrophytes.

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Falk Eigemann

Full Text Available Interspecific differences in the response of microalgae to stress have numerous ecological implications. However, little is known of intraspecific sensitivities and the potential role of local genetic adaptation of populations. We compared the allelochemical sensitivity of 23 Pediastrum duplex Meyen strains, a common component of the freshwater phytoplankton. In order to test for local genetic adaptation, strains were isolated from water bodies with and without the allelopathically-active submerged macrophyte Myriophyllum. Strains were assigned to P. duplex on the basis of cell shape and colony morphology and only P. duplex strains that belonged to the same lineage in an ITS rDNA phylogeny were used. Inhibition of strain growth rates and maximum quantum yields of photosystem II were measured after exposure to tannic acid (TA and co-culture with Myriophyllum spicatum. Growth rate inhibition varied over one order of magnitude between the P. duplex strains. There was no correlation between the presence of Myriophyllum in the source location and the sensitivity of the strains to TA or the presence of Myriophyllum, suggesting that at least strong unidirectional local adaptation to Myriophyllum had not taken place in the studied water bodies. The maximum quantum yield of photosystem II of TA exposed algae decreased, whereas the yield of algae exposed to M. spicatum was slightly higher than that of the controls. The ranking of P. duplex strain sensitivities differed between the types of exposure (single additions of TA versus co-existence with M. spicatum and the parameter measured (growth rate versus maximum quantum yield, emphasizing the importance of measuring multiple traits when analysing strain-specific sensitivities towards allelochemicals. The observation that sensitivities to allelochemicals vary widely among strains of a single freshwater algal species should be taken into account if evaluating ecological consequences of allelopathic

Antioxidative stress responses in the floating macrophyte Lemna minor L. with cylindrospermopsin exposure.

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Flores-Rojas, Nelida Cecilia; Esterhuizen-Londt, Maranda; Pflugmacher, Stephan

2015-12-01

Cylindrospermopsin toxicity and oxidative stress have been examined in aquatic animals, however, only a few studies with aquatic plants have been conducted focusing on the potential for bioaccumulation of cylindrospermopsin. The oxidative stress effects caused by cylindrospermopsin on macrophytes have not yet been specifically studied. The oxidative stress response of Lemna minor L. with exposure to cylindrospermopsin, was therefore tested in this study. The hydrogen peroxide concentration together with the activities of the antioxidant enzymes (catalase, peroxidase, glutathione reductase and glutathione S-transferase) were determined after 24h (hours) of exposure to varying concentrations (0.025, 0.25, 2.5 and 25μg/L) of cylindrospermopsin. Responses with longer exposure periods (48, 96, 168h) were tested only with exposure to 2.5 and 25μg/L cylindrospermopsin. Additionally, the content of the carotenoids was determined as a possible non-enzymatic antioxidant defence mechanism against cylindrospermopsin. The levels of hydrogen peroxide increased after 24h even at the lowest cylindrospermopsin exposure concentrations. Catalase showed the most representative antioxidant response observed after 24h and maintained its activity throughout the experiment. Catalase activity corresponded with the contents of hydrogen peroxide at 2.5 and 25μg/L cylindrospermopsin. The data suggest that glutathione S-transferase, glutathione reductase and the carotenoid content act together with catalase but are more sensitive to higher concentrations of cylindrospermopsin and after a longer exposure period (168h). The results indicate that cylindrospermopsin promotes oxidative stress in L. minor at concentrations of 2.5 and 25μg/L. However, L. minor has sufficient defence mechanisms in place against this cyanobacterial toxin. Even though L. minor exhibits the potential to managing and control cylindrospermopsin contamination in aquatic systems, further studies in tolerance limits to

Effects of nutrient media on vegetative growth of Lemna minor and Landoltia punctata during in vitro and ex vitro cultivation

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Chokchai Kittiwongwattana

2013-01-01

Full Text Available Lemnaceous plants, namely Lemna minor and Landoltia punctata, have been used in various types of biological research. The effects of Murashige and Skoog (MS and Hoagland media on vegetative growth rate of both species during in vitro and ex vitro cultivation were investigated. Under axenic conditions, frond proliferation of L. minor and Lan. punctata in Hoagland medium are 8 and 11.5% respectively faster than that in MS medium. Biomass production in Hoagland medium also increases 2.2-fold (L. minor and 1.4-fold (Lan. punctata compared to MS medium. The roots of both species in MS medium are distinctly shorter than those in Hoagland medium. In contrast, ex vitro regeneration of frond colonies in MS medium is 22.2% (for L. minor and 17.1% (for Lan. punctata faster than in Hoagland medium. Similarly, ex vitro biomass production of both species in MS increases 1.8-fold (for L. minor and 1.3-fold (for Lan. punctata compared to that in Hoagland medium. Root elongation of the frond colonies in MS and Hoagland media is comparable. The distinct effects of MS and Hoagland media on vegetative growth of both species and the pre-determination of ex vitro growth rates in each medium are demonstrated.

Biological stress responses induced by alpha radiation exposure in Lemna minor

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Van Hoeck, A.; Horemans, N.; Van Hees, M.; Nauts, R. [Belgian Nuclear Research Centre SCK-CEN (Belgium); Knapen, D.; Blust, R. [University of Antwerp (Belgium)

2014-07-01

To enhance the robustness of radiation protection criteria for biota, additional information on the biological impact of radionuclides on non-human biota is needed. In particular the effects of alpha emitting isotopes have been poorly studied within a radioecological contextual though they exhibit a high linear energy transfer which can cause significant biological damage when taken up by organisms. Therefore, it is not only essential to measure alpha radiation toxicity, but also try to understand the underlying mechanisms of this stressor. The current study aimed to contribute to a better knowledge of the fundamental processes regulating alpha radiation stress response mechanisms in higher plants. {sup 241}Am was primarily selected as it is an almost pure alpha emitter and, as a daughter nuclide of {sup 241}Pu, it will become one of the dominant pollutants in plutonium affected areas. The aquatic macrophyte Lemna minor has proven its value in eco-toxicological research as representative of higher aquatic plants (OECD guideline nr. 221) and will be used to analyze alpha radiation stress in plant systems. An individual growth inhibition test was set up by means of single dose-response curve in order to identify the Effective Dose Rates (EDR-values) for frond size and biomass. As the mean path length is small for alpha particles, the accumulation of the radionuclide inside species represents almost exclusively the dosimetry. Therefore, quantification of {sup 241}Am uptake and {sup 241}Am distribution were evaluated separately for roots and fronds taking the activity concentrations of growth medium into account. Taken together with the respective dose conversion coefficients from the ERICA tool, this allowed to construct an accurate dosimetric model to determine internal and external dose rates. Different standard media were tested on growth rate and biomass to analyse the amount of {sup 241}Am taken up by the plants exposed from 2.5 to 100 kBq/L. From these

Lemna minor exposed to fluoranthene: growth, biochemical, physiological and histochemical changes.

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Zezulka, Stěpán; Kummerová, Marie; Babula, Petr; Váňová, Lucie

2013-09-15

Polycyclic aromatic hydrocarbons (PAHs) represent one of the major groups of organic contaminants in the aquatic environment. Duckweed (Lemna minor L.) is a common aquatic plant widely used in phytotoxicity tests for xenobiotic substances. The goal of this study was to assess the growth and the physiological, biochemical and histochemical changes in duckweed exposed for 4 and 10 days to fluoranthene (FLT, 0.1 and 1 mgL(-1)). Nonsignificant changes in number of plants, biomass production, leaf area size, content of chlorophylls a and b and carotenoids and parameters of chlorophyll fluorescence recorded after 4 and 10 days of exposure to FLT were in contrast with considerable changes at biochemical and histochemical levels. Higher occurrence of reactive oxygen species (ROS) caused by an exposure to FLT after 10 days as compared to control (hydrogen peroxide elevated by 13% in the 0.1 mgL(-1) and by 41% in the 1 mgL(-1) FLT; superoxide anion radical by 52% and 115% respectively) reflected in an increase in the activities of antioxidant enzymes (superoxide dismutase by 3% in both treatments, catalase by 9% and 1% respectively, ascorbate peroxidase by 21% and 5% respectively, guaiacol peroxidase by 12% in the 0.1 mgL(-1) FLT). Even the content of antioxidant compounds like ascorbate (by 20% in the 1 mgL(-1) FLT) or total thiols (reduced forms by 15% in the 0.1 mgL(-1) and 8% in the 1 mgL(-1) FLT, oxidized forms by 36% in the 0.1 mgL(-1) FLT) increased. Increased amount of ROS was followed by an increase in malondialdehyde content (by 33% in the 0.1 mgL(-1) and 79% in the 1 mgL(-1) FLT). Whereas in plants treated by the 0.1 mgL(-1) FLT the contents of total proteins and phenols increased by 15% and 25%, respectively, the 1 mgL(-1) FLT caused decrease of their contents by 32% and 7%. Microscopic observations of duckweed roots also confirmed the presence of ROS and related histochemical changes at the cellular and tissue levels. The assessment of phytotoxicity of organic

Application of Elovich equation on uptake kinetics of 137Cs by living freshwater macrophytes - a short duration laboratory study

International Nuclear Information System (INIS)

Jaison, T.J.; Patra, A.K.; Ravi, P.M.; Tripathi, R.M.

2014-01-01

Application of Elovich equation on uptake kinetics of 137 Cs by two living macrophytes during controlled experiments on short duration exposure is studied. Compliance to 2 nd order kinetics indicates the mechanism could be chemi-sorption, involving polar functional groups present on the extracelluar surface of the macrophytes. Data analysis suggests that Myriophyllum s. exhibits faster adsorption rate than Hydrilla v. As Myriophyllum s. exhibits better kinetics than Hydrilla v., former could be a better natural adsorbing media for 137 Cs. (author)

Removal of chromium ions from wastewater by duckweed, Lemna minor L. by using a pilot system with continuous flow.

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Uysal, Y

2013-12-15

The aim of this study was to determine the ability of Lemna minor to remove Cr (VI) ions from wastewater in a continuous flow pond system. This system was used to simulate a wastewater treatment pond and a natural wetland as habitat of plants. In order to find optimal conditions for chromium removal, ponds were operated with aqueous solutions having different pH (4.0-7.0) and chromium concentration of 0.25 mgCr(+6)/L, then plants were exposed to different chromium concentrations (0.25-5.0 mgCr(+6)/L) at pH 4.0. Chromium concentrations, both in biomass and wastewater, were measured and removal efficiency was determined throughout water flow. Growth factors such as growth rates, chlorophyll contents and dry/fresh weight ratios of plants were also determined to measure toxic effects of chromium. The percentages of chromium uptake (PMU) and bioconcentration factors (BCF) were calculated for each run. The highest accumulated chromium concentration (4.423 mgCr/g) was found in plants grown in the first chamber of pond operated at pH 4.0 and 5.0 mgCr/L, while the minimum accumulated chromium concentration (0.122 mgCr/g) was in plants grown in the last chamber of pond operated at pH 4.0 and 0.25 mgCr(+6)/L. Copyright © 2013 Elsevier B.V. All rights reserved.

Combined effects of elevated CO2 and Cd-contaminated water on growth, photosynthetic response, Cd accumulation and thiolic components status in Lemna minor L.

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Pietrini, F; Bianconi, D; Massacci, A; Iannelli, M A

2016-05-15

The objective of this study was to investigate the combined effects of elevated CO2 and cadmium (Cd) treatments on growth, photosynthetic efficiency and phytoremediation ability in Lemna minor L. Plants of L. minor were exposed to different Cd concentrations (0, 1.5, 2.5 and 5 mg L(-1) Cd) for periods of 24, 48 and 72 h at ambient (AC) and at elevated (EC) CO2 (350 and 700 ppm, respectively). Cadmium concentration, bioconcentration factor, enzyme activities and thiols content enhanced in plants with the increase of Cd treatments, time of exposure and at both CO2 levels. Glutathione levels increased only at AC. Growth, photosynthetic and chlorophyll fluorescence parameters, and the reduced glutathione to oxidized glutathione ratio declined in plants with increasing exposure time, Cd treatments and at both CO2 levels. Our results suggested that the alleviation of toxicity, at low Cd doses, observed in L. minor grown at EC is dependent on both increased photosynthesis and an enhanced antioxidant capacity. Copyright © 2016 Elsevier B.V. All rights reserved.

Duckweed (Lemna minor) as a Model Plant System for the Study of Human Microbial Pathogenesis

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Zhang, Yong; Hu, Yangbo; Yang, Baoyu; Ma, Fang; Lu, Pei; Li, Lamei; Wan, Chengsong; Rayner, Simon; Chen, Shiyun

2010-01-01

Background Plant infection models provide certain advantages over animal models in the study of pathogenesis. However, current plant models face some limitations, e.g., plant and pathogen cannot co-culture in a contained environment. Development of such a plant model is needed to better illustrate host-pathogen interactions. Methodology/Principal Findings We describe a novel model plant system for the study of human pathogenic bacterial infection on a large scale. This system was initiated by co-cultivation of axenic duckweed (Lemna minor) plants with pathogenic bacteria in 24-well polystyrene cell culture plate. Pathogenesis of bacteria to duckweed was demonstrated with Pseudomonas aeruginosa and Staphylococcus aureus as two model pathogens. P. aeruginosa PAO1 caused severe detriment to duckweed as judged from inhibition to frond multiplication and chlorophyll formation. Using a GFP-marked PAO1 strain, we demonstrated that bacteria colonized on both fronds and roots and formed biofilms. Virulence of PAO1 to duckweed was attenuated in its quorum sensing (QS) mutants and in recombinant strains overexpressing the QS quenching enzymes. RN4220, a virulent strain of S. aureus, caused severe toxicity to duckweed while an avirulent strain showed little effect. Using this system for antimicrobial chemical selection, green tea polyphenols exhibited inhibitory activity against S. aureus virulence. This system was further confirmed to be effective as a pathogenesis model using a number of pathogenic bacterial species. Conclusions/Significance Our results demonstrate that duckweed can be used as a fast, inexpensive and reproducible model plant system for the study of host-pathogen interactions, could serve as an alternative choice for the study of some virulence factors, and could also potentially be used in large-scale screening for the discovery of antimicrobial chemicals. PMID:21049039

Evaluation of environmental bacterial communities as a factor affecting the growth of duckweed Lemna minor.

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Ishizawa, Hidehiro; Kuroda, Masashi; Morikawa, Masaaki; Ike, Michihiko

2017-01-01

Duckweed (family Lemnaceae ) has recently been recognized as an ideal biomass feedstock for biofuel production due to its rapid growth and high starch content, which inspired interest in improving their productivity. Since microbes that co-exist with plants are known to have significant effects on their growth according to the previous studies for terrestrial plants, this study has attempted to understand the plant-microbial interactions of a duckweed, Lemna minor , focusing on the growth promotion/inhibition effects so as to assess the possibility of accelerated duckweed production by modifying co-existing bacterial community. Co-cultivation of aseptic L. minor and bacterial communities collected from various aquatic environments resulted in changes in duckweed growth ranging from -24 to +14% compared to aseptic control. A number of bacterial strains were isolated from both growth-promoting and growth-inhibitory communities, and examined for their co-existing effects on duckweed growth. Irrespective of the source, each strain showed promotive, inhibitory, or neutral effects when individually co-cultured with L. minor . To further analyze the interactions among these bacterial strains in a community, binary combinations of promotive and inhibitory strains were co-cultured with aseptic L. minor , resulting in that combinations of promotive-promotive or inhibitory-inhibitory strains generally showed effects similar to those of individual strains. However, combinations of promotive-inhibitory strains tended to show inhibitory effects while only Aquitalea magnusonii H3 exerted its plant growth-promoting effect in all combinations tested. Significant change in biomass production was observed when duckweed was co-cultivated with environmental bacterial communities. Promotive, neutral, and inhibitory bacteria in the community would synergistically determine the effects. The results indicate the possibility of improving duckweed biomass production via regulation of co

Duckweed (Lemna minor as a model plant system for the study of human microbial pathogenesis.

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Yong Zhang

Full Text Available BACKGROUND: Plant infection models provide certain advantages over animal models in the study of pathogenesis. However, current plant models face some limitations, e.g., plant and pathogen cannot co-culture in a contained environment. Development of such a plant model is needed to better illustrate host-pathogen interactions. METHODOLOGY/PRINCIPAL FINDINGS: We describe a novel model plant system for the study of human pathogenic bacterial infection on a large scale. This system was initiated by co-cultivation of axenic duckweed (Lemna minor plants with pathogenic bacteria in 24-well polystyrene cell culture plate. Pathogenesis of bacteria to duckweed was demonstrated with Pseudomonas aeruginosa and Staphylococcus aureus as two model pathogens. P. aeruginosa PAO1 caused severe detriment to duckweed as judged from inhibition to frond multiplication and chlorophyll formation. Using a GFP-marked PAO1 strain, we demonstrated that bacteria colonized on both fronds and roots and formed biofilms. Virulence of PAO1 to duckweed was attenuated in its quorum sensing (QS mutants and in recombinant strains overexpressing the QS quenching enzymes. RN4220, a virulent strain of S. aureus, caused severe toxicity to duckweed while an avirulent strain showed little effect. Using this system for antimicrobial chemical selection, green tea polyphenols exhibited inhibitory activity against S. aureus virulence. This system was further confirmed to be effective as a pathogenesis model using a number of pathogenic bacterial species. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that duckweed can be used as a fast, inexpensive and reproducible model plant system for the study of host-pathogen interactions, could serve as an alternative choice for the study of some virulence factors, and could also potentially be used in large-scale screening for the discovery of antimicrobial chemicals.

Accumulation of {sup 99}Tc in duckweed Lemna minor L. as a function of growth rate and {sup 99}Tc concentration

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Hattink, J. E-mail: jhattink@hotmail.com; Wolterbeek, H.Th

2001-07-01

This study focuses on the question of whether short-term studies can be used to forecast the accumulation of the long-lived fission product {sup 99}Tc in duckweed, Lemna minor L., grown in the field; in other words, are the accumulation parameters independent of changing growth rates typical of natural populations of duckweed. Two processes determine the {sup 99}Tc accumulation: (i) uptake and release of {sup 99}TcO{sub 4}{sup -}, characterised by a concentration factor, K{sub d}, and (ii) first-order reduction and complexation of Tc{sup VII}, characterised by k{sub red}. At various {sup 99}Tc concentrations, the growth, total Tc and TcO{sub 4}{sup -} accumulation were monitored over 10 days; parameters were fitted and compared with earlier results. Both K{sub d} and k{sub red} turn out to be independent of time, concentration and growth rate up to a concentration of 10{sup -6} mol l{sup -1} {sup 99}TcO{sub 4}{sup -}. Concentrations above this level result in toxic effects. The Tc accumulation in field populations of duckweed at Tc concentrations which generally occur in the environment can be forecasted by using the results from short-term experiments.

Wood ash residue causes a mixture of growth promotion and toxicity in Lemna minor.

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Jagodzinski, Lucas S; O'Donoghue, Marian T; Heffernan, Liam B; van Pelt, Frank N A M; O'Halloran, John; Jansen, Marcel A K

2018-06-01

The use of wood as a sustainable biofuel results in the generation of residual wood ash. The ash contains high amounts of plant macronutrients such as phosphorus, potassium, calcium as well as several micronutrients. To explore the potential use of wood ash as a fertiliser, the growth enhancing properties of Sitka spruce (Picea sitchensis Bong.) wood ash were contrasted with the potential toxic action, using common duckweed (Lemna minor L.) as a model test species. The growth of L. minor exposed to wood bottom and fly ash solids and corresponding leachates was assessed in ultra-oligotrophic and eutrophic media. Ash solids and leachates were also tested as neutralized preparations. Suspended ash solids promoted L. minor growth up to concentrations of 2.5-5g/L. Leachates promoted growth up to 10g ash equivalents per litre, but for bottom ash only. Beneficial effects of wood ash were most pronounced on ultra-oligotrophic medium. However, on such nutrient-deficient medium severe inhibition of L. minor biomass and frond growth was observed at relatively low concentrations of fly ash (EC 50 =14g/L). On standard, eutrophic medium, higher concentrations of fly ash (EC 50 =21g/L), or neutralized fly ash (EC 50 =37g/L) were required to impede growth. Bottom ash, or neutralized bottom ash retarded growth at concentrations of 51g/L and 74g/L (EC 50 ), respectively, in eutrophic medium. It appears that phytotoxicity is due to the elemental composition of the ash, its alkaline character, and possible interactions between these two properties. Growth promotion was due to the substantial content of plant nutrients. This study underlines the importance of the receiving environment (nutrient status and pH) in determining the balance between toxicity and growth promotion, and shows that the margin between growth promoting and toxicity inducing concentrations can be enlarged through ash neutralization. Copyright © 2017 Elsevier B.V. All rights reserved.

Transcriptomic and physiological analysis of common duckweed Lemna minor responses to NH4(+) toxicity.

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Wang, Wenguo; Li, Rui; Zhu, Qili; Tang, Xiaoyu; Zhao, Qi

2016-04-18

Plants can suffer ammonium (NH4 (+)) toxicity, particularly when NH4 (+) is supplied as the sole nitrogen source. However, our knowledge about the underlying mechanisms of NH4 (+) toxicity is still largely unknown. Lemna minor, a model duckweed species, can grow well in high NH4 (+) environment but to some extent can also suffer toxic effects. The transcriptomic and physiological analysis of L. minor responding to high NH4 (+) may provide us some interesting and useful information not only in toxic processes, but also in tolerance mechanisms. The L. minor cultured in the Hoagland solution were used as the control (NC), and in two NH4 (+) concentrations (NH4 (+) was the sole nitrogen source), 84 mg/L (A84) and 840 mg/L (A840) were used as stress treatments. The NH4 (+) toxicity could inhibit the growth of L. minor. Reactive oxygen species (ROS) and cell death were studied using stained fronds under toxic levels of NH4 (+). The malondialdehyde content and the activities of superoxide dismutase and peroxidase increased from NC to A840, rather than catalase and ascorbate peroxidase. A total of 6.62G nucleotides were generated from the three distinct libraries. A total of 14,207 differentially expressed genes (DEGs) among 70,728 unigenes were obtained. All the DEGs could be clustered into 7 profiles. Most DEGs were down-regulated under NH4 (+) toxicity. The genes required for lignin biosynthesis in phenylpropanoid biosynthesis pathway were up-regulated. ROS oxidative-related genes and programmed cell death (PCD)-related genes were also analyzed and indicated oxidative damage and PCD occurring under NH4 (+) toxicity. The first large transcriptome study in L. minor responses to NH4 (+) toxicity was reported in this work. NH4 (+) toxicity could induce ROS accumulation that causes oxidative damage and thus induce cell death in L. minor. The antioxidant enzyme system was activated under NH4 (+) toxicity for ROS scavenging. The phenylpropanoid pathway was stimulated under

Phytoremediation applications in natural condition and in mesocosm: The uptake of cadmium by Lemna minuta Kunth, a non-native species in Italian watercourses.

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Chiudioni, Filippo; Trabace, Teresa; Di Gennaro, Spartaco; Palma, Achille; Manes, Fausto; Mancini, Laura

2017-04-03

Metal pollution in water and soil is an environmental and public health issue. Cadmium (Cd) is included in the list of priority hazardous substances in the European Water Framework Directive. Phytoremediation system is a cost-effective, plant-based approach that takes advantage of the ability of plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues. We studied the presence and the importance of an invasive species, such as Lemna minuta, in the environment and the effects of Cd pollution on this species. Growth, removal, and tolerance were evaluated for different Cd concentrations and different times of plant exposure. Overall, the results show that L. minuta has a good capacity of growth, metal bioconcentration, and tolerance up to 3 days of exposure at 0.5 and 1.5 mg L -1 of Cd. In particular, L. minuta was able to accumulate Cd up to 3771 mg kg -1 on dry mass basis. We can conclude that L. minuta possesses a great capability of Cd absorption and accumulation, thus supporting a potential use of this species in designing a metal bioremediation system in phytoremediation field.

β-Radiation Stress Responses on Growth and Antioxidative Defense System in Plants: A Study with Strontium-90 in Lemna minor

Directory of Open Access Journals (Sweden)

Arne Van Hoeck

2015-07-01

Full Text Available In the following study, dose dependent effects on growth and oxidative stress induced by β-radiation were examined to gain better insights in the mode of action of β-radiation induced stress in plant species. Radiostrontium (90Sr was used to test for β-radiation induced responses in the freshwater macrophyte Lemna minor. The accumulation pattern of 90Sr was examined for L. minor root and fronds separately over a seven-day time period and was subsequently used in a dynamic dosimetric model to calculate β-radiation dose rates. Exposing L. minor plants for seven days to a 90Sr activity concentration of 25 up to 25,000 kBq·L−1 resulted in a dose rate between 0.084 ± 0.004 and 97 ± 8 mGy·h−1. After seven days of exposure, root fresh weight showed a dose dependent decrease starting from a dose rate of 9.4 ± 0.5 mGy·h−1. Based on these data, an EDR10 value of 1.5 ± 0.4 mGy·h−1 was estimated for root fresh weight and 52 ± 17 mGy·h−1 for frond fresh weight. Different antioxidative enzymes and metabolites were further examined to analyze if β-radiation induces oxidative stress in L. minor.

Linking mode of action of the model respiratory and photosynthesis uncoupler 3,5-dichlorophenol to adverse outcomes in Lemna minor.

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Xie, Li; Gomes, Tânia; Solhaug, Knut Asbjørn; Song, You; Tollefsen, Knut Erik

2018-04-01

Standard chemical toxicity testing guidelines using aquatic plant Lemna minor have been developed by several international standardisation organisations. Although being highly useful for regulatory purposes by focusing on traditional adverse endpoints, these tests provide limited information about the toxic mechanisms and modes of action (MoA). The present study aimed to use selected functional assays in L. minor after exposure to 3,5-dichlorophenol (3,5-DCP) as a model to characterise the toxic mechanisms causing growth inhibition and lethality in primary producers. The results demonstrated that 3,5-DCP caused concentration-dependent effects in chloroplasts and mitochondria. Uncoupling of oxidative phosphorylation (OXPHOS), reduction in chlorophyll (Chlorophyll a and b) content, reproduction rate and frond size were the most sensitive endpoints, followed by formation of reactive oxygen species (ROS), lipid peroxidation (LPO), reduction of carotenoid content and impairment of photosynthesis efficiency. Suppression of photosystem II (PSII) efficiency, electron transport rate (ETR), chlorophyll (a and b) contents and oxidative phosphorylation (OXPHOS) were closely correlated while ROS production and LPO were negative correlated with ETR, carotenoid content and growth parameters. A network of conceptual Adverse Outcome Pathways (AOPs) was developed to decipher the causal relationships between molecular, cellular, and apical adverse effects occurring in L. minor to form a basis for future studies with similar compounds. Copyright © 2018 Elsevier B.V. All rights reserved.

β-Radiation Stress Responses on Growth and Antioxidative Defense System in Plants: A Study with Strontium-90 in Lemna minor.

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Van Hoeck, Arne; Horemans, Nele; Van Hees, May; Nauts, Robin; Knapen, Dries; Vandenhove, Hildegarde; Blust, Ronny

2015-07-07

In the following study, dose dependent effects on growth and oxidative stress induced by β-radiation were examined to gain better insights in the mode of action of β-radiation induced stress in plant species. Radiostrontium (⁹⁰Sr) was used to test for β-radiation induced responses in the freshwater macrophyte Lemna minor. The accumulation pattern of 90Sr was examined for L. minor root and fronds separately over a seven-day time period and was subsequently used in a dynamic dosimetric model to calculate β-radiation dose rates. Exposing L. minor plants for seven days to a ⁹⁰Sr activity concentration of 25 up to 25,000 kBq·L⁻¹ resulted in a dose rate between 0.084 ± 0.004 and 97 ± 8 mGy·h⁻¹. After seven days of exposure, root fresh weight showed a dose dependent decrease starting from a dose rate of 9.4 ± 0.5 mGy·h⁻¹. Based on these data, an EDR10 value of 1.5 ± 0.4 mGy·h⁻¹ was estimated for root fresh weight and 52 ± 17 mGy·h⁻¹ for frond fresh weight. Different antioxidative enzymes and metabolites were further examined to analyze if β-radiation induces oxidative stress in L. minor.

Trophic transfer of Cd from duckweed (Lemna minor L.) to tilapia (Oreochromis mossambicus).

Science.gov (United States)

Xue, Yan; Peijnenburg, Willie J G M; Huang, Jin; Wang, Dengjun; Jin, Yan

2018-05-01

The transfer of the toxic heavy metal Cd from duckweed (Lemna minor L.) to the freshwater fish tilapia (Oreochromis mossambicus) was investigated. Concentrations of Cd in different chemical forms in duckweed and in different tissues (gut, edible muscle, and remnants or residual) of tilapia (i.e., ethanol-extractable fraction [F E ], HCl-extractable fraction [F HCl ], and residual fraction [F R ]) were quantified, and the bioaccumulation factors (BAFs) of Cd in the tilapia body were calculated. Simple linear regression analysis was used to unravel the correlation and accumulation mechanisms of Cd along the short food chain. Our results showed that with increasing exposure concentrations of Cd (0-50 μM for duckweed and 0-10 μM for tilapia), the total, F E (F e,d )-, F HCl (F h,d )-, and F R (F r,d )-Cd concentrations in duckweed and different tissues of tilapia increased progressively. The Cd sources (aqueous or dietary) influenced the BAF for Cd accumulation in the whole body of tilapia. Furthermore, regression analyses yielded significant positive correlations (R 2 > 0.96) between the Cd concentration in duckweed and in both the 3 parts and the whole body of tilapia. This finding suggests that Cd transfer from duckweed to tilapia can be quantitatively evaluated when tilapia is exposed only to duckweed. In addition, the linear regression between Cd accumulation in whole tilapia and F e,d -, F h,d -, and F r,d -Cd showed that particularly the correlation with F e,d -Cd is statistically significant (p < 0.001). The accumulated Cd concentrations and chemical forms in tilapia tissues also positively correlated with Cd sources (solution or duckweed). Compared with waterborne exposure only, duckweed especially increased the accumulation of Cd in the gut of tilapia. Taken together, our findings support a strong dependence of Cd accumulation and transfer from duckweed to tilapia on its chemical forms, especially on F e,d -Cd. This knowledge may expedite more

Gas chromatography-mass spectrometry of N-heptafluorobutyryl isobutyl esters of amino acids in the analysis of the kinetics of [15N]H4+ assimilation in Lemna minor L

International Nuclear Information System (INIS)

Rhodes, D.; Myers, A.C.; Jamieson, G.

1981-01-01

Rapid, sensitive, and selective methods for the determination of the 15 N abundance of amino acids in isotopic tracer experiments with plant tissues are described and discussed. Methodology has been directly tested in an analysis of the kinetics of [ 15 N]H 4 + assimilation in Lemna minor L. The techniques utilize gas chromatography-mass spectrometry selected ion monitoring of major fragments containing the N moiety of N-heptafluorobutyryl isobutyl esters of amino acids. The ratio of selected ion pairs at the characteristic retention time of each amino acid derivative can be used to calcuulate 15 N abundance with an accuracy of +/- 1 atom % excess 15 N using samples containing as little as 30 picomoles of individual amino acids. Up to 11 individual amino acid derivatives can be selectively monitored in a single chromatogram of 30 minutes. It is suggested that these techniques will be useful in situations where the small quantities of N available for analysis have hitherto hindered the use of 15 N-labeled precursors

Ecotoxicological evaluation of propranolol hydrochloride and losartan potassium to Lemna minor L. (1753) individually and in binary mixtures.

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Godoy, Aline A; Kummrow, Fábio; Pamplin, Paulo Augusto Z

2015-07-01

Antihypertensive pharmaceuticals, including the beta-blockers, are one of the most detected therapeutic classes in the environment. The ecotoxicity of propranolol hydrochloride and losartan potassium was evaluated, both individually and combined in a binary mixture, by using the Lemna minor growth inhibition test. The endpoints evaluated in the single-pharmaceutical tests were frond number, total frond area and fresh weight. For the evaluation of the mixture toxicity, the selected endpoint was frond number. Water quality criteria values (WQC) were derived for the protection of freshwater and saltwater pelagic communities regarding the effects induced by propranolol and losartan using ecotoxicological data from the literature, including our data. The risks associated with both pharmaceutical effects on non-target organisms were quantified through the measured environmental concentration (MEC)/predicted-no-effect concentration (PNEC) ratios. For propranolol, the total frond area was the most sensitive endpoint (EC50 = 77.3 mg L(-1)), while for losartan there was no statistically significant difference between the endpoints. Losartan is only slightly more toxic than propranolol. Both concentration addition and independent action models overestimated the mixture toxicity of the pharmaceuticals at all the effect concentration levels evaluated. The joint action of both pharmaceuticals showed an antagonistic interaction to L. minor. Derived WQC assumed lower values for propranolol than for losartan. The MEC/PNEC ratios showed that propranolol may pose a risk for the most sensitive aquatic species, while acceptable risks posed by losartan were estimated for most of aquatic matrices. To the authors knowledge these are the first data about losartan toxicity for L. minor.

Root length of aquatic plant, Lemna minor L., as an optimal toxicity endpoint for biomonitoring of mining effluents.

Science.gov (United States)

Gopalapillai, Yamini; Vigneault, Bernard; Hale, Beverley A

2014-10-01

Lemna minor, a free-floating macrophyte, is used for biomonitoring of mine effluent quality under the Metal Mining Effluent Regulations (MMER) of the Environmental Effects Monitoring (EEM) program in Canada and is known to be sensitive to trace metals commonly discharged in mine effluents such as Ni. Environment Canada's standard toxicity testing protocol recommends frond count (FC) and dry weight (DW) as the 2 required toxicity endpoints-this is similar to other major protocols such as those by the US Environmental Protection Agency (USEPA) and the Organisation for Economic Co-operation and Development (OECD)-that both require frond growth or biomass endpoints. However, we suggest that similar to terrestrial plants, average root length (RL) of aquatic plants will be an optimal and relevant endpoint. As expected, results demonstrate that RL is the ideal endpoint based on the 3 criteria: accuracy (i.e., toxicological sensitivity to contaminant), precision (i.e., lowest variance), and ecological relevance (metal mining effluents). Roots are known to play a major role in nutrient uptake in conditions of low nutrient conditions-thus having ecological relevance to freshwater from mining regions. Root length was the most sensitive and precise endpoint in this study where water chemistry varied greatly (pH and varying concentrations of Ca, Mg, Na, K, dissolved organic carbon, and an anthropogenic organic contaminant, sodium isopropyl xanthates) to match mining effluent ranges. Although frond count was a close second, dry weight proved to be an unreliable endpoint. We conclude that toxicity testing for the floating macrophyte should require average RL measurement as a primary endpoint. © 2014 SETAC.

Isolation of Vibrio cholera El Tor Inaba From Lemna minor and Eichhornia crassipens Roots in Veracruz, Mexico

Science.gov (United States)

Cordoba Aguilar, Edgar; Herrera Rivero, Marisol; Rubi, Alberto; Arroyo-Helguera, Omar; Coutino Rodriguez, Rocio

2014-01-01

Background: During epidemic periods, the strain Vibrio cholera El Tor has been isolated from the aquatic macrophyte roots of Eichhornia crassipens and Lemna minor, suggesting that aquatic plants could be environmental reservoirs through either a non-specific association or a commensalism relationship. Therefore, it is important to understand V. cholera reservoirs in order to establish prevention strategies against this pathogen. Objectives: Our interest was to determine whether V. cholera could be isolated and typified from L. minor and E. crassipens roots. Materials and Methods: From 2004 to 2005, plants were collected from various ecological niches and the roots were used to isolate V. cholera. Standard bacteriological, biochemical and serological tests were used for its typification. Results: In five out of the nine ecological niches explored, we collected either L. minor or E. crassipens, as these specimens cohabited only in two niches. V. cholera was isolated from both L. minor and E. crassipens roots. The isolated V. cholera showed the same biochemical characteristics as the pure V. cholera strain which was used as a control. The isolated V. cholera corresponded to V. cholera O1 El Tor Inaba, which is the same serotype related to the last outbreak in Mexico. Conclusions: For first time V. cholera El Tor Inaba has been isolated several years after the last emergence of cholera in Mexico. A viable and cultivable V. cholera strain, sourced from freshwater niches in E. crassipens and L. minor roots, suggests the importance of these plants as a permanent aquatic reservoir for these organisms. The monitoring of E. crassipens and L. minor is the responsibility of health institutions in order to evaluate the ongoing risks. PMID:25147681

Effects of treated industrial wastewaters and temperatures on growth and enzymatic activities of duckweed (Lemna minor L.).

Science.gov (United States)

Basiglini, E; Pintore, M; Forni, C

2018-05-30

The efficacy of the removal of contaminants from wastewater depends on physico-chemical properties of pollutants and the efficiency of treatment plant. Sometimes, low amounts of toxic compounds can be still present in the treated sewage. In this work we considered the effects of contaminant residues in treated wastewaters and of temperatures on Lemna minor L. Treated effluent waters were collected, analyzed and used as duckweed growth medium. In order to better understand the effects of micropollutants and seasonal variation, the plants were grown under ambient conditions for seven days in summer and winter. Relative growth rate, pigments and phenolic compounds concentrations were determined, as well as the activities of catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (G-POD) and polyphenol oxidase (PPO). The pollutant concentrations varied in the two seasons, depending on the industrial and municipal activities and efficiency of treatments. Treated waters contained heavy metals, nitrogenous and phosphorus compounds, surfactants and hydrocarbons. Compared to the control, duckweed growth of treated plants decreased by 25% in summer, while in the winter due to the lower temperatures and the presence of pollutants was completely impeded. The amounts of photosynthetic pigments of treated plants were not significantly affected in the summer, while they were higher than the control in the winter when the effluent had a high nitrogen amount. High CAT activity was registered in both seasons. Treated plants had significantly lower APX activity in the summer (53%) and winter (59%) respect to the controls. The observed inhibition of the peroxidase activities in the exposed plants, confirms the controversy existing in the literature about the variability of enzymatic response in stress condition. Copyright © 2018 Elsevier Inc. All rights reserved.

Isolation of Vibrio cholera El Tor Inaba From Lemna minor and Eichhornia crassipens Roots in Veracruz, Mexico.

Science.gov (United States)

Cordoba Aguilar, Edgar; Herrera Rivero, Marisol; Rubi, Alberto; Arroyo-Helguera, Omar; Coutino Rodriguez, Rocio

2014-03-01

During epidemic periods, the strain Vibrio cholera El Tor has been isolated from the aquatic macrophyte roots of Eichhornia crassipens and Lemna minor, suggesting that aquatic plants could be environmental reservoirs through either a non-specific association or a commensalism relationship. Therefore, it is important to understand V. cholera reservoirs in order to establish prevention strategies against this pathogen. Our interest was to determine whether V. cholera could be isolated and typified from L. minor and E. crassipens roots. From 2004 to 2005, plants were collected from various ecological niches and the roots were used to isolate V. cholera. Standard bacteriological, biochemical and serological tests were used for its typification. In five out of the nine ecological niches explored, we collected either L. minor or E. crassipens, as these specimens cohabited only in two niches. V. cholera was isolated from both L. minor and E. crassipens roots. The isolated V. cholera showed the same biochemical characteristics as the pure V. cholera strain which was used as a control. The isolated V. cholera corresponded to V. cholera O1 El Tor Inaba, which is the same serotype related to the last outbreak in Mexico. For first time V. cholera El Tor Inaba has been isolated several years after the last emergence of cholera in Mexico. A viable and cultivable V. cholera strain, sourced from freshwater niches in E. crassipens and L. minor roots, suggests the importance of these plants as a permanent aquatic reservoir for these organisms. The monitoring of E. crassipens and L. minor is the responsibility of health institutions in order to evaluate the ongoing risks.

Comparison of gamma- and beta radiation stress responses on anti-oxidative defense system and DNA modifications in Lemna minor

Energy Technology Data Exchange (ETDEWEB)

Van Hoeck, Arne [SCK.CEN, Boeretang 200 2400 Mol (Belgium); University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen (Belgium); Horemans, Nele; Van Hees, May; Nauts, Robin; Vandenhove, Hildegarde [SCK.CEN, Boeretang 200 2400 Mol (Belgium); Knapen, Dries; Blust, Ronny [University of Antwerp, Groenenborgerlaan 171, 2020 Antwerpen (Belgium)

2014-07-01

The biological effects and interactions of different radiation types in plants are still far from understood. Additional knowledge on the impact of various kinds of ionizing radiation in plants on individual, biochemical and molecular level is needed to unravel and compare the toxic mode of action. Among different radiation types, external gamma radiation treatments have been mostly studied both in lab and field studies to derive the biological impact of radiation toxicity in organisms. However, environmental relevant studies on chronic low-dose gamma exposures are scarce. The radio-ecologically relevant radionuclide {sup 90}Sr is a pure beta emitting isotope and originates from nuclear activities and accidents. Although this radionuclide is not essential for plant metabolism, it bears a chemical analogy with the essential plant macro-nutrient Ca{sup 2+} thereby taking advantage of Ca{sup 2+} transport systems to contaminate plant organs and tissues. Ones plants are exposed to radiation stress, ionization events can cause an increase in reactive oxygen species (ROS) and can induce damage to biological material like DNA, lipids and structural proteins. The following work aimed at evaluating individual, biochemical and molecular endpoints to understand and to compare the mode of action of gamma- and beta radiation stress in plants. Having an equal relative biological effectiveness to non-human biota, it is still not clear in how plants differ or overlap in sensing and interpreting highly penetrating electromagnetic radiation with short-range particle radiation. The floating plant Lemna minor was chosen as model system. Following the OECD guidelines Lemna plants were being exposed separately to an external gamma radiation source or to a {sup 90}Sr-contaminated growth medium to obtain single-dose response curves for each type of radiation. In order to acquire accurate dose rate quantifications for beta radiation exposures, {sup 90}Sr uptake and accumulation of root and

Phytotechnology Technical and Regulatory Guidance and Decision Trees, Revised

Science.gov (United States)

2009-02-01

Anderson, Guthrie, and Walton 1993 Demeton-8- methyl Duckweed ( Lemna minor ) PE, PD Approximately 10% total transformation (PE and PD) measured in 48...Duckweed ( Lemna minor ) PE, PD Approximately 25% total transformation (PE and PD) measured in 24 hours Gao et al. 1998 Malathion Parrot feather...in 14 days Anderson, Kruger, and Coats 1994 Metolachor Duckweed ( Lemna minor ) PE 25% remaining in the water after 16 days Rice, Anderson, and

Comparative investigation of toxicity and bioaccumulation of Cd-based quantum dots and Cd salt in freshwater plant Lemna minor L.

Science.gov (United States)

Modlitbová, Pavlína; Novotný, Karel; Pořízka, Pavel; Klus, Jakub; Lubal, Přemysl; Zlámalová-Gargošová, Helena; Kaiser, Jozef

2018-01-01

The purpose of this study was to determine the toxicity of two different sources of cadmium, i.e. CdCl 2 and Cd-based Quantum Dots (QDs), for freshwater model plant Lemna minor L. Cadmium telluride QDs were capped with two coating ligands: glutathione (GSH) or 3-mercaptopropionic acid (MPA). Growth rate inhibition and final biomass inhibition of L. minor after 168-h exposure were monitored as toxicity endpoints. Dose-response curves for Cd toxicity and EC50 168h values were statistically evaluated for all sources of Cd to uncover possible differences among the toxicities of tested compounds. Total Cd content and its bioaccumulation factors (BAFs) in L. minor after the exposure period were also determined to distinguish Cd bioaccumulation patterns with respect to different test compounds. Laser-Induced Breakdown Spectroscopy (LIBS) with lateral resolution of 200µm was employed in order to obtain two-dimensional maps of Cd spatial distribution in L. minor fronds. Our results show that GSH- and MPA-capped Cd-based QDs have similar toxicity for L. minor, but are significantly less toxic than CdCl 2 . However, both sources of Cd lead to similar patterns of Cd bioaccumulation and distribution in L. minor fronds. Our results are in line with previous reports that the main mediators of Cd toxicity and bioaccumulation in aquatic plants are Cd 2+ ions dissolved from Cd-based QDs. Copyright © 2017 Elsevier Inc. All rights reserved.

Microbial Detoxification of Deoxynivalenol (DON), Assessed via a Lemna minor L. Bioassay, through Biotransformation to 3-epi-DON and 3-epi-DOM-1.

Science.gov (United States)

Vanhoutte, Ilse; De Mets, Laura; De Boevre, Marthe; Uka, Valdet; Di Mavungu, José Diana; De Saeger, Sarah; De Gelder, Leen; Audenaert, Kris

2017-02-13

Mycotoxins are toxic metabolites produced by fungi. To mitigate mycotoxins in food or feed, biotransformation is an emerging technology in which microorganisms degrade toxins into non-toxic metabolites. To monitor deoxynivalenol (DON) biotransformation, analytical tools such as ELISA and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) are typically used. However, these techniques do not give a decisive answer about the remaining toxicity of possible biotransformation products. Hence, a bioassay using Lemna minor L. was developed. A dose-response analysis revealed significant inhibition in the growth of L. minor exposed to DON concentrations of 0.25 mg/L and higher. Concentrations above 1 mg/L were lethal for the plant. This bioassay is far more sensitive than previously described systems. The bioassay was implemented to screen microbial enrichment cultures, originating from rumen fluid, soil, digestate and activated sludge, on their biotransformation and detoxification capability of DON. The enrichment cultures originating from soil and activated sludge were capable of detoxifying and degrading 5 and 50 mg/L DON. In addition, the metabolites 3-epi-DON and the epimer of de-epoxy-DON (3-epi-DOM-1) were found as biotransformation products of both consortia. Our work provides a new valuable tool to screen microbial cultures for their detoxification capacity.

Microbial Detoxification of Deoxynivalenol (DON, Assessed via a Lemna minor L. Bioassay, through Biotransformation to 3-epi-DON and 3-epi-DOM-1

Directory of Open Access Journals (Sweden)

Ilse Vanhoutte

2017-02-01

Full Text Available Mycotoxins are toxic metabolites produced by fungi. To mitigate mycotoxins in food or feed, biotransformation is an emerging technology in which microorganisms degrade toxins into non-toxic metabolites. To monitor deoxynivalenol (DON biotransformation, analytical tools such as ELISA and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS are typically used. However, these techniques do not give a decisive answer about the remaining toxicity of possible biotransformation products. Hence, a bioassay using Lemna minor L. was developed. A dose–response analysis revealed significant inhibition in the growth of L. minor exposed to DON concentrations of 0.25 mg/L and higher. Concentrations above 1 mg/L were lethal for the plant. This bioassay is far more sensitive than previously described systems. The bioassay was implemented to screen microbial enrichment cultures, originating from rumen fluid, soil, digestate and activated sludge, on their biotransformation and detoxification capability of DON. The enrichment cultures originating from soil and activated sludge were capable of detoxifying and degrading 5 and 50 mg/L DON. In addition, the metabolites 3-epi-DON and the epimer of de-epoxy-DON (3-epi-DOM-1 were found as biotransformation products of both consortia. Our work provides a new valuable tool to screen microbial cultures for their detoxification capacity.

Getting More Ecologically Relevant Information from Laboratory Tests: Recovery of Lemna minor After Exposure to Herbicides and Their Mixtures.

Science.gov (United States)

Knežević, Varja; Tunić, Tanja; Gajić, Pero; Marjan, Patricija; Savić, Danko; Tenji, Dina; Teodorović, Ivana

2016-11-01

Recovery after exposure to herbicides-atrazine, isoproturon, and trifluralin-their binary and ternary mixtures, was studied under laboratory conditions using a slightly adapted standard protocol for Lemna minor. The objectives of the present study were (1) to compare empirical to predicted toxicity of selected herbicide mixtures; (2) to assess L. minor recovery potential after exposure to selected individual herbicides and their mixtures; and (3) to suggest an appropriate recovery potential assessment approach and endpoint in a modified laboratory growth inhibition test. The deviation of empirical from predicted toxicity was highest in binary mixtures of dissimilarly acting herbicides. The concentration addition model slightly underestimated mixture effects, indicating potential synergistic interactions between photosynthetic inhibitors (atrazine and isoproturon) and a cell mitosis inhibitor (trifluralin). Recovery after exposure to the binary mixture of atrazine and isoproturon was fast and concentration-independent: no significant differences between relative growth rates (RGRs) in any of the mixtures (IC10 Mix , 25 Mix , and 50 Mix ) versus control level were recorded in the last interval of the recovery phase. The recovery of the plants exposed to binary and ternary mixtures of dissimilarly acting herbicides was strictly concentration-dependent. Only plants exposed to IC10 Mix , regardless of the herbicides, recovered RGRs close to control level in the last interval of the recovery phase. The inhibition of the RGRs in the last interval of the recovery phase compared with the control level is a proposed endpoint that could inform on reversibility of the effects and indicate possible mixture effects on plant population recovery potential.

A full evaluation for the enantiomeric impacts of lactofen and its metabolites on aquatic macrophyte Lemna minor.

Science.gov (United States)

Wang, Fang; Liu, Donghui; Qu, Han; Chen, Li; Zhou, Zhiqiang; Wang, Peng

2016-09-15

Pesticide pollution of surface water represents a considerable danger for the aquatic plants which play very crucial roles in aquatic system such as oxygen production, nutrient cycling, water quality controlling and sediment stabilization. In this work, the toxic effects of the chiral herbicide lactofen and its three metabolites (desethyl lactofen, acifluorfene and amino acifluorfene) to the aquatic plant Lemna minor (L. minor) on enantiomeric level were evaluated. The influences on growth rate, fresh weight, content of photosynthetic pigment, protein and malondialdehyde (MDA) and the activities of antioxidant defense enzymes (catalase (CAT) and superoxide dismutase (SOD)) were measured after 7 days of exposure. L. minor growth was inhibited in the order of (S)-desethyl lactofen > racemic-desethyl lactofen > (R)-desethyl lactofen > racemic-lactofen > (S)-lactofen > (R)-lactofen > acifluorfene > amino acifluorfene, and the IC50 (7d) values showed desethyl lactofen was the most powerful compound which was about twice as toxic as lactofen. The contents of chlorophylls (Chl) and carotenoids (Car) were significantly reduced by the chemicals, while, the levels of protein, MDA and the activity of CAT and SOD enzymes increased in most cases. The obtained results revealed that lactofen and its metabolites had an undesirable effect on L. minor, in terms of physiological and biochemical aspects. Besides, enantioselective toxicity of lactofen and desethyl lactofen to L. minor was observed. The S-enantiomer of desethyl lactofen was more toxic than the corresponding R-enantiomer. Furthermore, racemic lactofen was more toxic than the individual enantiomers. The side effects of pesticide metabolites and the enantioselectivity should be considered in developing optically pure products and risk assessment. Copyright © 2016 Elsevier Ltd. All rights reserved.

浮萍饲喂黄粉虫的效益分析%Effects and profits of feeding Tenebrio molitor with Lemna minor

Institute of Scientific and Technical Information of China (English)

郑燕玲; 赖锦洪; 杨靖; 谢思; 羊海军

2015-01-01

以传统饲料配方为对照,测试添加不同用量浮萍(Lemna minor)对黄粉虫(Tenebrio molitor)幼虫生长发育及蛋白、粗脂肪含量等指标的影响.结果表明,黄粉虫幼虫对新鲜浮萍适口性良好;新鲜浮萍投饲比例大于80％,对黄粉虫幼虫的生长发育有阻滞,但对其蛋白、粗脂肪含量无显著影响(P＞0.05);以鲜浮萍∶麦麸质量百分比为65％∶35％配置,可使饲料成本降低33.95％,且不影响黄粉虫的饲喂周期、产量和质量.利用新鲜浮萍饲喂黄粉虫幼虫是可行的,通过构建“浮萍-黄粉虫”食物链,可显著降低养殖成本,增加经济效益和生态效益,促进黄粉虫养殖行业发展.

Lemna minor plants chronically exposed to ionising radiation: RNA-seq analysis indicates a dose rate dependent shift from acclimation to survival strategies.

Science.gov (United States)

Van Hoeck, Arne; Horemans, Nele; Nauts, Robin; Van Hees, May; Vandenhove, Hildegarde; Blust, Ronny

2017-04-01

Ecotoxicological research provides knowledge on ionising radiation-induced responses in different plant species. However, the sparse data currently available are mainly extracted from acute exposure treatments. To provide a better understanding of environmental exposure scenarios, the response to stress in plants must be followed in more natural relevant chronic conditions. We previously showed morphological and biochemical responses in Lemna minor plants continuously exposed for 7days in a dose-rate dependent manner. In this study responses on molecular (gene expression) and physiological (photosynthetic) level are evaluated in L. minor plants exposed to ionising radiation. To enable this, we examined the gene expression profiles of irradiated L. minor plants by using an RNA-seq approach. The gene expression data reveal indications that L. minor plants exposed at lower dose rates, can tolerate the exposure by triggering acclimation responses. In contrast, at the highest dose rate tested, a high number of genes related to antioxidative defense systems, DNA repair and cell cycle were differentially expressed suggesting that only high dose rates of ionising radiation drive L. minor plants into survival strategies. Notably, the photosynthetic process seems to be unaffected in L. minor plants among the tested dose rates. This study, supported by our earlier work, clearly indicates that plants shift from acclimation responses towards survival responses at increasing dose rates of ionising radiation. Copyright © 2017 Elsevier B.V. All rights reserved.

Response of Lemna minor L. to short-term cobalt exposure: The effect on photosynthetic electron transport chain and induction of oxidative damage

International Nuclear Information System (INIS)

Begović, Lidija; Mlinarić, Selma; Antunović Dunić, Jasenka; Katanić, Zorana; Lončarić, Zdenko; Lepeduš, Hrvoje; Cesar, Vera

2016-01-01

Highlights: • Cobalt (Co"2"+) impaired the function of oxygen evolving complex (OEC) in L. minor L. • Electron transport through PSII components varied depending on Co"2"+ concentration. • K-band was proven to be suitable parameter for investigation of Co"2"+ toxicity. • Increased lipid peroxidation level showed early oxidative damage induced by Co"2"+. - Abstract: The effect of two concentrations of cobalt (Co"2"+) on photosynthetic activity and antioxidative response in Lemna minor L. were assessed 24, 48 and 72 h after the start of the exposure. Higher concentration of cobalt (1 mM) induced growth inhibition while lower concentration (0.01 mM) increased photosynthetic pigments content. Analysis of chlorophyll a fluorescence transients revealed high sensitivity of photosystem II primary photochemistry to excess of Co"2"+ especially at the higher concentration where decreased electron transport beyond primary quinone acceptor Q_A"− and impaired function of oxygen evolving complex (OEC) was observed. Due to impairment of OEC, oxygen production was decreased at higher Co"2"+ concentration. Activity of superoxide dismutase was mainly inhibited while lipid peroxidation increased, at both concentrations, indicating that cobalt-induced oxidative damage after short exposure and moreover, susceptibility of the membranes in the cell to cobalt toxicity. Results obtained in this study suggest possible application of used parameters as tools in assessment of early damage caused by metals.

Dried duckweed and commercial feed promote adequate growth performance of tilapia fi ngerlings

OpenAIRE

Tavares, Flávia de A.; Rodrigues, João Bosco R.; Fracalossi, Débora Machado; Esquivel, Juan; Roubach, Rodrigo

2008-01-01

http://dx.doi.org/10.5007/2175-7925.2008v21n3p91Desempenho de alevinos de tilapia nilótica alimentados com uma  combinação de lemnas secas e ração comercial. O presente estudo  avaliou a utilização de ração comercial e lemna seca no cultivo de  alevinos de tilápias nilóticas com o objetivo de reduzir os custos de produção. Três dietas representadas por lemna seca, ração comercial  (40% proteína bruta) e uma combinação de lemna seca e ração  comercial foram fornecidas a um grupo de 20 alevinos...

Combined effects of elevated CO_2 and Cd-contaminated water on growth, photosynthetic response, Cd accumulation and thiolic components status in Lemna minor L

International Nuclear Information System (INIS)

Pietrini, F.; Bianconi, D.; Massacci, A.; Iannelli, M.A.

2016-01-01

Highlights: • Elevated CO_2 did not affect the ability of L. minor plants to accumulate Cd in their tissues. • Elevated CO_2 decreased Cd toxicity in L. minor plants by increasing photosynthesis. • Elevated CO_2 reduced Cd toxicity in duckweed by enhancing antioxidant system. - Abstract: The objective of this study was to investigate the combined effects of elevated CO_2 and cadmium (Cd) treatments on growth, photosynthetic efficiency and phytoremediation ability in Lemna minor L. Plants of L. minor were exposed to different Cd concentrations (0, 1.5, 2.5 and 5 mg L"−"1 Cd) for periods of 24, 48 and 72 h at ambient (AC) and at elevated (EC) CO_2 (350 and 700 ppm, respectively). Cadmium concentration, bioconcentration factor, enzyme activities and thiols content enhanced in plants with the increase of Cd treatments, time of exposure and at both CO_2 levels. Glutathione levels increased only at AC. Growth, photosynthetic and chlorophyll fluorescence parameters, and the reduced glutathione to oxidized glutathione ratio declined in plants with increasing exposure time, Cd treatments and at both CO_2 levels. Our results suggested that the alleviation of toxicity, at low Cd doses, observed in L. minor grown at EC is dependent on both increased photosynthesis and an enhanced antioxidant capacity.

Mercury induced oxidative stress, DNA damage, and activation of antioxidative system and Hsp70 induction in duckweed (Lemna minor).

Science.gov (United States)

Zhang, Tingting; Lu, Qianqian; Su, Chunlei; Yang, Yaru; Hu, Dan; Xu, Qinsong

2017-09-01

Mercury uptake and its effects on physiology, biochemistry and genomic stability were investigated in Lemna minor after 2 and 6d of exposure to 0-30μM Hg. The accumulation of Hg increased in a concentration- and duration-dependent manner, and was positively correlated with the leaf damage. Oxidative stress after Hg exposure was evidenced in L. minor by a significant decrease in photosynthetic pigments, an increase in malondialdehyde and lipoxygenase activities (total enzyme activity and isoenzymes activity). Fronds of L. minor exposed to Hg showed an induction of peroxidase, catalase, and ascorbate peroxidase activities (total enzyme activity and some isoenzymes activities). Exposure of L. minor to Hg reduced the activity (total enzyme activity and some isoenzymes activities) of glutathione reductase, and superoxide dismutase. Exposure to Hg produced a transient increase in the content of glutathione and ascorbic acid. The content of dehydroascorbate and oxidized glutathione in L. minor were high during the entire exposure period. Exposure of L. minor to Hg also caused the accumulation of proline and soluble sugars. The amplification of new bands and the absence of normal DNA amplicons in treated plants in the random amplified polymorphic DNA (RAPD) profile indicated that genomic template stability (GTS) was affected by Hg treatment. The accumulation of Hsp70 indicated the occurrence of a heat shock response at all Hg concentrations. These results suggest that L. minor plants were able to cope with Hg toxicity through the activation of various mechanisms involving enzymatic and non-enzymatic antioxidants, up-regulation of proline, and induction of Hsp70. Copyright © 2017 Elsevier Inc. All rights reserved.

DAMAGE TO DNA PRIMARY STRUCTURE AND ANTIOXIDANT ENZYMES IN LEMNA MINOR INDUCED BY HG2+%Hg2+ 胁迫对浮萍体细胞DNA一级结构和抗氧化酶系的损伤

Institute of Scientific and Technical Information of China (English)

徐楠; 施国新; 曾晓敏; 丁小余; 徐勤松; 陈源

2003-01-01

主要从DNA一级结构及抗氧化酶系变化两方面,研究了Hg2+胁迫下浮萍体细胞的损伤.结果表明:运用随机扩增多态性DNA法(Random amplified polymorphism DNA, RAPD)和DNA梯法(DNA Ladder),5～10 mg*L-1 Hg2+处理组可检测到基因组DNA的明显损伤,20 mg*L-1Hg2+已导致细胞坏死;RAPD法较DNA Ladder法更灵敏.本文还发现,活性氧和抗氧化酶系很可能参与了浮萍体细胞凋亡过程.低浓度的Hg2+胁迫可刺激抗氧化酶活性升高,以清除体内活性氧,而一旦活性氧水平超出一定域值,抗氧化酶活性急速下降,导致细胞凋亡.%The damage to Lemna minor cells induced by Hg2+ was studied in this article. Most damage occurred to DNA primary structure and changes in antioxidant enzyme activities were investigated by using RAPD and DNA ladder methods. The results showed that obvious damage to DNA was found in the process of apoptosis induced by 5-10 mg*L-1 Hg2+, and 20 mg*L-1 Hg2+ had already caused necrotic injury. The RAPD method was the more sensitive of the two methods, and so could be considered as an important method for monitoring apoptosis. The results also indicated that reactive oxygen species (ROS) and antioxidant enzymes are involved in the process of apoptosis. The activities of antioxidant enzymes could be stimulated to eliminate active oxygen by exposing the Lemna minor to low Hg2+ concentration; the cells declined rapidly when ROS were unable to be eliminated effectively.

Carbon-Flow-Based Modeling of Ecophysiological Processes and Biomass Dynamics of Submersed Aquatic Plants

National Research Council Canada - National Science Library

Best, Elly P. H; Boyd, William A

2007-01-01

...], Potamogeton pectinatus [POTAM], Hydrilla verticillata [HYDRIL], and Myriophyllum spicatum [MILFO]. These plant species are similar in growth strategy but differ significantly in morphology and physiology...

The first toxicological study of the antiozonant and research tool ethylene diurea (EDU) using a Lemna minor L. bioassay: Hints to its mode of action.

Science.gov (United States)

Agathokleous, Eugenios; Mouzaki-Paxinou, Akrivi-Chara; Saitanis, Costas J; Paoletti, Elena; Manning, William J

2016-06-01

The antiozonant and research tool ethylene diurea (EDU) is widely studied as a phytoprotectant against the widespread pollutant ground-surface ozone. Although it has been extensively used, its potential toxicity in the absence of ozone is unknown and its mode of action is unclear. The purpose of this research was to toxicologically assess EDU and to further investigate its mode of action using Lemna minor L. as a model organism. Application of EDU concentrations greater than 593 mg L(-1) (practically 600 mg L(-1)) resulted in adverse inhibition of colony growth. As no-observed-toxic-effects concentration (NOEL) we recommend a concentration of 296 mg L(-1) (practically 300 mg L(-1)). A hormetic response was detected, i.e. stimulatory effects of low EDU concentrations, which may indicate overcompensation in response to disruption in homeostasis. Growth inhibition and suppressed biomass were associated with impacted chlorophyll a fluorescence (ΦPSII, qP and ETR). Furthermore, EDU increased mesophyll thickness, as indicated by frond succulence index. Applications of concentrations ≥593 mg L(-1) to uncontrolled environments should be avoided due to potential toxicity to sensitive organisms and the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

ACCUMULATION OF RECOMBINANT FUSION PROTEIN – SECRETORY ANALOG OF Ag85B AND ESAT6 MYCOBACTERIUM TUBERCULOSIS PROTEINS – IN TRANSGENIC Lemna minor L. PLANTS

Directory of Open Access Journals (Sweden)

A.A.Peterson

2015-10-01

Full Text Available Determination of the presence of the recombinant fusion protein (ESAT6-Ag85B(ΔTMD-6His and its accumulation level in duckweed plants (Lemna minor L. was the aim of the research. ESAT6 and Ag85B are secretory proteins of Mycobacterium tuberculosis and are considered as potential candidates for development of new vaccine against tuberculosis (TB. Transgenic duckweed plants were obtained previously by Agrobacterium rhizogenes-mediated transformation and possessed fusion gene sequence esxA-fbpBΔTMD. Specific polyclonal antibodies were produced in immunized mice to identify levels of accumulation of TB antigens in plants. Recombinant antigen used for mice immunization was obtained in our laboratory by expression in E. coli. Western blot analysis revealed the recombinant tuberculosis antigen ESAT6-Ag85B(ΔTMD-6His in extracts from transgenic L. minor plants. The level of accumulation of the protein corresponds to 0.4-0.5 µg protein per 1 g of fresh weight of plant. Additionally, the accumulation of recombinant protein was investigated in lyophilized transgenic plants after 1.5 year storage. Duckweed plants accumulating a recombinant analogue of M. tuberculosis secretory proteins can be used for development of plant-based edible vaccines.

Exposure to radiofrequency radiation induces oxidative stress in duckweed Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Tkalec, Mirta [Department of Botany, Division of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, HR-10000 Zagreb (Croatia)], E-mail: mtkalec@zg.biol.pmf.hr; Malaric, Kresimir [Faculty of Electrical Engineering and Computing, University of Zagreb, Unska 3, HR-10000 Zagreb (Croatia); Pevalek-Kozlina, Branka [Department of Botany, Division of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, HR-10000 Zagreb (Croatia)

2007-12-15

Widespread use of radiofrequency radiation emitting devices increased the exposure to electromagnetic fields (EMFs) from 300 MHz to 300 GHz. Various biological effects of exposure to these fields have been documented so far, but very little work has been carried out on plants. The aim of the present work was to investigate the physiological responses of the plant Lemna minor after exposure to radiofrequency EMFs, and in particular, to clarify the possible role of oxidative stress in the observed effects. Duckweed was exposed for 2 h to EMFs of 400 and 900 MHz at field strengths of 10, 23, 41 and 120 V m{sup -1}. The effect of a longer exposure time (4 h) and modulation was also investigated. After exposure, parameters of oxidative stress, such as lipid peroxidation, H{sub 2}O{sub 2} content, activities and isoenzyme pattern of antioxidative enzymes as well as HSP70 expression were evaluated. At 400 MHz, lipid peroxidation and H{sub 2}O{sub 2} content were significantly enhanced in duckweed exposed to EMFs of 23 and 120 V m{sup -1} while other exposure treatments did not have an effect. Compared to the controls, the activities of antioxidative enzymes showed different behaviour: catalase (CAT) activity increased after most exposure treatments while pyrogallol (PPX) and ascorbate peroxidase (APX) activities were not changed. Exceptions were reduced PPX and APX activity after longer exposure at 23 V m{sup -1} and increased PPX activity after exposures at 10 and 120 V m{sup -1}. By contrast, at 900 MHz almost all exposure treatments significantly increased level of lipid peroxidation and H{sub 2}O{sub 2} content but mostly decreased PPX activity and did not affect CAT activity. Exceptions were exposures to a modulated field and to the field of 120 V m{sup -1} which increased PPX and CAT activity. At this frequency APX activity was significantly decreased after exposure at 10 V m{sup -1} and longer exposure at 23 V m{sup -1} but it increased after a shorter exposure at

Exposure to radiofrequency radiation induces oxidative stress in duckweed Lemna minor L

International Nuclear Information System (INIS)

Tkalec, Mirta; Malaric, Kresimir; Pevalek-Kozlina, Branka

2007-01-01

Widespread use of radiofrequency radiation emitting devices increased the exposure to electromagnetic fields (EMFs) from 300 MHz to 300 GHz. Various biological effects of exposure to these fields have been documented so far, but very little work has been carried out on plants. The aim of the present work was to investigate the physiological responses of the plant Lemna minor after exposure to radiofrequency EMFs, and in particular, to clarify the possible role of oxidative stress in the observed effects. Duckweed was exposed for 2 h to EMFs of 400 and 900 MHz at field strengths of 10, 23, 41 and 120 V m -1 . The effect of a longer exposure time (4 h) and modulation was also investigated. After exposure, parameters of oxidative stress, such as lipid peroxidation, H 2 O 2 content, activities and isoenzyme pattern of antioxidative enzymes as well as HSP70 expression were evaluated. At 400 MHz, lipid peroxidation and H 2 O 2 content were significantly enhanced in duckweed exposed to EMFs of 23 and 120 V m -1 while other exposure treatments did not have an effect. Compared to the controls, the activities of antioxidative enzymes showed different behaviour: catalase (CAT) activity increased after most exposure treatments while pyrogallol (PPX) and ascorbate peroxidase (APX) activities were not changed. Exceptions were reduced PPX and APX activity after longer exposure at 23 V m -1 and increased PPX activity after exposures at 10 and 120 V m -1 . By contrast, at 900 MHz almost all exposure treatments significantly increased level of lipid peroxidation and H 2 O 2 content but mostly decreased PPX activity and did not affect CAT activity. Exceptions were exposures to a modulated field and to the field of 120 V m -1 which increased PPX and CAT activity. At this frequency APX activity was significantly decreased after exposure at 10 V m -1 and longer exposure at 23 V m -1 but it increased after a shorter exposure at 23 V m -1 . At both frequencies no differences in isoenzyme

Optimization of methodology by X-ray fluorescence for the metals determination in aquatic plants of the high course of the Lerma river

International Nuclear Information System (INIS)

Albino P, E.

2015-01-01

The high course of the Lerma river has a pollution problem in its hydrological system due to discharges of urban wastewater and industrial areas; the pollutants that affect the hydrological system are metals, which are absorbed by living organisms and probably incorporated into the food chain. For this reason in this work the technique of X-ray fluorescence total reflection was applied in six species of aquatic plants that grow in the high course of the Lerma river: Arroyo Mezapa (Eichhornia crassipes, Juncus efusus, Hydrocotyle, Schoenoplectus validus) Ameyalco river (Lemna gibba) and Atarasquillo river (Berula erecta) in order to evaluate the metals concentration (Cr, Mn, Fe, Ni, Cu, Zn and Pb) as well as the translocation factor and bioaccumulation factor for each aquatic species. According to the results, was observed that the highest concentration of metals is located in the deeper parts; metals which present a significant concentration are Mn and Fe in the six species of aquatic plants. According to the translocation factor the species having a higher translocation of metals are: Juncus efusus in Mn (1.19 mg/L) and Zn (1.31 mg/L), Hydrocotyle (1.14 mg/L), the species Eichhornia crassipes not show translocation. For bioaccumulation factor, was observed that the most bioaccumulation of metals is found in the soluble fraction of the six species of aquatic plants, especially Fe followed of Cu and Zn. Also was considered that the Berula erecta plant had a higher bioaccumulation of metals such as Cr, Mn, Fe, Cu and Zn so it can be considered as a hyper-accumulating species of these elements. With the results can be considered that the technique of X-ray fluorescence total reflection is 95% reliable to determine the concentration of metals within the structures of the aquatic plants used for this study. (Author)

Optimization of methodology by X-ray fluorescence for the metals determination in aquatic plants of the high course of the Lerma river; Optimizacion de la metodologia por fluorescencia de rayos X para la determinacion de metales en plantas acuaticas del curso alto del Rio Lerma

Energy Technology Data Exchange (ETDEWEB)

Albino P, E.

2015-07-01

The high course of the Lerma river has a pollution problem in its hydrological system due to discharges of urban wastewater and industrial areas; the pollutants that affect the hydrological system are metals, which are absorbed by living organisms and probably incorporated into the food chain. For this reason in this work the technique of X-ray fluorescence total reflection was applied in six species of aquatic plants that grow in the high course of the Lerma river: Arroyo Mezapa (Eichhornia crassipes, Juncus efusus, Hydrocotyle, Schoenoplectus validus) Ameyalco river (Lemna gibba) and Atarasquillo river (Berula erecta) in order to evaluate the metals concentration (Cr, Mn, Fe, Ni, Cu, Zn and Pb) as well as the translocation factor and bioaccumulation factor for each aquatic species. According to the results, was observed that the highest concentration of metals is located in the deeper parts; metals which present a significant concentration are Mn and Fe in the six species of aquatic plants. According to the translocation factor the species having a higher translocation of metals are: Juncus efusus in Mn (1.19 mg/L) and Zn (1.31 mg/L), Hydrocotyle (1.14 mg/L), the species Eichhornia crassipes not show translocation. For bioaccumulation factor, was observed that the most bioaccumulation of metals is found in the soluble fraction of the six species of aquatic plants, especially Fe followed of Cu and Zn. Also was considered that the Berula erecta plant had a higher bioaccumulation of metals such as Cr, Mn, Fe, Cu and Zn so it can be considered as a hyper-accumulating species of these elements. With the results can be considered that the technique of X-ray fluorescence total reflection is 95% reliable to determine the concentration of metals within the structures of the aquatic plants used for this study. (Author)

LA VEGETACIÓN DEL HUMEDAL DE JABOQUE (BOGOTÁ, D.C.

Directory of Open Access Journals (Sweden)

Hernández Juliana

2009-12-01

Full Text Available Con base en los lineamientos metodológicos de la escuela sigmatista-Zurich-Montpellier, se diferenciaron 14 comunidades vegetales que se distribuyen en losdiferentes ambientes que incluye una serie ecológica hídrica en el humedal deJaboque, Bogotá, Colombia. En la vegetación de ribera predominan los juncalesde Schoenoplectus californicus, de Juncus effusus y el totoral de Typha latifolia.En ambientes pantanosos ya sea en las orillas o en zonas que se han terrizado alinterior de la cubeta, arraigan los herbazales de Polypogon elongatum, de Rumexconglomeratus y el cortaderal de Carex luridiformis. En las zonas de transiciónentre los ambientes acuáticos y continentales, se ubican los camalotales, vegetaciónsemiarraigada dominada por Bidens laevis, que se asocia con Ludwigia peploides,Hydrocotyle ranunculoides y Polygonum punctatum. En los reducidos espejos deagua, se establecen las comunidades fl otantes de Eichhornia crassipes, Limnobiumlaevigatum y Lemna gibba. En general la diversidad fl orística de especies y decomunidades es mayor en la parte más amplia y en mejor estado de conservación delhumedal, en cercanías al Parque de La Florida, donde se encuentran representadascasi todas las comunidades vegetales reseñadas en esta contribución. En la zonade mayor transformación (área canalizada, se establecen pocas comunidades,predominan el camalotal de Bidens laevis, el herbazal de Polygonum punctatum(barbasco y los pastizales con Pennisetum clandestinum (kikuyo y Polypogonelongatus. La mayoría de las comunidades vegetales registradas en Jaboque tienendistribución amplia en lagos, lagunas y pantanos andinos, con especial signifi canciaen la sabana de Bogotá y en el altiplano cundi-boyacense.

Response of Lemna minor L. to short-term cobalt exposure: The effect on photosynthetic electron transport chain and induction of oxidative damage

Energy Technology Data Exchange (ETDEWEB)

Begović, Lidija, E-mail: lbegovic@biologija.unios.hr [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia); Mlinarić, Selma, E-mail: smlinaric@biologija.unios.hr [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia); Antunović Dunić, Jasenka, E-mail: jantunovic@biologija.unios.hr [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia); Katanić, Zorana, E-mail: zkatanic@biologija.unios.hr [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia); Lončarić, Zdenko, E-mail: zdenko.loncaric@pfos.hr [Faculty of Agriculture, Josip Juraj Strossmayer University of Osijek, Ulica kralja Petra Svačića 1d, H R -31000 Osijek (Croatia); Lepeduš, Hrvoje, E-mail: hlepedus@yahoo.com [Faculty of Humanities and Social Sciences, Josip Juraj Strossmayer University of Osijek, Lorenza Jägera 9, HR-31000 Osijek (Croatia); Cesar, Vera, E-mail: vcesarus@yahoo.com [Josip Juraj Strossmayer University of Osijek, Department of Biology, Ulica cara Hadrijana 8/A, H R -31000 Osijek (Croatia)

2016-06-15

Highlights: • Cobalt (Co{sup 2+}) impaired the function of oxygen evolving complex (OEC) in L. minor L. • Electron transport through PSII components varied depending on Co{sup 2+} concentration. • K-band was proven to be suitable parameter for investigation of Co{sup 2+} toxicity. • Increased lipid peroxidation level showed early oxidative damage induced by Co{sup 2+}. - Abstract: The effect of two concentrations of cobalt (Co{sup 2+}) on photosynthetic activity and antioxidative response in Lemna minor L. were assessed 24, 48 and 72 h after the start of the exposure. Higher concentration of cobalt (1 mM) induced growth inhibition while lower concentration (0.01 mM) increased photosynthetic pigments content. Analysis of chlorophyll a fluorescence transients revealed high sensitivity of photosystem II primary photochemistry to excess of Co{sup 2+} especially at the higher concentration where decreased electron transport beyond primary quinone acceptor Q{sub A}{sup −} and impaired function of oxygen evolving complex (OEC) was observed. Due to impairment of OEC, oxygen production was decreased at higher Co{sup 2+} concentration. Activity of superoxide dismutase was mainly inhibited while lipid peroxidation increased, at both concentrations, indicating that cobalt-induced oxidative damage after short exposure and moreover, susceptibility of the membranes in the cell to cobalt toxicity. Results obtained in this study suggest possible application of used parameters as tools in assessment of early damage caused by metals.

Fabrication and characterization of mesoporous activated carbon from Lemna minor using one-step H3PO4 activation for Pb(II) removal

Science.gov (United States)

Huang, Yang; Li, Shunxing; Lin, Haibin; Chen, Jianhua

2014-10-01

A low cost and locally available material, Lemna minor, was used to fabricate activated carbon using H3PO4 activation. After H3PO4 activation, the L. minor activated carbons (LACs) possess high mesoporosity (92.2%) and a surface area of 531.9 m2/g according to Brunauer-Emmett-Teller (BET) analysis. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectrometer (XPS) analyses reveal the presence of rich hydroxyl, carboxyl, amide and phosphate functional groups on the LACs surface, leading to facile Pb(II) binding to the surface through strong chemisorptive bonds or ion-exchange. The kinetic and equilibrium data were well described by pseudo-first-order model and Langmuir isotherm, with the maximum monolayer adsorption capacity (qm) 170.9 mg/g at 25 °C. The intra-particle diffusion mechanism was partially responsible for the adsorption. The adsorption process was spontaneous and endothermic with negative ΔG and positive ΔH. The Pb(II)-loaded LACs could be easily regenerated using 0.1-M HCl and reused for seven cycles without significant adsorption capacity reduction. The maximum percentage removal rate for Pb(II) (20 mg/L) was found to be 91.8% within 30 min, at optimum conditions of pH 6.0 and 25 °C. These suggested that the low-cost LACs could be used as a potential adsorbent in the treatment of lead-contaminated water.

Characterization of indole acetic acid endophyte producers in ...

African Journals Online (AJOL)

Valued Acer Customer

2015-02-18

Feb 18, 2015 ... the number and identity of the isolated endophyte phytobacteria in L. gibba plants .... mL was taken from each sample and placed on plates containing ... databases using Basic Logical Alignment Search Tool analysis ...

Dried duckweed and commercial feed promote adequate growth performance of tilapia fingerlings

Directory of Open Access Journals (Sweden)

Flávia de A. Tavares

2008-01-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2008v21n3p91 Desempenho de alevinos de tilapia nilótica alimentados com uma  combinação de lemnas secas e ração comercial. O presente estudo  avaliou a utilização de ração comercial e lemna seca no cultivo de  alevinos de tilápias nilóticas com o objetivo de reduzir os custos de produção. Três dietas representadas por lemna seca, ração comercial  (40% proteína bruta e uma combinação de lemna seca e ração  comercial foram fornecidas a um grupo de 20 alevinos de tilápia  (Oreochromis niloticus em triplicata. Peixes com peso médio 3,2 ±  0,94g foram estocados em nove tanques-rede com volume de 1-m3 e  alimentados duas vezes ao dia durante um período de 50 dias. O peso  médio final dos alevinos alimentados com ração comercial (21,67 g e  50% ração +50% lemna seca (19,53 g não diferiram estatisticamente  (p<0,05. Paralelamente, os peixes pertencentes aos mesmos tratamentos não apresentaram diferença significativa no crescimento específico. O ganho em peso foi menor em temperaturas mais baixas ao longo do período experimental, causando um aumento significativo na conversão alimentar principalmente dos alevinos alimentados apenas com lemna seca. Além disso, a dieta composta apenas de lemna seca proporcionou o menor ganho em peso e taxa de crescimento específico. Através dos resultados obtidos, conclui-se que a lemna seca pode substituir até 50% (matéria seca 1:1 da ração  comercial (40% proteína bruta utilizada na produção de alevinos de tilápia por um período de 50 dias, sem apresentar redução no crescimento.

Combined effects of elevated CO{sub 2} and Cd-contaminated water on growth, photosynthetic response, Cd accumulation and thiolic components status in Lemna minor L

Energy Technology Data Exchange (ETDEWEB)

Pietrini, F.; Bianconi, D.; Massacci, A. [Institute of Agro-Environmental and Forest Biology, National Research Council of Italy, Via Salaria Km 29,300, 00015 Monterotondo Scalo, Roma (Italy); Iannelli, M.A., E-mail: adelaide.iannelli@ibba.cnr.it [Institute of Agricultural Biology and Biotechnology, National Research Council of Italy, Via Salaria Km 29,300, 00015 Monterotondo Scalo, Roma (Italy)

2016-05-15

Highlights: • Elevated CO{sub 2} did not affect the ability of L. minor plants to accumulate Cd in their tissues. • Elevated CO{sub 2} decreased Cd toxicity in L. minor plants by increasing photosynthesis. • Elevated CO{sub 2} reduced Cd toxicity in duckweed by enhancing antioxidant system. - Abstract: The objective of this study was to investigate the combined effects of elevated CO{sub 2} and cadmium (Cd) treatments on growth, photosynthetic efficiency and phytoremediation ability in Lemna minor L. Plants of L. minor were exposed to different Cd concentrations (0, 1.5, 2.5 and 5 mg L{sup −1} Cd) for periods of 24, 48 and 72 h at ambient (AC) and at elevated (EC) CO{sub 2} (350 and 700 ppm, respectively). Cadmium concentration, bioconcentration factor, enzyme activities and thiols content enhanced in plants with the increase of Cd treatments, time of exposure and at both CO{sub 2} levels. Glutathione levels increased only at AC. Growth, photosynthetic and chlorophyll fluorescence parameters, and the reduced glutathione to oxidized glutathione ratio declined in plants with increasing exposure time, Cd treatments and at both CO{sub 2} levels. Our results suggested that the alleviation of toxicity, at low Cd doses, observed in L. minor grown at EC is dependent on both increased photosynthesis and an enhanced antioxidant capacity.

Valor nutricional de Lemna valdiviana Phil (Araceae submetida a diferentes concentrações de fertilização com excremento de aves

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Graça Maria de Oliveira França

2009-06-01

Full Text Available http://dx.doi.org/10.5007/2175-7925.2009v22n3p19 As lemnaceas são plantas aquáticas com grande potencial de uso como matéria prima para ração de peixes devido ao alto valor nutricional. O objetivo deste estudo foi avaliar a composição química e a qualidade nutricional de Lemna valdiviana submetida a diferentes concentrações de adubação com excremento de aves. O experimento foi realizado em delineamento inteiramente casualizado com três repetições. Os tratamentos foram: Controle (sem adubação; T1 – 150g.m-3, T2 – 300g.m-3 e T3 – 450 g.m-3 de excremento de aves fresco, distribuídos em dose única para fertilizar o cultivo de L. valdiviana. A dose que proporcionou a melhor qualidade nutricional de L. valdiviana foi 450g.m-3 de excremento de aves, com teor de proteína bruta de 19,66% na matéria seca, percentual de fibras de 13,06% e teor de 0,26% de P, 1, 63% de N, 0,37% de Na e 1,22% de Ca na massa seca. Os teores alcançados nesse estudo indicam a possibilidade da L. valdiviana ser considerada uma matéria prima de boa qualidade nutricional para ser utilizada em outros experimentos como complemento na ração para peixes.

Effect of zinc and lead on the physiological and biochemical properties of aquatic plant Lemna minor: its potential role in phytoremediation

Science.gov (United States)

Jayasri, M. A.; Suthindhiran, K.

2017-06-01

Plants have gained importance in situ bioremediation of heavy metals. In the present study, different concentrations of zinc (Zn2+) (0.5, 5, 10, 15, 20 mg/l) and lead (Pb2+) (1, 2, 4, 6, 8 mg/l) were used to evaluate metal tolerance level of Lemna minor. L.minor were exposed to metals for 4 days and tested for its dry to fresh weight ratio (DW/FW), photosynthetic pigments production and protein content. The oxidative damage was detected by measuring catalase activity. L.minor showed tolerance against Zn2+ and Pb2+ at a concentration of 10 and 4 mg/l, respectively. Among the metals, Pb2+ showed a significant toxicity at 8 mg/l. High concentration (20 mg/l of Zn2+ and 8 mg/l of Pb2+) of the metals displayed a considerable negative effect on soluble proteins (13 fold decrease with Zn2+ and 4 fold decrease with Pb2+) and photosynthetic pigments (twofold decrease with Zn2+ and onefold decrease with Pb2+) and lead to a consequent reduction in number of fronds. Further, the catalase was greatly increased (twofold decrease with Zn2+ and sixfold decrease with Pb2+) under metal stress. The results indicate that L.minor withstands Zn2+ and Pb2+ toxicity up to the concentration of 10 and 4 mg/l, respectively. Hence, the metal tolerant property of this plant shall be exploited for bioremediation of Zinc and Lead in polluted water. Further, the detailed and wide range of heavy metal toxicity studies should be done to reveal the possible use of this plant on large scale bioremediation purpose.

Toxicidade aguda e risco ambiental do antibiótico oxitetraciclina para tilápia ( Oreochromis niloticus , Daphnia magna e Lemna minor

Directory of Open Access Journals (Sweden)

A.A. Machado

Full Text Available RESUMO O objetivo deste estudo foi classificar o antibiótico Terramicina(r de acordo com a toxicidade aguda e o risco de intoxicação ambiental para Oreochromis niloticus, Daphnia magna e Lemna minor, com base no seu ingrediente ativo oxitetraciclina (OTC. Além disso, observou-se a ocorrência de sinais de intoxicação aguda em peixes e o efeito da diluição do antibiótico sobre as variáveis de qualidade de água. Alevinos, neonatos e frondes foram expostos a concentrações de OTC. De acordo com os resultados dos testes de toxicidade aguda, a Terramicina(r foi classificada pela toxicidade aguda e pelo risco de intoxicação ambiental. Para O. niloticus, a CL(I50; 48h calculada foi de 6,92 mg L-1, para D. magna a CE(I50; 48h foi de 0,17mg.L-1, enquanto para L. minor a CI(I50;7d foi de 0,68 mg L-1. A Terramicina(r foi classificada como muito tóxica para O. niloticus e extremamente tóxica para D. magna e L. minor e causa risco de intoxicação ambiental para os três organismos testados. Concentrações de 7,5 e 8,0 mg L-1 de OTC reduziram a concentração de oxigênio dissolvido na água. De acordo com este estudo, a Terramicina(r não deve ser utilizada na aquicultura, pois é altamente tóxica e causa risco de intoxicação ambiental aos organismos teste.

Citric acid enhanced the antioxidant defense system and chromium uptake by Lemna minor L. grown in hydroponics under Cr stress.

Science.gov (United States)

Sallah-Ud-Din, Rasham; Farid, Mujahid; Saeed, Rashid; Ali, Shafaqat; Rizwan, Muhammad; Tauqeer, Hafiz Muhammad; Bukhari, Syed Asad Hussain

2017-07-01

Phytoextraction is a cost-effective and eco-friendly technique for the removal of pollutants, mainly heavy metal(loids) especially from polluted water and metal-contaminated soils. The phytoextraction of heavy metals is, in general, limited due to the low availability of heavy metals in the growth medium. Organic chelators can help to improve the phytoextraction by increasing metal mobility and solubility in the growth medium. The present research was carried out to examine the possibility of citric acid (CA) in improving chromium (Cr) phytoextraction by Lemna minor (duckweed). For this purpose, healthy plants were collected from nearby marsh and grown in hydroponics under controlled conditions. Initial metal contents of both marsh water and plant were measured along with physico-chemical properties of the marsh water. Different concentrations of Cr and CA were applied in the hydroponics in different combinations after defined intervals. Continuous aeration was supplied and pH maintained at 6.5 ± 0.1. Results showed that increasing concentration of Cr significantly decreased the plant biomass, photosynthetic pigments, leaf area, and antioxidant enzyme activities (like catalase, ascorbate peroxidase, superoxide dismutase, peroxidase). Furthermore, Cr stress increased the Cr concentrations, electrolyte leakage, hydrogen peroxide, and malondialdehyde contents in plants. The addition of CA alleviated the Cr-induced toxicity in plants and further enhanced the Cr uptake and its accumulation in L. minor. The addition of CA enhanced the Cr concentration in L. minor by 6.10, 26.5, 20.5, and 20.2% at 0, 10, 100, and 200 μM Cr treatments, respectively, compared to the respective Cr treatments without CA. Overall, the results of the present study showed that CA addition may enhance the Cr accumulation and tolerance in L. minor by enhancing the plant growth and activities of antioxidant enzymes.

Common Duckweed (Lemna minor) Is a Versatile High-Throughput Infection Model For the Burkholderia cepacia Complex and Other Pathogenic Bacteria

Science.gov (United States)

Thomson, Euan L. S.; Dennis, Jonathan J.

2013-01-01

Members of the Burkholderia cepacia complex (Bcc) have emerged in recent decades as problematic pulmonary pathogens of cystic fibrosis (CF) patients, with severe infections progressing to acute necrotizing pneumonia and sepsis. This study presents evidence that Lemna minor (Common duckweed) is useful as a plant model for the Bcc infectious process, and has potential as a model system for bacterial pathogenesis in general. To investigate the relationship between Bcc virulence in duckweed and Galleria mellonella (Greater wax moth) larvae, a previously established Bcc infection model, a duckweed survival assay was developed and used to determine LD50 values. A strong correlation (R2 = 0.81) was found between the strains’ virulence ranks in the two infection models, suggesting conserved pathways in these vastly different hosts. To broaden the application of the duckweed model, enteropathogenic Escherichia coli (EPEC) and five isogenic mutants with previously established LD50 values in the larval model were tested against duckweed, and a strong correlation (R2 = 0.93) was found between their raw LD50 values. Potential virulence factors in B. cenocepacia K56-2 were identified using a high-throughput screen against single duckweed plants. In addition to the previously characterized antifungal compound (AFC) cluster genes, several uncharacterized genes were discovered including a novel lysR regulator, a histidine biosynthesis gene hisG, and a gene located near the gene encoding the recently characterized virulence factor SuhBBc. Finally, to demonstrate the utility of this model in therapeutic applications, duckweed was rescued from Bcc infection by treating with bacteriophage at 6-h intervals. It was observed that phage application became ineffective at a timepoint that coincided with a sharp increase in bacterial invasion of plant tissue. These results indicate that common duckweed can serve as an effective infection model for the investigation of bacterial virulence

Influence of nutrient medium composition on uranium toxicity and choice of the most sensitive growth related endpoint in Lemna minor.

Science.gov (United States)

Horemans, Nele; Van Hees, May; Saenen, Eline; Van Hoeck, Arne; Smolders, Valérie; Blust, Ronny; Vandenhove, Hildegarde

2016-01-01

Uranium (U) toxicity is known to be highly dependent on U speciation and bioavailability. To assess the impact of uranium on plants, a growth inhibition test was set up in the freshwater macrophyte Lemna minor. First growth media with different compositions were tested in order to find a medium fit for testing U toxicity in L. minor. Following arguments were used for medium selection: the ability to sustain L. minor growth, a high solubility of U in the medium and a high percentage of the more toxic U-species namely UO2(2+). Based on these selection criteria a with a low phosphate concentration of 0.5 mg L(-1) and supplemented with 5 mM MES (2-(N-morpholino)ethanesulfonic acid) to ensure pH stability was chosen. This medium also showed highest U toxicity compared to the other tested media. Subsequently a full dose response curve for U was established by exposing L. minor plants to U concentrations ranging from 0.05 μM up to 150 μM for 7 days. Uranium was shown to adversely affect growth of L. minor in a dose dependent manner with EC10, EC30 and EC50 values ranging between 1.6 and 4.8 μM, 7.7-16.4 μM and 19.4-37.2 μM U, respectively, depending on the growth endpoint. Four different growth related endpoints were tested: frond area, frond number, fresh weight and dry weight. Although differences in relative growth rates and associated ECx-values calculated on different endpoints are small (maximal twofold difference), frond area is recommended to be used to measure U-induced growth effects as it is a sensitive growth endpoint and easy to measure in vivo allowing for measurements over time. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biosolubilization of uranyl ions in uranium ores by hydrophyte plants

International Nuclear Information System (INIS)

Cecal, Alexandru; Calmoi, Rodica; Melniciuc-Puica, Nicoleta

2006-01-01

This paper investigated the bioleaching of uranyl ions from uranium ores, in aqueous medium by hydrophyte plants: Lemna minor, Azolla caroliniana and Elodea canadensis under different experimental conditions. The oxidation of U(IV) to U(VI) species was done by the atomic oxygen generated in the photosynthesis process by the aquatic plants in the solution above uranium ores. Under identical experimental conditions, the capacity of bioleaching of uranium ores decreases according to the following series: Lemna minor > Elodea canadensis > Azolla caroliniana. The results of IR spectra suggest the possible use of Lemna minor and Elodea canadensis as a biological decontaminant of uranium containing wastewaters. (author)

Swelling and Degradation of Calcium-Pectic Gel Particles Made of Pectins of Silene vulgaris and Lemna minor Сallus Cultures at Different Concentrations of Pectinase in an Artificial Colon Environment

Directory of Open Access Journals (Sweden)

Anatoly A. Shubakov

2018-03-01

Full Text Available Spherical calcium-pectic gel particles (CaPGPs were obtained from pectins of callus cultures (CC of campion Silene vulgaris (silenan and duckweed Lemna minor (lemnan, as well as from commercial apple and citrus pectins by the method of ionotropic gelation. We studied the morphological characteristics of the obtained gel particles and found that the largest gel particles were formed from citrus pectin (CP, and the densest gel particles were formed from lemnan pectin (LP. The swelling and degradation of CaPGPs were comparatively evaluated by incubation in a simulated gastrointestinal environment. The swelling and degradation of CaPGPs formed from pectins of the silenan and lemnan callus cultures were studied at different concentrations of pectinase (0.4, 0.8 and 1.7 mg/ml in the simulated fluid of the colon. It has been established that the CaPGPs obtained from lemnan are more resistant to degradation in the simulated colon fluid than CaPGP obtained from silenan. It was shown that the concentration of pectinase in the simulated fluid of the colon and the type of pectin affect the degradability of CaPGPs formed on the basis of pectins of callus cultures.

Distribution and abundance of submerged aquatic macrophytes in a reactor cooling reservoir

Energy Technology Data Exchange (ETDEWEB)

Grace, J.B.

1977-08-01

Measurements of ash-free dry weight were used to characterize the effects of a heated effluent on submerged macrophytes in a reactor cooling reservoir. The species which were most abundant during the summers of 1974 and 1975 were Myriophyllum spicatum L. and Eleocharis acicularis (L.) R. and S. Examination of the vertical distribution of the shoot biomass of Myriophyllum revealed that plants in heated areas grew closer to the water surface than plants in unheated areas. The biomass of the second most abundant species, Eleocharis acicularis, was less at 0.5 m depths in heated areas (more than 5C/sup 0/ warmer than unheated areas) than at equal depths in unheated areas. Species diversity was greater at heated locations because of a greater equitability (i.e., evenness of distribution of biomass) among species.

UPTAKE AND PHYTOTRANSFORMATION OF ORGANOPHOSPHORUS PESTICIDES BY AXENICALLY CULTIVATED AQUATIC PLANTS

Science.gov (United States)

The uptake and phytotransformation of organophosphorus (OP) pesticides (malathion, demeton-S-methyl, and crufomate) was investigated in vitro using the axenically aquatic cultivated plants parrot feather (Myriophyllum aquaticum), duckweed (Spirodela oligorrhiza L.), and elodea (E...

Phytotoxic activity of the methanol leaves extract of Paullinia pinnata ...

African Journals Online (AJOL)

The activity of the extract against the growth of Lemna minor was used to investigate the phytotoxic activity. The activity of the methanol extract of P. pinnata leaves against Lemna minor increased in a dose- dependent manner and was significant at 1000 μg/ml. Therefore, the methanol leaves extract of P. pinnata exhibited ...

Possible role of jasmonic acid in the regulation of floral induction, evocation and floral differentiation in Lemna minor L.

Science.gov (United States)

Krajncic, B; Kristl, J; Janzekovic, I

2006-01-01

Jasmonic acid (JA) is implicated in a wide variety of developmental and physiological processes in plants. Here, we studied the effects of JA and the combination of JA and ethylenediamine-dio-hydroxyphenyl-acetic acid (EDDHA) on flowering in Lemna minor in axenical cultures. JA (0.475-47.5 nmol l(-1)) enhanced floral induction in L. minor under long-day (LD) conditions. Under the same conditions, at a concentration of 237.5 nmol l(-1), JA inhibited floral induction, and at a concentration of 475 nmol l(-1) it prevented floral induction. Under LD conditions with LD preculture, a combination of EDDHA (20,500 nmol l(-1)) and JA (47.5 nmol l(-1)) had a synergistic effect on the promotion of floral induction. Floral induction was enhanced to the greatest extent in experiments with LD precultures. Microscopic examination of microphotographs of histological sections showed that JA and, to an even greater extent, JA+EDDHA at optimal concentrations promote apical floral induction (evocation). Furthermore, JA, and to an even greater extent JA in combination with EDDHA in an optimal concentration, also promote flower differentiation, especially the development of stamens, as is evident from the microphotographs. The experimental results show that JA promotes floral induction in other species of Lemnaceae from various groups according to their photoperiodic response. The results support our hypothesis that, in addition to previously ascribed functions, JA may regulate floral induction, evocation and floral differentiation. Our hypothesis is supported also by the results obtained by quantitative determination of endogenous JA levels in L. minor at three growth stages. The levels of endogenous JA decreased from 389 ng JA g(-1) (fresh weight) of L. minor during the vegetative stage to 217 ng JA g(-1) during the evocation stage, and to 37.5 ng JA g(-1) during the flowering stage, which proves that JA is used for flowering.

Změny vodní vegetace NPR Břehyně – Pecopala v závislosti na rybářském hospodaření v letech 1997-2003

Czech Academy of Sciences Publication Activity Database

Adamec, Lubomír

-, - (2003), s. 103-108 ISSN 1211-3603 R&D Projects: GA MŽP SE/610/10/00 Institutional research plan: CEZ:AV0Z6005908 Keywords : Myriophyllum spicatum * grass carp * fishpond drawdown Subject RIV: EF - Botanics

Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Midwest Region

Science.gov (United States)

2008-09-01

Ceratophyllum demersum), bladderwort (Utricularia macrorhiza), white water crowfoot (Ranunculus longirostris), and duckweeds ( Lemna , Spirodela, and...divide the landscape into areas called map units. Map units usually contain more than one soil type or component. They often contain several minor ...bladderworts (Utricularia spp.), and duckweeds ( Lemna spp.) (Figure 36). Figure 36. Dried remains of water-lilies in a semipermanently ponded

Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Midwest Region (Version 2.0)

Science.gov (United States)

2010-08-01

bladderwort (Utricularia macrorhiza), white water crowfoot (Ranunculus longirostris), and duckweeds ( Lemna , Spirodela, and Wolffia). As mentioned...units. Map units usually contain more than one soil type or component. They often contain several minor components or inclusions of soils with...bladderworts (Utricularia spp.), and duckweeds ( Lemna spp.) (Figure 37). ERDC/EL TR-10-16 87 Figure 37. Dried remains of water-lilies in a

Decontamination of radioactive liquid wastes by hydrophytic vegetal organisms

International Nuclear Information System (INIS)

Cecal, Al; Popa, K.; Potoroaca, V.; Melniciuc-Puica, N.

2001-01-01

Bioaccumulation of some radioactive ions from contaminated waste solutions, on hydrophytic vegetal organisms is discussed. In order to follow the distribution of radioactive ions 137 Cs + , 60 Co 2+ and 51 Cr 3+ in various cell components extracted from Spirulina platensis, Porphiridium cruentum, Scenedesmus quadricauda, Lemna minor, Elodea canadensis, Pistia stratiotes and Riccia fluitans, the plants were cultivated in radioactive solutions. The resulting complexes were extracted with acetone or acetic acid and separated chromatographically. The results show an intense activity of the polysaccharide and lipoid fractions in the bioaccumulation process. The bioaccumulation varies in the series: Spirulina > Scenedesmus > Porphiridium > Riccia > Pistia > Lemna ≥ Elodea for 137 Cs + and 60 Co 2+ ; Spirulina > Porphiridium > Scenedesmus > Riccia > Pistia > Lemna > Elodea for 51 Cr 3+ . (author)

Phosphate uptake kinetics for four species of submerged freshwater macrophytes measured by a 33P phosphate radioisotope technique

DEFF Research Database (Denmark)

Christiansen, Nina Høj; Andersen, Frede Østergaard; Jensen, Henning S.

2016-01-01

Phosphate (Pi) uptake kinetics were determined in shoot and root tissues for four freshwater macrophyte species, Littorella uniflora, Potamogeton perfoliatus, Myriophyllum alterniflorum and Elodea canadensis, using a radioactive 33P phosphate technique. Collection of plant material in the oligotr...

The abundance and diversity of heterotrophic bacteria as a function of harvesting frequency of duckweed (Lemna minor L.) in recirculating aquaculture systems.

Science.gov (United States)

Ardiansyah, A; Fotedar, R

2016-07-01

Duckweed (Lemna minor L.) is a potential biofilter for nutrient removal and acts as a substrate for heterotrophic bacteria in recirculating aquaculture systems (RAS). Here, we determined the effects of harvesting frequency of duckweed on heterotrophic bacteria in RAS. Twelve independent RAS consisting of fish-rearing tank, biofilter tank and waste-collection tank were used to study the interactions between duckweed harvest frequencies up to 6 days and the composition, abundance and diversity of heterotrophic bacteria. After 36 days, heterotrophic bacteria in the biofilter tank were primarily Gram-negative cocci or ovoid, coccobacilli, Gram-negative bacilli and Gram-positive bacilli. Most bacterial genera were Bacillus and Pseudomonas while the least common was Acinetobacter. Duckweed harvested after every 2 days produced the highest specific growth rates (SGR) and total harvested biomass of duckweed, but harboured less abundant bacteria, whereas 6-day harvests had a higher growth index (GI) of duckweed than 2-day harvests, but caused a poor relationship between SGR and biomass harvest with the abundance and diversity of heterotrophic bacteria. Stronger correlations (R(2)  > 0·65) between duckweed SGR and biomass harvest with the heterotrophic bacteria diversity were observed at 4-day harvest frequency and the control. This study provides significant information on the interaction between the harvest frequency of duckweed and the composition, abundance and diversity of heterotrophic bacteria in recirculating aquaculture systems (RAS). Different harvest frequencies significantly influence the abundance and diversity of heterotrophic bacteria, which in turn may influence the nitrogen uptake efficiency of the system. The research is useful in improving the efficiency of removing nitrogenous metabolites in RAS directly by the duckweed and associated heterotrophic bacteria. © 2016 The Society for Applied Microbiology.

Common duckweed (Lemna minor is a versatile high-throughput infection model for the Burkholderia cepacia complex and other pathogenic bacteria.

Directory of Open Access Journals (Sweden)

Euan L S Thomson

Full Text Available Members of the Burkholderia cepacia complex (Bcc have emerged in recent decades as problematic pulmonary pathogens of cystic fibrosis (CF patients, with severe infections progressing to acute necrotizing pneumonia and sepsis. This study presents evidence that Lemna minor (Common duckweed is useful as a plant model for the Bcc infectious process, and has potential as a model system for bacterial pathogenesis in general. To investigate the relationship between Bcc virulence in duckweed and Galleria mellonella (Greater wax moth larvae, a previously established Bcc infection model, a duckweed survival assay was developed and used to determine LD50 values. A strong correlation (R(2 = 0.81 was found between the strains' virulence ranks in the two infection models, suggesting conserved pathways in these vastly different hosts. To broaden the application of the duckweed model, enteropathogenic Escherichia coli (EPEC and five isogenic mutants with previously established LD50 values in the larval model were tested against duckweed, and a strong correlation (R(2 = 0.93 was found between their raw LD50 values. Potential virulence factors in B. cenocepacia K56-2 were identified using a high-throughput screen against single duckweed plants. In addition to the previously characterized antifungal compound (AFC cluster genes, several uncharacterized genes were discovered including a novel lysR regulator, a histidine biosynthesis gene hisG, and a gene located near the gene encoding the recently characterized virulence factor SuhB(Bc. Finally, to demonstrate the utility of this model in therapeutic applications, duckweed was rescued from Bcc infection by treating with bacteriophage at 6-h intervals. It was observed that phage application became ineffective at a timepoint that coincided with a sharp increase in bacterial invasion of plant tissue. These results indicate that common duckweed can serve as an effective infection model for the investigation of bacterial

Characterizing dose response relationships: Chronic gamma radiation in Lemna minor induces oxidative stress and altered polyploidy level.

Science.gov (United States)

Van Hoeck, Arne; Horemans, Nele; Van Hees, May; Nauts, Robin; Knapen, Dries; Vandenhove, Hildegarde; Blust, Ronny

2015-12-01

The biological effects and interactions of different radiation types in plants are still far from understood. Among different radiation types, external gamma radiation treatments have been mostly studied to assess the biological impact of radiation toxicity in organisms. Upon exposure of plants to gamma radiation, ionisation events can cause, either directly or indirectly, severe biological damage to DNA and other biomolecules. However, the biological responses and oxidative stress related mechanisms under chronic radiation conditions are poorly understood in plant systems. In the following study, it was questioned if the Lemna minor growth inhibition test is a suitable approach to also assess the radiotoxicity of this freshwater plant. Therefore, L. minor plants were continuously exposed for seven days to 12 different dose rate levels covering almost six orders of magnitude starting from 80 μGy h(-1) up to 1.5 Gy h(-1). Subsequently, growth, antioxidative defence system and genomic responses of L. minor plants were evaluated. Although L. minor plants could survive the exposure treatment at environmental relevant exposure conditions, higher dose rate levels induced dose dependent growth inhibitions starting from approximately 27 mGy h(-1). A ten-percentage growth inhibition of frond area Effective Dose Rate (EDR10) was estimated at 95 ± 7 mGy h(-1), followed by 153 ± 13 mGy h(-1) and 169 ± 12 mGy h(-1) on fresh weight and frond number, respectively. Up to a dose rate of approximately 5 mGy h(-1), antioxidative enzymes and metabolites remained unaffected in plants. A significant change in catalase enzyme activity was found at 27 mGy h(-1) which was accompanied with significant increases of other antioxidative enzyme activities and shifts in ascorbate and glutathione content at higher dose rate levels, indicating an increase in oxidative stress in plants. Recent plant research hypothesized that environmental genotoxic stress conditions

三苯基锡对青萍生长及酶活性的影响%Toxic Effects of Triphenyltin on the Growth and the Related Enzymic Activities of Lemna minor

Institute of Scientific and Technical Information of China (English)

宋志慧; 刘歌

2010-01-01

以青萍(Lemna mino)为实验生物,通过研究不同浓度(0、0.04、0.08、0.12、0.16、0.20mg·L-1)的三苯基锡(TPT)对青萍生长发育及过氧化氢酶(CAT)和过氧化物酶(POD)活性的影响,初步探讨了TPT对水生浮萍植物的毒性作用,以期为及时发现并排除TPT污染提供理论和直观依据.实验结果表明:培养4d后,TPT对青萍叶片生长量的半数抑制浓度(IC50)为0.10mg·L-1;CAT、POD活性随TPT处理浓度的升高显著升高(各暴露组与对照组均差异显著,p＜0.05).结果显示,TPT对青萍具有明显的毒性作用,CAT和POD活性的变化可作为反映TPT污染胁迫的敏感指标.

Responses of antioxidant systems after exposition to rare earths and their role in chilling stress in common duckweed (Lemna minor L.): a defensive weapon or a boomerang?

Science.gov (United States)

Ippolito, M P; Fasciano, C; d'Aquino, L; Morgana, M; Tommasi, F

2010-01-01

Extensive agriculture application of rare earth elements (REEs) in Far East countries might cause spreading of these metals in aquatic and terrestrial ecosystems, thus inducing a growing concern about their environmental impact. In this work the effects of a mix of different REE nitrate (RE) and of lanthanum nitrate (LA) on catalase and antioxidant systems involved in the ascorbate-glutathione cycle were investigated in common duckweed Lemna minor L. The results indicated that L. minor shows an overall good tolerance to the presence of REEs in the media. Treatments at concentrations up to 5 mM RE and 5 mM LA did not cause either visible symptoms on plants or significant effects on reactive oxygen species (ROS) production, chlorophyll content, and lipid peroxidation. Toxic effects were observed after 5 days of exposition to 10 mM RE and 10 mM LA. A remarkable increase in glutathione content as well as in enzymatic antioxidants was observed before the appearance of the stress symptoms in treated plants. Duckweed plants pretreated with RE and LA were also exposed to chilling stress to verify whether antioxidants variations induced by RE and LA improve plant resistance to the chilling stress. In pretreated plants, a decrease in ascorbate and glutathione redox state and in chlorophyll content and an increase in lipid peroxidation and ROS production levels were observed. The use of antioxidant levels as a stress marker for monitoring REE toxicity in aquatic ecosystems by means of common duckweed is discussed.

USING ROTIFER POPULATION DEMOGRAPHIC PARAMETERS TO ASSESS IMPACTS OF THE DEGRADATION PRODUCTS FROM TRINITROTOLUENE PHYTOREMEDIATION

Science.gov (United States)

The objective of this study was to evaluate the aquatic chronic lethal and sublethal toxicity effects from the phytoremediation of water contaminated with 2,4,6-trinitrotoluene (2,4,6-TNT) by the wetland plant species Myriophyllum aquaticum (parrot feather). Rotifers (Brachionus...

Effects of linuron on a rooted aquatic macrophyte in sediment-dosed test systems

NARCIS (Netherlands)

Buresova, H.; Crum, S.J.H.; Belgers, J.D.M.; Adriaanse, P.I.; Arts, G.H.P.

2013-01-01

Effects of linuron on the sediment-rooted aquatic macrophyte Myriophyllum spicatum L. were studied in sediment-dosed test systems following a proposed guideline with extended test duration. Sediment, pore water, overlying water and macrophyte shoots were sampled weekly for chemical analyses. Linuron

Efficient distinction of invasive aquatic plant species from non-invasive related species using DNA barcoding

NARCIS (Netherlands)

Ghahramanzadeh, R.; Esselink, G.; Kodde, L.P.; Duistermaat, H.; Valkenburg, van J.L.C.H.; Marashi, S.H.; Smulders, M.J.M.; Wiel, van de C.C.M.

2013-01-01

Biological invasions are regarded as threats to global biodiversity. Among invasive aliens, a number of plant species belonging to the genera Myriophyllum, Ludwigia and Cabomba, and to the Hydrocharitaceae family pose a particular ecological threat to water bodies. Therefore, one would try to

Do varying aquatic plant species affect phytoplankton and crustacean responses to a nitrogen-permethrin mixture?

Science.gov (United States)

Hydraulically connected wetland microcosms vegetated with either Typha latifolia or Myriophyllum aquaticum were amended with an NH4NO3 and permethrin mixture to assess the effectiveness of both plant species in mitigating ecological effects of the pollutant mixture on phytoplankton (as chlorophyll a...

The first toxicological study of the antiozonant and research tool ethylene diurea (EDU) using a Lemna minor L. bioassay: Hints to its mode of action

International Nuclear Information System (INIS)

Agathokleous, Eugenios; Mouzaki-Paxinou, Akrivi-Chara; Saitanis, Costas J.; Paoletti, Elena; Manning, William J.

2016-01-01

The antiozonant and research tool ethylene diurea (EDU) is widely studied as a phytoprotectant against the widespread pollutant ground-surface ozone. Although it has been extensively used, its potential toxicity in the absence of ozone is unknown and its mode of action is unclear. The purpose of this research was to toxicologically assess EDU and to further investigate its mode of action using Lemna minor L. as a model organism. Application of EDU concentrations greater than 593 mg L −1 (practically 600 mg L −1 ) resulted in adverse inhibition of colony growth. As no-observed-toxic-effects concentration (NOEL) we recommend a concentration of 296 mg L −1 (practically 300 mg L −1 ). A hormetic response was detected, i.e. stimulatory effects of low EDU concentrations, which may indicate overcompensation in response to disruption in homeostasis. Growth inhibition and suppressed biomass were associated with impacted chlorophyll a fluorescence (Φ PSII , q P and ETR). Furthermore, EDU increased mesophyll thickness, as indicated by frond succulence index. Applications of concentrations ≥593 mg L −1 to uncontrolled environments should be avoided due to potential toxicity to sensitive organisms and the environment. - Highlights: • The EDU concentration of 300 mg L −1 should be considered as NOEL. • EDU concentrations ≥600 mg L −1 should not be applied to uncontrolled environments. • Hormetic responses indicate overcompensation in response to homeostasis disruption. - Ethylene diurea is not toxic to sensitive organisms when applied at low concentrations (practically < 600 mg L −1 ).

Assessment of Lemna minor (duckweed) and Corbicula fluminea (freshwater clam) as potential indicators of contaminated aquatic ecosystems: responses to presence of psychoactive drug mixtures.

Science.gov (United States)

Bourioug, Mohamed; Mazzitelli, Jean-Yves; Marty, Pierre; Budzinsky, Hélène; Aleya, Lotfi; Bonnafé, Elsa; Geret, Florence

2018-04-01

The pharmaceutical products are emerging pollutants continuously released into the environment, because they cannot be effectively removed by the wastewater treatment plants. In recent years, questions have been raised concerning the environmental risks related to these pollutants. The goal of this research was to evaluate the responses in Lemna minor after 7 days and in Corbicula fluminea after differing durations (1, 3, 7, and 19 days) of exposure to the psychoactive drug mixture (valproic acid, citalopram, carbamazepine, cyamemazine, hydroxyzine, oxazepam, norfluoxetine, lorazepam, fluoxetine, and sertraline) in different concentrations (0, 0 + ethanol, drug concentration (DC) 1 = river water concentration, DC2 = effluent concentration, and DC3 = 10× effluent concentration). In this aim, growth parameters of L. minor, gluthathione S-transferase (GSTs), catalase (CAT), ethoxyresorufin-O-deethylase (EROD) and/or gene expressions (pi-gst, cat, cytochrome P450 4 (cyp4), multidrug resistant 1 (mdr1), and superoxide dismutase (sod)) were measured. GST activities increased significantly in L. minor exposed to DC3, but no changes were found in CAT activity. In C. fluminea, EROD activity was induced significantly in both gill and digestive gland tissues after 3 days' exposure to DC3, while a GST increase was observed only in digestive gland tissues, suggesting that these pharmaceuticals induced an oxidative effect. Gene expression analysis revealed transient transcriptomic responses of cyp4, sod, and mdr1 under drug concentrations 2 or 3 and no change of expression for the other genes (cat and pi-gst) or condition (environmental drug concentration) tested. Finally, the data reported in this study represent important ecotoxicological information, confirming that this enzyme family (cyp4, sod, and mdr1) may be considered as a sensible and early indicator of exposure to drugs and emphasizing the involvement of selected genes in detoxification pathways.

The role of anthropogenic water reservoirs within the landscapes of mining areas – a case study from the western part of the Upper Silesian Coal Basin

Directory of Open Access Journals (Sweden)

Jaruchiewicz Ewelina

2014-03-01

Full Text Available A few thousand anthropogenic water reservoirs can be found in the area of the Upper Silesian Coal Basis (USCB located in southern Poland. In this paper the role of such anthropogenic lakes in the landscape of the western part of the USCB was presented and illustrated with the example of Knurów, a mining city, and its immediate surrounding area. The study of landscape changes in this area was carried out on the basis of archival and contemporary cartographic materials, historical sources, and interviews with inhabitants and direct field observations. It was found that the origin of the majority of the water reservoirs is related to hard coal, clay and sand mining. They were created primarily as a result of filling subsidence basins and post-mining excavations with water, as well as being the result of the construction of various hydro-technical facilities (settling ponds, fire protection water reservoirs, etc. In the study area the anthropogenic water reservoirs are of different sizes, shapes and durability and play different roles in the environment. Between 1884 and 2001 their number increased 25-fold, while at the same time their total surface area increased more than 8-fold. The role of the newly created water reservoirs in the landscape primarily involves the transformation of the existing terrestrial ecosystems into wetland ecosystems. The agro-forestry landscape of the late 19th century was transformed into a typically anthropogenic landscape with a dominant share of water reservoirs, settlement ponds and mining waste heaps. The most common species of plants around the water reservoirs are Phragmites australis, Typha latifolia, Ceratophyllum demersum, Elodea canadensis, Potamogeton natans, Lemna sp., Acorus calamus, Myriophyllum verticillatum, Sagittaria sagittifolia, Alisma plantago-aquatica and Glyceria aquatica. The most valuable elements of the flora include Trapa natans and Ruppia maritima, species recognized in Poland as threatened

How TK-TD and population models for aquatic macrophytes could support the risk assessment for plant protection products.

Science.gov (United States)

Hommen, Udo; Schmitt, Walter; Heine, Simon; Brock, Theo Cm; Duquesne, Sabine; Manson, Phil; Meregalli, Giovanna; Ochoa-Acuña, Hugo; van Vliet, Peter; Arts, Gertie

2016-01-01

This case study of the Society of Environmental Toxicology and Chemistry (SETAC) workshop MODELINK demonstrates the potential use of mechanistic effects models for macrophytes to extrapolate from effects of a plant protection product observed in laboratory tests to effects resulting from dynamic exposure on macrophyte populations in edge-of-field water bodies. A standard European Union (EU) risk assessment for an example herbicide based on macrophyte laboratory tests indicated risks for several exposure scenarios. Three of these scenarios are further analyzed using effect models for 2 aquatic macrophytes, the free-floating standard test species Lemna sp., and the sediment-rooted submerged additional standard test species Myriophyllum spicatum. Both models include a toxicokinetic (TK) part, describing uptake and elimination of the toxicant, a toxicodynamic (TD) part, describing the internal concentration-response function for growth inhibition, and a description of biomass growth as a function of environmental factors to allow simulating seasonal dynamics. The TK-TD models are calibrated and tested using laboratory tests, whereas the growth models were assumed to be fit for purpose based on comparisons of predictions with typical growth patterns observed in the field. For the risk assessment, biomass dynamics are predicted for the control situation and for several exposure levels. Based on specific protection goals for macrophytes, preliminary example decision criteria are suggested for evaluating the model outputs. The models refined the risk indicated by lower tier testing for 2 exposure scenarios, while confirming the risk associated for the third. Uncertainties related to the experimental and the modeling approaches and their application in the risk assessment are discussed. Based on this case study and the assumption that the models prove suitable for risk assessment once fully evaluated, we recommend that 1) ecological scenarios be developed that are also

镧、锌及其交互作用对浮萍活性氧清除系统的影响%Effect of interaction of La and Zn on the reactive oxygen scavenging system in leaves of Lemna minor

Institute of Scientific and Technical Information of China (English)

马广岳; 施国新; 王学; 徐勤松; 王贵民; Rafeek Khaled

2004-01-01

以浮萍(Lemna minor)为材料,研究La、Zn及其交互作用对体内活性氧清除系统的影响,单独施加20 mg·L-1的La或Zn对浮萍都有明显的伤害作用,且Zn的毒性远大于La.La、Zn复合处理不同程度地减弱各自的毒性,表现为植株叶绿素含量、蛋白质含量及过氧化氢酶(CAT)活性下降减缓;谷胱甘肽(GSH)、抗坏血酸(AsA)含量提高;超氧化物歧化酶(SOD)活性增强;过氧化物酶(POD)活性降低.各处理对浮萍的毒性由大到小的顺序依次为:Zn、La、Zn+La.

镉对浮萍叶绿素荧光参数的影响%Effects of cadmium stress on chlorophyll fluorescence parameters of Lemna mlnor L.

Institute of Scientific and Technical Information of China (English)

李伶; 袁琳; 宋丽娜; 顾詠洁

2010-01-01

以浮萍(Lemna minor L.)为实验材料,使用水下调制荧光仪研究不同镉浓度(0、1、2、4、6、8和10mg-L-1)条件下浮萍叶绿素荧光的变化和叶绿素含量的变化,探讨了镉对浮萍生长和光合作用的影响.结果表明,镉胁迫导致浮萍最大光化学量子产量(Fv/Fm)、光系统Ⅱ(PSⅡ)有效量子产量(φPSⅡ)、光化学淬灭(qP)、相对电子传递速率(rETR)、质体醌库(Fv/2)下降,非光化学淬灭(qN)和PSⅡ水裂解端失活程度(Fv/Fv)上升,说明浮萍的PSⅡ光合活性受到镉胁迫抑制.对浮萍叶绿素含量的测定结果表明.浮萍叶绿索含量明显下降,并且叶绿素a的下降幅度大于叶绿素b;同时,浮萍PSⅡ水裂解程度(Fo/Fv)对于镉胁迫反应极为灵敏,因而可以作为金属胁迫的重要指标.

Biological Screening of Eichornia crassipes against Different Pathogenic Microbes: An In Vitro Study

Directory of Open Access Journals (Sweden)

Rubina Rehman

2016-09-01

Full Text Available The present research is a biological screening of Eichornia crassipes (Pontederiaceae. Dichloromethane and methanol extracts of the whole plant were investigated for their antibacterial, antifungal, phytotoxic, and cytotoxic activities. The antibacterial activity was evaluated using agar well-diffusion method against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Shigella flexneri, Pseudomonas aeruginosa, and Salmonella typhi. The antifungal activity was evaluated using the agar tube–dilution method against Candida albicans, Candida glabrata, Aspergillus flavus, Microsporum canis, and Fusarium solani. The phytotoxicity activity was determined using Lemna bioassay against Lemna minor. Brine shrimp–cytotoxicity assay was determined against brine-shrimp larvae. Dichloromethane extract exhibited significant phytotoxicity (100% growth regulation at 1,000 µg/ml concentration against Lemna minor whereas methanolic extracts showed moderate (75% growth regulation phytotoxicity at the same concentration. Methanolic extract showed cytotoxicity at the highest level of dose whereas dichloromethane extract showed no activity having Etoposide as standard drug. Both of the extracts have nonsignificant antifungal and antibacterial activity.

Characterizing dose response relationships: Chronic gamma radiation in Lemna minor induces oxidative stress and altered polyploidy level

International Nuclear Information System (INIS)

Van Hoeck, Arne; Horemans, Nele; Van Hees, May; Nauts, Robin; Knapen, Dries; Vandenhove, Hildegarde; Blust, Ronny

2015-01-01

The biological effects and interactions of different radiation types in plants are still far from understood. Among different radiation types, external gamma radiation treatments have been mostly studied to assess the biological impact of radiation toxicity in organisms. Upon exposure of plants to gamma radiation, ionisation events can cause, either directly or indirectly, severe biological damage to DNA and other biomolecules. However, the biological responses and oxidative stress related mechanisms under chronic radiation conditions are poorly understood in plant systems. In the following study, it was questioned if the Lemna minor growth inhibition test is a suitable approach to also assess the radiotoxicity of this freshwater plant. Therefore, L. minor plants were continuously exposed for seven days to 12 different dose rate levels covering almost six orders of magnitude starting from 80 μGy h"−"1 up to 1.5 Gy h"−"1. Subsequently, growth, antioxidative defence system and genomic responses of L. minor plants were evaluated. Although L. minor plants could survive the exposure treatment at environmental relevant exposure conditions, higher dose rate levels induced dose dependent growth inhibitions starting from approximately 27 mGy h"−"1. A ten-percentage growth inhibition of frond area Effective Dose Rate (EDR_1_0) was estimated at 95 ± 7 mGy h"−"1, followed by 153 ± 13 mGy h"−"1 and 169 ± 12 mGy h"−"1 on fresh weight and frond number, respectively. Up to a dose rate of approximately 5 mGy h"−"1, antioxidative enzymes and metabolites remained unaffected in plants. A significant change in catalase enzyme activity was found at 27 mGy h"−"1 which was accompanied with significant increases of other antioxidative enzyme activities and shifts in ascorbate and glutathione content at higher dose rate levels, indicating an increase in oxidative stress in plants. Recent plant research hypothesized that environmental genotoxic

Effects of inorganic nitrogen compounds and pH on the growth of duckweed Lemna aequinoctialis%pH及无机氮化合物对细脉浮萍生长的影响

Institute of Scientific and Technical Information of China (English)

种云霄; 胡洪营; 钱易

2003-01-01

研究以细脉浮萍( Lemna aequinoctialis)为研究对象,在完全培养液的基础上模拟生活污水的氨氮、硝酸氮浓度和pH范围,研究了培养条件对其生长的影响.结果表明,这个浮萍种对pH耐受的低限在4～5之间,最适pH范围为5～6.非离子态的氨会对其生长产生抑制作用,在氨氮为唯一氮源的条件下,非离子态氨的浓度大于0.1mg/L时会对此种的生长产生明显的抑制作用,接近2mg/L时,基本上致死.在研究的氨氮和硝酸氮浓度范围内(<40mg N /L),铵根离子和硝酸根离子浓度增加可促进细脉浮萍的生长.氨氮中生长的植株过氧化物酶活性高于硝酸氮中的活性.

The use of artificial spawning substrates in order to understand the factors influencing the spawning site selection, depth of egg strands deposition and hatching time of perch (Perca fluviatilis L.)

Czech Academy of Sciences Publication Activity Database

Čech, Martin; Vejřík, L.; Peterka, Jiří; Říha, Milan; Muška, Milan; Jůza, Tomáš; Draštík, Vladislav; Kratochvíl, Michal; Kubečka, Jan

2012-01-01

Roč. 71, č. 1 (2012), s. 170-179 ISSN 1129-5767 R&D Projects: GA ČR(CZ) GP206/09/P266 Institutional support: RVO:60077344 Keywords : SCUBA diving * aquatic vegetation * lake management * common stonewort Chara vulgaris * Eurasian water milfoil Myriophyllum spicatum Subject RIV: EG - Zoology Impact factor: 1.473, year: 2012

Economic Potentialities of Some Aquatic Plants Growing in North East Nile Delta, Egypt

Science.gov (United States)

Abu Ziada, M. E.; Mashaly, I. A.; Abd El-Monem, M.; Torky, M.

The present study provides quantitative assessment of the vegetative yield, growth characteristics, metabolic products, elemental composition and antimicrobial bioactivity of five common macrohydrophytes: Bolboschoenus glaucus (Cyperaceae), Veronica anagallis-aquatica (Scrophulariaceae), Nymphaea lotus (Nymphaceae), Pistia stratiotes (Araceae) and Myriophyllum spicatum (Haloragidaceae). These plants tend to flourish vegetatively during the summer season (June-August). Their relative growth rate, relative assimilating surface growth rate and net assimilation rate were higher during early vegetative stage (February-May). The highest percentages of protein and lipids content were recorded in Nymphaea, while the crude fiber content was higher in Bolboschoenus than in other species. The macronutrient elements were detected with relatively high concentration and sodium cation appeared to be an essential accumulatent as compared with K, Ca and Mg. Myriophyllum appeared to be the major accumulator species of heavy metals, while Pistia appeared to be the minor one. Sterols, alkaloids, flavonoids, tannins, saponins and resins were detected in these plants. Nymphyaea was found to have the most effective antimicrobial activities than the other studied species.

Adiciones a las haloragaceae de Colombia: Proserpinaca palustris

Directory of Open Access Journals (Sweden)

Schmidt Mumm Udo

2000-07-01

Full Text Available Las especies colombianas de la familia Haloragaceae se han asignado a dos subfamilias y tres géneros. Según Mora-Osejo (1984, quién comparte la opinión de Schindler (1905 en incluir el género Gunnera L. en la sub familia terrestre Gunneroideae, la sub familia Haloragoideae distingue las plantas acuáticas y semiacuáticas de tallos herbáceos, raras veces subleñosos, hojas opuestas o verticiladas e inflorescencias terminales. Inicialmente se designaron dos especies del género Myriophyllum L. a esta subfamilia y poco después se señaló también el hallazgo del género Laurembergia Berg. (Mora-Osejo et al. 1988. En la actualidad, sin embargo, se ha generalizado la tendencia a considerar el género Gunnera separadamente en la familia Gunneraceae (Cronquist 1988, L. E. Mora-Osejo, como pers., con lo cual las Haloragaceae de Colombia se encuentran representadas por tres especies de los géneros Myriophyllum y Laurembergia.

Optimización de un método analítico para la determinación de mercurio en muestras ambientales por espectrometría UV-Visible

Directory of Open Access Journals (Sweden)

Xiomara Piña

2012-12-01

Full Text Available Dithizone´s colorimetric method was modified and quasi miniaturized for mercury determination in water and Lemna minor and Piaractus brachypomus tissue. Detection limit (4-22µg.L-1 was adequate for environmental studies. Evaluation of the accuracy in water was achieved by analyzing SPEX CERTIPREP standard samples with no significant differences. 85-120% recovery percentages for digested biota were obtained. The precision was less than 10% of relative standard deviation in all the cases. The method is reliable for mercury determination in water, red-bellied and Lemna minor tissue.

Detection of stable isotopes with a (n, α) nuclear reaction: application to the measurement of unidirectional fluxes of borate in a plant

International Nuclear Information System (INIS)

Duval, Y.; Thellier, M.; Heurteaux, C.; Wissocq, J.C.

1980-01-01

The unidirectional influx of borate has been studied in Lemna minor plants with the aid of purified boron isotopes, 10 B and 11 B. Isotope 10 B was detected specifically by nuclear reaction 10 B(n, α) 7 Li in the presence of ''homogeneous'' detectors. Despite technical difficulties in performing the 10 B-estimations in the plant samples themselves, the results obtained here were consistent with those of efflux experiments, published previously, where the 10 B-measurements were performed in the external solution. Kinetic parameters of borate transports in Lemna minor have been calculated. (author)

Valorização biotecnológica de Landoltia punctata com vistas a uma produção de etanol

OpenAIRE

Souto, Luciana Reis Fontinelle

2016-01-01

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Alimentos, Florianópolis, 2016. A lemna tem sido apontada como uma biomassa potencial para a produção de etanol, devido a sua capacidade de acumular amido, possuir altas velocidades de crescimento, baixo teor de lignina, dentre outras características. Neste trabalho a produção de etanol a partir da biomassa de lemna (Landoltia punctata) foi avaliada. O estudo foi dividi...

典型温带季风地区浮萍科植物遗传多样性%Genetic Diversity of Duckweed in a Typical Temperate and Monsoon Region

Institute of Scientific and Technical Information of China (English)

张震宇; 韩冰莹; 孙雪飘; 付莉莉; 叶松建; 张家明

2018-01-01

Jilin Province is a typical temperate monsoon region,its duckweed bioresources contain different characteristics compared with tropical and subtropical regions in China.In total,41 accessions of duckweeds were collected in Jilin Province.Through morphological classification and molecular identification based on chloroplast atpF-atpH spacer sequences and rpSl6 intron sequences,these accessions were identified as Spirodela and Lemna,including Spirodela polyrhiza,Lemna perpusilla,Lemna turionifera,and Lemna aequinoctialis.There is only one accession in L.aequinoctialis,while accessions ofS.polyrhiza,L.perpusilla,and L.turionifera are 12,13,and 15,respectively.Genetic diversity analysis showed that the indexes of the nucleotide diversity in atpF-atpH and rpS16 were 0.034 04 and 0.065 31,respectively.The nucleotide difference per kb were 21.446 and 60.544,and the haplotype diversity were 0.696 and 0.750,respectively.Wolffia and Landoltia were not collected in Jilin Province,and the distribution of L.aequinoc tialis was far less than duckweed species distributed in southern China,indicating small genetic diversity.The study would provide the molecular basis for species identification and interspecific relationship analysis of duckweed and benefit future botanical studies of duckweeds in North-Eastern China and other temperate monsoon zones.%吉林省为典型温带季风地区,其浮萍科植物资源具有与中国热带、亚热带地区不同的特点.在吉林省各地共收集到41份浮萍种质资源,通过形态学分类和基于叶绿体atp F-atpH间隔序列和rpS16内含子序列的分子生物学鉴定,这些种质分别属于紫萍属(Spirodela)和青萍属(Lemna),共有Spirodela polyrhiza、Lemna perpusilla、Lemna turionifera、Lemna aequinoctidis等4个物种.除L.aequinoctialis仅发现一份种质外,其余三种分布较为均等,其中S.polyrhiza、L.perpusilla、L.turionifera分别有12、13、15�

Preliminary Guide to the Onsite Identification and Delineation of the Wetlands of the South Atlantic United States.

Science.gov (United States)

1982-05-01

shield) Ceratophyilum demersum (Coontail) Myriophyllum spp. (Watermilfoil) Nelumbo lutea ( American lotus) Nuphar luteum (Spatterdock) Nymphaea odorata...Overcup oak) Quercus palustris (Pin oak) Quercus phelios (Willow oak) Ulmus americana ( American elm) UlmuS rubra (Slippery elm) c. Atlantic White...var. biflora (Swamp black gum) Persea borbonia (Red bay) Pinus serotina (Pond pine) Smilax laurifolia (Bamboo vine) Sphagnum spp. (Sphagnum moss

Effects of light and temperature on duckweed photosynthesis

Energy Technology Data Exchange (ETDEWEB)

Wedge, R M; Burris, J E

1982-06-01

Rates of photosynthesis of Lemna minor L. and Spirodela punctata, two aquatic angiosperms, were measured at different temperatures and light intensities. Photosynthesis was measured both as oxygen evolution and /sup 14/CO/sub 2/ fixation. At temperatures ranging from 15 to 35/sup 0/C, light saturation of photosynthetic O/sub 2/ evolution of Lemna occured from 300-600 ..mu..E m/sup -2/ s/sup -1/, while in Spirodela photosynthetic O/sub 2/ evolution was light saturated at 5600-1200 ..mu..E m/sup -2/ s/sup -1/. Photosynthetic O/sub 2/ evolution of both species was photoinhibited at light intensities greater than 1200 ..mu..E m/sup -2/ s/sup -1/. The optimal temperature for Lemna photosynthetic O/sub 2/ evolution was 30/sup 0/C, while the optimal temperatures for /sup 14/CO/sub 2/ fixation were from 20 to 30/sup 0/C. For Spirodela maximum photosynthetic O/sub 2/, evolution occurred at 35/sup 0/C, while maximum /sup 14/CO/sub 2/ fixation was at 30/sup 0/C.

Absorption and degradation of 14C-2, 4-D by some free-floating aquatic weeds

International Nuclear Information System (INIS)

Singh, S.P.

1980-01-01

Plants of Salvinia, Lemna, Azolla and Limnobium, which are free-floating aquatic weeds, were grown separately in glass dishes containing initially 400 ml of nutrient solution and 2 μCi of 14 C-2,4-D under controlled conditions of temperature, light and relative humidity. The total uptake of 2,4-D by these plant species increased with the increasing duration of exposure to herbicide. 2,4-D uptake, calculated on per unit dry weight of weed, was maximum in case of Limnobium, followed by Salvinia, Lemna and Azolla. After 20 days of treatment, the highest radioactivity (24%) was obtained in the organic fraction of the extracts of Limnobium and Azolla; followed by Salvinia (8%) and Lemna (6%). In a separate experiment, root uptake and subsequent translocation of 14 C-2,4-D was also studied. At all the stages of sampling, more than half to 3/4th of the absorbed 14 C-2,4-D was found in the roots, and the remaining was present in the shoot. (author)

UV-B辐射和蒽共同作用对三叶浮萍的毒性效应%Joint Toxic Effects of UV-B Radiation and Anthracene on Lemna Minor

Institute of Scientific and Technical Information of China (English)

张攀; 王仁君; 周晶; 沙未来

2012-01-01

本实验采用常见的三叶浮萍作为实验材料,研究了多环芳烃( PAHs)蒽(Anthracene)与UV-B辐射单独胁迫和共同作用对浮萍(Lemna minor)的毒性效应.浮萍的初始个数为45个,蒽的质量浓度分别设为0、0.5、2.5、5、10、20mg·L-1,设计三个个平行组,每组辐射剂量均是810 J·m-2.结果表明,蒽、紫外线单独胁迫都会对浮萍产生损害,使其生长量有下降趋势.当辐射剂量达到810 J·m-2时,叶绿素含量达到最大,随着辐射剂量的增加,叶绿素含量减少.且随着蒽浓度的不断增大,对浮萍生长的其抑制作用更加明显,存在着明显的剂量-效应关系.蒽和UV-B辐射共同作用对浮萍产生抑制作用,并且随着蒽浓度的增加,抑制作用逐渐增强.

On the variability of plant bio-concentration factors (BCF) of environmental radionuclides. A case study on the effects of surface film and free space on the interpretation of 99mTcO4- sorption in duckweed

International Nuclear Information System (INIS)

Wolterbeek, H.T.; Van der Meer, A.J.G.M.; Dielemans, U.

2000-01-01

The present paper addresses plant bioaccumulation factor (BCF) variability, and specifically focuses attention upon the handling of duckweed (Lemna gibba) material, sampled from experimental media, especially considering accumulation/kinetic studies with 99mTcO 4 - . In these short-term studies, relatively small BCF-values may be encountered, with related interferences in its assessment due to the presence of 99mTcO 4 - in the surface film medium (SF) and in the cellular water free spaces (FS). The sample handling methods used to remove the SF+FS component of the accumulated 99mTcO 4 - consisted of blotting, centrifugation and rinsing. The three methods were investigated using d-[1- 14 C]mannitol, 42K + , 82Br - and 99mTcO 4 - radioisotopes, which were measured by - and γ-spectrometry, in both solution and solid samples. Centrifugation seems the most promising method to remove SF+FS 99mTcO 4 - . Results based on both mass analysis and radioactivity determinations in centrifugated fluids are independent of applied concentrations (10 -11 to 10 -3 mol m -3 99mTcO 4 - ), and are invariably compatible with the conceptual idea of the FS as a free-entrance phase for solutes. Blotting results in an overestimation of BCF values (up to factor 3 for the 99mTcO 4 - experiments performed), probably due to the incomplete removal of the SF+FS, and is suggested to yield irregular results, leading to high variances in BCF values obtained. The application of an efflux/rinsing period is indicated to result in an underestimation of BCF values (up to factor 10 for the 99mTcO 4 - experiments performed), probably due to excess removal of (non-SF+FS) components of accumulated solutes. Here we advocate centrifugation as a routine sample handling method to avoid SF+FS interferences in short-term (kinetic) 99mTcO 4 - uptake studies in duckweed. Moreover, the results suggest a more general applicability of centrifugation as a sample handling method to avoid SF+FS interferences in short

Detection of stable isotopes with a (n,. cap alpha. ) nuclear reaction: application to the measurement of unidirectional fluxes of borate in a plant

Energy Technology Data Exchange (ETDEWEB)

Duval, Y; Thellier, M; Heurteaux, C; Wissocq, J C [Centre National de la Recherche Scientifique, Mont-Saint-Aignan (France). Lab. ' ' Echanges cellulaires' '

1980-01-01

The unidirectional influx of borate has been studied in Lemna minor plants with the aid of purified boron isotopes, /sup 10/B and /sup 11/B. Isotope /sup 10/B was detected specifically by nuclear reaction /sup 10/B(n, ..cap alpha..)/sup 7/Li in the presence of ''homogeneous'' detectors. Despite technical difficulties in performing the /sup 10/B-estimations in the plant samples themselves, the results obtained here were consistent with those of efflux experiments, published previously, where the /sup 10/B-measurements were performed in the external solution. Kinetic parameters of borate transports in Lemna minor have been calculated.

Process for sewage biological treatment from uranium

International Nuclear Information System (INIS)

Popa, K.; Cecal, A.; Craciun, I.

2004-01-01

The invention relates to the sewage treatment, in particular to the sewage biological treatmen from radioactive waste, namely from uranium. The process dor sewage biological treatment from uranium includes cultivation in the sewage of the aquatic plants Lemna minor and Spirulina platensis. The plants cultivation is carried out in two stages. In the first stage for cultivation is used Lemna minor in the second stage - Spirulina platensis . After finishing the plant cultivation it is carried out separation of their biomass. The result of the invention consists in increasing the uranyl ions by the biomass of plants cultivated in the sewage

Process for sewage biological treatment from uranium

International Nuclear Information System (INIS)

Popa, Karin; Cecal, Alexandru; Craciun, Iftimie Ionel; Rudic, Valeriu; Gulea, Aurelian; Cepoi, Liliana

2004-01-01

The invention relates to the sewage treatment, in particular to the sewage biological treatment from radioactive waste, namely from uranium. The process for sewage biological treatment from uranium includes cultivation in the sewage of the aquatic plants Lemna minor and Spirulina platensis. The plant cultivation is carried out in two stages. In the first stage for cultivation is used Lemna minor and in the second stage - Spirulina platensis. After finishing the plant cultivation it is carried out separation of their biomass. The result of the invention consists in increasing the uranyl ions accumulation by the biomass of plants cultivated in the sewage.

利用稻田养萍诱集控制福寿螺危害的效应研究%Decoy effect of duckweed Lemna minor on Pomacea canaliculata in rice from paddy fields

Institute of Scientific and Technical Information of China (English)

郭靖; 章家恩; 张春霞; 项瑶

2016-01-01

利用自制的“T形槽”进行实验室试验,研究了福寿螺(Pomacea canaliculata)对浮萍(Lemna minor)和不同日龄水稻(Oryza sativa)的偏好选择,结果发现,无论水稻日龄是15d,还是23 d和30 d,均有60％以上的福寿螺选择取食浮萍,且与福寿螺个体大小和选择取食的时间没有明显关联.在模拟稻田生境中,引入浮萍3d后,水稻受福寿螺的啃食危害明显减少,水稻存活率高出对照组10％以上,且30日龄水稻秧苗的存活率明显高于15日龄处理.在此基础上,分析了不同大小福寿螺与浮萍摄入量的关系.这一结果可为浮萍的合理投放提供参考.研究表明,利用稻田放养浮萍诱集福寿螺取食,可以减少福寿螺对水稻的危害.

Land spreading of sewage sludge in forest plantations: effects on the growth of the duckweed Lemna minor and trace metal bioaccumulation in the snail Cantareus aspersus.

Science.gov (United States)

Mohamed, Bourioug; Frédéric, Gimbert; Laurence, Alaoui-Sehmer; Pierre-Marie, Badot; Badr, Alaoui-Sossé; Lotfi, Aleya

2016-05-01

Wastewater plants generated annually millions of tons of sewage sludge (SS). Large amounts of this organic residue are spread on agricultural lands as a fertilizer, although it is viewed as a major potential source of contamination, presenting a danger to the terrestrial and aquatic environments. This study was undertaken to evaluate the impact of this practice on the duckweed Lemna minor and the snail Cantareus aspersus. Sludge was applied to soil either at six different loading rates equal to 0, 0.4, 3, 10, 30, and 60 tons dry matter (DM) ha(-1) for L. minor test or at three rates equal to 0, 30, and 60 tons DM ha(-1) for C. aspersus test. At the highest rate of SS application (60 tons DM ha(-1)), the eluates showed that an increase in pH (6.1) resulted in a decrease in Al levels. Thus, the high stimulation of L. minor growth observed after this high rate of SS application can be explained by (i) a reduction in Al toxicity after precipitation and (ii) macro- and micronutrient enrichment. At a rate of SS application of only 30 tons DM ha(-1), growth appeared to be slightly significant (p < 0.05), in spite of the significant increase in essential mineral elements. However, it is very difficult to discriminate between Al toxicity and pH effects. For the test with C. aspersus, the snail biomass was not affected by sludge application over the exposure period. Mortality was extremely low, with a rate of less than 4 % at the last sampling date. Yet, Cu, Pb, and Cd accumulated significantly in the soft body of snails exposed to SS application, suggesting that the amount of metals excreted is lower than that absorbed. In contrast, Zn levels remain constant, inferring that absorption and elimination of Zn are balanced at the beginning of the experiment.

THE INFLUENCE OF CADMIUM CHLORIDE ON FATTY ACID COMPOSITION OF HIGH AQUATIC PLANTS FROM ANGARA RIVER

Directory of Open Access Journals (Sweden)

Kirichenko K.A.

2011-03-01

Full Text Available The comparative analysis of the fatty acid content in Myriophyllum spicatum L. and Elodea canadensis Michx. has been carried out during 24 hours of the treatment with 0,05 M cadmium chloride. Changes in a fatty acids composition in response to toxic influence have been shown. The differences in change dynamics of the fatty acids content under the treatment with cadmium chloride have been detected in investigated species.

Aportaciones a la flora de Galicia, VIII

OpenAIRE

Gómez Vigide, F.; García Martínez, X.R.; Silva Pando, F.J.; González Domínguez, J.; Blanco Dios, J.B.; Rodríguez González, A.; Rial Pousa, S.; Álvarez Graña, D.; Caamaño Portela, J.L.; Pino Pérez, J.J.; Pino Pérez, R.

2006-01-01

Se citan 37 plantas de variado interés para la flora gallega. Se incluyen 8 novedades de carácter regional (Pteris incompleta Cav., Potentilla recta L., Myriophyllum spicatum L., Solanum sisymbrifolium Lam., Knautia integrifolia (L.) Bertol., Senecio inaequidens DC. Melica arrecta G. Kunze y Stipa clausa Trab.), 17 novedades provinciales (Vandenboschia speciosa (Willd.) G. Kunkel, Ranunculus bupleuroides Brot., Silene niceensis All., Armeria transmontana (Samp.) Lawr., Alcea rosea...

非离子型表面活性剂AE对稀脉浮萍的损伤作用%STUDY ON THE INJURIES OF LEMNA PAUCICOSTATA L.　DUE TO NONIONIC SURFACTANT LINEAR ALKYLETHOXYLATE(AE)

Institute of Scientific and Technical Information of China (English)

刘红玉; 周朴华; 杨仁斌; 廖柏寒; 鲁双庆

2001-01-01

以过氧化氢酶(CAT)、过氧化物酶(POD)相对活性、植物生长量和培养液pH值变化作为观测指标，研究了非离子型表面活性剂脂肪醇聚氧乙烯醚（AE）对稀脉浮萍（Lemna paucicostata L.）的损伤作用.结果显示：稀脉浮萍的损伤程度与AE浓度直接相关.浓度小于1.0 mg/L时，AE对稀脉浮萍的损伤较轻，λ（CAT）、λ（POD）的增加，能清除膜上的过氧化物；在10.0 mg/L时，稀脉浮萍的生理功能受到中等程度的伤害.CAT、POD相对活性升高，生长率下降，光合作用受到一定程度的抑制，培养液pH值下降0.2左右；AE为100.0 mg/L时，植物受伤严重，CAT、POD相对活性下降，培养液pH值降低幅度为0.6左右，植物大部分死亡. 图6 参12

Bioleaching of UO22+ ions from a Romanian poor uranium ore

International Nuclear Information System (INIS)

Cecal, Al.; Popa, K.; Moraru, R.T.; Patachia, S.

2002-01-01

An experimental study on the bioleaching of a poor uranium ore by means of hydrophytic plants Lemna minor and Riccia fluitans, under various operating conditions is discussed. The maximum degree of bioleaching (42%) of the reduced uranium species to U(VI) has been attained for the ore-Lemna minor-alkaline carbonate solution system. The UO 2 2+ ions amount accumulated in the plants is negligible as compared to the dissolved quantity, owing to the ionic competition between uranyl ions and the cations necessary to the mineral nutrition. The X-ray diffraction patterns prove that the uranium species in pyrochlore mineral are completely oxidized to U(VI), while thucolite is only partially turned into UO 2 2+ ions, in the presence of living plants. (author)

Unicellular cyanobacteria with a new mode of life: the lack of photosynthetic oxygen evolution allows nitrogen fixation to proceed.

Science.gov (United States)

Bothe, Hermann; Tripp, H James; Zehr, Jonathan P

2010-10-01

Some unicellular N(2)-fixing cyanobacteria have recently been found to lack a functional photosystem II of photosynthesis. Such organisms, provisionally termed UCYN-A, of the oceanic picoplanktion are major contributors to the global marine N-input by N(2)-fixation. Since their photosystem II is inactive, they can perform N(2)-fixation during the day. UCYN-A organisms cannot be cultivated as yet. Their genomic analysis indicates that they lack genes coding for enzymes of the Calvin cycle, the tricarboxylic acid cycle and for the biosynthesis of several amino acids. The carbon source in the ocean that allows them to thrive in such high abundance has not been identified. Their genomic analysis implies that they metabolize organic carbon by a new mode of life. These unicellular N(2)-fixing cyanobacteria of the oceanic picoplankton are evolutionarily related to spheroid bodies present in diatoms of the family Epithemiaceae, such as Rhopalodia gibba. More recently, spheroid bodies were ultimately proven to be related to cyanobacteria and to express nitrogenase. They have been reported to be completely inactive in all photosynthetic reactions despite the presence of thylakoids. Sequence data show that R. gibba and its spheroid bodies are an evolutionarily young symbiosis that might serve as a model system to unravel early events in the evolution of chloroplasts. The cell metabolism of UCYN-A and the spheroid bodies may be related to that of the acetate photoassimilating green alga Chlamydobotrys.

不同浓度养殖废水对青萍生长能力的影响%Influence of livestock wastewater concentration on growth of common duckweed (Lemna minor)

Institute of Scientific and Technical Information of China (English)

顾新娇; 杨闯; 王文国; 汤晓玉; 胡启春

2015-01-01

为了探讨废水浓度对青萍(Lemna minor)净化能力、生物质和能量积累能力的影响,以猪场养殖废水为供试废水,分析了在不同废水浓度下青萍对废水中总氮(TN)、氨氮和总磷(TP)的净化能力,青萍的生长情况,以及青萍中碳(C)、氮(N)、磷(P)元素含量和热值的变化情况.研究表明,青萍在1％浓度的废水中表现出最高的污染物净化能力.虽然青萍的C、N、P含量和热值均随废水浓度的增加而增加,但是由于相对增长率以1％的废水中生长的青萍最高,青萍的最高生产力、C和能量的固定能力均出现在1％废水浓度培养的青萍中,其次是5％废水浓度培养的青萍.多项式回归分析表明,可以使青萍获得最大C和能量固定能力的废水浓度为3.4％,对应的氨氮浓度为26 mg./L,TP浓度为3.4 mg/L.研究结果为进一步优化高生物质生产、高污染物去除率的养殖废水-浮萍培养体系提供了一定的基础.

Antimicrobial, Cytotoxic and Phytotoxic Potency of Ethyl Acetate ...

African Journals Online (AJOL)

The antifungal activity was determined by inhibitory effect on the growth of. Alternaria ... Results: The extract showed phytotoxic activity (at 95% level of significance) against Lemna minor ..... screening of various organic extracts of caesalpinia.

The Study on Effect of Hg,Cd and Their Combined Pollution in Leaves of Lemna minor L.%Hg、Cd及其复合污染对浮萍叶片的毒害研究

Institute of Scientific and Technical Information of China (English)

徐楠; 施国新; 杜开和; 张小兰; 曾晓敏; 周红卫

2002-01-01

研究了不同浓度Hg、Cd及其复合污染对浮萍(Lemna minor L.)叶片生理生化以及超微结构的毒害影响.经观察分析,培养4d后各处理组均呈现出不同程度的受害症状.随处理浓度的递增,叶绿素含量以及可溶性蛋白含量明显下降;抗氧化酶系统活性及脯氨酸含量均表现出一显著抗性峰,而后下降.通过电镜观察发现,叶绿体膨胀,外膜破裂,基粒片层垛叠混乱;线粒体脊突膨胀,呈现凌乱状态甚至空泡状残体;细胞核变形,核膜内陷,染色质凝集,呈无序状态甚至解体.结果表明:Cd对浮萍叶细胞的毒性比Hg大,Hg、Cd复合污染呈现明显的协同作用,加强了对叶细胞的伤害.Hg对于浮萍叶片的致死浓度在5～7mg/L之间;Cd的致死浓度在2.5～5mg/L之间;Hg+Cd的致死浓度在1mg/L Hg+1mg/L Cd～2.5mg/L Hg+2.5mg/LCd 之间.

Полисахариды из каллусной культуры Lemna minor L

OpenAIRE

Гюнтер, Е.

2001-01-01

Целью настоящей работы была общая химическая характеристика полисахаридов, выделенных из каллусной культуры Lemna minor L. Полисахариды каллуса L. minor представляют собой нейтральный и кислый арабиногалактаны, пектин. В состав углеводной цепи пектина входят остатки галактуроновой кислоты (66%), арабинозы и галактозы в качестве основных компонентов....

Ash characteristics and plant nutrients in some aquatic biomasses

Science.gov (United States)

Masto, Reginald; Pandit, Ankita; George, Joshy; Mukhopadhyay, Sangeeta; Selvi, Vetrivel; Ram, Lal

2016-04-01

Aquatic biomasses are explored as potential fuel source for direct combustion because of their faster growth and no land requirement. The energy density and the ash characteristics of the aquatic biomasses are to be evaluated for their suitability for energy extraction. In the study, four aquatic plant samples namely Eichornia crassipes, Hydrilla verticilleta, Lemna minor, Spirogyra spp were collected from a pond in Digwadih Campus of Central Institute of Mining and Fuel Research, Dhanbad. The biomasses were air dried, powdered and ashed at different temperatures. Volatile C was relatively lower in Spirogyra and Hydrilla (53 %) than Eichornia (62.6 %) or Lemna (59.7 %), whereas fixed C was higher for Eichornia and Lemna (about 10 %) and lower for Hydrilla (1 %). Ultimate analysis showed that the carbon content was in the order Eichornia > Lemna > Spirogyra > Hydrilla. The IR spectra of each raw biomass is compared to their respective ashes obtained at different temperatures (500-900°C). With increase in ashing temperature from 500-900°C there is gradual breakdown of the cellulosic structure hence, peaks around 2900-2800cm-1 caused by aliphatic C-H vibration tends to disappear slowly in ash. More number of peaks appears at lower wavenumbers in ashes of all the biomass samples indicating towards increased percentage of inorganic ion species. Considerable enrichment of SiO2 is validated with prominent peaks at 1100-900 cm-1 in all the ashes. Lemna and Spirogyra has a similar ash composition (Si > Al > Ca > K), whereas, Ca was higher in Hydrilla (Si > Ca > K > Al). Eichornia (Si > K > Ca > Al) has higher K and Ca than Al. SiO2 and Al2O3 were higher in Spirogyra, while SiO2 and CaO in Eichornia and Hydrilla. K first increased from 500-700/800⁰C, and then decreased from 800-900⁰C. Cl is lost slowly in ash from 500-700/800⁰C and then by a drastic reduction from 800-900⁰C. S is enhanced in ash at all temperatures although the change is quite small. Most of the Cl

Seasonal biodiversity and ecological studies on the epiphytic microalgae communities in polluted and unpolluted aquatic ecosystem at Assiut, Egypt

Directory of Open Access Journals (Sweden)

Adam Mahmoud S.

2017-12-01

Full Text Available A qualitative and quantitative study on epiphytic microalgae was carried out seasonally from November 2015 to August 2016 to follow up their community structures on aquatic macrophytes related to some physico-chemical properties of two polluted and unpolluted water bodies at Assiut, Egypt. A total of 169 species related to 64 genera of epiphytic microalgae were recorded. The most dominant algal group was Bacillariophyceae (43.2%, followed by Chlorophyceae (34.91%, Cyanophyceae (20.71% and Euglenophyceae (1.18%. The total number of epiphytic algae fluctuated between 11.1 × 104 ind.g-1 plant dry wt. on Phragmites australis in summer at Nazlet Abdellah (polluted site and 10.02 × 107 ind.g-1 plant dry wt. on Myriophyllum spicatum in winter at El-Wasta (unpolluted site. Some epiphytic microalgae were dominant as Pseudanabaena limnetica, Calothrix braunii, Scenedesmus acutus, and Ulnaria ulna. Others were specific on certain macrophytes as Aphanocapsa thermalis and Ulothrix sp., which grow on Phragmites australis, while Synechocystis minuscula attached itself on Myriophyllum spicatum. Analysis of PERMANOVA showed that the most important factors that induced the variation in epiphytic microalgae were the temporal variation and host plant. Water temperature, pH, nitrate, chloride, phosphate and total dissolved salts were the highest abiotic factors correlated with the variation in composition of epiphytic microalgae.

Environmental Transport and Fate Process Descriptors for Propellant Compounds

Science.gov (United States)

2006-06-01

rate of 1.2 mL/min. The RP-HPLC used a mercury lamp UV detector at 254 nm. The calibration range was 0.2 to 19.2 parts per million with a reporting... phytoremediation of perchlorate- contaminated water. In Perchlorate in the environment, ed. E. T. Urbansky, 219- 229. New York, NY: Kluwer Academic/Plenum...identification of metabolic products in Myriophyllum aquaticum. International Journal of Phytoremediation 1:97-107. Swann, R. L., D. A. Laskowski, P. J. McCall

Genetic diversity and geographic differentiation analysis of duckweed using inter-simple sequence repeat markers.

Science.gov (United States)

Xue, Huiling; Xiao, Yao; Jin, Yanling; Li, Xinbo; Fang, Yang; Zhao, Hai; Zhao, Yun; Guan, Jiafa

2012-01-01

Duckweed, with rapid growth rate and high starch content, is a new alternate feedstock for bioethanol production. The genetic diversity among 27 duckweed populations of seven species in genus Lemna and Spirodela from China and Vietnam was analyzed by ISSR-PCR. Eight ISSR primers generating a reproducible amplification banding pattern had been screened. 89 polymorphic bands were scored out of the 92 banding patterns of 16 Lemna populations, accounting for 96.74% of the polymorphism. 98 polymorphic bands of 11 Spirodela populations were scored out of 99 banding patterns, and the polymorphism was 98.43%. The genetic distance of Lemna varied from 0.127 to 0.784, and from 0.138 to 0.902 for Spirodela, which indicated a high level of genetic variation among the populations studied. The unweighted pair group method with arithmetic average (UPGMA) cluster analysis corresponded well with the genetic distance. Populations from Sichuan China grouped together and so did the populations from Vietnam, which illuminated populations collected from the same region clustered into one group. Especially, the only one population from Tibet was included in subgroup A2 alone. Clustering analysis indicated that the geographic differentiation of collected sites correlated closely with the genetic differentiation of duckweeds. The results suggested that geographic differentiation had great influence on genetic diversity of duckweed in China and Vietnam at the regional scale. This study provided primary guidelines for collection, conservation, characterization of duckweed resources for bioethanol production etc.

Assessment of acrylamide toxicity using a battery of standardised bioassays.

Science.gov (United States)

Zovko, Mira; Vidaković-Cifrek, Željka; Cvetković, Želimira; Bošnir, Jasna; Šikić, Sandra

2015-12-01

Acrylamide is a monomer widely used as an intermediate in the production of organic chemicals, e.g. polyacrylamides (PAMs). Since PAMs are low cost chemicals with applications in various industries and waste- and drinking water treatment, a certain amount of non-polymerised acrylamide is expected to end up in waterways. PAMs are non-toxic but acrylamide induces neurotoxic effects in humans and genotoxic, reproductive, and carcinogenic effects in laboratory animals. In order to evaluate the effect of acrylamide on freshwater organisms, bioassays were conducted on four species: algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata, duckweed Lemna minor and water flea Daphnia magna according to ISO (International Organization for Standardisation) standardised methods. This approach ensures the evaluation of acrylamide toxicity on organisms with different levels of organisation and the comparability of results, and it examines the value of using a battery of low-cost standardised bioassays in the monitoring of pollution and contamination of aquatic ecosystems. These results showed that EC50 values were lower for Desmodesmus subspicatus and Pseudokirchneriella subcapitata than for Daphnia magna and Lemna minor, which suggests an increased sensitivity of algae to acrylamide. According to the toxic unit approach, the values estimated by the Lemna minor and Daphnia magna bioassays, classify acrylamide as slightly toxic (TU=0-1; Class 1). The results obtained from algal bioassays (Desmodesmus subspicatus and Pseudokirchneriella subcapitata) revealed the toxic effect of acrylamide (TU=1-10; Class 2) on these organisms.

Industrial wastewater treatment using higher aquatic vegetation in the former mining company of the Far Eastern Federal district

Science.gov (United States)

Krupskaya, L. T.; Zvereva, V. P.; Gula, K. E.; Gul', L. P.; Golubev, D. A.; Filatova, M. Yu.

2017-09-01

The article describes the results of studying the problems of industrial wastewater treatment using higher aquatic vegetation (hydrophytes) in the former mining enterprise of the Far Eastern Federal District (FEFD). They are aimed at reducing the negative environment impact of toxic tin ore wastes. The material of research were drainage, mine and slime waters as well as Lemna minor and Common reed grass (Phragmites communis). In the work conventional modern physico-chemical, chemical, biological and mathematical-statistical methods were used, as well as in the process of research the methods of atomic absorption spectrophotometry for AAS and mass spectrometry with inductively coupled plasma on ISP-MS ELASN DRS II PerkinElmer was applied. The data obtained in the course of the experiment (2015-2016), indicate that a degree of wastewater treatment, using Lemna minor, is high. Virtually, all compounds of toxic chemical elements contained in industrial wastewater (zinc, cobalt, nickel, cadmium, iron, manganese, lead, etc.) were fully absorbed by a hydrophyte. Pollutant extraction was almost 95%. The obtained results of the study in laboratory conditions proved the possibility of effective use of the Lemna minor for the purification of drainage and mine waters. A key contribution of this paper is the relationship between possible toxic metals contained in industrial wastewater and a higher degree of absorption by their higher aquatic vegetation. These hydrophytes absorb these possible toxic metals in an aqueous medium and are contaminated with these heavy metals.

New phytotoxic diterpenoids from Vellozia gigantea (Velloziaceae), an endemic neotropical plant living in the endangered Brazilian biome Rupestrian grasslands

Science.gov (United States)

Vellozia gigantea is a rare, ancient and endemic neotropical plant present in the Brazilian Rupestrian grasslands. The dichloromethane extract of V. gigantea adventitious roots was phytotoxic against Lactuca sativa, Agrostis stolonifera and Lemna paucicostata, and showed larvicidal activity against ...

The occurrence of hormesis in plants and algae

DEFF Research Database (Denmark)

Cedergreen, Nina; Streibig, Jens Carl; Kudsk, Per

2007-01-01

This paper evaluated the frequency, magnitude and dose/concentration range of hormesis in four species: The aquatic plant Lemna minor, the micro-alga Pseudokirchneriella subcapitata and the two terrestrial plants Tripleurospermum inodorum and Stellaria media exposed to nine herbicides and one...

浮萍生物富集洛克沙胂与阿散酸的动力学特性研究%Researches on the Kinetic Characteristics of Bioconcentration of Roxarsone and Arsanilic Acid in Duckweed (Lemna minor L.)

Institute of Scientific and Technical Information of China (English)

王付民; 张璐; 陈杖榴

2007-01-01

通过静态法和半静态法研究了浮萍Lemna minor生物富集0.1、0.5、1.0、2.0 mg·L-1洛克沙胂、阿散酸(以砷计)的动力学过程.静态法的研究结果表明:大约55 d,浮萍生物富集各个质量浓度的洛克沙胂、阿散酸均基本达到平衡;0.1、0.5、1.0、2.0 mg·L-1洛克沙胂的生物富集系数(BCF)分别为:3 116.7、1 308.0、548.4、355.0;0.1、0.5、1.0、2.0 mg·L-1阿散酸的BCF分别为:690.0、341.1、255.9、179.8;而且浮萍对各个质量浓度的洛克沙胂、阿散酸的BCF随水体浓度升高而减小.半静态法研究结果表明:浮萍对洛克沙胂、阿散酸的生物富集系数(BCF)、吸收速率常数(K1)随水体质量浓度的增大而减小;同等质量浓度的洛克沙胂的吸收速率常数(K1)大于阿散酸.

EFFECTIVE CONCENTRATIONS OF 6 CONTAMINANTS TO LEMMA MINOR, PIMEPHALES PROMELA, DAPHNIA MAGNA, AND CERIODAPHNIA DUBIA

Science.gov (United States)

The research presented here resulted in EC50 and LOEC values for the contaminants copper, cadmium, diazinon, atrazine, and cyanide to the species Lemna Minor, Pimephales promelas, Daphnia magna, and Ceriodaphnia dubia. Observed values were used as benchmarks for assessing the se...

The maximization of the productivity of aquatic plants for use in controlled ecological life support systems (CELSS)

Science.gov (United States)

Thompson, B. G.

Lemna minor (common duckweed) and a Wolffia sp. were grown in submerged growth systems. Submerged growth increased the productivity/unit volume (P/UV) of the organisms and may allow these plants to be used in a controlled ecological life support system (CELSS).

Effects of aquatic vegetation type on denitrification

NARCIS (Netherlands)

Veraart, A.J.; Bruijne, de W.J.J.; Peeters, E.T.H.M.; Klein, de J.J.M.; Scheffer, M.

2011-01-01

In a microcosm 15N enrichment experiment we tested the effect of floating vegetation (Lemna sp.) and submerged vegetation (Elodea nuttallii) on denitrification rates, and compared it to systems without macrophytes. Oxygen concentration, and thus photosynthesis, plays an important role in regulating

Использование Ряски малой (Lemna minor) в процессе очистки промышленных стоков золоторудных предприятий в бассейне Р. Амур

OpenAIRE

Гула, К.

2012-01-01

В статье рассматриваются результаты эксперимента по очистке промышленных вод золотодобывающего предприятия с использованием Ряски малой (Lemna minor) из рода Ряска (Lemna L.) семейства рясковые (Lemnactat S.F. Gray). Показано, что степень извлечения ею загрязняющих веществ из сточных вод ЗИФ (золотоизвлекательной фабрики) значительно выше по сравнению с химическим методом, используемым на фабрике.The article discusses the results of the experiment to clean up industrial wastewater gold mining...

Adiciones a las haloragaceae de Colombia: Proserpinaca palustris

OpenAIRE

Schmidt Mumm Udo; Posada José Andrés

2000-01-01

Las especies colombianas de la familia Haloragaceae se han asignado a dos subfamilias y tres géneros. Según Mora-Osejo (1984), quién comparte la opinión de Schindler (1905) en incluir el género Gunnera L. en la sub familia terrestre Gunneroideae, la sub familia Haloragoideae distingue las plantas acuáticas y semiacuáticas de tallos herbáceos, raras veces subleñosos, hojas opuestas o verticiladas e inflorescencias terminales. Inicialmente se designaron dos especies del género Myriophyllum L. a...

青萍生长特征及其对受污染河水的修复效果%Growth characteristics and purification efficiencies of Lemna minor to polluted river water

Institute of Scientific and Technical Information of China (English)

鲁言言; 黄磊; 刘明; 杜刚; 高旭

2013-01-01

以浮萍优势品种青萍(Lemna minor)为研究对象,开展受污染河水修复.分析了青萍在不同营养盐浓度条件下的生长特征,探讨了青萍对受污染河水的修复效果.在表面积为0.0095 m2的限制空间条件下,青萍在1、2和5 mg总氮(TN)/L营养液中的生长特征都能较好地服从Logistic生长模型,受制约的临界鲜重(FW)分别为1.20、1.36和1.36 g；青萍对受污染河水中氮磷污染物具有较好的去除效果,氨氮(NH+4-N)的平均去除率、平均去除量和平均去除速率分别为56.87％、1.22 mg/d和0.0466 mg/(g FW·h),正磷酸盐(PO3-4-P)的平均去除率、平均去除量和平均去除速率分别为66.95％、0.25 mg/d和0.0088 mg/(g FW·h).根据相关性分析,进水NH+4-N和PO3-4-P浓度与其对应去除量之间极显著相关；青萍FW与NH+4-N去除速率之间显著负相关,但与P03-4-P去除速率之间不存在显著相关性；NH+4-N进水浓度与去除速率相关性不显著,但P03-4-P进水浓度与去除速率显著正相关.

Toxicity of 56 substances to trees

DEFF Research Database (Denmark)

Clausen, Lauge Peter Westergaard; Trapp, Stefan

2017-01-01

Toxicity data of substances to higher plants is needed for the purpose of risk assessment, site evaluation, phytoremediation, and plant protection. However, the results from the most common phytotoxicity tests, like the OECD algae and Lemna test, are not necessarily valid for higher terrestrial...

Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Great Plains Region (Version 2.0)

Science.gov (United States)

2010-03-01

These wetlands range from temporarily to permanently inundated and may be dominated by floating-leaved plants in deeper areas (e.g., Lemna ...more than one soil type or component. They often contain several minor components or inclusions of soils with properties that may be similar to or

An attempt to electrically enhance phytoremediation of arsenic contaminated water

NARCIS (Netherlands)

Kubiak, J.J.; Khankhane, P.J.; Kleingeld, P.J.; Lima, A.T.

2012-01-01

Water polluted with arsenic presents a challenge for remediation. A combination of phyto- and electro-remediation was attempted in this study. Four tanks were setup in order to assess the arsenic removal ability of the two methods separately and in combination. Lemna minor was chosen for As

Hydrothermal processing of biomass from invasive aquatic plants

Science.gov (United States)

W. James Catallo; Todd F. Shupe; Thomas L. Eberhardt

2008-01-01

The purpose of this study was to examine the hydrothermal (HT) treatment of three invasive aquatic plants (i.e., Lemna sp., Hydrilla sp., and Eichhornia sp.) with respect to the generation of semi-volatile hydrocarbon product mixtures and biomass volume reduction. Identical HT treatments yielded similar semi-...

Nuclear microscopy as a tool in TiO{sub 2} nanoparticles bioaccumulation studies in aquatic species

Energy Technology Data Exchange (ETDEWEB)

Pinheiro, Teresa, E-mail: murmur@itn.pt [IST/ITN, Instituto Superior Técnico, Universidade Técnica de Lisboa and Centro de Física Nuclear, Universidade de Lisboa (Portugal); Moita, Liliana; Silva, Luís; Mendonça, Elsa; Picado, Ana [LNEG, Laboratório Nacional de Energia e Geologia, I.P. Estrada do Paço do Lumiar 22, 1649-038 Lisboa (Portugal)

2013-07-01

Engineered Titanium nanoparticles are used for a wide range of applications from coatings, sunscreen cosmetic additives to solar cells or water treatment agents. Inevitably environmental exposure can be expected and data on the ecotoxicological evaluation of nanoparticles are still scarce. The potential effects of nanoparticles of titanium dioxide (TiO{sub 2}) on two model organisms, the water flea, Daphnia magna and the duckweed Lemna minor, were examined in semichronic toxicity tests. Daphnia and Lemna were exposed to TiO{sub 2} nanoparticles (average particle size value of 28 ± 11 nm (n = 42); concentration range, 1.4–25 mg/L) by dietary route and growth in medium containing the nanoparticles of TiO{sub 2}, respectively. Both morphology and microdistribution of Ti in the individuals were examined by nuclear microscopy techniques. A significant amount of TiO{sub 2} was found accumulated in Daphnia exposed to nanoparticles. Nuclear microscopy imaging revealed that Ti was localized only in the digestive tract of the Daphnia, which displayed difficulty in eliminating the nanoparticles from their body. Daphnia showed higher mortality when exposed to higher concentrations of TiO{sub 2} (>10 mg/L). The exposure to TiO{sub 2} nanoparticles above 25 mg/L caused morphological alterations in Lemna. The roots became stiff and fronds colorless. The Ti mapping of cross-sections of roots and fronds showed that Ti was mainly deposited in the epidermis of the fronds and roots, with minor internalization. In summary, exposure of aquatic organisms to TiO{sub 2} nanoparticles may alter the physiology of these organisms at individual and population levels, posing risks to aquatic ecosystems.

Nuclear microscopy as a tool in TiO2 nanoparticles bioaccumulation studies in aquatic species

Science.gov (United States)

Pinheiro, Teresa; Moita, Liliana; Silva, Luís; Mendonça, Elsa; Picado, Ana

2013-07-01

Engineered Titanium nanoparticles are used for a wide range of applications from coatings, sunscreen cosmetic additives to solar cells or water treatment agents. Inevitably environmental exposure can be expected and data on the ecotoxicological evaluation of nanoparticles are still scarce. The potential effects of nanoparticles of titanium dioxide (TiO2) on two model organisms, the water flea, Daphnia magna and the duckweed Lemna minor, were examined in semichronic toxicity tests. Daphnia and Lemna were exposed to TiO2 nanoparticles (average particle size value of 28 ± 11 nm (n = 42); concentration range, 1.4-25 mg/L) by dietary route and growth in medium containing the nanoparticles of TiO2, respectively. Both morphology and microdistribution of Ti in the individuals were examined by nuclear microscopy techniques. A significant amount of TiO2 was found accumulated in Daphnia exposed to nanoparticles. Nuclear microscopy imaging revealed that Ti was localized only in the digestive tract of the Daphnia, which displayed difficulty in eliminating the nanoparticles from their body. Daphnia showed higher mortality when exposed to higher concentrations of TiO2 (>10 mg/L). The exposure to TiO2 nanoparticles above 25 mg/L caused morphological alterations in Lemna. The roots became stiff and fronds colorless. The Ti mapping of cross-sections of roots and fronds showed that Ti was mainly deposited in the epidermis of the fronds and roots, with minor internalization. In summary, exposure of aquatic organisms to TiO2 nanoparticles may alter the physiology of these organisms at individual and population levels, posing risks to aquatic ecosystems.

Nuclear microscopy as a tool in TiO2 nanoparticles bioaccumulation studies in aquatic species

International Nuclear Information System (INIS)

Pinheiro, Teresa; Moita, Liliana; Silva, Luís; Mendonça, Elsa; Picado, Ana

2013-01-01

Engineered Titanium nanoparticles are used for a wide range of applications from coatings, sunscreen cosmetic additives to solar cells or water treatment agents. Inevitably environmental exposure can be expected and data on the ecotoxicological evaluation of nanoparticles are still scarce. The potential effects of nanoparticles of titanium dioxide (TiO 2 ) on two model organisms, the water flea, Daphnia magna and the duckweed Lemna minor, were examined in semichronic toxicity tests. Daphnia and Lemna were exposed to TiO 2 nanoparticles (average particle size value of 28 ± 11 nm (n = 42); concentration range, 1.4–25 mg/L) by dietary route and growth in medium containing the nanoparticles of TiO 2 , respectively. Both morphology and microdistribution of Ti in the individuals were examined by nuclear microscopy techniques. A significant amount of TiO 2 was found accumulated in Daphnia exposed to nanoparticles. Nuclear microscopy imaging revealed that Ti was localized only in the digestive tract of the Daphnia, which displayed difficulty in eliminating the nanoparticles from their body. Daphnia showed higher mortality when exposed to higher concentrations of TiO 2 (>10 mg/L). The exposure to TiO 2 nanoparticles above 25 mg/L caused morphological alterations in Lemna. The roots became stiff and fronds colorless. The Ti mapping of cross-sections of roots and fronds showed that Ti was mainly deposited in the epidermis of the fronds and roots, with minor internalization. In summary, exposure of aquatic organisms to TiO 2 nanoparticles may alter the physiology of these organisms at individual and population levels, posing risks to aquatic ecosystems

Tratamiento de aguas eutrofizadas de la bahía interior de Puno, Perú, con el uso de dos Macrófitas

OpenAIRE

Jimenez Monroy, Luis Llberto; Jahuira Huarcaya, Faustino Adolfo; Ibañez Quispe, Vladimiro

2016-01-01

La investigación tuvo como propósito determinar los niveles de Nitrógeno Total (NT) y Fósforo Total (PT) de las aguas contaminadas de la bahía interior de la ciudad de Puno, del sector denominado Isla Espinar, de la boca toma de muelle, sector Huaje, y evaluar la eficiencia de dos macrófitas, como el Elodea Canadensis Michax (llacho) y Myriophyllum Quitensis Kunth (hinojo) para la remoción del Nitrógeno y Fósforo. Para valorar las muestras, procedentes del sector Parinas de la Península de Ch...

稀脉萍对水中甲基橙的毒害响应及去除研究%Study on Toxic Response of Lemna Aequinoctialis to Methyl Orange and Removal of Methyl Orange

Institute of Scientific and Technical Information of China (English)

陈秋平; 胥思勤

2014-01-01

Methyl orange was used as an environmental stress factor to examine the effects on enzyme activity of peroxidase,content of soluble protein,and chlorophyll content of Lemna aequinoctialis leaves.L.aequinoctialis was applied to removal Methyl orange.The results showed that enzyme activity of peroxidase rised first and then fell with the increase of Methyl orange concentration.When Methyl orange concentration was 1 40 mg/L,enzyme activi-ty of peroxidase came to the maximum.When Methyl orange concentration was more than 1 00 mg/L,soluble pro-tein content dropped rapidly.The chlorophyll content and the ratio of chlorophyll a to chlorophyll b decreased with the increase of Methyl orange concentration.When Methyl orange concentration was 20 mg/L,there was a 1 0 -day lag period.Then the degradation rate of Methyl orange could reach 89.6 %after L.aequinoctialis was cultured 24 days.%用甲基橙作为胁迫因子，研究了甲基橙对稀脉萍叶片过氧化物酶活性、可溶性蛋白含量和叶绿素含量的影响，并采用稀脉萍去除甲基橙。结果表明：随着甲基橙浓度的增加，过氧化物酶活性呈先上升后下降的趋势，当甲基橙浓度为140mg／L时，过氧化物酶活性达到最高值。当甲基橙浓度＞100mg／L，可溶性蛋白含量急速下降。叶绿素含量和叶绿素a／b比值均随甲基橙浓度的升高而降低。当甲基橙浓度为20 mg／L时，稀脉萍对甲基橙的去除需经10 d的延滞期，24 d后去除率达89.6％。

Application of macrophytes as biosorbents for radioactive liquid waste treatment; Aplicacao de macrofitas como biossorventes no tratamento de rejeitos radioativos liquidos

Energy Technology Data Exchange (ETDEWEB)

Vieira, Ludmila Cabreira

2016-07-01

Radioactive waste as any other type of waste should be treated and disposed adequately. It is necessary to consider its physical, chemical and radiological characteristics for choosing the appropriate action for the treatment and final disposal. Many treatment techniques currently used are economically costly, often invalidating its use and favoring the study of other treatment techniques. One of these techniques is biosorption, which demonstrates high potential when applied to radioactive waste. This technology uses materials of biological origin for removing metals. Among potential biosorbents found, macrophyte aquatics are useful because they may remove uranium present in the liquid radioactive waste at low cost. This study aims to evaluate the biosorption capacity of macrophyte aquatics Pistia stratiotes, Limnobium laevigatum, Lemna sp and Azolla sp in the treatment of liquid radioactive waste. This study was divided into two stages, the first one is characterization and preparation of biosorption and the other is tests, carried out with uranium solutions and real samples. The biomass was tested in its raw form and biosorption assays were performed in polypropylene vials containing 10 ml of solution of uranium or 10ml of radioactive waste and 0.20g of biomass. The behavior of biomass was evaluated by sorption kinetics and isotherm models. The highest sorption capacities found was 162.1 mg / g for the macrophyte Lemna sp and 161.8 mg / g for the Azolla sp. The equilibrium times obtained were 1 hour for Lemna sp, and 30 minutes for Azolla sp. With the real waste, the macrophyte Azolla sp presented a sorption capacity of 2.6 mg / g. These results suggest that Azolla sp has a larger capacity of biosorption, therefore it is more suitable for more detailed studies of treatment of liquid radioactive waste. (author)

Application of macrophytes as biosorbents for radioactive liquid waste treatment

International Nuclear Information System (INIS)

Vieira, Ludmila Cabreira

2016-01-01

Radioactive waste as any other type of waste should be treated and disposed adequately. It is necessary to consider its physical, chemical and radiological characteristics for choosing the appropriate action for the treatment and final disposal. Many treatment techniques currently used are economically costly, often invalidating its use and favoring the study of other treatment techniques. One of these techniques is biosorption, which demonstrates high potential when applied to radioactive waste. This technology uses materials of biological origin for removing metals. Among potential biosorbents found, macrophyte aquatics are useful because they may remove uranium present in the liquid radioactive waste at low cost. This study aims to evaluate the biosorption capacity of macrophyte aquatics Pistia stratiotes, Limnobium laevigatum, Lemna sp and Azolla sp in the treatment of liquid radioactive waste. This study was divided into two stages, the first one is characterization and preparation of biosorption and the other is tests, carried out with uranium solutions and real samples. The biomass was tested in its raw form and biosorption assays were performed in polypropylene vials containing 10 ml of solution of uranium or 10ml of radioactive waste and 0.20g of biomass. The behavior of biomass was evaluated by sorption kinetics and isotherm models. The highest sorption capacities found was 162.1 mg / g for the macrophyte Lemna sp and 161.8 mg / g for the Azolla sp. The equilibrium times obtained were 1 hour for Lemna sp, and 30 minutes for Azolla sp. With the real waste, the macrophyte Azolla sp presented a sorption capacity of 2.6 mg / g. These results suggest that Azolla sp has a larger capacity of biosorption, therefore it is more suitable for more detailed studies of treatment of liquid radioactive waste. (author)

ASSESSMENT OF IMPACT OF COHERENT LIGHT ON RESISTANCE OF PLANTS GROWING IN UNFAVOURABLE ENVIRONMENTAL CONDITIONS

Directory of Open Access Journals (Sweden)

Małgorzata Śliwka

2014-04-01

Full Text Available The results of experiments on the effect of the coherent light emitted by lasers on plant material show that properly selected laser stimulation parameters, such as: wavelength, power, time and type of exposure, allow to obtain a greater growth of plant biomass, changes in the content of elements in the biomass and increasing plant resistance to unfavorable environmental conditions. The aim of this study was to determine the effect of laser stimulation on selected plant species (Iris pseudoacorus L., Lemna minor L. to increase their resistance to low temperatures and the ability to adapt to an environment polluted by mining activities (Phelum pratense L.. Plants from experimental groups (Iris pseudoacorus L., Phelum pratense L., Lemna minor L. were stimulated with coherent light with specific characteristics. To irradiate plants from experimental groups different algorithms of stimulation parameters, differentiating the method and time of exposure were used. Plants group without the stimulation, were the reference group. The article discusses the results of preliminary experiments carried out on a laboratory scale and pot experiments.

Ecogenotoxicity testing of aquatic environment by comet assay in plants

Directory of Open Access Journals (Sweden)

Anita Mukherjee

2015-05-01

Full Text Available One of the goals of environmental monitoring is the detection of potentially hazardous compounds in water. We have set up a standard method to apply the Comet assay in aquatic plants that could be of great interest to evaluate cytotoxicity, genotoxicity and oxidative stress on the same species regarded as most sensitive to environmental pollutants. The aim of the present study was to set up of standardized procedure to evaluate genotoxicity in aquatic plants- Ceratophyllum demersum one that is submerged free floating and the other is Lemna minor - a fresh water floating plant by Comet assay. Electrophoresis and unwinding times were adapted to obtain minimum DNA migration evaluated as tail intensity % or tail moment in the control group and, at the same time maximum sensitivity for DNA damage with known genotoxicants. We further investigated the cytotoxicity and oxidative stress induced in the same species. Based on the repeatability of results obtained we suggest that Ceratophyllum, Lemna can serve as model species and Comet assay could be adopted to monitor the eco-genotoxicity of water pollutants.

Ecotoxiocological Studies of Niger Delta Sediments using Duckweed (L. Minor) Growth Inhibition Test

International Nuclear Information System (INIS)

Olajire, A. A.; Alternburger, R.; Brack, W.

2003-01-01

This study was undertaken to evaluate the toxicity of sediments collected from the Niger Delta (Nigeria) to Lemna minor, a sensitive aquatic weed regularly used for ecotoxicological studies. Also, the study wanted to determine if L. minor can be used as an effective bioassay organism by oil companies and chemical industries in Nigeria. Essentially, the experimental approach involved exposure of L. minor under standard laboratory conditions to sediments and toxicity is presented as percent inhibition of growth of L. minor cultures after 7 days. The result of the present study showed that there is differential toxicity among the sediments analyzed, and we found that for 0.25mg/ml of growth rate (%1) decreases in the order: SDOGN(42.6%) >SDWRR (33.7%)> SDALD (20.5%) >SDUGBO (17.1%) ? SDWRR were clorotic and had lost their roots, indicating the very high toxicity of the soluble organic contaminants in these sediments. Lemna minor proved to be a practical bioassay organism because the L. minor toxicity test is simple, sensitive and cost effective

Analytical procedures for bulk frozen-hydrated biological tissues

International Nuclear Information System (INIS)

Echlin, P.; Hayes, T.L.; McKoon, M.

1983-01-01

The main advantage of using solid frozen samples for elemental x-ray microanalysis is the ease with which they may be prepared and maintained in the frozen-hydrated state. Within the limits imposed by the reduced spatial resolution of the method, the morphological identification of the tissue components is comparatively easy. Bearing in mind these limitations, the authors have carried out an analysis for several elements in the developing root tips of Lemna minor L (Duckweed). Fresh root tips of Lemna minor L, briefly encapsulated in a polymeric cryoprotectant, are quench frozen in melting nitrogen at ca. 70 0 K and transferred to the pre-cooled cold stage of an AMray Biochamber. The analysis was carried out by means of a Kevex energy-dispersive detector by use of the peak-to-background ratio method. These procedures allow the authors to obtain flat fracture faces in which they have been able to measure the relative concentrations of various elements at the various stages of differentiation in the root tissue

Macrophyte distribution and ecological status of the Turiec River (Slovakia: Changes after seven years

Directory of Open Access Journals (Sweden)

Hrivnák R.

2009-01-01

Full Text Available Characteristics of diversity, abundance, distribution, and ecological status of aquatic macrophytes were observed in 2000 and 2007 on a circa 4.5 km long section of the Turiec River using Kohler's method. In comparison to 2000, the total number of macrophytes in 2007 increased markedly (from 25 to 35, although only the numbers of amphi­phytes and helophytes were changed substantially. The number of hydrophytes increased from 11 to 12; an invasive, Elodea canadenis, was the only new species. The relative plant mass of hydrophytes represents the bulk of all recorded species (95 and 80% in 2000 and 2007, respectively, and it was changed for most hydrophytes. The most significant changes were detected for Myriophyllum spicatum (decrease, filamentous algae (decrease, and Potamogeton crispus (increase. In 2007, the mean mass total (MMT sum of hydrophytes decreased from 16.46 to 14.5. On the other hand, the MMTsum of amphiphytes and helophytes doubled in value (7.4 and 14.1 in 2000 and 2007, respectively. Within hydrophytes, Batrachium species (including B. aquatile and B. trichophyllum, Myriophyllum spicatum, and Potamogeton crispus were ubiquitous (distribution ratio d > 0.5 in 2000, whereas in 2007 only Batrachium species and Potamogeton crispus were ubiquitous. At all times, Batrachium species were the most frequent species in the study area, and their abundance was relatively high (MMT> 2.5. A poor ecological status (MMP = 0.378 and MMP = 0.333 in 2000 and 2007, respectively of the surveyed river section was found in both years, but a slight decline of quality as determined on the basis of aquatic plants was observed after 7 years.

Uptake of Different Forms of Nitrogen and Phosphorus by Three Aquatic Plants%3种水生植物对不同形态氮·磷吸收的研究

Institute of Scientific and Technical Information of China (English)

杨小霞; 黄晓典; 赵超; 彭少华; 韩磊

2012-01-01

[目的]探讨水蓼、浮萍和黑藻在水体氮、磷去除中的应用价值.[方法]在室内培养条件下,比较这3种水生植物对不同形态和浓度氮、磷的吸收效果.[结果]3种植物发挥最大N、P吸收效果的水体N、P浓度分别为1和5 mg/L.经10 d的培养,3种水生植物对铵态氮和硝态氮的去除率均达50％以上,其中浮萍对铵态氮的去除率高达63.6％；3种水生植物对磷的去除以正磷酸盐最佳,焦磷酸盐次之,偏磷酸盐最差.浮萍对这3种形态磷的去除效果均最好,去除率分别为94.7％、85.6％和70.9％.[结论]浮萍可以作为一种净化植物,可以有效地降低水中铵态氮和不同形态磷浓度.%[Objective]The nitrogen and phosphorus absorption in water by Polygonum hydropiper L. , Hydrilla verticillata (L. f. ) Royle and Lemna minor L. were studied. [Method]The uptake of nitrogen and phosphorus with different forms and concentrations by three aquatic plants was evalulated under laboratary conditions. [Result]The concentrations of N and P in water which made the plants achieve the hightest uptake of the two elements were 1 and 5 mg/L, respectively. The removal rates of NH4-N and N03-N by three plants were over 50% after 10 days treatment, and the highest removal rate (63.6% ) for NH4-N was found in Lemna minor L. Among the different forms of phosphorus, the removal efficiency by plants was followed as orthophosphate > pyrophosphate > metaphosphate. Lemna minor L. had the best removal rate for three forms of phosphorus, with a removal rate of 94.7% , 85.6% and 70.9% , respectively. [Conclusion]Lemna minor L. was an idea plant for efficient removal of NH4-N and different forms of phosphorus in water.

太湖流域浮萍种质资源及其生长水环境调查

Institute of Scientific and Technical Information of China (English)

张飞; 唐杰; 马炯; 成家杨

2016-01-01

对太湖流域多个县(市)浮萍分布情况进行调查,观测各地浮萍种类及其生长水体的水质状况,探讨水体pH值,铵态氮、硝态氮、总氮、总磷含量及其与浮萍分布的关系.调查结果表明,浮萍适宜生长在静止的水体中,流动的河流中较为少见.太湖流域采集到3属5种浮萍,分别为Spirodela polyrrhiza、Lemna minor、Lemna turionifera、Lemna aequinoctialis、Landoltia punctata.其中,紫萍属(Spirodela genera)和青萍属(Lemna genera)分别占到49％和37％,为该地区主要的浮萍种类.少根紫萍适宜在中性的环境中生长,而紫萍适宜生长在偏碱性的水体中;相对而言,青萍生长的pH范围更广,在pH值6.34 ～ 8.78均有分布.太湖流域浮萍生长水环境中氮、磷含量范围较广,铵态氮、硝态氮、总氮和总磷质量浓度范围分别为0.28～19.67、0.01 ～5.18、0.10 ～24.62、0.03 ～ 2.45 mg/L.尚未发现自然环境中浮萍的分布与水体氮、磷含量间的必然联系.调查还发现,太湖流域浮萍淀粉含量在10.95％～23.27％之间,均值为15.95％.在太湖流域水生植物修复过程中,可优先考虑利用当地优势浮萍品种及不同品种浮萍的共生复合系统,构建浮萍塘生态系统,来去除水体中的氮、磷等营养物质.

Environmental Assessment: Land Acquisition at Whiteman Air Force Base, Missouri

Science.gov (United States)

2011-06-01

Canadian clearweed (Pilea pumila), common duckweed ( Lemna minor ), common rush (Juncus effusus), cottonwood (Populus deltoides), crabgrass...resources, hazardous materials and hazardous waste, and safety. Implementation of the Proposed Action would result in minor , short-term adverse impacts...consumption of petroleum products during fence construction. As a result of implementing the Proposed Action, minor long-term adverse impacts to land use

A no iso ovel po lation olymera of a ne ase ch ew rbc hain rea cS ...

African Journals Online (AJOL)

sunny

Hubei Norma ed 14 December, ymerase cha mosome wa ndle PCR in i. 3' downstrea mna minor ge isolated from ch was confi ion-mediated s in the isola. Lemna minor es have be omic fragme without go nomic librar chain react y been appl al PCR metho. Inverse PC and Chen, 200 gation-mediat. Villalobos et a. 2003; Dai ...

Mycorrhizal and Saprophytic edible fungi as biological indicators for environmental radioactivity

International Nuclear Information System (INIS)

Gaso, M.I.; Segovia, N.; Cervantes, M.L.

2002-01-01

40 K and 137 Cs specific activities were determined in soil and in 137 mushroom samples belonging to 32 edible mushroom species from a forest ecosystem located in Mexico. Among all the species investigated, 15 were mycorrhizal fungi and 15 were saprophytes. 40 K specific activities lay within a range from 332 to 2070 (Bq kg -1 , dry weight), with the lower value corresponding to the saprophytic fungi Clitocybe gibba and the higher value to the ectomycorrhizal Amanita cesarea. The 137 Cs concentration determined in mycorrhizal fungi was also higher than in saprophytes. The contribution from mushrooms to the dietary intake of 40 K was estimated to be several times higher than the corresponding component of annual intake calculated for 137 Cs. (orig.)

Sequential ethanol fermentation and anaerobic digestion increases bioenergy yields from duckweed.

Science.gov (United States)

Calicioglu, O; Brennan, R A

2018-06-01

The potential for improving bioenergy yields from duckweed, a fast-growing, simple, floating aquatic plant, was evaluated by subjecting the dried biomass directly to anaerobic digestion, or sequentially to ethanol fermentation and then anaerobic digestion, after evaporating ethanol from the fermentation broth. Bioethanol yields of 0.41 ± 0.03 g/g and 0.50 ± 0.01 g/g (glucose) were achieved for duckweed harvested from the Penn State Living-Filter (Lemna obscura) and Eco-Machine™ (Lemna minor/japonica and Wolffia columbiana), respectively. The highest biomethane yield, 390 ± 0.1 ml CH 4 /g volatile solids added, was achieved in a reactor containing fermented duckweed from the Living-Filter at a substrate-to-inoculum (S/I) ratio (i.e., duckweed to microorganism ratio) of 1.0. This value was 51.2% higher than the biomethane yield of a replicate reactor with raw (non-fermented) duckweed. The combined bioethanol-biomethane process yielded 70.4% more bioenergy from duckweed, than if anaerobic digestion had been run alone. Copyright © 2018 Elsevier Ltd. All rights reserved.

EFECTOS DEL MERCURIO SOBRE ALGUNAS PLANTAS ACUÁTICAS TROPICALES

Directory of Open Access Journals (Sweden)

Martha Isabel Posada

Full Text Available El presente artículo es una descripción de los efectos del mercurio sobre algunas plantas acuáticas tropicales y sobre los ecosistemas donde habitan. Adicionalmente, se recomienda un protocolo para realizar pruebas de toxicidad con la lenteja de agua (Lemna minor y se presentan los resultados de los preensayos con diferentes concentraciones de sales de mercurio en condiciones de laboratorio. Se encontró que la biodisponibilidad del mercurio depende de factores que facilitan la disolución del elemento en el agua. Algunas plantas actúan como bioindicadores de la presencia de este metal en el medio al retenerlo selectivamente; mientras que otras se comportan como bioacumuladoras al tolerar su presencia y acumularlo en su estructura, y pueden dar paso a la bioconcentración a través de la cadena trófica. De acuerdo con los preensayos de toxicidad realizados con Lemna minor se sugiere que las concentraciones de sal de mercurio adecuadas para la realización de pruebas de toxicidad deben estar entre 0,01 mg/L y 10,0 mg/L.

Preliminary Ecotoxicity and Biodegradability Assessment of Metalworking Fluids

Science.gov (United States)

Gerulová, Kristína; Amcha, Peter; Filická, Slávka

2010-01-01

The main aim of this study was to evaluate the potential of activated sludge from sewage treatment plant to degrade selected MWFs (ecotoxicity to bacterial consortium) and to evaluate the ecotoxicity by Lemna minor-higher plant. After evaluating the ecotoxicity, biodegradations rate with activated sludge was assessed on the basis of COD measurement. Preliminary study of measuring the ecotoxicity according to OECD 221 by Lemna minor shows effective concentration of Emulzin H at the rate of 81.6 mg l-1, for Ecocool 82.9 mg l-1, for BC 25 about 99.3 mg l-1, and for Dasnobor about 97.3 mg l-1. Preliminary study of measuring the ecotoxicity by bacterial consortium according to OECD 209 (STN EN ISO 8192) shows effective concentration of Blasocut BC 25 at the rate 227.4 mg l-1. According to OECD 302B, the biodegradations level of Emulzin H, Ecocool and BC 25 achieved 80% in 10 days. It can be stated that these MWFs have potential to ultimate degradation, but the statement has to be confirmed by a biodegradability test with other parameters than COD, which exhibits some disadvantages in testing O/W emulsions.

咪鲜胺及其制剂和主要代谢物对三叶浮萍SOD和POD活性的影响%Effect of Prochloraz, Its Formulation and Major Metabolites on the Activities of SOD and POD in Lemna pau-cicostata

Institute of Scientific and Technical Information of China (English)

卫麦霞; 龚道新; 黎定军; 任竞; 刘名扬; 汪传刚

2008-01-01

为了全面正确地评价咪鲜胺及其制剂和主要代谢物施用后的生态环境效应和生物毒性,以三叶浮萍(Lemna Paucicostata)为实验材料,采用光照恒温培养法,研究了咪鲜胺及其制剂和主要代谢物(包括BTS44595、BTS44596和BTS45186)对三叶浮萍体内超氧化物歧化酶(SOD)和过氧化物酶(POD)活性的影响.结果表明,随着处理浓度的升高,Prochloraz、Sportak、BTS44595和BTS44596对SOD活性和POD活性的影响由激活作用转变为抑制作用,而BTS45186对SOD和POD活性的影响则表现为抑制作用,且浓度越高,对SOD和POD活性的抑制作用越强;Prochloraz和Sportak对SOD和POD活性的影响较大, 但两者之间的差异不大,不过Proehloraz对三叶浮萍的SOD和POD活性的影响早于Sportak的影响.Pmchloraz及其主要代谢产物对SOD和POD活性影响的大小顺序 :B3S45186>Prochloraz>BTS44596>BTS44595.这说明Prochloraz降解为代谢产物BTS44595和BTS44596的过程是一个毒性下降的解毒过程,而BTS44595和BTS44596降解为BTS45186的过程是一个毒性上升的增毒过程.

Environmental Assessment: Permanent Western United States C-17 Landing Zone

Science.gov (United States)

2008-09-01

Salix sp., Populus sp., Lemna minor , Cyperus sp. Delta Green Ground Beetle The Delta Green Ground Beetle, Elaphrus viridis Horn, 1878 is a...and the SCLA. Cumulative impacts can result from individually minor but collectively significant actions taking place over a period of time. None of...environmental effects on adjacent populations. Therefore, no disproportionately high and adverse effects will occur to minority and low-income

Biofuel Production: Considerations for USACE Civil Works Business Lines

Science.gov (United States)

2014-12-01

feedstock for biofuel production has led to research whereby several genera of duckweed ( Lemna , Landoltia, Spirodela, Wolffia, Wolfiella) have been...as well as the general public when rendering its final permit decisions. Regulatory responsibilities include evaluating minor activities such as...reservoirs scattered along minor river systems in other parts of the United States (Kasul et al. 1998) Through a series of legislative acts in the

Amino acid metabolism of Lemna minor L

International Nuclear Information System (INIS)

Rhodes, D.; Rich, P.J.; Brunk, D.G.

1989-01-01

A serious limitation to the use of N(O,S)-heptafluorobutyryl isobutyl amino acid derivatives in the analysis of 15 N-labeling kinetics of amino acids in plant tissues, is that the amides glutamine and asparagine undergo acid hydrolysis to glutamate and aspartate, respectively, during derivatization. This led us to consider an alternative procedure for derivatization of glutamine and asparagine with N-methyl-N-(tert-butyldimethylsilyl)-trifluoroacetamide in pyridine. Gas chromatography-mass spectrometry yielded fragment ions (M-57) of mass 417 and 431 for the [ 14 N]asparagine and [ 14 N]glutamine derivatives, respectively, suitable for monitoring unlabeled, single- 15 N- and double- 15 N-labeled amide species from the ion clusters at mass to charge ratio (m/z) 415 to 423 for asparagine, and m/z 429 to 437 for glutamine. From separate analyses of the specific isotope abundance of the amino-N groups of asparagine and glutamine as their N-heptafluorobutyryl isobutyl derivatives, the specific amide-[ 15 N] abundance of these amino acids was determined

Using Lemna to Study Geometric Population Growth.

Science.gov (United States)

DeBuhr, Larry E.

1991-01-01

An experiment in which students collect and analyze data on the population size of a real organism rather that on a model is presented. The activity allows for the integration of mathematics, graphing techniques, and the use of computers. The lesson is designed to follow the learning cycle format. (KR)

Phosphorus Uptake Kinetics of Different Types of Duckweed.%不同品种浮萍磷素吸收动力学特征

Institute of Scientific and Technical Information of China (English)

蔡树美; 刘文桃; 张震; 柏彦超; 钱晓晴

2011-01-01

以长江三角洲地区常见的3种浮萍--稀脉浮萍(Lemna aequinoctialis)、少根紫萍(Spirodela oligorrhiza)和紫萍(Spriodela polyrrhiza)为对象,研究不同品种浮萍对HPO42-的吸收动力学影响.结果表明,3种浮萍对无机磷的吸收动力学特征基本可采用Michaelis-Menten方程描述,3种浮萍无机磷吸收速率V对磷浓度S双倒数曲线的拟合关系均在α=0.01水平上显著.稀脉浮萍对无机磷的亲和力较强,适宜应用于对低磷浓度污水的净化;紫萍对无机磷的最大吸收速率Vmax较高,适宜应用于对高磷浓度污水的净化.%An increasing attention has been paid to the use of duckweed in treating eutrophicated water as a tool of bio-remediation of domestic wastewater.Phosphorus uptake kinetics was studied,of different species of duckweeds, i.e.Lemna aequinoctialis, Spirodela oligorrhiza and Spriodela polyrrhiza, which are common in the Yangtze River Delta area.Results show that the phosphorus uptake kinetics of the duckweeds could be expressed with the Michaelis-Menten equation; and the relation between phosphorus uptake rate (V) of the duckweeds and inorganic phosphorus(Pi) concentration (S), was well fitted with a double-reciprocal curve with at =0.01; the Km value for Pi uptake of Lemna aequinoctialis was lower than that of Spirodela oligorrhiza and Spriodela polyrrhiza, making it a better candidate for treating wastewater low in Pi concentration.The maximum phosphorus uptake rate of Spriodela polyrrhiza was higher than that of the other two species, which allows Spriodela polyrrhiza better performance in purifying wastewater higher in Pi concentration.

Growth Feature of Biomass of Lemna aequinoctialis and Spirodela polyrrhiza in Medium with Nutrient Character of Wastewater%细脉浮萍和紫背浮萍在污水营养条件下的生长特性

Institute of Scientific and Technical Information of China (English)

种云霄; 胡洪营; 钱易

2004-01-01

浮萍类植物是污水生态工程处理技术中吸收转化氮磷等营养物质的重要植物类群.氮磷是浮萍生长所必需的主要结构组成物质,因此浮萍生物量的增长速率决定了其对氮磷吸收转化的能力.本研究采用序批式培养和连续式培养2种方式探讨了细脉浮萍(Lemna aequinoctialis) 和紫背浮萍(Spirodela polyrrhiza) 在污水营养条件下的生长特性,并利用单种种群增长的Logistic模型对生物量的增长曲线进行了分析.研究结果表明浮萍的鲜生物量和干重随时间变化的增长曲线具有"S"型特点,在特定的环境和营养条件下,单位面积上浮萍生物量的增长受密度的制约.Logistic拟合的结果表明浮萍生物量的增长符合种群的Logistic增长规律,浮萍在有限环境中生物量有最大值:最大承载量,当密度达到最大承载量一半时,其生物量的增长速率最大.实验结果及模型分析结果均表明2种浮萍在氨氮人工培养液中的生长速率比在硝酸氮培养液中低.细脉浮萍生长速率及含水率均高于紫背浮萍.本文还探讨了浮萍的Logistic增长规律在浮萍生物量收获管理中的应用.

Effects of Duckweed on Nitrogen and Phosphorus Removal in Reclaimed Wastewater%浮萍去除污水处理厂出水中氮磷的比较研究

Institute of Scientific and Technical Information of China (English)

辛静; 张震; 钱晓晴; 蔡树美

2011-01-01

以经筛选得到的本地优化浮萍晶种——少根紫萍和稀脉浮萍为供试材料,以扬州某污水处理厂二级出水为供试水,考察了夏季气象条件下两种浮萍对水中氮、磷的去除及其自身积累氮、磷的情况,并作出相应的比较.结果表明:放养稀脉浮萍的水中总氮、总磷的去除量分别是放养少根紫萍的水中总氮、总磷去除量的1.6倍和2.2倍；稀脉浮萍体内积累的氮、磷分别是少根紫萍积累的1.6倍和1.9倍.供试水体中总氮的去除量与浮萍体内氮养分的积累量动态非常类似,但前者明显大于后者,水中氮的去除尚存在其他途径；总磷的去除量与浮萍体内磷养分的积累量动态也十分类似,二者在数量上十分接近,说明水体中磷的去除主要是通过浮萍对磷的吸收来实现的.%Two local species, Lemna perpusilla and Spirodela oligorrhiza were chosen to grow in water taken from the secondary effluent of a wastewater treatment plant in Yangzhou. Removal abilities of total nitrogen (TN) and total phosphorus (TP) as well as retention of nitrogen and phosphorus in these two duckweed species were compared. Results showed that Lemna perpusilla had higher removal efficiency than that of Spirodela oligorrhiza. TN and TP removed by Lemna perpusilla were 1.6 and 2.2 times as those by Spirodela oligorrhiza, while TN and TP retention in Lemna perpusilla were 1.6 and 1.9 times as those in Spirodela oligorrhiza. Dynamics of TN removal and plant retention were similar, but significantly higher TN removal from wastewater were determined than TN in duckweed plants, which implied other possible TN removal strategies might have been involved. Amount of TP removed from wastewater was close to TP in plants, indicating absorption of duckweed as a major pathway of TP removal.

Mycorrhizal and Saprophytic edible fungi as biological indicators for environmental radioactivity

Energy Technology Data Exchange (ETDEWEB)

Gaso, M.I.; Segovia, N.; Cervantes, M.L. [ININ, Mexico D.F. (Mexico)

2002-03-01

{sup 40}K and {sup 137}Cs specific activities were determined in soil and in 137 mushroom samples belonging to 32 edible mushroom species from a forest ecosystem located in Mexico. Among all the species investigated, 15 were mycorrhizal fungi and 15 were saprophytes. {sup 40}K specific activities lay within a range from 332 to 2070 (Bq kg{sup -1}, dry weight), with the lower value corresponding to the saprophytic fungi Clitocybe gibba and the higher value to the ectomycorrhizal Amanita cesarea. The {sup 137}Cs concentration determined in mycorrhizal fungi was also higher than in saprophytes. The contribution from mushrooms to the dietary intake of {sup 40}K was estimated to be several times higher than the corresponding component of annual intake calculated for {sup 137}Cs. (orig.)

Growth and Development of Three-Dimensional Plant Form.

Science.gov (United States)

Whitewoods, Christopher D; Coen, Enrico

2017-09-11

Plants can generate a spectacular array of complex shapes, many of which exhibit elaborate curvature in three dimensions, illustrated for example by orchid flowers and pitcher-plant traps. All of these structures arise through differential growth. Recent findings provide fresh mechanistic insights into how regional cell behaviours may lead to tissue deformations, including anisotropies and curvatures, which shape growing volumes and sheets of cells. Here were review our current understanding of how genes, growth, mechanics, and evolution interact to generate diverse structures. We illustrate problems and approaches with the complex three-dimensional trap of the bladderwort, Utricularia gibba, to show how a multidisciplinary approach can be extended to new model systems to understand how diverse plant shapes can develop and evolve. Copyright © 2017 Elsevier Ltd. All rights reserved.

泽漆水浸液及茶皂素浸提液对浮萍的抑制效果%Study on the inhibitory effect of Euphorbia helioscopia L.aqueous extract with and without tea saponin on Lemna minor L.

Institute of Scientific and Technical Information of China (English)

张乐婷; 张饮江; 张曼曼; 金晶; 陈晓君; 段婷; 王芳

2014-01-01

通过对浮萍表观生长状态的观察记录以及对其抗氧化酶、丙二醛含量的测定,研究泽漆水浸液对浮萍(Lemna minor L.)的抑制活性,并探索利用茶皂素作为浸提辅助剂,检测是否提高泽漆对浮萍的抑制作用.结果表明:低浓度泽漆水浸液(0.001、0.003、0.005 g/mL)胁迫下,浮萍部分抗氧化酶系统遭受破坏,过氧化氢酶、过氧化物酶活性下降,超氧化物歧化酶活性先升高后降低,未出现明显表观受伤症状;高浓度泽漆水浸液(0.01、0.015、0.02 g/mL)胁迫36 h,90％～100％个体受伤严重甚至死亡,受伤个体、程度与浓度、时间成正比,茶皂素助浸液胁迫36 h时,出现明显受伤症状的个体数≤10％.茶皂素作为浸提辅助剂所得泽漆浸提液没有加强对浮萍的抑制作用,反而减弱了这种作用.泽漆水浸液对浮萍有明显的抑制作用,今后可进一步分析泽漆水浸液和其茶皂素助浸液之间化学成分种类和含量的差异,这有助于抑制浮萍有效成分的鉴定.

Alternativas ecotecnológicas en la depuración de aguas residuales derivadas de la acuicultura y la producción animal

OpenAIRE

González Salas, R.; Romero Cruz, O.; Vidal del Río, M.; Ponce-Palafox, J.T.

2010-01-01

Water bodies have increasingly got polluted in the last years due to unappropriate management of wastewaters having urban, industrial and agricultural origen, especially in less Developer nations. Development of ecotechnological alternatives through the use of aquatic plants such as Lemna sp. allows making use of natural resources and thus purify high contaminating loads that are produced by cattle raising and agricultural refuses, generating at the same time large amounts of b...

AMEG: the new SETAC advisory group on aquatic macrophyte ecotoxicology

OpenAIRE

Arts, G.; Davies, J.; Dobbs, M.; Ebke, P.; Hanson, M.; Hommen, U.; Knauer, K.; Loutseti, S.; Maltby, L.; Mohr, S.; Poovey, A.; Poulsen, V.

2010-01-01

\\ud Introduction and background\\ud \\ud Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test species is the floating (non-sediment-rooted) duckweed Lemna spp. This macrophyte species might not be representative of all floating, rooted, emergent, and submerged macrophyte species be...

AMEG: the new SETAC advisory group on auqatic macrophyte ecotoxicology

OpenAIRE

Arts, G.H.P.; Davies, J.; Dobbs, M.; Ebke, P.; Hanson, M.A.

2010-01-01

ntroduction and background Primary producers play critical structural and functional roles in aquatic ecosystems; therefore, it is imperative that the potential risks of toxicants to aquatic plants are adequately assessed in the risk assessment of chemicals. The standard required macrophyte test species is the floating (non-sediment-rooted) duckweed Lemna spp. This macrophyte species might not be representative of all floating, rooted, emergent, and submerged macrophyte species because of dif...

Use of tracer tests to evaluate hydraulic properties of constructed wetlands

International Nuclear Information System (INIS)

Wachniew, P.; Czuprynski, P.; Maloszewski, P.

2004-01-01

Knowledge of hydraulic properties is a perquisite for studies of constructed wetlands functioning. Bromide ions and tritium were used as a tracers to derive RTDs for two constructed wetlands: a reed bed with subsurface flow and a Lemna pond. Quantitative hydraulic characteristics (mean travel time of water, dispersion number) of the wetlands were evaluated from RTDs (Residence Time Distributions) by means of a mathematical model of waste water flow. (author)

Monitoramento do desenvolvimento de macrófitas aquáticas em laboratório por meio de imagens digitais

Directory of Open Access Journals (Sweden)

Felipe Aparecido Gabriel de Miranda

2014-06-01

Full Text Available Este trabalho teve como objetivo avaliar a precisão e a acurácia do processamento de imagens digitais terrestres e o desenvolvimento da macrófita aquática Lemna sp. Cerca de 1.281 plantas de lemna foram dispostas em três delimitadores, no interior de um tanque de piscicultura, e tiveram seu desenvolvimento monitorado durante quinze dias consecutivos, por meio de fotografias capturadas com uma câmera  fotográfica digital Samsung, sensor  1/2,3”, CCD com 12,3 mega-pixels. As fotografias foram processadas no programa computacional SPRING 5.1.6, sendo utilizado como classificador digital o algoritmo de maxiverossimilhança. A avaliação da precisão foi realizada pela comparação das áreas mapeadas e a acurácia por meio da exatidão do reconhecimento dos pixels classificados. Os resultados revelam o potencial da técnica no monitoramento diário da macrófita, bem como de sua distribuição espacial desta. Acrescenta-se que o método, além de ser de fácil realização, não provoca distúrbios nas plantas.

Duckweed as a low-cost soft sewage treatment system; La lenteja de agua como sistema blando de depuracion de aguas residuales de bajo coste

Energy Technology Data Exchange (ETDEWEB)

Cano Amador, A.J.; Coolado Lara, R.

1998-06-01

Different aquatic plants systems have been examined to be used in several stages of wastewater treatment process. The high growth rate, easy harvesting, high nutritional value and easy drying make duck weeds an interesting option. Some general characteristics of the treatment process (Suspended Solids, BOD, and nutrients removal), a typical treatment process unit, aspects of the geographical distributions of the family (Lemna sp), design criteria and efficiency and principal constraints are described. (Author) 22 refs.

Evaluation of Cumulative Ecosystem Response to Restoration Projects in the Lower Columbia River and Estuary, 2010

Science.gov (United States)

2012-05-01

LEOR Leersia oryzoides Rice cutgrass OBL Grass yes LEMI Lemna minor Duckweed OBL Herb yes LEVU Leucanthemum vulgare Oxeye daisy UPL Herb no yes...discharge today of 7,730 m3/s (Stanford et al. 2005). Historical flows, prior to river regulation by some 30 major dams and numerous minor dams...dominated by reed canarygrass. The changes between years were relatively minor , with one plot changing from 50% Lyngbye’s sedge and 50% reed

Comparative study on acute toxicity of tetracycline and tetracycline hydrochloride to three ciliates%四环素和盐酸四环素对3种纤毛虫急性毒性效应的比较研究

Institute of Scientific and Technical Information of China (English)

赵也; 张辰笈; 丁霜; 蔡兴隆; 潘旭明; 陈瑛

2017-01-01

In this paper,three ciliates were selected as experimental subjects,and a wide range of tetracycline and tetracycline hydrochloride were employed to carry out a comparative study of acute toxicity effects.It was showed that the 24 h medial lethal concentrations (24 h-LC50) of tetracycline to Stylonyciia lemnae, Paramecium caudatum and Stentor coeruleus were 171.025 16,52.361 25,199.356 32 mg/L,respectively;the 24 h lowest observed effect concentrations (24 h-LOEC) of tetracycline were 65.168 84,15.199 17,139.370 22 mg/L,respectively.On the other hand,the 24 h-LC50 of tetracycline hydrochloride to Stylonyciia lemnae, Paramecium caudatum and Stentor coeruleus were 44.485 66,50.245 83,33.777 69 mg/L,respectively;the 24 h-LOEC were 20.031 34,24.671 75,13.444 98 mg/L,respectively.The results showed that the tolerance of three ciliates to tetracycline was in the following order: Stentor coeruleus > Stylonyciia lemnae > Paramecium caudatum.The tolerance difference of the three ciliates to tetracycline hydrochloride was not significant.The acute toxicity of Paramecium caudatum to tetracycline antibiotics was low,so it was suitable to use ciliates for early monitoring and early warning of tetracycline antibiotic contamination in water environments.%以3种纤毛虫为受试原生动物,比较了四环素和盐酸四环素对3种纤毛虫的急性毒性效应.结果表明:四环素对浮萍棘尾虫(Stylonyciia lemnae)、尾草履虫(Paramecium caudatum)和天蓝喇叭虫(Stentor coeruleus)的24 h半致死质量浓度(24 h-LC50)分别为171.025 16、52.361 25、199.356 32 mg/L,24 h最低有影响质量浓度(24 h-LOEC)分别为65.168 84、15.199 17、139.370 22 mg/L;盐酸四环素对浮萍棘尾虫、尾草履虫和天蓝喇叭虫的24 h-LC50分别为44.485 66、50.245 83、33.777 69 mg/L,24 h-LOEC分别为20.031 34、24.671 75、13.444 98 mg/L.3种纤毛虫对四环素的耐受性强度为天蓝喇叭虫>浮萍棘尾虫>尾草履虫;3�

Effect of Aquatic Plants on Phosphorus Removal and Electrical Conductivity Decrease in Municipal Effluent

OpenAIRE

Sara Samimi Loghmani; Ali Abbaspour

2014-01-01

Phosphorus (P) is one of essential elements for living organisms, though its critical concentration in surface and ground waters impose a serious problem such as eutrophication. So treatment of polluted waters is required before discharging to water resources. One of effective ways to decrease water pollution is using aquatic plants. An experiment was conducted in pilots with a closed flowing system on two plants, elodea (egria densa) and duck weed (lemna minor) with four treatments and three...

Estructura comunitaria de diatomeas presentes en los sedimentos superficiales de ocho lagos andinos de Chile central Diatoms community structure in superficial sediments of eight Andean lakes of central Chile

Directory of Open Access Journals (Sweden)

INGRID E ALVIAL

2008-03-01

Full Text Available En este trabajo se analizó la estructura comunitaria de diatomeas depositadas en los sedimentos superficiales de ocho lagos andinos chilenos ubicados entre los 32°49' y 38°48' S. Se encontró un total de 99 taxa de diatomeas, distribuidos en 48 géneros. Del total de taxa, 74 fueron identificados a nivel de especie siendo todos ellos cosmopolitas a excepción de Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis y Pinnularia acidicola, entre otras, que están descritos solo para el Hemisferio Sur. Por otro lado, las muestras analizadas presentaron distinta composición florística de diatomeas. De esta manera, en los ensambles diatomológicos depositados en los sedimentos de las lagunas de altura Ocho, Huifa, Ensueño y Negra ubicadas sobre los 2.860 m del nivel del mar, abundaron especies bentónicas, típicas de aguas oligotróficas y acidas como Achnanthidium exiguum, Achnanthidium minutissimum, Encyonema minutum, Pinnularia acidicola y Planothidium lanceolatum. En los ensambles diatomológicos de los lagos Galletué, Icalma y Laja, ubicados bajo los 1.360 m del nivel del mar, abundaron diatomeas planctónicas, características de aguas alcalinas y mesotróficas como Asterionella formosa, Aulacoseira distans, Aulacoseira granulata, Cyclotella stelligera y Rhopalodia gibbaIn this research the taxonomic structure of diatoms in sediments of high mountain lakes was studied. These lakes are located in Chile between 32°49' and 38°48' S in the Andean Cordillera. A total of 99 diatom taxa distributed in 48 genera were identified and all this taxa are cosmopolitan excepting a Eunotia andinofrequens, Gomphonema punae, Pinnularia araucanensis and Pinnularia acidicola, which are know only for the Southern Hemisphere. The assemblages of diatoms were different in the studied lakes. So the high mountain lakes Ocho, Huifa, Ensueño and Negra, dominated benthic diatoms which are typical of oligotrophic and acid waters as Achnanthidium

Spatial distribution of microphytobenthos, meiofauna and macrofauna in the north-western Adriatic Sea: a synoptic study

Directory of Open Access Journals (Sweden)

Annalisa Franzo

2015-12-01

Full Text Available In view of the general paucity of integrated information on offshore benthic communities in the Adriatic Sea and given the vulnerability of this particular coastal system, microphytobenthos, meiofauna and macrofauna were synoptically investigated in front of the Emilia-Romagna coast (northern Adriatic Sea in September 2010 and March 2011. As required by the Marine Strategy Framework Directive, which extends its action beyond the territorial waters (within 12 nmi of the Member States, our findings could help to fill the gap of knowledge on the environmental status in offshore areas since the study was carried out also at >12 nmi from the coastline. In fact, sediment samples for the analysis of the benthic communities were collected from a 10-point-station grid that covered an area of about 400 km2 with water depths ranging from 13 to 50 m. The variability of the sediment grain size and other chemical variables in the sediment suggests the presence of two distinct environmental contexts that enhance the proliferation of different benthic communities. At the inshore stations (depth <20 m the higher sand percentages and the maxima of dissolved inorganic nitrogen concentrations indicate the presence of hydrodynamic perturbations and the influence of nutrient loads of terrestrial origin. Inshore, both meio- and macrofaunal communities were poorly structured and dominated by relatively more opportunistic taxa, such as nematodes and the bivalve Corbula gibba. Offshore stations (depth >20 m had muddier sediments, which likely exerted a greater retention of sediment-bound organic matter. These conditions seemed to favour benthic deposit feeders like meio- and macrofaunal annelids. Surprisingly, a conspicuous microphytobenthic community, mainly represented by the diatom Paralia sulcata, has been observed even at remarkable depths (~50 m opening new questions regarding the role of these organisms in dim-light conditions. Although the investigated benthic

Mineralization of Surfactants by Microbiota of Aquatic Plants

OpenAIRE

Federle, Thomas W.; Schwab, Burney S.

1989-01-01

The biodegradation of linear alkylbenzene sulfonate (LAS) and linear alcohol ethoxylate (LAE) by the microbiota associated with duckweed (Lemna minor) and the roots of cattail (Typha latifolia) was investigated. Plants were obtained from a pristine pond and a pond receiving wastewater from a rural laundromat. Cattail roots and duckweed plants were incubated in vessels containing sterile water amended with [14C]LAS, [14C]LAE, or 14C-labeled mixed amino acids (MAA). Evolution of 14CO2 was deter...

EFECTOS DEL MERCURIO SOBRE ALGUNAS PLANTAS ACUÁTICAS TROPICALES

OpenAIRE

Posada, Martha Isabel; Arroyave, María del Pilar

2006-01-01

El presente artículo es una descripción de los efectos del mercurio sobre algunas plantas acuáticas tropicales y sobre los ecosistemas donde habitan. Adicionalmente, se recomienda un protocolo para realizar pruebas de toxicidad con la lenteja de agua (Lemna minor) y se presentan los resultados de los preensayos con diferentes concentraciones de sales de mercurio en condiciones de laboratorio. Se encontró que la biodisponibilidad del mercurio depende de factores que facilitan la disolución del...

水盐环境梯度下野鸭湖湿地植物群落特征及其生态演替模式

Institute of Scientific and Technical Information of China (English)

宫兆宁; 赵文吉; 胡东

2009-01-01

按照水土环境差异及所受干扰情况将野鸭湖湿地自然保护区划分为三个实验区,系统分析了湿地生态系统的生物及其生境因子,三个样区的湿地植物群落呈现明显的分异特征.样区1植被具有典型的成带分布的特点,植物群落形成反映了水深和岸线的带状变化;样区2生境异质性小,建群种占绝对的优势,植物多样性低;样区3退水区域呈旱化趋势,植被呈现出草甸的性质,水盐梯度明显.基于湿地植物群落的分异特征,选择样区3从植物群落在空间维度上的组合这个角度,揭示湿地植物群落演替变化的时间过程,探索野鸭潮湿地植物群落的演替模式和演替机制.野鸭湖湿地常见植物群落随水分、盐分相互作用呈现相应的生态演替模式:水生沉水、浮水、漂浮植物群落(眼子菜+狐尾藻群落Comm.Potamogeton distinctus+Myriophyllum spiea-tum L.,槐叶苹+浮萍群落Comm.Salvinia natans+Lemna minor L.)、水生挺水植物群落(香蒲+芦苇群落Comm.Typha angustifolia+Phragmites australi)、沼生、湿生植物群落(球穗莎草群落Comm.Cyperus glomeratus L.,扁秆蔗草群落Comm.Scirpus planiculmis,绵毛酸模叶蓼群落Comm.Polygonum lapathifolium L.var.salicifolium sibth.)、盐生、中生植物群落(猪毛菜群落Comm.Salsola collina,柽柳群落Comm.Tamarixchinensis)、中旱生植物群落(红皮柳群落Comm.Saliz purpurea L.,牛鞭草群落Hemarthria altissima Stapf et C.E.Hubb).湿地生态演替模式及机制的分析,为湿地附近水域生态条件的改善,以及湿地恢复和植物物种选择提供了可以借鉴的方案.

/sup 60/Co accumulation by freshwater plants under natural conditions

Energy Technology Data Exchange (ETDEWEB)

Trapeznikov, A V; Trapeznikova, V N [AN SSSR, Sverdlovsk. Inst. Ehkologii Rastenij i Zhivotnykh

1979-03-01

In search for effective bioindicators of radioactive contamination of cooler-reservoirs in atomic power plants the accumulation of /sup 60/Co by four species of higher aquatic plants most widely distributed in the Urals was studied, namely by Elodea canadensis, Ceratophyllum demersum, Lemna minor and Potamogeton pectinatus. It is shown that such plants as Ceratophyllum demersum and Elodea canadensis having the accumulation coefficients of /sup 60/Co 33,500 and 21,500, respectively, can be recommended as bioindicators of this radionuclide in reservoirs contaminated with radioactive cobalt.

On 60Co accumulation by freshwater plants under natural conditions

International Nuclear Information System (INIS)

Trapeznikov, A.V.; Trapeznikova, V.N.

1979-01-01

In search for effective bioindicators of radioactive contamination of cooler-reservoirs in atomic power plants the accumulation of 60 Co by four species of higher aquatic plants most widely distributed in the Urals was studied, namely by Elodea canadensis, Ceratophyllum demersum, Lemna minor and Potamogeton pectinatus. It is shown that such plants as Ceratophyllum demersum and Elodea canadensis having the accumulation coefficients of 60 Co 33,500 and 21,500, respectively, can be recommended as bioindicators of this radionuclide in reservoirs contaminated with radioactive cobalt

Radiation induced mitotic delay and stimulation of growth

International Nuclear Information System (INIS)

Feldmann, A.

1974-01-01

The mechanisms responsible for the radiation induced mitotic delay and stimulation of growth are discussed in connection with the results of studies in Lemna minor and Lepidium sativum. The action of temperature seems to be of major importance. As many authors suggest that various chemical agents and slight intoxications also affect mitosis in a way similar to that induced by ionizing radiation, the radiation induced stimulation has lost its specific character and approaches might be found for further investigations of this phenomenon. (MG) [de

Valorização de landoltia punctata proveniente de tratamento de esgoto doméstico através de hidrólise enzimática visando a produção de etanol

OpenAIRE

Costa, Flávia Nunes

2014-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Alimentos, Florianópolis, 2014. A necessidade de se explorar novas fontes de energia renovável e limpa vem exigindo o desenvolvimento de biocombustíveis, por serem considerados uma alternativa promissora aos combustíveis tradicionais. Nesse contexto, as lemnas vêm ganhando interesse em pesquisas, por não competirem com culturas alimentícias e terras produtivas par...

Efficiency of removing nitrogen and phosphorous and effects on extracellular enzyme activity in water body by five hydrophytes%5种水生植物的脱氮除磷效果及其对水体胞外酶活的影响

Institute of Scientific and Technical Information of China (English)

汪文强; 王子芳; 高明

2016-01-01

To investigate the role of hydrophytes in the purification of eutrophic water bodies,Trapa quadrispinosa Roxb.,Eichhornia crassipes,Hydrocharis dubia (Bl.) Backer,Ipomoea aquatica Forsk,and Lemna minor L.were planted in treated water to compare their effects on purification and their influence on extracellular enzyme activity.The results showed that all hydrophytes performed well during the purification process.For total nitrogen (TN),the order of removal efficiency was Eichhornia crassipes (81.6％) ＞ Ipomoea aquatica Forsk (72.2％) ＞ Hydrocharis dubia (Bl.) Backer (68.4％) ＞ Trapa quadrispinosa Roxb.(65.8％) ＞ Lemna minor L.(60.2％),and for total phosphorous (TP) removal,the order was Eichhornia crassipes (95.0％) ＞ Ipomoea aquatica Forsk (89.7％) ＞ Hydrocharis dubia (Bl.) Backer (78.4％) ＞ Trapa quadrispinosa Roxb.(77.3％) ＞ Lemna minor L.(70.5％).All five hydrophytes could enhance the activity of extracellular enzymes,and the treatment involving E.crassipes showed the maximum range and peak urease activity (UA) and alkaline phosphatase activity (APA).The range and peak UA were 19.70 μg · mL-1 and 10.33 μg · mL-1,respectively,and for APA,they were 8.12 μg · mL-1 and 5.95 μg · mL-1.The range and peak UA and APA for Ipomoea aquatica Forsk were the next highest.UA and APA were significantly negatively correlated with the concentrations of both NH4-N and dissolved active phosphorus (SRP),and the correlations were between-0.853 and-0.992 and -0.813 and-0.994,respectively.Eichhornia crassipes and Ipomoea aquatica Forsk may work better than Trapa quadrispinosa Roxb,Hydrocharis dubia (Bl.) Backer and Lemna minor L.,and have potential for application in the purification of eutrophic water bodies.%利用静态小区实验研究了菱角(Trapa quadrispinosa Roxb.)、凤眼莲(Eichhornia crassipes.)、水鳖(Hydrocharis dubia (Bl.) Backer)、空心菜(Ipomoea aquatica Forsk)和青萍(Lemna minor L.)5�

Integrative assessment of biomarker responses in teleostean fishes exposed to glyphosate-based herbicide (Excel Mera 71

Directory of Open Access Journals (Sweden)

Sukhendu Dey

2016-12-01

Full Text Available Present study deals with the effects of glyphosate-based herbicide, Excel Mera 71 on Anabas testudineus, Heteropnestes fossilis and Oreochromis niloticus in field conditions (1.85 kg/ha based on anti-oxidative, metabolic and digestive responses. For this study following biomarkers viz., acetylcholinesterase (AChE, lipid peroxidation (LPO, catalase (CAT, glutathione-S-transferase (GST, alkaline phosphatase (ALP, aspartate aminotransferase (AST, alanine aminotransferase (ALT, amylase, lipase and protease were investigated in gill, stomach, intestine, liver, kidney, brain, muscle and spinal cord of the concerned fish species. Enzyme activities were significantly altered by glyphosate exposure after 30 days, these activities were tissue as well as species specific. The results suggested that these biomarkers could be used to assess the ecological risks of glyphosate on fish. Bioaccumulation factor (BAF studied in different aquatic natural macrophytes showed order of Alternanthera philoxeroides > Azolla pinnata > Lemna sp. (Minor > Lemna sp. (Major > Pistia stratiotes, while transfer factor (TF showed the order of Pistia stratiotes > Alternanthera philoxeroides > Lemna sp. Bioconcentration factor (BCF study showed maximum accumulation of glyphosate in liver, kidney or intestine, and minimum either in bone or stomach irrespective of fish species. An integrated biomarker response (IBR, which uses a battery of biomarkers to calculate the standardized scores for each biomarker responses ranging from physiological to biochemical/molecular responses, was evaluated by combining the multiple biomarkers into a single value to evaluate quantitatively the toxicological effects of glyphosate. In general, the multiple indices exhibited variations and A. testudineus was more affected than other fish species; maximum IBR value was observed for LPO and minimum in case of ALT. The order of integrated biomarkers caused by glyphosate treatment was

comparative study on the efficiency of Lemna minor L.

African Journals Online (AJOL)

Science World Journal Vol 10 (No 3) 2015 ... Pistiastratiotes In The Phytoremediation Of Refinery Waste Water. COMPARATIVE ... treatment to help in the determination of percentage ... research shows that Lemnaminoris the best plant to be.