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Erdal Öbek - One of the best experts on this subject based on the ideXlab platform.

  • Removal of tetracycline and the degradation products by Lemna Gibba L. exposed to secondary effluents
    Environmental Progress, 2015
    Co-Authors: Murat Topal, Erdal Öbek, Gülşad Uslu Şenel, E. Işıl Arslan Topal
    Abstract:

    The aims of this study were the determination of (i) tetracycline (TC) and the degradation products removal efficiency of Elazig Municipal Wastewater Treatment Plant (ii) the removal of TC and the degradation products in a pilot scale constructed wetland reactor planted with Lemna Gibba L., which takes the effluent of the treatment plant (iii) the comparison of the removal of TC and the degradation products in the treatment plant and pilot scale reactor and (iv) the contribution of the planted rector to the treatment plant in terms of removal of TC and the degradation products. For these aims, composite samples were taken from both the influent and effluent of the treatment plant and the pilot scale reactor and then TC and degradation products analyses were done by UFLC/MS-MS. TC, 4-epianhydrotetacycline (EATC) and anhydrotetracycline (ATC) removal efficiencies of the treatment plant were determined as 79.65, 64.42, and 80.19%, respectively. 4-epitetracycline (ETC) removal efficiency was not seen. TC, ETC, EATC, and ATC removal efficiencies in the planted reactor were obtained as 55.42, 89.85, 39.31 and 63.42%, respectively. The data obtained from the results of the analyses were also evaluated statistically. As a result, it was seen that Lemna Gibba L. was efficient to remove TC and the degradation products and improved the treatment plant TC and the degradation products removal efficiency. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1311–1321, 2015

  • potential of Lemna Gibba l and Lemna minor l for accumulation of boron from secondary effluents
    Ecological Engineering, 2014
    Co-Authors: şule Yuksel Tatar, Erdal Öbek
    Abstract:

    Aquatic plants are quite effective in removal of pollutants which cannot be removed in secondary treatment. Lemna Gibba L. and Lemna minor L. among the aquatic plants were investigated for the removal of boron from the secondary waste water. Differences in Boron uptake were seen in the chosen aquatic macrophytes. Although boron is at low concentration in water, the bioaccumulated concentrations in Lemna minor L. and Lemna Gibba L. were at high levels of between 140 mg Bg 140 –1and 274 mgB g−1, and 381 mgB g−1 523 mgB g−1 respectively. From these results, it was understood that Lemna Gibba L. is more prone to accumulate boron compared to Lemna minor L.

  • the accumulation of silver and gold in Lemna Gibba l exposed to secondary effluents
    Chemie Der Erde-geochemistry, 2012
    Co-Authors: Ahmet Sasmaz, Erdal Öbek
    Abstract:

    Aquatic plants are used as a practical and effective method to remove toxic metals from secondary-treated municipal wastewater. In this study, Lemna Gibba was investigated for its capacity to remove silver (Ag) and gold (Au) from secondary effluents. L. Gibba was collected from a natural lake and then acclimatized to the effluent in situ. The concentration of toxic elements in the plant material was monitored as a function of time over 7 days. L. Gibba accumulated significant amounts of Ag and Au for six days from initiation of the experimental study. The highest accumulations were 2303% for Ag and 247% for Au. However, after six days, the rate of Ag and Au accumulation in L. Gibba declined, as saturation levels had been reached in the plant tissues. The metal accumulating property of L. Gibba can also be commercially exploited to recover Au and Ag from wastewater and mining wastes.

  • Bioaccumulation of aluminum by Lemna Gibba L. from secondary treated municipal wastewater effluents.
    Bulletin of Environmental Contamination and Toxicology, 2011
    Co-Authors: Erdal Öbek, Ahmet Sasmaz
    Abstract:

    In this study, Lemna Gibba as a sample aquatic plant was used to remove Al from a municipal secondary waste water effluence. Lemna Gibba was acclimatized to the effluent in situ. The concentration of Al in the plant samples was examined for 7 days. Lemna Gibba accumulated 500 μg Al g−1 on the first day and reached saturation level with an increase of 100 μg g−1 on the second day. The results indicated that Lemna Gibba can be used as an effective aquatic plant at low costs for the treatment of municipal secondary waste water effluent. It was also noted that the plant should be harvested every 2 days for obtaining maximum efficiency.

  • the accumulation of arsenic uranium and boron in Lemna Gibba l exposed to secondary effluents
    Ecological Engineering, 2009
    Co-Authors: Ahmet Sasmaz, Erdal Öbek
    Abstract:

    Abstract Aquatic plants are used as a practical and effective method to remove toxic elements from secondary-treated municipal wastewater. In this study, Lemna Gibba was investigated for its capacity to remove uranium, arsenic, and boron from secondary effluents. L. Gibba was collected from a natural lake in Elazig, Turkey, then acclimatized to the effluent in situ. The concentration of toxic elements in the plant material was monitored as a function of time for 7 days. L. Gibba significantly accumulated the toxic elements, particularly in the first 2 days. Arsenic, uranium, and boron were accumulated in the highest concentrations (133%, 122%, and 40%, respectively). However, in the following days, accumulation levels showed both increases and decreases, most probably due to L. Gibba reaching saturation levels.

Ahmet Sasmaz - One of the best experts on this subject based on the ideXlab platform.

  • removal of cr ni and co in the water of chromium mining areas by using Lemna Gibba l and Lemna minor l
    Water and Environment Journal, 2016
    Co-Authors: Ahmet Sasmaz, Ibrahim Mete Dogan, Merve Sasmaz
    Abstract:

    This study investigated the use of Lemna Gibba and Lemna minor plant species to absorb Cr, Ni and Co from Alacakaya mining area water. Lemna Gibba and L. minor were separately placed to feed into two reactors. Water and plant samples were collected for eight consecutive days, and the pH, electric conductivity and temperature of the water were measured. The plants were washed, dried and burned at 300°C for 24 h in a drying oven. The samples were then analysed by ICP-MS (inductively coupled plasma mass spectroscopy) for concentrations of Cr, Ni and Co, which were 1.2, 0.9 and 0.5 μg L−1 respectively. On Day 8, the determined uptake of L. Gibba and L. minor were: 196 and 398% for Cr; 307 and 1473% for Ni; and 166 and 223% for Co respectively. Lemna Gibba and L. minor were thus effective in absorbing Cr, Ni and Co from mining water.

  • the accumulation of silver and gold in Lemna Gibba l exposed to secondary effluents
    Chemie Der Erde-geochemistry, 2012
    Co-Authors: Ahmet Sasmaz, Erdal Öbek
    Abstract:

    Aquatic plants are used as a practical and effective method to remove toxic metals from secondary-treated municipal wastewater. In this study, Lemna Gibba was investigated for its capacity to remove silver (Ag) and gold (Au) from secondary effluents. L. Gibba was collected from a natural lake and then acclimatized to the effluent in situ. The concentration of toxic elements in the plant material was monitored as a function of time over 7 days. L. Gibba accumulated significant amounts of Ag and Au for six days from initiation of the experimental study. The highest accumulations were 2303% for Ag and 247% for Au. However, after six days, the rate of Ag and Au accumulation in L. Gibba declined, as saturation levels had been reached in the plant tissues. The metal accumulating property of L. Gibba can also be commercially exploited to recover Au and Ag from wastewater and mining wastes.

  • Bioaccumulation of aluminum by Lemna Gibba L. from secondary treated municipal wastewater effluents.
    Bulletin of Environmental Contamination and Toxicology, 2011
    Co-Authors: Erdal Öbek, Ahmet Sasmaz
    Abstract:

    In this study, Lemna Gibba as a sample aquatic plant was used to remove Al from a municipal secondary waste water effluence. Lemna Gibba was acclimatized to the effluent in situ. The concentration of Al in the plant samples was examined for 7 days. Lemna Gibba accumulated 500 μg Al g−1 on the first day and reached saturation level with an increase of 100 μg g−1 on the second day. The results indicated that Lemna Gibba can be used as an effective aquatic plant at low costs for the treatment of municipal secondary waste water effluent. It was also noted that the plant should be harvested every 2 days for obtaining maximum efficiency.

  • the accumulation of arsenic uranium and boron in Lemna Gibba l exposed to secondary effluents
    Ecological Engineering, 2009
    Co-Authors: Ahmet Sasmaz, Erdal Öbek
    Abstract:

    Abstract Aquatic plants are used as a practical and effective method to remove toxic elements from secondary-treated municipal wastewater. In this study, Lemna Gibba was investigated for its capacity to remove uranium, arsenic, and boron from secondary effluents. L. Gibba was collected from a natural lake in Elazig, Turkey, then acclimatized to the effluent in situ. The concentration of toxic elements in the plant material was monitored as a function of time for 7 days. L. Gibba significantly accumulated the toxic elements, particularly in the first 2 days. Arsenic, uranium, and boron were accumulated in the highest concentrations (133%, 122%, and 40%, respectively). However, in the following days, accumulation levels showed both increases and decreases, most probably due to L. Gibba reaching saturation levels.

Stephan Baumgartner - One of the best experts on this subject based on the ideXlab platform.

  • development of a test system for homeopathic preparations using impaired duckweed Lemna Gibba l
    Journal of Alternative and Complementary Medicine, 2011
    Co-Authors: Tim Jager, Claudia Scherr, Meinhard Simon, Peter Heusser, Stephan Baumgartner
    Abstract:

    Abstract Objectives: A bioassay with arsenic-stressed duckweed (Lemna Gibba L.) was developed to study potentially regulative effects of homeopathic preparations. We compared potentized substances (nine different potency levels between 17 x and 33 x ) with two controls (unsuccussed and succussed water) regarding their influence on number- and area-related growth rate and color of fronds (leaves). Screening included 11 potentized substances: Arsenicum album, gibberellic acid, nosode, arsenic(V), phosphorus, Conchae, Acidum picrinicum, Argentum nitricum, Crotalus horridus, Hepar sulfuris, and Mercurius vivus naturalis. Design: Duckweed was stressed with arsenic(V) for 48 hours. Afterwards, plants grew in either potentized substances or water controls for 6 days. Growth rate and color of fronds were determined with a computerized image analysis system for different time intervals (days 0–2, 2–6, 0–6). A systematic negative control experiment with unsuccussed water was used to investigate the stability of the...

  • effects of potentised substances on growth rate of the water plant Lemna Gibba l
    Complementary Therapies in Medicine, 2009
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    OBJECTIVES: This study investigated, whether the growth rate of Lemna Gibba L. (duckweed) can be influenced by the application of homeopathic potencies of gibberellic acid, kinetin, argentum nitricum, and Lemna minor. METHODS: Duckweed was grown in either potencies (14x-30x, decimal steps) or water controls (unsuccussed and succussed) over seven days. Frond (leaf-like structure) growth was measured using a non-destructive image analysis system. Growth rates were calculated for three time intervals (0-7, 0-3, 3-7 days). Five to six independent, randomized and blinded experiments were analysed for each of the four tested substances. Water control experiments were performed repeatedly to test the reliability of the experimental set-up (systematic negative controls). RESULTS: The systematic negative control experiments did not yield any significant effects. Hence, false positive results could be excluded. The test system had a low coefficient of variation (1.5%). Out of the four tested substances gibberellic acid had the most pronounced effect (p=0.0002, F-test) on the main outcome parameter frond growth rate (r(area) day 0-7). Potency levels 15x, 17x, 18x, 23x and 24x reduced growth rate of Lemna Gibba (p<0.05 against the pooled water control, LSD test). CONCLUSIONS: Lemna Gibba may be considered as a suitable test organism for further studies on the efficacy of homeopathic potencies. Evidence accumulates, that adjacent potency levels may strongly differ in their biological activity. Potential consequences for therapeutical application might be worth investigating.

  • Effects of potentised substances on growth rate of the water plant Lemna Gibba L.
    Complementary Therapies in Medicine, 2009
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    OBJECTIVES: This study investigated, whether the growth rate of Lemna Gibba L. (duckweed) can be influenced by the application of homeopathic potencies of gibberellic acid, kinetin, argentum nitricum, and Lemna minor. METHODS: Duckweed was grown in either potencies (14x-30x, decimal steps) or water controls (unsuccussed and succussed) over seven days. Frond (leaf-like structure) growth was measured using a non-destructive image analysis system. Growth rates were calculated for three time intervals (0-7, 0-3, 3-7 days). Five to six independent, randomized and blinded experiments were analysed for each of the four tested substances. Water control experiments were performed repeatedly to test the reliability of the experimental set-up (systematic negative controls). RESULTS: The systematic negative control experiments did not yield any significant effects. Hence, false positive results could be excluded. The test system had a low coefficient of variation (1.5%). Out of the four tested substances gibberellic acid had the most pronounced effect (p=0.0002, F-test) on the main outcome parameter frond growth rate (r(area) day 0-7). Potency levels 15x, 17x, 18x, 23x and 24x reduced growth rate of Lemna Gibba (p

  • test system stability and natural variability of a Lemna Gibba l bioassay
    PLOS ONE, 2008
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    Background: In ecotoxicological and environmental studies Lemna spp. are used as test organisms due to their small size, rapid predominantly vegetative reproduction, easy handling and high sensitivity to various chemicals. However, there is not much information available concerning spatial and temporal stability of experimental set-ups used for Lemna bioassays, though this is essential for interpretation and reliability of results. We therefore investigated stability and natural variability of a Lemna Gibba bioassay assessing area-related and frond number-related growth rates under controlled laboratory conditions over about one year. Methology/Principal Findings: Lemna Gibba L. was grown in beakers with Steinberg medium for one week. Area-related and frond number-related growth rates (r(area) and r(num)) were determined with a non-destructive image processing system. To assess inter-experimental stability, 35 independent experiments were performed with 10 beakers each in the course of one year. We observed changes in growth rates by a factor of two over time. These did not correlate well with temperature or relative humidity in the growth chamber. In order to assess intra-experimental stability, we analysed six systematic negative control experiments (nontoxicant tests) with 96 replicate beakers each. Evaluation showed that the chosen experimental set-up was stable and did not produce false positive results. The coefficient of variation was lower for r(area) (2.99%) than for r(num) (4.27%). Conclusions/Significance: It is hypothesised that the variations in growth rates over time under controlled conditions are partly due to endogenic periodicities in Lemna Gibba. The relevance of these variations for toxicity investigations should be investigated more closely. Area-related growth rate seems to be more precise as non-destructive calculation parameter than number-related growth rate. Furthermore, we propose two new validity criteria for Lemna Gibba bioassays: variability of average specific and section-by-section segmented growth rate, complementary to average specific growth rate as the only validity criterion existing in guidelines for duckweed bioassays.

  • duckweed Lemna Gibba l as a test organism for homeopathic potencies
    Journal of Alternative and Complementary Medicine, 2007
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    ABSTRACT Objectives: A bioassay with duckweed (Lemna Gibba L.) was used to study the effects of homeopathic potencies on the plant's growth rate. Screening included 12 substances: argentum nitricum...

Claudia Scherr - One of the best experts on this subject based on the ideXlab platform.

  • development of a test system for homeopathic preparations using impaired duckweed Lemna Gibba l
    Journal of Alternative and Complementary Medicine, 2011
    Co-Authors: Tim Jager, Claudia Scherr, Meinhard Simon, Peter Heusser, Stephan Baumgartner
    Abstract:

    Abstract Objectives: A bioassay with arsenic-stressed duckweed (Lemna Gibba L.) was developed to study potentially regulative effects of homeopathic preparations. We compared potentized substances (nine different potency levels between 17 x and 33 x ) with two controls (unsuccussed and succussed water) regarding their influence on number- and area-related growth rate and color of fronds (leaves). Screening included 11 potentized substances: Arsenicum album, gibberellic acid, nosode, arsenic(V), phosphorus, Conchae, Acidum picrinicum, Argentum nitricum, Crotalus horridus, Hepar sulfuris, and Mercurius vivus naturalis. Design: Duckweed was stressed with arsenic(V) for 48 hours. Afterwards, plants grew in either potentized substances or water controls for 6 days. Growth rate and color of fronds were determined with a computerized image analysis system for different time intervals (days 0–2, 2–6, 0–6). A systematic negative control experiment with unsuccussed water was used to investigate the stability of the...

  • effects of potentised substances on growth rate of the water plant Lemna Gibba l
    Complementary Therapies in Medicine, 2009
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    OBJECTIVES: This study investigated, whether the growth rate of Lemna Gibba L. (duckweed) can be influenced by the application of homeopathic potencies of gibberellic acid, kinetin, argentum nitricum, and Lemna minor. METHODS: Duckweed was grown in either potencies (14x-30x, decimal steps) or water controls (unsuccussed and succussed) over seven days. Frond (leaf-like structure) growth was measured using a non-destructive image analysis system. Growth rates were calculated for three time intervals (0-7, 0-3, 3-7 days). Five to six independent, randomized and blinded experiments were analysed for each of the four tested substances. Water control experiments were performed repeatedly to test the reliability of the experimental set-up (systematic negative controls). RESULTS: The systematic negative control experiments did not yield any significant effects. Hence, false positive results could be excluded. The test system had a low coefficient of variation (1.5%). Out of the four tested substances gibberellic acid had the most pronounced effect (p=0.0002, F-test) on the main outcome parameter frond growth rate (r(area) day 0-7). Potency levels 15x, 17x, 18x, 23x and 24x reduced growth rate of Lemna Gibba (p<0.05 against the pooled water control, LSD test). CONCLUSIONS: Lemna Gibba may be considered as a suitable test organism for further studies on the efficacy of homeopathic potencies. Evidence accumulates, that adjacent potency levels may strongly differ in their biological activity. Potential consequences for therapeutical application might be worth investigating.

  • Effects of potentised substances on growth rate of the water plant Lemna Gibba L.
    Complementary Therapies in Medicine, 2009
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    OBJECTIVES: This study investigated, whether the growth rate of Lemna Gibba L. (duckweed) can be influenced by the application of homeopathic potencies of gibberellic acid, kinetin, argentum nitricum, and Lemna minor. METHODS: Duckweed was grown in either potencies (14x-30x, decimal steps) or water controls (unsuccussed and succussed) over seven days. Frond (leaf-like structure) growth was measured using a non-destructive image analysis system. Growth rates were calculated for three time intervals (0-7, 0-3, 3-7 days). Five to six independent, randomized and blinded experiments were analysed for each of the four tested substances. Water control experiments were performed repeatedly to test the reliability of the experimental set-up (systematic negative controls). RESULTS: The systematic negative control experiments did not yield any significant effects. Hence, false positive results could be excluded. The test system had a low coefficient of variation (1.5%). Out of the four tested substances gibberellic acid had the most pronounced effect (p=0.0002, F-test) on the main outcome parameter frond growth rate (r(area) day 0-7). Potency levels 15x, 17x, 18x, 23x and 24x reduced growth rate of Lemna Gibba (p

  • test system stability and natural variability of a Lemna Gibba l bioassay
    PLOS ONE, 2008
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    Background: In ecotoxicological and environmental studies Lemna spp. are used as test organisms due to their small size, rapid predominantly vegetative reproduction, easy handling and high sensitivity to various chemicals. However, there is not much information available concerning spatial and temporal stability of experimental set-ups used for Lemna bioassays, though this is essential for interpretation and reliability of results. We therefore investigated stability and natural variability of a Lemna Gibba bioassay assessing area-related and frond number-related growth rates under controlled laboratory conditions over about one year. Methology/Principal Findings: Lemna Gibba L. was grown in beakers with Steinberg medium for one week. Area-related and frond number-related growth rates (r(area) and r(num)) were determined with a non-destructive image processing system. To assess inter-experimental stability, 35 independent experiments were performed with 10 beakers each in the course of one year. We observed changes in growth rates by a factor of two over time. These did not correlate well with temperature or relative humidity in the growth chamber. In order to assess intra-experimental stability, we analysed six systematic negative control experiments (nontoxicant tests) with 96 replicate beakers each. Evaluation showed that the chosen experimental set-up was stable and did not produce false positive results. The coefficient of variation was lower for r(area) (2.99%) than for r(num) (4.27%). Conclusions/Significance: It is hypothesised that the variations in growth rates over time under controlled conditions are partly due to endogenic periodicities in Lemna Gibba. The relevance of these variations for toxicity investigations should be investigated more closely. Area-related growth rate seems to be more precise as non-destructive calculation parameter than number-related growth rate. Furthermore, we propose two new validity criteria for Lemna Gibba bioassays: variability of average specific and section-by-section segmented growth rate, complementary to average specific growth rate as the only validity criterion existing in guidelines for duckweed bioassays.

  • duckweed Lemna Gibba l as a test organism for homeopathic potencies
    Journal of Alternative and Complementary Medicine, 2007
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    ABSTRACT Objectives: A bioassay with duckweed (Lemna Gibba L.) was used to study the effects of homeopathic potencies on the plant's growth rate. Screening included 12 substances: argentum nitricum...

Meinhard Simon - One of the best experts on this subject based on the ideXlab platform.

  • development of a test system for homeopathic preparations using impaired duckweed Lemna Gibba l
    Journal of Alternative and Complementary Medicine, 2011
    Co-Authors: Tim Jager, Claudia Scherr, Meinhard Simon, Peter Heusser, Stephan Baumgartner
    Abstract:

    Abstract Objectives: A bioassay with arsenic-stressed duckweed (Lemna Gibba L.) was developed to study potentially regulative effects of homeopathic preparations. We compared potentized substances (nine different potency levels between 17 x and 33 x ) with two controls (unsuccussed and succussed water) regarding their influence on number- and area-related growth rate and color of fronds (leaves). Screening included 11 potentized substances: Arsenicum album, gibberellic acid, nosode, arsenic(V), phosphorus, Conchae, Acidum picrinicum, Argentum nitricum, Crotalus horridus, Hepar sulfuris, and Mercurius vivus naturalis. Design: Duckweed was stressed with arsenic(V) for 48 hours. Afterwards, plants grew in either potentized substances or water controls for 6 days. Growth rate and color of fronds were determined with a computerized image analysis system for different time intervals (days 0–2, 2–6, 0–6). A systematic negative control experiment with unsuccussed water was used to investigate the stability of the...

  • effects of potentised substances on growth rate of the water plant Lemna Gibba l
    Complementary Therapies in Medicine, 2009
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    OBJECTIVES: This study investigated, whether the growth rate of Lemna Gibba L. (duckweed) can be influenced by the application of homeopathic potencies of gibberellic acid, kinetin, argentum nitricum, and Lemna minor. METHODS: Duckweed was grown in either potencies (14x-30x, decimal steps) or water controls (unsuccussed and succussed) over seven days. Frond (leaf-like structure) growth was measured using a non-destructive image analysis system. Growth rates were calculated for three time intervals (0-7, 0-3, 3-7 days). Five to six independent, randomized and blinded experiments were analysed for each of the four tested substances. Water control experiments were performed repeatedly to test the reliability of the experimental set-up (systematic negative controls). RESULTS: The systematic negative control experiments did not yield any significant effects. Hence, false positive results could be excluded. The test system had a low coefficient of variation (1.5%). Out of the four tested substances gibberellic acid had the most pronounced effect (p=0.0002, F-test) on the main outcome parameter frond growth rate (r(area) day 0-7). Potency levels 15x, 17x, 18x, 23x and 24x reduced growth rate of Lemna Gibba (p<0.05 against the pooled water control, LSD test). CONCLUSIONS: Lemna Gibba may be considered as a suitable test organism for further studies on the efficacy of homeopathic potencies. Evidence accumulates, that adjacent potency levels may strongly differ in their biological activity. Potential consequences for therapeutical application might be worth investigating.

  • Effects of potentised substances on growth rate of the water plant Lemna Gibba L.
    Complementary Therapies in Medicine, 2009
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    OBJECTIVES: This study investigated, whether the growth rate of Lemna Gibba L. (duckweed) can be influenced by the application of homeopathic potencies of gibberellic acid, kinetin, argentum nitricum, and Lemna minor. METHODS: Duckweed was grown in either potencies (14x-30x, decimal steps) or water controls (unsuccussed and succussed) over seven days. Frond (leaf-like structure) growth was measured using a non-destructive image analysis system. Growth rates were calculated for three time intervals (0-7, 0-3, 3-7 days). Five to six independent, randomized and blinded experiments were analysed for each of the four tested substances. Water control experiments were performed repeatedly to test the reliability of the experimental set-up (systematic negative controls). RESULTS: The systematic negative control experiments did not yield any significant effects. Hence, false positive results could be excluded. The test system had a low coefficient of variation (1.5%). Out of the four tested substances gibberellic acid had the most pronounced effect (p=0.0002, F-test) on the main outcome parameter frond growth rate (r(area) day 0-7). Potency levels 15x, 17x, 18x, 23x and 24x reduced growth rate of Lemna Gibba (p

  • test system stability and natural variability of a Lemna Gibba l bioassay
    PLOS ONE, 2008
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    Background: In ecotoxicological and environmental studies Lemna spp. are used as test organisms due to their small size, rapid predominantly vegetative reproduction, easy handling and high sensitivity to various chemicals. However, there is not much information available concerning spatial and temporal stability of experimental set-ups used for Lemna bioassays, though this is essential for interpretation and reliability of results. We therefore investigated stability and natural variability of a Lemna Gibba bioassay assessing area-related and frond number-related growth rates under controlled laboratory conditions over about one year. Methology/Principal Findings: Lemna Gibba L. was grown in beakers with Steinberg medium for one week. Area-related and frond number-related growth rates (r(area) and r(num)) were determined with a non-destructive image processing system. To assess inter-experimental stability, 35 independent experiments were performed with 10 beakers each in the course of one year. We observed changes in growth rates by a factor of two over time. These did not correlate well with temperature or relative humidity in the growth chamber. In order to assess intra-experimental stability, we analysed six systematic negative control experiments (nontoxicant tests) with 96 replicate beakers each. Evaluation showed that the chosen experimental set-up was stable and did not produce false positive results. The coefficient of variation was lower for r(area) (2.99%) than for r(num) (4.27%). Conclusions/Significance: It is hypothesised that the variations in growth rates over time under controlled conditions are partly due to endogenic periodicities in Lemna Gibba. The relevance of these variations for toxicity investigations should be investigated more closely. Area-related growth rate seems to be more precise as non-destructive calculation parameter than number-related growth rate. Furthermore, we propose two new validity criteria for Lemna Gibba bioassays: variability of average specific and section-by-section segmented growth rate, complementary to average specific growth rate as the only validity criterion existing in guidelines for duckweed bioassays.

  • duckweed Lemna Gibba l as a test organism for homeopathic potencies
    Journal of Alternative and Complementary Medicine, 2007
    Co-Authors: Claudia Scherr, Jorg Spranger, Meinhard Simon, Stephan Baumgartner
    Abstract:

    ABSTRACT Objectives: A bioassay with duckweed (Lemna Gibba L.) was used to study the effects of homeopathic potencies on the plant's growth rate. Screening included 12 substances: argentum nitricum...