Cargando…

Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay

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 tempo...

Descripción completa

Detalles Bibliográficos
Autores principales: Scherr, Claudia, Simon, Meinhard, Spranger, Jörg, Baumgartner, Stephan
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2008
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2518950/
https://www.ncbi.nlm.nih.gov/pubmed/18769541
http://dx.doi.org/10.1371/journal.pone.0003133
_version_ 1782158617227558912
author Scherr, Claudia
Simon, Meinhard
Spranger, Jörg
Baumgartner, Stephan
author_facet Scherr, Claudia
Simon, Meinhard
Spranger, Jörg
Baumgartner, Stephan
author_sort Scherr, Claudia
collection PubMed
description 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.
format Text
id pubmed-2518950
institution National Center for Biotechnology Information
language English
publishDate 2008
publisher Public Library of Science
record_format MEDLINE/PubMed
spelling pubmed-25189502008-09-04 Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay Scherr, Claudia Simon, Meinhard Spranger, Jörg Baumgartner, Stephan PLoS One Research Article 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. Public Library of Science 2008-09-04 /pmc/articles/PMC2518950/ /pubmed/18769541 http://dx.doi.org/10.1371/journal.pone.0003133 Text en Scherr et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Scherr, Claudia
Simon, Meinhard
Spranger, Jörg
Baumgartner, Stephan
Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay
title Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay
title_full Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay
title_fullStr Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay
title_full_unstemmed Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay
title_short Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay
title_sort test system stability and natural variability of a lemna gibba l. bioassay
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2518950/
https://www.ncbi.nlm.nih.gov/pubmed/18769541
http://dx.doi.org/10.1371/journal.pone.0003133
work_keys_str_mv AT scherrclaudia testsystemstabilityandnaturalvariabilityofalemnagibbalbioassay
AT simonmeinhard testsystemstabilityandnaturalvariabilityofalemnagibbalbioassay
AT sprangerjorg testsystemstabilityandnaturalvariabilityofalemnagibbalbioassay
AT baumgartnerstephan testsystemstabilityandnaturalvariabilityofalemnagibbalbioassay