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Reproducibility of the Effects of Homeopathically Potentised Argentum nitricum on the Growth of Lemna gibba L. in a Randomised and Blinded Bioassay
05 February 2018 (online)
Background: A previous study reported a significant statistical interaction between experiment date and treatment effect of Argentum nitricum 14×−30× on the growth rate of duckweed (Lemna gibba L.). The aim of the present study was to investigate the stability of the test system and intra-laboratory reproducibility of the effects found.
Methods: Duckweed was treated with Argentum nitricum potencies (14×–30×) as well as succussed and unsuccussed water controls. The outcome parameter area-related growth rate for day 0 to 7 was determined by a computerised image analysis system in two series of independent randomised and blinded experiments. Systematic negative control experiments were performed to investigate test system stability. Statistical analysis was performed with full two-way ANOVA and protected Fisher’s LSD test.
Results: In the first repetition series, we found a significant treatment effect (p = 0.0156), while in the second series, no effect was observed. The negative control experiments showed that the experimental system was stable. An a posteriori sub-group analysis concerning gibbosity revealed the importance of this growth state of Lemna gibba for successful reproduction of the statistically significant interaction in the original study; flat: no interaction (p = 0.7615); slight gibbosity: no interaction (p = 0.3557); medium gibbosity: significant interaction (p = 0.0308), high gibbosity: highly significant interaction (p = 0.0050).
Conclusion: With the original study design (disregarding gibbosity status of Lemna gibba), results of the original study could not be reproduced sensu stricto. We conclude that the growth state gibbosity is crucial for successful reproduction of the original study. Different physiological states of the test organisms used for bioassays for homeopathic basic research must carefully be considered.
Keywords: Duckweed (Lemna gibba L.), silver nitrate, gibbosity, reproduction study