Effects of Homeopathic Preparations of Mercurius corrosivus on the Growth Rate of Moderately Mercury-Stressed Duckweed Lemna gibba L
Tim Jäger, Sandra Würtenberger, Stephan Baumgartner
Background A bioassay with severely mercury-stressed duckweed (Lemna gibba L.) had
revealed growth-inhibiting effects of homeopathically potentised mercury(II) chloride
(Mercurius corrosivus, Merc-c.). We hypothesised that effects of potentised preparations
are dependent on the stress level of the organisms used in the bioassay. The aim of the
present investigation was to examine the response of duckweed to potentised Merc-c. at a
lower stress level.
Methods Duckweed was moderately stressed with 2.5mg/L mercury(II) chloride for
48 hours. Afterwards plants grewin either Merc-c. (seven different potency levels, 24x–30x)
or water controls (unsuccussed or succussed water) for 7 days. Growth rates of the frond
(leaf) area were determined using a computerised image-analysis system for day 0–3 and
3–7. Three independent experiments with potentisedMerc-c. and three systematic negative
control experiments were performed. All experiments were randomised and blinded.
Results Unsuccussed and succussed water did not significantly differ in their effects on
duckweed growth rate. The systematic negative control experiments did not yield any
significant effects, thus providing evidence for the stability of the experimental system.
Data from the two control groups and the seven treatment groups (Merc-c. 24x–30x) were
each pooled to increase statistical power. Duckweed growth rates for day 3–7 were
enhanced (p< 0.05) after application of Merc-c. compared with the controls. Growth rates
for day 0–3 were not influenced by the homeopathic preparations.
Conclusions Moderately mercury-stressed Lemna gibba L. yielded evidence of
growth-enhancing specific effects of Merc-c. 24x–30x in the second observation period
(day 3–7). This observation is complementary to previous experiments with severely
mercury-stressed duckweed, in which a decrease in growth was observed in the first
observation period (day 0–3). We hypothesise that the differing results are associated
with the level of stress intensity (moderate vs. severe).