Models with plants. microorganisms and virus for basic research in homeopathy

The chapter is a critical review about the research on homeopathy and plants. Only subsequent literature published after 1984 Scofield´s review has been considered. Therefore, the overview is divided in 4 sections: 1. models based on healthy plants, microorganisms, and viruses 2. models with impaired plants and microorganisms (abiotic stress), 3. phytopathological models using infected plants (biotic stress), 4. field trials. Plant- and microorganism-based experimentation appears suitable to study the effects of homeopathic treatments, making it possible to overcome some of the disadvantages of clinical trials: botanical and microbial trials do not present neither placebo effect nor ethical problems, and rely on a very cheap and almost inexhaustible source of biological material. Moreover, relatively simple model systems can be adopted so that a more direct treatment/effect relationship and large data samples for structured statistical analyses can be obtained. This is a very important feature because it allows a large number of experimental repetitions and external replications to be performed, useful for studying the problem of irreproducibility so often reported in homeopathic literature. In fact, one of the major challenges of homeopathic fundamental research today is the reproduction of preclinical studies that have shown significant effects of ultra highly diluted substances compared to control groups. The lack of reproducibility represents a crucial difficulty in testing homeopathy and has stimulated explanations of homeopathic treatment effects using complexity theory . Furthermore, since the main cell structures and functions are common in the majority of eucaryotes, plant and eucaryotic microbial bio-assays could be of interest also from a medical point of view, at least as complementary to clinical studies. Since the pioneering works of Kolisko on wheat germination and Junker on growth of mircroorganisms (paramecium, yeast, fungi), a number of experiments have been performed either with healthy organisms (various physiological aspects of growth) or with artificially diseased organisms, which may react more markedly to homeopathic treatments than healthy ones. In the latter case, the preliminary stress may be either abiotic, e.g. heavy metals, or biotic, e.g. fungal and viral pathogens or nematode infection. Research has also been carried out into the applicability of homeopathic principles to crop growth and disease control (agro-homeopathy): because of the extreme dilutions used, the environmental impact is low and such treatments are well suited to the holistic approach of sustainable agriculture. Unfortunately, as Scofield reported in an extensive critical review, there is little firm evidence to support the reliability of the reported results, due to poor experimental methodology and inadequate statistical analysis. Moreover, since there is no agricultural homeopathic pharmacopoeia, much work is required to find suitable remedies, potencies and dose levels.