Recent Advances in the Use of Mitochondrial Activity of Fern Spores for the Evaluation of Acute Toxicity

One of the main concerns of current environmental toxicology is the low number of taxa used for standard bioassays. Ferns are the second largest group of vascular plants and are important components of numerous plant communities. Fern spores and gametophytes have long been recognized as useful models for plant research, since they constitute a naturally miniaturized and low-cost higher plant model. Mitochondria are the main energy source in eukaryotic cells, and any toxic damage to this organelle will affect the whole organism. The reduction of tetrazolium salts to water-insoluble coloured formazan salts by the NADH reductase complex (EC 1.6.5.3) has been used for more than 50 years as a measure of cell mitochondrial activity and viability in eukaryotic organisms. Here, the reduction of 2, 3, 5-triphenyltetrazolium chloride (TTC) by mitochondria is adapted and optimized to measure fern spore or gametophyte viability. A review of the recent literature using the fern spore bioassay reflects its utility for different environmental applications such as dose-response toxicological studies, environmental technology assessment or environmental monitoring. We conclude that this method constitutes a promising low-cost bioassay for toxicity of higher plant during development.