Iron Toxicity to Fen Plant Species

The toxicity of ferrous iron to seedlings of 44 fen plant species was examined using 2-week screening experiments in solution culture. These were found to be more practicable than alternative methods which were tested. Growth measurements (including shoot and root length and dry weight, leaf size, and numbers and health of leaves) were made. Various tolerance indices were derived and compared, and one based on summation of standardized relative growth rates over a range of iron concentrations (Σ%RGR) was selected as being most appropriate. Standardization was achieved by expressing mean RGR for each treatment as a percentage of that in a low-iron control. An iron-tolerance species ranking was derived from this. Ward's classification (multivariate analysis) grouped the species into four main clusters on their standardized relative growth rate response (...)