Effects of fluorescent brighteners on growth and morphology of the red alga antithamnion kylinii

Four fluorescent brighteners (Fluorescent Brightener 28, Fluostain I, Fluostain II and Cellufluor) were examined with respect to their binding affinity, toxicity (their ability to stunt growth), and teratogenic effects on the red alga Antithamnion kylinii. Maximum binding occurred with FB-28 and F-II but these stains showed the greatest inhibition of growth when plants were exposed to concentrations of 0.01% for 30 min. Filaments incubated in low stain concentrations (0.0005% showed cell abnormalities with all stain types, with FB-28 producing the most extreme deformations of both intercalary and apical cells. The experiments suggest that extensive experimentation is required to develop protocols for vital cell wall stains that minimize toxicity and maximize binding.