Fluridone is an herbicide.^1,2,3,4It inhibits phytoene desaturase (K_i= 0.03 µM), an enzyme involved in carotenoid biosynthesis.¹Fluridone (50 and 100 µM) decreases β-carotene levels and induces accumulation of phytofluene and phytoene inT. aestivumseedlings grown in the dark.²It reduces levels of the plant hormone abscisic acid in hydrated and dehydratedV. fabaleaves when used at a concentration of 10 µM.³Fluridone is cytotoxic to the cyanobacteriumAnacystis nidulans(LC₅₀= 0.125 µM) and has acute toxicity against several species of invertebrates and fish (median LC₅₀s = 4.3 and 10.4 mg/L, respectively).^1,4Formulations containing fluridone have been used as aquatic herbicides.

1.Chamovitz, D., Sandmann, G., and Hirschberg, J.Molecular and biochemical characterization of herbicide-resistant mutants of cyanobacteria reveals that phytoene desaturation is a rate-limiting step in carotenoid biosynthesisJ. Biol. Chem.268(23)17348-17353(1993) 2.Bartels, P.G., and Watson, C.W.Inhibition of carotenoid synthesis by fluridone and norflurazonWeed Sci.26(2)198-203(1978) 3.Popova, L.P., and Riddle, K.A.Development and accumulation of ABA in fluridone-treated and drought-stressed Vicia faba plants under different light conditionsPhysiol. Plantarum98(4)791-797(1996) 4.Hamelink, J.L., Buckler, D.R., Mayer, F.L., et al.Toxicity of fluridone to aquatic invertebrates and fishEnviron. Toxicol. Chem.5(1)87-94(1986)