Norflurazon (0, 0.1, 0.2, 0.4, or 0.8 μ M) was applied concomitantly with desmethyl norflurazon (DMN), dichloropyridazinone (DCP), or the wrong isomer (WI) of norflurazon (0, 0.1, 0.2, 0.4, 0.8, 1.6, or 3.3 μ M) to wheat ( Triticum aestivum L. cv. Holley) grown in sand. After 14 days, carotenogenesis was inhibited by norflurazon and the inhibition was partially reversed by DMN, DCP, and WI. These reversals were observed at norflurazon concentrations ≤250 ≤ ∼0.823 μ M in the potting medium. Carotene contents in norflurazon (0.4 μ M) + no isomer, DMN, WI, or DCP (3.3 μ M) were 5.4, 40.7, 28.6, and 22.2%, respectively, of that present in the untreated control. Therefore, these materials might function as antidotes to soil residues of norflurazon. Partitioning of norflurazon and DMN among triolein (TG), phosphatidylcholine (PC), and water was attained via isopycnic centrifugation. Norflurazon was highly soluble in PC and accumulated in PC. DMN was not soluble in TG and was soluble in water and PC at a ratio of 0.5 Change in water solubility when norflurazon is demethylated to DMN may be the basis for lack of bleaching influence of DMN. DMN, DCP, and WI partially reversed norflurazon carotenogenesis inhibition in the concentration range of norflurazon associated with phytoene synthesis and the low range of norflurazon concentrations associated with phytoene desaturase.