The lysine analogs S-2-aminoethyl-L-cysteine (AEC) and DL-Δ-hydroxylysine (DHL) caused severe growth inhibition in dark-grown oat seedlings (Avena sativa L. and A. nuda L.) at similar concentrations while L-lysine methyl ester (LME) had little effect. Lysine, arginine, and ornithine reversed the