Bar-Akiva, A., Institute of Horticulture, Agricultural Research Organization, Volcani Center, P.O.B. 6, Bet Dagan, 50250, Israel

3,3’5,5 Tetramethyl benzidine, 3-Amino-9-ethylcarbazol and chlorpromazine are suggested as alternatives for benzidine as H-donors in the peroxidase assay for diagnosing iron deficiency in plant leaves. Procedures with these reagents, which have been used successfully with citrus and other plants, are described. Copyright © 1984 by Marcel Dekker, Inc.