13 Inhibitory effects of methyl jasmonate on seed germination in maize Gen. Appl. plAnt physioloGy, 2007, 33 (1-2), 13-23 INHIBITORY EFFECTS OF METHYL JASMONATE ON SEED GERMINATION IN MAIZE (ZEA MAYS): EFFECT ON α-AMYLASE ACTIVITY AND ETHYLENE PRODUCTION A. Norastehnia 1 *, R. H. Sajedi 1 , M. Nojavan-Asghari 2 1 Department of Biology, Faculty of Science, University of Guilan, Rasht, Iran 2 Department of Biology, Faculty of Science, Urmia University, Urmia, Iran Received 10 February 2007 Summary. Methyl jasmonate (MeJA) inhibited germination and root elongation of maize seeds. There was a reciprocal relationship between MeJA concentrations applied and seed germination and radicle growth. Determination of α-amylase activity in crude extracts and zymogram analysis showed that both activity and content of the enzyme decreased in the presence of MeJA. In addition, a reduction in ethylene production which is necessary for seed germination was also observed upon MeJA treatment. Consequently, our data showed that decreased α-amylase activity and/or concentration as well as reduced ethylene production can play signiicant roles in the physiological and biochemical processes underlying inhibited seed germination and root elongation in maize under conditions of increased MeJA concentrations. Key words: methyl jasmonate, ethylene, α-amylase, maize. _____________ *Corresponding author, e-mail: norasteh@guilan.ac.ir