MATERIALS AND METHODS
Seed germination and radicle growth
Maize (Zea mays L. genotype single cross 704) seeds were obtained from Iranian agricultural research center (2004). The seeds were washed with distilled water and sterilized with 5% (w/v) sodium hypochlorite solution for 10 min. After that seeds were incubated in 15 ml 5% ethanol (v/v) (control) or different concentrations of MeJA (50, 100, 200 and 500 μM) in 15 cm Petri dishes at 25 0C in darkness. All different concentrations of MeJA were dissolved in 5% ethanol (v/v) as a solvent. After 4 days the percentage of seed germination was determined. A seed was regarded as germinated when its radicle had protruded about 1mm from the seed coat. The lengths of radicles were also measured.