Abstract: The response to pathogen mediated by salicylic acid (SA) in plant required not only a high level of SA but also an effective SA signal perception and transduction mechanism. The maize ( Zea mays L. ) leaves contained extremely low level of free SA. Catalases from different maize tissues also exhibited different sensitivity to SA. Catalases from leaves were sensitive to SA, but roots contained SA-insensitive eatalases, indicating the presence of different tissue specific catalase isozymes. It seems that there is such an effective mechanism signal sensitization and signal conductance in maize leaves just the same as in tabacco and Arabidopsis. The ability of resistance to Helminthosporium turcicum Pass. in maize leaves can be enhanced by SA.

Key words: Maize, Salicylic acid, Catalase, Systemic acquired resistance