Abstract: 【Objective】This study was to elucidate the effect of potassium chloride (KCl) on lignin metabolism in corn, and discuss the physiological mechanism of KCl suppressing corn stalk rot. 【Method】A field experiment combined with plant analysis experiment was conduct to study the changes in lignin content and activities of phenylalanine ammonia-lyase (PAL), tyrosine ammonia-lyase (TAL), peroxidase (POD) and cinnamyl alcohol dehydrogenase (CAD) in stalk pith tissue of susceptible and resistant corn cultivars before and after inoculation by Fursarium graminearum, and the effect of KCl on the above noted changes. 【Result】The results showed that original content in resistant corn（Jidan180）was lower than that of susceptible corn（Jidan327）, while the induced lignin content in resistant cultivar was more than that in susceptible cultivar. And KCl application decreased the original lignin content and increased the induced lignin content. The activities of PAL and TAL in stalk pith tissue were highest at 3 d after inoculation in the resistant cultivar, but increased slowly to a peak at 5 and 7 d after inoculation in the susceptible cultivar, respectively. KCl application decrease the background levels of PAL, TAL and POD activity, while increased the activities of PAL, TAL and POD(especially the maximum activity) in stalk pith tissue of the resistant and susceptible corns following pathogen invasion. In addition, KCl application enhanced CAD activity in the resistant and susceptible corns before and after inoculation. 【Conclusion】In conclusion, KCl stimulated the rapid expression of PAL, TAL, POD and CAD activities in both resistant and susceptible corns after inoculation, increased the induced lignin content, and then enhanced the resistance of corn to stalk rot.

Key words: Potassium chloride, Lignin metabolism, Enzyme activity, Corn stalk rot, Resistance mechanism