Abstract: Riboflavin is a novel elicitor of systemic acquired resistance ( SAR) in plants and activates a distinctdefense signaling pathway from several known ones． Here，we analyzed the role of riboflavin in wheat seedlings( Yangmai 16) defense against powdery mildew ( Blumeria graminis f． sp． tritici) ． The effects of fungicidal activityon leaves were detected through the progress of colonies． Riboflavin with different concentrations ( 0，10，15，25mol /L) was used respectively． The result showed that foliar application of riboflavin was helpful for wheat to restrictinginfection of powdery mildew． 3 d after pathogen inoculation，colonies were abruptly increased in control plants;7d after pathogen inoculation，colonies in plants with foliar application of riboflavin were also lower than control．However， the plants treated with foliar application of riboflavin showed absolutely defensive symptom． The initial response to foliar application of riboflavin in the leaves was hydrogen peroxide abruption，but there was no significantly difference among concentrations of riboflavin． While riboflavin was used together with CAT ( catalase) ，the function of riboflavin suppress the infection of powdery mildew in wheat disappeared; suggesting that the role of H₂O₂ regenerated by riboflavin in priming defenses is necessary．

Key words: Powdery mildew, Riboflavin, Defense, Hydrogen peroxide

CLC Number: 

• S435.121