INCREASING CELERY RESISTANCE TO PATHOGENS DURING STORAGE AND REDUCING HIGH-RISK PSORALEN CONCENTRATION BY TREATMENT WITH GA(3)

Since psoralens have a very weak antifungal activity in vitro, we propose that (+)marmesin, the precursor of psoralens in celery (Apium graveolens L.) is associated with celery resistance to pathogens. (+)Marmesin has at least 100 times greater antifungal activity in vitro than psoralens. After 1 month of storage at 2C, the concentration of total psoralens increased from 8 to 67 mu g . g(-1) fresh weight, (+)marmesin decreased from 27 to 4 mu g . g(-1) fresh weight, and the incidence of decay increased from 0% to 34%. However, when celery was treated with GA(3) before 1 month of storage at 2C, decay increased to only 7%, the concentration of psoralens increased to 31 mu g . g(-1) fresh weight, and the concentration of (+)marmesin decreased to 13 mu g . g(-1) fresh weight It seems that GA(3) retarded celery decay during storage by slowing down the conversion of (+)marmesin to psoralens, thereby increasing the resistance to pathogens during storage.