THE INVOLVEMENT OF MARMESIN IN CELERY RESISTANCE TO PATHOGENS DURING STORAGE AND THE EFFECT OF TEMPERATURE ON ITS CONCENTRATION

We show evidences that (+)marmesin, rather than linear furanocoumarins (psoralens), may play the major role in celery resistance to pathogens during storage. (+)Marmesin, the precursor of psoralens in celery, has at least 100 times greater antifungal activity in vitro in the dark than psoralens. Increased susceptibility of celery to pathogens during 1 mo of storage was accompanied by a decrease in (+)marmesin concentration and a corresponding increase in psoralen concentration. An increase in celery decay was negatively correlated with (+)marmesin concentration and positively correlated with psoralen concentration. After 1 mo of storage at 0 or 2 C, the concentration of psoralens increased from 10 to 136 or 78 mu g g(-1) fr. wt., respectively, while the concentration of (+)marmesin under the same storage conditions decreased from 33 to 4 or 11 mu g g(-1) fr. wt., respectively. Incidence of decay after 1 mo of storage at 0 or 2 C was 62 or 27%, respectively.