Afek, U., Department of Postharvest Science and Fresh Produce, ARO, The Volcani Center, Bet Dagan, 50250, Israel
Carmeli, S., School of Chemistry, Tel Aviv University, Ramat Aviv, Tel Aviv, 69978, Israel
Aharoni, N., Department of Postharvest Science and Fresh Produce, ARO, The Volcani Center, Bet Dagan, 50250, Israel

Columbianetin, rather than psoralens, was found to be a new phytoalexin associated with celery (Apium graveolens) resistance to pathogens during storage. In vitro, columbianetin had at least 80 times greater antifungal activity than furanocoumarins (psoralens and angelicin). In vivo, the concentration of furanocoumarins in celery was 8μg g-1 fr. wt, and this is less than 0.25% of the concentration required for growth inhibition of celery pathogens. However, the concentration of columbianetin in vivo was 38μg g-1 fr. wt, and this is close to the concentration required for growth inhibition of celery pathogens in vitro. © 1995.