ACCUMULATION OF PHYTOALEXINS IN LEAVES OF PLANE TREE (PLATANUS SPP) EXPRESSING SUSCEPTIBILITY OR RESISTANCE TO CERATOCYSTIS-FIMBRIATA F-SP PLATANI

Inoculation of leaves of resistant Platanus occidentalis and susceptib le Platanus acerifolia leaves with Ceratocystis fimbriata f. sp. plata ni, the canker stain disease agent, induced foliar necrosis and biosyn thesis of two phytoalexins, scopoletin and umbelliferone. Foliar sympt oms keep localized and accumulation of coumarin phytoalexins was rapid for incompatible interactions. Necrosis spread widely and accumulatio n of these phenolic: compounds was much later and lower for compatible interactions. The differential response could be used in a genetic im provement program for resistance against canker stain.