BIOCHEMICAL REACTIONS IN ROOTS OF MUSA-AC UMINATA (AAA CAVENDISH GROUP) CV POYO AND GROS-MICHEL INFESTED BY 3 NEMATODES

Three banana-parasitic nematodes, Radopholus similis, Helicotylenchus multicinctus and Hoplolaimus pararobustus, were inoculated on vitro-pl ants of Musa acuminata (AAA triploid) cv. Poyo and Gros Michel reared in containers. The evolution of concentration of total phenols and ind ols, and of peroxidase, polyphenoloxidase and lyase activities was rel ated to nematode densities in the roots. Histochemical measurements co nfirmed these observations. The same metabolic pathways occured in hea lthy plants of both cultivars but they were more intense in one than t he other. Compatibility of Poyo to R. similis was due to a high polyph enoloxidase activity. Gros Michel, which is less compatible to this ne matode, was characterized by a higher peroxidase activity. The polyphe nol pathway was more intense in Poyo than in Gros Michel. On the other hand, H. multicinctus and H. pararobustus did not change the phenol m etabolism significantly. It is concluded that compatibility of M. acum inata to phytoparasitic nematodes depends both on the cultivars and th e nematode species.