Wood Tannins - Isolation and Significance in Host Resistance to Verticillium Wilt Disease

Abstract

Apricot trees often recover from the "black heart" disease incited by the fungus Verticillium albo-atrum Reinke & Berthold, and a characteristic of such resistant trees is that the infected wood becomes dark brown to black in colour (Dufrenoy and Dufrenoy 1927). The fungus dies 1-6 months after it has colonized the wood (Taylor 1963). Analysis of total phenolics by the Folin-Denis assay showed an approximate fivefold increase (to about 60 mgjg wood) compared with that of uninfected wood of the same branch, and suggested their involvement in disease resistance mechanisms.