Infection of roots of Norway spruce (Picea abies) by Heterobasidion annosum

Abstract Wounding of excised roots of Norway spruce [Picea abies (L.) Karst.] caused a rapid accumulation of phenolic compounds, decrease of starch content and of certain enzyme activities in the ray cells. Infection of the wounds by Heterobasidion annosum (Fr.) Bref. intensified these processes, caused oxidation of the phenols, and induced activity of acid phosphatase and β‐glucosidase in the ray cells of the infected area. The reactions were oxygen‐dependent. Intra‐ and extracellular enzymes were detected in the wood‐infecting hyphae. Other wood‐growing fungi caused similar reactions in the wood as H. annosum.