The induced chemical defenses of norway spruce [Picea abies (L) Karst.] : ecological function and regulation
Methyl jasmonate, a well-known inducer of plant defense responses, was used to manipulate the biochemistry and anatomy of mature Picea abies (Norway spruce) stems. The aim of this study was to investigate if this treatment protected trees against attack by the blue-stain fungus Ceratocystis polonica [(Siem.) C. Moreau], the spruce bark beetle (Ips typographus L.) and the white pine weevil (Pissodes strobi Peck.). Application of methyl jasmonate lead to several biochemical and anatomical changes and the results suggest that induced defenses such as formation of traumatic resin ducts, enhancement of resin flow, and increased accumulation of volatile terpenes and diterpene resin acids, all triggered by application of jasmonates, play a significant role in Norway spruce defense against multiple enemies. The results also confirmed that the jasmonate pathway directly regulates the formation of these induced defenses.