ABSTRACT
Artificially induced lightwood (oleoresin-saturated woody tissue) can be chemically induced through application of the bipyridilium herbicide paraquat (1,1 '-dimethyl-4,4'-bipyridilium dichloride; methyl viologen) to the xylem wood tissue of many species of pine (Pinus spp.). The increase in oleoresin content in the affected area may be as much as an order of magnitude, providing total yield increases of two to five times over control trees. Paraquat-induced lightwood formation seems to be the result of the repartitioning of the tree's fixed carbon resources into a directed synthesis of large quantities of oleoresin. Lightwood formation is the result of a complex set of physiological and biochemical events that are set into motion by the novel chemical properties of the bipyridilium molecule, paraquat.
