title: Defoliation increases nutritional quality and allelochemics of pine seedlings.
abstract: The concentration of phenols, procyanidins, and protein in pine foliage was determined at two and eight weeks following mechanical defoliation of 0, 25, 50, and 75%. Changes in both mature and immature ponderosa pine, Pinus ponderosa Dougl. ex Laws, foliage were monitored. The lowest level of defoliation (25%) produced the largest increase in phenols; 75% defoliation caused the largest increase in procyanidins. The number of phenolic compounds in mature foliage doubled following 25% defoliation. Maximum protein production also occurred at moderate defaliation levels. Mechanical defoliation had a significant effect on the production of all compounds tested. The implications of these results for induced resistance research are discussed.
authors.affiliation: School of Forestry, Northerm Arizona University, Box 4098, 86011, Flagstaff, AZ, USA.
authors.forename: Michael R
authors.initials: MR
authors.lastname: Wagner
authors.affiliation: , Box 566, 97370, Philomath, OR, USA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Evans