Peroxidase Allozyme Differentiation among Successional Stands of Ponderosa Pine

Abstract

Genetic variation of a peroxidase locus from mature ponderosa pine needles has been surveyed among four successional stands on the Shanahan Mesa near Boulder, Colorado. The recent colonization of this mesa by ponderosa pine can be documented by historical reports and tree cores. Allozyme differentiation was observed on the Shanahan Mesa between two recently colonized, open-grown stands and a shaded secondary growth stand, which parallels patterns of differentiation found in nearby mountain populations. At a transitional stand in the middle of the mesa, genetic differences also occurred between older open-grown trees and shaded younger trees. Environmental effects from canopy closure appear to have affected peroxidase differentiation among these successional stands.