MYCORRHIZAE DIFFERENTIALLY ALTER GROWTH, PHYSIOLOGY, AND COMPETITIVE ABILITY OF AN INVASIVE SHRUB

Mycorrhizae improve phosphorus availability to host plants and alter their morphology, physiology, and competitive ability. We examined how different isolates of arbuscular mycorrhizal fungi, soil-P, light, and competition affect the growth, physiology, and biomass allocation of seedlings of an exotic invasive shrub of the southeastern United States, Ardisia crenata, in two greenhouse experiments. When Ardisia seedlings were grown singly in pots without competition, soil phosphorus concentration and light had no effect on seedling growth. Relative growth rates (RGR) and leaf area ratio (LAR), however, were higher for seedlings inoculated with mycorrhizal fungi isolated from Ardisia roots than those inoculated with single-spore isolates and nonmycorrhizal controls. In the second experiment, an Ardisia seedling was grown in each pot in competition with another conspecific seedling or with a seedling of Prunus caroliniana, a native subcanopy tree. The identity of the competitor had little effect on seedling ...