Root traits that influence nutrient foraging in different plants are poorly understood. In most plants, roots form a symbiotic association with mycorrhizal fungi that may improve the ability of the plant to forage for nutrients. However, species differ in the extent that mycorrhizae can benefit nutrient uptake, and this is likely related to root morphology, including root diameter and root hair abundance. The PIs hypothesize that tree species with coarse roots with few or short root hairs forage in nutrient-rich patches by relying heavily on mycorrhizal fungi, while tree species with more rapidly growing roots that produce many long root hairs forage for nutrients by proliferating their roots, increasing root hair development and altering the rate of nutrient uptake. The project will be primarily conducted in a 14-year-old planting of 16 different tree species that vary widely in root morphology, although additional studies will be conducted in natural forest stands and in growth chambers. This study will improve the theoretical basis by which plant roots can be used for calculating the influence of vegetation on elemental cycles, improve predictions of vegetation responses and feedbacks to climate change, and increase the understanding of roots needed for better management of crops and trees for food and fiber. There will be a strong educational component to this research, including the training of three graduate students, undergraduate training in research and international exchanges of students and scientists.
