This award will support collaborative research in ecology between Dr. David Myrold, Oregon State University and Dr. Kerstin Huss-Danell, Department of Plant Physiology, University of Umea, Sweden. The project will examine two important questions concerning Alnus-Frankia symbiosis, namely the effect of several factors on the biomass and diversity of Frankia in the soil and the amount of fixed N released to the soil by nodulated Alnus. In particular, soil will be sampled from an established research site that has been treated by liming, NPK fertilization and the introduction of alder. This soil will be assayed for Frankia biomass by plant bioassay and DNA probe methods. The results of these experiments will not only provide important new information in understanding Alnus-Frankia symbiosis, but will by extension provide new insight into actinorhizal plants in general. These plants are ecologically important, because they can alter ecosystem level processes by rapidly altering the nitrogen content of the systems in which they occur. They also have importance in forestry, land reclamation and horticulture. This project will benefit from the compleme- ntary expertise of Dr. Myrold in microbiology and of Dr. Huss-Danell in plant physiology. Dr. Myrold will also be able to take advantage of a field site in Sweden which has been extensively studied and is exceptionally well suited to the proposed research.
