9311079 Mulkey The purpose of this Dissertation Improvement grant is to examine relative growth rates, root-shoot ratios, net assimilation, and relative species dominance as determinants of productivity and community composition under constraints of light, mycorrhizal infection, and hyphal transfer. A series of experiments will examine these factors at the individual, intraspecific, and interspecific levels in the laboratory and in the field. Field experiments using labeled phosphorus and carbon will be used to monitor transfer of nutrients from mycorrhizal fungi to plants and vice versa. Studies will be conducted at the Smithsonian Tropical Forest Research Institute to address the role of fungi in the restoration of degraded tropical forest ecosystems. %%% This study will obtain the first tropical data on the complex interactions of light, infection, and translocation, and will demonstrate the extent to which these affect individual plant production in a community, as well as local community dynamics. These data are critical for a better understanding of the belowground ecosystem and how it affects natural succession and reforestation in the tropics. ***
