Nitrogen fixation by Robinia pseudoacacia (L.) seedlings in the greenhouse under manipulated nitrogen and light treatments

Symbiotic nitrogen fixation (SNF) is a critical mechanism of ecosystem recovery, and in forests of the eastern United States, the most common tree species that supports SNF is black locust (Robinia pseudoacacia L.). Despite its prevalence, black locust’s fixation strategy—whether it maintains fixation at a constant rate (obligate fixation) or reduces its fixation rate (facultative fixation)—is unknown. In this study we examined how nitrogen (N) and light control SNF by black locust, by growing seedlings under two nitrogen levels (nitrogen added and nitrogen not added) and across four levels of light (10%, 20%, 40%, and 100%), with 12-13 replicates for each nitrogen x light treatment. This experiment, conducted at the Coweeta Hydrologic Laboratory in North Carolina, started in May 2020 and seedlings were harvested at the end of 12 weeks. This data publication includes the biomass measurements, net photosynthesis, and nodule activity for each replicate from each of 8 light transmittance and nitrogen treatments.
We aimed to examine how light levels and nitrogen addition affected nodulation and nitrogen fixation by Robinia pseudoacacia seedlings.
For more information about this study and these data, see Ottinger et al. (2023).