Differentiated mineral nutrient management in two bamboo species under elevated CO2 environment.

Mineral nutrients play a critical role in maintaining plant growth, but are vulnerable to climate change, such as elevated atmospheric carbon dioxide (CO2) concentrations. Previous studies reported that impact of elevated CO2 concentrations on plant growth vary among plant species, which may affect differential mineral nutrient cycling among plant species. However, little is known about how increasing CO2 concentrations affect mineral nutrient uptake and allocation in bamboo species. Using open top chambers (OTCs), we investigated the effects of elevated CO2 concentrations on three key mineral nutrients (iron (Fe), calcium (Ca), and magnesium (Mg)) in two mature bamboo species (Phyllostachys edulis and Oligostachyum lubricum). Results showed increased leaf and root biomass under elevated CO2 concentrations (P. edulis: 30.24% and 10.94%; O. lubricum: 24.47% and 13.84%, respectively). Conversely, elevated CO2 concentrations had negligible effects on the biomass of other bamboo organs (e.g., branches and culms). To a certain extent, elevated CO2 concentrations also caused nutrient variation among the various organs of these two species. For Ph. edulis, elevated CO2 concentrations increased mineral content (Fe, Ca, and Mg) in and allocation to leaves while it decreased Fe and Mg allocation to roots. By contrast, elevated CO2 concentrations only increased mineral content in and allocation to O. lubricum leaves and decreased Mg to its roots. Results confirmed that elevated CO2 concentrations resulted in differential mineral nutrient uptake and allocation response between these two species. Understanding such differences is critical to the sustainable nutrient management of bamboo ecosystems under increasing CO2 concentrations.