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.