2020/10/01 by Deepesh R. Bista, Scott A. Heckathorn, Dileepa M. Jayawardena +1 · 5 citations
Agricultural and Biological Sciences · Earth and Planetary Sciences · #Plant responses to elevated CO2 #Atmospheric chemistry and aerosols #Soil Carbon and Nitrogen Dynamics
paper · pdf · doi:10.1002/ajb2.1542
Premise Atmospheric carbon dioxide (CO 2 ) concentration is increasing, as is the frequency and duration of drought in some regions. Elevated CO 2 can decrease the effects of drought by further decreasing stomatal opening and, hence, water loss from leaves. Both elevated CO 2 and drought typically decrease plant nutrient concentration, but their interactive effects on nutrient status and uptake are little studied. We investigated whether elevated CO 2 helps negate the decrease in plant nutrient status during drought by upregulating nutrient‐uptake proteins in roots. Methods Barley ( Hordeum vulgare ) was subjected to current vs. elevated CO 2 (400 or 700 ppm) and drought vs. well‐watered conditions, after which we measured biomass, tissue nitrogen (N) and phosphorus (P) concentrations (%N and P), N‐ and P‐uptake rates, and the concentration of the major N‐ and P‐uptake proteins in roots. Results Elevated CO 2 decreased the impact of drought on biomass. In contrast, both drought and elevated CO 2 decreased %N and %P in most cases, and their effects were additive for shoots. Root N‐ and P‐uptake rates were strongly decreased by drought, but were not significantly affected by CO 2 . Averaged across treatments, both drought and high CO 2 resulted in upregulation of NRT1 (NO 3 − transporter) and AMT1 (NH 4 + transporter) per unit total root protein, while only drought increased PHT1 (P transporter). Conclusions Elevated CO 2 exacerbated decreases in %N and %P, and hence food quality, during drought, despite increases in the concentration of nutrient‐uptake proteins in roots, indicating other limitations to nutrient uptake.