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Effect of drought and carbon dioxide on nutrient uptake and levels of nutrient‐uptake proteins in roots of barley
Author(s) -
Bista Deepesh R.,
Heckathorn Scott A.,
Jayawardena Dileepa M.,
Boldt Jennifer K.
Publication year - 2020
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/ajb2.1542
Subject(s) - nutrient , carbon dioxide , hordeum vulgare , biology , phosphorus , agronomy , zoology , shoot , horticulture , chemistry , poaceae , ecology , organic chemistry
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.