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Nitrate supply and plant development influence nitrogen uptake and allocation under elevated CO2 in durum wheat grown hydroponically

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Abstract

Growth in elevated CO2 often leads to decreased plant nitrogen contents and down-regulation of photosynthetic capacity. Here, we investigated whether elevated CO2 limits nitrogen uptake when nutrient movement to roots is unrestricted, and the dependence of this limitation on nitrogen supply and plant development in durum wheat (Triticum durum Desf.). Plants were grown hydroponically at two N supplies and ambient and elevated CO2 concentrations. Elevated CO2 decreased nitrate uptake per unit root mass with low N supply at early grain filling, but not at anthesis. This decrease was not associated with higher nitrate or amino acid, or lower non-structural carbohydrate contents in roots. At anthesis, elevated CO2 decreased the nitrogen content of roots with both levels of N and that of aboveground organs with high N. With low N, elevated CO2 increased N allocation to aboveground plant organs and nitrogen concentration per unit flag leaf area at anthesis, and per unit aboveground dry mass at both growth stages. The results from the hydroponic experiment suggest that elevated CO2 restricts nitrate uptake late in development, high N supply overriding this restriction. Increased nitrogen allocation to young leaves at low N supply could alleviate photosynthetic acclimation to elevated CO2.

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Acknowledgments

This work has been funded by the Spanish National Research and Development Programme-European Regional Development Fund, ERDF (grant no. AGL2009-11987). R.V. was the recipient of a fellowship with reference BES-2010-031029. We are grateful to Dr J.M. Igual for his critical review of the manuscript. The technical cooperation of A. Verdejo and M.A. Boyero in control of hydroponic cultures, harvesting and N measurements is acknowledged.

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All authors have no conflicts of interest.

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  1. Institute of Natural Resources and Agrobiology of Salamanca, CSIC, Cordel de Merinas 40-52, 37008, Salamanca, Spain

    Rubén Vicente, Pilar Pérez, Rafael Martínez-Carrasco, Elena Gutiérrez & Rosa Morcuende

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  1. Rubén Vicente
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  2. Pilar Pérez
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  3. Rafael Martínez-Carrasco
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Correspondence to Rosa Morcuende.

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Communicated by W. Filek.

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11738_2015_1867_MOESM1_ESM.tif

Supplementary Fig. 1 Mean daily courses of temperature, relative humidity and CO2 concentration in controlled environment chambers used for ambient (white circles) or elevated (black circles) [CO2] treatments. Records correspond to hourly averages ± standard deviation for the duration of the whole experiment(TIFF 440 kb)

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Vicente, R., Pérez, P., Martínez-Carrasco, R. et al. Nitrate supply and plant development influence nitrogen uptake and allocation under elevated CO2 in durum wheat grown hydroponically. Acta Physiol Plant 37, 114 (2015). https://doi.org/10.1007/s11738-015-1867-y

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