Nitrate supply and plant development influence nitrogen uptake and allocation under elevated CO<inf>2</inf> in durum wheat grown hydroponically
Growth in elevated CO<inf>2</inf> often leads to decreased plant nitrogen contents and down-regulation of photosynthetic capacity. Here, we investigated whether elevated CO<inf>2</inf> 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 CO<inf>2</inf> concentrations. Elevated CO<inf>2</inf> 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 CO<inf>2</inf> decreased the nitrogen content of roots with both levels of N and that of aboveground organs with high N. With low N, elevated CO<inf>2</inf> 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 CO<inf>2</inf> 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 CO<inf>2</inf>.
| Main Authors: | , , , , |
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| Other Authors: | |
| Format: | artículo biblioteca |
| Published: |
Springer
2015-05-27
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| Subjects: | Acclimation, Elevated CO2, Nitrate uptake, Nitrogen, Nitrogen allocation, Triticum durum, |
| Online Access: | http://hdl.handle.net/10261/271225 http://dx.doi.org/10.13039/501100000780 http://dx.doi.org/10.13039/501100003329 |
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| Summary: | Growth in elevated CO<inf>2</inf> often leads to decreased plant nitrogen contents and down-regulation of photosynthetic capacity. Here, we investigated whether elevated CO<inf>2</inf> 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 CO<inf>2</inf> concentrations. Elevated CO<inf>2</inf> 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 CO<inf>2</inf> decreased the nitrogen content of roots with both levels of N and that of aboveground organs with high N. With low N, elevated CO<inf>2</inf> 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 CO<inf>2</inf> 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 CO<inf>2</inf>. |
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