Nitrogen and Carbon Metabolism

In order to investigate the intra-specific variation of wheat grain quality response to elevated atmospheric CO 2 concentration (e[CO 2 ]), eight wheat (Triticum aestivum L.)cultivars were grown at two CO 2 concentrations ([CO 2 ]) (current atmospheric, 389 CO 2 mmol mol À1 vs. e[CO 2 ], FACE (Free-Air CO 2 Enrichment), 550 AE 10% CO 2 mmol mol À1), at two water levels (rain-fed vs. irrigated) and at two times of sowing (TOS 1 , vs. TOS 2). The TOS treatment was mainly imposed to understand whether e[CO 2 ] could modify the effects of timing of higher grain filling temperatures on grain quality. When plants were grown at TOS 1 , TKW (thousand kernel weight), grain test weight, hardness index, P, Ca, Na and phytate were not significantly changed under e[CO 2 ]. On the other hand, e[CO 2 ] increased TKW (16%), hardness index (9%), kernel diameter (6%), test weight (2%) but decreased grain protein (10%) and grain phytate (11%) at TOS 2. In regard to grain Zn, Mn and Cu concentrations and some flour rheological properties, cultivar specific responses to e[CO 2 ] were observed at both sowing times. Observed genetic variability in response to e[CO 2 ] in terms of grain minerals and flour rheological properties could be easily incorporated into future wheat breeding programs to enable adaptation to climate change.

Dietary deficiencies of zinc and iron are a substantial global public health problem. An estimated two billion people suffer these deficiencies 1 , causing a loss of 63 million life-years annually 2,3 . Most of these people depend on C 3 grains and legumes as their primary dietary source of zinc and iron. Here we report that C 3 grains and legumes have lower concentrations of zinc and iron when grown under field conditions at the elevated atmospheric CO 2 concentration predicted for the middle of this century. C 3 crops other than legumes also have lower concentrations of protein, whereas C 4 crops seem to be less affected. Differences between cultivars of a single crop suggest that breeding for decreased sensitivity to atmospheric CO 2 concentration could partly address these new challenges to global health.

Dietary deficiencies of zinc and iron are a substantial global public health problem. An estimated two billion people suffer these deficiencies 1 , causing a loss of 63 million life-years annually 2,3 . Most of these people depend on C 3 grains and legumes as their primary dietary source of zinc and iron. Here we report that C 3 grains and legumes have lower concentrations of zinc and iron when grown under field conditions at the elevated atmospheric CO 2 concentration predicted for the middle of this century. C 3 crops other than legumes also have lower concentrations of protein, whereas C 4 crops seem to be less affected. Differences between cultivars of a single crop suggest that breeding for decreased sensitivity to atmospheric CO 2 concentration could partly address these new challenges to global health.

ABSTRACT Dietary deficiencies of zinc and iron are a substantial global public health problem. An estimated two billion people suffer these deficiencies, causing a loss of 63 million life-years annually. Most of these people depend on C3 grains and legumes as their primary dietary source of zinc and iron. Here we report that C3 grains and legumes have lower concentrations of zinc and iron when grown under field conditions at the elevated atmospheric CO2 concentration predicted for the middle of this century. C3 crops other than legumes also have lower concentrations of protein, whereas C4 crops seem to be less affected. Differences between cultivars of a single crop suggest that breeding for decreased sensitivity to atmospheric CO2 concentration could partly address these new challenges to global health.
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