Article,
Wheat grain quality under increasing atmospheric CO2 concentrations in a semi-arid cropping system
Journal of Cereal Science, 56 (3): 684--690 (November 2012)
DOI: 10.1016/j.jcs.2012.07.010
Abstract
We investigated wheat (Triticum aestivum) grain quality under Free Air CO2 Enrichment (FACE) of 550±10\% CO2 μmol mol−1. In each of two full growing seasons (2008 and 2009), two times of sowing were compared, with late sowing designed to mimic high temperature during grain filling. Grain samples were subjected to a range of physical, nutritional and rheological quality assessments. Elevated CO2 increased thousand grain weight (8\%) and grain diameter (5\%). Flour protein concentration was reduced by 11\% at eCO2, with the highest reduction being observed at the late time of sowing in 2009, (15\%). Most of the grain mineral concentrations decreased under eCO2 - Ca (11\%), Mg (7\%), P (11\%) and S (7\%), Fe (10\%), Zn (17\%), Na (19\%), while total uptake of these nutrients per unit ground area increased. Rheological properties of the flour were altered by eCO2 and bread volume reduced by 7\%. Phytate concentration in grains tended to decrease (17\%) at eCO2 while grain fructan concentration remained unchanged. The data suggest that rising atmospheric CO2 will reduce the nutritional and rheological quality of wheat grain, but at high temperature, eCO2 effects may be moderated. Reduced phytate concentrations at eCO2 may improve bioavailability of Fe and Zn in wheat grain. ⺠Wheat (cv. Yitpi) grown at elevated CO2 at 2 sown times; late sown provided higher stress to crops. ⺠Grain nutrient, anti-nutrient and flour rheological properties were analysed. ⺠Flour protein, some minerals, phytate concentrations were reduced at elevated CO2. ⺠Flour rheological properties were negatively changed at elevated CO2. ⺠Net effect of fructans, phytate may improve bioavailability of Fe, Zn in wheat flour.
