Grain mineral contents under elevated carbon dioxide

The impact of elevated [CO₂] at two different sowing times over 2 years on wheat (cv. Yitpi) grain physical, chemical, rheological quality traits under Free Air CO₂ Enrichment (FACE) was investigated. Most of the grain physical qualities improved under elevated [CO₂], but protein concentration was reduced by 12%. Similarly, most of the grain macro- and micronutrient concentrations were reduced at elevated [CO₂], while total mineral uptakes of N, P, K, Ca, Mg, S, Zn, and Fe were increased. The concentration of grain phytate was reduced at elevated [CO₂], but grain fructan concentration was unchanged. The rheological characteristics of the flour were changed at elevated [CO₂]. The magnitudes of reduction in grain physical, chemical, and rheological quality parameters were greatest at elevated [CO₂] in 2009-TOS₂, which experienced heat stress.

These data suggest that most of the beneficial effects of elevated [CO₂] on grain physical quality are counteracted by its negative impact on grain chemical and rheological quality traits suggesting a negative impact on human health and economy of wheat product-based industries. However, net effect of unchanged fructans and decreasing phytate concentrations should be improved bioavailability of Fe and Zn, which could help to partially offset the negative effects of elevated [CO₂]. Increased nutrient uptake suggests that nutrient management strategies are needed to develop sustainable food production under future climate.

This research was undertaken by Nimesha Fernando, PhD student with The University of Melbourne and has been accepted for publication in the journal Food Chemistry. ANZ-05