Increased temperatures may safeguard the nutritional quality of crops under future elevated CO₂ concentrations

Abstract

SummaryIron (Fe) and zinc (Zn) deficiencies are a global human health problem that may worsen by the growth of crops at elevated atmospheric CO 2 concentration (eCO 2). However, climate change will also involve higher temperature, but it is unclear how the combined effect of eCO 2 and higher temperature will affect the nutritional quality of food crops. To begin to address this question, we grew soybean (Glycine max) in a Temperature by Free‐Air CO 2 Enrichment (T‐FACE) experiment in 2014 and 2015 under ambient (400 μmol mol−1) and elevated (600 μmol mol−1) CO 2 concentrations, and under ambient and elevated temperatures (+2.7°C day and +3.4°C at night). In our study, eCO 2 significantly decreased Fe concentration in soybean seeds in both seasons (−8.7 and −7.7%) and Zn concentration in one season (−8.9%), while higher temperature (at ambient CO 2 concentration) had the opposite effect. The combination of eCO 2 with elevated temperature generally restored seed Fe and Zn concentrations to levels obtained under ambient CO 2 and temperature conditions, suggesting that the potential threat to human nutrition by increasing CO 2 concentration may not be realized. In general, seed Fe concentration was negatively correlated with yield, suggesting inherent limitations to increasing seed Fe. In addition, we confirm our previous report that the concentration of seed storage products and several minerals varies with node position at which the seeds developed. Overall, these results demonstrate the complexity of predicting climate change effects on food and nutritional security when various environmental parameters change in an interactive manner.

Preserving the nutritional quality of crop plants under a changing climate: importance and strategies

“…However, increasing temperature to 35°C or higher, exceeded the beneficial effects of eCO 2 (Madan et al 2012). The combination of eCO2 with eT has a variable effect on growth and photosynthesis, and is dependent on the range of temperature increase, but in general eCO 2 reduced the negative impact of eT (Köhler et al 2018;Qiao et al 2019;Yu et al 2012). This was confirmed in soybean and maize over five-year growing seasons in open top chambers (Qiao et al 2019).…”

“…Sublett et al (2018) studied the consequence of eT (+8°C) on lettuce in a greenhouse experiment, and found a decrease in leaf Mg, K, Ca Mn and Mo concentrations. When looking at temperature and eCO 2 , it was shown that the combination of both factors may restore soybean (Köhler et al 2018) and wheat (Asif et al 2019) seed Fe and Zn concentrations to levels obtained under ambient CO 2 (aCO 2 ). However, since there is a strong species and cultivar dependency on these responses, care must be taken to look at these aspects in detail.…”

30 years of free‐air carbon dioxide enrichment (FACE): What have we learned about future crop productivity and its potential for adaptation?

“…enables nesting of open-air drought, temperature, and ozone treatments, as well as the free movement of pests and pathogens, and testing of a range of crop genotypes (e.g., Bourgault et al, 2016Bourgault et al, , 2017Gray et al, 2016;Hasegawa et al, 2013;He et al, 2014;Köhler et al, 2019;Ruiz-Vera et al, 2013).…”

“…Zhu et al (2018) suggested that many more genotypes would need to be screened in order to identify sufficient genetic variation for selection. To add to this challenge, the presence of other stresses associated with climate change alter grain quality responses to elevated [CO 2 ] (Köhler et al, 2019). Again, this speaks to the need for FACE facilities of adequate scale for breeder selection (Ainsworth et al, 2008).…”

The influence of rising tropospheric carbon dioxide and ozone on plant productivity

“…While many studies have shown a reduction in mineral nutrition in crops grown at elevated [CO 2 ], recent studies that investigated the combination of rising [CO 2 ] and warming reported that elevated temperatures can restore mineral concentrations to ambient conditions in soybean (Köhler et al . ; Palacios et al . ).…”