Responses of rice qualitative characteristics to elevated carbon dioxide and higher temperature: implications for global nutrition

Abstract BACKGROUND Protein and some minerals of rice seed are negatively affected by projected carbon dioxide (CO 2 ) levels. However, an in‐depth assessment of rice quality that encompasses both CO 2 and temperature for a wide range of nutritional parameters is not available. Using a free‐air CO 2 enrichment facility with temperature control, we conducted a field experiment with two levels of CO 2 (ambient; ambient + 200 ppm) and two levels of temperature (ambient; ambient + 1.5 °C). An in‐depth examination of qualitative factors indicated a variable nutritional response. RESULTS For total protein, albumin, glutelin, and prolamin, elevated CO 2 reduced seed concentrations irrespective of temperature. Similarly, several amino acids declined further as a function of higher temperature and elevated CO 2 relative to elevated CO 2 alone. Higher temperature increased the lipid percentage of seed; however, elevated CO 2 reduced the overall lipid content. At the nutrient elements level, whereas elevated CO 2 reduced certain elements, a combination of CO 2 and temperature could compensate for CO 2 reductions but was element dependent. CONCLUSION Overall, these data are, at present, the most detailed analysis of rising CO 2 /temperature on the qualitative characteristics of rice. They indicate that climate change is likely to significantly impact the nutritional integrity of rice, with subsequent changes in human health on a global basis. © 2020 Society of Chemical Industry