Higher CO2 Levels Increase Wheat Production but Lower Nutritional Quality

Scientists anticipate that increasing carbon dioxide (CO₂) levels in the air could lead to hotter temperatures and more droughts.

These climatic changes can negatively affect the growth of several plants. However, the increased supply of CO₂ could, in fact, be useful since plants can use the greenhouse gas to prepare food through photosynthesis.

Currently, scientists have reported in Journal of Agricultural and Food Chemistry, an ACS journal, that an increased level of CO₂ could maximize wheat production but slightly decrease its nutritional quality.

One of the most important crops in the world is wheat. Wheat flour is used as a chief ingredient in many foods like pasta, bread, and pastries. Scientists have previously shown that large amounts of CO₂ could increase the production of wheat at the cost of its standard characteristics like protein and nitrogen content.

They are, however, not sure of the complete chain of wheat quality changes that occur at various stages of development or the underlying biochemical mechanisms. Iker Aranjuelo and coworkers desired to investigate how increased CO₂ can affect yield, metabolism, and quality of wheat during its development and at maturity.

The research team grew wheat in greenhouses at normal (400 ppm) and increased (700 ppm) CO₂ concentrations. They discovered that wheat grown under increased CO₂ levels exhibited a 104% higher yield of full-grown wheat, but its nitrogen content was 0.5% lower, including a small reduction in free amino acids and protein content.

They examined the metabolic changes in the wheat at various developmental stages using gas chromatography-mass spectrometry. In addition to other changes, increased CO₂ modified the levels of specific nitrogen-containing amino acids during production and at maturity.

According to the scientists, despite the fact that the observed metabolic changes had moderate effects on the quality of fully grown wheat, the effects could be intensified by other changes in the environment of plants, for example, drought conditions or limited nitrogen availability.

The study was financially supported by the Spanish Ministry of Science, Innovation and Universities.