The continuous increase of the carbon dioxide (CO2) levels will reportedly affect various grains and legumes by significantly decreasing their zinc and iron contents, making them less nutritious.
University of Illinois and the Institute for Genomic Biology scientist Andrew Leakey joined his colleagues in a study that examined several varieties of sorghum, maize, soybeans, field peas, rice and wheat which are all grown in fields that have atmospheric carbon dioxide levels similar to the levels that are expected to occur in the middle of the current century. CO2 concentrations in the atmosphere are said to be approaching at the rate of 400 parts per million (ppm) which are predicted to reach as much as 550 ppm by 2050.
Their analysis revealed that as the amount of CO2 increases, the nutritional quality of a number of the most significant crops worldwide decreases. Zinc and iron went down significantly in soybeans and field peas. This decline is also seen in wheat and rice with an additional drop in their protein content.
The nutrients in maize and sorghum, meanwhile, remained relatively stable. These crops use the C4 photosynthesis - a process that concentrates the carbon dioxide in the leaves.
"C4 is sort of a fuel-injected photosynthesis that maize and sorghum and millet have. Our previous work here at Illinois has shown that their photosynthesis rates are not stimulated by being at elevated CO2. They already have high CO2 inside their leaves," said Leakey in the university news release.
Researchers used the Free Air CO2 Enrichment (FACE) to simulate the increasing CO2 levels. The system pumps out, monitors, and adjusts ground based CO2 to simulate future conditions. All the other growing conditions (sunlight, water, soil, temperature) remained the same for plants that are exposed to high CO2 and those that are used as controls.
Findings of this study were published in the May 7 issue of Nature.
