Effects of atmospheric CO(2) enrichment on plant constituents related to animal and human health.

Atmospheric CO(2) enrichment is known to significantly enhance the growth and development of nearly all plants, implying a potential for elevated levels of CO(2) to alter the concentrations of plant constituents related to animal and human health. Our review of this subject indicates that increases in the air's CO(2) content typically lead to reductions in the nitrogen and protein concentrations of animal-sustaining forage and human-sustaining cereal grains when soil nitrogen levels are sub-optimal. When plants are supplied with all the nitrogen they can use, however, no such reductions are observed. CO(2)-enriched plants growing in the natural environment also tend to overcome initial reductions in plant mineral concentrations as time progresses, possibly due to development of larger root systems and consequent enhanced abilities to locate and absorb mineral nutrients. Atmospheric CO(2) enrichment additionally appears to reduce oxidative stresses in plants; and it has been shown to increase the concentration of vitamin C in certain fruits and vegetables. Elevated CO(2) has also been demonstrated to increase the biomass of plants grown for medicinal purposes while simultaneously increasing the concentrations of the disease-fighting substances produced within them. It is likely, therefore, that the ongoing rise in the air's CO(2) content will continue to increase food production around the world, while maintaining the nutritive quality of that food and enhancing the production of certain disease-inhibiting plant compounds.