Effects of atmospheric CO2 enrichment on plant constituents related to animal and human health

Atmospheric CO2 enrichment is known to significantly enhance the growth and development of nearly all plants, implying a potential for elevated levels of CO2 to alter the concentrations of plant constituents related to animal and human health. Our review of this subject indicates that increases in t he air's CO2 content typically lead to reductions in the nitrogen and prote in concentrations of animal-sustaining forage and human-sustaining cereal g rains when soil nitrogen levels are sub-optimal. When plants are supplied w ith all the nitrogen they can use, however. no such reductions are observed . CO2-enriched plants growing in the natural environment also tend to overc ome 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 CO2 enrichmen t additionally appears to reduce oxidative stresses in plants: and it has b een shown to increase the concentration of vitamin C in certain fruits and vegetables. Elevated CO2 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 CO2 content will continue to increase food production around the world. while maintaining th e nutritive quality of that food and enhancing the production of certain di sease-inhibiting plant compounds. (C) 2001 Elsevier Science B.V. All rights reserved.