The substantial role of atmospheric CO 2 for photosynthesis had been admitted during the early nineteenth century.The rapid increase in atmospheric CO 2 concentration raises the interest again in photosynthetic response to CO 2 concentrations.Plant response to elevated CO 2 according to species,development stage and interaction of other factors,such as temperature,light,water and soil nutrient availability.Short term(minutes to days)exposure to elevated CO 2 often stimulates photosynthetic rate while ...