Effects of Elevated CO₂ on the Capacity for Photosynthesis of a Single Leaf and a Whole Plant, and on Growth in a Radish

摘要

The atmospheric concentration of CO₂ will probably rise to about 700 µmol mol–1 by the end of this century. The effects of elevated growth CO₂ on photosynthesis are still not fully understood. Effects of elevated growth CO₂ on the capacity for photosynthesis of a single leaf and a whole plant were investigated with the radish cultivar White Cherish. The plants were grown under ambient (∼400 µmol mol–1) or elevated CO₂ (∼750 µmol mol–1). The rates of net photosynthesis per leaf area with a whole plant and a single leaf of plants of various ages (15–26 d after planting) were measured under ambient and elevated CO₂. The rates of photosynthesis were increased by 20–28% by elevated CO₂. There was no effect of elevated growth CO₂ on the rate of photosynthesis, clearly indicating no downward acclimation of photosynthesis to elevated CO₂. Elevated CO₂ increased dry weight accumulation by >27%. The effect of elevated CO₂ on other growth characteristics will also be shown.