If carbon dioxide is completely removed from a plant's environment, I would expect the plant's production of high-energy sugars to decrease. The amount of sugar produced by a plant is, within a limit, proportional to the amount of carbon dioxide available. You can see this by looking at the chemical formula for photosynthesis: 6CO2 + 6H2O + light energy = C6H12O6 + 6O2. As one can see, it takes exactly 6 carbon dioxide atoms (among other things) to produce 1 molecule of sugar. If you were to remove remove the carbon dioxide from the plant's environment, it'd have no carbon dioxide to produce the sugar.