It takes 114 Kcal to reduce one mole of CO 2 to hexose, so the theoretical efficiency is 114/381 or 30%. Remarkably, Moore, et al. report that 25% has been achieved under laboratory conditions. The top efficiency they reported under natural growing conditions was the winter-evening primrose growing in Death Valley at 8% (if you can call Death Valley natural conditions!). Sugarcane has registered 7% , which is very important for a food crop. Sugarcane is a C4 plant , and under high sunlight conditions they will usually outperform C3 plants and others.
Photosynthesis is the process where plants make their own food from sunlight. Most plants are able to make food directly from light energy, for example the Sun, instead of eating other organisms or relying on nutrients. Photosynthesis can happen in plants because they have chlorophyll. Chlorophyll is the pigment that makes plants green. Chlorophyll captures the Sun’s energy and uses it to make sugars out of carbon dioxide from the air and water. The sugars fuel a plant's roots, stems, and leaves so the plant can grow. After plants use the Sun's light to make their food, plants release oxygen into the air. This oxygen is very helpful because humans and animals need it to breathe. Make sure you thank plants for the oxygen you use everyday!