Fractionation of carbon isotopes in oxygenic photosynthesis the bundle sheath cells. This limits the carbon available to RuBisCO, which in turn lowers its fractionation effect. This accounts for the overall delta value in C4 plants to be -12 to -16 ‰. Plants that use Crassulacean acid metabolism, also known as CAM photosynthesis, temporally separate their chemical reactions between day and night. This strategy modulates stomatal conductance to increase water-use efficiency, so is well-adapted for arid climates. During the night, CAM plants open stomata to allow CO to enter the cell and undergo fixation into organic acids that are stored in vacuoles. This carbon is released to the
Photosynthesis cytosol they turn back into CO very slowly without the help of carbonic anhydrase. This causes the HCO ions to accumulate within the cell from where they diffuse into the carboxysomes. Pyrenoids in algae and hornworts also act to concentrate around rubisco. The overall process of photosynthesis takes place in four stages: Plants usually convert light into chemical energy with a photosynthetic efficiency of 3–6%. Absorbed light that is unconverted is dissipated primarily as heat, with a small fraction (1–2%) re-emitted as chlorophyll fluorescence at longer (redder) wavelengths. This fact allows measurement of the light reaction of photosynthesis by using