Dark Reaction

a stage in PHOTOSYNTHESIS which is not directly dependent on light. It takes place within the CHLOROPLASTS of the cells of green plants.

Taken from Dictionary of Science

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Photosynthesis, or the light-independent reactions, are chemical reactions that convert carbon dioxide and other compounds into glucose. The reactions occur in the stroma, the fluid-filled area of a chloroplast outside of the thylakoid membranes. These reactions take the products of the light-dependent reactions and perform further chemical processes on them. There are three phases to the light-independent reactions, collectively called the Calvin Cycle: carbon fixation, reduction reactions, and ribulose 1,5-diphosphate (RuDP) regeneration.

The light-independent reactions are sometimes referred to as the dark reactions, though that term may be misleading as they do not actually require darkness to proceed. The term "light-independent" is used to emphasize that the reactions continue even in the absence of light as long as the proper substrate compounds are available. However, because the availability of substrates in plants depends on photosynthesis, the reactions cannot be said to be entirely "light-independent." The term "dark reactions" may be more accurate in CAM (Crassulacean acid metabolism) plants, which only take up CO₂, which is necessary for the reactions to proceed, at night.

Taken from Wikipedia