Definition: one of three metabolic pathways for carbon fixation in photosynthesis, along with C4 and CAM. This process converts carbon dioxide and ribulose bisphosphate (RuBP, a 5-carbon sugar) into 3-phosphoglycerate through the following reaction:
CO2 + H2O + RuBP → (2) 3-phosphoglycerate
This reaction occurs in all plants as the first step of the Calvin–Benson cycle.
Definition: The minimum tolerable temperature is the lowest temperature recorded in the plant’s historical range. If this is not available, the record low January temperature recorded at climate stations within the current geographical range of the plant is used. This definition does not apply to summer annuals.