About Lesson
Hatch and slack cycle or c4 – cycle
- Initially, it was believed that CO2 fixation takes place only by the Calvin cycle.
- But in 1954, in addition to the Calvin cycle, an alternate pathway to CO2 fixation in photosynthesis was discovered by Kortschak et al. who reported the formation of C4 dicarboxylic acid as the primary product of photosynthesis in sugarcane.
- D Hatch and C.R.Slack (1966) proposed an alternative pathway of CO2 fixation which is now known as the Hatch and Slack pathway or C4-dicarboxylic acid pathway or C4-cycle or ß-carboxylation cycle.
- This cycle is known as the C4 cycle because the first stable product of this cycle is a four-carbon
- compound known as oxaloacetic acid (OAA)
