A. Compare C4 and C3 plants with regard to how they manage transpiration rate during the day. b. How do CAM plants manage transpiration?
C4 plants are typically found in dry and warm ecosystems. The water manage mechanism involves a spacial separation of carbon fixation.
The leaves of C4 plants have a special anatomy called Kranz anatomy.
The cells of vascular sheet also have chloroplasts as in the mesophyl.
In mesophyl cells occurs the first step of fixation whereas a enzyme called pep carboxylase fixate carbon dioxide forming malic acid or oxaloacetate.
These cetoacids are transported to the vascular sheet cells where the carbon dioxide is transferred to RUBP (pentose) forming 3 -phosphoglycerate. The enzyme envolved its called Rubisco.
The C4 metabolism intend to shunt the oxidation role of Rubisco that reduces efficiency. That is obtained by isolation of the enzyme in high pressure carbon dioxide atmosphere.
The CAM plants maintain its stomata closed all day long. The carbon dioxide is storage in the form of malate during the night using the same enzyme founded in C4 plants (pep carboxylase).
During day time the carbon dioxide is released and fixated by Rubisco. We can say that the carbon fixation has time separation.
Now let’s compare C4 and CAM plants