Geoscience Reference
In-Depth Information
Fig. 11.2
A scheme of the chloroplast and of the thylakoids with pigments containing
chlorophyll
In majority of cultivated plants, because photosynthesis involves the conversion
of CO
2
into molecules with three carbons, we call this group C3 plants. In some
species called C4 plants, the CO
2
is fi rst converted into molecules containing four
carbons. If the concentration of CO
2
in the atmosphere is changed, C3 and C4 plants
are affected in a different way. In addition to these C3 and C4 plants having different
photosynthetic systems, a third group of plants with a completely unusual metabo-
lism of CO
2
also exists. They include 18 families and are called by the abbreviation
CAM (crassulacean acid metabolism). Unlike C3 and C4 plants that close their
