Abstract: Chlorophyll is the most prominent pigment in plants that participates in the process of photosynthesis. It is an important factor in determining
the rate of photosynthesis. Based on the plastochron index, the chlorophyll concentration of the mature leaf was determined in selected plants
(Catharanthus roseus (L) G. Don (C3 plant), Andropogon citratus DC (C4 plant) and Bryophyllum bipinnatum (Lam) Oken (CAM plant). The plants were
grown in earthen pots (diameter 23 cm) under natural conditions in a net-home. The chlorophyll concentration in Catharanthus roseus (L) G. Don (C3
plants) was found to be more than in Andropogon citratus DC (C4 plant) and Bryophyllum bipinnatum (Lam) Oken (CAM plant). Based on the plastochron
index the growth rate of the C3 plant was faster than the C4 and CAM plants. This supports the fact that the C3 plants are more efficient in growth in
comparison to the C4 and CAM plants.