Question

By looking at which internal structure of a plant, can you tell whether a plant is C3 or C4? Explain.

Answer 1

Hint: The C3 plants increase photosynthetic assimilation of carbon and decrease stomatal conductance. Those plants in which the first product of the carbon dioxide assimilation through photosynthesis is 3- Phosphoglycerate (3-PGA), it is a three-carbon compound, are called C3 plants. The plants that avoid photorespiration by using the enzyme phosphoenolpyruvate during the initial step of carbon fixation. It is said that the C4 plants are native to a hot and dry environment.

Complete answer:
> C4 plants possess a particular type of leaf anatomy known as Kranz anatomy. This cellular structure separates C4 plants from C3 plants.
> C4 plants consist of two types of cells, mesophyll cells, and bundle sheath cells. These cells are necessary for the C4 pathway.
> Bundle sheath cells are the large cells present around the vascular bundles of C4 plants. These cells are found only in C4 plants.
> Several layers around the vascular bundles are formed by bundle sheath cells. They are distinguished by having a large number of dimorphic chloroplasts, thick walls impervious to gaseous exchange, lacking grana, and no intercellular spaces.
> In C4 plants, photorespiration does not occur due to Kranz anatomy.

Additional information:
> C3 plants include the cereals barley oats, wheat, and rice, cotton, sunflower, alfalfa, Eucalyptus, sugar beets, soybeans, tobacco, potatoes, chlorella, and others.
> C4 plants include crops of millet, maize, sugar cane, and sorghum.
> Kranz anatomy is a structure where the mesophyll cells are clustered in a ring-like fashion around the bundle sheath cells.
> In C4 photosynthesis, a four-carbon compound is formed, that's why these are known as C4 plants.

Note: C3 plants are those plants in which the first product of the carbon dioxide assimilation through photosynthesis is 3- Phosphoglycerate (3-PGA), it is a three-carbon compound. In C4 photosynthesis, a four-carbon combination is formed, that's why these are known as C4 plants. C4 plants possess a particular type of leaf anatomy known as Kranz anatomy. This cellular structure separates C4 plants from C3 plants. C4 plants consist of two types of cells, mesophyll cells, and bundle sheath cells. These cells are necessary for the C4 pathway. In C4 plants, photorespiration does not occur due to Kranz anatomy.