Question

Plants showing C${}_4$ photosynthesis have

• A. Granal bundle sheath chloroplasts and agranal mesophyll chloroplasts
• B. Agranal bundle sheath chloroplasts and granal mesophyll chloroplasts
• C. Both bundle sheath and mesophyll chloroplasts are agranal
• D. Both the types of chloroplasts are granal

Answer 1

Answer: (B)

Agranal bundle sheath chloroplasts and granal mesophyll chloroplasts

C${}_4$ plants have Kranz anatomy of a leaf. The vascular bundles in these leaves are surrounded by a layer of bundle sheath cells that contain a large number of chloroplasts.

The chloroplasts in these leaves are dimorphic:

Bundle sheath- Chloroplast larger in size and arranged centripetally. It has unstacked thylakoids called agranal chloroplast. The cells perform C${}_3$ cycle.

Mesophyll cells- Normal type of chloroplast. It has stacked thylakoids called granal chloroplast. The cells perform C${}_4$ cycle.

Hence, the correct answer is 'Agranal bundle sheath chloroplasts and granal mesophyll chloroplasts'.