Question

Chloroplast dimorphism is a characteristic feature of
a. Plants with Calvin cycle
b. $C_4$ plants
c. All plants
d. Only in algae

Answer 1

Hint: The chloroplast dimorphisms refer to the presence of two types of chloroplasts in a single plant. It is found in sugarcane. The calvin cycle occurs in C3 plants. The bundle sheath cells of these plants do not contain chloroplast.

Complete answer:
The chloroplast which is concentrated into two types of cells having different size and structure are called dimorphic chloroplasts. It is found in mesophyll cells having grana.

The characteristic feature of $C_4$ plants is called Chloroplast dimorphism. For ex:- Amaranthus, sugarcane, maize, etc. The $C_4$ plants have two types of chloroplasts: one for fixing $CO_2$ and the other that allows RubisCo to function at increased $CO_2$ partial pressure. The bundle sheath cells of these plants contain chloroplast. The carbon dioxide fixation takes place twice in $C_4$ plants.

The calvin cycle is also known as C3 cycle. Plants which show this cycle are known as C3 plants. Their chloroplast is uniform with respect to photosynthesis. The bundle sheath cells do not contain chloroplast in these types of plants.

From the above information we have found that chloroplast dimorphism is a characteristic feature of the $C_4$ plants.

Hence, the correct answer is option (B).

Note: The $C_4$ plants are adapted to dry and hot environments. They include maize, sorghum, and tropical savanna grasses and sedges also. The RUBISCO is found in bundle sheath cells in $C_4$ plants which play a vital role in carboxylations. The leaves of $C_4$ plants show kranz anatomy. In this type of anatomy, the tissues are equivalent to spongy mesophyll cells clustered in a ring around leaf veins outside the bundle sheath cells.