Question

Dimorphic chloroplasts are present in
A. Sugarcane
B. Cotton
C. Pea
D. Mango

Answer 1

Dimorphic chloroplasts means the occurrence of two different kinds of chloroplasts in a plant. The dimorphic chloroplasts are present in the ${C_4}$ plants. Moreover, sugarcane is an example of a plant with the ${C_4}$ cycle.

Complete answer:
${C_4}$ plants: ${C_4}$ plants have a special cycle of photorespiration known as the ${C_4}$ cycle due to which they are known as the ${C_4}$ plants. This cycle was discovered by the American scientists Hatch and Slack. ${C_4}$ plants have special leaf anatomy known as the Kranz anatomy. Kranz anatomy consists of bundle sheath cells which are large in size and compactly arranged. These cells are surrounded by the mesophyll cells which are smaller in size and loosely arranged. Due to this reason ${C_4}$ plants have dimorphic chloroplasts. Dimorphic chloroplasts are the chloroplasts that are present in two types of cells which have varying size and structure. Examples of ${C_4}$ plants –
Monocot plants – Maize, Sugarcane, Sorghum.
Dicot plants – Euphorbia, Chenopodium, Atriplex, Amaranthus.
Thus, the dimorphic chloroplasts are present in Sugarcane.
Hence, the correct answer is option (A).

Note: Mesophyll cells have granal chloroplasts. They do not have any RUBISCO enzyme present. Due to this, no ${C_3}$ cycle occurs here. On the other hand, Bundle sheath cells contain granal chloroplasts and RUBISCO enzymes. Due to this, the ${C_3}$ cycle is present here. Moreover, the fixation of the carbon dioxide occurs by the cooperation of both the Mesophyll cells and the Bundle sheath cells.