Question

Agranal chloroplasts are characteristic of
A. Mesophyll of pea leaves
B. Bundle sheath of mango leaves
C. Mesophyll of maize leaves
D. Bundle sheath of sugarcane leaves

Answer 1

A plant in which the$C{O_2}$ is first fixed into a compound containing four carbons atoms before entering the Calvin cycle of photosynthesis. Agranal means in which few rudimentary grana are present.

Step by step answer: Agranal chloroplasts are the characteristic feature of $C4$ plants. The agranal chloroplasts were found to be located in bundle sheath cells. Most of the $C4$ plants have special leaf anatomy called Kranz anatomy. Their vascular bundles are surrounded by two rings of cells, containing starch-rich chloroplasts lacking grana, which differ from those in mesophyll cells present as the outer ring. Plants possessing the $C4$-dicarboxylic pathway of photosynthesis are characterized by the presence of two types of chloroplasts, which differ in their structure, enzymic content, and pathway of photosynthesis. Chloroplasts of the mesophyll cells contain grana, while the mature chloroplasts of the bundle sheath cells are essentially agrannal. A $C4$ is better adapted than a $C3$ plants in an environment with high daytime temperatures, intense sunlight, drought or nitrogen or$C{O_2}$ limitation upon fixation of $C{O_2}$into a 4 –carbon compound in the mesophyll cells this compound is transported to the bundle sheath cells in which it is decarboxylated and the $C{O_2}$is re-fixed via $C3$ pathway. Pea and mango are $C3$plants which contain granal chloroplasts. Maize is a $C4$ plant and mesophyll of maize contains granal chlorophyll. Sugarcane is a $C4$ plant and bundle sheath of sugarcane leaves contains agranal chlorophyll.

Note: Examples of $C4$ plants include sugarcane, maize, sorghum, amaranth. The agranal bundle sheath chloroplasts are inactive in hill reaction, whereas granal bundle sheath and granal mesophyll chloroplasts exhibit normal photosystem II.