A portion of cross section of leaf is shown in the diagram. Answer the following:-
A) Label 1 to 4.
B) What kind of anatomy is shown in the diagram ?
C) Write the structure and function of 2 and 4.

Explanation

A) 1). Mesophyll cells 2) Mesophyll chloroplasts
3) Cells of bundle shealth. 4) Bundle sheath chloroplasts.
B) Kranz anatomy. This kind of anatomy occurs in the leaves of `C_(4)` plants in which the bundle-sheath cells are arranged in a wreath-like manner.
C) Structure and function of 2. Mesophyll chloroplasts: Mesophyll chloroplasts are granal and contain thylakoids that are stacked to form grana. These chloroplasts perform light reaction with the evolution of molecular `O_(2)`. The `CO_(2)` is fixed by phospho enol pyruvic acid to form 4 carbon oxalo acetic acid.

4. Bundle sheath chloroplasts are agranal, i.e., grana are absent and the thylakoids are present only as stroma lamellae. Bundle sheath chloroplasts perform `C_(3)` cycle in which the `CO_(2)` is fixed by RuBP catalysed by the enzyme RUBISCO (RuBISCO is present only in bundle sheath chloroplasts). `CO_(2)` is made available by decarboxylation of 4 carbon organic acid (malic acid).