Question

In Kranz anatomy, the bundle sheath cells have
A. Thin walls, many intracellular spaces, and no chloroplasts
B. Thick walls, no intercellular spaces, and a large number of chloroplasts
C. Thin walls, no intercellular spaces, and several chloroplasts
D. Thick walls, many intercellular spaces, and few chloroplasts

Answer 1

Hint: The bundle sheath cells are a layer of cells that is present in the leaves and stems of plants that form a sheath that surround the vascular bundles. The Kranz anatomy means rings like anatomical structures present in \[{{C}_{4}}\] plants. It is a specialized structure where the mesophyll cells are clustered around the bundle-sheath cells. It is a structure having a ring-like fashion.

Complete answer: The \[{{C}_{4}}\] plants are those that undergo the photosynthesis process involving \[{{C}_{4}}\] photosynthesis mechanism. Many Angiosperm species, grasses, and hedges are examples of \[{{C}_{4}}\] plants. The Kranz anatomy denotes the arrangement of the mesophyll cells surrounding the bundle sheath cells. The bundle sheath cells are a layer of cells found in plant leaves and stems. These cells form a sheath around the vascular bundles. The bundle sheath cells consist of chloroplasts and are key sites of the Calvin cycle. The bundle sheath cells are involved in photosynthesis mediated by \[{{C}_{4}}\] photosynthesis mechanism. The products of photosynthesis are transferred from these cells to the adjacent phloem tissue. Then from vascular tissues, the products are transported to other parts of the plant. The bundle sheath cells are very different from the mesophyll cells. The bundle sheath cells have very small grana that are poorly developed. A lot of starch grains are present in the bundle sheath cells. The bundle sheath cells have thick walls as compared to mesophyll cells. Also, no intercellular spaces are present in the bundle sheath cells. A large number of chloroplasts are present in bundle sheath cells as they have localized Rubisco internalized in them that helps in carbon-dioxide fixation.
So, we can conclude that the right option is B.

Note: In the \[{{C}_{4}}\] photosynthesis mechanism involves the Calvin cycle in the bundle sheath cells and light-dependent reactions that occur in mesophyll cells. The RuBisCO stands for ribulose bisphosphate carboxylase oxygenase. Rubisco elements fix the carbon dioxide and help in the conversion of carbon dioxide into sugars.