Question

The role of Bulliform cells in monocotyledonous leaves is :

• A. to prevent excessive transpiration by rolling of leaves
• B. to protect the mesophyll cells of the leaf
• C. in exchange of gases with the surrounding environment.
• D. in storage

Hint:

Associate "Bulliform cells" with "rolling leaves" in grasses. This is a mechanism to combat water stress. Think of it as the leaf folding up to protect itself from drying out.

Answer 1

The Correct Option is A

Step 1: Concept Overview:
This question concerns the primary function of bulliform cells, specialized cells present in the leaves of many monocot plants, especially grasses.
Step 2: Detailed Explanation:
Bulliform cells are large, thin-walled, highly vacuolated, bubble-shaped cells found in the upper (adaxial) epidermis of leaves. Their function is directly linked to the plant's hydration level.

Turgid State (Adequate Water): When well-hydrated, bulliform cells are full of water and turgid. This maintains the leaf blade's flatness, maximizing sunlight exposure for photosynthesis.
Flaccid State (Water Stress): When the plant experiences water loss (due to high transpiration or insufficient water uptake), bulliform cells lose turgor and become flaccid. This causes the leaf to curl or roll inwards, with the adaxial surface facing inward.
Leaf rolling reduces the surface area exposed to dry air, decreasing transpiration and helping the plant conserve water during drought. This is a hygroscopic movement.
Step 3: Conclusion:
The primary function of bulliform cells is to control leaf rolling and unrolling to manage water loss. Therefore, they help prevent excessive transpiration by inducing leaf rolling.