Question

The main function of bulliform cells in grasses is :

• A. To make leaf impermeable
• B. To perform photosynthesis
• C. To minimize water loss
• D. To transport water

Hint:

Bulliform cells act like "Hydraulic Hinges" that fold the leaf to save water!

Answer 1

The Correct Option is C

Step 1: Understanding the Question
This question focuses on the anatomical adaptations of grasses (monocots). It asks for the primary function of "bulliform cells," which are specialized, large, bubble-like epidermal cells found on the upper leaf surface. Step 2: Key Formula or Approach
The approach is based on plant physiology and the concept of turgor pressure. Bulliform cells act as "motor cells" that change the physical shape of the leaf based on its hydration status. Step 3: Detailed Explanation
Location and Appearance: Bulliform cells are large, empty, colorless cells located in the upper epidermis along the veins of grass leaves.
Response to Water Availability: When water is abundant, these cells absorb it and become turgid. This turgidity causes the leaf blade to expand and lie flat, exposing its surface for photosynthesis.
Response to Water Stress: During periods of drought or high evaporation (water stress), these cells lose water and become flaccid.
Leaf Curling Mechanism: When they become flaccid, they cause the leaf to roll or curl inward. This action hides the leaf's stomata from the air and sunlight.
Final Outcome: By rolling up, the surface area exposed to the environment is reduced, which significantly decreases transpiration and prevents the plant from drying out.
Step 4: Final Answer
The primary role of bulliform cells is to cause leaf rolling, which helps to minimize water loss during periods of water stress. Thus, (D) is the correct answer.