Question

The physiological and morphological phenomena that happen when bulliform cells absorb water and undergo water stress respectively

• A. Flaccid: Leaf surface show no change.
  \phantom{(1)} Turgid: Leaf surface bend backward.
• B. Plasmolysed: Inward curling of leaf.
  \phantom{(2)} Turgid: No change.
• C. Plasmolysed: Inward curling of leaf.
  \phantom{(3)} Flaccid: Leaf surface exposed.

Hint:

Bulliform cells act like water sensors in grass leaves — when they lose water, the leaf curls to prevent further water loss.

Answer 1

The Correct Option is C

Bulliform cells are large, thin-walled cells present on the upper epidermis of grass leaves. They play a crucial role in water conservation and leaf folding/unfolding behavior in response to water availability.
- When bulliform cells are turgid (well-hydrated), they remain swollen, which keeps the leaf surface open and exposed to maximize photosynthesis.
- During water stress, these cells lose water, become plasmolysed, and shrink. This causes the leaf to curl inwards, reducing the surface area exposed to sunlight and minimizing water loss due to transpiration.
Hence, under water stress, the leaf curls inward due to the plasmolysis of bulliform cells. When the cells are turgid again after rehydration, the leaf unfolds and the surface becomes exposed.

Answer 2

Physiological and morphological phenomena related to bulliform cells under different water conditions:

Bulliform cells are large, bubble-shaped epidermal cells found mainly in the leaves of grasses. They play a crucial role in the folding and unfolding of leaves in response to water availability.

When bulliform cells absorb water, they become turgid (full of water). In this turgid state, the leaf surface is exposed and expanded, maximizing photosynthesis by increasing the leaf area exposed to sunlight.

During water stress or drought conditions, bulliform cells lose water and become plasmolysed, meaning the cell membrane shrinks away from the cell wall due to water loss. This causes the leaf to curl inward or fold, reducing the surface area exposed to the dry environment and thereby minimizing water loss through transpiration.

Hence, the physiological states and their corresponding morphological effects are:
- Plasmolysed bulliform cells: Cause inward curling of the leaf to reduce water loss.
- Flaccid (turgid) bulliform cells: Result in the leaf surface being exposed for maximum photosynthesis.

Correct Answer: Plasmolysed: Inward curling of leaf.
Flaccid: Leaf surface exposed.