Grass leaves curl inward during very dry weather. Select the most appropriate reason from the following:
- Shrinkage of air spaces in spongy mesophyll
- Tyloses in vessels
- Closure of stomata
- Flaccidity of bulliform cells
Answer
(4) Flaccidity of bulliform cells
Solution
As per NCERT, in grasses certain adaxial epidermal cells along the veins modify into large, empty, colourless bulliform cells.
∵ When the bulliform cells have absorbed water and are turgid, the leaf surface is exposed; when they are flaccid due to water stress,
∴ the leaves curl inwards to minimise water loss.
Answer: (4)