Question

Opening of cone in Cedrus deodar is favoured by one the following weather conditions.

• A. Wet
• B. Rainy
• C. Snowy
• D. Hot and sunny

Hint:

This dry-opening response is called xerochasy. It ensures that conifer seeds are released only when the air is dry and warm, which are optimal conditions for wind-assisted seed dispersal.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The seed dispersal of many coniferous gymnosperms, including Deodar (Cedrus deodara), relies on the physical opening of their woody cones.
This process is a physical response to environmental temperature and moisture conditions, designed to facilitate wind dispersal of seeds.

Step 2: Detailed Explation:
Conifer cones open through a hygroscopic mechanism:
- The woody scales of a Deodar cone absorb moisture under humid, wet, or rainy conditions, causing them to swell and remain tightly closed to protect the seeds inside.
- In contrast, hot and sunny weather with low relative humidity causes the scales to dry out and lose water.
- This drying causes unequal shrinkage between the upper and lower surfaces of the scales, pulling them outward and opening the cone.
- Once the cone scales open, the winged seeds are released and carried away by wind currents.
- Therefore, warm, dry, and sunny conditions are necessary to facilitate tural seed fall in Deodar forests, typically occurring in the autumn months.

Step 3: Fil Answer:
The opening of Deodar cones is favored by hot and sunny weather conditions.
Hence, the correct option is (D).