Question

What type of dormancy is caused by impermeable seed coat?

• A. Physical dormancy
• B. Physiological dormancy
• C. Endogenous dormancy
• D. Thermo dormancy

Hint:

Physical seed coat dormancy can be broken by scarification methods, such as mechanical abrasion, hot water treatment, or acid treatment, which create micro-cracks in the seed coat to allow water uptake.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Seed dormancy is an evolutiory adaptation that prevents seeds from germiting during unfavorable ecological conditions.
Dormancy is classified based on the atomical or physiological mechanism that prevents germition.

Step 2: Detailed Explation:
Let us alyze the different dormancy types:
• Physical dormancy: This is caused by structural properties of the seed coat (or fruit wall) that make it impermeable to water, oxygen, or both. It is common in families like Fabaceae and Malvaceae. Without water absorption, the physiological processes required for germition cannot begin.

• Physiological dormancy: This is caused by chemical inhibitors within the embryo or surrounding tissues, or by an imbalance in plant hormones (such as abscisic acid and gibberellins).

• Endogenous dormancy: This is caused by factors within the embryo itself, such as an underdeveloped embryo or physiological inhibitors.

• Thermo dormancy: This is a type of secondary dormancy induced by exposure to high temperatures.
Since seed coat impermeability is a physical barrier, it is classified as physical dormancy.

Step 3: Fil Answer:
The correct option is (A).