Question

The requirement of sunlight for the germination of seeds, is known as:

• A. Phototropism
• B. Photoblasty
• C. Photonasty
• D. Nyctinasty

Hint:

Break down the words: 'Photo' relates to light. 'Tropism' is directional growth, 'nasty' is non-directional movement, and 'blasty' relates to germination or budding. This helps in differentiating between these similar-sounding terms.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
The question asks for the specific biological term that describes the effect of light on seed germination.
Step 2: Detailed Explanation:
Let's analyze the given terms:

Phototropism: This is the directional growth of a plant in response to a light stimulus. For example, a plant stem growing towards a light source. It relates to growth, not germination.

Photoblasty: This term specifically refers to the response of seeds to the presence or absence of light for germination. Seeds that are stimulated to germinate by light are called positively photoblastic (e.g., lettuce), while those whose germination is inhibited by light are negatively photoblastic (e.g., onion). This perfectly matches the question's description.

Photonasty: This is a non-directional movement of plant parts (like leaves or petals) in response to changes in light intensity. For example, the opening and closing of some flowers during the day and night.

Nyctinasty: This is a nastic movement related to the diurnal cycle (day and night), often called "sleep movements." For example, the folding of leaves of a leguminous plant in the evening.

Step 3: Final Answer:
The correct term for the requirement of sunlight for seed germination is photoblasty.