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: Concept Overview:
The question seeks the biological term describing light's effect on seed germination.
Step 2: Detailed Analysis:
Analyzing each term:

Phototropism: Directional plant growth responding to light. Example: stem growth towards light. Related to growth, not germination.

Photoblasty: Seed response to light (presence or absence) for germination. Light-stimulated seeds are positively photoblastic (e.g., lettuce), while light-inhibited seeds are negatively photoblastic (e.g., onion). This aligns with the question.

Photonasty: Non-directional movement of plant parts (leaves, petals) responding to light intensity changes. Example: flower opening/closing.

Nyctinasty: Nastic movement related to the day/night cycle ("sleep movements"). Example: leguminous plant leaf folding at night.

Step 3: Conclusion:
Photoblasty is the correct term for sunlight's requirement in seed germination.