Free Forms and Functions of Plants MCQs with Answers

1. In plants the _ waste product is used in the chemical processes, they are not removed from the body.

• A. Ions
• B. Water
• C. Oxygen
• D. Nitrogenous

Explanation: Oxygen, a byproduct of photosynthesis, is either used by the plant in respiration or released into the atmosphere.

2. Gibberellic acid induces flowering:

• A. In short-day plants under long-day conditions
• B. In day-neutral plants under dark conditions
• C. In some gymnospermic plants only
• D. In long-day plants under short-day conditions

Explanation: GA can replace the long-day requirement, inducing flowering in long-day plants under short days.

3. Organization of the stem apex into corpus and tunica is determined mainly by:

• A. planes of cell division
• B. Regions of meristematic activity
• C. Rate of cell growth
• D. Root of shoot tip growth

Explanation: The tunica and corpus are distinguished by the direction of cell divisions. Tunica cells divide mainly anticlinally, while corpus cells divide in various planes, determining their organization.

4. For the union between the stock and the scion in grafting, which one is the first to occur?

• A. Formation of callus
• B. Production of plasmodesmata
• C. Differentiation of new vascular tissues
• D. Regeneration of cortex and epidermis

Explanation: Callus forms first, later differentiates into vascular connections.

5. During seed germination, its stored food is mobilized by:

• A. ABA
• B. Gibberellin
• C. Ethylene
• D. Cytokinin

Explanation: GA stimulates amylase → starch → sugars for seedling energy.

6. Photoperiodism was first characterized in:

• A. Tobacco
• B. Potato
• C. Tomato
• D. Cotton

Explanation: Garner & Allard (1920s) studied flowering response to day length.

7. Coiling of garden pea tendrils around support is an example of:

• A. Thigmotaxis
• B. Thigmonasty
• C. Thigmotropism
• D. Thermotaxis

Explanation: Directional growth in response to touch.

8. Root development is promoted by:

• A. Abscisic acid
• B. Auxin
• C. Gibberellin
• D. Ethylene

Explanation: Auxin induces adventitious root formation.

9. Senescence as an active developmental process is indicated in:

• A. Annual plants
• B. Floral parts
• C. Vessel and tracheid elements
• D. Leaf abscission

Explanation: Xylem elements undergo programmed cell death during differentiation.

10. Opening of floral buds into flowers is a type of:

• A. Autonomic movement of variation
• B. Paratonic movement of growth
• C. Autonomic movement of growth
• D. Autonomic movement of locomotion

Explanation: Occurs due to internal growth processes.