NEET 2025 MCQ with Answer : “Plant growth and Developement”.

Here below some basic MCQ’s of plant growth and developement with answer which is explained in details. Let’s check one by one which is given below.

1. Which of the following hormones promotes cell division in plants?
   a) Abscisic acid
   b) Gibberellins
   c) Cytokinins
   d) Ethylene

Answer: c) Cytokinins

Explanation:
Cytokinins are plant hormones that promote cell division (cytokinesis) in plant roots and shoots. They also influence the growth of shoot buds and delay the aging of leaves.

2. Which phase of growth is characterized by slow growth at the beginning and end, with rapid growth in between?
   a) Exponential phase
   b) Lag phase
   c) Stationary phase
   d) Log phase

Answer: a) Exponential phase

Explanation:
The exponential phase (also known as the log phase) represents the period of rapid growth, where cells divide at an exponential rate. In the S-shaped sigmoid growth curve, this phase is observed between the lag phase (slow growth at the beginning) and the stationary phase (slowing down towards the end).

3. Vernalization is required for which of the following?
   a) Seed dormancy
   b) Induction of flowering
   c) Fruit ripening
   d) Apical dominance

Answer: b) Induction of flowering

Explanation:
Vernalization is the process of inducing flowering in plants by exposing them to prolonged cold temperatures. This treatment helps certain plants flower in spring after a cold winter.

4. Which of the following is NOT a plant growth regulator?
   a) Ethylene
   b) Auxin
   c) Gibberellin
   d) Glucose

Answer: d) Glucose

Explanation:
Glucose is not a plant hormone but a product of photosynthesis. Ethylene, auxin, and gibberellin are all plant growth regulators that play a role in various developmental processes in plants.

5. Photoperiodism is the response of plants to:
   a) Temperature changes
   b) Day and night length
   c) Soil moisture
   d) Atmospheric pressure

Answer: b) Day and night length

Explanation:
Photoperiodism is the physiological reaction of organisms to the length of day or night. In plants, it influences processes like flowering, with some plants being short-day plants, long-day plants, or day-neutral.

6. Which plant hormone is known as the “stress hormone”?
   a) Auxin
   b) Abscisic acid
   c) Gibberellin
   d) Cytokinin

Answer: b) Abscisic acid

Explanation:
Abscisic acid (ABA) is called the stress hormone because it plays a key role in helping plants respond to environmental stress, particularly drought, by inducing stomatal closure to conserve water.

7. What is the primary effect of auxins in plants?
   a) Promote fruit ripening
   b) Inhibit seed germination
   c) Stimulate stem elongation
   d) Delay leaf senescence

Answer: c) Stimulate stem elongation

Explanation:
Auxins are primarily involved in promoting cell elongation, especially in the stems, and are responsible for phototropism and gravitropism, helping the plant grow towards light and against gravity.

8. Which of the following is required for the synthesis of gibberellins in plants?
   a) Light
   b) Nitrogen
   c) Phosphorus
   d) Water

Answer: a) Light

Explanation:
Light is an important environmental factor for the synthesis of gibberellins, which play a key role in seed germination, stem elongation, and flowering.

9. Which plant hormone is associated with the ripening of fruits?
   a) Gibberellin
   b) Auxin
   c) Ethylene
   d) Cytokinin

Answer: c) Ethylene

Explanation:
Ethylene is a gaseous plant hormone that regulates the ripening of fruits. It also plays a role in leaf abscission and flower senescence.

10. The process of seed germination is initiated by:
    a) Ethylene
    b) Gibberellins
    c) Abscisic acid
    d) Cytokinins

Answer: b) Gibberellins

Explanation:
Gibberellins are crucial in breaking seed dormancy and initiating germination by promoting the synthesis of enzymes that digest stored food in the seed, making energy available for growth.