Question

Seed Germination is induced by ________ but inhibited by ________

• A. Gibberellins (GAs)
• B. Abscisic acid (ABA)

Answer 1

Plant hormones:

1. Plant hormones are chemical compounds present in very low concentrations in plants. They are derivatives of indole (auxins), terpenes (Gibberellins), adenine (Cytokinins), carotenoids (Abscisic acid), and gases (Ethylene).
2. Hormones play an important role in processes like vernalization, phototropism, seed germination, dormancy, etc., and extrinsic factors.

Gibberellins :

1. There are more than 100 gibberellins (GA₁, GA₂, GA₃…..) that are known. They are acidic. These are found in higher plants and fungi.
2. Induces the formation of hydrolytic enzymes such as lipase, and amylase in the endosperm of germinating cereal grains and barley seeds.
3. It breaks seed dormancy.

Abscisic acid :

1. It is a growth-inhibiting hormone.
2. ABAs act as an antagonist to GAs.
3. It inhibits plant metabolism and regulates abscission and dormancy.
4. It is also called the “stress hormone” as it increases the tolerance of plants.
5. Induces abscission of leaves and fruits.
6. Inhibits seed germination.

Final Answer:

Seed Germination is induced by Gibberellins (GAs) but inhibited by Abscisic acid (ABA).