Question

The substance that triggers the fall of mature leaves and fruits from plants is due to

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

Answer 1

The correct option is C

Abscisic acid

The correct option is C.

Explanation of the correct option:

• The falling of mature leaves and fruits from plants is called abscission. It is caused by a hormone called abscisic acid.
• This hormone inhibits a plant's growth by acting against growth-promoting hormones.
• It also causes seed dormancy and leaf wilting during harsh conditions.

Explanation of the incorrect options:

Option A:

• Auxin does not cause the leaves and fruits to fall. This hormone promotes growth in the shoots and roots.

Option B:

• Gibberellin causes elongation of the plant cells. It does not cause the fall of leaves and fruits.

Option D:

• The fall of leaves and fruits is not caused by cytokinin. Cytokinin promotes the division of plant cells.

Final Answer: Therefore, the substance that causes the fall of mature leaves and fruits is abscisic acid.