Question

Leaf fall occurs when content of

• A. Abscisic acid decreases
• B. Auxin decreases
• C. Auxin increases
• D. Gibberellin decreases

Answer 1

The correct option is B Auxin decreases

Leaf abscission is a detachment or fall of older leaves.It occurs at the base of the petiole. It is observed that the intact leaf does not fall off because base of petiole of young leaf synthesizes auxin. During leaf fall, auxin content is low in the lamina as compared to stem. Also, ethylene content is high in the lamina during abscission.

So, the correct answer is 'Auxin decreases'