Question

Question 20
The substance that triggers the fall of mature leaves and fruits from plants is

(a) auxin
(b) gibberellin
(c) abscisic acid
(d) cytokinin

Answer 1

(c) abscisic acid

Abscisic acid is the plant hormone which inhibits growth. Its role is the abscission of plant leaves which include wilting of leaves. In preparation for winter, ABA is produced in terminal buds. This slows plant growth and directs leaf primordia to develop scales to protect the dormant buds during the cold season.