The main function of abscisic acid in plants is to inhibit growth.
Explanation: Abscisic acid (ABA) is often referred to as a “stress hormone” because it plays a key role in helping plants cope with adverse conditions like drought. One of its primary functions is to inhibit or slow down growth. It does this by preventing cell division, promoting the closure of stomata (tiny pores on leaves that regulate water loss), and inducing seed dormancy.
Why other options are incorrect:
A – Increase the length of cells:
Abscisic acid is not directly responsible for increasing cell length. While auxins are associated with cell elongation, ABA’s primary role is inhibitory.
B – Promote cell division:
Abscisic acid inhibits cell division, as mentioned in several sources. Cytokinins are the plant hormones responsible for promoting cell division.
D – Promote growth of stem and roots:
Abscisic acid inhibits growth, including stem and root growth. Its actions are more focused on preparing the plant for adverse conditions, such as seed dormancy and stomatal closure, rather than promoting active growth.