Which one among the following hormones inhibits the growth activity in plants?

Plant hormones, or phytohormones, are chemical messengers that regulate growth and development. While auxins, gibberellins, and cytokinins are primarily growth promoters, abscisic acid (ABA) acts as a growth inhibitor [1]. Auxins promote cell elongation and shoot growth, gibberellins stimulate stem elongation and break seed dormancy, and cytokinins promote cell division [1]. In contrast, abscisic acid is often referred to as the 'stress hormone' because it signals the plant to stop growing under unfavorable conditions. Its primary functions include inducing seed dormancy, promoting the wilting of leaves, and signaling stomatal closure to conserve water during drought [1]. By inhibiting growth and metabolic activity, ABA helps the plant survive environmental stress by balancing growth with adaptation [2]. Therefore, among the given options, abscisic acid is the hormone responsible for inhibiting growth activity [1].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Activity 6.2 > p. 108
2. [2] https://www.sciencedirect.com/science/article/pii/S2773126X25000413