Which one among the following hormones stimulates the plant cells to grow in a manner such that the .plant appears to be bent towards light?

The hormone responsible for a plant bending towards light is auxin. Auxin is synthesized at the shoot tip and is sensitive to light [1]. When light comes from one side, auxin diffuses toward the shaded side of the shoot [1]. This higher concentration of auxin on the shaded side stimulates the cells there to grow longer and undergo more pronounced elongation compared to the cells on the illuminated side [1]. This differential growth causes the plant stem to curve or bend towards the light source, a phenomenon known as positive phototropism [2]. While other hormones like gibberellins promote general stem elongation and cytokinins promote cell division, it is specifically the redistribution of auxin that coordinates the directional growth response to light [4].

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Activity 6.2 > p. 108
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 6: Control and Coordination > Activity 6.2 > p. 107
3. [4] https://en.wikipedia.org/wiki/Phototropism