Question

What causes a green plant to bend towards light as it grows?

Answer 1

Phototropism:

1. The bending of growing plants towards the light is called phototropism.
2. By orienting their leaves and stems towards light plants receive the maximum energy for photosynthesis.
3. This process is mediated by a plant hormone called Auxin.

Mechanism:

1. Auxin is produced at the stem tip and promotes cell elongation.
2. When light falls on the plant, auxin moves to the darker side of the plant(Shaded region).
3. It causes the cells in that region(darker side) to grow larger than the cells corresponding to the lighter side of the plant.
4. This causes the plant to bend towards the source of light.