Explain giving reasons the bending of the shoot tip of a plant towards light source coming from one side of the plant.
When growing plant shoot tip detects light a hormone called auxin is synthesised in the shoot tip which is sensitive to light.
Auxin diffuses towards the shady side of the stem.
It stimulates the growth of cells on the shady side of the plant which causes bending of the plant to the other side.
This gives the appearance that the stem of the plant bends in the direction of light.