Question

explain in brief the cause of a plant shoot bending towards light

Answer 1

Under normal light conditions auxins are spread out in the plant. But when sunlight varies, auxin is broken down on the sunnier side of the stem. The higher concentration of auxin on the shady side causes the plant cells on that side to grow more so it bends toward the light.

Answer 2

The growth of a plant towards the light source is known as phototropism. It occurs in plants due to the presence of hormone auxin which is highly light sensitive. As sunlight falls on one side of the shoot, auxin gets stimulated and generally it diffuses to the shaded portion of the plant. It starts elongating the cells of the shaded portion. Thus the shaded portion grows and elongates more than the illuminated part. As a result the curvature of the plant stem tip bends towards the light.