Question

How does auxin produce phototropism?

a. Auxin accumulates in cells on the side of the plant facing the source of light and stimulates their elongation.
b. Auxin accumulates in cells on the side of the plant facing the source of light and causes them to shorten.
c. Auxin accumulates in cells on the side of the plant opposite the source of light and causes them to shorten.
d. Auxin accumulates in cells on the side of the plant opposite the source of light and stimulates their elongation.

Answer 1

Auxin accumulates in cells on the side of the plant facing the source of light and stimulates their elongation.

Step-by-step explanation:

Auxin accumulates in cells on the side of the plant facing the source of light and stimulates their elongation. When light passes through a plant stem, it diffracts and generates phototropin activation across the stem. Most activation occurs on the lit side, causing the plant hormone indole acetic acid (IAA) to accumulate on the shaded side. Under the influence of IAA, stem cells elongate and the plant bends towards the light.