Question

Bending of stem/coleoptile towards light or shoot of potted plant placed near a window is due to

• A. Greater oxygen availability to the tip
• B. More auxin content on the shaded side
• C. Greater light availability to tip
• D. Availability of necessary warmth to the tip

Answer 1

The correct option is B More auxin content on the shaded side

Auxin is a plant hormone that plays important role in phototropism, growth movement in response to light. It promotes cell elongation. It is unequally distributed in the plant cells. It is transported towards the shady side and thus present in higher concentration. However, less auxin is transported towards the illuminated side. Due to this, the plant to grow more on the shaded side and bend in the direction of the light source. It shows phototropic response where faster cell elongation is seen on the shaded side than on the illuminated side.

Thus, the correct answer is option B.