Which part of a plant is most likely to grow toward a light source due to phototropism?

• A. Lateral roots
• B. Shoot tip (apical meristem)
• C. Root tip
• D. Seed coat

Answer: (B)

Verified step by step guidance

1. Understand the concept of phototropism: Phototropism is the growth of a plant in response to light. Plants exhibit positive phototropism when they grow toward a light source, which is typically observed in shoots.
2. Identify the plant structure responsible for growth: The shoot tip, also known as the apical meristem, is the region of active cell division and elongation in plants. This area is highly sensitive to light and plays a key role in phototropism.
3. Examine the role of auxins: Auxins are plant hormones that regulate growth. In phototropism, auxins accumulate on the shaded side of the shoot, causing cells on that side to elongate more than those on the light-exposed side, resulting in the shoot bending toward the light.
4. Eliminate incorrect options: Lateral roots and root tips are involved in anchoring the plant and absorbing water and nutrients, but they do not exhibit phototropism. The seed coat is a protective layer and does not participate in growth toward light.
5. Conclude that the shoot tip (apical meristem) is the correct answer: Based on the understanding of phototropism and plant growth mechanisms, the shoot tip is the part of the plant most likely to grow toward a light source.