Question

Where are auxins synthesized? How do they promote phototropism?

Answer 1

Step 1: Location of Auxin Synthesis:
Auxins are primarily synthesized in the apical meristem of the plant, specifically in the tips of the shoots and roots. They are produced in the growing regions of the plant, such as the tips of the stems, leaves, and flowers. The auxins then travel through the plant to influence growth and development.

Step 2: Role of Auxins in Phototropism:
Phototropism is the growth of plant parts in response to light. Auxins play a key role in promoting phototropism through the following mechanism:
- When a plant is exposed to light from one direction, auxins accumulate more on the shaded side of the plant stem or shoot.
- The higher concentration of auxins on the shaded side stimulates the cells to elongate more than the cells on the illuminated side.
- As a result, the plant bends toward the light source (positive phototropism), enabling it to maximize light absorption for photosynthesis.

Step 3: Conclusion:
Auxins are synthesized in the apical meristem and play a crucial role in phototropism by accumulating on the shaded side of the plant, promoting uneven cell growth and causing the plant to bend toward the light.