Answer to Question #104187 in Biology for NIBEDITA RUDRA

Question

Relative concentration of auxin in different parts of a seedling.

Answer 1

Auxin is one of the most important plant hormones that stimulate the cell division and overall growth of the plant tissues and organs. As a result, auxin can be found in all parts of a plant. However, the highest concentration of auxin is observed in the apical meristem of the stem and the root - tissues that provide the linear growth of the plant. Similarly, auxin concentration is high during seed germination as it induces seed germination. During the early stages of seeding, auxin concentration is high at the top of the growing shoot and root. During the further steps of plant growth, auxin concentration varies between the plant parts. When the stem is over the ground, auxin moves down away from the sun. As a result, its concentration increases on the dark surface of the shoot. Here, the extensive division and growth of cells lead to the overall growth of the stem toward the light. Auxin concentration is also high at the sites of the leaves formation. However, when the first leaves are at the stage of development, the concentration of auxin decreases in surrounding cells leading to the inhibition of the formation of new leaves near the developing leaves.