Auxins are a group of plant hormones that play a crucial role in plant growth and development. They are primarily involved in cell elongation, regulating the formation of roots and shoots, and mediating tropic responses such as phototropism.
Phototropism is a plant's directional growth response to light. It is the process by which plants bend or curve towards a light source. This response occurs due to the redistribution of auxins in the plant tissue.
When light is perceived by the plant, it triggers an increase in auxin concentration on the shaded side of the stem or shoot. This higher concentration of auxin promotes cell elongation, causing the stem to bend towards the light source.
The mechanism behind phototropism involves the movement of auxins from the shoot apex downwards. In response to light, auxins accumulate on the shaded side of the plant, inhibiting cell elongation in that region. Meanwhile, the illuminated side of the plant has lower auxin concentration and experiences normal cell elongation. This difference in auxin distribution leads to bending towards the light.
Overall, auxins regulate phototropism by promoting cell elongation on one side of the plant and inhibiting it on the other, resulting in the bending movement towards the light source.
AUXINS AND PHOTOTROPISM
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