How Plants Grow Auxins Not a Toxin What makes plants lean toward the light?
Even though plants are firmly rooted in the ground, they can still move as they respond to changes in their environment. Light is so important for plant growth that they actually “bend over backwards” to get their share! Think about it this way. The plant cells that are on the “shady” side of the plant actually grow longer than the cells on the “sunny” side. These longer cells grow this way because of a chemical in them called an auxin. An auxin, is a plant growth hormone that helps regulate shoot growth. Under normal light conditions auxins are spread out in the plant. But when sunlight varies, auxin is broken down on the sunnier side of the stem. The higher concentration of auxin on the shady side causes the plant cells on that side to grow more so it bends toward the light. Because light is the energy source for plant growth, plants have evolved highly sensitive mechanisms for perceiving light. That information regulates their development so they maximize the light they can take in
