Control in Plants
Plants are sensitive to light, moisture and gravity. Therefore when a plant
grows it will try to grow towards the light, and towards water. Sometimes
gravity can help the plant achieve this.
Plants growing with the light are known as phototropism, whereas a plant
growing with gravity is called geotropism. Different part of the plant will
respond to different things.The stem will respond to light but will not respond
to gravity. Therefore this is knows as positive phototropism and negative
The root of the plant is the opposite of the stem. It responds to gravity but
does not respond to light, as it is underground.Therefore it is knows as a
positive geotropism and negative geotropism.