Plant Hormones

All plants have a hormone in them called Auxin. This is distributed evenly throughout the plant. When a light source shines on the left side of a plant the auxin clusters on the right side of the shoot (stem) which tells the cells on the right side of the plant to grow faster causing the plant to bend towards the light. This reaction is called a photo-tropism. (when a plant reacts to light). it also causes an unequal growth rate.

Secondly if you were to lie a plant on its side in a pitch black room it would eventually end up pointing upwards. Why is this? Well because there is no light to "feed" the plant for photosynthesis it goes searching for it and the easiest way to find it is to go up. The auxin lines itself…