Education Zone

How we use our knowledge of tropisms and etiolation

	Stacked trays of cress are placed in a germination room. The root growth can be controlled by altering conditions within the room. A fine fog is created in the room. The abundance of water in the air causes the root hairs to develop at a faster rate, due to them not having to search for water. Lights are used to encourage the shoots to develop.
	After 48 hours the seedlings become etiolated (Pale and stretched) The seedlings now require more light than is available in the germination room.
	The trays are laid out on greenhouse benching. The abundance of light allows them to produce more chlorphyll, the seedlings quickly become green and a larger leaf develops. The crop is watered using irrigation booms, because the water soaks through to the peat, the roots now grow down.