Insect-eating plants (Carnivorous plants) grow mainly in soils poor in nitrogen. They have evolved various methods of trapping insects and digesting their bodies to obtain nitrogen. Sundew is a tiny, reddish bog-plant with round or oval leaves covered in sticky hairs. Insects that land on the leaves cannot fly away and the hairs close around them. Digestive juices break down the insect's body and the leaf absorbs the nutrients. Bladderwort lives underwater. Its leaves have little bladders that open inwards by means of a tiny trap-door. Water fleas and other small creatures may swim into a bladder but they are unable to swim out again. They die, and the plant uses the products from their bodies. The pitcher plants are large, tropical species whose leaves are modified into flasks or pitchers. Insects that land on the rim slide into the flask over the slippery, waxy coating and drown in the liquid at the bottom of the flask.
Five basic trapping mechanisms are found in carnivorous plants.
1. Pitfall traps (pitcher plants): trap prey in a rolled leaf that contains a pool of digestive enzymes or bacteria.
2. Flypaper traps: use a sticky mucilage.
3. Snap traps: utilize rapid leaf movements.
4. Bladder traps: suck in prey with a bladder that generates an internal vacuum.
No comments:
Post a Comment