Tropism

When plants “react”!

TropismAll living things respond or react to their

environment.–temperature–weather–other organisms

Plants also react to stimuli. This is called tropism.

What is tropism?

The way a plant behaves due to certain environments.

Example: Look at your eco-columns.• Growth towards the sunlight• Roots always grow down

Sunlight

Plants react to sunlight. The sides away from the sun grow longer and the plant starts to bend towards the

light.

Darkness

Other plants may react from darkness or lack of light. Morning glories close up at night when they react from the lack of sunlight.

Gravity

Like everything else on Earth, plants also respond to gravity. A plant’s roots grow down into the soil due to the pull of gravity.

This also anchors the plant into the ground.

Venus Fly TrapThese plants are very different

from normal plants.1) Since they eat insects and

meat,

2) They respond to touch. When something touches one of its sticky hairs, they bend and trap the animal inside.

they are consumers.

Touch

Another plant that responds to touch is the mimosa plant. This Hawaiian fern plant closes up when touched.