Two kinds of plant movement

The idea

Plants have neither a nervous system nor muscles, and show two types of movement: one dependent on growth and the other independent of growth.

Touch me not

When you touch the leaves of a sensitive plant (chhui-mui), they fold up and droop at once. A seed in the soil, on the other hand, sends its root down and its stem up over days.

How are these two movements different?

• One needs growth and the other does not
• Both need growth
• Neither of them is a response to anything

Growth or not

Sort each plant movement into the right group.

Two ways to move

Plants have neither a nervous system nor muscles, yet they respond. If a seedling is prevented from growing, it will not show any movement. The sensitive plant can still move its leaves.

Plants have neither a nervous system nor muscles and show two types of movement: one dependent on growth and the other independent of growth.

Notes

Plants have no nervous system and no muscles, but they show two types of movement: one dependent on growth and the other independent of growth.

Check yourself

Which plant movement does not depend on growth?

What would happen if a germinating seedling were prevented from growing?

What do plants lack?

• A seedling's root going down. The directional movement of a seedling is caused by growth.
• A tendril circling around a support. A tendril circles because of different growth on its two sides.
• The leaves of a sensitive plant folding when touched — correct. Yes!
• It would not show any movement — correct. Yes!
• It would move faster. The seedling's movement is caused by growth, so without growth there is no movement.
• It would fold up like the sensitive plant. The sensitive plant's movement is independent of growth. A seedling's movement depends on growth.
• Any response to stimuli. Plants do respond to stimuli, with two types of movement.
• A nervous system and muscles — correct. Yes!
• Cells that change shape. Plant cells do change shape, by changing the amount of water in them.