Immediate response without growth
Cells swell or shrink to move a leaf.
A quick fold
A sensitive plant folds its leaves the moment it is touched. The touch is at one place, but the leaf bends at another place. The plant has no nerves and no muscles.
How do you think the plant moves its leaves?
What this lesson covers
The idea
In movement without growth, plants pass information from cell to cell by electrical-chemical means with no specialised tissue, and cells change shape by changing their water content, swelling or shrinking.
A quick fold
A sensitive plant folds its leaves the moment it is touched. The touch is at one place, but the leaf bends at another place. The plant has no nerves and no muscles.
How do you think the plant moves its leaves?
- Its cells change shape by changing their water content
- Special muscle proteins pull the leaves shut
- Nerves carry the message to a brain
Touch and fold
Press Next step to follow the touch.
Water moves the leaf
The plant has no muscle proteins. It changes the water in some cells so that they swell or shrink, and that changes their shape.
In movement without growth, plants pass information from cell to cell by electrical-chemical means, with no specialised tissue. Cells change shape by changing the amount of water in them, swelling or shrinking.
Notes
In movement without growth, plants pass information cell to cell by electrical-chemical means with no specialised tissue, and cells change shape by changing their water content, swelling or shrinking.
Check yourself
How does a sensitive plant pass information that it has been touched?
How do plant cells change shape in this kind of movement?
A leaf bends at a point far from the point of touch. What does this show?
- Along nerves, as in animals. Plants have no nervous tissue.
- Through a specialised tissue made for conducting information. Plants have no specialised tissue for the conduction of information.
- From cell to cell by electrical-chemical means — correct. Yes!
- By changing the amount of water in them, so they swell or shrink — correct. Yes!
- By special proteins, as in animal muscle cells. Plant cells do not use the special proteins found in animal muscle cells. They change the amount of water.
- By growing new cells in one direction. This movement involves no growth.
- The plant did not detect the touch. The leaf did move, so the touch was detected and the information was passed on.
- Information that a touch occurred is communicated from one place to another — correct. Yes!
- The plant used a nervous system. Plants have no nervous system. They pass information from cell to cell by electrical-chemical means.