Plant hormones act away from the source

The idea

Plant hormones coordinate growth, development and responses to the environment; they are synthesised at places away from where they act and diffuse to the area of action.

Different places

A plant needs to grow in the right places and at the right times. It has no nerves to send orders.

How might a plant's chemical signal get from where it is made to where it is needed?

• It is made in one place and diffuses to the place where it acts
• It is made in the same cells where it acts, and never moves
• It is carried by nerves

Made here, acts there

Press Next step.

Away from home

A plant hormone does not act where it is made. It travels by simple diffusion.

Plant hormones coordinate growth, development and responses to the environment. They are synthesised at places away from where they act and simply diffuse to the area of action.

Notes

Plant hormones coordinate growth, development and responses to the environment. They are synthesised away from where they act and diffuse to the area of action.

Check yourself

Where are plant hormones synthesised compared with where they act?

How does a plant hormone reach the area where it acts?

What do plant hormones help to coordinate?

• At places away from where they act — correct. Yes!
• In the same cells where they act. Plant hormones are made away from where they act.
• Only in the roots. The book says they are made away from where they act. It does not limit them to the roots.
• It is carried along nerves. Plants have no nervous tissue. Hormones simply diffuse to the area of action.
• It simply diffuses there — correct. Yes!
• It is pushed by muscles. Plants have no muscles. Hormones diffuse to the area of action.
• Beating of the heart. This is an involuntary action in animals. Plant hormones coordinate growth, development and responses to the environment.
• Taste and smell. Taste and smell are detected by receptors of animals.
• Growth, development and responses to the environment — correct. Yes!