Chemotropism
Pollen tubes grow towards ovules.
A long journey
A grain of pollen lands on the top of a flower. Far below it, inside the flower, is a part called the ovule.
What do you think the pollen grain grows to reach the ovule?
What this lesson covers
The idea
Chemotropism is a tropic movement shown by the growth of pollen tubes towards ovules.
A long journey
A grain of pollen lands on the top of a flower. Far below it, inside the flower, is a part called the ovule.
What do you think the pollen grain grows to reach the ovule?
- A tube that grows towards the ovule
- Legs that carry it down
- A wing that flies it down
Towards the ovule
Press Next step. This is a simple drawing of one flower.
One more tropism
Chemotropism is another tropic movement, a direction of growth set by a trigger. Here the growth is towards the ovule. You will learn more about it with reproduction.
Chemotropism is a tropic movement shown by the growth of pollen tubes towards ovules.
Notes
Chemotropism is a tropic movement shown by the growth of pollen tubes towards ovules.
Check yourself
Which is an example of chemotropism?
Chemotropism is what kind of movement?
Pollen tubes grow towards what?
- The growth of pollen tubes towards ovules — correct. Yes!
- Roots growing downwards. This is geotropism, a response to the pull of the earth.
- Shoots bending towards light. This is phototropism, a response to light.
- A quick folding movement with no growth. Tropic movements involve growth. The quick folding of a sensitive plant does not.
- A tropic movement, which is a directional growth movement — correct. Yes!
- A reflex action of the spinal cord. Plants have no nervous system. Chemotropism is a tropic movement.
- The light. Shoots bend towards light in phototropism. Pollen tubes grow towards ovules.
- The pull of the earth. The pull of the earth directs roots and shoots in geotropism. Pollen tubes grow towards ovules.
- Ovules — correct. Yes!