Growth In Plants Flashcards
Where does cell division take place in plants?
In the root tips and shoot tips.
How can we estimate plant growth?
Measure root length or plant height. Or use a quadrat.
If you harvest the plant material within the quadrat, heat it on an_____ to drive off the water, then you have a measure of the dry _____ of the sample.
Oven
Weight
What happens if you cut off the shoot tip?
The shoot stops growing. But if you put the shoot back on it starts to grow again.
The shoot tip makes a hormone called _____. The hormone stimulates the shoot to grow. The hormone causes the cells to ______.
Auxin
Elongate
What are tropisms?
Plants respond to things like light, gravity and water. Parts of the plant either grow towards them or away from them.
How to plants grow towards one side ? (3)
- When a shoot only gets light from one side most auxin is found on the shaded side
- The auxin makes the shoot grow more on the shaded side
- The shoot bends towards the light
What is a phototropism?
When the shoot grows towards the light we say that they are positively phototrophic.
Why is that when a seed is planted the root always grows done and the shoot always grows up?
Shoot grows up away from gravity. Roots grow down towards gravity.
If a plant is put on its side the auxin builds up on the lower side of shoot and root. Explain this process.(5)
- In the shoot the auxin stimulates it to grow more on the lower side
- This causes the shoot to bend upwards
- In the root the auxin also builds up on the lower side. But auxin slows down growth in a root.
- So the upper side of the root grows quicker than the lower side
- The toot bends downwards
What is geotropism?
A growth response to gravity.
Roots are ______ geotropic while shoots are _______ geotropic.
Positively
Negatively
What does auxin also prevent?
Side shoots from forming.
What do you think would happen if the tip of the stem was removed?
The auxin will no longer be made so the side-shoots start to grow.
