Plant Hormones Flashcards
What are auxins and what do they do
They are hormones that change growth patterns to allow roots and shoots to move either towards or away from a stimulus
What are tropisms
Response to stimuli that involve directional growth
What is ethene
A gas that controls cell division, and the rip ending of fruits
What is ethene used for
Ethene is used in the food industry to control the ripening of fruit during storage and transport.
What are gibberellins and what are they used for
Gibberellins are hormones that
-> promote flowering
-> initiate seed germination
-> increase fruit size
-> ending seed dormancy
What are auxins used to do (industrially)
-> kill weeds
-> rooting powders
-> promote growth in tissue culture
What is negative and positive phototropism
Positive phototropism - growing towards light
Negative phototropism - growing away from light
What is positive and negative gravitropsim
Positive gravitropism - growing following gravity
Negative gravitropism - growing agains gravity
What processes in plants are controlled by hormones
- flower opening
- germination
- shedding if leaves
One pot is placed under window, and other is grown by a window next to it
The one under the window has grown straight up, the one next to the window have grown to the side
The brother says that the one under the window does not have any tropism, and the sister says the one next to the window has positive phototropism
Why is the brother wrong
-> though the light comes from above, the leaves are still positively photographic as they are growing in the direction of the lighting
-> the sisters answer is better as she is right about the leaves being positively phototropic
Why are plant hormones used to cause parthenocarpic fruit development?
To produce seedless fruit
Describe how a selective herbicide works (2 marks)
Contains hormones called auxins that cause rapid cell growth and elongation.
Describe an effect of gibberellins hormones in plants
Breaks seed dormancy and promotes flowering
There are thee plants, one normal, one with a cut tip and one with a cap. What can be said about them
-> only the normal one is positively phototropic
-> all of the seedlings respond to gravity
The difference between a normal plant and a plant with the tip cut off is due to a plant hormone
Explain why
-> the normal seedling grows toward the light due to a hormone called auxins that cause, which is made in the top of the seedling
-> the second seedlings tip has been cut off, meaning no auxin is produced and the shaded side is unable to bend to the light
