8 co-ordination in plants Flashcards
what is the shaded side where IAA will move to called?
zone of elongation
where is IAA produced?
in the stem tip
how does IAA move down plant?
DIFFUSION
what is IAA?
a type of auxin which is a growth regulator
what causes cells to elongate?
- vacuoles develop as more water intake due to osmosis
- cellulose wall stretches
- vacuoles merge
why do plants in the dark still grow upwards?
-gravitropism, the plant will respond to gravity not light
what are the two types of plant photoreceptors called?
Pred and Pfar-red
the absorption of per indicates the plant is ________.
in the shade
how will a plant know when to germinate?
- light contains Pr
- more Pr absorbed and turned into Pfr
when is the speed of Pfr to Pr slow?
in the dark
what is Pfr?
a transcription factor
what is meant my transcription factor?
-Pfr enters the nucleus and activates or represses transcription of certain genes
what can Pfr regulate?
- seed germination
- stem elongation
- leaf expansion
- flowering
- chlorophyll formation
what type of plant needs low levels of Pfr to flower?
short-day plants
why will long day plants flower when it has high levels of Pfr?
high levels of Pfr mean high levels of Pr to have been before, this is a very rapid conversion in the light so if there is more Pfr then there is more time for this to occur, so the day must be longer
