Plants (specifically photoreceptors and development) Flashcards
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What are Phytochromes?
receptors in the plant, mainly for red and far-red light
What receptors detect UV-A and blue light
cryptochromes and phototropins
What receptor detects UV-B
UVR8
What is the photoreceptor protein?
apoprotein
what is the small organic molecule that absorbs light?
chromophore
What are the two photo-interconvertible forms that phytochromes can exist in?
Pr (inactive) snd Pfr (initiates responses, when subjected to light)
When exposed to red light.. Pr transforms into ____
Pfr which activates a response, when far-red is detected reverts back
Explain shade avoidance
Canopies absorb red light.. with only far-red light filtering down to plants below. This is detected by phytochromes signalled smaller plants to grow into light
Why do plants flower when trying to grow into light
for seed dispersal as an alternative for reaching sunlight
How do plants detect neighbouring plants
the reflection of far-red light indicates proximity, telling plant to put resources into growing towards light.. to outcompete.
What are cryptochromes made up of and how do they function?
They bind flavin and pterin chromophores that absorb UV-A and blue light. Involved in controlling stem extension, gene expression and flowering time.
Both cryptochromes and phytochromes are necessary for..
light detection and growth
What are phototrophins made up of and how do they function?
Bind flavin chromophores that absorb mainly UV-A and blue light. Control responses like phototropism -> the direction of growth
What is the ABC model of flower morphogenesis?
The concept that A is needed for sepals and petals, B is needed for petals and stamens and C is needed for stamens and carpels. ABC all encode transcription factors
What is the ‘stress hormone’
ABA
What happens when ABA receptors detect ABA
closes stomata for reduced water loss
What can be used to measure ABA levels
Addition of fluorescent proteins for measurement. The more ABA the more fluorescence. (FRET)
What are ressurrection plants?
Plants that are able to come back from periods of drought. High levels of trehalose as a compatible solute for osmoregulation.
What does a compatible osmolyte help with?
lowers freezing point and over-expression increases salt tolerance and drought recovery.
What does modular mean in regards to plant development?
follows patterns that are repeated over and over
What does plasticity refer to in regards to plant development?
able to adapt/alter development. Laws are more like guidelines.. Apply to developmental modules
What is the first 4 stages in zygotic embryogenesis which give cell bulk?
The zygote -> 1 cell ->2-4 cell -> octant
What is the 5th stage of zygotic embryogenesis where cell layer separation takes place?
Globular
What are the last 3 stages of zygotic embryogenesis?
Heart (addition of shoot apical meristem (SAM) and root apical meristem (RAM) -> Torpedo -> bent cotyledonary
