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Flashcards in Plant development Deck (20)
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1
Q

Name three stages of plant development in the shoot apical meristem and what they are resonsible for

A

Juvenile - for stem and juvenile leaves
Adult - stem and adult leaves
Reproductive - stem and flowers

2
Q

Difference between reproductive and vegetative SAM

A

Reproductive - produces floral meristem in flank

Vegetative - leaves in flank

3
Q

Are state changes reversible?

A

Normally not (in some cases can switch back to vegetative Calothamnus)

4
Q

Name four signals that can induce flowering in plants

A

Gibberelins
Photoperiod (daylight)
Vernalisation (cold spell)
Autonomous internal signalling

5
Q

What do maize plants flower in response to?

A

After having grown 6 leaves (can me modified to increase vegetative (id1 mutation)

6
Q

What is masting and in what plant species is it seen prominantly?

A

Where all individuals from same stock flower simultaneously regardless of location:0 bamboo

7
Q

What are the three stages of a vegetative meristem to expressing flowers?

A

Meristem is COMPETENT (Able to recieve signals via induction)
This leads to it being FLORALLY DETERMINED (it will flower regardless of location but then one more signal may be required to begin
EXPRESSION

8
Q

What are the main roles of miR156 and where is derived from?

A

Leaf derived microRNA (endogeonously produced) in abundance during juvenile phase. Suppresses adult leaf production and competence to flower

9
Q

What does miR156 respond to?

A

Sugar levels (sucrose accumulation blocks expression so then plant can move to adult phase)

10
Q

What is photoperiodism?

A

When a plant requires certain length days in order to induce flowering. These can be long or short days and are defined by the longest period of uninterrupted darkness.

11
Q

What hormone is responsible for flowering in plants and where is it formed and move through?

A

Florigen formed in leaves moves through phloem

12
Q

What did grafting with perilla (mint) leaf show (zeevart)?

A

That an induced leaf (response to stimuli) producing florigen can transmit this signal to uninduced plants multiple times! Florigen cannot be isolated.

13
Q

What are the roles of FT and FD in the flowering process?

A

FT is flowering locus T and is a small globular protein expressed in the phloem. It moves through here and into meristematic cells where it binds to FD transcription factor. Together they are both called the florigen activation complex and stimulate expression of APETALA1 gene.

14
Q

Where are fruits derived from?

A

gynoecium/female flowering parts

15
Q

What are the stages of fruit development?

A

Iniating - pollen shed
Anthesis - fruit begins to mature and grow
Breaker point- fruit stops growing and begins ripening NOT SENESCENCE

16
Q

What is thought to iniate ripening?

A

Short burst of CO2 production, called a respiratory climacteric. Fast ripening plants (avos) have bigger climacterics. However this excludes citrus fruits and others like melons.

17
Q

What is the role of ethylene in ripening?

A

ethylene promotes more ethylene production in climacteric plants and is assocaited with many of the gene expression pathways that produce ripening. This is only relevant to climacteric fruit. Non - climacteric are insensitve.

18
Q

Will addition of ethylene always result in ripening?

A

NO 1) not all plants are sensitive to it only climacteric fruits (apples pears amngos tomatoes). 2) fruit must be competent first (reached breaker point). If applied befre then it actually delays ripening (system 2 response as opposed to system 1 which is ripening)

19
Q

Why is ethylene production a problem?

A

Can result in psot harvest losses of up to 100% TOMATOES

20
Q

How is RIN mutation used in tomato production?

A

Heterozygotes with this mutation have the ACC synthase enzyme affected stopping the biochemical pathway to ethylene. They still stay firm and sweet however but can last 10-14 days longer!