Plant Physiology Final Exam

Front 1

1. Biosynthesis occurs in ___
2. Largest amount is at the ____
3. Synthesized from_____

Back 1

1. leaf primodia, developing leave & seeds
2. shoot apex (stem tips)
3. amino acid tryptophan

Front 2

4. ____ auxin synthesis
5. _____ reporter gene is an auxin sensitive promoter

Back 2

4. Hydathodes
5. gus reporter gene

Front 3

6. gus stain blue moves where?

Back 3

towards sink and stimulates differentiation od xylem tissue

Front 4

Name both biologically active and inactive form of Auxin and state where it is stored and what is it associated with.

Back 4

Conjugated IAA = inactive
- stored in this form
conjugated with glucose, inositol, amides, glycoprotein

IAA - biologically active form

Front 5

Why is IAA degraded and what is used to degrade it?

Back 5

control devel.
oxidative degredation

Front 6

Name two subcellular pools of IAA

Back 6

cytosol and chloroplast

Front 7

IAA does not cross_____ and IAA conjugates are located in the ____

Back 7

membrane
cytosol

Front 8

Auxin is transported ____ from _____

Back 8

polarly from shoots to roots
requires energy and is gravity dependent

Front 9

Auxins move____ to the tissue below. Chemiosmotic model explains polar auxin transport ____ form of IAA move through________ concentrated on ________.

Back 9

basipitally
anionic form of IAA move through auxin transport carriers concentrated on basal end. Active and passive movement

Front 10

___ protein are carriers specifically transports IAA at basal ends of cells.
Where are these carriers cycled?

Back 10

PIN
cycled to membrane

Front 11

How does IAA move through sieve tube cells of phloem? Polar or nonpolar?

Back 11

Nonpolarly

Front 12

How do levels of IAA differ in regions of plants? What are the optimum concentrations in stem and root tissue?
What causes inhibition

Back 12

Optimum conc 10-5, 10-6 M stem tissue
Optimum conc 10-10, 10-12 for root tissue
higher conc than these causes stem inhibiiton

Front 13

name some physiological effxs of auxins:
(cells, stems, roots, cell wall, ect)

Back 13

cell elongation
promots growth in stems
inhibits growth in roots
rapidly increases extensibility of cell wall - 5 to 10 fold in 10 min. Wall loosening protien (expansisn) brks cellulose links under acidic condts.

Front 14

Acid growth hypothesis

Back 14

auxin rapidly increases extensibility of cell wall and increases cell extension

Front 15

Which protein inhibitor inhibits cell wall loosening

Back 15

cyclohexamide

Front 16

What does auxin do with ATPases?

Back 16

activates H ion atpases
synthesizes H ion atpases

Front 17

If the root cap was removed from the root apex and the root was
placed on a horizontal position, what results would you expect and why?

Back 17

Root tissue is more sensitive to IAA than stem tissue. IAA concentration on the bottom is so much it causes the root to bend down. If you cut off the root cap where IAA is located you don’t have the settling out of IAA so you don’t have root bending down. So if you were to lay the root apex on its side you would not have root bending down because no IAA present. Elongation of the root would cease.

Front 18

If the stem apex was cut from stem tip and replaced by a block of
agar, what results would you expect and why?

Back 18

IAA forms abscission zone and petioles die.

Front 19

If a leaf blade was removed from the end of its petiole and a paste
containing IAA was placed on the cut petiole, what results would you
expect and why?

Back 19

Transport of Auxin is basipetal in stems and leaves. Auxin always moves towards the base of stems and leaves so if you remove the blade and place auxin there, the petiole would grow.

Front 20

Cessation of wall expansions is____?
Secreted matrix polysaccharides are altered to _____
De-esterfication of pectins leads to _____
Cross linking of phenolic groups in the wall makes

Back 20

1. irreversible
2. form tighter complexes
3. more rigid pectin gels
4. for a more rigid cell wall

Front 21

auxin stimulates cell elongation in 1.
2. ____more sensitive to auxin
3._____may play a role in the lateral redistribution of auxin

Back 21

1. stems
2. roots
3. Root cap

Front 22

Name the hormone which regulates apical dominance.
Name two hormones which also play a role in apical dominance.

Back 22

1. auxin
2. cytokinin and ABA

Front 23

Name all of the things that auxin regulates

Back 23

1. apical dominance, 2. formation of both lateral and adventitious roots 3. fruit development: fruit set/ parthenocarpy

Front 24

What does auxin induce

Back 24

vascular differentiation

Front 25

What do High and low auxin concentrations stimulate

Back 25

1. high auxin conc = xylem and phloem tissue develope
2. low auxin conc = stimulate phloem differentiation

Front 26

What does auxin have to do with gravitropism? describe negative and positive types:

Back 26

gravitropism - roots grow down, shoots grow up.
(+) gravitropism = in root, no pin cells present in root to extend cells so gravity is only way to make extension.
(-) gravitropism = in shoot, cells on bottom extend longer than on top due to gravitropism.

Front 27

Why don't IAA elongate cells in stem?
2.Give an exp of IAA in root tissue
3.Is IAA settling out?

Back 27

cuz cells may not have genes there to develop pins & elongate

2.Root tissue more sensitive than stem tissue. IAA conc on bottom is so much it causes root to bend down. Plants are sensitive to hormone concentration so they try to have as little as possible.

3. No bc molecules are constantly moving, statoliths keep IAA in 1 place.

Front 28

ability of an organism  to detect day length

Back 28

Photoperiodism

Front 29

1.Shedding leaves, flowers, & fruits-
These abscised parts are (2)? .
After leaf abscission; differentiation of distinct layer of cells is called (3).

Back 29

1.abscission.
2. abscission zone
3. abscission layer

Front 30

Describe GA?

Back 30

A plant growth substance (phytohormone) involved in protion of stem elongation, mobilization of food reserves in seeds & ect processes. Its absence results in dwarfism of some plants. Family of diterpene acids made by terpenoid pathway in plastids and modified in ER & cytosol before reaching activated form. Orig derived from gibberella fungus

Front 31

GA synthesis controlled by?
How is GA sythesized ?

Back 31

Synthesis controlled by genes since dwarf plants are affected and
normal size plants are not affected by GA
Gibberellins are synthesized via the Terpenoid Pathway

Front 32

Where is GA made?

Back 32

largest conc made in developing seeds, and some in young leaves

Front 33

What molecules can GA be conjugated with

Back 33

other organic molecs - glucose

Front 34

Processes controlled by GA

Back 34

Photperiodism – Day length effects flowering in some plants
GA is synthesized during long days
Bolting - Cabbage plants, rosette forms under short day, undergo stem elongation and flowering only under long days.
Application of GA induces bolting.

Front 35

How does GA compare to auxins

Back 35

not polar, not at tips