Corruzi 1

Front 1

Plant Growth

Back 1

Indeterminate - they can grow indefinitely because the constant presence of stem cells

Front 2

Plant Cell Potency

Back 2

Totipotent - carrot experiment

Front 3

Stem Cells in plants

Back 3

maintained in niches

root apical and shoot apical

Front 4

Stem Cell Niches

Back 4

stem cells are maintained as undifferentiated by short range diffusible signals from a localized cell source

As the stem cells divide and move away from the localized source, they lose the signal and differentiated

Front 5

Apical meristems

Back 5

Formed in the embryo, persist during adult life and contribute to indeterminate growth throughout plant life

Front 6

Shoot Apical Meristem

Back 6

Contributes to primary shoot growth at the tip of the shoots

Front 7

Leaves develop from...?

Back 7

Leaf primordia along the sides of the apical meristem

Front 8

Axillary Buds

Back 8

Form branches!

developfrom meristematiccells left at the bases of leaf primordia

Front 9

Root Apical Meristem

Back 9

Contributes to primary root growth

Root cap protects the RAM as it pushes through the soil

Front 10

3 zones of growth in RAM

Back 10

Differentiation, elongation, division

Front 11

Lateral meristems

Back 11

contribute to secondary growth (widening of the stem), i.e. in trees

Front 12

Vascular Cambium

Back 12

cylinder of meristematic cells 1-cell thick that give rise to secondary vascular tissues

e.g. xylem/phloem

Rings in trees come from this

Front 13

Plant cells grow through...

Back 13

Elongation: cell expansion accounts for actual increase in size

Division: cell division in meristems increase the potential for growth

Front 14

Cell division

Back 14

Theorientation ofthepreprophase microtubuleband determines the plane of cell division

anticlinal - transverse (horizontal)

periclinal - radial (vertical)

Front 15

Cell expansion

Back 15

Water uptake is the force for cell expansion

The direction is controlled by orientation of cellulose microfibrils - that orientation is dictated by microtubules in the cytoplasm

Front 16

Identification of mutations in arabidopsis

Back 16

Youcan identify the affected gene in a mutant by aligning the genetic map andphysical map (DNA)

Seeingdifferences in mutations and their distance between two mutants

Ifyou have a mutation and a piece of DNA with a restriction site, you can see cosegregation

Front 17

Cell Division /specialization

Back 17

An asymmetrical cell division precedes thedevelopment of epidermal guard cells, the cells that border the stomata onleaves.

2nd division makes stomata which openand close to allow in co2 in and air out

Unspecializedepidermal cell becomes specialized after asymmetricdivision –guard cell differentiates

Front 18

scrm-D mutant

Back 18

mutations in this make leaves that are made entirely of stomata

Scream mutant

There’seither a repressor that makes some cells not special which is mutated, or allcells are special unless they hear otherwise

Front 19

First asymmetric cell division sets up...

Back 19

shoot and root polarity

The first division of a plant zygote is asymmetricalandinitiates polarization intothe shoot and root

Front 20

gnom mutant

Back 20

defective in the asymmetric cell division - disrupts polarization into root and shoot

gnom controls polar auxin transport

Front 21

Phase shift in Shoot Apical Meristem

Back 21

gives rise to the floral apical meristem, from which all floral organs are derived

Front 22

Transition from SAM to FAM

Back 22

a derivative of a stem cell isdisplaced to the periphery of the shoot apical meristem,becomes part of a floralmeristem andis incorporated into a flower

Front 23

Whorl order (outer to inner)

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1. Sepal

2. Petal

3. Stamen

4. Carpel

Front 24

ABC model of development rules

Back 24

1. Each gene acts in 2 whorls

2. combinations of gene products determine whorl identity

3. genes A and C are mutually exclusive

Front 25

Gene A only makes:

Back 25

Sepal

Front 26

A+B

Back 26

Petal

Front 27

B+C

Back 27

Stamen

Front 28

C

Back 28

Carpel

Front 29

A mutant in Gene B has no:

Back 29

Petals or stamens

Front 30

A mutant in Gene A has:

Back 30

no petals or sepals (carpel, stamen, stamen, carpel)

Genes a and C mutually exclusive!!!!!

Front 31

A mutant in gene c has:

Back 31

no stamens or carpels (no gametes)

Front 32

ABC mutants support Goethe's idea that:

Back 32

thedifferent parts of a plant resultfrom transformation of a basic organ, the“idealleaf” intoother more specializedorgans (e.g.floral organs!).

Front 33

Superman Gene

Back 33

normally suppresses Gene B expression in whorl 4

A mutant in the superman gene makes the carpel become a stamen (2 stamens = super man)

Front 34

Functions of Floral Organs

Back 34

Sepal - enclose the flower

petal: brightly colored to attract pollinators

Stamen: male - produce pollen

Carpel: Female - produce ovules

Front 35

Double Fertilization process

Back 35

•Aftera pollen lands on a sigma, if pollination succeeds, a pollengrain producesa pollentube thatgrows down into the ovary and discharges two sperm cells nearthe embryo sac for double fertilization.

Front 36

Benefits of Double Fertilization

Back 36

Onesperm fertilizes the egg to make a zygote (2N), and the other sperm combineswith the polar nuclei, giving rise to the triploid food-storing endosperm(3n)

Hypothetically,one of the major benefits of double fertilization in angiosperms is to coordinatedevelopmental timing between the embryo and its food stores.

Front 37

Development of the Plant Embryo

Back 37

First mitotic division asymmetrical

-large basal cell forms suspensor cell

-terminal apical cell divides multiple times to form pro-embryo

•Aftergermination, apicaland root meristemssustain primary growth of seedling.

Front 38

Advantages of Seeds

Back 38

•Seed dormancy - Embryoalive but not growing. Seed isdesiccated yet protects embryo from drying out.•

Breakingof seed dormancy often requires environmental cues,such as water, temperature or lighting changes•

•This requirement increases the chancesthat germination and embryo growth willoccur at a time and place most advantageous to the seedling.