exam 4 shit i dont know

Procambium

Initiate where the new leaf will form

Stages of leaf senescence

1. Initiation: from nitrogen sink to source. Photosynthesis declines

2. Degenerative: cells break down

3. Terminal: cell death and leaf abscission

Monocarpic

Plant puts all its resources into one reproductive event and then dies. Usually annual or biennial plants.

Polycarpic

Perennials that reproduce many times in a life time

Evocation

When the plant is committed to flowering. Could still require secondary signal

Phase change

Meristem changes it fate from veg to flower

Plant phases

• juvenile

• Vegetative adult

• Reproductive

ARP genes

Encode myB transcription factors and antagonize KNOX genes functions in leaf polarity and structure

• aysemetric leaf 1

• Roughsheath2

• Phantastica

Totipotent

Versatile cells that can differentiate into any cell type

Pluripotent

Further into development, more restricted in differentiation potential

Coincidence model

Signal within circadian rhythms (CO) must coincide with daylight oscillations in 24hr period.

Constans (CO)

Long day - activator

Short day - inhibitor

Stable in the light and degrades with dark. Activates FT

Floral identity genes

• Leafy

• APATELLA1

Organ identity genes

ABC model

• A - APATELLA2

• B - APATELLA3/PISTILLA

• C - AGAMOUS

Central zone (SAM)

• slowly, dividing stem cells at top of the shoot

• Maintain stem cell pop

Peripheral zone (SAM)

• Cells on the edges

• Divide quickly

• Differentiate

Rib zone (SAM)

• cells in the middle

• Divide quickly

• Ground tissues and support

L1 layer (SAM)

Epiderm layer

L2 layer(SAM)

Ground tissue layer

L3 layer(SAM)

Internal tissues

Genes that control adaxial fate

ARP

Genes that control abacial fate

KANADI

Statoliths

Starch grains/amyloplast. Settle to bottom of cell in root cap to provide directional info

Expansions

Enzyme with acidic pH optimum that loosens cell wall polymers for expansion

3 phases of germination

1. Imbibition

2. Prep

3. Post germ ( radical free )

Monocot seed

Nutrients in starchy endosperm

Dicot seed

Nutrients in cotlyedon at maturity

Aleroune layer

Embryo produces GA and transfers to

the endosperm to convert starch to glucose

Alurone with GA stim amylase prod to