Lecture 5

Question 1

Secondary growth

Answer 1

• growth in width, makes it woody
• caused by lateral meristems: pro cambium and the cork cambium
• only occurs in edicts

Question 2

Expain secondary growth

Answer 2

-Has to go through primary growth first
After primary growth, pro cambium develops into lateral meristem: vascular cambium
-Cortex develops into cork cambium
-vascular cambium produces secondary xylem to inside (wood) and secondary phloem to the outside via the fusiform initials. also makes rays
-Cork cambium produces cork to outside, phelloderm to inside

Question 3

vascular cambium

Answer 3

-makes secondary xylem and phloem
-makes wood
-one cell thick
-consists of fusiform initials: tracheas and vessel elements
ray initials: rays

Question 4

WOOD

Answer 4

secondary xylem
-lignified
-to inside
heartwood: dark old centre, sends toxins to it so it prevents rooting
sap wood: light young outside, fluid movement. has growth rings and rays
-lignin in secondary walls

Question 5

Spring and fall

Answer 5

spring has very wide vessel elements and tracheas

fall has very narrow

Question 6

amount of growth rings

Answer 6

determines amount of years

Question 7

name the order/ draw wood

Answer 7

secondary xylem, vascular cambium, secondary phloem, cork cambium, cork

Question 8

periderm

Answer 8

cork and cork cambium

Question 9

bark

Answer 9

everything outside vascular cambium

secondary phloem and cork cork cambium

Question 10

2nd law of thermodynamics

Answer 10

-energy spontaneously flows from areas of high to low concentration. thats how plants move fluids

Question 11

Summary of xylem flow

Transpiration-Tension-Cohesion Hypothesis

Answer 11

1) Water pulled out of the moist cells of stomate by the atmosphere via transpiration. Atmosphere has very low water potential
2) Pulling out of water causes adjacent tissues to lose water swell, creating tension in the xylem
3) Water sticks together via hydrogen bonds
4) Pressure is lowest (most negative) at the top of plant. Water moves up the plant via pressure gradient from high to low

Question 12

summary tree pic

Answer 12

1) Water moves from root, shoot, to leaf. by xylem :UPWard only
2) Photosynthesis occurs in leaf. Co2 goes in, O2 produced
3) Sugars are also being made. Sugars move down plant via phloem to roots and other tissues. phloem flow is all directions
4) Roots respirate, take in oxygen

Question 13

3 cell compartments

Answer 13

1) Cytoplasm: all material in cell
2) Cytosol: all material in cell except organelles
3) Vacuole cell wall

Question 14

Transport routes

Answer 14

1) Symplastic: inside cell membrane
2) Apoplastic: outside cell membrane inside cell wall (hydrophilic)
3) Transmembrane: inside and outside cell membrane

Question 15

Water potential energy

Answer 15

• Psi
  -Mpa and atm
  1Mpa = 10 atm/bars
  Water potential energy = pressure potential + osmotic/solute potential

Question 16

Pressure potential

Answer 16

can be negative, 0, or positive
add Positive pressure: water moves away FROM that area
add negative pressure: water moves toward that area

Question 17

Osmotic/solute potential

Answer 17

can be 0 or positive
add solute, decrease osmotic potential, water flows in that area
take away solute, increase solute potential, water flows out of that area

Question 18

positive pressure and osmotic pressure

Answer 18

cancel out sometimes

Question 19

sap

Answer 19

mineral water, xylem moves sap upward only

Question 20

herbaceous

Answer 20

means non woody

Question 21

apoplast

Answer 21

non living continuum outside cytosol

includes cell wall, xylem cells (tracheas and vessel elements) and extracellular spaces

Question 22

symplast

Answer 22

continuum of cytosol connected by plasmodesmata

Question 23

Root pathway of fluid (xylem)

Answer 23

1) Water enters root hair
2) either takes symplastic pathway: inside cell membrane or the apoplastic pathway: outside the cell membrane
3) Reaches the endodermis, hits the casparian strips: waterproof and impermeable to ions
4) casparian strip inhibits passage into the endordermis if taking apoplectic pathway. Forces fluid to go inside the cell membrane of endodermis.
5) Endodermis to xylem

Question 24

stele

Answer 24

• all material inside endodermis
• xylem and phloem
• contains pericycle
• pith