Lecture 5 -- Plants

Question 1

what does secondary growth occur in

Answer 1

only in conifers and woody eudicots, no monocots are woody.

Question 2

what does secondary growth produce

Answer 2

wood and bark

Question 3

what does primary growth occur in

Answer 3

all vascular plants: ferns and seed plants

Question 4

how does secondary growth originate: what causes it

Answer 4

ring around separation of primary xylem and phloem, this is called the vascular cambium

Question 5

secondary xylem what is it made by, location, what it is

Answer 5

made by vascular cambium, to the inside of it, and is the wood in conifers and woody eudicots

Question 6

secondary phloem, made by what, location, function

Answer 6

made by vascular cambium, located on the outside of the vascular cambium, and takes over the transport of sugar

Question 7

cork cambium, role and location

Answer 7

forms outside of the secondary phloem, it protects plant – adds secondary dermal tissue – new protective layer called periderm which is known as the bark.

Question 8

vascular cambium, primary function

Answer 8

makes secondary xylem and phloem, an produces rays.

Question 9

amount of xylem produced vs phloem

Answer 9

more xylem is produced, – plant gets bigger in diameter by adding more xylem

Question 10

rays

Answer 10

parenchyma, transports minerals in and out of diameter

Question 11

fusiform initials

Answer 11

cells in vascular cambium – tracheids and vessels (xylem) sleeve elements (phloem)

Question 12

ray initials

Answer 12

rays in both xylem and phloem

Question 13

WOOD

Answer 13

secondary xylem lignin in secondary walls of tracheids and vessel elements

Question 14

heartwood

Answer 14

dark xylem, aged wood, less punctual, and dark to help prevent rotting

Question 15

sapwood

Answer 15

younger xylem, lighter in colour

Question 16

growth rings

Answer 16

annual rings of xylem, live in environments with different seasons, exists because of difference in diameter of cells produced in secondary xylem at different times of the year.

Question 17

label 3 year old woods stem.

Answer 17

3 rings of xylem, 1 ring of phloem, and 1 ring of cork. the line between the last ring of xylem and ring of phloem is the vascular cambium, the line between the phloem and the cork is the cork cambium. within the xylem rings, cells are often bigger at start of ring and start to get smaller towards end of ring

Question 18

periderm in 3 layers

Answer 18

phelloderm (inside the cork itself), cork to outside, and cork cambium – these protect woody plants

Question 19

anatomy of trunk

Answer 19

small circle, medium circle, and large circle, within each other. smallest – inside it is the xylem/wood,
medium – inside that is the phloem,
big – inside that is the cork.
line between small and medium is the vascular cambium
line between medium and big is cork cambium

Question 20

cork + cork cambium from tree trunk =

Answer 20

periderm / bark

Question 21

tissues of woody stem time table/ steps
apical meristem, primary meristem, primary tissues, lateral meristem, secondary tissues

Answer 21

apical meristem: protoderm, pro cambium, ground meristem (these are the primary meristems)
protoderm – epidermis
pro cambium – primary xylem and phloem
ground meristem – ground tissue (pith and cortex) (these are the primary tissues)
line between primary xylem and phloem – vascular cambium
context – cork cambium (these two are the lateral meristems)
vascular cambium – rays and secondary xylem + phloem, cork cambium – cork (both cork C and cork form periderm) (these are the secondary tissues)

Question 22

transport: laws

Answer 22

movement of fluid in plants follow 2nd law of thermodynamics. – spontaneous

Question 23

examples of transport

Answer 23

osmosis, diffusion, differences in pressure.

Question 24

Water flows from what to what

Answer 24

more watery areas to less watery places

Question 25

energy naturally tends to do what

Answer 25

spread out rather than stay concentrated in one place

Question 26

disorder of water always goes what direction

Answer 26

up

Question 27

sample overview of water flow

Answer 27

enters through roots, moves up the stem, and out the leaves

Question 28

loss of water from leaves is what

Answer 28

transpiration

Question 29

water enters the plant and moves along plant in three different routes, what are they

Answer 29

apoplastic, symplastic, and transmembrane route.

Question 30

apoplastic

Answer 30

within cell walls, in between both cell walls and membrane.

Question 31

symplastic

Answer 31

fluids move through the plasmodesmata

Question 32

transmembrane

Answer 32

a mixture of both routes

Question 33

cell compartments with three routes

Answer 33

draw three cells and each route.

Question 34

cellulose is highly attractive to what

Answer 34

water -- it is hydrophilic and absorbent

Question 35

process of water movement follows what

Answer 35

process of water potential energy,

Question 36

potential refers to :

Answer 36

as waters capacity to perform work

Question 37

water flow relative to water potential

Answer 37

flows from regions with higher water potential (less negative) to lower water potential (more negative) totally water potential = potential of solutes + potential of pressure

Question 38

water potential of a region wit solutes

Answer 38

water potential of a region with solutes is lower than a region without solutes

Question 39

draw the 4 pictures representing water potentials with the two components solute and pressure

Answer 39

one with just solute, water should be flowing right, one with positive pressure water should flow left, one with both, water is at equilibrium, and last one with negative pressure, water is flowing right

Question 40

what does the term plasmolysis mean

Answer 40

loss of water from cell by osmosis. cell membrane separates from cell wall

Question 41

initial flaccid cell with solute potential of -0.7 what happens if put in sugar solution? in pure water?

Answer 41

sugar solution: the solute potential of sugar solution is -0.9 therefore has LESS potential that cell, that means that water will flow OUT of cell to lower potential. -- cell shrinks pue water: pure water has potential of 0, so -0.7 is LESS than pure water. therefore because of higher potential in water than in cell, water will flow INTO cell, enlarging it, the cell membrane is now pushing against cell wall -- turgid (swollen due to pressure)

Question 42

water moves spontaneously from higher to Lower water potential true or false

Answer 42

true

Question 43

what way to water and minerals travel

Answer 43

upward ; tracheids in all vascular plants, and vessels in flowering

Question 44

where does the ascent of sap occur

Answer 44

in xylem

Question 45

what does herbaceous mean

Answer 45

non woods mature eudicot, root

Question 46

water enters what

Answer 46

root, lateral transport of H2O and mineral;s

Question 47

what two roots does water transport by

Answer 47

apoplectic and symplastic

Question 48

steps of water flow

Answer 48

water flows into root hair, because water potential is less inside the root hair than outside. - then the water travels toward the stele, and encounters the special layer (endodermis) - the endodermis has wax in its cell wall;s called Suberin. - this Suberin makes casparian strips which is a barrier preventing molecules from passing - the water will get stopped by the casparian strip if flowing though the apoplectic route. - it gets shunted around therefore has to go through the cell membrane to get into the vascular tissues - the cell membrane controls the amount of water and minerals;s that enters the cell

Question 49

what are plant roots associated with

Answer 49

fungus -- mycorrihizahe

Question 50

what does mycorrhizae mean

Answer 50

"myco" = fungus " rrhizae " = roots

Question 51

what does mycorrhizae do

Answer 51

increases surface area and aids absorption of minerals

Question 52

benefits for both fungus and plants

Answer 52

fungus: gets photosynthetic products esp. sugar plants: gets increase of ions -- uptake in minerals

Question 53

pathway of water simplified

Answer 53

1. enters through soil 2. goes through root hair, or mycorrhizae1 3. to cortex 4. through endodermis 5. to xylem 6. into atmosphere. this happens naturally. -- IS PASSIVE

Question 54

how do water and minerals MOVE UP A PLANT

Answer 54

transpiration-cohesion-tension mechanism

Question 55

transpirational pull

Answer 55

in leaves there is a pull of water, as water leaves the plant through an opening in the leaf (stomate) this pulls water up through the plant (like a rope)

Question 56

why is water being pulled up through the plant

Answer 56

because water is being lost by the leaf

Question 57

water flow in xylem step by step (transpiration-cohesion-tension mechanism)

Answer 57

1. water evaporates from moist cells in. leaf stomates -- transpiration (because atmosphere has low water potential therefore high --> low) 2. water potential is lowered at air-water interface, causing negative pressure (tension) in xylem. -- hydrogen bonds hold water molecules together, (cohesion) -- xylem is UNDER TENSION GRADIENT so negative pressure at the top, and positive pressure at the bottom, therefore water will flow from bottom to up. THIS IS A PASSIVE PROCESS

Question 58

control of transpiration by stomates: cues to open at dawn:

Answer 58

light, CO2 depletion, and circadian rhythm -- when filled with fluid they open, water / gasses can flow in and out

Question 59

dry conditions; stomates

Answer 59

closure (to prevent water loss) abscisic acid is a hormone that causes K+ to leave guard cells and that stimulates the closure.

Question 60

somtate = what

Answer 60

2 guard cells

Question 61

states of guard cells -- open and closed whennn:

Answer 61

open when cells are turgid (swollen bc of + pressure) closed when cells are flaccid -- lost + pressure