Ch 35/36 Stem/ Root

Question 0

7 outer stem structures Herbaceous and function/what it is

Answer 0

1. Bud - undeveloped embryonic shoots
2. Terminal Bud - at tip of stem
3. Axillary bud(lateral) - located in leaf axils
4. Node - area where leaf is attached
5. Internode - region between 2 nodes
6. Stomata - present on Herbaceous stems for gas exchange
7. Epidermis - on Herbaceous stems for protection as with leaves

Question 1

3 stem functions

Answer 1

1. Growth: produce new tissue
2. Support: holds structures above-ground
3. Transport: connect roots with tips of shoot system

Question 2

5 Woody stem structures different than herbaceous

Answer 2

1. Bud Scales - cover/protect dormant buds
2. Bud Scale Scar - left where bud scale falls off when bud resumes growth
3. Leaf Scar - where leaf was attached to stem
4. Lenticels - sites of loosely arranged cells that allow Oxygen to diffuse into interior of Woody stem
5. Periderm (outer bark) - replacement for epidermis on Woody stems

Question 3

2 Internal stem structure arrangement: Herbaceous Eudicot

Answer 3

• vascular bundles arranged in circle

- distinct Cortex and Pith (primarily for storage)

Question 4

3 Internal structure arrangement of Monocot (All Herbaceous) Stems

Answer 4

• Vascular bundles scattered in ground tissue
• NO distinct cortex/pith
• Primary Growth ONLY

Question 5

In a Eudicot, what are the 2 major types of ground tissue in a Leaf?

Answer 5

Palisade

Spongy mesophyll

Question 6

What is secondary growth, where/what type(mono/dicot/gymno/angiosperm) does it occur?

Answer 6

production of secondary tissues(wood/bark) through lateral meristems
- occurs in “Dicots” and Gymnosperms

Question 7

2 areas of secondary growth and what do they produce

Answer 7

1. Vascular Cambium: produces Secondary Xylem(wood) /Phloem(inner bark)
2. Cork Cambium: produces periderm

Question 8

Cork Cambium produces Periderm which includes what the outer bark which is______ and ______. what’s their use?

Answer 8

outer bark

1. Cork Cells - replace epidermis in Woody
2. Cork Parenchyma - storage

Question 9

Xylem/ Phloem growth patterns in spring and summer. How might it be different in tropics or during drought?

Answer 9

Xylem
Spring: following dormancy, Large cells with Thin walls form for increase Water uptake
Summer: Small cells with Thick walls form for greater Strength

Phloem: crushed each year and Added to Bark

Question 10

• what type of trees are associated with Hardwood and Soft wood
• what are 2 types of wood in a tree

Answer 10

Softwood: wood of Conifers - Lacks Vessel elements and fibers
Hardwood: wood of Angiosperms (not always literally hard)

Heartwood: in middle(heart) - as trunk’s girth increases, oldest xylem is filled with waste products(increase strength/pest resistance)
Sapwood: outer area. Functional Xylem

Question 11

Xylem Transport(what it does in which direction and from where)

Answer 11

Water and dissolved minerals move upward from soil to root to stem to atmosphere

Question 12

Phloem Transport(what it does in which direction and from where)

Answer 12

Sugar from leaves(made by photosynth.)

movement up and down and require energy from the plant

Question 13

what is the most direct source of energy for xylem transport under normal conditions?

Answer 13

Sunlight

Question 14

what hypothesis explains movement of materials in phloem

Answer 14

Pressure-Flow Hypothesis

Question 15

What is Water Potential (W.P.)

Answer 15

a measure of tendency for osmosis to occur

i.e. measure of a cell’s ability to release/absorb water

Question 16

how does water move and when will Osmosis occur (both considering W.P.)

Answer 16

water moves from regions of Higher W.P. to regions of Lower

- Osmosis will occur when W.P.s are Unequal

Question 17

What 2 forces cause Xylem’s upward flow? Which is stronger?

Answer 17

pull of Transpiration(stronger) and Root Pressure

Question 18

Why does Root Pressure occur

Answer 18

water moves into roots due to active absorption of mineral ions from soil

Question 19

When might Guttation occur?

Answer 19

when soil is wet, and the difference in root and soil W.P. is great enough

Question 20

What is the Predominant Sugar translocated in Phloem?

Answer 20

Sucrose

Question 21

Describe phloem translocation of sugar. Is it faster or slower than Xylem trasnport?

Answer 21

dissolved sugar is moved up or down from a Leaf (source of excess sugar)
- to a Sink (area of storage or sugar use: Roots, apical meristems, fruits, seeds)

• Slower than xylem transport

Question 22

In the Pressure-Flow Hypothesis, how is turgor pressure produced?

Answer 22

by water entering phloem at a source and leaving at a sink drives flow(in phloem)

Question 23

which type of specialized stem is underground with fleshy leaves attached to a short stem?

Answer 23

Bulb

Question 24

which type of specialized stem is a Horizontal underground stem

Answer 24

Rhizome

Question 25

which type of specialized stem is a fleshy underground stem enlarged for food storage

Answer 25

Tuber

Question 26

which type of specialized stem is short, erect, and underground covered by papery scales

Answer 26

Corm

Question 27

which type of specialized stem is horizontal Above ground

Answer 27

Stolon

Question 28

at the core of an Herbaceous Eudicot Stem is...

Answer 28

Pith

Question 29

What is the Radical in a Taproot System?

Answer 29

embryonic root of a seed plant

Question 30

what is a Taproot System? | common in monocots or eudicots?

Answer 30

has one main root formed from the radicle from which lateral root extend common in eudicots

Question 31

How is a Fibrous Root System primary in monocots or eudicots?

Answer 31

has many Adventitious roots of same size developed from stems. Lateral roots branch from adventitious roots primary in Monocots

Question 32

Roots: Eudicots | 3 primary tissues inside and what type of growth

Answer 32

- Epidermis - Cortex (ground tissues) - Stele (vascular tissues)

Question 33

What is the Epidermis used for, what does it allow?

Answer 33

for protection but no cuticle allowing water absorption

Question 34

Root hairs' functions, where are they located

Answer 34

short-lived extensions of epidermal cells | - help absorb water and dissolved minerals

Question 35

what happens that causes clay to be attracted to roots

Answer 35

roots secrete H+ (cations) which displace other positively charged mineral ions from soil particles, clay has negative charges on the outer surface

Question 36

Eudicot Roots - What is the Cortex mostly made of - What is the innermost layer of the cortex called and what does it do?

Answer 36

mostly parenchyma cells(store starch) | - Endodermis: regulates movement of water/minerals into root xylem

Question 37

Which of the 2 pathways of water/minerals through the epidermis and cortex... - goes along interconnected cell walls, outside of cell membranes until reaches endodermis - goes through cell's interconnect cytoplasm and plasmodesmata, inside cells

Answer 37

- Apoplast | - Symplast

Question 38

Stele (Vascular cylinder) | What gives rise to lateral roots and meristems

Answer 38

Pericycle

Question 39

how is xylem and phloem in the root of eudicots

Answer 39

xylem forms solid core in the center (NO PITH) | looks like X

Question 40

how is xylem and phloem in the Root of a Monocot | - what type of growth

Answer 40

alternate rings of xylem and phloem bundles surround center of PITH - NO vascular cambium - PRIMRY GROWTH, no secondary growth