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© 2014 Pearson Education, Inc.
EudicotsMonocots
Stems
Embryos
Roots
One cotyledon Two cotyledons
Leafvenation
Veins usually parallelVeins
usually netlike
Vascular tissuescattered
Vascular tissueusually arranged in ring
Root system usually fibrous (no main root)
Taproot (main root) usually present
PollenPollen grain with
one openingPollen grain withthree openings
Flowers
Floral organs usuallyin multiples of three
Floral organs usually in multiples of four or five
1
© 2014 Pearson Education, Inc.
Apical bud
Shootsystem
Apical bud
TaprootStem
Reproductive shoot (flower)
InternodeNode
Vegetative shoot
BladePetiole
Leaf
Axillary bud
Rootsystem
Lateral(branch)roots
2
© 2014 Pearson Education, Inc.
Spines Tendrils
StemStorage leaves
Storage leavesReproductive leaves
6
© 2014 Pearson Education, Inc.
Fiber cells (cross section from ash tree) (LM)
25 m
Cell wall
Sclereid cells (in pear) (LM)
5 m
10
© 2014 Pearson Education, Inc.
Tracheids and vessels (colorized SEM)
100 mVessel Tracheids
Vessel elements, with perforated end walls
Vessel element
Perforationplate
Pits
Tracheids11
© 2014 Pearson Education, Inc.
Sieve-tube element (left)and companion cell:cross section (TEM)
30 m
Sieve plate
Plasmodesma
Sieve-tubeelements
Companioncells
Sieveplate
Sieve plate with pores (LM)
15 m
Sieve-tube elements: longitudinal view (LM)
Nucleus ofcompanioncell
Sieve-tube elements: longitudinal view
3 m
12
© 2014 Pearson Education, Inc.
Shoot tip(shoot apicalmeristem andyoung leaves)
Axillary budmeristem
Root apicalmeristems
Primaryxylem
Cork cambium
Vascular cambium Lateralmeristems
Secondaryxylem
Primaryphloem
Secondaryphloem
Cork cambium
Vascularcambium
Pith
Periderm
Cortex
Primaryxylem
Primaryphloem
Pith
Cortex
Epidermis
Secondary growth in stems
Primary growth in stems
13
© 2014 Pearson Education, Inc.
Internode
This year’s growth(one year old)
Apical budBud scale
Stem
Node
Axillary buds
Last year’s growth(two years old)
Growth of twoyears ago(three years old)
Bud scar
Leaf scar
Leaf scar
Budscar
Leafscar
One-year-oldbranch formedfrom axillary budnear shoot tip
14
© 2014 Pearson Education, Inc.
Corticalcells
GLABRA-2 isnot expressed,and the cellwill developa root hair.
GLABRA-2 is expressed,and the cell remains hairless.
The root cap cells will be sloughedoff before root hairs emerge.
20
m
15
© 2014 Pearson Education, Inc.
Mitoticcells
Root cap
Zone of celldivision(includingroot apicalmeristem)
100 m
Zone ofelongation
Zone ofdifferentiation
Vascular cylinder
Root hair
Epidermis
Cortex Dermal
VascularGround
16
© 2014 Pearson Education, Inc.
Core ofparenchyma cells
Vascular cylinder
(b) Root with parenchyma in thecenter (typical of monocots)
Epidermis
Cortex
Dermal
Vascular
Ground
70 m
100 m
Endodermis
Pericycle
Xylem
Phloem 100 m
Endodermis
Pericycle
Xylem
Phloem
(a) Root with xylem and phloem inthe center (typical of eudicots)
17
© 2014 Pearson Education, Inc.
Epidermis
Cortex
Pericycle
Lateral root
Vascularcylinder
Emerginglateralroot
100 m
18
© 2014 Pearson Education, Inc.
Shoot apical meristem
Youngleaf
Leaf primordia
Developingvascularstrand
Axillary budmeristems
0.25 mm19
© 2014 Pearson Education, Inc.
Guardcells
Bundle-sheathcell
Sclerenchymafibers
Dermal
VascularGround
(a) Cutaway drawing of leaf tissues
Cuticle
Xylem
Phloem
Stoma
CuticleVein
(c) Cross section of a lilac(Syringa) leaf (LM)
Guard cellsVein Air spaces
(b) Surface view of a spiderwort(Tradescantia) leaf (LM)
Guardcells
Stomatalpore
Epidermalcell
Upperepidermis
Lowerepidermis
Palisademesophyll
Spongymesophyll
10
0
m5
0
m
20
© 2014 Pearson Education, Inc.
Dermal
Vascular
Ground
Groundtissue
Sclerenchyma(fiber cells)
XylemPhloem
Vascular bundles
Epidermis
Cortex
Pith
EpidermisVascular bundle
Ground tissueconnectingpith to cortex
(b) Cross section of stem with scatteredvascular bundles (typical of monocots)
(a) Cross section of stem with vascularbundles forming a ring (typical of eudicots)
1 mm1 mm
21
© 2014 Pearson Education, Inc.
Primaryxylem
Primary phloem
Cortex
Pith
Epidermis
Vascular cambium
(a) Primary and secondary growthin a two-year-old woody stem
Secondaryxylem
Secondary phloem
Growth
Cork
Early wood
Periderm(mainlycorkcambiaand cork)
Primary xylem
Primary phloem
Cortex
Pith
Epidermis
Vascular cambium
Secondaryxylem
Secondary phloem
Vascularray
First cork cambium
Growth
Cork
Layers ofperiderm
Bark
Most recentcork cambium
Secondary xylem
Secondary phloem Vascular
cambium
Corkcambium
Periderm
Vascularray
CorkBark
(b) Cross section of a three-year-old Tilia (linden) stem (LM)
Growthring
Late wood
1.4 mm
1 m
m
22
© 2014 Pearson Education, Inc.
Secondaryxylem
Secondary phloem
Vascular cambium
Growth Vascular cambium
After one yearof growth
After two yearsof growth
23