Ch. 6 Tissues and the Primary Growth of Stems
Concepts
Basic Types of Cells and Tissues
External Organization of Stems
Internal Organization of Stems: Arrangement of Primary Tissues
Stem Growth and Differentiation
Parenchyma
Sclerenchyma
Collenchyma
Epidermis
Cortex
Vascular Tissues
Xylem
Phloem
Vascular Bundles
herb
consists
of
leaves
stems
roots
first
land
plants
algae
no
stems
leaves #
roots
mutation
growing
upright
selective advantage
absorptive cells
can't
photosynthesize
shaded
water
transported
supportive
tissues
modern
stems
produce
leaves
hold
in
sunlight
store
sugars
other nutrients
angiosperm #
largest
division
in
plant
kingdom
279,000
species
diversified
monocots
eudicots
basil angiosperm
laurels
waterlilies
magnolias
broadleaf
maples
asters
roses
grasses
lilies
cattails
poms
phylodendrons
bromeliads
herbacious body
woody body
secondary
plant body
primary
plant body
plant
that
never
becomes
woody
lives
less
than
a
year
snapdragons
petunias
corn
wheat
beans
for
years
irises
lilies
trees
and
shrubs
boxwood
rose
magnolias
oaks
maples
only
primary
walls
that
remain
thin
tissue
mass
of
parenchyma cells
most
common
cell
tissue
constituting
all
soft
parts
examples
soft leaves
petals
seeds
fruits
active
metabolically
remain
alive
after
maturing
chlorenchyma
parenchyma cells
involved
in
photosynthesis
numerous
chloroplasts
thin walls
allow
light
co2
to
pass
through
glandular cells
secrete
nectar
fragrances
mucilage
oils
resin
contain
few
chloroplast
elevated
dictyosomes
ER
transport
large
amounts
into themselves
sugar
minerals
transform
and
out
them
out
transfer cells
mediate
short
distance
transport
material
by means
of a
large
extensive
plasma
membrane
capable
of
holding
numerous
molecular pumps
primary wall
remains
thin
in some
areas
thick
most
often
in
corners
exhibits
plasticity
like
clay
present
elongating
shoot
tips
must be
long
flexible
layer
under
epidermis
as
bands
located
next to
vascular
bundles
has
primary wall
thick
secondary wall
lignified
elastic
develop
from
parenchyma cells
deformed
by
wind
animals
snow
supports
plants
just
by
strength
two types
conducting
mechanical
subdivided
fibers
sclereids
short
isodiametric
examples
cherry pits
coconut shells
walnut shells
stems
shoots
axis
stem
plus
any
leaves
flowers
buds
have
nodes
where
leaves
are
attaches
internodes
region
between
nodes
leaf axil
stem
area
just above
where
leaf
attaches
axillary bud
minature
shoot
with
apical
dormant
several
young leaves
meristem
bud scales
small
corky
waxy
modify
leaves
protect
delicate
organs
terminal bud
at
extreme
tip
each
stem
phyllotaxy #
arrangement
leaves
on
stem
bulbs
short
shoots
have
thick
leaves
fleshy
examples
onions
daffodils
garlic
corms
vertical
thick
stems
have
thin
papery
leaves
exmaples
crocus
gladiolus
rhizomes
fleshy
horizontal
stems
allow
plant
to
spread
underground
tubers
horizontal
grow
only
short
periods
of time
underground
plant
organ
trunk
vertical
main
shoot
outermost
surface
of
herbaceous
stem
single
level
parenchyma
barrier
against
invasion
shields
internal
delicate
cells
cutin
fat
substance
makes
walls
inpermeable
to
water
cuticle
pure
layer
of
cuten
provides
defense
against
pathogens
guard cells
stomatal pore
together
constitute
stoma
trichomes
epidermal
cells
hairs
shade
tissues
hundreds
sizes
shapes
unicellular
interior
to
epidermis
homogenous
composed of
photosynthetic
parenchyma
collenchyma
sometimes
conducts
water
minerals
distributes
sugars
minerals
vessel tissues
xylem
phloem
tracheids
tracheary elements
annular thickenings
helical thickening
set
of
rings
small
amount
of
secondary wall
pattern
secondary wall
deposition
scalariform thickening
provides
much
more
strength
reticulate thickening
secondary wall
deposited
shape
of
net
circular boredered pits
are
in
most
derived
strongest
tracheary elements
pit membrane
set
of
primary walls
vessel
stack
of
vessel
elements
conducting cells
sieve cells
sieve tube members
sieve elements
differentiate
sieve pores
group
together
sieve areas
sieve tube
seive plates
albuminous cells
controlled
by
companion cells
xylem
and
phloem
together
arrange
one ring
surrounding
pith
region
of
parnchyma
similar
to
cortex
collateral
contains
phloem
xylem
running
parallel
primary xylem
apical meristem
region
at
tip
of
shoot
subapical meristem
just
below
apical meristem
differentiation
begins
proxylem
first
xylem
to
appear
metxylem
largest
tracheary elements
protophloem
exterior
cells
mature
metaphloem
cells
closest
to
metaxlem
protoderm
epidermal cells
in
early
stages
of
differentitation
provascular tissues
young cells
of
xylem
phloem
produce
primary tissues
primary growth
tissue formation
Cross Connection: In the buds of pistachio, leaves are modified into bud scales. Bud scales are protective and waterproof, but they are shed when the bud begins to grow in the spring.
Cross Connection: Irises have distichous phyllotaxy where there is one leaf per node, arranged in just two rows. Iris leaves are flattened from side to side, not top to bottom.
Cross Connection: A fern (Astrolepis) tracheary element can digest portions of primary wall out of several pits, converting them to crude perforations. In angiosperms, the wall-digesting mechanism is more refined and removes the primary wall more completely.