Ch.9 Structure of Woody Plants
Concepts
Vascular Cambium
initiation of the vascular cambium
fusiform initials
ray initials
arrangement of cambial cells
Secondary Xylem
types of wood cells
growth rings
heartwood and sapwood
reaction wood
Secondary Phloem
Outer Bark
cork and the the cork cambium
lenticels and oxygen diffusion
initiation of cork cambia
Secondary Growth in Roots
Anomalous Forms of Growth
anomalous secondary growth
unusual primary growth
primary tissues
epidermis
cortex
vascular bundles
pith
leaves
together
constitute
primary plant body
secondary tissues
secondary xylem
secondary cork
secondary phloem
secondary body
bark #
contains
conducting
tissues
gives
greater
capacity
to move
water
minerals
upward
carbohydrates
downward
vascular cambium
one
meritstem
produce
secondary
plant
body
fascicular cambium
portion
vascular cambium
develops
in
vascular bundle
interfascicular cambium
deveops
from
parechyma cells
between
vascular bundles
simple
meristem
two
cell
types
fusiform initals
ray initials
long
tapered
cells
undergoes
longitudinal
cell
division
wall
parallel
cambium
circumference
periclinal wall
produce
two
elongated cells
one
continues
as
fusiform initial
other
differentiaties
secondary xylem
phloem
anticlinal walls
perpendicular
to
cambium
surface
increases
number
of
cambial
cells
short
cuboidal
ungergo
peiclinal
cell divisions
one
daughter
remaining
a
cambial
ray initial
other
differentiating
xylem parenchyma
if it
is the
inner cell
phloem parenchyma
if
outer cell
ray initials
grouped
short
rows
vertical
one
cell wide
uniseriate
two
cells wide
biseriate
many
cells wide
multiseriate
fusiform initials
occur
regular
horizontal rows
storied cambium
irregularly
without
horizontal pattern
nonstoried cambium
redbud
persimmon
secondary xylem
all cells
formed
to the
interior
vascular cambium
wood
contains
all
types
of cells
occuring
in
primary xylem
include
tracheids
vessel elements
fibers
parenchyma
sclerieds #
axial system
derived
fusiform initials
radial system
derived
ray initials
hardwoods
contain
large
amounts
fiber
tough
strong
used for
contruction
softwoods
few
or
no
fibers
softer
consistency
rays
can be
uniseriate
biseriate
multiseriate
store
carbs
nutrients
conduct
material
over
short
distances
two types
upright
cells
procumbant
cells
ray tracheids
horizontal
rectangular
have
secondary walls
circular
bordered
pits
protoplasts
early wood
first
wood
formed
high
proportion
wide
vessels
tracheids
late wood
spring wood
summer wood
lower
proportion
vessels
annual ring
one
years
growth
made of
late wood
early wood
growth ring
has
vessels
thorughout
diffuse porous
vessels
restricted
to
early wood
ring porous
examples
yellow birch
aspen
sugar maple
American holly
examples
red oak
sassfras
honey locust
center
of
log
darker
than
outer
wood
drier
more
fragrant
heartwood
dark wood
sapwood
moister
outer
region
tylosis
cytoplasm
plugs
vessel
becomes
wider
with
age
more
or
less
constant
thickness
reaction
to
stress
branch
droops
become
pendant
angiosperms
upper side
tension wood
formed
from
vascular cambium
has
axial
radial
systems
responsible
for
conduction
up
down
stem
or
root
sieve tube members
companion cells
cork cambium
phellogen
cubiodal
inner
outer
remains
cork cambium
turns
into
cork cell
phellem cell
may
produce
cell or two
mature
layer
of
parenchyma
phelloderm
periderm
cork cambium
layers
cork cells
phelloderm
outer bark
tissues
outside
innermost
cork cambum
inner bark
secondary phloem
between
vascular cambium
innermost
cork cambium
cork
consequences
advantageous
negative
blocks
oxygen
absorption
interferes
with
respiration
keeps
out
pathogens
retains
water
lenticels
regions
aerencymatous
cork
with
intercellular
spaces
more
layers
cells
protrude
outwards
timing
of
first
cork cambium
more
variable
than
vascular cambium
roots #
of
conifers
woody
angiosperms
undergo
secondary growth
vascular cambium
contains
both
ray
fusiform
initials
when
alternative
cambia
produce
secondary bodies
that
differ
included phloem
located
between
two bands
of
xylem
secondary growth in monocots
parenchyma cells
undergo
rapid
division
narrow cells
differentiate
establishment growth
increase
in
width
and
addition
of
adventitious
roots
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Cross Connection: Joshua tree is an arborescent monocot in the lily family. Because it has secondary growth, even though of an unusual type, the ability of the trunk to conduct increases, and both branching and increased numbers of leaves are feasible without adventitious roots of the type necessary for screw pine
Cross Connection: Bark of maple peels off in large thin sheets because numerous cork cambia form close together and each is sheetlike.
Cross Connection: The bark of cork oak becomes extremely thick and is composed mostly of phellem, with few sclereids. Cork oaks grown in Spain and Portugal provide most commercial corks used to seal bottles.