Chapter 8: Structure of Woody Plants
outer bark
cork and cork cambium
cork cambium
produced into mature parenchyma layer
phelloderm
also called phellogen
cuboidal cells
outer bark
all tissue outside of he innermost cork cambium
inner bark
secondary phloem between vascular cambium and innermost cork cambium
vascular cambium
initiation of the vascular cambium
arrangement of cambial cells
organized in a specific pattern
ray initials
grouped together in short vertical rows
fusiform initials
regular horizontal growth
vascular cambium
meristem that produce secondary plant body
monocots
absent in all species
some have anomalous secondary growth
euidots
present in many species
many are herbs
gymnosperms
present in all species
basal angiosperms
present in many species
many are herbs
two types of cells
fusiform initials
long tapered cells
ray initials
short, less cuboidal cells
interfascicular cambium
between vascular bundles
resume mitosis
some mature parenchyma cells
fascicular cambium
cells continue to divide rather than maturing
secondary phloem
formed from vascular cambium
has axial and radial system
axial system
responsible for vertical conduction
radial system
responsible for horizontal conduction
secondary xylem
growth rings
annual rings
growth ring
1 ring=1 year
tells age of tree
types of wood cells
radial system
derived from ray initials
parenchyma and tracheids are present
axial system
hardwoods
lacks fibers
derived from fusiform initials
angiosperm woods contain
large amounts of fibers
contains tracheas and/or vessel elements
contain
parenchyma
fibers
tracheids
vessel elements
sclerids
anomalous forms of growth
unequal activity of the vascular cambium
ordinary growth
all areas have equal activity
secondary growth in monocots
secondary vascular bundles
parenchyma cells undergo rapid cell division and produce narrow cells
include phloem
several eudicots
vascular cambium arises
produces ordinary secondary phloem and xylem