Chapter 8: Structure of Woody Plants
Initiation
Provascular Tissue
Fascicular
Vascular Cambium
Secondary Xylem
Outer Bark
Types of Wood Cells
Growth Rings
Heartwood & Sapwood
Reaction Wood
Secondary Phloem #
Cork and the Cork Cambium
Lenticels and Oxygen Diffusion
Initiation
Secondary Growth in Roots
Anomalous Forms of Growth
Anomalous Secondary
Roots of Sweet Potatoes
Included Phloem
Unequal Activity of the Vascular Cambium
Secondary growth in Monocots
Unusual Primary Growth
produces secondary plant body
Cells
Arrangement of Cambial Cells
Ray initials
Pith
Fusiform Initials
Interfascicular
axial xylem
axial phloem
Phloem Rays
Xylem Rays
long, tapered cells
short and cuboidal
fusiform
regular horizontal rows
ray
short vertical rows
storied
irregular no pattern
nonstoried
periclinal wall
anticlinal wall
parallel
perpendicular
wood
axial system
radial system
fusiform
ray
tracheary elements
longitudinal conduction
parenchyma
hardwoods
fibers-stronger
softwoods
less fibers-softer
ray cells
upright
procumbent
ray tracheids
horizontal rectangular cells
secondary walls
circular bordered pits
quiescence
stress, winter, drought
no cell division
annual ring-1 year growth
early wood
late wood
spring wood
summer wood
high vessel count
less vessels
first wood
diffuse porous
ring porous
vessels form constantly
vessels restricted to early wood
indistinct
Heartwood
Sapwood
center
dark, dry
outer
lighter, moister
new layer formed by vascular cambium every year
one annual ring converted to heartwood each year
become indistinguishable and join together to make vascular cambium
tension wood
angiosperms
upper side of branch=wider
gravity
eccentric
compression wood
conifers
rich in cellulose
little lignin
underside =wider
less cellulose
more lignin
formed from vascular cambium
axial and radial system
no arrangement
only innermost layer of phloem capable of conduction
phellogen
cells =cuboidal
cell division
inner cell =remains cork cambium
outer cell =cork cell
periderm
maturation
protection
short lived
new cork
tissues outside inner cork cambium
inner bark
all secondary phloem between vascular cambium and innermost cork cambium
keeps out pathogens
maintain water
Blocks absorption of oxygen