Please enable JavaScript.
Coggle requires JavaScript to display documents.
Structure of Woody Plants , reaction wood , tylosis , Cork_cambium_2 ,…
Structure of Woody Plants
Concepts
primary tissues
epidermis, cortex, vascular bundles, pith and leaves
make up primary plant body
woody species
vascular cambium
#
cork cambium
secondary tissues
primary tissues
wood and bark
conducting tissues
secondary growth
live longer
takes more energy
older stems and roots
Vascular Cambium
Initiation of the Vascular Cambium
vascular cambium
produce secondary plant body
must be extended each year
contains segments of distinct ages
never in flowers, fruits, or seeds
two types of cells fusiform initials and ray initials
fascicular cambium
divide instead of maturing
interfascicular cambium
connects on each side of fascicular cambium
Fusiform Initials
long, tapered cells
periclinal wall
produce two elongate cells
cambium cells
longitudinally divide by anticlinal walls
have thin primary walls
proplastids
Ray Initials
similar to fusiform initials
short and more or less cuboidal
undergo periclinal cell divisions
produce short cells
storage parenchyma
Arrangement of Cambial Cells
Ray initials
grouped together in short vertical rows
biseriate
multiseriate
uniseriate
Fusiform initials
regular horizontal rows
storied cambium
few advanced eudicot species
no horizontal rows
nonstoried cambium
Secondary Xylem
Types of wood cells
secondary xylem
wood
tracheids
vessel elements, fibers, sclereids, and parenchyma
axial system
fusiform initials
pine wood
contains only tracheids
conifers
radial system
#
ray initials
xylem simple
rays
store carbs
procumbent cells
no direct connection with axial cells
upright cells
direct connection with axial cells
ray tracheids
horizontal rectangular cells
hardwoods
softwoods
Growth Rings
early wood
spring wood
late wood
summer wood
early ring
growth ring
not always true annual rings
diffuse porous
vessels throughout it
ring porous
early wood
Heartwood and Sapwood
heartwood
dark wood
heartwood becomes wider with age
sapwood
lighter, moister outer region
new layer formed each year
constant thickness
tylosis
a plug
Reaction Wood
gravity causes lateral stress
fibers extent tension on the branch
Secondary Phloem
formed from the vascular cambium
#
axial system
conduction up and down stem or root
contains sieve tube members and companion cells
radial system
Outer Bark
Cork and the Cork Cambium
cork cambium
phellogen
cells are cuboidal
outer cells
cork cell
phellem cell
phelloderm
periderm
outside innermost cork cambium
outer bark
innermost cork cambium
inner bark
Lenticels and Oxygen Diffusion
cork
keeps out pathogens and retains water
blocks absorption of oxygen
bark
becomes permeable to oxygen
aerenchymatous cork
lenticels
contain more layers of cells and protrude outward
Initiation of Cork Cambia
sometimes before a year old
surface color changes green to tan
bark dramatically different from bark it will have when older
Secondary Growth in Roots
root vascular cambium
contains both ray and fusiform initials
perennial roots also form bark
Anomalous Forms of growth
Anomalous Secondary Growth
alternative cambia produce secondary bodies that differ from the common type
Roots of Sweet Potatoes
storage parenchyma is increased by anomalous method of secondary growth
hundreds of cambia of various ages
Included Phloem
vascular cambium arises and produces secondary xylem and phloem
type of secondary phloem, located between two bands of xylem
Unequal Activity of the Vascular Cambium
two sectors of the cambium very active
growth is adaptive
Secondary Growth in Monocots
no secondary growth like in gymnosperms
secondary vascular bundles
Unusual Primary Growth
palm trees
trunks do not taper
establishment growth
form of primary growth
Vascular cambium is a woody species
Radial system has secondary phloem
Vascular Cambium is formed from secondary phloem