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Ch:9 Structure of woody of plants - Coggle Diagram
Ch:9 Structure of woody of plants
Primary plant body.
cortex, vascular bundles, pith, epidermis, leaves
Secondary tissues
cork cambium, secondary xylem, bark
For Ex: sycamores, roses etc.
Vascular cambium
Fusiform initials
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vascular cambium divides longitudinally ny anticlinal walls.
700-8700 micrometer in conifers
140-162 micrometers long in dicot
long, tapered cells
produces tracheas, vessels elements and fibers
interfasicular cambium
resume mitosis
Fasicular cambium
produce secondary plant body.
Ray initials
short and more or less cuboidal
produce parenchymal and albuminous cells.
Arrangement of Cambial Cells
ray initials are grouped together
uniseriate
Fusiform Initials occurs in
Storied cambium
For Ex: redbud, permission
non storied cambium
Secondary Xylem
Types of Wood Cells
vascular cambium developed into secondary xylem is wood
axial system derived from fusiform initials
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radial system derived from ray initials.
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hard wood- wood of all basal angiosperms and edicts
soft woods- few or no fibers and have softer consistency
Foe EX: pines, redwoods, bald-cypress are soft woods
Growth Rings
late wood
can have low proportion of vessels
first wood formed is early wood
must have high proportion os wide vessels
Alternative arrangement
ring porous
vessels restricted to early woods
For Ex: red oak, sassafras, honey locust
Diffuse porous
growth ring has vessels throughout it.
For Ex: yellow birch, aspen, sugar maple
Annual rings
early wood + late wood
Heart Wood and Sap Wood
Heart wood
dark and dry central wood
Sap Wood
lighter and moisture wood
Reaction wood
branch developed in counteraction of gravity
also known as tension wood
mostly found in upper side of tree
Outer bark
Cork and Cork Cambium
cork cambium is also known as phellogen
after division, out cell becomes cork cell and inner cells become cork cambium.
cuboidal cells
tissues outside innermost cell is outer bark
inner bark is secondary phloem between vascular cambium and innermost cork cambium
Secondary Phloem
formed from vascular cambium
axial and radial system present
size, shape and number of phloem rays is same as that of xylem
Lenticels ansd Oxygen Diffusion
area of aerenchymatous cork
pathway for diffusion
more active, more cells and protrude outwards.
Initial of Cork Cambia
timing of initiation is not constant
on stems, it is detectable
for cacti, the formation is delayed.
fiber cells produce fibrous, stringy bark
sclereid- filled phloem produces hard bark.
Secondary Growth in Roots
Conifers and woody angiosperms undergo secondary growth
contains both ray and fusiform initials
woods of roots does not resemble shoots
conductivity also differs in roots and shoots
storage capacity can be increased in roots
Anamalous forms of Growth
Anamolous Secondary Growth
growth of secondary bodies from alternative cambia
Roots of Sweet potatoes
amount of storage is increased
large vascular cambia increases the storage capacity
xylem and phloem are parenchymal
Included Phloem
located between two bands of xylem
protection of phloem from insects and pests
Unequal Activity of the vascular cambium
in
Bauhinia
, two sections of vascular cambium is active.
conduction capacity is high
flexibility is low
secondary growth in Monocots
Jousha tree and dragon trees are woody.
no conducting cells
secondary vascular bundles with xylem and phloem
Unusaual Primary Growth
plam trees trunk are not tapered.
seedling do not have full set of leaves.
Establishment Growth
adventitious roots are established
same rate of conduction throughout the life
