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Structure of Woody Plants - Coggle Diagram
Structure of Woody Plants
Secondary Phloem
formed from the vascular cambium
consist of only parenchyma cells
axial system
responsible for the conduction up and down the stem or root
contains sieve tubes members and companion cells
Anomalous Forms of Growth
unusual primary growth
the palm trunk is all primary tissue consisting of vascular buddles
establishment growth
increase in width and addition of adventitious roots in palms
anomalous secondary growth
unequal activity of the vascular cambium
all areas of the vascular cambium have about equal activity
in some species, two sectors of cambium is very active while two are almost completely inactive
secondary growth in monocots
none of the monocots have secondary growth like that in gymnospems, basal angiosperms, and eudicots
first two group undergo a process of anomalous secondary growth
included phleom
located between two bands of xylem
in eudicots, vascular cambium arises and produces ordinary secondary xylem and phloem
roots of sweet potatoes
the amount of storage parenchyma is increased by anomalous secondary growth
new vessels are surrounded by new cambium
cambia all functioning simultaneously speed the production of storage capacity
Secondary Growth in Roots
contains bother ray and fusiform initials and wood produced in the root
several mechanisms exist by6 with the storage capacity of a woody root can be increased
root of conifers and woody angiosperms undergo secondary growth and so do stems
Vascular Cambium
fusiform initials
long, tapered cells
produces two elongate cells
ray initials
they undergo periclinal cell divisions
short, and less cuboidal
typically grouped together in short vertical rows only one cell wide, two cell wide, or many cells wide
Initiation of the vascular cambium
is on of the meristems that produce the secondary plant body
forms in leaves that stay on a tree for many year, which is very rare
arrangement of the cambial cells
ray and fusiform initials are organized in specific patterns
vascular cambium forms as a narrow cylinder
Secondary Xylem
heartwood and sapwood
Heartwood
the dense inner part of a tree trunk
sapwood
a new layer of sapwood is formed each year by the vascular cambium
has a more or less constant thickness
reaction wood
cambial cells are oriented other than vertically
growth rings
early wood
wide vessels or in conifers, wide tracheas
produced earlier in the growing season
late wood
summer wood, can have lower proportion of vessels
annual ring
1 year's growth
diffuse porous
produced in the spring and are neither more abundant nor obviously wider than those produced in the summer
growth ring
shows how old the organism is
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types of wood cells
fibers
gives wood strength and flexibility
screreids
produce the gritty texture of guavas.
reduced form of sclerenchyma cells with highly thickened
vessel elements
the water conducting tissue of plants
constitute the major part of the water transporting system
tracheids
a type of water-conducting cell in the xylem which lacks perforations in the cell wall.
serve for support and for upward conduction of water and dissolved minerals
paranchyma
function in storage, photosynthesis, and as the bulk of ground and vascular tissues
most common cell
Outer Bank
lenticels and oxygen diffusion
bark becomes permeable to oxygen when cork cambium produces cork cells
because rounded cells can not fit tighly together, it creates a diffusion pathway for oxygen
lenticels contain more layers of cells and protrude outward
initiation of cork cambia
timing of initiaion is more variable than that of vascular cambium
stems
surface color changes from green to tan
other species
cork cambium arises before twig or root is even 1 year old
form only when that region is several years old
cork and the cork cambium
cork cambium
tissue in the stem of a plant that gives rise to cork on its outer surface
cork cell
cell walls made up of a waxy substance called suberin
They prevent the loss of water by evaporation and transpiration.
inner bark
all secondary phloem between the vascular cambium and the innermost cork cambium
outer bark
all tissue outside the innermost cork cambium comprise
prevents the tree from losing moisture when the air is dry.
