13. Xylem or wood
Is a meant to conduct water and mineral salts
upwards from the root to the leaf to give
mechanical strength to the plant body.
Kinds of elements conducting tissues of Xylem
Tracheids
Vessels or tracheae
Wood fibres
Wood parenchyma
16. Tracheids is a elongated,tubes-like cell with
hard,thick,and lignified walls and large cell
cavities.
They are dead,empty cells and their walls are
provided with one or more rows of bordered pits.
It is also annular,spiral,scalariform or pitted (with
simple pits)
Not vessel
17.
18. Vessels or tracheae
Vessels are cylinder, tube-like structure.
Vessels and tracheids form the main elements of
the wood or xylem of the vascular bundle.
They are dead, thick-walled and lignified,and as
such, they also serve the mechanical function of
strengthening the plant body.
19.
20. Xylem(wood) fibers:
Sclerenchymatous cells associated with wood or
xylem are known as wood fibers.
Add to the mechanical strength of the xylem and
of the plant body as a whole.
21.
22. Xylem(wood) parenchyma:
Parenchymatous cells are of frequent occurrence
in the xylem.
Known as wood parenchyma.
Cells are alive and generally thin walled.
23.
24. phloem
The philoem or bast is another conducting tissues
PHLOEM COMPOSED OF THE FOLLOWING
ELEMENTS:
Sieve tubes
Companion cells
Phloem parenchyma
Bast fibers (rarely)
25.
26.
27.
28.
29. Sieve tubes
Sieve tubes are slender,tube-like structures
It is also called sieve plate
Sieve plate is not transverse(horizontal)
Sieve plate of this nature is called a compound
plate
Sieve plate s covered by a deposit of
colourless,shining substance in the form of a pad,
called the callus or callus pad.
Carbohydrate called callose.
30.
31. Companion cells
Associated with each sieve lube and connected
with it by pores is a thin-walled,elongated cell
known as the companion cell.
The companion cell is present only in
angiosperm(both dicotyledons and
monocotyledon)
32.
33.
34.
35. Phloem parenchyma
Are always some parehymatous cells forming a
part of the phloem in all
dicotyledons,gymnosperm and ferns.
They stored up food material and help to conduct
it.
Absent in most monocotyledons.
36. Bast fibers
Sclerenchymatous cells occuring in the phloem or
bast are known as bast fibers.
37.
38. Types of vascular bundles
Radial vascular bundles : when the xylem and
phloem form separate bundles which lie on
different radii,alternating with each other, as n
roots.
Conjoint vascular bundles: it is called as
conjoint vascular bundles.
39. collateral
When the xylem and phloem lie together on the
same radius
Xylem being internal and the phloem external is
called collateral.
40.
41. bicollateral
The outer side of the xylem and again on the
inner side of it is called as bicollateral.
Bicollateral bundles are characteristics of
curubitaceae.
They are also often found in:
Solanaceae
Apocynaceae
Convolvulaceae
Myrtaceae
Etc.
Bundles is always open.
42.
43. Concentric vascular bundles
When one kind of vascular tissues(xylem or
phloem) is sorrounded by the other is cslled as
concentric vascular bundles.
The concentric bundles is to be
amphivasal(leptocentrc).
The xylem lies in the centre and sorround by the
phloem
The concentric bundles is to be
amphicribral(hadrocentric).
44.
45. Ground tissues system
System is represented by the
cortex,hypodermis,pith,mesophyll and portion of
midrib of leaves and comprises of the following
tissues.
