Xylem

A group of cells which are similar in Origin and function but of more than One type in structure.
Water conducting tissue
Along with phloem make vascular tissue
Provide support to plants
1)Tracheary elements
These are nonliving cells, provide support and conduct water. Two types,

(a)Tracheids: elongate, tube like cell, tapering, rounded or oval ends, hard lignified walls.

(b)Vessels members: long, cylindrical, tube-like structures with lignified walls.
(2)Fibres: thick walls, evolve from tracheids and provide mechanical strength. Two types,

(a)Fibre-tracheids: medium thickness walls, have reduced boardered pits.

(b)Libriform fibres: very thick walls, have reduced simple pits.
Parenchyma cells: living cells, in woody plants, store of food in starch form. Two types:
(a)Axial parenchyma: derived from fusiform initials, have tracheary elements and fibres.

(b)Ray parenchyma: derived from ray initials of cambium, xylem ray cells.
Developmentally, xylem have two types

(1)Primary xylem: derived from procambium, developing from embryo, non-woody plants.
(2)Secondary xylem: from vascular cambium, second stage of plant development, in woody plants.

1. Xylem
Farah Naz #19
Life Sciences
IUB

2. Xylem
•Term introduce by Nageli(1858).
•Greek xylos meaning wood.

3. •A group of cells which are similar in Origin
and function but of more than One type in
structure.

4. Functions of xylem
•Water conducting tissue
•Along with phloem make vascular tissue
•Provide support to plants

5. Elements of xylem
•1)Tracheary elements
These are nonliving cells, provide support and
conduct water. Two types,
(a)Tracheids: elongate, tube like cell, tapering,
rounded or oval ends, hard lignified walls.
(b)Vessels members: long, cylindrical, tube-like
structures with lignified walls.

6. Elements of xylem
•(2)Fibres: thick walls, evolve from tracheids
and provide mechanical strength. Two types,
•(a)Fibre-tracheids: medium thickness walls,
have reduced boardered pits.
•(b)Libriform fibres: very thick walls, have
reduced simple pits.

7. Elements of fibres
•Parenchyma cells: living cells, in woody
plants, store of food in starch form. Two
types:
•(a)Axial parenchyma: derived from fusiform
initials, have tracheary elements and fibres.
•(b)Ray parenchyma: derived from ray initials
of cambium, xylem ray cells.

8. Types of xylem
•Developmentally, xylem have two types
•(1)Primary xylem: derived from procambium,
developing from embryo, non-woody plants.
•(2)Secondary xylem: from vascular cambium,
second stage of plant development, in woody
plants.

9. Thank You

10. Thank You