Xylem Flashcards
How are xylem vessels formed
a column of tubular cells which end cross-walls
breakdown causing cells to combine and form a
continuous long tube
What are xylem vessels walls strengthened by?
deposition of lignin
What are xylem vessels composed of?
dead cells with no protoplasm
What adapts xylem vessel for their functions
Tracheids
Difference between xylem vessel and thracheids
Elongated spindle-shaped single cells with tapering end
walls which overlap to increase strength
Less efficient than vessels as has to move through smaller pits
What are xylem fibres similar to
sclerenchyma fibres
Xylem fibre characteristics
Dead cells with thick lignified walls
Xylem fibre functions
Help to support the plant body and are not involved in water
transport
Xylem parenchyma function and characteristics
Living cells
Act as a packaging tissue in the primary xylem
What happens in secondary xylem.
parenchyma cells form radial medullary rays
Function of radial medullary rays
Radial transport of food, water, gases and food
storage
Function of Xylem
To transport water and mineral salts from the roots to the aerial
parts of the plant
To give mechanical support. The lignified walls enable xylem vessels
and tracheids to resist compression and tension
Types of xylems
Primary:
Protoxylem
Metaxylem
Secondary.
