The Vascular System
What two types of tissues make up the
vascular system in plants?
Xylem and Phloem
What is xylem?
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Water and dissolved minerals move up
from the roots to the rest of the plant
through xylem.
What are the two types of cells that make
up xylem?
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Tracheid cells and vessel elements.
Tracheid Cells and Vessel Elements
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Tracheid Cells:
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Long and narrow.
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Water flows from cell to cell through
openings in the thick cell walls.
Vessel Elements:
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Shorter and wider than tracheids.
Both cells must die before water moves
through them.
How do plants move water through
xylem?
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Cohesion-tension theory proposes that the
physical properties of water allow the rise
of water through the plant.
What does this mean?
Cohesion: attraction btw molecules of the
same substance.
Adhesion: attraction btw molecules of
different substances.
For Example.....
Give an example cohesion and an
example of adhesion.
So Back to the Cohesion-Tension
Theory
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Simply put..... cohesion and adhesion
create tension that moves water upward in
xylem.
There is one more force that drives the
movement of water in plants.....
transpiration
Plant Sweat
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Transpiration is how plants sweat.
Release of vapor through the pores of the
skin or stomata of plant tissue.
What role does evaporation play?
Phloem

Phloem carries sugars from
photosynthesis throughout the plant,

Phloem tissue is alive.

Made of cells called sieve tube elements.
Sieve Tube Elements
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Get their name from small holes in the end
walls of their cells.
As they grow these cells lose their nuclei
and ribosomes.
How does food move through
phloem?
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The pressure-flow
model explains how
food, or sap, moves
through a plant.
The food moves
from an area of high
pressure to an area
of low pressure