Xylem and phloem

1.

XYLEM AND PHLOEM

2.

Lesson objectives
To compare the structure of elements of
xylem and phloem.

3.

How does water rise on a tree
overcoming the gravity?

4.

How transport of materials take
place in the plants?
Plants have vascular tissue that transports
water, materials, nutrients within the plant
body.

5.

There are two types of vascular
tissue:
1.
Xylem Phloem

6.

1) XYLEM
Xylem’s function
Xylem transports water and mineral salts
from the roots up to other parts of the
plant.
Direction of movement in xylem is ONLY
upward.

7.

Xylem structure
Consists of:
1.
Vessel elements:
transports water with higher
efficiency
2.
Tracheid: transports water
with lower efficiency

8.

Xylem’s structure
Mature xylem
consists of elongated
dead cells, arranged
end to end to form
continuous vessels
(tubes).
Mature xylem
vessels contain no
cytoplasm

9.

2) PHLOEM
Phloem’s function
Phloem transports sugars
synthesized during
photosynthesis up and down
the plant.
This means, for example, that
sucrose is transported:
from the root to the leaves in
spring time
from the leaves to the root in
the summer

10.

Phloem’s structure
Phloem consists of living cells
arranged end to end.
Unlike xylem, phloem vessels
contain cytoplasm, and this
goes through holes from one
cell to the next.

11.

1) Phloem
Consists of:
1.
Sieve tube
elements (sieve
cells): transport
materials.
2.
Companion cells:
control and nourish
sieve cells.

12.

Let’s do the activity on p. 51

13.

Homework
Read p.50-51
Literacy on p. 51
New words