Wood Formation (3)

Question 1

What is wood tissue comprised of? (2)

Answer 1

• Xylem.

* Phloem.

Question 2

What does wood tissue form from?

Answer 2

Secondary growth.

Question 3

What does secondary growth do?/Function?

Answer 3

Increases root width & stem width.

Question 4

Primary function of secondary growth?

Answer 4

Structural support.

Question 5

Where do we find secondary growth?

Answer 5

In:
• Gymnosperms.
• Angiosperms.

Question 6

What is the secondary meristem of these two groups (gymnos & angios) called?

Answer 6

Cambium.

Question 7

What is the cambium?

Answer 7

= a lateral meristem that forms a cylinder.

Question 8

What is wood?

Answer 8

= fibrous material formed by the accumulation of secondary tissue.

Question 9

What does wood tissue comprise of from the wood tissue diagram? (8)

Answer 9

• Sapwood.
• Heartwood.
• Rays.
• Periderm.
• Cork.
• Vascular cambium.
• Bark.
• Pith.

Question 10

What is Sapwood?

Answer 10

= the outer part of the xylem that still functions.

Question 11

Heartwood?

Answer 11

= the innermost tissue of woody plants that stops functioning in water transport.

Question 12

Why is Heartwood darker in colour than Sapwood?

Answer 12

It has resin & gum.

Question 13

Bark?

Answer 13

= outer protective layer of trees.

Question 14

Bark = …?

Answer 14

= living Phloem.

Question 15

Periderm = …?

Answer 15

= Cork cambium.

Question 16

What is Cork cambium?

Answer 16

= outer layer of vascular cambium.

Question 17

What cells are found in the Cork cambium?

Answer 17

Vascular cambium cells.

Question 18

What is the vascular cambium?

Answer 18

= structure that is found inside the cork cambium.

Question 19

Function of vascular cambium?

Answer 19

To produce secondary xylem & phloem.

Question 20

What do secondary xylem & secondary Phloem do?

Answer 20

● Secondary xylem
= produces wood.

● Secondary phloem
= forms part of bark.

Question 21

What happens to the vascular cambium every winter?

Answer 21

It ceases to grow every winter of each year.

Question 22

Describe the secondary xylem? (3)

Answer 22

• Small.
• Thick walls.
• Darker.

Question 23

What do the walls of the secondary xylem form?

Answer 23

Annual rings.

Question 24

Describe the vascular cambium cells that are produced when growth resumes. (2)

Answer 24

• Large.

* Thin walls.

Question 25

What do the vascular cambium cells do? Function?

Answer 25

Produce wax layer & lignin as they mature.

Question 26

What do vascular cambium cells replace?

Answer 26

Replace the epidermal cells produced during primary growth.

Question 27

What happens to the vascular cambium cells when they mature?

Answer 27

They die.

Question 28

Lay out the “process” of the Cork cambium formation? (5)

Answer 28

• Vascular cambium cells found in vascular cambium replace the epidermal cells produced during primary growth.
• the cells produce layers of wax & lignin as they mature.
• cells then die at maturity.
• after cells die and more cells are produced, the old one cracks+flakes.
• outer bark is formed.

Question 29

What is pith?

Answer 29

= the very center of a tree.

Question 30

Pith = …?

Answer 30

Pith = oldest part of a tree.

Question 31

What do the rays do in wood? (2)

Answer 31

• Store food material of the tree.

* Distribute food material of the tree horizontally.

Question 32

What does cork do? (2)

Answer 32

• Protects woody plants from disease.

* Prevents excessive water loss in woody plants.

Question 33

What 2 cells does the vascular cambium have?

Answer 33

• Vascular cambium cells.

* Companion cells of xylem.

Question 34

What do the companion cells of the xylem do?

Answer 34

They form Ray’s in secondary growth.

Question 35

What do the xylem rays do?

Answer 35

Transport material laterally.