Secondary Growth

Question 1

What is secondary growth?

Answer 1

produces wood and cork to increase girth

Question 2

What is secondary tissue?

Answer 2

derived from lateral meristem called vascular cambium

Question 3

What does the vascular cambium produce?

Answer 3

secondary xylem called wood

Question 4

What is the cork cambium?

Answer 4

produces bark tissues which replaces the epidermis in stem and root

Question 5

Where does newer vascular tissue develop?

Answer 5

xylem on the inner, phloem on the outer of the vascular cambium, at the top part of the tree

Question 6

Where is the oldest tissue?

Answer 6

furthest away from the cambium, in the core or the primary epidermis and ground tissue

Question 7

WHen did woody plants evolve?

Answer 7

1. lepidodentron- lycophyte
2. horsetail/ tree ferns- ferns
3. lignophyte- gymonsperm and angiosperm

Question 8

Why is the older tissue at the base?

Answer 8

primary growth

Question 9

Why is there secondary xylem at the base, but not at the top?

Answer 9

because they have more time to develop, creating a thicker base.

Question 10

When does secondary growth stop?

Answer 10

when cambium breaks as it pushes outward

Question 11

Three ways to cut wood

Answer 11

cross section
radial
tangential

Question 12

How is cross-section cut?

Answer 12

(cutting it through the side to see the annular rings) (wood will have annular rings)

Question 13

How is radial cut?

Answer 13

(cutting from the center going down) (wood will have straight lines)

Question 14

How is tangential cut?

Answer 14

(vertical going down, but not through the center) (wood pattern is oval, due to the base being wider, and the tissues growing on a slant

Question 15

What are wood rays?

Answer 15

group of parenchyma cells that radiate across the stem from the center

Question 16

WHat is uniseriate rays?

Answer 16

one line of cells

Question 17

What is multiseriate rays?

Answer 17

multiple lines of cells

Question 18

Where are ray cells formed?

Answer 18

vascular cambium

Question 19

What are ray initials?

Answer 19

Cambium that form into rays

Question 20

What are fusiform intials?

Answer 20

cambium that forms vascular tissue

Question 21

WHat is periclinal division?

Answer 21

cambium dividing to add xylem, longitudinally and radially. Ray intials form this way, but are short and cuboidal.

Question 22

What is anticlinal division?

Answer 22

cambium formation to increase parameter of cambium

Question 23

What do wood cells include?

Answer 23

secondary xylem, rays, fiber, xylem parenchyma, laticifers, resin, and gum duct epithelial cells

Question 24

What is hardwood?

Answer 24

harder texture because of secondary growth tough with many fibers, vessels present, angiosperm

Question 25

What is softwood?

Answer 25

lack of fibers, absent vessels, gymnosperm

Question 26

What is heartwood?

Answer 26

darker, heavier, tylosis (the process of filling dead xylem and phloem to prevent possible invaders)

Question 27

What is sapwood?

Answer 27

lighter in color and weight, living cells

Question 28

What is early wood?

Answer 28

spring wood, big cavity, thin walls

Question 29

What is late wood?

Answer 29

summer wood, small cavity, thick walls

Question 30

Where is cork cambium found?

Answer 30

around and outside the primary phloem, outside the vascular cambium

Question 31

What is lenticel?

Answer 31

crack in the epidermis as the tree grows wider

Question 32

What is the cortex?

Answer 32

Develops from the primary growth, activating the cortex as it expands

Question 33

What does the cork cambium do when activated?

Answer 33

produces cork cells to fill cracks and spaces as the epidermis breaks.

Question 34

What direction does cork cambium add to?

Answer 34

outerside

Question 35

What is the outerbark?

Answer 35

outside the cork cambium,
falls off naturally

Question 36

What is the inner bark?

Answer 36

cork to vascular cambium, majority is phloem

Question 37

What is anomalous/tertiary growth?

Answer 37

growth creating unusual patterns, like clusters of xylems with multiple vascular cambiusm

Question 38

What is the order of the stem?

Answer 38

pith
primary xylem
secondary xylem
vascular cambium
secondary phloem
fiber
primary phloem
cortex
cork
epidermis

Question 39

How does a tree grow taller?

Answer 39

• taller through primary growth of the apical meristem
  
  • the roots and shoots elongate thanks to plant hormones like auxins

Question 40

How does a tree grow wider?

Answer 40

secondary growth through cambium division