Stems

Question 1

What are the two different types of systems in plants?

Answer 1

Shoot system and Root system

Question 2

What is the structure called which attaches the leaf the the stem?

Answer 2

node

Question 3

What is the structure called which is located between specific leaves (on the stem).

Answer 3

internode

Question 4

What are the two types of buds in plants?

Answer 4

active apical bud
dormant lateral bud

Question 5

What is a different word used for “apical bud”?

Answer 5

terminal bud

Question 6

What important structures are present in the apical bud?

Answer 6

1. Apical meristem
2. Leaf primordium
3. Lateral axillary bud
4. Leaves covering the meristem

Question 7

What is the same in the root as well as the shoot tip? What is different?

Answer 7

The three primary meristems:
- protoderm
- ground meristem
- procambium

different locations.

Question 8

What is a major difference between the apical meristem in the shoot in comparison the the root?

Answer 8

The shoot meristem doesn’t have 4 separate zones, it only has the “growing and differentiation zone” and the “cell elongation zone”.

Question 9

What structure do young stems arise from? What structure do they have?

Answer 9

Young stems arised from apical meristems have primary structure.

Question 10

Explain the structure of monocot plants.

Answer 10

primary structure their whole life

Question 11

Explain the structure of dicot plants.

Answer 11

In divot plants, their stem evolves into secondary structure.

Question 12

What are the three primary meristems?

Answer 12

protoderm
ground meristem
procambium

Question 13

What are the three primary tissues?

Answer 13

epidermis
ground tissue
vascular tissue

Question 14

What is a major feature that distinguishes monocot from dicot stems?

Answer 14

The position of vascular bundles.

monocot: randomly arranged throughout the stem
dicot: positioned on the periphery

Question 15

What do both monocot and dicot stems contain?

Answer 15

vascular bundle (phloem and xylem)
epidermis
ground tissue (cortex and pith)

Question 16

What are the different types of vascular bundles?

Answer 16

simple

compound:
- concentric
–> hadrocentric (xylem inside)
–> leptocentric (phloem inside))
- collateral
–> collateral open (with vascular procambium)
–> collateral closed (without vascular procambium)

Question 17

What type of vascular bundles do all monocot stems have?

Answer 17

collateral closed (no vascular cambium)

Question 18

What are the main structures seen in the primary structure of the stem?

Answer 18

1) epidermis
2) cortex
3) stele

Question 19

What can be seen in the primary structure of the stem (more precise)?

Answer 19

1) epidermis
2) cortex
- cortex parenchyma
- endodermis
- sclerenchyma
3) stele
- vascular bundles
- pith parenchyma

Question 20

What changes occur between the primary and secondary structure? where do the changes occur?

Answer 20

only in DICOTS!
2 secondary meristems:
vascular cambium: xylem and phloem
cork cambium: epidermis–>periderm

Question 21

Explain the speciality of the secondary meristems. What do they produce?

Answer 21

vascular cambium:
- secondary xylem inside
- secondary phloem outside

cork cambium (phellogen):
- phelloderm inside
- phellem (cork) outside
(all known as periderm)

Question 22

What does xylem consist of?

Answer 22

• tracheids and vessels
• schlerenchyma cells (supportive tissue)
• parenchyma cells (for the collection of nutrients)

Question 23

What cells are known to be “supportive tissue”?

Answer 23

schlerenchyma cells

Question 24

What cells are known to be “for the collection of nutrients”?

Answer 24

parenchyma cells

Question 25

What does phloem consist of?

Answer 25

• sieve tube members (prolonged cells)
• companion cells (nutrient aid)
• schlerenchyma (supportive tissue)
• parenchyma cells (collection of nutrients)

Question 26

What cells are known to be “for nutrient aid”?

Answer 26

companion cells

Question 27

What cells are known for being “prolonged cells”?

Answer 27

sieve tube members

Question 28

What does a woody plant have?

Answer 28

alternating xylem and phloem layers!
- primary xylem and primary phloem in the center of the stem,
- secondary xylem making the annual rings of the tree,
- secondary phloem in the bark of the tree.

Question 29

What are lenticels?

Answer 29

Airy aggregations of cells on the surface of a stem or root. It functions as a pore, providing a medium for the direct exchange of gasses between the internal tissues and atmosphere.

Question 30

Distingush between primary and secondary tissue. When does the apical meristem begin producing cells? What cells?

Answer 30

• apical meristem doesn’t produce cells until the beginning of the growing season (protected by bud scales and primordia)
• when a bud begins to expand, apical meristems undergo mitosis
• 3 primary meristems develop
  1) protoderm (–> epidermis)
  2) procambium (–> primery xylem and phloem cells)
  3) ground meristem (–> pith and cortex (tissues composed of parenchyma cells))

–> means gives rise to

Question 31

What can the narrow band of cells between the primary xylem and phloem become?

Answer 31

vascular cambium

Question 32

What does vascular cambium become a component of?

Answer 32

secondary xylem and phloem.

Question 33

What arises from the vascular cambium (except of secondary xylem and phloem).

Answer 33

a second cambium, cork cambium, which produces:
- cork cells
- phelloderm cells

Question 34

What is heartwood?

Answer 34

older darker wood at the center

Question 35

What is sapwood?

Answer 35

lighter, still functioning xylem closest to the cambium

Question 36

What is refered to as the “bark” of the tree?

Answer 36

all tissues outside the cambium
- phloem
- cork
- cortex

Question 37

Explain the secondary growth of stems.

Answer 37

• epidermis is replaced by cork
• vascular cambium produces secondary xylem and phloem