Stems

Question 1

The shoots (stems) consist of \_\_\_\_\_ (where leaves and axillary buds are produced) separated by \_\_\_\_.
Therefore they are \_\_\_\_.

Answer 1

Nodes
Internodes
Articulated

Question 2

Shoot apex

• Devoid of:
• Produces:

Answer 2

• A cap

- Both stem and leaf simultaneously

Question 3

Forms primary structure of stem (and roots)

Answer 3

Protoderm, ground meristem, procambium

Question 4

What do leaves develop from

Answer 4

primordia

Question 5

Intercalacary meristem

Answer 5

Cell division growth and regrowth at nodes

Question 6

Primary structure stem epidermis always has

Answer 6

a cuticle

Question 7

Primary structure stem cortex consists of

Answer 7

a chlorencyma or fibers along the stem ridge

Question 8

Primary structure vascular cylinder

Answer 8

Vasuclar bundles embedded in a pith

Question 9

Primary xylem and phloem are grouped together in units called

Answer 9

bundles

Question 10

Collateral bundles

Answer 10

phloem oriented towards the exterior and xylem towards the interior.

Question 11

primary xylem within the bundles in stems

Answer 11

is endarch, from the interior to the exterior

Question 12

Monocot vs. eudicot vascular bundles

Answer 12

M: Scattered or pith parenchyma
E: Circle or ring

Question 13

Monocots collateral bundle

Answer 13

Closed - intrafascicular vascular cambium does not differentiate b/w px and pp

Question 14

Dicot collateral bundle

Answer 14

Open - between primary phloem and xylem

Question 15

Intra vs. Inter f.v. cambium primary structure

Answer 15

• within the collateral bundles b/w phloem and xylem
• b/w vascular bundles
• connects to form a secondary meristimatic ring

Question 16

Intra vs. Inter f.v. cambium secondary structure

Answer 16

• V.C. produces 2p to the exterior which crushes and overlaps 1p
• V.C. produces 2x towards interior which pushes the 1x inside
• much more xylem and phloem

Question 17

Stems remain herbaceous because…

Answer 17

V.C. produces little 2x, no periderm, no C.C.

Remains herbaceous and destroyed during the winter

Question 18

2nd structure in woody plants

• 2x =
• Bark develops from…

Answer 18

• Produce a lot of 2x and form annual rings
• 2x = wood
• Bark develops from C.C. but at the exterior so stems become woody and survive the winder

Question 19

Bark:

• Outer side layer of cork cambium
• Inner?
• Periderm?

Answer 19

cork cells impregnated with suberin
phelloderm
Every year it develops on the interior of the previous one; outer periderm breaks and exfoliates (contains C.C., phelloderm, all its products)

Question 20

Bark of the birch tree

Answer 20

Protects the inner tissues against cold and insects, filters UV radiation

Question 21

Willow tree asprin

Answer 21

Willow bark contains tannins and salicin
Salicin hydrolyzed to salicyl alcohol, becomes salicylic acid
- Lasts longer than asprin

Question 22

Precious bark

Answer 22

Quinine - treats malaria

Question 23

Specialized stems - Rhizomes

Answer 23

• Underground stem - distinct internodes has leaves

Question 24

Underground stems

Answer 24

ensure the survival of herbaceous perennial plants during the winter. They store food reserves and they have buds from which shoots/flowers will develop in next spring. Also, underground stems allow vegetative propagation.

Question 25

Runners (e.g. strawberries) and stolons

Answer 25

Elongated internodes

- S: Underground, R: above

Question 26

Tuber (e.g. potato)

Answer 26

swolllen tip of a stolon

Question 27

Bulbs?
Layered?
Scaly?

Answer 27

• Short, disk-like, surrounded by thick, fleshy, modified leaves
• bulb leaves cover entirely each other (onion, tulip)
• Only partly each other (lillies, garlic)
• Have adventitious roots

Question 28

Corms

Answer 28

Short, erect, underground fleshy stem covered with thin, dry leaves called tunics

Question 29

Cladophylls

Answer 29

Compressed stems that resemble leaves

They do photosynthesis like normal leaves, but also they are succulent and store water

Question 30

Succulent stems

Answer 30

Accumlate water

Question 31

Honey locust

Answer 31

stem with spine - defense against heribivory