Ex. 3 Plant Structure and Development

Question 1

what are the 2 main parts of the leaf?

Answer 1

blade

petiole (joins blade to stem at the node)

Question 2

terminal bud

Answer 2

a bud located at the apex (tip) of the stem. Terminal buds have special tissue, called apical meristem, consisting of cells that can divide indefinitely

Question 3

axillary bud

Answer 3

an embryonic shoot located in the axil of a leaf

-almost all branches in angiosperms begin as axillary buds

Question 4

lead primordia

Answer 4

developing leaves

-expand rapidly

Question 5

trichomes

Answer 5

tiny hairs on leaves

Question 6

shoot apical meristem

Answer 6

dome shaped mass of cells at the apex of the stem

• dark colored, stain darkly
• dense cytoplasm/small vacuoles

Question 7

axillary bud primordia

Answer 7

located in the axil of each leaf primordium

-will become apical meristems for new lateral branches

Question 8

protoderm

Answer 8

tissue that will give rise to the epidermis

-outermost layer of cells

Question 9

procambium

Answer 9

tissue that will differentiate into the vascular system of the leaves and stem
-darkly stained and run down the middle of the leaf primordia

Question 10

ground meristem

Answer 10

tissue that will become the pith and cortex of the stem and the mesophyll of the leaves
-any cells that aren’t protoderm or procambium

Question 11

epidermis

Answer 11

outermost layer of cells

Question 12

cortex

Answer 12

layer between epidermis and vascular bundles

-composed of parenchyma cells

Question 13

vascular bundles

Answer 13

found beneath the cortex

include xylem and phloem

Question 14

xylem

Answer 14

conduct water and minerals

• stain red in prepared slides (presence of lignin)
• found one layer deeper toward pith than phloem

Question 15

phloem

Answer 15

found right next to xylem closer to epidermis than xylem is

• conduct nutrients
• composed of sieve-tube elements and companion cells

Question 16

vascular cambium

Answer 16

located between xylem and phloem

-responsible for generating new vascular tissue

Question 17

pith

Answer 17

core of parenchyma cells in the center of the stem

Question 18

dermal tissues

Answer 18

1. epidermis (guard cells)

2. periderm (parenchyma, sclerenchyma, cork cells)

Question 19

ground tissues

Answer 19

parenchyma
collenchyma
sclerenchyma

Question 20

vascular tissues

Answer 20

xylem (tracheids, vessel elements)

phloem (sieve-tube elements, companion cells)

Question 21

what do roots do?

Answer 21

1. anchor the plant

2. absorb water and mineral nutrients from the soil

Question 22

what do stems do?

Answer 22

1. support and elevate leaves
2. transport water and nutrients
3. provide place for plants to keep flowers and fruits
4. keep leaves in the light

Question 23

root cap

Answer 23

The root cap protects the growing tip in plants. It secretes mucilage to ease the movement of the root through soil, and may also be involved in communication with the soil microbiota

Question 24

3 zones of growth in the root tip

Answer 24

1. zone of cell division (meristematic region, darkly stained)
2. zone of elongation (cells get longer)
3. zone of maturation (have root hairs)

Question 25

root hair

Answer 25

extensions of epidermal cells

• help hold the root in place/increase surface area for water absorption
• short lived

Question 26

endodermis of roots

Answer 26

circular bands of cells in the center of the root

• surround central vascular tissue
• cell walls of endodermis contain “suberin” which stain red
• suberin prevents water and minerals from flowing through the cell walls of the endodermis, forces them to move through cytoplasm

Question 27

“stele” of roots. what are the 3 main parts?

Answer 27

central tissue which contains vascular tissue

1. pericycle (undifferentiated perenchyma cells)
2. xylem (star shaped)
3. phloem (stained blue, found in between xylem)

Question 28

what are the 4 layers of leaves?

Answer 28

1. upper epidermis
2. palisade mesophyll (electrons bouncing, tightly packed)
3. spongy mesophyll (gas exchange, much space)
4. lower epidermis
   * cuticles also enclose the leaf

Question 29

stomata

Answer 29

found only in lower epidermis

• open and close for gas exchange
• contain guard cells

Question 30

cork and cork cambium

Answer 30

cork - layer of pink staining cells that cover the stem surface (about 5 cells deep)

cork cambium - directly beneath the cork, single layer of meristematic tissue that produces new cork cells

Question 31

define cotyldon

Answer 31

an embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed

Question 32

what are the two major subgroups of angiosperms?

Answer 32

monocots

eudicots