Plant Cells
and
Tissues
I. General Information
A. Three main plant cell types
1. Parenchyma
2. Collenchyma
3. Sclerenchyma
1. Parenchyma
a. Can differentiate into all
cell types
a. Living cell, can still divide
b. F(x)s =




Plant growth
Food production (photosynthesis)
Food storage (e.g. potatoes)
Wound healing & regeneration
2. Collenchyma
a. Living cells
b. Have thicker walls than
parenchyma
c. Can form long rope-like fibers
(e.g. linen)
d. Can stretch (occur in elongation zones)
e. F(x) = strength, support, elongation
3. Sclerenchyma
a.
b.
c.
d.
Usually dead while functioning
Thick secondary wall, no stretch
F(x) = strength, support
2 types:
i. fibers
ii. Sclereids
(seed coats,
nut shells
& fruit)
I. General Information
B. Three main types of plant tissue
1. Ground tissue
2. Dermal Tissue
3. Vascular Tissue
C. Ground tissue
1. Surrounded by
dermal tissue
2. All tissue that is
NOT dermal
tissue or vascular
tissue
C. Ground tissue
3. Contains all three types of cells
(mostly parenchyma)
4. Make up most of non-woody
roots, stems & leaves
C. Ground tissue
5. Many f(x)s
 Photosynthesis
 Food storage
 Support
C. Ground tissue
D. Dermal Tissue
1. General
a. Forms the “skin”
(outside covering) of a plant
b. Covers roots, stems & leaves
c. F(x) depends on
location
D. Dermal Tissue
d. Examples:
 Epidermis
 Cuticle
 Root Hairs
 Stomata
 Cork
D. Dermal Tissue
2. Epidermis
a. Parenchyma
b. Usually ONE
cell thick
c. Outer protective
covering of young
& mature woody
plants
D. Dermal Tissue
3. Cuticle
a. Waxy layer
secreted
by
epidermis
b. F(x) =
prevent
dehydration
D. Dermal Tissue
4. Root Hairs
a. Modification
of epidermis
b. F(x) =Absorption
of water from soil
D. Dermal Tissue
5. Stomata
a. Location = stems
&
leaves
b. F(x) =
osmoregulation &
regulation of
gas exchange
D. Dermal Tissue
c. Composition:
 two guard cells
 stoma (opening)
Guard cells
stoma
D. Dermal Tissue
6. Cork (bark)
(Dead cells)
a. F(x) =
i. Replace
epidermis
in woody
stems &
roots
ii. Protect
plant
cork
E. Vascular Tissue
1. F(x)s
a. Transports water & nutrients
b. Supports the plant
E. Vascular Tissue
2. Two kinds of vascular tissue
a. Xylem
b. Phloem
E. Vascular Tissue
3. Xylem
a.F(x) =
Conducts
Water & Nutrients UP
from roots
(X elevator only goes up)
3. Xylem
b. Two kinds of conducting cells
i. Tracheids
long, thick-walled
scelerenchyma
Thin separations
between them
i. Tracheids
 Water
moves
between
them
through
PITS
(thin porous
areas of
cell wall)
3. Xylem
 ii. Vessel
Elements (members)
 Short, wide sclerenchyma
 No end walls
 No separations btwn. them
(arranged end to end)
 Not found in Gymnosperms
Tracheids vs
Vessel Elements
4. Phloem
a. F(x) =
conducts the
Products of
Photosynthesis
in every direction
(P elevator moves in every direction)
4. Phloem
b. Two kinds of conducting cells
1. Sieve Tube Member
a. F(x) = Conduct sap
b. Stacked to form long
SieveTubes
4. Phloem
2. Companion Cells
a. Parenchyma
b. F(x) = Control movement of
sap through sieve tubes