Leaf structure

leaf structures and functions

1. © 2004 Plano ISD, Plano, TX

2. © 2004 Plano ISD, Plano, TX
Why is a leaf like a sandwich?Why is a leaf like a sandwich?

3. © 2004 Plano ISD, Plano, TX
contains cells
which secrete a
waxy substance
called a cuticle
which prevents
water loss
upper epidermis
mesophyll
contains vascular
tissue (veins) and
2 types of cells
containing
chloroplasts
contains stomata,
guard cells
lower epidermis
Layers of a LeafLayers of a Leafchloro
chloro
phyll
phyll
chlorochlorophyllphyllphyll -o,
phyll -o,
(G suffix) a leaf
(G suffix) a leaf phyll -o, phyll -o, (G suffix) a leaf(G suffix) a leaf
phyll

4. © 2004 Plano ISD, Plano, TX
cuticle
upper epidermal
cells
palisade cells
chloroplasts
vascular tissue
spongy cells
air space
lower epidermal
cells
guard cell
cuticle
Parts of a LeafParts of a Leaf
stomata
chloro

5. © 2004 Plano ISD, Plano, TX
Guard CellsGuard Cells
guard cell
stomata
epidermal cell

6. © 2004 Plano ISD, Plano, TX
Photosynthesis occurs in Photosynthesis occurs in
chloroplasts.chloroplasts.
Chloroplasts are found in 3 types Chloroplasts are found in 3 types
of cells.of cells.
palisade spongy mesophyllguard

7. © 2004 Plano ISD, Plano, TX
Most photosynthetic activity occurs Most photosynthetic activity occurs
in the palisade cells.in the palisade cells.
Describe the Describe the structurestructure of palisade of palisade
cells.cells.
verticallong, narrowlined up at top of leaf nearer to sun
Count the palisade cells.Count the palisade cells.
more chloroplasts than spongy mesophyll
and guard cells
20!

8. © 2004 Plano ISD, Plano, TX
Count the palisade cells.Count the palisade cells.
Which alignment is better?

9. © 2004 Plano ISD, Plano, TX
O
2
O
2
O
2
O
2O
2O
2O
2O
2O
2O
2O
2O
2O
2
O
2
O
2O
2O
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
CO
2CO
2
CO
2
CO
2
CO
2
CO
2
CO
2
Gas movement and exchange occur Gas movement and exchange occur
in the mesophyll layer.in the mesophyll layer.

10. © 2004 Plano ISD, Plano, TX
Sandwich:Leaf AnalogySandwich:Leaf Analogy
upper epidermal cellsbread
palisade cellspeanut butter
jelly spongy mesophyll cells
bread lower epidermal cells
Why is a leaf like a sandwich?Why is a leaf like a sandwich?

11. © 2004 Plano ISD, Plano, TX
Complete this analogy.Complete this analogy.
sandwich:leaf::baggie:______cuticle

12. © 2004 Plano ISD, Plano, TX

13. © 2004 Plano ISD, Plano, TX
lower epidermislower epidermis
1
2
3
4
5
6
7
8
10
11
12
1314
9
guard cellsguard cellspalisade cellspalisade cellsair spaceair spacemesophyllmesophyllchloroplastschloroplastslower epidermal cellslower epidermal cellsupper epidermisupper epidermisspongy mesophyll cellsspongy mesophyll cellsvascular tissue (vein)vascular tissue (vein)stomatastomataupper epidermal cellsupper epidermal cellscuticlecuticleIdentify.Identify.

14. © 2004 Plano ISD, Plano, TX
Identify.Identify.
1
2
3
4
5
6
7
8
10
11
12
1314
9

15. © 2004 Plano ISD, Plano, TX
1
2
3
4
5
6
7
8
10
11
12
1314
9
exact site of photosynthesisexact site of photosynthesisnoncellular waxy outer coveringnoncellular waxy outer covering3 cells containing chloroplasts3 cells containing chloroplastsloosely spaced cellsloosely spaced cells
regulate opening and closing regulate opening and closing
of stomataof stomata
allows for movement of gases allows for movement of gases
within leafwithin leaf
transports water, minerals, transports water, minerals,
food throughout leaf, plantfood throughout leaf, plant
OO
22 exits here exits herewater vapor exits herewater vapor exits hereCOCO
22 enters and exits here enters and exits hereIdentify.Identify.

16. © 2004 Plano ISD, Plano, TX