1. Leaf structure

2. Leaf Structures N K O C D I J M L E G G F F

3. Epidermal cells
Epidermal Cells –produce the waxy cuticle

4. Cuticle Cuticle –waxy (non-cellular layer)
Protects against excessive water loss and infection
Restricts gas exchange
Deters herbivores

5. Palisade Mesophyll Palisade Mesophyll
Cells are tightly packed together with lots of chloroplasts
Primary site of photosythesis

6. Spongy Mesophyll Spongy Mesophyll
Cells are loosely arranged with air spaces in between them
Fewer chloroplasts
Promotes rapid gas diffusion (CO2 and O2)

7. Guard Cells Guard Cells –size is depending on water content of plant
When full of water they push apart
When lacking water they come together
Control opening of stomata

8. Stomata Stomata- pores in the epidermis More located on lower surface
Where gas exchange takes place

9. Leaf Adaptations

10. Adaptations to SALT Mangrove Plants
Have special pores that excrete salt
Their leaves can tolerate to store high levels of salt
Restrict the openings of their stomata to preserve freshwater
Turn their leaves to reduce water loss

12. Adaptation to WATER Underwater plants
Leaves are flexible so they don’t break with currents
Air spaces in the leaf so they float (Hydrophilic)
Chlorophyll is restricted to the top layer

13. Adaptations to DRY Hairs on the leaf trap humidity
Waxy leaf surface to reduce water loss
Succulent leaves store water
Spines have less surface area

14. Extreme heat Example: Octillo shed leaves when it gets to hot
lays dormant
lowers metabolism

15. Adaptations for DROUGHT
Avoiders
Short lifespan
Wet season
Seeds survive drought
Drought deciduous species
Leaves shed in dry season

16. Adaptations for DROUGHT
Tolerators
Leaves transpire slowly
Change orientation of leaves
Sunken stomata
E.g. pines
More efficient photosynthesis

17. Adaptations in the RAINFOREST (Moist and shaded)
Waxy surfaces (drip tips) drain water to prevent fungal growth
Large surface area on leaves to absorb more light

18. Adaptations to BOREAL Cold and Dry
Extracellular freezing to protect cells
NEEDLE LEAVES
compact to protect vascular tissue
waxy cuticle protects the mesophyll & prevents water loss
prevent snow accumulation
Dark to absorb solar heat
Don’t shed = photosynthesis early in spring

19. Adaptations to the ARCTIC
Dark colours to absorb more solar heat
Covered in small hairs to conserve heat
Small surface area to prevent freezing

20. Adaptations to avoid BEING EATEN
Chemical Defence:
poison (poison ivy)
aromatic oils (eucalyptus)
alkaloids (tobacco)
Mechanical Defence
Spines / Thorns (ex: raspberry)

21. Hydrophytic

22. Mesophytic

23. xerophytic

24. Practice
Page
Page