Plant Structure and Function:
Leaves
Cross-sections Comparing Monocot and Dicot Leaves
Which is the monocot? Which is the dicot?
Midrib (largest vein)
Mag. 40x
Clue: How does the vein
pattern differ between the two?
How would that show up in
the leaf cross section?
Monocot leaf xs
Epidermis
Stomata
Mag. 100x
Phloemlower layer
of cells in
the veins
Mag 400x
Xylem- top layer
of cells in the vein
Dicot leaf xs
Mag. 40x
Cuticle
Vascular tissue:
(Vein) made of
Upper epidermis
Xylem
Palisade mesophyll
layer
Phloem
Lower
epidermis
Stomata
Spongy Mesophyll
layer
Mag. 100x
Parts of the Leaf Magnified
Mag. 400x
Cuticle
Upper epidermis
Palisade layer
Xylem
Phloem
Spongy mesophyll
Lower epidermis
Stomata
Plant types by environment:
Xerophyte: Lives in dry biomes, what adaptations might it
have? Example on slide: Beach (dune) grass, grows
along beaches.
Hydrophyte: Lives water or wet habitats, what adaptations
might it have? Example on slide: Water lily- the leaf
floats on top of the water.
Mesophyte: Lives in biomes with moderate rainfall, what
adaptations might it have? Example on slide: Privet- grown
as a landscape plant for hedges.
SAMPLE#1
Leaf types
Based on adaptations of the leaf
form a hypothesis on which is
the hydrophyte, mesophyte, and
xerophyte.
SAMPLE #2
Mag 40x
Sample #3
Clues for Plant #1
Stomata: why would the
stomata be on the top?
Upper
epidermis
Mag 400 x
Mag. 100X
Lower epidermis: are there any
Stomata? Why not?
Note: Large air spaces in spongy
mesophyll why might this be
helpful?
Clues for Plant #2
Leaf is rolled
up.
Mag 40x
Stomata at the
base of deep pits.
What would that
do to the relative
humidity near the
stomata? How
would that effect
water loss by
transpiration?
Mag, 400x
Mag. 100 x
Lower epidermis
on the inside
of the rolled leaf,
How would that
effect the rate of
transpiration?
Clues for Plant #3
Leaf flat, increases exposure to
sun and environmental conditions
Mag. 100x
Stomata in lower epidermis
Mag. 40x
Final Comparison:
Give your answer- which one
is the hydrophyte, the
mesophyte, and the xerophyte