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Leaves (External structure foliage (veins (collects sugars produced by…
Leaves
External structure foliage
can't lose a lot of H2O
can't allow bacteria, fungi or algae in
can't be too nutritious to animals
Photosynthesis would be unless
absorb CO2
converts carbohydrates via light energy
Leaf Blade
light harvesting portion
lamina
lower side of blade
dorsal surface
large veins protrude like a backbone
ventral surface
upper side
adaxial
smooth to touch
petiole
Salk
holds blade out to the light
prevents shading
flexible for wind blowing
keep insects off
sessile leaf
no petioles
small/ very long/ narrow
sheathing of blade leaf
leaf wraps around base
can flex and flutter
compound or simple
simple
blade is one part
compound
blade divided into many parts
tough
small blades called leaflets
attached by petiolule
extensions of petioles called rachis
veins
bundles of vascular tissue
distribute H2O to the leaf
collects sugars produced by photosynthesis
eudicots
reticular venation
process is in the netted pattern
monocots
parallel venation
runs side by side
abscission zone
perpendicular to the petiole
cuts off leaf when useful life is over
leaf scar
undamaged cells swell
become corky
forms protective scar tissue
Internal structure foliage
epidermis
transportation
water loss through epidermis
serious problem when soil is dry
must be translucent and waterproof
large flat tubular epidermal cells
guard cells
granular and nongranular
stomata
sucked into epidermis
region of nonmoving air
oleander
lower leaf epidermis
many crypts
area where epidermis is deep in the leaf
hairy
trichromes
provides some shade on leaf
blocks excessive sunlight
become more vulnerable to their predators
mesophyll
ground tissue
palisade parenchyma
upper surface
main photosynthetic tissue
separated slightly
exposure to intercellular surfaces
one layer thick
spongy mesophyll
lower portion
open lose aerenchyma
CO2 diffusion fast
is either located in the center or lacking all together
vascular tissues
between the palisade and spongy mesophyll
midrib
lateral veins emerge
move to minor veins
responsible for release of H2O
H2O from xylem sugars from phloem
envolved in conduction
morphology and anatomy of other leaf types
succulent leaves
family: crasslaceae
thick & fleshy
reduces surface to volume ratio
H2O conservation
Circular shaped
few air spaces
H2O lose through stomata
sclerophyllous
use own construction and metabolism
hardness protects against animals, fungi, bacteria
bed scales
most common modifications
dormant shoot apical meristems
protected from low temperatures and drying
small and not compound
petiole are small or nonexistent
tough waxy leaves for protection
tendrils
grows indefinitely
cells that sense contact
causes that side to stop growing
other side grows
plant begins to coil
insect traps
trap and digest insects
thin leaves
capable of photosynthesis
lamina secretes watery digestive
absorbs instead of impermeable
initiation and development of leaves
basioangiosperm
eudicot
leaf primordium
protoderm growing outward
grows fast
contains ground meristem & protoderm
all are meristematic
increases in thickness
monocots
apical meristem adjacent to protoderm
hook like shape
cylinder that encircles the shoot apical
some become broad and expand
basil expansion
protaoxylem
protophloem
stretched and disrupted by Basal meristem
