Chapter 7 - Leaves Flashcards
What function:
o Harvest energy light
o Synthesize glucose from CO2 and H2O
Photosynthesis
What function:
o Release H2O from stomata
o Maintains root pressure & cools leaves
Transpiration
What function:
o Stomates also regulate gases
o Input CO2 & export O2
Gas exchange
What are these called:
o Some leaves modified for different functions
o Tendrils, bracts, succulents, spines, and flytraps
Specialized leaves
LEAVES:
May be long, short, or absent
It’s the stock part
Petiole
LEAVES:
Outgrowths at petiole base
Stipules
LEAVES:
Aka lamina
Main flattened part that you think of
Blade
LEAVES:
* Part of the blade closest to the petiole
Base
LEAVES:
* Part of blade farthest from petiole (tip)
Apex
LEAVES:
* Leaf perimeter between the apex and base
Margin
LEAVES
* Branching network of vascular tissue
Venation
LEAVES
* Middle vein (continuous of the petiole)
Midrib
Leaf with a single blade
Simple leaf
Smaller leaflets. Its like a bunch of simple leaves on a stick/petiole
Evolved for windy areas
Compound leaf
LEAF SHAPES:
* Leaflets radiate from end of petiole
palmate
LEAF SHAPES:
* Feather like (think mimosa tree)
* Leaflets arranged along midrib
Pinnate
LEAF ATTACHMENT:
leaf base attached directly to stem
Sessile
LEAF ATTACHMENT:
attached to stem by petiole
petiolate
LEAF BLADE SHAPE:
smooth edge w/o teeth or lobes
entire
LEAF BLADE SHAPE:
saw like edge around full leaf. Teeth vary in size and shape.
toothed/serrated
LEAF BLADE SHAPE:
Margin undulates up & down. Not really lobes
Wavy
How are the veins in monocots and dicots different?
Monocots are vertical whereas the dicots are wild
arrangement of leaves at nodes
phyllotaxis
o One leaf per node
o _______ on opposite sides up stem
Alternate
two leaves per nide arranged on opposing side
Opposite
three or more leaves at each node
Whorled
LEAVES:
Aka bifacial leaf
_________ & _______-sides are different
Dorsiventral leaf
LEAVES:
Aka equifacial leaf
Similar dorsal & ventral sides
Isobilateral leaf
LEAF DICOTS:
* Thick layer of cuticle
* Lack chloroplasts
* Stomata generally absent
* Trichomes & glandular hairs possible
* Function: protection and water conservation
Upper epidermis
LEAF MONOCOTS:
Cuticle usually thicker on upper side
Equifacial is similar top and bottom
Stomata on both sides & arranged in rows
Bulliform
leaf tissue - epidermis
LEAF MONOCOTS:
What is Bulliform?
Bulliform cells are bubble shaped cells
* On upper side of lead near midriff
* BC open & close leaf depending on H2O
LEAF MONOCOTS:
Not stratified
Layer of loose oval collenchyma cells
Not stratified into palisade & spongy
Air gaps smaller than dicot
Leaf tissue - mesophyll
LEAF MONOCOTS:
Many bundles arranged in parallel series
Central bundle usually largest in size
Bundles are conjoint, collateral, and closed
Xylem on top, phloem on bottom
Leaf tissue - vascular tissue
In leaves, which ‘cot has stomata on the lower surface ONLY?
Dicot
In leaves, which ‘cot has stomata on the lower surface AND upper surface?
Monocot
In leaves, which ‘cot has stomata in rows?
Monocot
In leaves, which ‘cot has stomata in a random arrangement
Dicot
In leaves, which ‘cot has Bulliform?
Monocot
In leaves, which ‘cot has a differentiated mesophyll?
Dicot
In leaves, which ‘cot has an undifferentiated mesophyll?
Monocot
In leaves, which ‘cot has smaller air spaces?
Monocot
In leaves, which ‘cot has a larger air space?
Dicot
In leaves, which ‘cot has reticulated venation?
Dicot
In leaves, which ‘cot has parallel venation?
Monocot
What does a palmate leaf look like?
A palm tree or poison oak. It is a bunch of leaves at the top of a stem like an umbrella
What does a petiolate leaf look like?
One leaf
What do pinnate look like?
A bunch of smooth leaflets
LEAF SHAPES/TYPES:
X is smaller (less surface area) & thicker, cuticle thicker
Y is large & thin, cuticle thinner
Sun (x) and Shade (Y) leaves
LEAF SHAPES/TYPES:
Dry adapted plant
Leaves smaller & thicker to save water
Thick cuticle & recessed stomata
Xerophytic leaves
LEAF SHAPES/TYPES:
Thin epidermis & lacks cuticle
Requires less vascular tissue
Absorb water & nutrients through epi by diffusion
Air space provides buoyancy
Hydrophytic leaves
What are the main 6 types of modified leaves?
~Tendrils (support and climbing)
~Bud scales (protect buds)
~Succulent (water conserving)
~Spines
~Floral bracts (poinsettia)
~Insect traps
What are the 2 reasons that plants lose their leaves
Cold and/or dry weather
What is leaf abscission?
“leaf drop”
When leaves go through abscission, where do they separate?
The base of the petiole
Where is the abscission zone?
The base of the petiole
What are the 3 steps of abscission?
Resorption
Protective layer formation
Detachment
LEAF FUNCTIONS:
* Chlorophyll broken down
* Some nutrients resorbed into plant
Resorption
LEAF FUNCTIONS:
* Cork layers form above & below the separation layer
* Protects stem after leaf fall
Protective layer formation
LEAF FUNCTION:
* Cells in separation layer secrete digestive enzyme
* Break up cells between protective layers
* Causes detachment of leaf
Detachment
LEAF ADAPTATIONS:
Slender twining appendage
Used for support in climbing vines
Tendrils
LEAF ADAPTATIONS:
External covering of bud
Protects against cold & desiccation
Bud scales
LEAF ADAPTATIONS:
NOT THORNS (those are stems)
Rigid extensions with sharp ends
They slow down air movement for water conservation
Potentially radiates heat out
Herbivory defense
Collects water by allowing it to drip
Spines
LEAF ADAPTATIONS:
Succulents use thick, fleshy leaves to store water
Adaptation for arid environs
Water conservation
LEAF ADAPTATIONS:
Create chambers or snares for catching insects
Used by carnivorous plants
Insect tracts
LEAF ADAPTATIONS:
Colorful, petal-like parts of petals
Attract pollinators
Floral bracts
What do the lobes of a simple leaf like?
Unlobed (the smooth wavy ones are lobed. The gaps between lobes are sinuses)
Lobed (blade with distinct protrusions)
Dissected/parted (blade deeply cut into partitions)
