leaves Flashcards
Chlorenchyma, flat thinleaf
Photosynthesis
the process by which plant loses water to serve the following purposes:
a. Continuous uptake of water
b. Cooling effects
c. Controls degree of saturation of cell with water
Transpiration
Economic uses of Leaves
Food
Herbs
Beverages
Teas
Drug uses
Uses of Leaves
Insecticides
Waxes
Aromatic Oils
Medical uses
Part of leaves
Lamina/ leaf blade
Petiole/stalk
flat, light harvestingportion
Lamina/ leaf blade
holds blade out into thelight
Petiole/stalk
With petiole
PETIOLATE
Without petiole
SESSILE
with one blade only
simple
a blade divided into leaflets
or pinnae or pinnule
compound
extension of the petiole to which the leaflets are attached
rachis
leaflets attach to individual rachis by petiolule
PINNATELY COMPOUND
leaflets attach to same point
PALMATELY COMPOUND
no stipule
Exstipulate
with stipule
- Stipulate –
Has petiole
With stipules that
protect shoot apical
meristem while leaf is
young
DICOT LEAF
Has leaf sheath
Has ligules
MONOCOT LEAF
one order of rachis
SIMPLE PINNATELY COMPOUND
-Bundles of vascular tissue
-distribute water from stem into leaf & collect
sugar produced and carry them to the stem
VEINS
leaf edge
MARGIN
outer end of leaf lamina
opposite end of the petiole
APEX
three leaflets
trifoliate
four leaflets
quadri/tetrafoliate
two orders of rachis
primary leaflet and secondary leaflet
BIPINNATELY COMPOUND LEAF
with 5 or more leaflets
pentafoliate
a compound leaf of having three order
TRIPINNATELY COMPOUND LEAF
three order of
rachises:
o primary rachis
o secondary rachis
o tertiary rachis
arrangement of leaves on the stem
PHYLLOTAXY
leaflets are attached to the end of the petiole
PALMATELY COMPOUND LEAVES
types of PALMATELY COMPOUND LEAVES
bifoliate
trifoliate
quadri/tetrafoliate
pentafoliate
two leaflets
bifoliate
one leaf per node
ALTERNATE
two leaves opposite at one node
OPPOSITE
one leaf per node but spiral arrangement
SPIRAL
three or more leaves around a node
WHORLED
- subclassification of spiral
- exactly 90 degrees difference of leaf
arrangement
DECUSSATE
arrangement of veins on the blade
VENATION
three types NETTED VENATION
pinnately netted
radiately netted
palmately netted
-also called reticulate venation
-branching of the veins
NETTED VENATION
principal veins arise
from the base of the blade
palmately netted
veins arise from the
midrib
pinnately netted
principal veins arise
form the center of the blade
radiately netted
different types
PARALLEL VENATION
parallel to the midrib
palmately parallel
acute angle to the midrib
perpendicular to the midrib
one direction of veins
PARALLEL VENATION
- With cutin
- Flat epidermal cells, with guard cells,
trichomes - High # stomata in lower epidermis
EPIDERMIS
prevents rapid air movement, prevents water
loss from stomata; protection
Trichomes (glandular or non-glandular)
- kidney-shaped, chlorophyllous epidermal cells
GUARD CELLS
- areas where epidermis is depressed into the
leaf - filled w/ trichomes & stomata, at lower surface
of leaf - decrease air movement near stomata to
prevent water from evaporating
STOMATAL CRYPTS
- Ground tissues interior to the leaf epidermis
- Has two parts: palisade parenchyma and
spongy mesophyll
MESOPHYLL
- Uppermost, main photosynthetic tissue
- 1 layer thick, cells are separated, increases
exposure to CO2
PALISADE PARENCHYMA
- Open, loose aerenchyma that permits CO2 to
diffuse rapidly from stomata into all parts of leaf
SPONGY MESOPHYLL
- Between palisade and spongy mesophyll
VASCULAR TISSUE
- important in releasing water from xylem and
loading sugar into phloem
MINOR VEINS
- fibers arranged as a sheath around the
vascular tissue
BUNDLE SHEATHS
- mass of fibers above or below (or both) the
veins
BUNDLE SHEATH EXTENSION
gives rigidity and additional means by
which water moves from the bundle out to the
mesophyll
Fibers
- Serves as transition between the stem and the
leaf blade
PETIOLE
similar to that on the lamina but
often contains fewer stomata and trichomes
Epidermis
may bears two small flaps of tissue at its base
stipules
- vascular bundles which exit the stem and diverge to
the petiole
LEAF TRACES
- detachment area of leaves from the stem;
releases enzymes w/c weaken their walls
ABSCISSION ZONE
- leaf aging due to breakdown of chlorophyll,
sugars and loss of photosynthetic ability
SENESCENCE
- protective scar tissue across wound after leaf
fa
LEAF SCAR
- thick and fleshy, reduced surface-to-volume
ratio - with water storage parenchyma
SUCCULENT LEAVES
have few intercellular spaces
=↓evaporative surface area = transparent
Mesophylls
- pair of succulent leaves
DINTERANTHUS
- spherical succulent leaves
SENECIO
- pair of translucent leaves acting as optical
fiber, allows light to enter, even leaves are
underground
LITHOPS
- Thick sclerenchyma = resistant to animals,
fungi, freezing temp and UV - Very thick cuticle
- Lives for 2 or more years
- Sclerophylls - leaves
SCLEROPHYLLOUS FOLIAGE
- leaf blade curl
- ex. Sundew that has glandular trichomes that
secretes a sticky digestive fluid) or close (ex.
Venus flytrap that has motor cells, margins with
interdigitating teeth and short glands that
secrete digestive fluid)
o other example: Drosera - sundrew
ACTIVE TRAP
Contains cells that can sense contact with other
objects
* side facing the object stop growing, then, the other
side elongate — coil
* no lamina
* Support
TENDRILS
- digest insects and obtain nitrogen for their
amino acid and nucleotides
INSECT TRAPS
- Leaves are sclerophylls
- extremely thick cuticle and the cells of
epidermis have thick walls
LEAVES OF CONIFER
occur in all pines, firs, and
spruces
Needles
Agathis, Araucaria, and
Podocarpus
Scale-like
- incapable of movement
- ex. Pitcher plant that has tubular lamina that
secretes water digestive fluid
PASSIVE TRAP
- One of the most common modification of
leaves - Forms to protect dormant shoot apical
meristems by forming a tight layer around the
stem tip - small and rarely compound
- petiole is either short or absent
- frequently produce a thin layer of corky bark
BUD SCALES
- Produce plantlets
ADVENTITIOUS BUDS / REPRODUCTIVE
LEAVES
- For attraction
- Examples:
o Poinsettia
o Mussaenda
o Bougainvillea
Anthurium – colored spathe
COLORED LEAVES
- Aerenchymatous leaf base for buoyancy and
support
FLOATS
- Supporting leaf bases
- For support
PSEUDOTRUNKS
- display “thigmonasty” or sensitivity to touch for
protection
MOTILE LEAVES
tropic response to
touch
Thigmotropic response –
- For added photosynthesis
EXPANDED LEAF-LIKE PETIOLE OR STIPULE