Looks like no one added any tags here yet for you.
store water
succulent modified stem function
for climbing
tendrils
to deter herbivores + reduce water loss
function of thorns/spikes
- Blade or lamina
- Apex, Base, Margin
- Veins (vascular bundles)
- Petiole (Stalk)
- Stipules
leaves external anatomy
expanded petiole in monocots bc they have no stalk
leaf sheath definition
phyllotaxy
arrangement of leaves on a stem
opposite
phyllotaxy if 2 leaves on a node
alternate
phyllotaxy if 1 leaf on a node
whorled
phyllotaxy if multiple leaves on a node
basal
phyllotaxy if leaves are nasa baba
Decussate
special type of opposite phyllotaxy; 2 pairs of leaves 90 degrees to each other
undivided blade with a single axillary bud at the base of its petiole
simple leaf definition
pinnately-compound leaves
- leaflets in pairs
- rachis
extension of the petiole in pinnately-compound leaves
rachis definition
palmately-compound leaves
no rachis, leaflets attached at the same point at the end of the petiole
always at base of leaf (above the petiole)
location of axillary bud
only primary growth
type of growth of leaves
arrangement of tissues dictated by the physical environment (e.g. water availability, light intensity, ecological niche and herbivores)
how are leaves the most plastic/variable organs
1. Epidermis
2. Mesophyll
3. Vascular tissues
internal parts of leaf lamina
adaxial
closer to the internode above it; faces upward
Abaxial
faces downward
xeromorphic plants; modified structure when water is limited
saan common ang multiple epidermis
if all true epi, origin is protoderm
if may part of hypodermis (part of mesophyll) galing ground meristem
origins of multiple epidermis
- cuticle (hydrophobic)
- stomata (bc no intercellular spaces)
- trichomes (deters herbivory + reduces water loss)
features/parts of epidermis
parenchymatous ground tissues specialized for photosynthesis
mesophyll definition
Chlorenchyma
Parenchyma cells containing chloroplasts
Elongated; rod shaped in xs
Arranged in rows
Immediately below the epidermis (uni- or multi-seriate)
On adaxial surface
palisade mesophyll definition
Presence of lobes
Larger volume of intercellular spaces
spongy mesophyll definition
- Majority of the chloroplasts are found in palisade
- intercellular spaces for rapid gas exchange
- external (epidermal) and internal (mesophyll) surface area
reasons for photosynthetic efficiency
Dorsiventral or bifacial
Type of mesophyll in which the palisade is on one side and spongy mesophyll is on the other side
Isobilateral or isolateral or unifacial
Palisade present on both sides (Ficus)
Eudicot leaf - palisade developed
Monocot leaf - uniform
monocot vs eudicot mesophyll
Convergent or uniform
Mesophyll cells look the same; no distinct palisade and spongy parenchyma (Pinus)
- Vascular bundles or + assoc. non vascular tissues that surround it
- Usually have bundle sheath (parenchymatous)
veins definition
monocot
Vascular Bundles of similar dimensions
dicot
have a large central Vascular Bundle called a Midrib
C3 plants (normal photosynthesis)
where are bundle sheaths inconspicuous
C4 plants bc they store CO2 in bundle sheaths where calvin cycle happens
where are bundle sheaths enlarged
leaf - x outer, p inner
stem - x inner, p outer
leaf vs stem xy and phlo
venation
arrangement of veins in a leaf
common to eudicots and some nonflowering plants
where can u find netted venation (pinnately and palmately)
monocots
where can u find parallel venation
- epidermis
- Collenchyma close to the larger veins
- vascular bundles with fibers in monocots
- Sclereids in aqua plants
4 supporting tissues of the leaf
- Epidermis continuous with stem
- Parenchyma contains a few chloroplasts
- collenchyma and sclerenchyma
- Collateral vascular bundle
petiole description: type of ground tissue present? vascular bundle type?
v large vacuole to fold up + reduce water loss
bulliform/motor cells function
- Grow in arid habitats
- Decreased transpiration under conditions of water deficiency
xerophytes definition
- small + narrow leaves to lessen water loss
- Thick walls w cuticle and sclerenchyma
external specializations of xeromorphic plants
- multiseriate epidermis
- stomatal crypts
- abundant trichomes
- tendency to be isobilateral
- Involution of leaves through bulliform cells
5 internal specializations of xeromorphic plants
hide the stomata, invaginations in lower epi + maraming 3chomes
stomatal crypts definition
gymnosperms
examples ng xeromorphic
- consists of tracheids and elongated parenchyma cells
- characteristic of gymnosperms
- passage of water and nutrient substances between the bundle and the mesophyll
Transfusion tissue consists of what and its function
- Thick wall and thick cuticle
- Stomata are sunken and overarched by subsidiary cells
- Hypodermis
- Mesophyll walls have ridge-like invaginations into the cells; contain chloroplasts
- Transfusion tissue
- Endodermis
features of pinus leaves
- Epidermal cell thick walled and thick cuticle
- Stomata are sunken and abaxial surface
- Hypodermis
- Vein surrounded by endodermis
features of cycas leaves
- Reduction of supporting (water supports) and protective tissues
- Decrease vascular tissue esp xylem
- Presence of air chambers for filtration
- very thin cuticle
- Aerenchyma
5 features of hydrophytes
Epistomatic (floating)
hydrophytes stomata
very reduced
hydrophytes root system
- periclinal
- sides of the apex/peripheral zone
- come from apical meristem
leaf initiation
Protrusion in the peripheral zone that will turn into leaf primordia
leaf buttress definition
at sites that are correlated with the phyllotaxis of the shoot
where do leaf primordia arise
Functions of Leaves
blade or lamina
the flattened, green, expanded portion of a leaf
Apex, Base, Margin
Sections of leaf
Veins
The vascular bundles of the leaf traversing because of the thin surface
petiole
The stalk of a leaf, which joins the leaf to a node of the stem.
Stipules
a pair of leaf like appendages at the base of the petiole that protect the developing bud
leaf sheath
the base of a leaf that wraps around the stem; typical in grasses and some other monocots; no stalk and an expanded petiole
phyllotaxy
arrangement of leaves on a stem
blade divided into leaflets
compound leaf defimition
True
Leaflets lack an axillary bud but each compound leaf has a single bud at the base of its petiole (True or False)
Rachis
extension of the petiole in which several leaves are attached
False, above petiole
Axillary bud is always at base of leaf below the petiole (True or False)
True
Leaves generally have primary growth (True or False)
True
The arrangement of tissues is dictated by the physical environment such as water availability, light intensity, ecological niche, and herbivores (True or False)
Epidermis, Mesophyll, Vascular Tissues
Three main components of the leaf lamina
adaxial epidermis
This leaf layer is generally protective and contains trichomes, cuticle, epidermal cells and sometimes stomata. It is closer to the internode above it.
abaxial epidermis
lower epidermis
Protoderm
Origin of true epidermis
Ground Meristem
Origin of hypodermis (a part of mesophyll)
True
Epidermis has cuticle and is devoid of intercellular spaces (True or False)
Stomata
Openings of the epidermis for photosynthesis
Trichomes
Tiny, spike-like projections on some leaves for protection
mesophyll
The ground tissue of a leaf, sandwiched between the upper and lower epidermis and specialized for photosynthesis.
True
Mesophyll is parenchymatous !!!! (True or False)
palisade mesophyll
Layer of tall, column-shaped mesophyll cells just under the upper epidermis of a leaf
spongy mesophyll
Loose tissue beneath the palisade layer of a leaf; has many air spaces between its cells
Chlorenchyma
Parenchyma cells containing chloroplasts that function in photosynthesis
palisade parenchyma
elongated photosynthetic cells; rod shaped in cross section that are arranged in rows
Spongy parenchyma
Presence of lobes and larger volume of intercellular spaces
What are the reasons for increase in photosynthetic efficiency?
Convergent/Uniform
In monocot and gymnosperms, what is the common type of mesophyll?
Veins (Leaf)
Vascular bundles or associated non-vascular tissues that surround it.
Midrib vein
single large vein of the leaf
True
Monocots have similar dimensions for veins (True or False)
bundle sheath
A protective covering around a leaf vein, consisting of one or more cell layers, usually parenchyma.
True
In C3 plants, bundle sheath is inconspicuous (True or False)
C3 plants
A plant that uses the Calvin cycle for the initial steps that incorporate CO2 into organic material, forming a three-carbon compound as the first stable intermediate. (mesophyll)
perform calvin cycle in their bundle sheath
C4 plants differ from C3 and CAM plants in that C4 plants _____.
True, photorespiration
In C4 plants like corn, they have specialized structure called bundle sheath where they store carbon dioxide in which it happens to combat what?
True
Larger bundles usually lack bundle sheath or they have sclerenchymatous sheath (True or False)
parallel venation
a parallel arrangement of veins; typical of the leaves of monocots