Module 11 - Leaf Flashcards
Other term for leaf
Phyllome
A flat, expanded, green organ that develops laterally at the node and originates from SAM. It has varying structures depending on the environment where it thrives. Its major functions are photosynthesis and transpiration.
Leaf
Parts of the leaf
Blade, Petiole, and Stipule
Parts of the blade
Apex, margin, veins, midrib, base
Arrangement of Veins in a Leaf
Leaf Venation
Two types of venation
Parallel - Veins are pinnately or longitudinally parallel (Monocots)
Netted - Veins are randomly arranged forming a complex network (Dicots)
Leaf Arrangement on a Stem
Leaf Phyllotaxy
Types of leaves
Simple- Single, undivided lamina
Compound- Lamina divided into many leaflets attached to a midvein
Types of compound leaves
Pinnate - Fishbone like
Palmate - Attached at one common point “hand like” kaya palmate gets?
small flaps of photosynthetic tissues that develop covering the branches
Enations
possess a single, well-developed trace of vascular tissue in Lycophytes
Microphylls
possess a single, well-developed trace of vascular tissue in Psilophytes
Prophylls
has more than one vein in its blade and the leaf trace (the vein going into the leaf) is associated with a leaf gap in the stem as seen in Euphyllophytes.
Megaphylls
T/F Enations and microphylls have leaf gaps
False. They do NOT
A leaf gap appears occurs when________
That vascular tissue portion is called a _______.
part of the vascular tissue in the stem is diverted towards the leaf.
Such vascular tissue is called leaf trace.
Nodal anatomy where leaf is
associated with 1 gap at a node
Unilacunar (Parang donut na hiniwaan mo ng onti)
Nodal Anatomy where leaf is associated with 3 gaps at a node
Trilacunar (Parang yung donut hinwaan mo ng onti tas yung hiniwa mo, hiniwa mo pa lalo)
Nodal anatomy where leaf is associated with more than 3 gaps at a node
Multilacunar (Parang hiniwaan mo ng madami yung donut)
Leaves are formed in the _______.
Peripheral zone of the SAM
Initiation of a leaf primordium is associated with an increase in ______.
the frequency of periclinal divisions at the initiation site.
Immediate precursors of the leaf primordia
Founder Cells
Sporangia is protected by a central umbrellalike structure called ______.
Indusium
Each sporangium is surrounded by a strip of inflated of cells called?
Annulus
*Closely associated with the vascular bundles
*Function: conduction of materials between the vascular bundle and the mesophyll.
*With 2 principal types of cells both in direct contact with the endodermis
Transfusion tissue
Types of transfusion tissues
- Transfusion tracheids - thick, lignified secondary walls with circular bordered pits
- Transfusion parenchyma - produce tannin-like substances
3 Axes of the Leaf
Adaxial-Abaxial
Proximodistal
Centrolateral
palisade layer occurs adaxially, spongy layer
occurs abaxially - distribution of stomates is restricted to lower epidermis
vascular bundles are of different sizes and surrounded by
bundle sheaths made of a single layer of parenchyma cells
Dorsiventral Leaf
has one mesophyll type (either palisade or spongy) on adaxial and abaxial sides
stomata distributed on both upper and lower epidermis
in the cross section, vascular bundles are of the same sizes and arranged in a transverse line
vascular bundles have bundle sheath that is 1-2 layers thick
isobilateral leaf
a single epidermis is present around the leaf periphery and encloses the mesophyll
mesophyll may be of 1 or 2 types
stomata distributed on entire circumference of the leaf
vascular bundles are arranged in a ring or a line
Centric Leaf
a specialized structure in C4 plants where the mesophyll cells are clustered around the bundle sheath in a ring-like fashion
number of chloroplasts in the bundle sheath cells is more than in the mesophyll cells
found in C4 plants (i.e. corn)
Kranz Anatomy
Compare c3 vs c4 leaf anatomy
C3 - Palisade distinctly one layer on the adaxial side
C4 - Palisade surrounds the vasc. bundles
Calvin cycle is the dark reaction mechanism in photosynthesis.
C3 Plants
The initial product in the Calvin cycle is _____ defining it as the C3 cycle.
3-phosphoglycerate
C3 plants use the enzyme ______ to directly fix carbon dioxide in the chloroplasts of mesophyll cells.
rubisco
Steps of the C3 Cycle
- Carbon dioxide is fixed into the five-carbon sugar ribulose 1,5-bisphosphate, which is then hydrolyzed into 3-phosphoglycerate.
- In the second step, some 3-phosphoglycerate is reduced to hexose phosphates like glucose 6-phosphate, glucose 1-phosphate, and fructose 6-phosphate.
- The remaining 3-phosphoglycerate is recycled to form ribulose 1,5-phosphate.
Use Hatch-Stack cycle as their reaction mechanism in the dark reaction of photosynthesis
C4 Plants
The first stable compound produced is a four carbon compound ________ which is why the Hatch-Stack cycle is called the C4 cycle.
oxaloacetate
Steps in the C4 Cycle
CO2 fixation occurs in mesophyll cells through the carboxylation of phosphoenol pyruvate, forming a C4 acid (malate/aspartate).
C4 acids are transferred to bundle sheath cells.
Within bundle sheath cells, C4 acids undergo decarboxylation, generating CO2 for the Calvin cycle, leading to carbohydrate synthesis.
The C3 acid (pyruvate or alanine) produced in the decarboxylation step is transported back to mesophyll cells, where it regenerates the CO2 acceptor, phosphoenol pyruvate.
Check the final slide in leaf (Slide 58) for thee summary of c3 vs c4
Yayayeet
