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122 Cards in this Set
- Front
- Back
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Meristem
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Tissue in which cells are actively dividing.
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Types of Apical Meristem types:
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Initials - One remains meristematic.
Derivatives - becomes a new body cell. |
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Apical meristems bring about...
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primary growth - growth in elongation.
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Secondary growth
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Growth in diameter.
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3 overlapping processes for maturation of plant.
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Growth - division and enlargement.
Morphogenesis - development of a shape or a form. Differentiation - How cells differ based on location and gene expression. |
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Primary tissues
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Make up the primary body.
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Tissue
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group of cells working together to perform a certain function.
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Tissues are separated into three tissue systems:
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Dermal
Vascular Ground |
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Permanent tissue
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Tissues, after being produced by meristematic tissue, that has function.
All tissues of the three tissue systems are permanent tissues. |
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Permanent tissues are either...
2 things. |
Simple - all cells performing function are same type.
EX: Ground tissues - Parenchyma, Schlerenchyma, collenchyma Complex - two or more cell types working together to perform function. EX: Vascular, Dermal |
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Simple Tissues:
Composed of three types of cells. |
Schlerenchyma, Collenchyma, Parenchyma
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Parenchyma:
1. Characteristics 2. Location. 3. Function 4. Types |
1. Living, Primary Cell Wall
2. Throughout 3. Metabolism, Storage, Conduction (from cell to cell) 4. Transfer Aerenchyma Chlorenchyma MOST COMMON CELL TYPE IN PLANT BODY |
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Chollenchyma:
1. Characteristics 2. Location 3. Function 4. Types |
1. Elongated, Unevenly thickened primary cell wall, occur in groups
2. Beneath epidermis Ex: Celery strings Leaf petioles 3. Support 4. Angular |
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Sclerenchyma
1. Types 2. Characteristics 3. Location 4. Function |
1. Sclereids, fibers
2. Shape varies, secondary cell walls 3. Throughout (leaves, stems, fruits, seed coats, etc) 4. Protection and support |
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Types of Sclereids
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Brachysclereids
Astrosclereids Columnar Osteosclereids |
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Fibers
1. Characteristics 2. Location 3. Function |
1. Elongated, .2mm to .5 mm
Thick secondary cell wall. Dead. 2. Xylem and Phloem Throughout (ex. - many leaves of monocots) 3. Supports |
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Complex tissues
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Vascular (xylem and phloem)
Dermal (epidermis) |
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Xylem: the principal conducting cells.
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Tracheary elements, composed of two types:
Tracheids and vessel elements. |
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Tracheids: Found in which type of plant?
Have pits? perforations? |
Seedless vascular plants, gymnosperms, primitive angiosperms.
Have pits, do not have perforations. |
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Vessels: Found in which type of plant?
Have pits? Perforation plates? |
Angiosperms
Have both pits and perforation plates. |
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Types of plates
(4) |
Scalariform - perforation plate
Simple - No perforation bars Angular - go at an angle? Truncate - most advanced, cut straight across |
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Which is more advanced, fewer or more bars on perforation plate?
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Fewer bars.
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Phloem:
Types of cells |
Parenchyma
Fibers Sieve elements, composed of a) Sieve cells and b) sieve-tube elements |
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Types of Sieve elements are their corresponding plant types.
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Sieve cells - Seedless vascular plants and gymnosperms
Sieve Tube elements - Angiosperms |
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Sieve Cells
Characteristics |
Primary cell wall
Living Lack a nucleus Pore Size - Sieve Area (group of pores) |
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Albuminous Cell
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Specialized parenchyma cell associated with each sieve cell.
Regulates loading/unloading of sugars into sieve cell. Albuminous cell and associated sieve cells are derived from different mother cells. |
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Callose
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Polysaccharide composed of glucans.
Once cell is injured, releases glucans to block openings. Protective mechanism against insects, continuous loss of sugar. |
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Sieve tube elements
Characteristics |
Common in angiosperms.
Primary cell wall. Living. Lack a nucleus. Pore size - Sieve plate Compound vs. Simple (simple is more advanced) |
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Companion cell
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Associated with each sieve tube elements, they are parenchyma cells, helps with loading/unloading.
Come from the same parent cell. |
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P-protein
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Once called "slime."
Forms a slime plug when the plant is cut. Prevents other plant nutrients from exiting. |
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Epidermis
Characteristics |
Cover primary plant body
Parenchyma cells Outer wall thickest (the one exposed to the environment) Lack chloroplasts (most) Living at maturity (typically) |
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Epidermis
Function |
Protection
Prevents water loss/Absorption Support |
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Specialized Epidermal features
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Cuticle (cutin)
Prevents water loss Mechanical barrier Synthesized by epidermal cells Lacking or ill formed in roots |
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Epicuticular waxes
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Platelets
Rods Granules Hollow |
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Types of epidermal cells:
Ordinary |
Very ordinary?
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Types of epidermal tissues
Guard Cells |
Specialized epidermal cells that occur in pairs.
Poorly developed or lacking cuticle. Can change shape. Contain openings called stomae. How gases are exchanged. Transpiration - loss of water vapor by the plant |
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Transpiration
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Loss of water VAPOR by the plant
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Types of epidermal tissues:
Subsidiary cells |
Specialized epidermal guard cells that occur around guard cells
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Types of epidermal tissues:
Bulliform cells |
enlarged epidermal cells that can collapse or expand. Allows leaf to fold or roll up.
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Types of epidermal tissues:
Trichome |
Provide protection, reduces water loss by reducing amount of air that can blow across leaf.
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Shoot
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Consists of the stem and its leaves
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Primary growth of shoot
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Apical Meristem (most)
Intercalary meristems (few - grasses) |
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Secondary Growth of shoot
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Vascular cambium, cork cambium
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Apical Meristem
1. AKA 2. Characteristics 3. Function |
1. Terminal bud
2. Covered by bud scales - protect apical meristem 3. Responsible for primary growth. Produce leaf primordia. Produce axillary buds. |
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Apical Meristem Histology:
Cyto-Histological Concept |
Majumdar 1942
Gymnosperms |
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Tunica Corpus Concept
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Angiosperms
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Tunica
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Outer most layer of cells
Divide anticlinally Responsible for surface growth Most angiosperms have 3 layers. L1, L2, L3 |
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Corpus
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Spherical body of cells beneath tunica.
Divide in various planes Add bulk to developing stem |
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Two zones of Corpus
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Peripheral/Marginal Zone
-outer layer of corpus -lots of cells divisions Central mother zone -Bulk of corpus -Few cell divisions |
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Peripheral Meristem
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From l1, l2, l3 and peripheral zone of corpus.
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Pith or Rib Meristem
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Area just beneath central mother cell zone
Develops from peripheral zone. |
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Tissue System Development:
Dermal |
L1
Ground L1, L2, L3 Pith Meristem |
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Tissue System Development:
Vascular |
L1, L2, L3
Peripheral Meristem Pith Meristem |
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Elongation of stem
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In active apical meristem, leaf and bud primordia develop very fast so it is difficult to distinguish between nodes and internodes.
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Modes of Internode elongation
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1. Uniform division and elongation throughout
2. Wave of divisions from base upward 3. Divisions restricted to base of internodes (intercalary meristem) |
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Increase in stem thickness during primary growth due to:
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Periclinal cell division
Cell enlargement |
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Xylem (enarch)
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From inside toward outside.
Protoxylem. Metaxylem -cell diameter larger |
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Phloem (exarch)
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Outside to inside.
Protophloem Metaphloem |
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Procambium
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Vascular cambium
Xylem or Phloem |
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Protoxylem
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Matures while stem is still elongating.
Often destroyed after metaxylem matures. Wall thickenings are annular and helical. |
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Protophloem
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First to mature.
Look like elongated parenchyma cell without nuclei. |
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Protoxylem
Development |
Annular
Helical |
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Metaxylem
Development |
Scalariform
Pitted |
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Continuous Vascular Bundle
1. Types of plants, example 2. Regions w/ type of cell |
1.Magnoliids and Primitive Eudicots
Ex. tilia 2. a) Interfascicular region -parenchyma cells b) Vascular cambium (single layer) -parenchyma cells c) Cortex -Parenchyma and Collenchyma d) Pith -Parenchyma e) Ducts or Canals -Mucilage (slimy carbohydrates) |
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Ring of separated vascular bundles
1. In what kind of plants 2. What two types of pith rays |
1.Most Eudicots
2. Open, Closed |
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Open Pith Ray
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Single layer of vascular cambium
Intrafascicular Vascular Cambim - Vascular Tissue Interfascicular Vascular Cambium - Ground Tissue Occurs in plants that have secondary growth. Ex: Sambucus and Medicago |
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Closed Pith Ray
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No vascular cambium
Vascular bundles surrounded by a sheath of sclerenchyma cells. Occurs in plants that lack secondary growth. Ex: Ranunculus and Helianthus. |
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Scattered Vascular Bundles
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Some Eudicots
All Monocots V.B. closed Lack secondary growth EX: Zea |
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Nodal Anatomy:
1. Stem bundle 2. Leaf Trace 3. Branch Trace |
1. vascular bundle of stem
2. vascular tissue that extends from stem bundle out into the leaf 3. vascular tissue that extends from stem bundle out into lateral bud |
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1. Leaf Gap
2. Branch Gap 3. Sympodium |
1. break in vascular tissue above leaf trace.
2. break in vascular tissue above branch trace 3. stem bundle and associated leaf trace |
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Which plants have secondary growth?
Which do not have secondary growth? |
Gymnosperms
Magnoliids Some Eudicots Monocots |
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Most plants that have secondary growth are classified as
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Perennials - plants that live for more than two years.
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What happens to primary tissues when secondary tissue growth occurs?
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Primary tissue is destroyed.
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Secondary growth:
Lateral Meristems (2) |
1. -Vascular Cambium
-Secondary xylem -secondary phloem -vascular rays 2. Cork cambium Periderm - replaces epidermis when destroyed. |
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Intrafascicular
Interfascicular |
From vascular tissue
From ground tissue |
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Planes of cell division
1. Periclinal 2. Anticlinal |
1. Parallel to surface
2. perpendicular to surface |
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Fusiform Initials
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Vertically elongated
Gives rise to vascular tissues: 1. Vessels or tracheids 2. Sieve cell or sieve tube elements 3. Parenchyma 4. Fibers |
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Ray Initials
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Horizontally elongated
Gives rise to vascular rays Parenchyma Secondary xylem rays Secondary phloem rays |
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Functions of Vascular Rays:
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1. Lateral Transport. Sucrose symplastically (across plasma membrane to living part of cell to next cell)
Water apoplastically (along/between cells, does not cross plasma membrane) 2. Storage tissue -Starch -Lipids |
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Vascular Ray Classification
*Seen in tangential section (face view) 1. Uniseriate 2. Biseriate 3. Multiseriate |
1. One cell layer wide
2. Two cell layers wide 3. 3 or more cell layers wide |
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Secondary Phloem
Phloem transport, young/old |
Functional phloem - younger secondary phloem involved in transport
Non functional phloem - no longer involved in transport |
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Secondary Xylem
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Wood of tree
Types of Section Cuts 1. Transverse section (longitudinal) 2. radial (radius of tree) 3. tangential (face view of radial section) |
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Growth rings
1. What do they do 2. Spring wood 3. Summer wood 4. Fall wood |
1. Tell age of tree in years, esp in temperate zones
2. Springwood - large vessels, lots of transport to make leaves, take up more water 3. Summer wood - leaves have been produced cell diameter decreases 4. Fall wood - cell diameter continues to decrease, becomes dormant |
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Ring Porous wood
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Vessles in spring wood very large
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Diffuse porous -
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vessels tend to be uniform in diameter throughout growth ring (though there are more present during spring, summer)
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Non-stoned and stoned wood:
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Non-stoned - overlaps of end walls, cells end at different places, stronger
Stoned wood: cells tend to occur in groups, ending at same places. Weak points. |
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Heartwood
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Often darker portion in center. Older secondary xylem, no longer involved in transport.
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Sapwood
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lighter in color.
Younger secondary xylem, actively involved in transport |
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How sapwood changes into heartwood
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Changes occur before death in living cells.
1. food reserves removed 2. oils, gums, resins formed 3. Tyloses form (in many species) -balloon like outgrowth from ray parynchyma cells into vessels. -growth through pits of vessel -Consist of plysaccharides and pectin -Line inner walls of heartwood |
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Softwood
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A longitudinal tracheid. Thicker, elongated.
3-5 mm long. Writing paper and brown bags. |
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Hardwood
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B. vessel (early wood) - short, wide
D. Vessel (late wood) - short, narrow C. Fiber (1-2 mm long - very narrow, elongated E. Tracheid - a little bit longer and narrower than vessels -kodak paper, toilet paper, napkins, kleenex |
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Knots
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Where a lateral branch has been covered by growth rings
Types: Tight Loose |
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Suberin
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fatty material that lines wall of phellum cells
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Cork Cambium
Origin |
In stems, comes from one of the outer layers of cortex.
In roots, from pericycle. |
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Phellum
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Cork. Results from division of Cork Cambium, to the outside. (dead, suberin)
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Phelloderm
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Formed from division of Cork Cambium, to the inside. Living at maturity.
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Periderm
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Replaces the epidermis as protective covering. Consists of phellum, phellogen, phelloderm.
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Lenticel
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opening in periderm for gas exchange.
Formed by cells growing faster than other cells, creates a break in the periderm. |
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What does bark consist of?
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Periderm
Secondary phloem |
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Leaves
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Primary plant organ produced by a primary meristem
Leaves occur on current year's growth only True leaves are Megaphylls |
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Leaf Development
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Clonal analysis
Marker cells Chimeral Meristems - Apical meristem injected with marker cells Leaves initiate from a group of cell sin the peripheral meristem. From l1, l2, l3 layers. These cells (5-100 are founder cells) elongate. |
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Grass leaf development
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Marginal meristem encircles the stem. Blade wraps around stem. Sheath-part wraps around
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1.Leaf buttress
2. Leaf primordium 3. marginal meristems |
1. the bump, when a new leaf starts forming.
2. Start to see some symmetry 3. Marginal meristems - cause widening of the leaf. Arise from founder cells. |
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Vascular tissue development
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Major veins develop upward and outward as the midrib develops.
Minor veins develop from tip towards the base. Tip of leaf fully developed first. Primary, Secondary, Tertiary, Quaternary growth - ascending in order, getting smaller and finer. |
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Phyllotaxy
1. Alternate 2. Opposite 3. Whorled |
How leaves are arranged on a stem.
1. One leaf per node. -Helical (45 degrees)- evolved so that each leaf can absorb maximum sunlight -Distichous - (180 degrees) - opposite sides. 2. Decussate - two leaves per node 3. Whorled - 3 or more leaves per node AKA Verticillate |
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What determines phyllotaxis?
1.Classical model. 2. New Model |
1.Hormone inhibitor prevents formation of leaf primordia.
2. Auxin (Indole acetic acid) induces new primordia. These primordia serve as a sink and drain IAA from surrounding cells. |
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Leaf Parts
1. Petiole 2. Lamina 3. Stipule 4. Sessile 5. Sheath 6. Ligule 7. Abaxial 8. Adaxial Leaflet anatomy 9. Petiolule 10. Rachis |
1. Stalk of leaf
2. Blade of leaf 3. Small leaflike structures found at edge of leaf 4. Leaf with no petiole 5.When base of leaf wraps around stem (grasses, etc) 6. Thin membrane, holds sheath onto stem 7. Underside of leaf 8. Upper surface of leaf 9. Stalk of a leaflet. 10. Area of central axis between leaflets |
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Simple Vs Compound leaves - Lamina
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Simple - lamina is one piece.
Compound - Lamina is broken down into small units aka leaflets. |
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Types of Compound Leaves:
Palmately |
Leaflets all originate from common point like palm of hand.
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Types of compound leaves:
Pinnately compound |
Like pinnae of a feather. Axis with radiating leaflets.
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Types of Compound Leaves
Bi-pinnately compound (A form of pinnately compound) |
Secondary leaflet
Secondary Petiolule Rachilla - Secondary Rachis |
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Leaf Anatomy:
Tissue Systems |
Dermal - Epidermis
Ground - Mesophyll, Bundle Sheath Vascular - Xylem, Phloem |
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Epidermis:
1. Parenchyma cell characteristics 2. Functions |
1. Living at maturity (normally)
Xerophyes (secondary c.w. and dead) Outer wall thickest Lack chloroplasts 2. Prevent water loss Protection (mechanical and chemical) Support |
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Specialized epidermal features
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Cuticle (made of cutin)
Epicuticular waxes Trichomes Bulliform cells Guard cells |
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Guard cells
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specialized epidermal cells that occur in pairs. Has opening called stoma. Stoma is only opening in epidermis. Allows gas exchange of co2 and O2. Allows for transpiration.
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Remiform guard cells
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Kidney shaped. Eudicots.
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Ostidform guard cells
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Bone shaped. Monocots.
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Subsidiary cells
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Morphologically distinct epidermal cells immediately surrounding guard cells.
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Anomocytic cells
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Subsidiary cells surrounding the guard cell pair are not morphologically distinct from other epidermal cells
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Stomata location
1. Hypostomatic 2. Amphistomatic 3. Epistomatic 4. Astomatic |
1. Guard cells on lower surface
2. guard cells occur on both upper and lower surface 3. Guard cells occur on upper surface. Leaves that float on surface of water. 4. No guard cells. For leaves that are submerged. |
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Guard cell position
1. Above 2. Equal 3. Sunken 4. Stomata crypt |
1. hydrophytes
2. mesophytes 3. Xerophytes 4. sunken pit with hairs, guard cells tucked away in pit. |
