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Botany: Bio 1C
Plant Tissue Systems
50
Biology
Undergraduate 1
10/12/2006

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Term
What are the three basic plant organs
Definition
1. Roots
2. Stems
3. Leaves
Term
Root
Definition
-An organ that anchors the vascular plant
-Absorbs minerals and water
-Often stores organic nutrients
-Many plants have modified roots, like adventitious(roots arise above ground from stems and even leaves)
-Taproots: gymnosperms and eudicots
-Fibrous Root: Seedless vascular and monocots
Term
Stems
Definition
-Shoot System
-Nodes: point of leaf attachment
-Internodes: Segments between nodes
-Axillary buds: form new shoots or branches
-Terminal buds: can lead to apical dominance
Term
Shoot and Root System
Definition
[image]
Term
Leaves
Definition
-Blade and petiole -Monocots don't have petioles though -Leaf types: 1. Simple leaf, 2. Compound leaf, 3. Double compound leaf[image]
Term
Primary tissues in stems
Definition
-Parenchyma: photosynthesis, storage and/or secretion
-Collenchyma: Support of young growing parts
-Sclerenchyma: Support of mature plant parts; fiber cells
-Xylem:
-Phloem:
-Epidermis:
Term
Cortex
Definition
- Ground system; Parenchyma tissue
Term
Stele
Definition
-Vascular system; Xylem and Phloem tissues
Term
Ground Tissue
Definition
1. Parenchyma and transfer cells
2. Collenchyma Cells
3. Sclerenchyma, fibers and sclereids
Term
Vascular Tissue
Definition
1. Xylem, tracheids or vessle members, some parenchma cells, fibers and sclereids

2. Phloem, sieve cells or sieve-tube members, specialized parenchyma cells(companion cells), Fibers and Sclereids
Term
Pith
Definition
Internal to Vascular; part of ground tissue
Term
Epidermis
Definition
1. Guard Cells
2. Trichomes: appendages; facilitate absorption or reduce solar radiation; some secrete salts in halophytes
3. Cuticle: cutin and wax; minimize water loss
Term
Parenchyma Cells
Definition
-Alive at maturity
-No secondary walls
-Site of most plant metabolism
-Play a role in wound healing and regeneration
Term
Collenchyma
Definition
-Living at maturity
-No secondary cell walls or lignin
-Provide flexible support to growing parts of plant
Term
Sclerenchyma Cells
Definition
-Thick secondary walls, usually with lignin
-Usually dead at maturity
-Usually specialized for support and strengethening
-Have Sclereids(impart hardness to seed coats and shells of nuts; pear grit)
-Have Fibers(long slender tapered; flax and hemp)
Term
Xylem Cells
Definition
-Dead at maturity
-Tracheids found in all vascular plants because safer due to less specialization(long and thin with tapered ends; lignin for structural support)
-Vessel elements found mainly in angiosperms, but have perforations creates an open system, so less safe(wider, shorter and less tapered; Perforations for more efficient water flow)
Term
Phloem
Definition
-Primary phloem is often destroyed during elongation of the organ
-Principal conducting cells are the sieve elements("with pores")
Term
Sieve-tube members
Definition
-Alive at maturity, but lack nucleus, ribosomes, organelles
-Served by nucleus of adjacent companion cells, which are connected via plasmodesmata
Term
Major meristems
Definition
-In general meristem is a region of perpetual cell division that allows the plant to grow rapidly
-Apical: lenghtens the plant(primary growth); Found in the buds or roots
-Lateral: thickens the plant with bark and wood(secondary growth); Found in stem
Term
Primary growth of a root
Definition
1. Zone of cell division 2. Zone of elongation 3. Zone of maturation [image]
Term
The three primary meristems
Definition
1. Protoderm
2. Ground meristem
3. Procambium
Term
Eudicot vs Monocot Root
Definition
eudicot: Small pericycle around concentrated vascular tissue monocot: Large pericycle [image][image]
Term
Where do the lateral roots arise from?
Definition
Pericycle [image]
Term
Leaf primordia
Definition
The small leaves covering the apical meristem [image]
Term
Eudicot vs Monocot Stems
Definition
-Monocot: Vascular tissue arranged in bundles; ground tissue in center; Bundles spread throughout -Eudicot: Vascular tissue in bundles making a wide circle; ground tissue in center[image][image]
Term
Vascular cambium
Definition
-the interior lateral meristem; produces secondary xylem (to the interior) and phloem (to the exterior)

-Ray initials make cells elongated horizontally; transfer water and nutrients, store starch
Term
Cork Cambium
Definition
-The exterior lateral meristem; produces cork cells to the exterior

-Forms from cortex to fill in gaps as epidermis is tretched and broken by lateral expansion of stem

-Rays maintain connectivity betwen secondary xylem and secondary phloem, allow exchange of nutrients nadwater, store starch and organic nutrients
Term
Wood
Definition
-Secondary xylem; everything on the interior side of the vascular cambium
Term
Bark
Definition
-everything exterior of the vascular cambium, including the secondary phloem and the periderm(cork cambium and cork)

-Living phloem and Periderm

-Heartwood: dead inner woord
-Sapwood: alive outer wood
Term
What makes up a plant's mass?
Definition
1. Water(most of the living plant)
2. Carbon(most of the dry weight)

-Mass from air and water not inorganic nutrients and ions
Term
Diffusion
Definition
-Net movement down a concentration gradient due to the random motion of individual molecules
-Short-distance flow of fluids in plants; cell to cell at the level of tissues and organs
Term
Bulk Flow
Definition
-Movement of water and solutes together due to a pressure gradient
-Long distance transport within xylem and phloem at the level of the whole plant
-Movement driven by pressure
Term
Osmosis
Definition
-Movement of water in or out; Transport of water and solutes by individual cells such as root hairs
-Determines the net water uptake or loss by a cell
-Affected by solute concentration and pressure
Term
Selective Permeability of Membranes
Definition
-Plasma membrane
-Controls the movement of solutes into and out of the cell
Term
Proton Pumps and Plants
Definition
-Creates a hydrogen ion gradient that is a form of potential energy that can be harnessed to do work
-Contributes to a voltage known as a membrance potential
-Plants cells use energy stored in the proton gradient and membrane potential to drive the transport of many different solutes
Term
Cotransport
Definition
-A transport protein couples the passage of one solute to the passage of another
-"coat-tail"effect
-Responsible for uptake of sucrose by plant cells
Term
Water Potential
Definition
-Measurement that combines the effects of solute concentration and pressure
-Determines the direction of water movement
-Water moves from areas of higher potential to lower potential
-Pressure potential created by positive and negative physical pressure on water
-Solute potential created by a higher solute/lower water concentration
Term
Aquaporins
Definition
Transport proteins that facilitate water movement across membrances
Term
Vacuole
Definition
-Major compartment in most mature plant cells
-Large organelle that can occupy 90% of the protoplast's volume
Term
Cytoplasmic Continuum
Definition
-In most plant tissues the cell walls and cytosol are continuous from cell to cell
-Called the Symplast
-The continuum of cytosol connected by plasmodesmata
Term
Apoplast
Definition
-The continuum of cell walls plus extracellular space
-symplast+extracellular space
Term
Routes for Water and Minerals
Definition
-Transmembrane route: Out of one cell, across a cell wall, and into another cell
-Via the Symplast
-Along the Apoplast
Term
Why use bulk flow in long distance transport?
Definition
-Movement of fluid in the xylem and phloem is driven by pressure differences at opposite ends of the xylem vessles and sieve tubes
-Diffusion does not work well over long distances
-Transpiration/negative pressure drives xylem flow
-Hydrostatic pressure in one end of teh sieve tube forces sap in phloem
Term
Mycorrhizae
Definition
-Facilitates the absorprtion of water and minerals from the soil
-Roots and fungi form symbiotic structures consisting of plant roots united with fungal hyphae
Term
Casparian Strip
Definition
-Blocks the apoplastic pathway into the stele
-Waxy;Part of the endodermal wall
-Blocks apoplastic transfer of minerals from the cortex to the vascular cylinder
Term
Cortical Cell
Definition
-Extensive surface area
-Membrances enhance uptake of water and selected minerals
Term
Endodermis
Definition
-Selective sentry
-The innermost layer of cells in the root cortex
-Surrounds the vascular cylinder and functions as the last checkpoint for the selective passage of minerals from the cortex into the vascular tissue
-All material must pass via the symplast
Term
Transpirational Pull on Xylem Sap
Definition
-Transmitted from leaves to roots and even soil
-Facilitated by cohesion of water molecules to one another and adhesion of the hydrophilic vessel walls
-Small diameter of vessels and tracheids increase adhesive surface
Term
Phloem Flow
Definition
-Translocated: organic nutrients/sugars dispersal through the phloem
-The specialized cells involved in this process are either Sieve Tube Members(In angiosperms; with companion cells) or Sieve Cells(In Gymnosperms; with albuminous cells)
-Phloem loading requires active transport(need proton pump)
Term
Phloem sap
Definition
-Aqueous sucrose solution
-Travels from a sugar source to a sugar sink
-Also carries minerals, amino acids, and hormones
-Must be loaded into sieve-tube members before being exposed to sinks
-Many plants move by symplastic ad apoplastic pathways
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