chapter focus u plant structure and growth u warning – many terms or vocabulary words u warning...
TRANSCRIPT
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Chapter focusPlant structure and growthWarning many terms or vocabulary wordsWarning many diagramsFocus structure, function, located next to .
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Question ?What heading can be given to the following groups of words?
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---------Lettuce PeasBeans----------RhubarbApplesOranges
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Question ?What is a vegetable?What is a fruit?
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VegetablesLettuceRhubarb
FruitsPeasBeansApplesOranges
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PointPlants have organs too, just like animals.Asexual organs (vegetables)Sexual organs (fruits)
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Asexual Organs1. Stem2. Leaf3. Root
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StemThe main body of the portion above ground of a tree, shrub or herb.The ascending plant axis.
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Stem FunctionsSupport of other plant organs.Ps.Storage (water and food).
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LeafLateral outgrowths of the stem axis.Primary photosynthetic organs.Function:PhotosynthesisStorage
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RootThe descending axis of a plant, normally below ground.Functions:Anchorage.Absorption of water and minerals.Storage.
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Sexual Organs1. Flowers2. Fruits3. Seeds
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FlowersModified leaves grouped together on a stem.Sexual reproductive organs.Function:Sexual Reproduction
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FruitA mature ovary, sometimes including other floral parts.Function:Seed dispersalSeed protection
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SeedMature ovule containing the embryo and nutrient tissues.Function:Dispersal unit in sexual reproduction.
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Plant Cell TypesDifferentiated by the type and thickness of the cell wall.1. Parenchyma (soft tissue)2. Collenchyma (glue tissue)3. Sclerenchyma (hard tissue)
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Parenchyma CellsPrimary wall only.Thin cell wall.Alive when mature, typical" plant cell.
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FunctionsPsStorage"Filler" cellsCell division (mitosis)
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CollenchymaPrimary wall only.Wall is thickened, especially in the corners.Alive when mature.
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FunctionSupport of non-woody plant parts.Ex: veins, stems.
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SclerenchymaSecondary wall present.Wall strengthened with lignin.Dead when mature.
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Sclerenchyma Types1. Fibers2. Sclereids3. Tracheids4. Vessel Elements
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FibersElongated thin cells used for support.Ex: Hemp fibers
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SclereidsUsed for hard dense areas and support.Ex: Nut shells, seed coats
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TracheidsSpindle - shaped cells with pits in the cell walls.Used for water transportation.VesselFiber
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Vessel ElementsWide stocky cells with pits in the side walls; lack end walls.Used for water transportation.
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Plant TissuesCan be named by several methods:Ex: Cell Location Cell Origin Cell Function
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PointThe same cell can have several tissue names depending on the criteria for naming.
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Main Tissue Systems1. Dermal2. Vascular3. Ground
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Dermal TissueEpidermis or "skin" of the plant.Often has a cuticle, a waxy coating to prevent water loss.Functions:Prevent water loss.Water absorption (root hairs).
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Vascular TissueMade of Xylem and Phloem.Functions:Transport and supportXylem - WaterPhloem - Food
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Xylem
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Phloem
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PhloemSieve Cell alive when functioning, but lacks a nucleus.Companion Cell alive, controls itself and the sieve cell.
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Ground TissueTissue between the dermal and the vascular tissues.Functions:"Filler" tissuePsstoragesupport
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Question ?How does plant growth and animal growth differ ?
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AnimalsWhole organism increases in size.Determinant Growth: grow to a certain size, then stop.
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PlantsGrowth in specialized areas only.Indeterminant Growth: grow as long as they live because the specialized areas remain embryonic.
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Plant MeristemsPerpetual embryonic regions.Zones for cell division.
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Meristem Types1. Apical growth in length. Primary growth.2. Lateral/Cambiums growth in diameter. Secondary growth.
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CommentSome tissues like Xylem may be Primary or Secondary depending on which meristem produced the cell.Ex:Primary xylemSecondary xylem
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Apical Meristem Types1. RAM Root Apical Meristem: primary growth of roots.2. SAM Shoot Apical Meristem: primary growth of shoots.
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RAMLocated at the tip of each growing root.Protected from the soil by the Root Cap.RAM
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Root CapProtects RAM.Secrets a polysaccharide lubricant for root growth.
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Primary Root Zones1. Cell Division - cells small and embryonic.2. Cell Elongation - cells elongate and start to mature.3. Cell Differentiation - cells mature into final cell types.
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Root HairsExtensions of the epidermis to increase surface area for water absorption.Not a true tissue.Comment - root hairs are very delicate and must be continually replaced.
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Root Hairs
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RAM - Primary Tissues1. Protoderm2. Procambium3. Ground Meristem
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ProtodermWill mature into the epidermis and root hairs.
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Procambium SteleMatures into the vascular tissues of the stele:XylemPhloemPericycle site of branch roots
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Ground MeristemMatures into the ground tissues:Cortex storage tissueEndodermis second skin around the stele that controls the movement of materials into the stele.
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EpidermisCortexStele
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PericycleXylemPhloemEndodermis
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Branch RootsOriginate from the pericycle.Burst their way to the outside.
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Root TypesTaproot - one main root.Ex: carrotFibrous Roots - many small roots of equal size.Ex: grass roots
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Adventitious RootsRoots that develop from other plant parts.Ex: roots on stem cuttings climbing roots
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SAM Produces1. Protoderm2. Procambium3. Ground MeristemComment these tissues mature into the same things as seen in RAM.
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SAM DifferencesNo "root" cap.Produces leaves as stem out-growths at the nodes.Has buds.
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BudsApical Meristems protected by modified leaves or bud scales.Axillary Buds
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Branch StemsDevelop from axillary meristems or axillary buds."External" development.
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Modified Stems1. Rhizomes2. Stolons3. Tubers4. Tendrils
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RhizomeAn elongated underground horizontal stem.Ex: Iris, many grasses
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StolonAn elongated above-ground horizontal stem.Ex: Strawberries Airplane Plant
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TuberA much-enlarged, short, fleshy underground stem tip.Ex: Dahlia, Potato
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TendrilA slender coiling stem.Ex: Clematis and other climbing vines.
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LeavesStem outgrowths for Ps.Leaf Morphology:1. Gross2. Fine
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Gross MorphologyBlade - the flattened portion of a leaf.Petiole - stalk of a leaf.
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BladePetioleAxillary Buds
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Blade/Leaf TypesSimple - 1 blade.Compound - Several blades.
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Nodes and InternodesNode - stem area where a leaf and bud are attached.Internode - stem area between nodes.
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NodesInternode}
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Fine MorphologyThe tissues within a leaf.1. Upper Epidermis2. Mesophyll3. Lower Epidermis4. Veins
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Upper EpidermisCuticle present.Usually 1 cell layer thick.Cells w/o chloroplasts .Function: protects the mesophyll.
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Mesophyll1. Palisade upright cells.2. Spongy loosely organized cells with air spaces.Function: major sites for Ps.EpidermisEpidermis
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Lower EpidermisCuticle present.Usually 1 cell layer.Cells w/o chloroplasts.Stomata present for gas exchange.
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Stomata (mouth)Regulated by Guard Cells which have chloroplasts.
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Vein StructureXylem: dorsalPhloem: ventralOften surrounded by bundle sheath cells for support.
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XylemPhloemBundle Sheath CellsCollenchyma
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HomeworkRead Chapter 35, 37No lab broadcast 3/27Chapter 35 Fri. 3/28
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Leaf Modifications1. Tendrils: for support Ex: Peas2. Bulbs: for food storage Ex: Onion3. Insect Catching Ex: Carnivorous Plants4. Flowers: thought to be modified leaves.
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TendrilsSpinesSucculent LeavesBractsOther Modifications of Leaves
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Stem Vascular TissueDicots vascular bundles join together to make a ring. Often have secondary growth.Monocots vascular bundles are scattered. No true secondary growth.
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Secondary GrowthGrowth in diameter.Growth from lateral meristems or cambiums.
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Cambium Types1. Vascular produces xylem and phloem.2. Cork produces cork.
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Vascular CambiumLocation: between primary xylem and phloem.Produces: secondary xylem and phloem.
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FibersPhloemVascular CambiumXylemFibers
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Vascular Cambium: Cell MaturationInternal xylemExternal phloemThe VC pushes the xylem and phloem apart from each other.
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ResultNewest xylem is next to the cambium. Oldest xylem is in the center of stem.
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ResultNewest phloem is next to cambium.Oldest phloem is under the epidermis.
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ResultXylem accumulates over time. Phloem is destroyed by the outward growth and must be replaced yearly.
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Cork CambiumLocation: Cortex (external to the VC).Produces: CorkComment commercial cork is harvested from a Cork Oak.
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Cork CellsProduced "outwardly" only.Covered with suberin and are dead when mature.Function insulation and protection.
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Vascular CambiumCork CambiumPhloem XylemFibersCortexEpidermis
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BarkAll tissues external to the VC.Includes:Phloem (1 degree and 2 degree)Cork CortexEpidermisFiber cells
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WoodXylem tissue of a dicot stem.Comment monocots dont have VC and technically dont produce true wood.
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Xylem GrowthSpringwood - Large cells Rapid growthSummerwood - Small cells Slow growth
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Annual RingsFormed by the growth difference between springwood and summerwood.Usually one produced per year.
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CommentRing size varies by climate and growing conditions.Rings can be used to date wooden structures.
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Summer WoodSpring WoodOne Years Growth
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AngiospermsDivided into two main types:1. Dicotyledons or Dicots2. Monocotyledons or MonocotsCotyledons = seed leaves
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Monocots vs. Dicots1. Seeds and embryos2. Leaves3. Stems4. Roots5. Flowers
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Seeds and EmbryosDicots - no endosperm. - 2 cotyledons.Monocots - endosperm - 1 cotyledon
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LeavesDicots netted veins.Monocots - parallel veins.
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StemsDicots - ring pattern - vascular cambiumMonocots - scattered pattern - no vascular cambium
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RootsDicots - taproot. - xylem centermost tissue.Monocots - fibrous roots. - pith centermost tissue.
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FlowersDicots parts in 4's or 5's.Monocots parts in 3's.
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SummaryKnow the main organs of plants and their functions.Know the main cell types or tissues in plants and their functions.
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SummaryKnow the structural organization of stems, roots, and leaves.Know the differences between dicots and monocots.