plant structures roots, stems, and leaves
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Plant Structures Roots, Stems, and Leaves. Chapter 23. 23-1 Specialized Tissues in Plants. Plants are as successful if not more successful than animals Seed plants have three main structures: Roots Stems Leaves Linked together by various means. 23-1 Specialized Tissues in Plants. Roots - PowerPoint PPT PresentationTRANSCRIPT
Plant StructuresPlant StructuresRoots, Stems, and LeavesRoots, Stems, and Leaves
Chapter 23Chapter 23
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants Plants are as successful Plants are as successful
if not more successful if not more successful than animalsthan animals
Seed plants have three Seed plants have three main structures:main structures: RootsRoots StemsStems LeavesLeaves
Linked together by Linked together by various meansvarious means
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants RootsRoots
Absorbs water and Absorbs water and nutrientsnutrients
Anchor plant to the Anchor plant to the groundground
Hold soil in place and Hold soil in place and prevent erosionprevent erosion
Protect from soil bacteriaProtect from soil bacteria Transport water and Transport water and
nutrientsnutrients Provide upright supportProvide upright support
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants StemsStems
Support for the plant Support for the plant bodybody
Carries nutrients Carries nutrients throughout plantthroughout plant
Defense system to Defense system to protect against predators protect against predators and infectionand infection
Few millimeters to 100 Few millimeters to 100 metersmeters
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants LeavesLeaves
Main photosynthetic Main photosynthetic systemssystems
Suseptable to extreme Suseptable to extreme dryingdrying
Sight of oxygen/carbon Sight of oxygen/carbon dioxide intake and dioxide intake and releaserelease
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants Plant tissue Plant tissue
systemssystems Exist within the Exist within the
root, stems, and root, stems, and leavesleaves Dermal tissueDermal tissue Vascular tissueVascular tissue Ground tissueGround tissue
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants Dermal TissueDermal Tissue
Outer covering Outer covering Single layer of cellsSingle layer of cells CuticleCuticle – waxy coating – waxy coating
TrichomesTrichomes – – Spiny Spiny projections on the leafprojections on the leaf
Roots have dermal tissueRoots have dermal tissue Root hairsRoot hairs
Guard CellsGuard Cells
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants Vascular TissueVascular Tissue
Transport SystemTransport System SubsystemsSubsystems
XylemXylem PhloemPhloem
Subsystems are used to carry fluids Subsystems are used to carry fluids throughout plantthroughout plant
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants XylemXylem
Two typesTwo types Seed plantsSeed plants AngiospermsAngiosperms
Tracheid Tracheid – long narrow – long narrow cellscells
Walls are connected to Walls are connected to neighboring cellsneighboring cells
Will eventually dieWill eventually die Vessel ElementVessel Element – wider – wider
that trachiedsthat trachieds
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants PhloemPhloem
Sieve Tube ElementsSieve Tube Elements Cells arranged end to endCells arranged end to end Pump sugars and other foodsPump sugars and other foods
Companion CellsCompanion Cells Surround sieve tube elementsSurround sieve tube elements Support phloem cellsSupport phloem cells
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants Ground TissueGround Tissue
Cells between dermal Cells between dermal and vascular tissueand vascular tissue
ParenchymaParenchyma Thin cell walls, large Thin cell walls, large
vacuoulesvacuoules CollenchymaCollenchyma
Strong, flexible cell wallsStrong, flexible cell walls SclerenchymaSclerenchyma
Extremely thick, rigid cell Extremely thick, rigid cell wallswalls
23-1 Specialized Tissues in Plants23-1 Specialized Tissues in Plants Plant GrowthPlant Growth
MeristemsMeristems – tissues – tissues responsible for growth responsible for growth
Undifferentiated cellsUndifferentiated cells Apical MeristemApical Meristem
Produce growth increased Produce growth increased lengthlength
DifferentiationDifferentiation Cells will assume roles in Cells will assume roles in
the plantthe plant Flower DevelopmentFlower Development
Starts in the meristemStarts in the meristem
23-2 Roots23-2 Roots
Types of RootsTypes of Roots TaprootsTaproots
Found in dicotsFound in dicots Long, thick rootLong, thick root Hickory and oak treesHickory and oak trees
Fibrous rootsFibrous roots Found in monocotsFound in monocots No single root larger than any otherNo single root larger than any other Many thin rootsMany thin roots
23-2 Roots23-2 Roots Root StructureRoot Structure
Outside layerOutside layer EpidermisEpidermis
Root hairsRoot hairs CortexCortex
Central cylinder – Central cylinder – vascular systemvascular system
Root Cap – cellular Root Cap – cellular productionproduction
Key role in Key role in water/mineral transportwater/mineral transport
23-2 Roots23-2 Roots Root FunctionsRoot Functions
Anchor plantAnchor plant Absorb waterAbsorb water Absorb nutrientsAbsorb nutrients
23-2 Roots23-2 Roots Plant Nutrient UptakePlant Nutrient Uptake
Soil type determines Soil type determines plant typeplant type
Plant requirementsPlant requirements Oxygen, COOxygen, CO2 2 NitrogenNitrogen PhosphorusPhosphorus PostassiumPostassium MagnesiumMagnesium CalciumCalcium Trace elementsTrace elements
23-2 Roots23-2 Roots Active Transport in Active Transport in
PlantsPlants Root hairs use ATP Root hairs use ATP
Pump minerals from soilPump minerals from soil Causes water molecules to Causes water molecules to
follow by osmosisfollow by osmosis Vascular CylinderVascular Cylinder
Casparian Strip – water Casparian Strip – water retentionretention
Root PressureRoot Pressure Forces water up into the Forces water up into the
plantplant
23-3 Stems23-3 Stems Stem StructureStem Structure
Produce leaves, Produce leaves, branches, and flowersbranches, and flowers
Hold leaves upHold leaves up Transport substance Transport substance
between roots and leavesbetween roots and leaves Essential part of Essential part of
transport systemtransport system Function in storage and Function in storage and
photosynthesisphotosynthesis
23-3 Stems23-3 Stems Xylem and phloem – major Xylem and phloem – major
tubule systemstubule systems Transport water and nutrientsTransport water and nutrients
Composed of three tissue Composed of three tissue layerslayers
Contain Contain nodesnodes – attachment – attachment for leaves for leaves
InternodesInternodes – regions – regions between the nodesbetween the nodes
BudsBuds – undeveloped tissue – undeveloped tissue
23-3 Stems23-3 Stems Stem TypesStem Types
MonocotMonocot – vascular – vascular bundles are scattered bundles are scattered throughoutthroughout
Distinct epidermisDistinct epidermis DicotDicot – vascular tissue – vascular tissue
arranged in a cylinderarranged in a cylinder PithPith – parenchyma cells – parenchyma cells
inside the ringinside the ring
23-3 Stems23-3 Stems Stem GrowthStem Growth
Primary growth – new Primary growth – new cells produced at the root cells produced at the root tips and shootstips and shoots
Increases the lengthIncreases the length Secondary growth – Secondary growth –
increase in stem widthincrease in stem width Vascular cambium – Vascular cambium –
produces tissue and produces tissue and increases thicknessincreases thickness
Cork cambium – produces Cork cambium – produces outer covering of stemsouter covering of stems
23-3 Stems23-3 Stems Formation of Vascular Formation of Vascular
CambiumCambium Xylem and phloem Xylem and phloem
bundles present intiallybundles present intially Secondary growth Secondary growth
initiates production of a initiates production of a thin layerthin layer
The vascular cambium The vascular cambium dividesdivides
Produces new xylem and Produces new xylem and phloemphloem
23-3 Stems23-3 Stems Formation of woodFormation of wood
Wood – layers of exlemWood – layers of exlem Produced year after yearProduced year after year Results from the older xylem not conducting water – Results from the older xylem not conducting water – heartwoodheartwood Becomes darker with ageBecomes darker with age SapwoodSapwood – surrounds heartwood – surrounds heartwood
23-3 Roots23-3 Roots Formation of BarkFormation of Bark
All the tissues outside All the tissues outside the vascular cambiumthe vascular cambium
Consists of outermost Consists of outermost layers of dead corklayers of dead cork
Water proofWater proof
23-4 Leaves23-4 Leaves Main sight of Main sight of
photosynthesisphotosynthesis Consist of:Consist of:
Blade – thin flattened Blade – thin flattened sectionsection
Petiole – stalk that Petiole – stalk that attaches stem to bladeattaches stem to blade
Covered by epidermis Covered by epidermis and cuticleand cuticle Create water proof Create water proof
barrierbarrier
23-4 Leaves23-4 Leaves Leaf FunctionsLeaf Functions
Photosynthesis – occurs Photosynthesis – occurs in the mesophyllin the mesophyll
Palisade mesophyll – Palisade mesophyll – absorb lightabsorb light
Spongy mesophyll – Spongy mesophyll – beneath palisede levelbeneath palisede level
Stomata – pores in the Stomata – pores in the underside of the leafunderside of the leaf
Guard CellsGuard Cells – Surround – Surround the stomatathe stomata
23-4 Leaves23-4 Leaves TranspirationTranspiration
Loss of water through its leavesLoss of water through its leaves Replaced by water drawn into the leafReplaced by water drawn into the leaf
23-4 Leaves23-4 Leaves Gas ExchangeGas Exchange
Take in COTake in CO2 2 and release and release OO22
Can also do the opposite Can also do the opposite – How?– How?
Gas exchange takes place Gas exchange takes place at the stomataat the stomata
Not open all the timeNot open all the time Stomata is controlled by Stomata is controlled by
water pressure in guard water pressure in guard cellscells
23-5 Transport in Plants23-5 Transport in Plants Water TransportWater Transport
Active transport and root Active transport and root pressurepressure
Cause water to move from Cause water to move from soil to rootssoil to roots
Capillary actionCapillary action Combined with active Combined with active
transport and root transport and root pressure, moves materials pressure, moves materials throughout the plantthroughout the plant
23-5 Transport in Plants23-5 Transport in Plants Capillary TransportCapillary Transport
Capillary transport Capillary transport results from both results from both cohesive and adhesive cohesive and adhesive forcesforces
Water molecules Water molecules attracted to one anotherattracted to one another
Water is also attracted to Water is also attracted to the xylem tubes in the the xylem tubes in the plantplant
Causes water to move Causes water to move from roots to the stem from roots to the stem and upwardand upward
23-5 Transport in Plants23-5 Transport in Plants TranspirationTranspiration
Evaporation is the major Evaporation is the major moving forcemoving force
As water is lost, osmotic As water is lost, osmotic pressure moves water out pressure moves water out of vascular tissueof vascular tissue
This pulls water up from This pulls water up from the stem to the leavesthe stem to the leaves
Affected by heat, Affected by heat, humidity, and windhumidity, and wind
23-5 Transport in Plants23-5 Transport in Plants Controlling Controlling
TranspirationTranspiration Open the stomata – Open the stomata –
increase water lossincrease water loss Close the stomata – Close the stomata –
decrease water lossdecrease water loss
23-5 Transport in Plants23-5 Transport in Plants Transpiration and Transpiration and
WiltingWilting Osmotic pressure – Osmotic pressure –
keeps plants semi-rigidkeeps plants semi-rigid Wilting is a result of Wilting is a result of
high transpiration rateshigh transpiration rates Loss of water causes a Loss of water causes a
drop in osmotic pressuredrop in osmotic pressure Loss of rigidityLoss of rigidity Conserves waterConserves water
23-5 Transport in Plants23-5 Transport in Plants Nutrient TransportNutrient Transport
Most nutrients are Most nutrients are pushedpushed through plant through plant
Nutrient movement takes Nutrient movement takes place in phloemplace in phloem
Source to SinkSource to Sink Source – any cell that Source – any cell that
produces sugarsproduces sugars Sink – any cell where Sink – any cell where
sugars are usedsugars are used Pressure-flow Pressure-flow
HypothesisHypothesis