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Exploring PlantsExploring Plants
Plant Structure & FunctionPlant Structure & Function
TissuesTissues
Vascular tissue form strands that conduct Vascular tissue form strands that conduct water, minerals, & nutrients through a water, minerals, & nutrients through a plantplant
Dermal tissueDermal tissue forms protective outer forms protective outer layer of plantlayer of plant
Ground tissueGround tissue consists of roots, stems, consists of roots, stems, & leaves& leaves
Dermal TissueDermal Tissue Dermal tissue forms a “skin” Dermal tissue forms a “skin” epidermisepidermis Waxy cuticle that prevents water lossWaxy cuticle that prevents water loss Dermal tissue on Dermal tissue on woodywoody stems & roots is made stems & roots is made
up of dead cells up of dead cells corkcork Dermal tissue also functions in gas exchangeDermal tissue also functions in gas exchange
Ground TissueGround Tissue
Makes up inside of most plantsMakes up inside of most plants Ground tissue in leaves, is made up of Ground tissue in leaves, is made up of
chloroplasts (used for photosynthesis)chloroplasts (used for photosynthesis) Ground tissue in stems & roots functions in Ground tissue in stems & roots functions in
storage of water, sugar, & starchstorage of water, sugar, & starch It also surrounds & supports vascular tissueIt also surrounds & supports vascular tissue
Vascular TissueVascular Tissue
- 2 types - 2 types xylem & phloem xylem & phloem
- Both act as plumbing system, carrying - Both act as plumbing system, carrying fluids & dissolved substances through a fluids & dissolved substances through a plantplant
XylemXylem
Thick-walled cells that conduct water & Thick-walled cells that conduct water & mineral nutrients from a plant’s roots, mineral nutrients from a plant’s roots, through stems to its leavesthrough stems to its leaves
Xylem is made up of Xylem is made up of vesselsvessels allow allow water to flow more quicklywater to flow more quickly
PhloemPhloem
Cells that conduct sugars & nutrients Cells that conduct sugars & nutrients throughout plant’s bodythroughout plant’s body
Conducting strands in phloem are called Conducting strands in phloem are called sieve tubessieve tubes
Plant TransportPlant Transport
QuickTime™ and aSorenson Video decompressorare needed to see this picture.
RootsRoots
Plants are anchored down by roots - Plants are anchored down by roots - which absorb water and nutrientswhich absorb water and nutrients
Roots can function in storage of nutrientsRoots can function in storage of nutrients Taproot systemTaproot system large caproot (carrot) large caproot (carrot) Fibrous systemFibrous system many roots many roots
RootsRoots
CortexCortex ground tissue surrounding ground tissue surrounding vascular tissuevascular tissue
Root HairsRoot Hairs epidermal cells just behind epidermal cells just behind root tip - increase surface area to absorb root tip - increase surface area to absorb water and mineralswater and minerals
Root CapRoot Cap mass of cells that covers & mass of cells that covers & protects actively growing root tipprotects actively growing root tip
StemsStems
Shoots of most plants consist of stems & Shoots of most plants consist of stems & leavesleaves
Stems supports the leaves and house the Stems supports the leaves and house the vascular tissuevascular tissue
Leaves are attached to stems at points Leaves are attached to stems at points called nodescalled nodes
Space between 2 nodes Space between 2 nodes internodesinternodes
Parts of PlantParts of Plant
QuickTime™ and aSorenson Video 3 decompressorare needed to see this picture.
Nonwoody StemsNonwoody Stems
Herbaceous plantHerbaceous plant plant with stems that plant with stems that are flexible & usually greenare flexible & usually green
Stems of herbaceous plants contain Stems of herbaceous plants contain bundles of xylem & phloem bundles of xylem & phloem vascular vascular bundlesbundles
Vascular bundles arranged in ringVascular bundles arranged in ring Ground tissue outside ring Ground tissue outside ring cortexcortex Ground tissue inside ring Ground tissue inside ring pithpith
Woody StemsWoody Stems
Trees, shrubs (pines, oaks, roses, & Trees, shrubs (pines, oaks, roses, & hollies) have woody stemshollies) have woody stems
Woody stems are stiff & non-greenWoody stems are stiff & non-green Buds, which form new growth, are found at Buds, which form new growth, are found at
the tips and at the nodes of woody stemsthe tips and at the nodes of woody stems HeartwoodHeartwood wood in the center of a wood in the center of a
mature stem or tree trunkmature stem or tree trunk Xylem that can no longer conduct water, Xylem that can no longer conduct water,
provides supportprovides support
Woody StemsWoody Stems
SapwoodSapwood outside heartwood, conducts outside heartwood, conducts water with vessel cellswater with vessel cells
LeavesLeaves
Primary photosynthetic organ in plantsPrimary photosynthetic organ in plants Most leaves have flattened portion Most leaves have flattened portion bladeblade Blade attaches to stem by a stalk Blade attaches to stem by a stalk petiolepetiole Leaf blade may be divided into 2 or more Leaf blade may be divided into 2 or more
sections sections leafletsleaflets Stomata-Stomata- tiny holes that allow gas exchange tiny holes that allow gas exchange
to occur in plantsto occur in plants
Movement of WaterMovement of Water
TranspirationTranspiration loss of water vapor from a loss of water vapor from a plantplant
More than 90% of water, taken in by roots, More than 90% of water, taken in by roots, is lost by transpirationis lost by transpiration
Guard Cells & TranspirationGuard Cells & Transpiration
Stoma is surrounded by 2 guard cellsStoma is surrounded by 2 guard cells Changes of water pressure in guard cells Changes of water pressure in guard cells
cause the stoma to open or closecause the stoma to open or close Loss of water from guard cells causes Loss of water from guard cells causes
stomata to close, prevents further water stomata to close, prevents further water lossloss
Transpiration:Transpiration: loss of water vapor in plants loss of water vapor in plants