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

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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

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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