Transport in flowering plants

Name: __________________ Topic: Transport in flowering plants LO:Identifythepositionsandexplainthefunctionsofxylemvessels,phloem(sievetubeelementsand companioncells)in sectionsof a herbaceousdicotyledonous leaf and stem, using the light microscope Concepts Summary NotesNan Hua High School Biology 1

Name: __________________ Topic: Transport in flowering plants ● Function of xylem:Transports water and mineral saltsfrom roots to leaves (nonucleus and no protoplasm)● Function of phloem:Transports sucrose and amino acidsfrom the leaves to thestorage organs and other parts of the plant Xylem vesselConcepts Summary NotesNan Hua High School Biology 2

Name: __________________ Topic: Transport in flowering plants ● Thick,lignifiedcell wall: strengthensthe vesselandpreventsplantfromcollapsing, provides mechanical support.● Narrow, hollow, longlumenwithnocrosswall: Forfastertransportationofwaterand mineral saltsfrom roots to leaves. Phloem ● Sieve tube elements: Allowrapid transport of sucroseand amino acidsdue tolittle protoplasm and a continuous column (no nucleus)● Companion cells:Release energyneeded fortranslocationofsucrose and aminoacidsdue topresence of numerous mitochondria Concepts Summary NotesNan Hua High School Biology 3

Name: __________________ Topic: Transport in flowering plants Functions of xylem and phloem:Similarities:• Xylem and phloem bothtransport substances/materialsto different parts of theplant.• Xylem and phloem bothtransport substances as a solutionto different parts ofthe plant. Differences:• Xylemtransports water and mineral saltswhile phloemtransports sucrose andamino acids.• Xylem transports water and mineral salts inone directionup the plantwhilephloem transports sucrose and amino acids inbothdirections.• Xylem transports water and mineral saltsfrom theroots to the leaveswhilephloem transports sucrose and amino acidsfrom theleaves to other parts of theplant.• Xylem transports water and mineral salts byroot pressure,transpiration pull andcapillary actionwhile phloem transports sucrose andamino acids bypressureflowas a result ofloading sucrose into the phloemviaactive transport. Concepts Summary NotesNan Hua High School Biology 4

Name: __________________ Topic: Transport in flowering plants LO:Relatethestructureandfunctionsofroothairstotheirsurfacearea,andtowater and ion uptake Structure FunctionLong and narrowprotrusion Increases surface areaforfaster absorption of waterand mineral saltsConcentrated cell sapProvides a water potential gradient forwater moleculesto move from higher water potential (soil) into lowerwater potential (cell sap of root hair cell) by osmosis Presence of manymitochondria Torelease energy during aerobic respirationforactivetransport of mineral ionsfrom the soil into the cellsapof the root hair cells Concepts Summary NotesNan Hua High School Biology 5

Name: __________________ Topic: Transport in flowering plants LO:Explainthemovementofwaterbetweenplantcells,andbetweenthemandtheenvironmentintermsofwaterpotential(calculationsonwaterpotentialarenot required) ● Aswatermovesfromxylemvesselintoa plantcell,thecellhashigherwaterpotentialthantheadjacentcellshence net movementof watermoleculesmovesintothenextcellbyosmosis.● Watermovesoutof themesophyllcells andforms a thin film of moisture.● Waterfromthethinfilmofmoistureevaporates to form water vapour.● Concentrationof watervapourinleaf is higherthan that in thesurrounding,thus water vapourdiffusesout of the leaf into thesurroundingsdowna concentrationgradientthroughthe stomatabytranspiration. LO:Outlinethepathwaybywhichwateris transportedfromtherootstotheleaves through the xylem vessels 1. Fromthesoil,byosmosisdueto thewater potential gradient2. Enters theroot hair cells3. Movesfromcell to cell,viaosmosisuntil it reaches thexylem.4. Root pressuremoveswaterfrom cells into and up the xylem.5. Movesupthexyleminthestembycapillaryactionandtranspirationpull.6. In theleaf,watermovesfromcell to cell,via osmosisuntilitreaches themesophyll cells. Concepts Summary NotesNan Hua High School Biology 6

Name: __________________ Topic: Transport in flowering plants ● Rootpressureisthepressureresultingfromtheconstantentryofwaterintotheroots.● Capillaryactionisthetendencyofwatertomoveupnarrowtubesanddependson forces of cohesion and adhesion.● Transpirationpullisthesuctionforcecausedbytranspirationwhichdrawswaterup the xylem. LO:Definethetermtranspirationandexplainthattranspirationisaconsequenceof gaseous exchange in plants Transpirationis thelossof watervapourfromtheaerialpartsoftheplantespeciallythrough thestomata of the leaves. Whenstomataopenin theday, carbondioxidediffusesintotheleaves.Oxygenandwater vapour, which is in higher concentration inthe leaf, willdiffuse outof the leaf. Concepts Summary NotesNan Hua High School Biology 7

Name: __________________ Topic: Transport in flowering plants LO: Describe and explain● theeffectsofvariationofairmovement,temperature,humidityandlight intensity on transpiration rate● how wilting occurs Factors affecting transpiration: ● Air movements (Wind)Windremoveswatervapourandreducestheconcentrationof watervapouraroundtheleaf,makingtheconcentrationgradientsteeper,increasingtherateofdiffusionofwatervapouroutofthestomataoftheleaves. Rateoftranspirationincreases. ● TemperatureThehigherthetemperature, thefasterthewaterevaporatesintointercellularspaces,whichcausesa steeperconcentrationgradient,increasingtherateofdiffusionofwatervapouroutofthestomataoftheleaves. Rateoftranspirationincreases. ● HumidityHumidsurroundinghashigherconcentrationof watervapour, makingtheconcentrationgradientlesssteep,decreasingtherateof diffusionof watervapourout of thestomata of the leaves.Rate of transpirationdecreases. ● Light IntensityStomataopenwiderunderhighlightintensityasguardcellsbecomemoreturgid.Fasterrateof diffusionof watervapouroutof theleaf.Rateof transpirationincreases. Wilting Wiltingoccurswhentherateofwaterlossthroughtranspirationisgreaterthantherateof water absorption. Concepts Summary NotesNan Hua High School Biology 8

Name: __________________ Topic: Transport in flowering plants Ways to measure rate of transpiration Potometer ● Assumption:rateofabsorptionofwaterbytheplantisequaltotherateofwaterloss from the plant.● Aswatermovesintotheplant,theairbubblemovestotheleft.Bymeasuringthedistancemovedbytheairbubbleperunittime,wecanmeasuretherateofwaterlossfrom the leafy shoot. Weight potometer Concepts Summary NotesNan Hua High School Biology 9

Name: __________________ Topic: Transport in flowering plants LO:Definethetermtranslocationasthetransportoffoodinthephloemtissueand illustrate the pro