Page 1
Student'sSheet
Printed:15/05/201913:08:11|P4110360
Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
Difficulty
Easy
PreparationTime
10Minutes
ExecutionTime
40Minutes
RecommendedGroupSize
2Students
TranspirationofleaveswithCobra4(ItemNo.:P4110360)
CurricularRelevance
AdditionalRequirements:
Roseorsimilarplant(withthickleaves)
Plasticbag
Knife
AndroidtabletoriPad
PHYWEmeasureApp
ExperimentVariations:
withComputerwithUSBport,Windows
Keywords:
Transpiration,Waterandnutrientstransport,Influenceofwind,Temperature,Humidityandtypeofleaves
Overview
Principle
Thepurposeofplanttranspirationistotransportwaterandnutrientsfromtheplantrootstotheleaves.Inthisexperimentplant
transpirationisinvestigatedbymeansofpressuredecreasemeasurements.Pressuredecreaseisbroughtaboutbyvegetal
dischargefromtheleavesintotheenvironment.Itisthebasisofthecontinuouswatercurrentfromthesoil.Inthisexperiment
comparethetranspirationofleavesundervariousenvironmentalconditions.
AreaofExpertise:
Biology
EducationLevel:
University
Topic:
PlantPhysiology/
Botany
Subtopic:
WaterBalance
Experiment:
Transpirationof
leaveswithCobra4
Page 2
Student'sSheet
Printed:15/05/201913:08:11|P4110360
Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
Fig.1:Experimentset-up
Equipment
ExperimentwithCobra4Wireless/USB-LinkwithAndroidtabletoriPad
Page 3
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Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
PositionNo. Material OrderNo. Quantity
1 Cobra4Wireless/USB-Linkincl.USBcable 12601-10 1
2 Cobra4Sensor-UnitPressure,7barabsolute 12647-00 1
3 HolderforCobra4withsupportrod 12680-00 1
4 Supportbase,variable 02001-00 1
5 Supportrod,stainlesssteel,500mm 02032-00 3
6 Bosshead 02043-00 2
7 Universalclamp 37715-00 1
8 Testtube,200x30mm,sidearm,PN29 36331-00 1
9 Rubbertubing,i.d.6mm 39282-00 1
10 Plasticine,10sticks 03935-03 1
11 Rubberstopper26/32,1hole1,5mm 39258-09 1
12 Beaker,low,BORO3.3,1000ml 46057-00 1
13 digitalmagneticstirrerwithheating,stainlesssteel,280°C,100-1500rpm FHO-
RSM10HS
1
14 Rubberbands,50pieces 03920-00 1
15 Hot/coldairblower,1800W 04030-93 1
16 USBchargerforCobra4Mobile-Link2andWireless/USB-Link 07932-99 1
Additional
material:
AndroidtabletoriPad
PHYWEmeasureApp
Roseorsimilarplant(withthickleaves)
Plasticbag
Knife
Android iPad
ExperimentwithCobra4Wireless/USB-LinkandPC
Page 4
Student'sSheet
Printed:15/05/201913:08:11|P4110360
Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
PositionNo. Material OrderNo. Quantity
1 curricuLABmeasureLAB 14580-61 1
2 Cobra4Wireless/USB-Linkincl.USBcable 12601-10 1
3 Cobra4Sensor-UnitPressure,7barabsolute 12647-00 1
4 HolderforCobra4withsupportrod 12680-00 1
5 Supportbase,variable 02001-00 1
6 Supportrod,stainlesssteel,500mm 02032-00 3
7 Bosshead 02043-00 2
8 Universalclamp 37715-00 1
9 Testtube,200x30mm,sidearm,PN29 36331-00 1
10 Rubbertubing,i.d.6mm 39282-00 1
11 Plasticine,10sticks 03935-03 1
12 Rubberstopper26/32,1hole1,5mm 39258-09 1
13 Beaker,low,BORO3.3,1000ml 46057-00 1
14 digitalmagneticstirrerwithheating,stainlesssteel,280°C,100-1500rpm FHO-
RSM10HS
1
15 Rubberbands,50pieces 03920-00 1
16 Hot/coldairblower,1800W 04030-93 1
17 USBchargerforCobra4Mobile-Link2andWireless/USB-Link 07932-99 1
Additional
material:
ComputerwithUSBport,Windows
Roseorsimilarplant(withthickleaves)
Plasticbag
Knife
Tasks
1. Comparethetranspirationofleavesundervariousenvironmentalconditionsandgeneratepressurecurves.
2. Discussthedifferencesbetweenthedifferentpressurecurves.
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Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
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Set-upandprocedure
Set-up
SetuptheequipmentasinFig.1.
Useoneofthetwosupportrodswhichisattachedtothesupportbasetoholdthetesttube.
AttachtheCobra4Wireless/USB-LinktotheCobra4Sensor-UnitPressuretotheholderontheothersupportrodinsucha
waythattheairintakenozzleoftheSensor-UnitPressureispositionedapprox.2cmhigherthanthehoseconnectorofthe
testtube.
UseashortpieceofhosetoconnecttheairintakenozzleoftheSensor-UnitPressuretothehoseconnectorofthetest
tube.
Fillthetesttubewithwaterandfastentherubberstopperwithoutanyformationofairbubblesinthetesttube.
ConnecttheCobra4Wireless/USB-LinktothetabletinthewirelessWiFimodeafterswitchingiton.
Startthesoftware .TheCobra4measuringdevicewillbeautomaticallydetected.
Selectthemeasurementwindowofyourchoice.Itisbesttochoosethemeasurementwindowwiththe
measurementgraph.
Fig.2:SelectingtheSensor-UnitPressureinthemeasureAPP
Page 6
Student'sSheet
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Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
Procedure
Experiment1
Cutoffasmallleafyshootorasoil-plantjustabovethesoil.Peelfromthelowerpartoftheshootwithaknifeandcutthe
endoffataslant(45°).
Quicklypushtheshootthroughthestopperandsealthestopperwellwithplasticine.
Withoutdelay,removethehosefromtheairintakenozzleoftheSensor-UnitPressure,fitthestopperwithplantonthetest
tube(avoidingairbubbleformationinthetesttube)andfitthehosebackontheSensor-Unit.
Caution!Donotletanywaterpenetrateintothepressuresensorwhiledoingthis!
Startmeasurement(idealrunningtime:atleast100s,butlongerisbetter–measurementwasmadefor1000sinthe
examplegiven).
Taketheinitialandfinalpressuresfromthemeasuredvaluesandcalculatethedifference.
Experiment2a:(PreparationasforExperiment1)
Exposetheplanttoacoldflowofairfromthedryerduringmeasurement.
Experiment2b:
Setthedryertohotairandexposetheplanttothehotflowofairfromthedryerduringmeasurement.
Experiment3:
Bring½litreofwatertoboilingandcollectthesteamthatisgivenoffinaplasticbagforsomeseconds(Caution!Donot
allowtheplasticbagtotouchthehotbeaker!).
Puttheplasticbagovertheplant,closeitwithanelasticbandandstartmeasurement.
Page 7
Student'sSheet
Printed:15/05/201913:08:11|P4110360
Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
Resultandevaluation
Resultsandevaluation
Results
Experiment1:Withtheplantusedinthispartoftheexperimentandinstillair,thepressuredecreasedbyapprox.2.8kPa
overameasurementtimeof1000s(Fig.3).
Fig.3:Measurementresult(Experiment1)–Planttranspirationinstillair
Experiment2:Duringthesamelengthoftimeinacoldflowofair,thepressuredecreasedbyapprox.3.8kPa(Fig.4),ina
hotflowofairbyapprox.6.3kPa(Fig.5).
Fig.4:Measurementresult(Experiment2b)–Planttranspirationinaflowofcoldair
Page 8
Student'sSheet
Printed:15/05/201913:08:11|P4110360
Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
Fig.5:Measurementresult(Experiment2b)–Planttranspirationinaflowofhotair
Experiment3:Notranspirationtookplaceinsteam(Fig.6).
Fig.6:Measurementresult(Experiment3)–Planttranspirationunderveryhighair
humidity
Evaluation
Plants"sweat"justaspeopledoandaretherebyphysiologicallyandmorphologicallysuitedtotheirspecificenvironment.They
transpireathightemperaturesandpasswatertotheenvironment.Transpirationservesforthetransportofwaterandnutrients.
Theunderpressurethatiscausedbytranspirationdrawswaterupfromtheroots,nutrientsaretransportedfromtherethrough
thestemtotheleaves.Innature,windplaysanimportantroleinthetranspirationofplants.Forexample,plantsthatgrowon
windyhillsidesaremorelignifiedandplantsthatgrowinthedesertsinktheirstomataintosmallleafhollowsthatare
additionallymattedandcoveredwithalayerofwax,sothatthetranspirationcausedbythehotdesertwindsiskeptaslowas
possible.Transpirationisgreatlylimitedwhenaplantisexposedtohighairhumidityasthesurroundingairisalreadysaturated
withwater.Plantsthatexistinareassubjectedtosuchhumidityhavestomatathatprotrudetoincreasetheirtranspiration.
Page 9
Student'sSheetPrinted:15/05/201913:08:11|P4110360
Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
Set-upandprocedure
Set-up
SetuptheequipmentasinFig.1.
Useoneofthetwosupportrodswhichisattachedtothesupportbasetoholdthetesttube.
AttachtheCobra4Wireless/USB-LinktotheCobra4Sensor-UnitPressuretotheholderontheothersupportrodinsuchawaythattheairintakenozzleoftheSensor-UnitPressureispositionedapprox.2cmhigherthanthehoseconnectorofthetesttube.
UseashortpieceofhosetoconnecttheairintakenozzleoftheSensor-UnitPressuretothehoseconnectorofthetesttube.
Fillthetesttubewithwaterandfastentherubberstopperwithoutanyformationofairbubblesinthetesttube.
SetupaconnectionoftheCobra4Wireless/USB-LinktothePCeitherwirelesslyorwiththeUSBcableandswitchiton.
Startthesoftware .TheCobra4measuringdevicewillbeautomaticallydetected.
Choosetheexperimentfromthestartscreenbyselecting`LoadExperiment`.Accordingly,choose“PHYWEexperiments”,searchfor“P4110360”,andselectdesiredfoldercontainingtheexperiment.Allnecessarypresettingwillbeloaded.
Procedure
Experiment1
Cutoffasmallleafyshootorasoil-plantjustabovethesoil.Peelfromthelowerpartoftheshootwithaknifeandcuttheendoffataslant(45°).
Quicklypushtheshootthroughthestopperandsealthestopperwellwithplasticine.
Withoutdelay,removethehosefromtheairintakenozzleoftheSensor-UnitPressure,fitthestopperwithplantonthetesttube(avoidingairbubbleformationinthetesttube)andfitthehosebackontheSensor-Unit.Caution!Donotletanywaterpenetrateintothepressuresensorwhiledoingthis!
Startmeasurement(idealrunningtime:atleast100s,butlongerisbetter–measurementwasmadefor1000sintheexamplegiven).
Taketheinitialandfinalpressuresfromthemeasuredvaluesandcalculatethedifference.
Experiment2a:(PreparationasforExperiment1)
Exposetheplanttoacoldflowofairfromthedryerduringmeasurement.
Experiment2b:
Setthedryertohotairandexposetheplanttothehotflowofairfromthedryerduringmeasurement.
Experiment3:
Bring½litreofwatertoboilingandcollectthesteamthatisgivenoffinaplasticbagforsomeseconds(Caution!Donotallowtheplasticbagtotouchthehotbeaker!).
Puttheplasticbagovertheplant,closeitwithanelasticbandandstartmeasurement.
Page 10
Student'sSheet
Printed:15/05/201913:08:11|P4110360
Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
Resultandevaluation
Resultsandevaluation
Results
Experiment1:Withtheplantusedinthispartoftheexperimentandinstillair,thepressuredecreasedbyapprox.28hPa
overameasurementtimeof1000s(Fig.3).
Fig.3:Measurementresult(Experiment1)–Planttranspiration
instillair
Experiment2:Duringthesamelengthoftimeinacoldflowofair,thepressuredecreasedbyapprox.38hPa(Fig.4),ina
hotflowofairbyapprox.63hPa(Fig.5).
Fig.4:Measurementresult(Experiment2b)–Plant
transpirationinaflowofcoldair
Fig.5:Measurementresult(Experiment2b)–Plant
transpirationinaflowofhotair
Page 11
Student'sSheet
Printed:15/05/201913:08:11|P4110360
Robert-Bosch-Breite10 Tel:+49551604-0 [email protected]
D-37079Göttingen Fax:+49551604-107 www.phywe.com
Experiment3:Notranspirationtookplaceinsteam(pressuredifferenceapprox.2hPa,Fig.6).
Fig.6:Measurementresult(Experiment3)–Planttranspiration
underveryhighairhumidity
Evaluation
Plants"sweat"justaspeopledoandaretherebyphysiologicallyandmorphologicallysuitedtotheirspecificenvironment.They
transpireathightemperaturesandpasswatertotheenvironment.Transpirationservesforthetransportofwaterandnutrients.
Theunderpressurethatiscausedbytranspirationdrawswaterupfromtheroots,nutrientsaretransportedfromtherethrough
thestemtotheleaves.Innature,windplaysanimportantroleinthetranspirationofplants.Forexample,plantsthatgrowon
windyhillsidesaremorelignifiedandplantsthatgrowinthedesertsinktheirstomataintosmallleafhollowsthatare
additionallymattedandcoveredwithalayerofwax,sothatthetranspirationcausedbythehotdesertwindsiskeptaslowas
possible.Transpirationisgreatlylimitedwhenaplantisexposedtohighairhumidityasthesurroundingairisalreadysaturated
withwater.Plantsthatexistinareassubjectedtosuchhumidityhavestomatathatprotrudetoincreasetheirtranspiration.
