Lettuce is one of several hydroponic crops now growncommercially.The whiteboards support the plants,whicharenot anchored in soil.A chemicallydefined liguidsolution of nutrient minerals trickles overtheirroots,whichalso have access to atmospheric oxygen.(HankMorgan/photoResearchers,lnc.)Figure 2-0
Figure 2-0
TABLE5.1Adequate tissue levels of elements that may be required by plantsConcentrationRelativenumberofChemicalin drymatteratomswithrespectElementsymbol(%orppm)ato molybdenumObtainedfrom waterorcarbondioxideHHydrogen660.000.000CCarbon4540.000.000OOxygen4530,000,000Obtained from thesoilMacronutrientsNNitrogen1.51,000,000KPotassium1.0250,000CalciumCa0.5125,000MgMagnesium0.280,000PPhosphorus0.260,000sSulfur0.130,000SiSilicon0.130,000MicronutrientsCIChlorine1003,000lronFe1002,000BBoron202,000ManganeseMn501,000SodiumNa10400ZincZn20300Coppercu6100NickelNiTable 2-10.12MolybdenumMo0.11Source:Epstein1972,1999.a The values for the nonmineral elements (H,C,O) and themacronutrients arepercentages.Thevaluesformicronutrientsareexpressedinpartspermillion
Table 2-1
TABLE5.3Table 2-2CompositionofamodifiedHoaglandnutrientsolutionforgrowingplantsConcentrationConcentrationVolumeofstockFinalMolecularofstockofstocksolution per literconcentrationCompoundweightsolutionsolutionof final solutionElementofelementgmol-19L-1mMmLHMppmMacronutrientsKNO,101.101,000101.106.0N16,000224Ca(NO,)2-4H,0236.161,000236.164.0K6,000235NH.H,PO115.081,000115.082.0Ca4,000160MgSO.7H,0246.481,000246.49P1.02,00062S1,00032Mg241,000MicronutrientsKCI74.55251.864CI501.77H,BO361.8312.50.773B250.27MnSO,H,O1.0169.010.169Mn2.00.112.0ZnSO7H,O287.541.00.288Zn2.00.13CuSO,-5H,O249.680.250.062Cu0.50.03H,MoO,(85%MoO,)161.970.250.040Mo0.50.05NaFeDTPA(10%.Fe)468.206430.00.3-1.0Fe16.1-53.71.00-3.00OptionalaNiSO,6H,O262.860.250.0662.0Ni0.50.03Na,SiO..9H,284.201,000284.201.0Si1,00028Source:AfterEpstein1972.Note:Themacronutrientsareadded separatelyfromstock solutions topreventprecipitationduring preparationof thenutrient solution.Acom-binedstocksolutionismadeupcontainingall micronutrientsexceptiron.Ironisaddedassodiumferricdiethylenetriaminepentaacetate(NaFeDTPA,tradenameCiba-GeigySequestrene33oFe;seeFigure5.2);someplants,suchasmaize,requirethehigherlevelofironshowninthetable.Nickelisusuallypresentasacontaminantoftheotherchemicals,soitmaynotneedtobeaddedexplicitly.Silicon,ifincluded,shouldbeaddedfirstandthepHadjustedwithHCltopreventprecipitationoftheothernutrients
Table 2-2
TABLE5.2Table 2-3Classificationofplantmineral nutrientsaccordingtobiochemical functionFunctionsMineralnutrientGroup1NutrientsthatarepartofcarboncompoundsNConstituentofaminoacids,amides,proteins,nucleicacids,nucleotides,coenzymes,hexoamines,etc.SComponentofcysteine,cystine,methionine,andproteins.Constituentoflipoicacid,coenzymeA,thiaminepyrophosphate,glutathione,biotin,adenosine-5-phosphosulfate,and3-phosphoadenosine.Group2Nutrients that are important in energy storage or structural integrityPComponentofsugarphosphates,nucleicacids,nucleotides,coenzymes,phospholipids,phyticacid,etc.HasakeyroleinreactionsthatinvolveATpSiDeposited as amorphous silicain cell walls.Contributesto cell wall mechanical properties,includingrigidityand elasticity.BComplexeswithmannitol,mannan,polymannuronicacid,andotherconstituentsofcell walls.Involvedincellelongationandnucleicacidmetabolism.Group3Nutrientsthatremain inionicformKRequiredasa cofactorformorethan 4o enzymes.Principal cation in establishing cell turgorand maintainingcellelectroneutrality.CaConstituentofthemiddlelamellaof cell walls.Requiredasacofactorbysomeenzymesinvolvedin thehydrolysisofATPandphospholipids.Actsasasecondmessengerinmetabolicregulation.MgRequiredbymanyenzymes involvedinphosphatetransfer.Constituentofthechlorophyll moleculeCIRequiredforthephotosyntheticreactions involved in O,evolution.MnRequiredforactivityofsomedehydrogenases,decarboxylases,kinases,oxidases,andperoxidases.Involvedwithothercation-activatedenzymesandphotosyntheticO,evolution.NaInvolvedwiththeregenerationofphosphoenolpyruvate inCand CAMplants.Substitutesforpotassiuminsomefunctions,Group4NutrientsthatareinvolvedinredoxreactionsFeConstituentofcytochromesandnonhemeironproteinsinvolvedinphotosynthesis,N,fixation,andrespirationZnConstituent.ofalcoholdehydrogenase,glutamicdehydrogenase,carbonicanhydrase,etc,CuComponentofascorbicacidoxidase,tyrosinase,monoamineoxidase,uricase,cytochromeoxidase,phenolase,laccase,andplastocyanin.NiConstituentofurease.InN,-fixingbacteria,constituentofhydrogenasesMoConstituentofnitrogenase,nitratereductase,andxanthinedehydrogenase
Table 2-3
Fluid lipiddomainwithGelled lipid domainaggregatedmembraneproteinsdevoid ofproteinGlycoprotein oligosaccharidesidechainsCentral planeoflipid bilayerOutsidecellLipidbilayerInsidecell(cytoplasm)Lipid-anchoredFigure 1.9PeripheralproteinAmodern version of themembraneIntegralfluid-mosaicmembraneproteinmembranemodel, depicting inte-Peripheralproteinsgral,peripheral, andmembranelipid-anchored mem-proteinbraneproteins.NotFigure 2-1-0drawntoscale
Figure 2-1-0
oPhosphatidylinositol-anchored proteinFigure 2-1-1EthanolamineGalactoseGlucosamineInositolPMannoseNHHOOutside cellOHOCeramideFattyacid-anchored proteinsPrenyl lipid-anchored proteinLipidbilayerMyristicPalmiticMFarnesyGeranylgeranyacidacidC14CeCAmideCytosolbondCHHNCH.HCHHOCH图&Figure 1.10Fattyacid-anchored,prenyl lipid-anchored,andglycosylphosphatidylinositol (GPI)anchoredproteins
Figure 2-1-1
OUTSIDEOFCELLGtycosyipnosphatidytinositol(Gpi)anchoredproteinEthanolaminePTGalactoseGlucasamineMannoseInositolPNHLipid bilayerHOOHWCeramideMyristicacid (Cra)Palmiticacid(Cre)Farnesyi(Cis)Geranylgeranyl(Czo)OaSAmidebondHNCH2CH,CH:HDGIC由Fattyacid-anchoredproteinsPrenyi lipid-anchoredproteinsCYTOPLASMFIGURE1.6Differenttypesofanchoredmembraneproteinsthatareattachedtothemembraneviafattyacids,prenylgroups,orphosphatidylinositol.(FromBuchananFigure 2-1-2etal. 2000.)
Figure 2-1-2
(A)(C)H.CCholineHCphosphateHydrophillregionColl wallGlycerolH.Plasmamembrane-HHHHHHHHHHCarbahydratesHHHHH.HOutsideofcellHHHHHHHHydrophobic1HAregionHHHydrophilicHHHregionHPhospholipidHHbilayerHtHHydrophobicHHHregionHhHHydrophilicregionPhosphatidylcholineCytoplasmtntegralPeripheralCholineproteinprotein(B)aGalactosepiasmamembranesOHAdjoiningprimarywallsFmVFIGURETS(A)Theplasrnamembranc,endoplasmieneticulum,and otherenclomembranes ofplantcellsconsistofphosphatidylcholineGalactosylglycerideproteins.embeddedinaphospholipidbilaver(B)rhistransmissionelectronmicrographshowsplasmamembranesincells fromthe uneristematicregion of a roottip ofcress(EpfiuntsatiouTheovorallthicknossoftheplaumamembrane,viewed astwo densg linesand an interveningspace,isFigure 2-1Bnm,(c)Chenicaistructures andspace-fillingmodelsoftypicalphospholipids:phosphatidyicholineandgalactosylglyceride-(BfromGunningandSteer1goo)
Figure 2-1
Figure 2-2 lon channel transport solutes processesOutsideofcellHigh2-CICaKKCICICaCaKKelectrochemicalpotential2+OW2C1aInsideof cellSimple diffusion(passivetransport)
Figure 2-2 Ion channel transport solutes processes
High soluteconcentrationElectrochemicalpotentiaPlasma membranelowsoluteconcentrationFig. 2-3 Uniport carrier transport solutes processes
Fig. 2-3 Uniport carrier transport solutes processes