设计改1.1我国土壤中钾钾肥资源状况

文献综 我壤中钾素及钾肥资源状 土壤的供钾潜 我国钾肥资源状 钾对植物抗旱性的影 对植物根系的影 对细胞结构的影 对可溶性渗透物质的影 对氮代谢的影 激素对植物生长的影 IAA对植物生长的影 GA对植物生长的影 ZR对植物生长的影 ABA对植物生长的影 抗氧化酶活性对植物生长的影 钾与激素以及抗氧化酶活性的关系研究现 植物的吸钾机 植物激素对钾素吸收的调控作 抗氧化酶活性对钾素吸收的调控作 材料与方 试验材 试验设 试验进程与测试项 试验进 测试项目及方 数据分 结果与分 干旱胁迫下不同浓度钾对玉米生长发育的影 干旱胁迫下钾对玉米激素含量的影 参考文献 附 致 文献综作用。同时，前人研究表明，IAA、GA、ZR、ABA等多种激素以及抗氧化酶活性均显IAA，GA，ZR，ABA等其他激素以及抗苗期采用15%PEG-6000模拟干旱胁迫，外源施用不同浓度的钾，测定不同处理玉米生我壤中钾素及钾肥资源状土壤的供钾潜133-1330pH我国钾肥资源状个非常重要的措施。我国80年始推广钾肥施用技术和进行平衡施肥研究，进入对植物根系的影0.2mm，这有利于水稻磷、钾的吸收，也增加了水稻根系的再生能力。对细胞结构的影对可溶性渗透物质的影钾能促进细胞内渗透调节物质的积累，使细胞膨压增加，在提高作物的抗旱性中提高作物的渗透调节能力起着重要的作用。干旱条件下，钾能明显促进钾在植物的吸收，增加植物体内钾离子的含量。研究表明，小麦叶片细胞中钾离子渗透的相对贡献高达45%～5%，是渗透势的主要成分。因为钾离子的离子半径小，水合作用大，形成在提增加烟叶的钾含量汪等研究表明在严重干旱胁迫条件下烟草植株的生长明显受6。还可能促进干旱条件下植物脯氨酸的积累。城的研究表明，高粱幼苗期水分亏缺，（1）（2（3）对氮代谢的影钾离子可以大大提高作物对硝酸根离子吸收 和还原，并迅速转化为蛋白质IAA对植物生长的影IAA在农业上的应用是非常广泛的，但它在植物中是量是非常小的，并且提取很困（NAA，2，4—D，也具有IAA的生理效应。这些化学物质，叫做IAA类似物，它可IAAIAA类似物溶液处理未的柱头，子房也能发育成果实，但是因为胚珠内卵细胞IAA能够促进子房壁发育成果实。因此，它被广泛用于防止落花落果，尤其是在温IAA为防止落花落果。GA对植物生长的影GA能促进生长，特别是促进无植物的整体生长。植株矮化主要是由于体GAGA，就可以由矮化恢复正常。莲座状植物，即使在非诱导条件下，GA处理可使其抽薹。而对根的生长一般是没有效果的。GA促进生长的这种作用，其实是促进细胞和细胞伸长的两方面，但认为促进伸长的作用与IAA的作用密切相关。此外，GA打破和芽的休眠，促进长日照植物GA的生理作用还有促进麦芽糖的转化，通过诱导α-淀粉酶形成；还可以促进营养生长（对根的生长无促进作用，可显著促进茎叶的生长，防止脱落和打破休眠等GAGA3，它可以显著地促进植物茎、叶的生长，激活中的多种水解酶，促进新酶合GA的很多生理效应与其调节植物组织内的蛋白质和核酸有关，它不仅可以激活种苷酶的合成。GA能够刺激茎伸长与核酸代谢有关，它首先作用在DNA，使得DNA活mRNAmRNA翻译成特定的蛋白质。GA铃薯块茎休眠；在啤酒酿造时，用GA3来促进麦芽糖用的大麦萌发；当晚稻ZR对植物生长的影IAA有在IAA存在的前提条件下才能体现出来。GA促进细胞是缩短细胞周期在G1（DNA合成期）和S（DNA合成）期的时间，从而加速细胞1957年和斯库格在进行烟草组织的培养时发现，ZR和IAA的相互作用控制着在离体叶片部分涂上ZR，则在叶片其它部分衰老变黄时，涂有ZR的部位仍然保持ZRZR不容易移动。此外，ZRZR能够延缓衰老是由于另一个原因，促进物质的积累。有很多数据表明，ZR可以促进核酸和蛋白质合成。例如，以，ZR可以在转录水平上对衰老的预防产生作用由于ZR有保绿及延缓衰老等作用，能在中萌发，用ZR可替代光打破休眠促进萌发。ZR也能解除IAA造成的顶GAZRZRABA对植物生长的影ABAABAABAABA处理马铃薯，延长休眠期。红松，桃，板栗，枫树和其他休眠的，的ABA。经过几个月的低温层积处理，可以降低中ABA的含量，使得发芽率显著提高。但ABA的含量，不一定是休眠的直接原因。红松种ABAABA含量显著降低，但发芽率很低。通过对华山松，云南松，白皮松，油松ABA含量的进一步分析，发现一些松树ABA含量也较高，但并未表现休眠。比如，非休眠的华山松的ABA含量高于红松ABA含量约为10倍。萝卜，莴苣的萌发，也会受到ABA抑制。加速植物脱从ABA的名称可以了解到，植物的加速脱落是ABA的一个重要的生理作用。ABAAddicottABA的一个发现者，ABAABA作为脱叶剂IAA，ZR，GAABA有一定的影响。Milborrow（1984）ABA能造成脱落，但比外源乙烯的影响低。奥斯本（1989）ABA脱落的影响得出结论，ABA在脱落方面可能没有直接的影响，ABA。调节胚的发这表明，发育早期，ABA控制贮藏蛋白质的积累水平。ABA是否也控制着淀粉和ABA能够诱导一些酶的重新合成从而提高植物抗寒性，抗盐性和抗涝性。因此，ABAABA含量增加，从而引起气孔关闭，这是由于脱落能够促使细胞的钾离子外渗细胞失水引起气孔关闭ABA溶液喷洒植物叶片，气孔关闭，减少蒸腾速率。因此，ABA可作为抗蒸腾剂。GA能使雌株形成雄花，这种影响可以被ABA逆转，但ABA不可使雄株形成。。上起到重要作用等选用15个抗旱性不同的玉米单交种为试验材料以Hoagland20%PEG8000处理幼苗，出现萎蔫症状时取样测定，结果表明，CAT活性和SOD与玉米品种的抗旱性呈正相关，抗旱性强的品种的CAT活性高于抗旱性弱的品种[9]等的研究结果表明，在水分胁迫下抗旱性CAT024h内CAT2448h内降低幅度较小:而抗旱CATCAT活性明显高于抗旱性弱的品种，说明水分胁迫下玉米叶片的CAT活性与品种的抗旱性SODPOD和CATSOD，POD和CAT活性均出现了下降的趋势。等以小麦为研究材料研究了干旱抑制RuBPSODPODMDA含量[10]PODPOD活性与品种的抗旱性之间无规律关系敏认为轻度中度聚乙二醇(PEG)胁迫模拟干旱胁迫时，SOD，。。20%PEG不如CAT和SOD敏感，与品种抗旱性关系不密切，SOD在减轻活性氧导致的膜损伤方PODCAT起更为重要的作用。植物的吸钾机1%5%，大约占植物灰分重量的一半。钾并非Epstein131~20μmol/L供给能量，所以是一个主动的过程。用。它们都强烈地依赖于膜电位，而且能够被钾离子通道抑制剂TEA所抑制，人们开1~10mmol/L起主要作用[15]。到目前为止，已经从个过程不直接与TP水解相耦连一般认为这是一个的过程根据蛋白质的列和结构特征它们被分为三个钾离子通道族RrK和16。。们在植物钾离子吸收转运中所发挥的作用还不清楚等认为钾元素的吸收是一个。植物激素对钾素吸收的调控作（1）意的是，不同的部位钾离子离子通道受ABA的影响是不同的，玉米细胞和根中的钾离子离子通道受ABA的调节就是相反的[19]ABA在细胞中可以增加钾离子的外流，减少钾离子的内流。叶肉细胞与细胞质膜上的钾离子通道受ABA的影响也Agazio等发现，为钾离子的竞争性抑制剂，会抑制钾离子的内流[20]ABA和多胺以外，IAA类、抗氧化酶活性对钾素吸收的调控作的产生速率、过氧化氢和MDA的含量显著增加，SOD、POD的活性均显著下降[21]；缺钾减少了对NAD(P)H氧化酶活性的抑制作用，降低了光合作用的电子传递，因而可以极大地促进ROS的产生缺钾处理使玉米幼苗的POD活性、叶绿素和蛋白质的含量都降低，但MDA的含量和乙醇酸氧化酶的活性升高。与水稻和玉米相似，缺钾处理也提高了大豆叶片MAD和过氧化氢的含量增加了叶片的电导度但却提高了抗氧化酶如SOD、POD和CAT的活性。这些结果表明，尽管缺钾处理时植物叶片的抗氧化酶活性的变化不尽相同，但ROS、MDA含量或者电导度的增加，意味着植物细胞的膜系统由于缺钟 材料与方供试的2种玉米品种为：958和浚单20。958是典型的抗性好，结实2014518日在西北农林科技大学北校标本园大棚进行。播浸湿（本实验选用的营养液为改良后的营养液。播种深度约5cm，每盆种两粒515%PEG-600036下共放入密封袋中将根剪下共四个装入一个密封袋中放入液氮内速冻便之后测定抗氧化酶活性。试验进201465日进行干旱处理，分别于、、、、、日取样测定植株株高与根长，分别于、、、、日测定地上部干物质重与根部重量。2014618，192014年8月29日，将密封袋中的干样取出，每个处理约取5g，在研钵中分三次共201491，2，3IAA，GA，ZR，ABA2014910MDA2014917SOD测试项目及方IAA，GA，ZR，ABA含量测定方法：酶联免疫试剂盒（购自中国作物化MDASODNBT数据分SPSSOrigin结果与分由表3-13-1IAA3.1可以看到，干旱胁迫下，IAA含量明显低于正常情况。但随着钾浓度的增加，干旱胁IAAIAA含量高于抗旱性弱的品：GA作为植物生长的必需激一调控植物生长发育的各个方面如萌发，3.2可以看到，干旱胁迫下，GA含量明显低于正常情况，且抗旱GA含量低于抗旱性弱的品种。：3.3可以看到，在干旱胁迫下，ZR含量明显低于正常情况。但同一品种在干旱胁迫时，高钾处理的玉米ZRZR含量没有明显差异。ABA是一种有效的生长抑制剂，能抑制整株植物或离体的生长。ABA制胚芽鞘，茎，根和下胚轴等其他伸长生长。从图3.4可以看到，随着钾浓度ABA含量呈下降趋势。同一品种在干旱胁迫下，ABA含量明显高于正常情况，且钾浓度与ABA含量呈正相关。不同品种间ABA含量也有较大差异，抗旱性强的品ABA含量低于抗旱性弱的品种。干旱条件下植物体内活性氧积累导致膜质过氧化而引起膜的，而活性氧的积累（MDA趋势，两个品种叶片MDA含量呈曲线变化（如图3.5。在干旱处理前四天，叶片MDA到破坏，植物受到氧化胁迫。但正常水分处理情况下，MDA含量不随钾浓度变化而变MDA活性与品种的抗旱性呈正相关，可以作为鉴定玉米抗旱性的指标。利于消除氧自由基，减轻干旱胁迫对细胞膜的，从而提高植物的抗旱能力。3.6SOD活性的调节，有利于消除活性氧自由基，减轻了干旱胁迫对分处理情况下，SOD,干旱胁迫下两个不同耐旱性玉米自交系苗期生长发育及生理生化特性的差异.沈阳崔华威,低温干旱胁迫对烟草发芽和幼苗生长的影响及提高其抗寒抗旱性的研究.浙江大学,干旱胁迫对小麦苗期生长的影响及其生理机制.2009,魏永胜,干旱胁迫和不同土壤钾水平下烟草植株钾的分布及其抗旱性研究.2001,西北农林Satoshi,Y.,etal.,Simultaneouscrystallizationofphosphateandpotassiumasmagnesiumpotassiumphosphateusingbubblecolumnreactorwithdraughttube.JournalofEnvironmentalChemicalEngineering,2013.1(4).,氮钾营养对菠菜生长、硝酸盐累积的影响及机理研究.2002,浙江大学唐浩,小麦和玉米生长过程中氮钾水互作效应研究.2008,中国农业,扩展蛋白与植物激素调节的干旱胁迫下小麦细胞生长的关系研究.2011,山东农业大学,Cd对玉米生理生化特性及土壤微生物和酶活性的影响2014,西南大学,外源过氧化氢对干旱胁迫下两种生态型黄瓜叶片抗氧化酶与DNA甲基化的影响2010,山东,干旱对玉米光合生理及相关酶表达的影响.2014,石河子大学D,K.C.andH.A.M,Effectsofmicrosomalenzymeinducersonthyroidfollicularcellandthyroidhormonemetabolism.ToxicologicPathology,2001.Hoseini,S.M.,A.Hedayati,andM.Ghelichpour,smametabolites,ionsandthyroidhormoneslevels,andhepaticenzymes׳activityinCaspianroach(Rutilusrutiluscaspicus)exposedtowaterbornemanganese.EcotoxicologyandEnvironmentalSafety,2014.107.Bhalla,A.S.andR.A.Siegel,Mechanisticstudiesofanautonomouslypulsinghydrogel/enzymesystemforrhythmichormonedelivery.JournalofControlledRelease,2014.L,L.J.,S.-K.C.A,andZ.C.J,RegulationoftypeIIiodothyronine5'-deiodinasebythyroidhormone.InhibitionofactinpolymerizationblocksenzymeinactivationincAMP-stimulatedglialcells.TheJournalofbiologicalchemistry,1990.265(2).FU,J.,etal.,ChangesinEnzymeActivitiesInvolvedinStarchSynthesisandHormoneConcentrationsinSuperiorandInferioreletsandTheirAssociationwithGrainFillingofSuperRice.RiceScience,2013.20(2).,外源激素对茶树菇液体培养胞外酶活性影响的研究.2008,西南大学N,M.J.andS.B.H,Growthhormoneregulationofhepaticdrug-metabolizingenzymesintheBiochemicalpharmacology,1989.,钾营养与激素调控对水培棉花生长发育与生理特性的影响.2008,周继华,外源激素GA_3与ABA对烟草株高及烟草叶片含钾量的影响.2009,金维环,转EdHP1（氢离子焦磷酸化酶）烟草促进磷、钾吸收的生理机制及调控机制的研究.2010,西北农林科技大学.,缺钾对水稻叶片光合特性、抗氧化酶的影响及其诱导早衰机制的研究2006,浙江大学ntgrowthregulationenhancedpotassiumuptakeanduseefficiencyinTheeffectsofntgrowthregulators(PGRs)andpotassium(K)fertilizeroncotton(Gossypiumhirsutum)yieldhavebeenwelledbuttheroleofPGRsonKuseefficiencyispoorlyunderstood.OurspecificobjectivewastodeterminewhetherfoliarapplicationofPGRscouldimproveKuseefficiencyinfield-growncotton.FieldexperimentswereconductedwithorwithoutKattwosites(BeijingandHebei,)varyinginavailablesoilKduring2010and2011,withcottoncvs.Guoxinmian3(GX3)andSCRC28astestmaterials.FoliarapplicationofthePGRs,mepiquatchloride(MC)andMiantaijin[MTJ,acombinationofMCwithdiethylaminoethylhexanoate(DA-6)]duringsquaringandfloweringperiodssignificantlyincreasedthelintyieldandKuptakeinmostsituationsatBeijinglocationandhadaconsistenttendencytoincreaselintyieldacrossKfertilizersandyearsatHebeilocation.Thepartialfactorproductivity(PFPK)andagronomicefficiencyofK(AEK)wereenhancedbytheapplicationofthePGRsinmostsituationsinBeijing,especiallyin2011andforthecultivarGX3.AlthoughdifferencesintheapparentrecoveryefficiencyofK(REK)betweenPGRsandcontrolwerenotsignificant,apositiveandconsistenteffectivenessofPGRsonREKwasobservedacrosssites,yearsandcultivars.Therefore,theapplicationofPGRswouldbeausefulpracticeforimprovingKnutritionandloweringthecostofKfertilizerinputincottonproduction..MaterialsandLocationsandFieldexperimentswereconductedduring2010and2011growingseasonatShangzhuangexperimentalstationofAgriculturalUniversitywithasandyloamsoilinBeijing(40◦08E,Elev.51m;hereafterreferredtoasBeijing)andHejiancitywithaclayloamsoilinHebeiprovince(38◦41N,116◦09E,Elev.11m;hereafterreferredtoasHebei).Soilorganicmatter,totalN,availableN,Olsen-P,exchangeableKandpHoftopsoil(20cm)weredeterminedfollowingproceduresofBao(2000),andpresentedinTableTheclimateofbothsitesiswarm-temperateandsubhumidcontinentalmonsoonwithcoldwintersandhotsummers.TherainfallisvariablewithgreaterdistributioninJulyandAugust.Cottonisusuallyntedinmid-AprilandharvestedattheendofOctober.Themonthlyaverageairtemperatureandrainfalldurationduringthegrowingseason(2010–2011)arepresentedinFig.1.Twohigh-yieldingcommercialcottoncultivars,Guoxinmian3[containingBtgeneandcowpeatrypsininhibitor(CpTI)gene,developedbyGuoxinSeed;hereafterreferredtoasGX3]andSCRC28(containingBtgene,developedbytheCottonResearchCenter,ShAcademyofAgriculturalSciences),wereusedatBeijingsite;andonlyGX3wasusedatHebeisite.Acid-delintedseedswithimidaclopridseedcoatingofGX3andSCRC28wereprovidedbyGuoxinCottonseed,,andLuyiCottonseed,.ThePGRs,MC(97.5%SPfromHebeiGuoxinNuonongBiotechnologyCo.,)andMTJ(250gMC+25gDA-6/lSLfromFujianHaoLunBiologicalEngineeringTechnologyCo.,)wereused.ExperimentInBeijing,a2(cultivars)×3(PGRs)×2(Krates)factorialexperimentusingarandomizedcompleteblockdesignwithfourreplicateswasconductedin2010and2011.Therewere48plots,eachmeasuring44.8m2(8×5.6m).Plotsconsistedoffourpairedrowspacing90+50cmatantdistanceof27.0cm(5.3ntsm−2),witharowlengthof8m.Thecottoncultivars,GX3andSCRC28wereseededon8May2010and30April2011.TheMCandMTJwerefoliarappliedthreetofourtimesduringsquaringandfloweringperiod,withtapwaterascontrol.DetailsoftimingandrateofapplicationofMCorMTJaregiveninTable2;theMCrateinMTJwasthesameasinMCaloneeachtime.ThetwoKfertilizertreatmentswereK0(control,noKfertilizerapplied)andK1(withKfertilizerapplied).Beforesowing,109kgNha−1,207kgP2O5ha−1,and145kgK2Oha−1(onlyforK1plots)wereplowedintothesoilin2010while98kgNha−1,172kgP2O5ha−1,and145kgK2Oha−1wereappliedin2011.Atfullflowering,165kgNha−1,andkgK2Oha−1(onlyforK1plots)weretopdressedin2010;and83kgNha−1,and86kgK2Oha−1inInHebei,a2(PGRs)×2(Krates)factorialexperimentusingarandomizedcompleteblockdesignwithfourreplicateswasconductedin2010and2011.Therewere16plotswitheachmeasuring30m2(6×5m).Plotsconsistedofeightrowsspaced90cmapartby6m.Thentingdistancewithinrowswas21.0cm(5.3ntsm−2).Thecottoncultivar,GX3wasseededon24April2010and21April2011.OnlyMTJwasfoliarappliedinHebei,withtapwaterascontrol.DetailsoftimingandrateofMTJapplicationaregiveninTheKfertilizertreatmentsconsistedofK0(control,noKfertilizerapplied)andK1(withKfertilizerapplied).Beforesowing,48kgNha−1,138kgP2O5ha−1,and45kgK2Oha−1(onlyorK1plots)wereplowedintothesoil.Atfullflowering,138kgNha−1and45kgK2Oha−1(onlyforK1plots)weretopdressed.Thetimingandratesoffertilizersapplicationweresamein2010and2011.ThesourcesofN,P,Kwereurea(46%N),diammoniumphosphate(46%P2O5,16%N),andpotassiumsulfate(48%K2O),respectively.FieldAtbothlocations,theplotswereirrigated15dbeforesowingeachyear.Soilswerethenplowedandharrowedwhentheirmellownesswasconsideredphysicallyacceptable.Hillseedingwithsticfilmmulchingwasappliedinthepresentstudy.Onevigorousntperstandwasretainedatthetwo-leafedstage.Vegetativebranchesandapexofmainstemwereremovedbyhandatpeaksquaringstageandoneweekafterpeakflowering.ChemicalcontrolofinsectandweedswereconductedaccordingtolocalagronomicDataDatawerecollectedforlintyield,yieldcomponents,biologicalyieldaswellastheuptakeanddistributionofN,PandK.YieldandyieldEachplotwasmanuallyharvestedthreetimes.Seedcotton(moisture≤11%)wasginnedona10-saw,hand-fedlaboratorygin,andlintyield(kg/ha)aswellaslintpercentage(lint/seedcotton,w/w)wasdeterminedafterginning.Thenumberofbollsperntandbollweight(moisture≤11%)weredeterminedfrom10ntsinthecentralfourrowsofeachplot.BiologicalyieldandnutrientuptakeandTenuniformntstaggedatsquaringstageineachplotweremanuallyuprootedatmaturity.ntdebriswasestimatedbycollectingallrecognizablentmaterialwithin1m2framescedbetweenrowsatweeklyintervals.Thentsweredividedintoroots,stems,leaves,bollss,debris,seeds,andlinttodryingat80◦Ctoaconstantweight.TheweightsofallpartswererecordedforcalculatingtheuptakeofK(2010and2011)andNandP2O5(2011).AllstalkpartsincludingdebrisweremilledwithaRT-34mill(RongTsongPrecisionTechnology)andscreenedthrougha0.5mmsieve.ForKdetermination,about0.1gfinepowdersamplesofroots,stems,leaves,anddebrisweresoakedin1.0MHClandshakenfor5h,andabout0.2gseedsorlintweredigestedfor1–4hin70%concentratedH2SO4and30%H2O2followingtheprocedureoutlinedinBao(2000).ExtractsweredilutedandyzedforKcontentusinganatomicadsorptionspectrophotometer(SpectAA-50/55,Varian,Australia).NitrogenandPweremeasuredbytheKjeldahlmethod(B-324,Buchi,Switzerland)andcolorimetricmethod(Cary100,Varian,Australia),respectively.yseswereperformedinPotassiumuseInthepresentstudy,theKuseefficiencywasexpressedinseveralways.Partialfactorproductivity[PFPK,thelintyield(kg)perunit(kg)ofK2Oapplied],agronomicefficiency[AEK,theincreasedlintyield(kg)overK0plotsperunit(kg)ofK2Oapplied],physiologicalefficiency[PEK,theincreasedlintyield(kg)perunit(kg)ofincreasedK2OuptakeoverK0plots],apparentrecoveryefficiency(REK,thepercentageofaddedK2Othatwasrecoveredinthentbiomassattheendofthegrowingseason)werecalculatedaccordingtothefollowingequations:whereLYiisthelintyield(kgha−1)ofK1treatment,LYckisthelintyield(kgha−1)ofK0control.UiistheKuptake(kgK2Oha−1)ofK1treatment,UckistheKuptake(kgK2Oha−1)ofK0control.FK2OistheamountofK2Oapplied(kgK2Oha−1)inK1treatment.StatisticalSASsoftware(V8,SASInstituteInc.,Cary,NC)wasusedforstatisticalysisofvariance.TreatmentsmeanswerecomparedusingDuncan’smultiplerangetestsat5%probabilitylevel.TheinitialcombineddatashowedinctionsbetweenyearsandcultivarsoryearsandKfertilizers.Thus,allthedatawerepresentedseparayforeachyearandcultivar.LintyieldandyieldLintyieldandyieldcomponentsvariedsignificantlyacrossyears(exceptbollnumbers),cultivars(exceptbollweight),Kfertilizers,andPGRs(exceptlintpercent)atBeijinglocation(Table4).Also,theyearbycultivar,yearbyKandyearbyPGRinctionseffectsonlintyieldweresignificant(Table4).TheapplicationofKfertilizersubstantiallyincreasedlintyieldandyieldcomponents(Table4).However,themagnitudeofKfertilizereffectin2011waslowerthanthatin2010becauseoftheexcessiveprecipitationinJulyandAugust2011inBeijing(Fig.1).TheeffectsofthePGRsonlintyieldvariedwithyearsandcultivars,andtheyweregreaterin2011thanin2010andforGX3thanSCRC28.Forexample,withoutKapplication,thePGRsincreasedthelintyieldofGX314–15%in2010and47–50%in2011;whenKfertilizerwasapplied,thePGRsincreasedlintyield6.7–22%in2010and45–48%in2011.ForSCRC28,thePGRshadnoeffectsonlintyieldin2010,butincreasedit16–31%and29–30%in2011at0and201kgK2Oha−1.ThegreatereffectivenessofPGRsonlintyieldin2011resultedfromtheirgreatereffectsonnumberofbollsandlintpercent(exceptforMTJinSCRC28)in2011(Table4).AtHebeilocation,thelintyieldvariedsignificantlyacrossyearsandKfertilizersbutnotforPGR(Table5).Moreover,theyearandKfertilizereffectsweresignificantforbollnumberandbollweight.AlthoughtherewasnosignificantinctioneffectbetweenandKfertilizeronlintyield,Kapplicationincreasedlintyieldmoreconsiderablyin2011(24%)thanin2010(15%).Furthermore,thePGRonlyhadatendencytoincreaselintyieldinHebei(Table5).Kuptake,distributionandharvestAtBeijinglocationwithalowKsoil,theKuptake,anddistributioninstalks,seedandlintaswellasKharvestindex(KHI,theratiooflintKtototalKuptake)variedsignificantlyacrossyears,Kfertilizers,andPGRs(exceptKHI)(Table6).TheinctioneffectsofyearbyKfertilizeronKuptakeanddistributionwerealsosignificant(Table6).InBeijing,theKuptakein2011wasmuchlowerthanthatin2010duetoleachinglossesbyheavyprecipitationinJulyandAugust2011.TheapplicationofKfertilizerresultedinan84%increaseinKuptakein2010,anda52%increasein2011acrosscultivars.InplotswithoutKinput(K0),theapplicationofMCandMTJdidnotaffecttheKuptakein2010,butcausedasignificantincreasein2011.However,thePGRssignificantlyenhancedtheKuptakewhenKfertilizerwasappliedwhetherin2010orin2011,buttheireffectsonKuptakewerestrongerin2011(27–33%)thanin2010(6–10%;Table6)underK1treatment.PotassiumapplicationincreasedtheKHIatBeijinglocation,especiallyin2010(Table6).ThePGRsdidnotaffectKHI,buttendedtoincreasetheKHIofGX3in2011(albeitinsignificant;Table6).AtHebeilocationwithahighKsoil,theKuptakeanddistributioninstalks,seedandlintaswellastheKHIvariedsignificantlyacrossKfertilizersandPGRs(Table7).TheinctionseffectsofyearbyKfertilizerontheseparameterswerealsosignificant(exceptstalkK).TheyeareffectsweresignificantforstalkK,seedKandKHI,butnotforlintKandKuptake.TheKuptakeincreasedby16–25%whenKfertilizerwasappliedatHebeilocation(Table7).FoliarsprayofMTJcausedasignificantandconsistentincrease(8–10%)inKuptakeacrossKfertilizersandyears(Table7).TheapplicationofKfertilizerandMTJdidnotaffecttheKHIin2010.KuseInthisstudy,KuseefficiencywasdescribedbyPFPK,AEK,PEKandREK.AlltheseindicessignificantlyvariedacrossyearsatBeijingsitewithalowKsoil(Table8),suggestingaweathereffectonKuseefficiencyincotton.ThePGRssignificantlyaffectedPFPKandAEK,asweretheinctioneffectsofyearbycultivarandyearbyPGRsonPFPK(Table8).In2011,theapplicationofMCandMTJsignificantlyincreasedPFPKofthetwocultivars,andhadatendencytoimproveAEK,PEKandREK.In2010,noconsistenteffectofPGRswereobservedintermsofPFPK,AEKandPEK,butpositiveeffectonREKoccurredin2010(Table8).AtHebeilocationwithahighKsoil,asignificantyeareffectwasobservedforPFPK,AEKandREK(Table9).Inaddition,theMTJapplicationincreasedREKconsistentlyacrossthetwoyears,whichwassimilartotheresultsinBeijing(Table8).NutrientbalanceincottonNitrogenandPuptakewasaffectedbytheapplicationofKfertilizersandPGRs.InBeijing2011,theaccumulationofNandP2O5increasedby30%and24%inGX3ntsand25%and28%inSCRC28ntswhen231kgK2Oha−1wasapplied,beinglowerthanthe51–52%increaseinK2Oaccumulationinthetwocultivars(Table10).Also,theresponseofK2OaccumulationtothePGRswasstrongerthanthatofNandP2O5(exceptP2O5ofGX3inK1plots).WithoutKapplication,themeanvalueofNandP2O5accumulationacrossPGRsincreasedby13%and12%inGX3and16%and17%inSCRC28,ascomparedwithcontrolAthighrate(231kgK2Oha−1)ofKapplication,themeanvalueofNandP2O5accumulationacrossPGRsincreasedby21%and29%inGX3and15%and13%inSCRC28;whereasK2Oaccumulationinthetwocultivarsincreasedby30%.InHebei2011,similarresultswereobtained(Table11).Forexample,Kapplication(90kgK2Oha−1)enhancedNaccumulationby14%andP2O5accumulationby16%whereasK2Oaccumulationincreasedby25%.MTJdidnotaffecttheNandP2O5accumulationbutincreasedK2Oaccumulationby7–10%.Withregardtothenutrientsrequiredfortheproductionof100kglint,thentsusedapproximayequalK2O(about10–12kg)acrossallexperimentalfactorsincludingsite,year,cultivar,KfertilizerandPGR,nomatterwhattheyaffectlintyield;whereastheNandP2O5requirementsshowedevidentdeclineasyieldincreased(Table10).Therefore,theratioofK2Ointhelintincreasedwithincreasesinlintyield,duetotheapplicationofeitherKorPGRs.TheKapplicationconsistentlyincreasedtheratioofK2OacrosscultivarsandPGRs,andthePGRsalsoconsistentlyincreasedtheratioofK2OacrosscultivarsandratesofKfertilizer(Tables10and11).TheresultsofthisfieldstudyhaveaddednewinformationonKuseefficiencyincottonandtheeffectivenessofPGRsontheuseefficiency.KuseefficiencyincottongreatlyvariedwithsitesandInthepresentstudy,thereweregreatdifferencesinPFPKandAEKbetweensites(Beijingvs.Hebei),andinREKbetweenyears(2010vs.2011)atBeijinglocation,indicatingthattheresponsesofcottontoKfertilizerarecloselyconnectedwithlocalclimate(ToshevaandAlexandrova,2004).TheAEKrepresentstheproductofuptakeefficiencyfromappliedK(NovoaandLoomis,1981).Partialfactorproductivity(PFP)fromappliednutrientsprovidesanintegrativeindexofthetotaleconomicoutputrelativetoutilizationofallnutrientresourcesinthesystem,includingindigenoussoilnutrientsandappliedinputs(Cassmanetal.,1998).Bydefinition,PFP=(Y0/Nr)+AE.Y0/NrisamathematicaltermderivedfromseparatingthecontributionofyieldsupportedbyindigenousnutrientsresourcesfromtheyieldresponsetoappliednutrientsintheestimationofPFP(Cassmanetal.,1998).Inthepresentstudy,allthePFPKvaluesacrossyears,cultivarandPGRsinBeijingwerelessthan6kglintkg−1K2O(Table8),whereasallthevaluesacrossyearsandPGRsinHebeiweremorethan20kglintkg−1K2O(Table9).ConsideringtherelativelylittledifferencesinmeanAEKbetweensites(1.94kglintkg−1K2OinBeijingvs.3.99kglintkg−1K2OinHebei),itisclearthatthemuchlowerPFPKinBeijingwasmainlyduetothemuchlowercontributiontolintyieldbyindigenousnutrients.Indeed,thecontentsoforganicmatter,totalN,availableNandexchangeableKinBeijingsoilwerelowerthanthoseinHebeisoil.Moreover,thesoilfertilityinBeijingwaslowintermsofavailableNandexchangeableKbasedonthecriteriadescribedinLuetal.(2002).Itiswellknownthatnutrientsnotusedbythecropareatriskoflosstotheenvironment,butthesusceptibilityoflossvarieswiththenutrient,soilandclimaticconditions,andlandscape(Roberts,2008).Inthisstudy,theREKinBeijing2011wasonly0.11–0.16kgK2Okg−1,muchlowerthanin2010(0.31–0.36kgK2Okg−1)andthatforwheatandcorn(0.32–0.36kgK2Okg−1)intheNorth in(Zhangetal.,2008).ThelowREKinBeijing2011canbeattributedtoweatherconditions.TheprecipitationinJuly2011was195.4mmmorethanthatinthesameperiodin2010atBeijingsite(Fig.1).TheheavyraincanleadtoahugeleachinglossofavailableKfromtheKfertilizer.ThisresultissupportedbythatofPieriandOliver(1986)whoreportedthattheriskofleachinglossesofKunderhumidconditionsisveryhigh,whengenerousratesofKfertilizersareappliedonlydrainedsoils,suchasthesandyloamsoilatBeijingPGRsincreasedKuptakeandKuseefficiencyofcottontosomeAtBeijinglocation,bothMCandMTJsignificantlyincreasedthePFPKofeitherGX3orSCRC28in2011,andtendedtoincreasetheAEKofthetwocultivarsinthesameyear.Inaddition,thePGRsshowedaconsistenttendencytoenhancetherecoveryofKfertilizer(REK)acrossyears,sitesandcultivars,althoughthedifferenceswereinsignificantinmostsituations(Tables8and9).BecausethePGRsdidnotincreasethePEKincotton,withwhichthentutilizestheKacquiredfromappliedinputstoproducemorelint,wesuggestthattheincreasedPFPKandAEKfollowingPGRapplicationaremainlyassociatedwithgreaterKuptakefromindigenoussoilnutrientsand/orappliedinputs.TheincreasedREKfollowingPGRapplicationconfirmedthatPGRsenhancedtheKuptakeofcottonnts.PreviousworkshavedemonstratedthatcottonrootstreatedwithMCorMTJnotonlyhadlongerrootsandlargerrootsurfacearea(Tianetal.,2006a;Yang,2012),butalsoshowedhigherrootvigoranduptakeability(Jinetal.,1984;Heetal.,1988;ZhaoandOosterhuis,1997;Howardetal.,2001;Tianetal.,2006b).OurrecentunpublishedworkshowedthatsoakingseedswithMCsolutionincreasedthenetK+influxintherootmeristematiczoneofcottonseedlingsusingnon-invasivemicro-testtechnique(NMT).Moreover,Khanetal.(2005)suggestedthattheincreaseinNfertilizerrecoveryefficiencyduetoPGRapplicationwasassociatedwiththeenhancementofgrowth,leafcarbondioxideexchangerateandNuptakeandaccumulation.Also,PGRs(paclobutrazolandtrinexapac-ethyl)couldincreasethesoilorganicC,therebyincreasingthesoil’sCECoritsabilitytoholdontoandsupplyessentialnutrientssuchasCa,MgandK,and positionofsoilmineralsovertime,makingthenutrientsinthemineralsavailableforntuptake(López-Bellidoetal.,2010).Moreover,wenoticedthatMTJcaused“luxuryconsumption”intermsofKinHebei;i.e.MTJdidnotincreaselintyield,butimprovedKuptake.Ingeneral,K“luxuryconsumption”happedunderahighsoilavailableK,andisalsoinfluencedbysoilmoisture,levelofothercationelementsinsoil,andgrowthstatusofnts(Hommelsetal.,1989).Inthepresentstudy,thesoilavailableKinHebeiisashighas170mg/kgaround(Table1),whichistheprerequisitefor“luxuryconsumption”ofMTJtreatment.Inaddition,thepromotedrootgrowthandincreasednutrientsuptakefromsoilbyMTJapplication(Tianetal.,2006b)maycontributetotheK“luxuryconsumption”ofcottonnts.ThepositiveeffectofPGRsonKuptakeandKuseefficiencyofcottondidnotvarywithlintyieldlevelsThereweregreatdifferencesinlintyieldbetweenBeijingsiteandHebeisiteinthepresentstudy.TheaveragelintyieldinBeijingacrossyears,cultivars,KfertilizersandPGRswas738kgha−1,beingonlyequivalentto56%ofthatinHebei.ThereasonsforloweryieldinBeijingarethatthesoilfertilityispoor(seeaboveinSection4.1)andthecumulativeheatunit(15.5◦Cbase)islessthanthatinHebei(1185vs.1284degree-daysin2010;1150vs.1260degree-daysin2011).Doesalowlintyieldaffecttherel