設(shè)計改1.1我國土壤中鉀鉀肥資源狀況

文獻(xiàn)綜 我壤中鉀素及鉀肥資源狀 土壤的供鉀潛 我國鉀肥資源狀 鉀對植物抗旱性的影 對植物根系的影 對細(xì)胞結(jié)構(gòu)的影 對可溶性滲透物質(zhì)的影 對氮代謝的影 激素對植物生長的影 IAA對植物生長的影 GA對植物生長的影 ZR對植物生長的影 ABA對植物生長的影 抗氧化酶活性對植物生長的影 鉀與激素以及抗氧化酶活性的關(guān)系研究現(xiàn) 植物的吸鉀機(jī) 植物激素對鉀素吸收的調(diào)控作 抗氧化酶活性對鉀素吸收的調(diào)控作 材料與方 試驗材 試驗設(shè) 試驗進(jìn)程與測試項 試驗進(jìn) 測試項目及方 數(shù)據(jù)分 結(jié)果與分 干旱脅迫下不同濃度鉀對玉米生長發(fā)育的影 干旱脅迫下鉀對玉米激素含量的影 參考文獻(xiàn) 附 致 文獻(xiàn)綜作用。同時，前人研究表明，IAA、GA、ZR、ABA等多種激素以及抗氧化酶活性均顯IAA，GA，ZR，ABA等其他激素以及抗苗期采用15%PEG-6000模擬干旱脅迫，外源施用不同濃度的鉀，測定不同處理玉米生我壤中鉀素及鉀肥資源狀土壤的供鉀潛133-1330pH我國鉀肥資源狀個非常重要的措施。我國80年始推廣鉀肥施用技術(shù)和進(jìn)行平衡施肥研究，進(jìn)入對植物根系的影0.2mm，這有利于水稻磷、鉀的吸收，也增加了水稻根系的再生能力。對細(xì)胞結(jié)構(gòu)的影對可溶性滲透物質(zhì)的影鉀能促進(jìn)細(xì)胞內(nèi)滲透調(diào)節(jié)物質(zhì)的積累，使細(xì)胞膨壓增加，在提高作物的抗旱性中提高作物的滲透調(diào)節(jié)能力起著重要的作用。干旱條件下，鉀能明顯促進(jìn)鉀在植物的吸收，增加植物體內(nèi)鉀離子的含量。研究表明，小麥葉片細(xì)胞中鉀離子滲透的相對貢獻(xiàn)高達(dá)45%～5%，是滲透勢的主要成分。因為鉀離子的離子半徑小，水合作用大，形成在提增加煙葉的鉀含量汪等研究表明在嚴(yán)重干旱脅迫條件下煙草植株的生長明顯受6。還可能促進(jìn)干旱條件下植物脯氨酸的積累。城的研究表明，高粱幼苗期水分虧缺，（1）（2（3）對氮代謝的影鉀離子可以大大提高作物對硝酸根離子吸收 和還原，并迅速轉(zhuǎn)化為蛋白質(zhì)IAA對植物生長的影IAA在農(nóng)業(yè)上的應(yīng)用是非常廣泛的，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的生理效應(yīng)。這些化學(xué)物質(zhì)，叫做IAA類似物，它可IAAIAA類似物溶液處理未的柱頭，子房也能發(fā)育成果實，但是因為胚珠內(nèi)卵細(xì)胞IAA能夠促進(jìn)子房壁發(fā)育成果實。因此，它被廣泛用于防止落花落果，尤其是在溫IAA為防止落花落果。GA對植物生長的影GA能促進(jìn)生長，特別是促進(jìn)無植物的整體生長。植株矮化主要是由于體GAGA，就可以由矮化恢復(fù)正常。蓮座狀植物，即使在非誘導(dǎo)條件下，GA處理可使其抽薹。而對根的生長一般是沒有效果的。GA促進(jìn)生長的這種作用，其實是促進(jìn)細(xì)胞和細(xì)胞伸長的兩方面，但認(rèn)為促進(jìn)伸長的作用與IAA的作用密切相關(guān)。此外，GA打破和芽的休眠，促進(jìn)長日照植物GA的生理作用還有促進(jìn)麥芽糖的轉(zhuǎn)化，通過誘導(dǎo)α-淀粉酶形成；還可以促進(jìn)營養(yǎng)生長（對根的生長無促進(jìn)作用，可顯著促進(jìn)莖葉的生長，防止脫落和打破休眠等GAGA3，它可以顯著地促進(jìn)植物莖、葉的生長，激活中的多種水解酶，促進(jìn)新酶合GA的很多生理效應(yīng)與其調(diào)節(jié)植物組織內(nèi)的蛋白質(zhì)和核酸有關(guān)，它不僅可以激活種苷酶的合成。GA能夠刺激莖伸長與核酸代謝有關(guān)，它首先作用在DNA，使得DNA活mRNAmRNA翻譯成特定的蛋白質(zhì)。GA鈴薯塊莖休眠；在啤酒釀造時，用GA3來促進(jìn)麥芽糖用的大麥萌發(fā)；當(dāng)晚稻ZR對植物生長的影IAA有在IAA存在的前提條件下才能體現(xiàn)出來。GA促進(jìn)細(xì)胞是縮短細(xì)胞周期在G1（DNA合成期）和S（DNA合成）期的時間，從而加速細(xì)胞1957年和斯庫格在進(jìn)行煙草組織的培養(yǎng)時發(fā)現(xiàn)，ZR和IAA的相互作用控制著在離體葉片部分涂上ZR，則在葉片其它部分衰老變黃時，涂有ZR的部位仍然保持ZRZR不容易移動。此外，ZRZR能夠延緩衰老是由于另一個原因，促進(jìn)物質(zhì)的積累。有很多數(shù)據(jù)表明，ZR可以促進(jìn)核酸和蛋白質(zhì)合成。例如，以，ZR可以在轉(zhuǎn)錄水平上對衰老的預(yù)防產(chǎn)生作用由于ZR有保綠及延緩衰老等作用，能在中萌發(fā)，用ZR可替代光打破休眠促進(jìn)萌發(fā)。ZR也能解除IAA造成的頂GAZRZRABA對植物生長的影ABAABAABAABA處理馬鈴薯，延長休眠期。紅松，桃，板栗，楓樹和其他休眠的，的ABA。經(jīng)過幾個月的低溫層積處理，可以降低中ABA的含量，使得發(fā)芽率顯著提高。但ABA的含量，不一定是休眠的直接原因。紅松種ABAABA含量顯著降低，但發(fā)芽率很低。通過對華山松，云南松，白皮松，油松ABA含量的進(jìn)一步分析，發(fā)現(xiàn)一些松樹ABA含量也較高，但并未表現(xiàn)休眠。比如，非休眠的華山松的ABA含量高于紅松ABA含量約為10倍。蘿卜，萵苣的萌發(fā)，也會受到ABA抑制。加速植物脫從ABA的名稱可以了解到，植物的加速脫落是ABA的一個重要的生理作用。ABAAddicottABA的一個發(fā)現(xiàn)者，ABAABA作為脫葉劑IAA，ZR，GAABA有一定的影響。Milborrow（1984）ABA能造成脫落，但比外源乙烯的影響低。奧斯本（1989）ABA脫落的影響得出結(jié)論，ABA在脫落方面可能沒有直接的影響，ABA。調(diào)節(jié)胚的發(fā)這表明，發(fā)育早期，ABA控制貯藏蛋白質(zhì)的積累水平。ABA是否也控制著淀粉和ABA能夠誘導(dǎo)一些酶的重新合成從而提高植物抗寒性，抗鹽性和抗?jié)承?。因此，ABAABA含量增加，從而引起氣孔關(guān)閉，這是由于脫落能夠促使細(xì)胞的鉀離子外滲細(xì)胞失水引起氣孔關(guān)閉ABA溶液噴灑植物葉片，氣孔關(guān)閉，減少蒸騰速率。因此，ABA可作為抗蒸騰劑。GA能使雌株形成雄花，這種影響可以被ABA逆轉(zhuǎn)，但ABA不可使雄株形成。。上起到重要作用等選用15個抗旱性不同的玉米單交種為試驗材料以Hoagland20%PEG8000處理幼苗，出現(xiàn)萎蔫癥狀時取樣測定，結(jié)果表明，CAT活性和SOD與玉米品種的抗旱性呈正相關(guān)，抗旱性強(qiáng)的品種的CAT活性高于抗旱性弱的品種[9]等的研究結(jié)果表明，在水分脅迫下抗旱性CAT024h內(nèi)CAT2448h內(nèi)降低幅度較小:而抗旱CATCAT活性明顯高于抗旱性弱的品種，說明水分脅迫下玉米葉片的CAT活性與品種的抗旱性SODPOD和CATSOD，POD和CAT活性均出現(xiàn)了下降的趨勢。等以小麥為研究材料研究了干旱抑制RuBPSODPODMDA含量[10]PODPOD活性與品種的抗旱性之間無規(guī)律關(guān)系敏認(rèn)為輕度中度聚乙二醇(PEG)脅迫模擬干旱脅迫時，SOD，。。20%PEG不如CAT和SOD敏感，與品種抗旱性關(guān)系不密切，SOD在減輕活性氧導(dǎo)致的膜損傷方PODCAT起更為重要的作用。植物的吸鉀機(jī)1%5%，大約占植物灰分重量的一半。鉀并非Epstein131~20μmol/L供給能量，所以是一個主動的過程。用。它們都強(qiáng)烈地依賴于膜電位，而且能夠被鉀離子通道抑制劑TEA所抑制，人們開1~10mmol/L起主要作用[15]。到目前為止，已經(jīng)從個過程不直接與TP水解相耦連一般認(rèn)為這是一個的過程根據(jù)蛋白質(zhì)的列和結(jié)構(gòu)特征它們被分為三個鉀離子通道族RrK和16。。們在植物鉀離子吸收轉(zhuǎn)運(yùn)中所發(fā)揮的作用還不清楚等認(rèn)為鉀元素的吸收是一個。植物激素對鉀素吸收的調(diào)控作（1）意的是，不同的部位鉀離子離子通道受ABA的影響是不同的，玉米細(xì)胞和根中的鉀離子離子通道受ABA的調(diào)節(jié)就是相反的[19]ABA在細(xì)胞中可以增加鉀離子的外流，減少鉀離子的內(nèi)流。葉肉細(xì)胞與細(xì)胞質(zhì)膜上的鉀離子通道受ABA的影響也Agazio等發(fā)現(xiàn)，為鉀離子的競爭性抑制劑，會抑制鉀離子的內(nèi)流[20]ABA和多胺以外，IAA類、抗氧化酶活性對鉀素吸收的調(diào)控作的產(chǎn)生速率、過氧化氫和MDA的含量顯著增加，SOD、POD的活性均顯著下降[21]；缺鉀減少了對NAD(P)H氧化酶活性的抑制作用，降低了光合作用的電子傳遞，因而可以極大地促進(jìn)ROS的產(chǎn)生缺鉀處理使玉米幼苗的POD活性、葉綠素和蛋白質(zhì)的含量都降低，但MDA的含量和乙醇酸氧化酶的活性升高。與水稻和玉米相似，缺鉀處理也提高了大豆葉片MAD和過氧化氫的含量增加了葉片的電導(dǎo)度但卻提高了抗氧化酶如SOD、POD和CAT的活性。這些結(jié)果表明，盡管缺鉀處理時植物葉片的抗氧化酶活性的變化不盡相同，但ROS、MDA含量或者電導(dǎo)度的增加，意味著植物細(xì)胞的膜系統(tǒng)由于缺鐘 材料與方供試的2種玉米品種為：958和浚單20。958是典型的抗性好，結(jié)實2014518日在西北農(nóng)林科技大學(xué)北校標(biāo)本園大棚進(jìn)行。播浸濕（本實驗選用的營養(yǎng)液為改良后的營養(yǎng)液。播種深度約5cm，每盆種兩粒515%PEG-600036下共放入密封袋中將根剪下共四個裝入一個密封袋中放入液氮內(nèi)速凍便之后測定抗氧化酶活性。試驗進(jìn)201465日進(jìn)行干旱處理，分別于、、、、、日取樣測定植株株高與根長，分別于、、、、日測定地上部干物質(zhì)重與根部重量。2014618，192014年8月29日，將密封袋中的干樣取出，每個處理約取5g，在研缽中分三次共201491，2，3IAA，GA，ZR，ABA2014910MDA2014917SOD測試項目及方IAA，GA，ZR，ABA含量測定方法：酶聯(lián)免疫試劑盒（購自中國作物化MDASODNBT數(shù)據(jù)分SPSSOrigin結(jié)果與分由表3-13-1IAA3.1可以看到，干旱脅迫下，IAA含量明顯低于正常情況。但隨著鉀濃度的增加，干旱脅IAAIAA含量高于抗旱性弱的品：GA作為植物生長的必需激一調(diào)控植物生長發(fā)育的各個方面如萌發(fā)，3.2可以看到，干旱脅迫下，GA含量明顯低于正常情況，且抗旱GA含量低于抗旱性弱的品種。：3.3可以看到，在干旱脅迫下，ZR含量明顯低于正常情況。但同一品種在干旱脅迫時，高鉀處理的玉米ZRZR含量沒有明顯差異。ABA是一種有效的生長抑制劑，能抑制整株植物或離體的生長。ABA制胚芽鞘，莖，根和下胚軸等其他伸長生長。從圖3.4可以看到，隨著鉀濃度ABA含量呈下降趨勢。同一品種在干旱脅迫下，ABA含量明顯高于正常情況，且鉀濃度與ABA含量呈正相關(guān)。不同品種間ABA含量也有較大差異，抗旱性強(qiáng)的品ABA含量低于抗旱性弱的品種。干旱條件下植物體內(nèi)活性氧積累導(dǎo)致膜質(zhì)過氧化而引起膜的，而活性氧的積累（MDA趨勢，兩個品種葉片MDA含量呈曲線變化（如圖3.5。在干旱處理前四天，葉片MDA到破壞，植物受到氧化脅迫。但正常水分處理情況下，MDA含量不隨鉀濃度變化而變MDA活性與品種的抗旱性呈正相關(guān)，可以作為鑒定玉米抗旱性的指標(biāo)。利于消除氧自由基，減輕干旱脅迫對細(xì)胞膜的，從而提高植物的抗旱能力。3.6SOD活性的調(diào)節(jié)，有利于消除活性氧自由基，減輕了干旱脅迫對分處理情況下，SOD,干旱脅迫下兩個不同耐旱性玉米自交系苗期生長發(fā)育及生理生化特性的差異.沈陽崔華威,低溫干旱脅迫對煙草發(fā)芽和幼苗生長的影響及提高其抗寒抗旱性的研究.浙江大學(xué),干旱脅迫對小麥苗期生長的影響及其生理機(jī)制.2009,魏永勝,干旱脅迫和不同土壤鉀水平下煙草植株鉀的分布及其抗旱性研究.2001,西北農(nóng)林Satoshi,Y.,etal.,Simultaneouscrystallizationofphosphateandpotassiumasmagnesiumpotassiumphosphateusingbubblecolumnreactorwithdraughttube.JournalofEnvironmentalChemicalEngineering,2013.1(4).,氮鉀營養(yǎng)對菠菜生長、硝酸鹽累積的影響及機(jī)理研究.2002,浙江大學(xué)唐浩,小麥和玉米生長過程中氮鉀水互作效應(yīng)研究.2008,中國農(nóng)業(yè),擴(kuò)展蛋白與植物激素調(diào)節(jié)的干旱脅迫下小麥細(xì)胞生長的關(guān)系研究.2011,山東農(nóng)業(yè)大學(xué),Cd對玉米生理生化特性及土壤微生物和酶活性的影響2014,西南大學(xué),外源過氧化氫對干旱脅迫下兩種生態(tài)型黃瓜葉片抗氧化酶與DNA甲基化的影響2010,山東,干旱對玉米光合生理及相關(guān)酶表達(dá)的影響.2014,石河子大學(xué)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).,外源激素對茶樹菇液體培養(yǎng)胞外酶活性影響的研究.2008,西南大學(xué)N,M.J.andS.B.H,Growthhormoneregulationofhepaticdrug-metabolizingenzymesintheBiochemicalpharmacology,1989.,鉀營養(yǎng)與激素調(diào)控對水培棉花生長發(fā)育與生理特性的影響.2008,周繼華,外源激素GA_3與ABA對煙草株高及煙草葉片含鉀量的影響.2009,金維環(huán),轉(zhuǎn)EdHP1（氫離子焦磷酸化酶）煙草促進(jìn)磷、鉀吸收的生理機(jī)制及調(diào)控機(jī)制的研究.2010,西北農(nóng)林科技大學(xué).,缺鉀對水稻葉片光合特性、抗氧化酶的影響及其誘導(dǎo)早衰機(jī)制的研究2006,浙江大學(xué)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“l(fā)uxuryconsumption”intermsofKinHebei;i.e.MTJdidnotincreaselintyield,butimprovedKuptake.Ingeneral,K“l(fā)uxuryconsumption”happedunderahighsoilavailableK,andisalsoinfluencedbysoilmoisture,levelofothercationelementsinsoil,andgrowthstatusofnts(Hommelsetal.,1989).Inthepresentstudy,thesoilavailableKinHebeiisashighas170mg/kgaround(Table1),whichistheprerequisitefor“l(fā)uxuryconsumption”ofMTJtreatment.Inaddition,thepromotedrootgrowthandincreasednutrientsuptakefromsoilbyMTJapplication(Tianetal.,2006b)maycontributetotheK“l(fā)uxuryconsumption”ofcottonnts.ThepositiveeffectofPGRsonKuptakeandKuseefficiencyofcottondidnotvarywithlintyieldlevelsThereweregreatdifferencesinlintyieldbetweenBeijingsiteandHebeisiteinthepresentstudy.TheaveragelintyieldinBeijingacrossyears,cultivars,KfertilizersandPGRswas738kgha?1,beingonlyequivalentto56%ofthatinHebei.ThereasonsforloweryieldinBeijingarethatthesoilfertilityispoor(seeaboveinSection4.1)andthecumulativeheatunit(15.5?Cbase)islessthanthatinHebei(1185vs.1284degree-daysin2010;1150vs.1260degree-daysin2011).Doesalowlintyieldaffecttherel