氮水供应对玉米根系形态特征及生理特性的影响

氮水供应对玉米根系形态特征及生理特性的影响EffectsofNitrogenandWaterSupplyonRootMorphologicalandPhysiologicalCharacteristicsinMaize摘要探究氮水供应对“红单3号”玉米根系的影响。通过盆栽方式，两因素完全随机试验设计，氮素分别为低氮(15g/m2)、中氮（30g/m2）、高氮（45g/m2）3个水平；水分分别是供水充足（620mm）和供水不足（310mm）2个水平，共6个处理，3次重复。结果表明：氮水供应对根系形态特征及生理特性影响不同。其中不同氮素水平下，根长在各个生育期差异显著，主要表现为低氮中氮高氮；根条数主要表现为高氮中氮低氮；根体积和根系干物质积累主要表现为中氮高氮低氮；根系活力在三叶期和开花期较高。而开花期后又分别减少，减少幅度由大到小的顺序为低氮高氮中氮。不同水分水平下，根长、根条数、根体积和根鲜重在各个生育期差异显著，主要表现为供水充足供水不足；根干物质积累在各个生育期差异不显著，主要表现为供水不足供水充足；根系活力在三叶期和开花期较高。而开花期后又分别减少，减少幅度由大到小的顺序为供水充足供水不足。关键词：氮水供应；根系；形态特征；生理特性ABSTRACTInordertoexploretheeffectsofnitrogenandwatersupplyontheHongdanN0.3cornroot.Throughflowerpotcultureexperiment,twofactorscompletelyrandomizedtrialdesign,Havinglownitrogen(15g/m2)andmiddlenitrogen(30g/m2),highnitrogen(45g/m2)3levels;waterissufficientwatersupply(620mm)andinadequatewatersupply(310mm)on2levels,atotalof6treatment,repeat3times.Theresultsshowthat:thenitrogenwatersupplyonrootmorphologicalcharacteristicsandphysiologicalcharacteristicsofdifferent.Thedifferentnitrogenlevels,rootlengthineachgrowingperioddifference,mainshowislowNisbetterthanmiddleNandhighN;rootnumbermainlyforhighNisbetterthanmiddleNandlowN;therootvolumeandrootdrymatteraccumulationmainlyformiddleNisbetterthanhighNandlowN;rootactivityinblossomandthreeleavesperiodthehigherstageof.Theblossomperiodandwerereduced,toreducethemagnitudeofasequencefrombigtosmallforlowNisbetterthanhighNandmiddleN.Fordifferentwaterlevel,rootlength,rootnumber,rootvolumeandrootfreshagainineachgrowingperiod,differencemainshowisasufficientwatersupplyisbetterthanwatersupplyshortage;rootdrymatteraccumulationinthewholegrowthperiodofnosignificantdifference,mainshowisinsufficientwatersupplyisbetterthanadequatewatersupply;rootactivityinthreeleavesandblossomperiodthehigherstageof.Theblossomperiodandwerereduced,toreducethemagnitudeofasequencefrombigtosmallenoughforwatersupplyisbetterthanwatersupplyshortage.Keywords:NitrogenandWaterSupplying;RootSystem;MorphologicalCha-racteristics;PhysiologicalCharacteristicsIII目录1.前言.............................................................................................................................11.1玉米根系与地上部分的相关性..............................................................................11.2水分对玉米根系的影响..........................................................................................11.3氮肥对玉米根系的影响..........................................................................................11.4氮水供应对玉米根系的影响..................................................................................22.材料与方法.................................................................................................................32.1材料..........................................................................................................................32.2试验方法..................................................................................................................32.3测定指标及方法......................................................................................................33.结果与分析.................................................................................................................53.1氮水供应对玉米根长的影响..................................................................................53.2氮水供应对玉米根条数的影响..............................................................................63.3氮水供应对玉米根体积的影响..............................................................................73.4氮水供应对玉米根鲜重的影响..............................................................................83.5氮水供应根干物质积累的影响............................................................................103.6氮水供应对玉米根系活力的影响........................................................................114.讨论...........................................................................................................................144.1氮水供应对玉米地下部分形态的影响................................................................144.2氮水供应对玉米地下部分生理特征的影响........................................................145.结论...........................................................................................................................16参考文献......................................................................................................................17致谢..........................................................................................................................1911.前言根系是作物重要吸收、合成、固定和支持器官，土壤中水分和养分主要通过作物根系被吸收，根系发育状况直接影响着作物对水分和养分的利用；另一方面由于根系生长具有“趋水性”和“趋肥性”，土壤水分和养分对根系生长又具有“可塑性”，了解土壤水分、养分和根系生长的这种互馈关系对高效利用水肥资源有十分重要的意义[1]。水分和氮素调控是玉米高产优质栽培技术体系的重要组成部分[2]。不同土壤水分条件下氮肥对根系生长的影响尚少见报道。1.1玉米根系与地上部分的相关性根冠比是根系与地上部干物质积累关系的具体反映，生育前期根冠比数值较高，而后保持在一定水平，到灌浆期根冠比下降迅速[3.4]。整个生育期内玉米根系生物量与地上部生物量呈极显著正相关[5]。1.2水分对玉米根系的影响根系是作物感受土壤干旱的原初部位，水分胁迫时光合产物优先向根系转移，增加了根系生长量，提高了根冠比[6]。根系与耐旱性关系十分密切[7]，不同时期发生的干旱胁迫均对根系产生伤害，其生长明显受到抑制，表现出适应性变化和对干旱胁迫的抗性，根系质膜透性上升，根系活力下降，并且，下部幼根的质膜透性比上部老根上升快，同时其活力下降也快于上部老根[8]。干旱胁迫下玉米叶片和根系脂质过氧化作用增强根系和叶片中的游离脯氨酸含量升高[9]。苗期所受干旱的伤害程度低于拔节期，而且不同抗旱能力的品种在形态上所受抑制和发生的适应性变化也不同[10]。1.3氮肥对玉米根系的