【作者】 武文明；

【导师】 李金才；

【作者基本信息】 安徽农业大学 ， 作物栽培学与耕作学， 2013， 博士

【摘要】 长期以来，由于沿淮地区洪涝灾害频繁，降水量主要集中在夏季，6~9月降水量约占年降水量的50%~80%，而这一时期正是主要作物适时收获、播种和生长的关键时期，易造成作物减产或绝收，给当地农村带来巨大损失。沿淮地区发生洪涝危害的主要作物为小麦、水稻、玉米，影响了沿淮地区粮食生产潜力的发挥。如何提高沿淮地区粮食生产能力，减轻渍害对小麦、玉米生产所造成的危害，关系安徽省和全国粮食产业的发展。本文在沿淮地区小麦-玉米连作模式下，通过两年大田试验，系统研究了渍害和不同氮肥运筹方式对小麦-玉米生理生态效应的影响；渍害模式下不同氮肥运筹方式对小麦-玉米的恢复生长的补偿效应。探讨适宜沿淮地区小麦-玉米生产的氮肥运筹方式，以期为沿淮地区小麦-玉米高效栽培提供理论依据和实践尝试。主要研究结果和结论如下：1渍害对冬小麦生理生态特性和产量的影响及氮素调控(1)孕穗期渍害显著降低旗叶叶绿素含量、Fv/Fo、Fv/Fm、qP、PSII、ETRmax、和Ek。氮肥后移显著提高叶绿素含量和叶绿素荧光各参数。叶绿素含量与Fv/Fm、qP和PSII呈显著正相关，与NPQ呈显著负相关。渍害下氮肥的补偿效应较正常供水明显。氮肥后移运筹方式显著减轻渍害对光合器官的破坏，使小麦生育后期功能叶具有较强的光捕获能力和光化学效率，改善了旗叶光合性能。(2)孕穗期渍害显著降低小麦植株各器官氮素含量，同时降低开花前氮素的转运率。氮肥后移技术提高单茎氮素积累量和花前氮素转运率，表明氮肥后移技术能够弥补渍水逆境导致的氮素流失，保证小麦生育后期足够的氮素供应量。(3)孕穗期渍害缩短籽粒灌浆期、降低籽粒灌浆速率；氮肥后移使灌浆期延长，平均灌浆速率提高，从而较氮肥前移显著提高小麦千粒重，弥补渍害对小麦的影响。不同粒位和不同穗位籽粒灌浆特性表明，第一粒位最大潜力势K低于第二粒位。主茎穗、第一分蘖穗和第二分蘖穗的第一和第二粒位籽粒最大潜力势也表现为主茎穗>第一分蘖>第二分蘖。(4)孕穗期渍害对分蘖穗结实特性影响大于主茎穗，渍害显著增加不孕小穗数，降低结实小穗数。孕穗期渍害显著降低主茎穗结实4粒的小穗数比例和分蘖穗结实3、4粒小穗数的比例及第3、4粒位籽粒粒重和第3、4粒位粒重对单穗粒重的贡献率。氮肥前移增加不孕小穗数，降低结实小穗数和结实粒数。氮肥后移显著提高孕穗期受渍小麦主茎、分蘖穗结实小穗数和粒重，增加主茎和分蘖穗结实3、4粒小穗的比例和结实小穗第3、4粒位的粒重，提高第3、4粒位粒重对单穗粒重的贡献率，减少不孕小穗数，进而较氮肥前移处理显著提高经济产量。氮肥后移运筹方式有利于减轻孕穗期渍害对小麦穗部结实特性的影响。2渍害对夏玉米生理生态特性和产量的影响及氮素调控(1)苗期渍害降低群体叶面积系数(LAI)，造成玉米生长发育受阻，穗下层叶片较早衰老使得群体LAI降低。苗期渍害下营养优先供应穗位叶片的生长以保证光合产物向籽粒的供应和转运。氮肥后移能够通过增大穗位层和穗上层叶片的LAI来弥补穗下层LAI降低导致的群体LAI降低的趋势，且弥补的效应大于渍害导致穗下层LAI降低的效应，进而使得苗期渍害下氮肥后移的群体LAI较氮肥前移增大。(2)苗期渍害显著降低叶绿素含量和叶绿素a/b比率，Fv/Fm、qP、 PSII、P%、ETRmax、和Ek；增大NPQ、D%和X%。渍害使得穗下层叶片Fv/Fm降幅最大，上部叶片的次之，中部叶片降幅最小；氮肥后移能够通过提高穗位层叶绿素含量，达到弥补叶绿素各荧光参数下降的趋势，起到补偿效应。(3)苗期渍害降低玉米植株各器官氮素积累量，增大茎部氮素转运率。苗期渍害导致穗位层的叶片氮素向籽粒转运量和转运率增高，从而导致穗位叶片的早衰。氮肥后移可以提高苗期渍害玉米各器官氮素的累积量，适当提高穗上层、穗下层转运率，降低穗位层氮素转运率，保证玉米生育后期氮素的供应量，提高氮素的吸收利用效率和偏生产力。(4)吐丝后干物质积累量与最终籽粒产量关系密切，苗期渍害显著降低吐丝后群体干物质积累量，氮肥后移促进吐丝后后干物质积累，为提高玉米产量奠定生物量基础。(5)苗期渍害降低籽粒灌浆速率。随着播期推迟，玉米籽粒最大潜力势降低，籽粒灌浆时间缩短，达到最大灌浆速率的时间推迟。苗期渍害降低玉米籽粒最大潜力势（K），较早达到最大灌浆速率（Vm），降低平均灌浆速率（Va）；苗期渍害主要影响快增期和缓增期的Va。氮肥后移技术能够弥补Va和T下降的趋势，是渍水条件下氮肥后移技术较氮肥前移技术玉米粒重提高的主要因素。(6)玉米苗期渍害显著降低玉米籽粒产量，达24.2%~28.8%，粒叶比和收获指数下降，播期越晚渍害对玉米产量的影响越大；氮肥后移可以弥补产量下降的趋势，但播期越晚，氮肥的补偿作用相对削弱。小麦孕穗期渍害和玉米苗期渍害研究结果均表明，渍水条件下采用适当氮肥后移的运筹方式和渍后及时提供氮素营养补偿可明显减轻渍水逆境对小麦、玉米造成的危害。更多还原

【Abstract】 Due to the precipitation is concentrated in the summer season, the precipitationduring June to September accounts for50%~80%of annual precipitation, which results infrequently flooding disaster along the Huaihe River and huge losses to local rural. The flooding disasteraffects the yield increased of wheat, rice and corn, therefore leads to food production potential to playalong Huaihe River.How to improve the production capacity along the area of huaihe River, and reducethe effect of waterlogging on wheat and corn yield are related to the development of national foodindustry. Based on the problems existing in production, the present study was conducted toinvestigate the physiological and ecological effects of different nitrogen fertilization on wheat andcorn under waterlogging environment, to find out the reasonable nitrogen fertilization alongHuaihe River. Thus to provide theoretical and practical basis for realizing mechanization ofthe compensation effect of nitrogen and high-efficiency cultivation of wheat and corn. Themain contents and results are as follows:1Effects of waterlogging stress on eco-physiological characteristics and grain yield of winterwheat and nitrogen regulationTo understand the response of number and weight of grain at different spikeletposition and grain position, chlorophyll fluorescence parameters of wheat flag leaf towaterlogging stress at booting stage and the effect of N fertilization, we carried out a fieldexperiment from autumn of2008to summer of2010using winter wheat cultivar―Wanmai54‖as material. The waterlogging stress was imposed for7d at booting stage. Fournitrogen treatments were designed for waterlogging stress and the control (normal watering)of which N application rate was240kg ha-1in all treatments but with different proportionsat land preparation, jointing, and booting stage (10:0:0for N1,7:3:0for N2,5:5:0for N3,nd3:5:2for N4) the results showed that (1) The maximum chlorophyll content of flagleaves occurred at the booting stage. Under normal watering condition, Fv/Fm, Fv/Fo, andqP showed―high-low‖variation, and the maximum values were observed between May3 and May11. However, under waterlogging stress at booting stage, Fv/Fm, Fv/Fo, and qPshowed "low-high-low" curve. Compared to control treatment, waterlogging at bootingstage significantly decreased Fv/Fm, Fv/Fo, qp, andPSII(P<0.05), and NPQ significantlyincreased (P<0.05). With the delay of nitrogen fertilization, Fv/Fm, Fv/Fo, qP, andPSIIincreased significantly compared to the forward nitrogen fertilization treatments. Postponeof nitrogen supply improved photosynthetic capacity by increasing photosynthetic pigmentcontents, and enhancing photosynthetic efficiency under water deficit. The chlorophyllcontent was positively correlated with Fv/Fm, qP, andPSII(P<0.05), but negativelycorrelated relationship with NPQ (P<0.01). From the chlorophyll fluorescence rapid lightcurves, we found that, compared to normal watering, waterlogging stress at booting stagesignificantly decreased the maximal relative electron transport rate (ETRmax), initial slope(), and half saturation point of light intensity (Ek). Postpone of nitrogen fertilizerapplication alleviated the photodamage to PSΙΙ caused by water stress, and thecompensation effect of late nitrogen fertilization occurred earlier than that of early nitrogenfertilization.(2) Waterlogging stress in the booting stage significantly decreased thenitrogen content of different organs, and decreased translocation of nitrogen stored invegetative organs before anthesis. Postpone of nitrogen application can increase thenitrogen content and translocation rate before anthesis, which resulted in adequate nitrogensupplied in the later stage of wheat.(3) Waterlogging stress decreased filling period, andfilling rate. Postpone of nitrogen application can resulte in longer filling period, highermean filling rate, and ultimately increased1000-grain weight. The research of fillingcharacterics of different grain and spike positon indicated that potential grain weight (K)of1stwas higher than that of2nd, potential grain weight (K)of main stem was higher than1sttiller and2ndtiller.(4) Seed-setting characteristics of main stem were superior to tillerspike. In the N1treatment the sterile spikelet per spike was significantly increased, and thegrain number per spike was significantly decreased. Compared with N4treatment, sterilespikelet per spike of N1treatment increased by25.5%and29.8%in2008-2009and2009-2010growing seasons, respectively. The grain number per spike of N1treatmentdecreased by5.7%. Waterlogging had greater effect on the tiller spike than the main stemspike. Waterlogging at booting stage significantly increased sterile spikelet per spike by10.6%and4.5%, and the grain number per spike decreased by2.8%and1.4%in the twogrowing seasons, especially for spike with four grains on main stem and three grains perspike of tiller spike, the grain weight in the third and the fourth grain positions. With thedelay of nitrogen fertilization, spikelet per spike, single weight per spike increased significantly, the sterile spikelet per spike decreased compared to the prior N fertilizationtreatments. Postponed nitrogen fertilization could compensate the decrease of spike withthree and four grains and increase the grain weight in third and the fourth grain positionsunder waterlogged environment at booting stage, increase the contribution rate of the thirdand the fourth grains weight to the grain weight per spike. Therefore, with the postponednitrogen fertilization, grain yield and spikelet grain number and grain weight at differentspikelet of wheat were enhanced. Results indicate that postponed N fertilization alleviatesthe effect of waterlogging at booting stage on the seed-setting characterisitics of spike andsingle grain weight.2Effects of waterlogging stress on eco-physiological characteristics and grain yield of summermaize and nitrogen regulationTo understand the response of chlorophyll (Chl) fluorescence parameters,photosynthetic pigment contents, leaf area index (LAI), rapid light curve (RLC) and grainyield of maize to waterlogging stress at seedling stage and the effect of N fertilizationregulation, we carried out a field experiment from2009to2011using summer maizecultivar "Zhengdan958" as material. The waterlogging stress was imposed for7d atseedling stage. Four N treatments were designed for waterlogging stress and the control(normal watering) of which N application rate was240kg ha-1in all treatments but withdifferent proportions at land preparation, jointing, and big trumpet stage (10:0:0for N1,7:3:0for N2,5:5:0for N3, nd3:5:2for N4) the results showed that (1) Waterlogging stressin the seedling stage significantly decreased leaf area index (LAI), especially LAI ofunder-ear layer, which resuted in earlier death of leaf. The nutrient element prior to the earlayer leaf under waterlogging stress in order to ensure the photosynthetic product suppliedand translocated to grain. Postpone of nitrogen application can increased the LAI of earlayer and above-ear layer to compensate the decrease of under-ear layer, and thecompensation effect was higher than the decrease effect of waterlogging stress, whichresulted in higher LAI compared to the earlier nitrogen application.(2) Waterlogging stressdecrease the maximal efficiency of PSII photochemistry (Fv/Fm) in dark-adapted leaves.Moreover, the contents of Chl and Chla/b, the actual PSII efficiency (PSII), photochemicalquenching coefficient (qP), and the fraction of light used in PSII photochemistry (P%) alsodropped under waterlogging stress. But non-photochemical quenching (NPQ), thermalenergy dissipation (D%), and excess of energy excitation (X%) showed different responsewhich increased under waterlogging stress. As to different N fertilization, postpone of Nsupply could improve photosynthetic capacity by increasing LAI, Chl contents, and alleviating the photosynthetic efficiency decrease under waterlogging stress. From thechlorophyll fluorescence rapid light curves, The results showed that compared with control,waterlogging stress at seedling stage significantly decreased the maximal relative electrontransport rate (ETRmax), initial slope (), and half saturation point of light intensity (Ek).Postpone of N fertilizer application alleviated the photodamage to PSΙΙ caused bywaterlogging stress, and the compensation effect of late N fertilization occurred earlierthan that of early N fertilization. Photosynthetic characters of maize under waterloggingstress at seedling stage exhibited positive responses to N supply which indicates thatpostpone of N fertilizer supply is recommended to improve photosynthetic efficiency andalleviate photodamage under waterlogging stress at seedling stage.(3) Waterlogging stressin the seedling stage can significantly decreased nitrogen accumulation of different organsand can increase the nitrogen translocation of stem, which also can increase the nitrogentranslocation of ear layer leaf and resulted in earlier death of ear layer leaf. Postpone ofnitrogen application can increase the nitrogen content of different organs, nitrogentranslocation of under-ear layer and above-ear layer leaf and decrease the translocation ofear layer leaf, which resulted in adequate nitrogen in the later stage of maize and increasedthe nitrogen uptake efficiency and partial factor productivity from applied nitrogen.(4)The dry matter accumulation after flowering stage is close to the grain yield. Waterloggingstress in the seedling stage can significantly decreased the dry matter accumulation afterflowering stage. Postpone of nitrogen application can enhance the accumulation of drymatter and lay the foundation for increased grain yield.(5) Waterlogging stress in theseedling stage decreased filling rate. With the postpone of planting data, the potential grainweight (K) decreased, the filling period decreased. Waterlogging stress decreased K andaverage filling rate (Va), and earlier reached the maximum filling rate (Vm), which maininfluence the Vaof fast filling stage and slow filling stage. Postpone of nitrogen applicationcan compensate the decrease of Vaand filling period (T).(6) Waterlogging stress in theseedling stage significantly decreased grain yield of about24.2%~28.8%, grain/leaves andharvest index decreased. The influence of waterlogging stress enhanced with postpone ofplating date. Postpone of nitrogen application can compensate the decrease trendecny ofgrain yield, but the compensate effect weakened with postpone of plating dateAll the resultes indicated that proper postpone of nitrogen application underwaterlogging stress or supply nitrogen timely after waterlogging stress can alleviate theeffect of waterlogging stress on wheat and maize.更多还原