不同小麦品种吸收利用氮素效率的差异及有关机理研究：I.吸收？…

用盆栽试验研究了１２个冬小麦品种在低、高氮条件下的籽粒产量差异,及吸收和利用氮素的效率对其影响。结果证明在低氮处理中吸收效率和利用效率（ＵｔＥＧ）的共同影响导致了产量差异,但利用效率的影响更大;高氮处理则主要是吸收效率的影响,利用效率的影响较小。研究还发现能高效吸收或利用氮素的品种多为矮秆品种,因此高产品种多为矮秆。在低氮处理中的高产品种具有高效吸收或高效利用的特点;高氮处理中的高产品种主要具有高     

不同小麦品种氮效率和产量性状的研究

对29个冬小麦品种进行子粒产量和氮效率的研究,结果表明,在氮胁迫条件下,供试小麦品种的子粒产量具有明显差异。缺氮条件下子粒产量的聚类分析结果表明,供试品种可划分为氮高效、中效和低效三类,氮高效品种在其中所占比例较少。在缺氮条件（N-）下,不同氮效率品种成熟期植株全氮含量差异不大,植株氮素积累量、氮效率（NUE）、吸收效率（UPE）和利用效率（UTE）均以氮高效品种最高,中效品种次之,低效品种最低。缺氮条件下较强的氮索吸收和利用能力是氮高效小麦品种氮胁迫条件下高氮效率的主要原因。     

氮肥处理对氮素高效吸收水稻根系性状及氮肥利用率的影响

2011—2012年在土培条件下,以氮素吸收效率差异较大的15个常规籼稻为供试材料,研究氮肥运筹对不同氮效率品种根系性状、成熟期吸氮量及氮肥利用率的影响,分析影响氮高效水稻氮素吸收的主要根系性状。结果表明:(1)各氮肥处理下,成熟期吸氮量均表现为氮高效品种氮中效品种氮低效品种。适量增施氮肥及基肥+促花肥处理有利于氮高效品种吸氮量的增加,氮素吸收受品种、氮肥处理的显著影响。(2)在施氮量处理下,氮高效品种单株不定根数、单株根干重、单株不定根总长大或较大,单株根活力在常氮(N2)、高氮(N3)处理下有一定的优势;在施氮时期处理下,氮高效品种单株不定根数、单株不定根总长、单株根干重、单株根系总吸收面积、单株根系活跃吸收面积、抽穗期冠根比多数处理有优势;增施氮肥有利于促进氮高效品种单株不定根总长和单株根活力的提高,适量施氮有利于单株不定根数、单株根干重增加,前期施氮可促进不定根的发生和伸长,后期施氮有利于不定根的充实和根系生理性状的提高。此外,增施氮肥可提高各类品种冠根比;(3)在常氮、高氮处理下,氮高效品种氮肥利用率大于氮中效、氮低效品种。(4)提高单株不定根数、单株不定根总长、单株根活力及抽穗期冠根比有利于各类品种吸氮量的提高,增加根干重对氮高效品种吸氮量的提高也有显著的促进作用。结合相关分析与通径分析结果,抽穗期冠根比及单株不定根数、单株根活力、单株不定根总长、单株根干重是影响氮高效品种吸氮能力的主要根系性状。     

夏闲期地表覆盖对旱地土壤水分、小麦氮素吸收运转及产量的影响与施氮调控

为提高旱作麦区土壤水分贮备能力,并探明此基础上提高产量的适宜施氮水平,本文采用大田试验在山西农业大学闻喜试验基地研究了夏闲期覆盖与不覆盖条件下75、150、225 kg·hm-23个施氮量对旱地土壤水分、小麦氮素吸收运转及产量的影响。结果表明:夏闲期深翻覆盖后,播种前0~300 cm土层土壤蓄水量提高约70~80 mm,尤其是80cm以下土层;成熟期0~300 cm各土层土壤蓄水量均低于播种前,尤其是0~160 cm各土层低20~30 mm;各生育期群体茎数、穗数提高,且低、高氮条件下处理间差异显著,小麦总耗水量提高5.68~31.30 mm,产量提高1.43%~7.16%,水分利用效率提高1.27%~4.23%;各生育时期植株氮素积累量、花前氮素运转量和花后氮素积累量提高,且各生育时期植株氮素积累量处理间差异显著,氮肥农学效率提高0.47~1.24 kg·kg-1,氮肥当季回收率显著提高3.01%~4.96%;覆盖配施氮肥后,成熟期0~160 cm土层土壤蓄水量、总耗水量以施氮量150 kg·hm-2最低;各生育期群体茎数、产量构成因素、产量和水分利用效率以施氮量150 kg·hm-2显著最高,75 kg·hm-2最低,且中氮较低氮与高氮处理产量分别提高574.75和341.14 kg·hm-2,水分利用效率提高12.89%和7.77%;各生育时期植株氮素积累量、花前氮素运转量及其对籽粒的贡献率、氮肥农学效率和氮肥当季回收率均以施氮量150 kg·hm-2显著最高,75 kg·hm-2最低,且中氮较低氮与高氮处理氮肥农学效率分别提高1.91 kg·kg-1、3.12 kg·kg-1,氮肥当季回收率提高1.74%和5.32%;此外,产量与穗数的相关性最大(r=0.906),穗粒数居中,千粒重最小;总之,旱地小麦休闲期深翻覆盖有利于蓄水保水,提高底墒,且配施氮量为150 kg·hm-2更有利于水氮互作,促进氮素吸收、运转,达到增产、高效的目的。     

玉米高效吸收氮素的理想根构型

氮肥投入是保证世界粮食总产量不断增加的重要因素. 如何在高投入集约化生产条件下, 提高氮肥利用效率、减少氮肥损失及其带来的环境问题, 是当前作物生产中面临的重要课题. 高产高投入玉米生产体系中, 硝酸盐淋失是氮肥损失的重要途径之一. 本文论述了土壤硝态氮运移特点、玉米吸氮规律及土壤氮素有效性对根系生长的调节作用, 提出了玉米氮高效理想根系构型. 通过改良根系构型、增加深层土壤中根系分布, 有可能减少氮素向深层的淋失, 从而提高氮肥利用率, 同步实现玉米高产与氮高效利用.     

不同小麦品种(系)吸收利用氮素效率的差异及有关机理研究 Ⅲ.影响利用效率的因素分析

用盆栽试验研究了12个冬小麦品种（系）在成熟期以生物学产量为基础的利用效率（UtEB=生物学产量／吸氮量）、收获系数、氮素收获系数和籽粒氮浓度对以籽粒产量为基础的利用效率（UtEG=籽粒产量／吸氮量）的影响。相关分析证明,这4个因子对UtEG的影响各不相同。无论是低氮还是高氮处理,UtEG与UtEB和收获指数呈正相关,而与籽粒氮浓度呈负相关,与氮素收获指数的相关性较差。从相关系数的高低判断,在这名个因子中,籽粒氮浓度对UtEG的影响最大,其次是UtEB和收获指数。虽然氮素收获指数与UtEG的相关性较差,但它在高氮处理的水平较低,致使利用效率（UtEG）降低。此外还分析了开花期单株顶3叶叶绿素含量与利用效率（UtEG和UtEB）的关系。开花期单株顶3叶叶绿素含量与吸氮量的比值（UtEC）因品种（系）而异,且大多数品种（系）的UtEC受供氮水平的影响小,推测该性状可能受遗传控制。相关分析表明,在低氮处理中,UtEC分别与UtEG和UtEB呈显著或极显著正相关,说明UtEC可能是导致品种间利用效率差异的内在因素之一。在高氮处理中,由于叶绿素含量不是光合作用的限制因素,UtEC与UtEG、UtEB相关性较差,对其原因的深入研究,可为采取措施提高高肥条件下的利用效率提供理论依据。     

氮高效利用基因型大麦的物质生产与氮素积累特性

通过土培盆栽试验,研究了22份大麦材料在低氮(125 mg·kg^-1)和正常氮(250 mg·kg^-1)处理下氮素吸收利用效率的基因型差异,探讨氮高效大麦干物质生产与氮素积累特性.结果表明： 大麦氮素吸收利用效率基因型差异显著.低氮处理下籽粒产量、氮素籽粒生产效率及氮素收获指数的最高值分别是最低值的2.87、2.92、2.47倍;氮高效基因型大麦籽粒产量、氮素籽粒生产效率和氮素收获指数均显著大于低效基因型,低氮处理下高效基因型3个参数较低效基因型分别高82.1%、61.5%和50.5%.氮高效基因型大麦各生育期干物质和氮素积累优势明显,干物质积累高峰出现在拔节-抽穗阶段,氮素积累高峰出现在拔节前;低氮处理下高效基因型典型材料DH61、DH121+的干物质量较低效基因型典型材料DH80分别高34.4%、38.3%,氮素积累量较DH80分别高54.8%、58.0%.供试大麦干物质和氮素的阶段性积累量对籽粒产量的影响为拔节前最大,且低氮处理下贡献率最高,分别为47.9%和54.7%;而干物质和氮素的阶段性积累量对氮素籽粒生产效率的影响在抽穗 成熟阶段最大,其次是播种-拔节阶段,低氮处理下这两个阶段的贡献率分别为29.5%、48.7%和29.0%、15.8%.氮高效基因型大麦在各生育期的物质生产和氮素积累能力强,低氮处理下优势较为明显,能够提高拔节前干物质生产和氮素积累能力,并协同提高大麦产量和氮素利用效率.     

高肥力土壤条件下不同基因型花生对氮素利用的差异

在桶栽条件下,利用¹⁵N示踪技术,选用20个基因型花生为供试材料,研究了高肥力土壤条件下不同基因型花生对氮素利用的差异.结果表明:高肥力土壤条件下花生氮素营养以土壤氮为主,根瘤固氮次之,肥料氮最低.不同基因型间花生对全氮、肥料氮、土壤氮和根瘤固氮的吸收和积累均存在显著差异,基因型间遗传变异以根瘤固氮最大,肥料氮和土壤氮相当.氮素荚果生产效率和氮肥利用率基因型间差异显著,最高值分别为最低值的3.6和2.1倍.全氮、肥料氮、土壤氮和根瘤固氮的氮素收获指数基因型间均存在显著遗传变异,且以根瘤固氮的氮素收获指数基因型间遗传变异最大.花生荚果产量与不同氮源氮素积累量及氮素收获指数、氮素荚果生产效率和氮肥利用率呈显著或极显著正相关.依据花生对不同氮源氮素吸收积累和荚果产量筛选出全氮高积累高产型、肥料氮高积累高产型、土壤氮高积累高产型和根瘤固氮高积累高产型四大类型花生,其中四大类型特征兼有的有4个花生基因型.     

花期渍水逆境下氮素对油菜产量及氮肥利用效率的影响

温室盆栽试验条件下,设置渍水和对照2个水分处理,每个水分处理下设置3个施氮水平(0.05、0.2、0.3 g N·kg^-1土),研究了花后渍水逆境下氮素营养对两个氮高效基因型‘Monty’、‘湘油15’和两个氮低效基因型‘R210’、‘Bin270’油菜产量、产量性能及氮肥利用效率的影响.结果表明:与对照相比,花后渍水处理显著降低了油菜的单株角果数、千粒重、每角粒数和籽粒产量.在适宜水分条件下,增施氮肥显著增加了油菜籽粒产量,而在渍水逆境处理下,增施氮肥对油菜籽粒产量的形成贡献不大.氮高效基因型较氮低效基因型对花后渍水逆境下的籽粒灌浆充实具有一定的促进作用.在同一水分处理下,花后渍水明显降低了油菜氮肥利用率、氮肥偏生产力、氮肥农学利用率、氮素吸收效率和氮收获指数,渍水显著影响了不同基因型油菜的氮素吸收利用能力,而氮高效基因型在渍水逆境下较氮低效基因型更有利于将氮素转运、再分配到角果中,提高籽粒生产效率.油菜产量性能参数存在显著的水氮互作效应,水分、氮肥及水氮互作对油菜籽粒产量和产量性能参数的影响因基因型的不同而异.     

施氮量对小麦氮磷钾养分吸收利用和产量的影响

高产条件下研究了不同施氮量对小麦植株氮、磷、钾养分吸收利用及籽粒产量的影响.结果表明,适量施氮可促进小麦植株对氮素的吸收与积累,较高的施氮量不利于起身期之后的氮素积累,致使成熟期小麦氮素积累量未能显著提高;与不施氮肥相比,施氮显著提高植株磷素积累量;随施氮量增加,植株磷素积累量增加不显著;施氮量增加促进小麦生育前期对钾素的吸收积累,在生育后期降低植株钾素的流失.随施氮量增加,籽粒氮素含量呈先增后降的趋势,氮素向籽粒的分配比例趋于降低,植株氮素利用效率无显著变化,氮素收获指数下降;不同施氮处理之间籽粒磷素含量和钾素含量无显著差异,施氮量增加,营养器官钾素含量、钾素积累量和钾素向叶片的分配比例均呈增加趋势;同时,磷素和钾素利用效率降低;不同施氮处理间,植株磷素、钾素收获指数无显著差异.籽粒产量随施氮量增加呈先增加后降低的趋势,以施氮195 kg/hm2的处理籽粒产量最高.     

Genotypic variability for physiological efficiency index of nitrogen in oats

One of the methods for measuring the efficiency of N utilization by plants is the index of physiological efficiency of absorbed N (PEN) which for cereals is defined as the ratio of grain produced to the total N absorbed by the above-ground plant parts (grain and straw) at maturity. This index indicates how this absorbed N is used by the plant to produce grain. The objective of this work was to study the genotypic variability of PEN in oats (Avena sativa L.) and to what extent grain yield is related to PEN. Seven selected oat genotypes were studied under greenhouse conditions with 5 levels of added N including control (no additional N). At maturity the grain and straw were harvested separately and analyzed for total N. The results show that there was a highly significant variation among genotypes in both yield per pot and PEN. Grain yield was positively and significantly related to PEN (r=0.95^xx). The total N absorbed by plants was much less correlated with grain yield than PEN. The results suggest that PEN may be used in a plant breeding program to detect the potentially high yielding oat genotypes and to evaluate those capable of exploiting N input most efficiently.     

Effect of N fertilizer rate and soil pH on N efficiency in corn

Nitrogen (N) efficiency components and N accumulation parameters were determined for seven commercially available corn (Zea mays L.) hybrids grown on a Cecil sandy loam soil (Typic Hapludult) in the Southeasten U.S. The hybrids were grown in field plots at three soil pH levels (4.8, 5.5, and 6.6) and four N fertilizer rates (0.4, 1.8, 3.2, and 6.0, g plant⁻¹). Nitrogen uilitzation efficiency (grain yield/total N uptake) was significantly different among hybrids in both 1983 and 1984. Differences in N use efficiency (grain yield/N supply) and N uptake efficiency (total N uptake/N supply) ranged from 100.4 to 114.6 and from 1.62 to 1.90, respectively, in 1984. Nitrogen fertilizer rate significantly affected all measured N accumulation and efficiency parameters except N uptake after silking in 1983. The results indicate that improving N uptake or soil N availability might increase grain yields for hybrids with higher N utilization efficiency.     

Variation in nitrogen use efficiency among soft red winter wheat genotypes

Summary Nitrogen use efficiency (NUE), defined as grain dry weight or grain nitrogen as a function of N supply, was evaluated in 25 soft red winter wheat genotypes for two years at one location. Significant genotypic variation was observed for NUE, nitrogen harvest index, and grain yield. Genotype x environment interaction for these traits was not significant. Several variables including N uptake efficiency (total plant N as a function of N supply), grain harvest index, and N concentration at maturity were evaluated for their role in determining differences in NUE. Nitrogen uptake efficiency accounted for 54% of the genotypic variation in NUE for yield and 72% of the genotypic variation in NUE for protein. A path coefficient analysis revealed that the direct effect of uptake efficiency on NUE was high relative to indirect effects.The investigation reported in this paper (No. 85-3-122) is in connection with a project of the Kentucky Agricultural Experiment Station and is published with approval of the Director     

Comparative response of wheat and oilseed rape to nitrogen supply: absorption and utilisation efficiency of radiation and nitrogen during the reproductive stages determining yield

We investigated the response of spring wheat and oilseed rape to nitrogen (N) supply, focusing on the critical period for grain number definition and grain filling. Crops were grown in containers under a shelter and treated with five combinations of applied N. Wheat and oilseed rape produced comparable amounts of biomass and yield when corrected for the costs of biomass synthesis (SC). From the responses of biomass and yield to late N applications and the apparent contribution of mobilised biomass to yield, it seems that the yield of oilseed rape was more source-limited during grain filling than that of wheat, particularly at the medium and high N levels. Both species recovered equal amounts of N from the total available N in the soil and had similar N use efficiencies, expressed as yield per unit of N absorbed. However, oilseed rape had higher efficiency to convert absorbed N in biomass, but lower harvest index of N than wheat. Oilseed rape had similar or lower root biomass than wheat, depending on N level, but higher root length per unit soil volume and specific root length. The specific uptake rate of N per unit root dry weight during the critical period for grain number determination was higher in oilseed rape than in wheat. In wheat, N limitation affected growth through a similar or lower reduction in radiation use efficiency corrected for synthesis costs (RUE_SC) than in the cumulative amount of intercepted photosynthetically active radiation (IPARc). In oilseed rape, lower growth due to N shortage was associated more with RUE_SC than IPARc, during flowering while during grain filling both components contributed similarly to decreased growth. RUE_SC and the concentration of N in leaves and inflorescence (LIN%) decreased from flowering to maturity and were curvilinearly related. Oilseed rape tended to have higher RUE_SC than wheat at high N supply during the critical period for grain number determination, and generally lower during grain filling. The reasons for these differences and possibilities to increase yield potential are discussed in terms of the photosynthetic efficiency of the different organs and changes in source–sink ratio during reproductive stages. This revised version was published online in June 2006 with corrections to the Cover Date.     

Water and Nutrient Use Efficiency in Diploid, Tetraploid and Hexaploid Wheats

Three diploid (Triticum boeoticum, AA; Aegilops speltoides, BB and Ae. tauschii, DD), two tetraplold (T. dlcoccoides,AABB and T. dicoccon, AABB) and one hexaploid (T. vulgare, AABBDD) varieties of wheat, which are very important in the evolution of wheat were chosen in this study. A pot experiment was carried out on the wheat under different water and nutrient conditions (i) to understand the differences in biomass, yield, water use efficiency (WUE), and nutrient (N, P and K) use efficiency (uptake and utilization efficiency) among ploldles in the evolution of wheat; (ii) to clarify the effect of water and nutrient conditions on water and nutrient use efficiency; and (iii) to assess the relationship of water and nutrient use efficiency in the evolution of wheat. Our results showed that from diploid to tetraploid then to hexaploid during the evolution of wheat, both root biomass and above-ground biomass increased initially and then decreased. Water consumption for transpiration decreased remarkably, correlating with the decline of the growth period, while grain yield, harvest index, WUE, N, P and K uptake efficiency, and N, P and K utilization efficiency increased significantly. Grain yield, harvest index and WUE decreased in the same order: T.vulgare ＞ T. dicoccon ＞ T. dicoccoides ＞ Ae. tauschii ＞ Ae. speltoides ＞ T. boeoticum. Water stress significantly decreased root biomass, above-ground biomass, yield, and water consumption for transpiration by 47-52%, butremarkably increased WUE. Increasing the nutrient supply increased wheat above-ground biomass, grain yield,harvest index, water consumption for transpiration and WUE under different water levels, but reduced root biomass under drought conditions. Generally, water stress and low nutrient supply resulted in the lower nutrientuptake efficiency of wheat. However, water and nutrient application had no significant effects on nutrient utilization efficiency, suggesting that wheat nutrient utilization efficiency is mainly controlled by genotypes. Compared to theother two diploid wheats, Ae. squarrosa (DD) had significant higher WUE and nutrient utilization efficiency, Indicating that the D genome may carry genes controlling high efficient utilization of water and nutrient. Significant relationships were found between WUE and N, P and K utilization efficiency.     

高产磷高效水稻磷素吸收利用特征

通过正常供磷的大田试验（2011年）,以产量和磷籽粒生产效率为指标,将27份中熟水稻亲本材料划分为4个类型,再通过正常和低磷处理的土培试验（2012年）,筛选出高产磷高效水稻材料,并探讨各种磷效率对产量的贡献率.结果表明： 结合两年的试验结果,供试材料的产量和磷利用效率均存在显著的基因型差异,筛选出GR泸17/矮TTP//泸17_2（QR20）为高产磷高效材料.在两个供磷水平下,QR20的产量和磷利用效率均显著高于低产磷低效材料玉香B,其产量分别是玉香B的1.96和1.92倍.大田和土培试验结果均表明,磷积累量对产量的贡献率均高于磷籽粒生产效率和磷收获指数.正常供磷条件下,磷积累量和磷籽粒生产效率对产量的贡献率差异不大,低磷条件下差异较大（66.5%和26.6%）,磷收获指数对产量的贡献率最低,最高仅为11.8%（土培）.土培试验中,正常供磷条件下,拔节-抽穗阶段的磷积累量对产量和磷收获指数的贡献率最高,分别为93.4%和85.7%,对磷籽粒生产效率的贡献率为41.8%;在低磷条件下,分蘖-拔节阶段的磷积累量对产量和磷籽粒生产效率的贡献率最高,分别为56.9%和20.1%,对磷收获指数的贡献率为16.0%.土培正常供磷条件下,水稻QR20的产量、磷积累量和磷收获指数相对于低磷处理分别增加了20.6%、18.1%和18.2%,差异显著.综上,磷效率对水稻产量的贡献率大小依次为磷吸收效率＞利用效率＞转运效率;正常供磷条件下,拔节-抽穗阶段的磷积累量对产量的贡献率最高,低磷胁迫下,分蘖-拔节阶段的磷积累量对产量的贡献率最高,这两个阶段可能是水稻高产磷高效协调统一的关键时期.
     

Genotypic differences in nitrogen efficiency of white cabbage (Brassica oleracea L.)

In vegetable production, N balance surpluses are especially high which increases the risk of environmental pollution. The cultivation of N-efficient cultivars may contribute to alleviate the problem. A 2-year field experiment was conducted with eight white cabbage cultivars of three different maturity groups at two N fertilization levels. Genotypes differed both in N efficiency (head fresh weight at low N supply) and in yield at high N supply. These differences were not related to N uptake but to N utilization efficiency. At low N supply, harvest index was the main determining factor for genotypic yield differences. For earlier maturing cultivars a slower leaf emergence was responsible for the low harvest index. The response of the cultivars to low N supply was dependent on the weather conditions, particularly temperature, (highly significant year × cultivar × N supply interaction) at early growing stages. This suggests that breeding of cultivars with generally low-temperature tolerance could contribute to enhancing N utilization. Especially at high N supply, a high N harvest index was important for yield formation due to its effect on head water accumulation. For late cultivars, a high N retranslocation from leaves to the heads was related to yield both at low and high N supply. The study suggests that breeding of N-efficient cultivars may reduce N release to the environment by reducing the necessary N input and reducing the N content remaining in the crop residues.     

Leaf senescence and N uptake parameters as selection traits for nitrogen efficiency of oilseed rape cultivars

The cultivation of N-efficient oilseed rape cultivars could contribute to a reduction of the large N balance surpluses of this crop. To facilitate the breeding process of N-efficient cultivars, the identification of secondary plant traits correlating with N efficiency is necessary. The objectives of this study were to investigate leaf senescence and N uptake parameters of oilseed rape cultivars and doubled haploid (DH) lines with contrasting N efficiency in a short-term nutrient solution experiment and to relate these results to their performance in field experiments. In the nutrient solution experiment, genotypes differed in leaf senescence of fully expanded leaves and maximum N uptake rate per unit root length under low N supply. A high maximum N uptake rate seemed to have contributed to delayed leaf senescence by enhancing N accumulation in leaves. Also in the field experiments, genotypes differed in leaf senescence after flowering at limiting N supply. Additionally, the most N-efficient DH line was able to adapt leaf photosynthetic capacity to the low-light conditions in the canopy during flowering. N efficiency (grain yield at limiting N supply) was positively correlated with delayed leaf senescence both in nutrient solution and field experiments. It is concluded that important leaf and root traits of N-efficient cultivars are expressed in short-term nutrient solution experiments, which may facilitate the selection of N-efficient cultivars.