小麦氮素营养与籽粒灌浆期氮素转移的研究进展

对小麦氮素营养与籽粒灌浆期氮素转移研究进展进行了综述。过去进行的大量研究结果表明,小麦籽粒最终累积的氮素有相当一部分来自于灌浆期间营养器官中氮素的再转移,来自营养器官氮(内源氮)与土壤中新吸收氮(外源氮)的比例基本上是1:2。因此,花后营养器官氮素营养水平是决定小麦籽粒产量、籽粒中氮素累积量和蛋白质含量的一个重要因素。灌浆期间营养器官氮素向籽粒发生转移的同时,常常伴随着叶片光合性能的下降和叶片的衰老。不同基因型品种在灌浆期的氮素转移程度不同,表现为随品种演替,旗叶、茎秆和叶鞘中氮素的输出率增加,而转移氮对籽粒氮的贡献率却下降。氮收获指数(NHI)可以描述植物向籽粒分配氮的能力,是衡量作物对氮利用效率的指标。氮收获指数存在显著的基因型差异,虽然现代小麦品种吸氮量高于古老品种,但氮收获指数在现代和古老小麦品种间的差异因不同研究者而异,有的认为现代品种高于古老品种,但也有人认为与年代无关;小麦氮收获指数一般在0.55～0.80之间,很少超过0.8。过去对小麦籽粒灌浆期间的氮素转移虽然进行了大量研究工作,取得了许多重要进展,但仍有许多问题需要进一步深入研究,如根冠关系和灌浆过程中氮素转移的相互关系,田间个体和群体调控及不同高产栽培模式下灌浆过程中氮素转移的     

Effect of Nitrogen Topdressing at Anthesis and the Association of Flag-Leaf Nitrogen with Grain Protein Concentration in Irrigated Spring Wheat

ABSTRACT

Grain protein is an important component affecting the market value of hard red spring wheat (Triticum aestivum). In high-yielding irrigated environments, consistently attaining desired protein levels is a chronic problem. Nitrogen (N) management has a strong effect on protein concentration. The objective of this experiment was to evaluate the robustness of using flag-leaf N concentration as a tool for guiding in-season N application in order to obtain high-protein wheat. Three on-farm trials were conducted (each location using a cultivar of the farmer's choice) where N rates were varied. Nitrogen rates evaluated were 0, 79, 157, 236, and 314 kg ha^?1. To evaluate the benefit of topdressing, all N was applied basally, or 45 kg ha^?1 N was reserved from the basal dose for application at heading. Yield and protein response to applied N were variable across the three sites. This study postulated that this response was a function of initial soil-N availability. Where there was a yield response to N, it appeared that reserving a portion of N for topdressing increased protein but tended to decrease yield. At levels of N where yield was not limited, reserving a portion of N for topdressing did not appear to affect yield or protein. Although a linear relationship between grain protein and flag-leaf N was obtained by pooling data across sites, there was enough variation in this relationship to limit its utility as a tool for guiding in-season N application.     

集雨补灌春小麦花后干物质积累分配及灌浆特性

研究了集雨补灌条件下陇中半干旱区春小麦产量水分效应、开花后干物质积累分配及籽粒灌浆特性。结果表明,集雨补灌对旱地作物具有补偿或超补偿效应,具有明显的增产效应,可提高产量水平、水分利用效率(WUE)及灌水利用效率(IWUE)。孕穗期补灌的WUE最高,而拔节期 孕穗期分期补灌的IWUE最高。经模拟,春小麦的叶、茎、鞘干物质积累动态不同于穗及全株。补灌小麦的干物质积累量、日生产量及相对生长率(RGR)均高于对照。在干物质运转分配方面,补灌小麦较之于对照表现为移动量大,转换率高。补灌延长了春小麦灌浆持续期及提高了平均灌浆速率。     

Nitrogen Availability Affects the Yield of Winter Wheat Subjected to Water Stress during Grain Filling

The effects of irrigation regimes (full irrigation and water-withholding at anthesis) and postanthesis nitrogen (N) supplies (LN, 0; MN 20; and HN, 40 kg N ha^?1) on grain yield and its components in winter wheat were studied, with attention to biomass gain by assimilation and its loss by respiration. Fully irrigated wheat responded to N fertilization with increased grain number (GN) and decreased grain weight (GW), whereas drought-stressed wheat responded with greater GN without significant changes in GW. Apparent whole-plant respiration (R_A) was not influenced by increased postanthesis N fertilizer. Thus, in drought-stressed wheat, the total biomass and stem reserves at maturity were increased by increasing N supply. These results suggest that high N supply at anthesis satisfied the grains’ increased demand for N by increasing postfloral assimilation, and the surplus assimilates not only compensated for the low-N-induced biomass loss by respiration but also may have increased the stem reserves.     

Nitrogen Uptake and Allocation in Sweet Viburnum During a Root Growth Flush

Most woody ornamentals exhibit episodic growth flushes and nitrogen (N) uptake has also been demonstrated to be seasonal. However, there is little information on N uptake in relationship to plant growth cycle. In this study, N uptake and allocation of sweet viburnum during periods of low and high root elongation rates were studied. Plants were fertilized with ammonium nitrate (¹⁵NH₄ ¹⁵NO₃) and after 6 d N absorption was determined. Significantly more N was absorbed by plants with low root elongation rate compared with plants with high root elongation rate. About 70% of the N absorbed by plants with low root elongation rate was allocated to the mature leaves compared to 35% on plants with high root elongation rate. It was evident that root growth activity influenced N absorption and allocation. Although only a small amount of the N absorbed by plants with low root elongation rates was allocated to the immature leaves, significantly more N was allocated to the immature leaves by plants with high root elongation rates. It is possible that the N necessary to support immature leaf growth, when root elongation rate is low, is provided by mobilization from other parts, possibly mature leaves.     

施氮水平对强筋小麦氮素同化及籽粒蛋白质组分积累的影响

在高产条件下研究了施氮水平对强筋小麦济麦20氮素同化及籽粒蛋白质组分积累和品质的影响,结果表明,在0~195 kg/hm2施氮量范围内,增施氮肥显著提高旗叶硝酸还原酶和谷氨酰胺合成酶活性,提高各器官氮素含量和积累量,促进籽粒单体蛋白、可溶性和不溶性谷蛋白积累,提高籽粒蛋白质含量及可溶性和不溶性谷蛋白占总蛋白的比例,改善籽粒品质;285 kg/hm2施氮量处理与195 kg/hm2施氮量处理相比,旗叶硝酸还原酶和谷氨酰胺合成酶活性及籽粒蛋白质含量均无显著变化,但单体蛋白含量及占总蛋白质的比例升高,可溶性和不溶性谷蛋白含量及占总蛋白质的比例降低,籽粒品质下降,兼顾高产和优质的适宜施氮量为105~195 kg/hm2。     

氮肥运筹对稻茬小麦土壤硝态氮含量、根系生长及氮素利用的影响

以宁麦9号为材料,研究施氮量及氮肥基追比例对稻茬小麦土壤硝态氮含量、根系生长、植株氮素积累量、产量和氮素利用效率的影响。结果表明,拔节前0-60cm土层硝态氮含量随基施氮量的增加而显著增加,随生育进程的推进各处理硝态氮显著向下层土壤淋洗;拔节期追施氮肥显著提高了孕穗期0-40cm土层硝态氮含量,且随追施氮量的增加而显著增加,N300和N3/7处理硝态氮显著向40-60cm土层淋洗。根系主要生长于0-20cm土层,拔节前各土层根长密度均随基施氮量的增加而增加,拔节后则随施氮量增加和适当的追肥比例而增加。各施氮处理均以拔节至开花期为小麦氮素积累高峰期。适宜增加施氮量并适当提高追肥比例,有利于提高产量、植株氮素积累量和氮素利用效率。因此,在小麦生产中,适当降低施氮量并提高拔节期追肥比例有利于促进小麦根系生长和植株氮素积累,进而提高小麦产量并减少硝态氮淋洗损失。     

施氮量对稻茬弱筋小麦籽粒氮代谢及灌浆的影响

为探讨施氮量对稻茬弱筋小麦籽粒氮代谢相关酶活性和籽粒蛋白质合成的影响,在大田试验条件下,设置0、75、150、225、300 kg·hm^-2 5个施氮水平,研究不同施氮处理对小麦籽粒氮代谢关键酶活性、籽粒可溶性蛋白、游离氨基酸含量及灌浆特性的影响。结果表明,在0～300 kg·hm^-2施氮范围内,随着施氮量的增加,小麦灌浆期硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷丙转氨酶(GPT)、谷草转氨酶(GOT)活性呈上升趋势,与不施氮处理相比,施氮处理下灌浆期试验点一和试验点二小麦籽粒NR活性提升了0.48%～28.26%和9.49%～23.02%、GS活性提升了7.65%～46.46%和15.97%～57.32%、GPT活性提升了18.79%～74.20%和10.31%～65.13%、GOT活性提升了-5.58%～55.23%和29.76%～66.59%。小麦灌浆期籽粒游离氨基酸、可溶性蛋白、籽粒蛋白质含量和各蛋白质组分含量均随施氮量的增加而增加,当施氮量高于225 kg·hm^-2时,小麦籽粒蛋白质含量超过国家弱筋小麦蛋...     

Agronomic Assessment of Nitrogen Use Efficiency in Spring Wheat and Interrelations with Leaf Greenness Under Field Conditions

Four spring wheat genotypes (Triticum aestivum L.) were grown without (N0 = 0 kg N ha^?1) and under ample (N1 = 250 kg ha^?1) nitrogen (N) fertilizer in field experiments in two seasons. The aim was to assess genotypic variation in N use efficiency (NUE) components and N-related indices during grain filling thus to identify superior wheat genotypes. Leaf chlorophyll (SPAD) readings at crucial growth stages were employed to help differentiate genotypes. Interrelations between yield and N-related indices with SPAD, where also assessed to explain possible pathways of improving NUE early in the growing season. Results showed that genotypic effects on NUE were mostly evident in 2000, a year with drier preanthesis and wetter postanthesis than the normal periods. ‘Toronit’ almost always had the highest biomass yield (BY) and grain yield (GY). Except in 1999 under N0, ‘L94491? showed the highest % grain N concentration (GNC). Genotypes affected SPAD at almost all stages and N fertilization delayed leaf senescence for all genotypes and growth seasons. Correlations between SPAD at different growth stages and GY, N biomass yield at maturity (NBYM) and GNC were significant (P≤ 0.001), positive and strong/very strong (>r = 0.7). N translocation efficiency (NTE) was inversely related to PANU (~r = ? 0.77, P≤ 0.001), suggesting that N after anthesis is being preferentially transported to the ears to meet the N demand of the growing grains. It is concluded that there is still a large potential for increased NUE by improved N recirculation, use of fast and inexpensive crop N monitoring tools and high yielding, N uptake efficient genotypes.

Abbreviations: NUE, Nitrogen use efficiency; SPAD, Minolta SPAD-502 chlorophyll meter, NHI, nitrogen harvest index; HI, Harvest index; NTE, N translocation efficiency from vegetative plant parts to grain; DMTE, dry matter translocation efficiency; CPAY, contribution of pre-anthesis assimilates to yield; PANU, Post-anthesis N uptake, d.a.s., days after sowing, N0, zero (0) kg ha^?1 applied N fertilizer, N1, 250 kg ha^?1 applied N fertilizer.     

Timing and Method of 15Nitrogen-Labeled Fertilizer Application on Grain Protein and Nitrogen Use Efficiency of Spring Wheat

ABSTRACT

Grain protein content is one of the most important quality constraints for bread wheat (Triticum aestivum L.) production in eastern Canada. A field experiment was conducted for two years (1999 and 2000) on the Central Experimental Farm, Ottawa, Canada, to study whether split application of nitrogen (N) fertilizer improved grain protein content and nitrogen-use efficiency (NUE). Two cultivars (‘Celtic,’ as N-responsive and ‘Grandin’, as N-non-responsive) were grown using three different N doses and application methods: (1) 100 kg N ha^?1 as NH₄NO₃, soil-applied at seeding with ¹⁵N₂-labeled NH₄NO₃ to microplots, (2) 60 kg N ha^?1 soil-applied at seeding plus 40 kg N ha^?1 foliar-applied at the boot stage with ¹⁵N₂-labeled urea to microplots, and (3) 90 kg N ha^?1 as soil-applied at seeding plus 10 kg N ha^?1 foliar-applied at the boot stage with ¹⁵N₂-labeled urea to microplots. Plants were sampled at heading and maturity. While dry-matter production and grain yields were not affected by the treatments in either year, N application methods influenced tissue N concentration and NUE. In 1999, extended drought stress led to significant yield reduction; in 2000, foliar application of 10 kg N ha^?1 at the boot stage significantly increased grain N concentration when grain protein was under the limit for bread quality, suggesting that later-applied N can contribute to grain protein content. At maturity, the average NUE was 22.3% in 1999 and 34.5% in 2000, but was always greater when all N was applied at seeding (42.5%) than when N was foliar-applied at the boot stage (18.5% to 24.5%). We conclude that application of a small amount of fertilizer N at the boot stage can improve the bread-making quality of spring wheat by increasing grain protein concentration.     

滴灌量对冬小麦籽粒灌浆特性的影响研究

为优化滴灌冬小麦灌溉制度,于2012—2013年、2013—2014年连续两年在伊宁县采用单因子随机区组试验设计,并运用Logistic方程模拟,研究3 000（处理A）,3 750（处理B）,4 500（处理C）m³/hm²三个滴灌量对冬小麦灌浆特性的影响。结果表明:两年试验冬小麦不同处理平均千粒重分别为48.35,50.27,52.17 g,不同年份不同处理灌浆各阶段持续时间均为缓增期（T₃） > 速增期（T₂） > 渐增期（T₁）,其平均速率分别为1.25,1.92,0.54 mg/d,各阶段平均干物质累积贡献率分别为12.68%,60.90%,26.43%。随着滴灌量的增加,灌浆持续时间延长3～7 d不等,平均灌浆速率减小2.88%～16.79%。3个处理中,处理B具有较高的平均灌浆速率1.21 mg/d,较处理A仅降低了3.41%,较处理C增加了12.25%,适当延长了灌浆时间,但又不致贪青晚熟,较处理C节水750 m³/hm²,可作为大田生产参考。将灌浆参数与粒重进行相关分析得出,多数参数间存在显著或极显著相关关系,其中,平均灌浆速率、最大灌浆速率、灌浆持续期,尤其是速增期与缓增期的持续时间以及它们期间的灌浆速率都与粒重存在着显著或极显著相关性。     

不同施肥措施对冬小麦灌浆期氮素吸收分配的影响

以黄淮海平原国家潮土土壤肥力与肥料效益长期监测站为平台,研究了长期不施肥(CK)、氮钾配施(NK)、氮磷钾配施(NPK)、氮磷钾配施有机肥(MNPK)或秸秆(SNPK)5种施肥措施对灌浆期冬小麦吸收利用氮素的影响.研究结果表明,在等氮量条件下,施氮量为N 165 kg/hm2时,NPK、MNPK、SNPK处理有利于小麦在灌浆阶段维持田间较高的群体数和干物质的积累量;其中MNPK、SNPK处理较NPK处理有利于小麦灌浆阶段在茎、鞘器官的生长和干物质积累.在氮素吸收方面,NPK、MNPK、SNPK处理有利小麦灌浆期茎、叶、鞘、穗等器官对氮素的吸收、分配和累积.与CK处理相比,施无机氮、有机氮分别为N 49.5、115.5 kg/hm2时,MNPK、SNPK处理可以延长灌浆高峰期7天左右;而施无机氮为165 kg/hm2时,与CK处理相比,NPK、NK处理可以延长14天左右.在花后1 ～ 14天,MNPK、SNPK处理在茎、穗部位氮素吸收累积量要高于NPK处理,其中穗部差异分别达到P≤0.05显著水平、P≤0.01极显著水平;在花后21 ～ 35天,NPK处理在叶、籽粒部位氮素吸收累积量要高于MNPK、SNPK处理,其中叶部差异均达到P≤0.05显著水平或P≤0.01极显著水平.此外,在灌浆期MNPK处理在穗部氮素累积量要高于SNPK处理.总之,在本试验条件下,无机有机肥配施应适当加大无机氮肥的供应量以弥补小麦灌浆中后期起氮肥供应不足的现象.     

Utilization of Existing Technology to Evaluate Spring Wheat Growth and Nitrogen Nutrition in South Dakota

Abstract

Sensor‐based technologies for in‐season application of nitrogen (N) to winter wheat (Triticum aestivum L.) have been developed and are in use in the southern Great Plains. Questions arise about the suitability of this technology for spring wheat production in the northern Great Plains. A field experiment was established in Brookings, SD, to evaluate the GreenSeeker Hand Held optical sensor (NTech Industries, Ukiah, CA) for predicting in‐season N status on three spring wheat cultivars (Ingot, Oxen, and Walworth) across five N treatments. Nitrogen rates were 0, 34, 68, 102, and 136 kg N ha^?1 applied preplant as ammonium nitrate. Sensor readings and plant biomass samples were collected at Feekes 6 and Feekes 10 growth stages. The sensor measures reflectance in the red and near infrared (NIR) regions of the electromagnetic spectrum. A normalized difference vegetation index (NDVI) was calculated. The ability of the sensor readings to predict biomass, plant N concentration, and plant N uptake for each sampling date was determined. In general, biomass, plant N concentration, and N uptake increased with increasing N rate for both sampling dates. Readings collected at Feekes 6 and Feekes 10 showed a significant relationship with plant biomass, N concentration, and N uptake for all varieties. Plant N uptake and NDVI resulted in a higher regression coefficients compared to biomass and plant N concentration for all varieties. Results suggest that existing sensor‐based variable nitrogen technology developed for winter wheat could be utilized in the northern Great Plains for estimating in‐season N need for spring wheat.     

水氮互作对冬小麦氮素吸收分配及土壤硝态氮积累的影响

试验采用完全随机裂区设计,研究不同灌水和施氮处理对田间冬小麦氮素吸收转运分配以及成熟期土壤剖面硝态氮分布积累的影响.结果表明:冬小麦氮素吸收速率在拔节-开花期达到最大;阶段氮素吸收量、籽粒氮素积累量和氮收获指数均随灌水量的增加而增加,表现为W1500＞W1200＞W900＞W0;施氮量超过150 kg/hm2时,籽粒氮素积累量、氮收获指数,拔节-成熟期的氮素吸收量不再显著增加;灌水和施氮均能增加冬小麦营养器官氮素转移量,氮素转运率随施氮量增加而增加,氮素转运贡献率随灌水量的增加而降低;冬小麦成熟期表层(0-20 cm)土壤硝态氮含量随着灌水量增加而降低,表现为W0＞W900＞W1200＞W1500;相同灌水处理下,各土层硝态氮含量随施氮量的增加而增加,施氮处理能显著增加0-120 cm土层硝态氮含量,当施氮量超过150 kg/hm2时,随灌水量增加,土壤剖面中的硝态氮由上层向下层移动.     

追氮量对黑小麦品种(系)籽粒产量和品质的影响

为探究追氮量对不同黑小麦品种(系)籽粒产量和品质的影响,本研究采用大田裂区试验设计,主区为11个黑小麦品种(系),副区为追施氮量0(N0,对照)、34.5(N1)、51.8(N2)、69.0(N3)kg·hm²,于小麦灌浆期测定旗叶叶绿素含量(SPAD值),成熟期测定籽粒产量及产量构成要素、籽粒氮素含量和品质指标。结果表明,旗叶SPAD值在追氮处理下均增加,除B145-2、L10056、L10058的旗叶SPAD值在N1最高,其余8个品种(系)的旗叶SPAD值均随追氮量增加而升高。追施氮肥均有利于增加黑小麦产量,与N0相比,N1、N2和N3的产量增幅分别为15.2%~99.7%、17.5%~80.9%和0.7%~69.9%。11个品种(系)获得最高产量的适宜追氮量因品种而异,其中L10056、B120-2、运黑14207籽粒产量随追氮量增加而增加,B145-2、L10058籽粒产量在N2最高,其余6个品种(系)籽粒产量在N1最高。追氮量、品种及二者交互均对产量及构成因素存在极显著影响。追施氮肥能够提高多数黑小麦品种籽粒氮素含量,其中B145-2、L10058和运黑14207在N2最高,18鉴46、临黑131、冬黑1号、临黑187、2002-4、运黑161在N1最高。追氮量与籽粒产量、氮含量、蛋白含量呈正相关(相关性不显著),而产量与籽粒蛋白含量及多数品质指标存在极显著负相关关系。综合考虑黑小麦产量及品质的提高,追氮量在34.5~51.8 kg·hm²之间较为适宜。本研究结果可为黑小麦合理施用氮肥提供参考。     

追氮量对黑小麦品种(系)籽粒产量和品质的影响

为探究追氮量对不同黑小麦品种(系)籽粒产量和品质的影响,本研究采用大田裂区试验设计,主区为11个黑小麦品种(系),副区为追施氮量0(N0,对照)、34.5(N1)、51.8(N2)、69.0(N3)kg·hm²,于小麦灌浆期测定旗叶叶绿素含量(SPAD值),成熟期测定籽粒产量及产量构成要素、籽粒氮素含量和品质指标。结果表明,旗叶SPAD值在追氮处理下均增加,除B145-2、L10056、L10058的旗叶SPAD值在N1最高,其余8个品种(系)的旗叶SPAD值均随追氮量增加而升高。追施氮肥均有利于增加黑小麦产量,与N0相比,N1、N2和N3的产量增幅分别为15.2%~99.7%、17.5%~80.9%和0.7%~69.9%。11个品种(系)获得最高产量的适宜追氮量因品种而异,其中L10056、B120-2、运黑14207籽粒产量随追氮量增加而增加,B145-2、L10058籽粒产量在N2最高,其余6个品种(系)籽粒产量在N1最高。追氮量、品种及二者交互均对产量及构成因素存在极显著影响。追施氮肥能够提高多数黑小麦品种籽粒氮素含量,其中B145-2、L10058和运黑14207在N2最高,18鉴46、临黑131、冬黑1号、临黑187、2002-4、运黑161在N1最高。追氮量与籽粒产量、氮含量、蛋白含量呈正相关(相关性不显著),而产量与籽粒蛋白含量及多数品质指标存在极显著负相关关系。综合考虑黑小麦产量及品质的提高,追氮量在34.5~51.8 kg·hm²之间较为适宜。本研究结果可为黑小麦合理施用氮肥提供参考。     

黄淮南部平原喷灌冬小麦灌浆特性及水氮优化耦合研究

为了优化冬小麦水氮配置,实现养分水分资源高效利用,试验设计3个灌水水平(低灌水W1:25 mm;中灌水W2:40 mm;高灌水W3:55 mm)和5个氮肥水平(N0:0;N1:80 kg/hm^2;N2:180 kg/hm^2;N3:240 kg/hm^2;N4:300 kg/hm^2),共计15个处理,探究了喷灌条件下灌水、施氮及其互作对籽粒灌浆特性及水氮利用效率的影响,并通过建模求解最优水氮配置。结果表明:施氮对te(灌浆持续时间)和tm(最大灌浆速率出现时间)影响显著,两者均随施氮量的增加表现为先增加后降低。N3施氮水平下te和tm最大,均值分别为43.9,24.6天,比N0(不施氮)分别增加1.7,3.0天。W2N3处理的tm值最大,比最小处理W1N0延后5.0天。GFmax(最大灌浆速率)与AG(平均灌浆速率)呈极显著相关(r=0.841**),千粒重与产量(r=0.791**)、te(r=0.755**)和tm(r=0.717**)呈极显著正相关。W2N3组合产量和WUE(水分利用效率)均为最大,分别为8960 kg/hm^2和2.83 kg/m^3。水氮耦合通过优化灌浆过程可有效提高冬小麦产量。喷灌灌水定额26~35 mm、施氮量193~204 kg/hm^2(基施40%+拔节期追施60%)的水氮资源配置模式可实现节水增产双效目标。     

大气CO2浓度升高对不同穗型冬小麦灌浆动态的影响

利用开放式空气中CO2浓度升高系统（Free Air CO2 Enrichment,FACE),以CO2浓度为主处理,FACE圈内白天（5：30-18：00）CO2浓度550±17μL·L-1,对照浓度400±16μL·L-1,品种为副处理,选取大穗型（陕旱8675）、中穗型（京冬8号）和多穗型（胜利麦）3个小麦品种为研究对象进行实验,研究未来CO2浓度升高条件下,不同穗型冬小麦品种籽粒灌浆特征的动态变化。结果表明：（1）CO2浓度升高明显增加了各品种的初始粒重。中穗型品种京冬8号灌浆前期粒重增加,但最终籽粒重无影响,其灌浆时间和平均灌浆速率影响亦不明显;大穗型品种陕旱8675灌浆时间比对照延长19.3%,其籽粒重显著增加,穗上、中、下部增重分别为11.0%、20.9%、23.3%,全穗增重18.8%;CO2浓度升高后多穗型品种胜利麦灌浆速率的降低抵消了灌浆时间延长对籽粒总重的效应,其灌浆过程粒重增加不明显。（2）CO2浓度升高对多穗型品种京冬8号和大穗型品种陕旱8675灌浆参数（最大灌浆速率、到达最大灌浆速率的时间、平均灌浆速率和灌浆时间）的影响均表现为上部和下部穗大于中部穗,而多穗型品种胜利麦中部穗各灌浆参数变化幅度明显高于上、下部穗。（3）CO2浓度升高条件下,京冬8号和陕旱8675均表现为前期灌浆时间缩短,中、后期灌浆时间延长,而其在3个时期的平均灌浆速率变化正好相反;胜利麦在3个时期的灌浆时间均延长,平均灌浆速率降低。研究表明大穗型冬小麦品种比多穗型品种对大气CO2浓度增加的响应更明显。     

籽粒灌浆过程气候因子对不同品质类型春小麦产量和蛋白质含量的影响之二:水分的影响

对3个不同品质和产量类型的春小麦品种在籽粒灌浆过程进行水分处理。结果表明，高产品种东农7742和新克旱9号产量均随水分增多而增加，水分较少时增加明显，水分较多时变化趋缓；低产品种Roblin的产量在灌水量为80mm水平时达最大，此后随水分增多而下降。东农7742和新克旱9号蛋白质含量随水分增多呈下降趋势，而Roblin的变化较小。     

不同氮效率小麦品种根系特征及根际土壤酶活性的分析

为探明不同氮效率小麦（Triticum aestivum L.）品种根系特征及其对根际土壤酶活性的响应,以30年的长期定位试验为平台,于2018—2020年采用大田试验的方法,在不同氮效率品种筛选的基础上,以氮高效小麦品种郑麦113、偃高21和氮低效小麦品种丰德存5号、周麦27为试验材料,在不施氮肥（N0）和正常施氮肥（N1）条件下研究其根系特征、氮素吸收利用及根际土壤酶活性的差异。结果表明,各品种小麦的根系活力均在孕穗期达到最大值,N0、N1水平下氮高效小麦品种根系活力的平均值分别比氮低效小麦品种增加了16.13%～24.22%、10.22%～62.49%。N1水平下小麦根长、根表面积和根体积明显高于N0水平。郑麦113、偃高21、周麦27的氮吸收效率显著高于丰德存5号,而周麦27的氮利用效率较低。两种氮水平处理下,郑麦113和偃高21的根际土壤β-葡萄糖苷酶（BG）、亮氨酸氨基肽酶（LAP）和多酚氧化酶（POX）活性整体显著高于丰德存5号和周麦27(P<0.05),且根际土壤酶活性与根系形态指标均呈正相关关系。这说明郑麦113和偃高21较高的根系活力、根长、根表面积和根体积促...