Effects of zinc fertilizer and short-term high temperature stress on wheat grain production and wheat flour proteins

Content of wheat flour proteins affects the quality of wheat flour.Zinc nutrition in wheat can change the protein content of the flour.The inconsistency and instability of wheat grain quality during grain filling while under high temperature stress(HTS)are major problems in the production of high quality wheat.At present,there is a lack of studies on zinc fertilizer and HTS effects on wheat flour protein and the content of its components.For this study,treatment combinations of four levels of zinc fertilizers and exposure to a short-term HTS,at 20 d after flowering(D20),were tested on two wheat cultivars with different gluten levels.Individuals of a strong gluten wheat,Gaoyou 2018(GY2018),and a medium gluten wheat,Zhongmai 8(ZM8),were grown in pots at the Institute of Crop Sciences,Chinese Academy of Agricultural Sciences,Beijing in 2015–2017.We measured grain yield and weight and the activities of two enzymes(nitrate reductase and glutamine synthetase)from the flag leaves,collected at D10 and D20.Total protein content,protein yield,and content of four protein components(albumin,gliadin,glutenin,and globulin)were measured from flour produced from the pot-grown plants.HTS significantly increased the contents of total protein,albumin,gliadin,and glutenin in wheat grains,and reduced the grain yield,grain weight,protein yield,globulin content,and flag leaf nitrate reductase(NR)and glutamine synthetase(GS)activities.The results showed that HTS and zinc fertilizer had greater impacts on the strong gluten cultivar compared to the medium gluten cultivar.Under HTS,grain yield decreased by 13 and 8% in GY2018 and ZM8,respectively;protein yield decreased by 7 and 8% in GY2018 and ZM8,respectively.Zinc fertilizer increased:grain and protein yields;grain weight;total protein,albumin,gliadin,and glutenin contents;protein yield;and NR and GS activities.In contrast,zinc fertilizer reduced the content of globulin.The addition of 15 mg Znsoil had the strongest effect on grain yield and quality as compared to the other three treatments(additions of 0,30,and 45 mg Znsoil).Zinc fertilizer also reduced the negative effects of HTS on protein yield,content,and components’content.Therefore,wheat grown with additional zinc in the soil can improve the quality of the flour.     

冬小麦谷粒产量,谷粒蛋白产量,谷粒蛋白含量和稳定性分析

基因型与环境的互作对基因型筛选具有重要作用,并且使品种筛选变得复杂.本文对法国27个冬小麦品种在27个生长环境中获得的试验数据进行了分析比较,同时对高谷粒产量(GY),谷粒蛋白产量(GPY),谷粒蛋白含量(GPC)和稳定性的几种方法进行了筛选:Kang秩和方法(指标1:相同权重的3种谷粒性状和Shukla稳定性方差δ2)以及5种衍生的秩和指标(指标2～6:3种谷粒性状高于δ2 2～6倍的权重),稳定性方差(s2)和回归系数(b),研究它们之间的秩相关性以及它们与3种谷粒性状的相关性.结果表明:3种稳定性统计δ2,s2和b对同时筛选3种谷粒性状指标和稳定性都是非常有用的方法.对于GPY的筛选,指标1秩和方法比稳定性方差s2略保守.指标2比指标1和稳定方差s2更好地筛选到高GY和高GPY.指标3,指标4,指标5和指标6更适合于初始筛选3种谷粒性状.所有的稳定性统计方法都能很好与3种谷粒性状秩相关.稳定性方差s2和回归系数b之间在除了GY之外的3种谷粒性状中秩相关性不高,稳定性方差δ2和稳定性方差s2之间在3种谷粒性状中都具有很强的秩相关性.3种稳定性统计在高产和低产的环境中重复性不高,同样,在2个年份之间的重复性也可以忽略.但是,在随机抽取的4个环境之间的重复性却非常高.     

Grain yield and grain moisture associations with leaf,stem and root characteristics in maize

Improving grain yield(GY) and reducing grain moisture(GM) are urgent demands for directly harvesting kernels with combine harvesters in maize production. GY and GM are both related to leaf, stem and root characteristics, but the relationships are not fully understood. To better understand these relationships, we conducted a field trial involving 12 maize hybrids with two sowing dates in 2017 and 10 maize hybrids with one sowing date in 2019. GY ranged from 6.5–14.6 t ha^–1 in early-sow...     

小麦干物质、果聚糖和氮的积累分配及其与籽粒产量和品质的关系

在200kg/hm2施N条件下,对17个澳大利亚小麦品种的干物质、果聚糖、氮的积累分配及其与籽粒产量(GY)、籽粒氮产量(GNY)及籽粒氮含量(GNC)的关系进行了研究。结果表明,干物质、果聚糖和氮积累的模式相似,在叶片、茎秆和植株中分别于开花期、乳熟期和成熟期积累到最大值。在开花前,茎秆是贮存果聚糖的主要器官,叶片是氮的主要贮存器官,而在花期后,籽粒成为贮存果聚糖和氮最多的器官,其次为茎秆。从乳熟期至成熟期,随着干物质、果聚糖和氮在营养器官中积累的降低,GY、GNY和籽粒果聚糖积累快速增加。在多数取样期,植株干物质积累和果聚糖积累与GY和GNY呈极显著正相关,与GNC呈负相关;成熟期植株氮积累与GY呈显著负相关,与GNC显著正相关;在花期后,叶片和茎秆氮积累与GY和GNY呈显著负相关。     

施氮、锌对镉污染小麦产量及籽粒锌、镉含量的影响

为了明确氮、锌、镉处理及其互作对小麦产量和籽粒锌、镉含量的影响,本研究设置盆栽裂区试验,以扬麦25为供试材料,主区氮处理设常氮(1.6 g·盆^-1)和减氮(0.8 g·盆^-1),裂区锌、镉处理设对照、锌处理(150 mg·kg^-1)、镉处理(5 mg·kg^-1)和锌+镉处理,测定小麦产量性状,籽粒不同组分(面粉、次粉和麸皮)氮、锌、镉含量以及籽粒锌、镉有效富集系数。结果表明：与常氮相比,减氮处理使小麦籽粒产量显著降低,这主要与产量构成因子、生物产量和收获指数均显著下降有关;减氮条件下小麦成熟籽粒氮含量(不同组分10%～15%)、镉含量(12%～16%)以及镉有效富集系数亦显著降低。与不施锌相比,土壤施锌对籽粒产量和氮含量均无显著影响,但使籽粒锌含量大幅增加(14%～30%),使镉含量(18%～28%)以及锌、镉有效富集系数均显著下降。土壤镉处理对籽粒产量和氮含量均无显著影响,使籽粒镉含量(38～42倍)以及锌、镉有效富集系数均显著增加,而使锌含量显著下降(3%～12%)。籽粒组分及其与镉、锌处理的互...     

啤酒大麦产量与籽粒品质的综合栽培效应

研究了5个栽培技术因素对啤酒大麦产量、粒重和蛋白质含量3个主要生产指标性状的综合效应。结果表明：适期早播（10月13日-11月2日）、增加基本苗密度（6-22万/亩）、等量氮肥早施对籽粒产量有正效应,而对粒重和蛋白质含量有负效应;施氮量（20kg/亩以下）增加,产量和蛋白质含量都提高,粒重表现二次反应;基追氮肥比例的作用较不明显,仅有微弱的效应。不同条件下,产量与粒重均负相关;产量、粒重与蛋白质含量之间的相关因所考虑的因子而定。各个因子的综合效应大小依次为：施氮量＞播期＞施氮时期＞基本苗密度＞基追氮肥比例。     

不同基因型高粱的氮效率及对低氮胁迫的生理响应

【目的】探讨不同基因型高粱氮素吸收效率和利用效率及其差异机制,研究低氮胁迫对不同基因型高粱叶片无机氮含量和氮同化酶活性的影响,为耐低氮型高粱品种的选育提供理论依据。【方法】采用盆栽试验,选取2个低氮敏感型高粱(冀蚜2号和TX7000B)和2个耐低氮型高粱(SX44B和TX378)为试验材料,设置高氮(0.24g·kg-1风干土)和低氮(0.04 g·kg-1风干土)2个处理,分别在挑旗期和灌浆期测定高粱叶片NO3--N、NO2--N及NH4+-N含量和硝酸还原酶(NR)、亚硝酸还原酶(Ni R)、谷氨酰胺合成酶(GS)和谷氨酸合成酶(GOGAT)活性,分析不同基因型高粱在2个氮处理下的氮效率相关指标及其差异。【结果】(1)不同基因型高粱籽粒产量对低氮的响应不同,低氮处理显著降低了冀蚜2号和TX7000B的籽粒产量,与高氮处理比较分别降低13.87%和19.25%,但没有降低SX44B和TX378的籽粒产量。(2)与高氮处理比较,低氮处理的相对籽粒氮累积量、相对植株氮累积量和相对氮收获指数不能表征各基因型高粱是否具有耐低氮特性;但相对低氮敏感型高粱,耐低氮型高粱在低氮处理下有着较高的相对氮肥偏生产力和相对氮素利用效率。低氮处理下SX44B和TX378的氮肥偏生产力是高氮处理的6.19和7.49倍,而冀蚜2号和TX7000B则分别为5.17和4.85倍;低氮处理下SX44B和TX378的氮素利用效率是高氮处理的1.84和1.85倍,而冀蚜2号和TX7000B则分别为1.67和1.35倍。(3)通径分析表明,高氮处理下,植株氮累积量和氮素利用效率对籽粒产量贡献相同;而在低氮处理下,氮素利用效率对籽粒产量关联作用更大。(4)高粱的叶片无机氮含量不能表征高粱是否具有耐低氮特性,灌浆期叶片无机氮含量较挑旗期显著降低。(5)与高氮处理比较,低氮处理时冀蚜2号和TX7000B叶片中NR、GS和GOGAT活性显著降低,SX44B酶活性变化不显著,而TX378叶片中GS活性增加。【结论】耐低氮型高粱在低氮胁迫时有着较高的相对籽粒产量和相对氮素利用效率。低氮胁迫时叶片较高的氮同化酶活性是高粱耐低氮的生理基础。发掘和利用低氮条件下具有较高的叶片氮同化酶活性和氮素利用效率的高粱种质资源,有助于提高耐低氮高粱品种的培育效率。     

Prediction of yield and the contribution of legumes in legume-grass mixtures using field spectrometry

Productivity and botanical composition of legume-grass swards in rotation systems are important factors for successful arable farming in both organic and conventional farming systems. As these attributes vary considerably within a field, a non-destructive method of detection while doing other tasks would facilitate more targeted management of crops and nutrients in the soil–plant–animal system. Two pot experiments were conducted to examine the potential of field spectroscopy to assess total biomass and the proportions of legume, using binary mixtures and pure swards of grass and legumes. The spectral reflectance of swards was measured under artificial light conditions at a sward age ranging from 21 to 70 days. Total biomass was determined by modified partial least squares (MPLS) regression, stepwise multiple linear regression (SMLR) and the vegetation indices (VIs) simple ratio (SR), normalized difference vegetation index (NDVI), enhanced vegetation index (EVI) and red edge position (REP). Modified partial least squares and SMLR gave the largest R ² values ranging from 0.85 to 0.99. Total biomass prediction by VIs resulted in R ² values of 0.87–0.90 for swards with large leaf to stem ratios; the greatest accuracy was for EVI. For more mature and open swards VI-based detection of biomass was not possible. The contribution of legumes to the sward could be determined at a constant biomass level by the VIs, but this was not possible when the level of biomass varied.     

灌浆期高温前喷施叶面喷剂对小麦产量及籽粒品质的影响

为探明不同叶面喷剂对小麦灌浆期高温危害的缓解作用,于安徽农业大学农萃园2019-2020年小麦生长季内选用0.3％ KH2PO4 (PDP)和0.01％芸苔素内酯溶液(BR)开展了大田试验研究.试验设置小麦灌浆期内自然高温来临前连续喷两次PDP、BR及二者的混合溶液(PB),以喷施等量清水为对照(CK),考察喷施后不同处理对小麦旗叶叶绿素含量、干物质积累、产量及产量构成因素和籽粒品质的影响.结果 表明:灌浆期高温前喷施PDP、BR均可提升高温后旗叶叶绿素含量,PDP与BR无显著差异,PB处理叶绿素含量最高;不同叶面喷剂显著增加小麦干物质积累,PB总干物质积累量显著高于BR和PDP,后两者间无显著差异:PB干物质量最高是由于其对茎叶及籽粒干物质的提升最多;和CK相比,PDP、BR和PB产量均显著提高,增产幅度为5.43％～-9.41％,PB处理产量最高.灌浆期高温前喷施PDP、BR和PB显著改善籽粒品质,主要不同程度地提高了籽粒蛋白质和湿面筋含量,延长面团稳定时间、形成时间及提高面粉沉淀值.综上,小麦灌浆期高温前通过叶面喷施PDP、BR和PB均能显著延缓灌浆期叶片衰老,促进干物质积累,协同提升产量与籽粒品质.以0.3％磷酸二氢钾和0.01％芸苔素内酯溶液混合喷施效果最佳.     

Effect of delayed sowing on grain number,grain weight,and protein concentration of wheat grains at specific positions within spikes

Delays in sowing have significant effects on the grain yield, yield components, and grain protein concentrations of winter wheat. However, little is known about how delayed sowing affects these characteristics at different positions in the wheat spikes. In this study, the effects of sowing date were investigated in a winter wheat cultivar, Shannong 30, which was sown in 2019 and 2020 on October 8 (normal sowing) and October 22 (late sowing) under field conditions. Delayed sowing increased the partitioning of ¹³C-assimilates to spikes, particularly to florets at the apical section of a spike and those occupying distal positions on the same spikelet. Consequently, the increase in grain number was the greatest for the apical sections, followed by the basal and central sections. No significant differences were observed between sowing dates in the superior grain number in the basal and central sections, while the number in apical sections was significantly different. The number of inferior grains in each section also increased substantially in response to delayed sowing. The average grain weights in all sections remained unchanged under delayed sowing because there were parallel increases in grain number and ¹³C-assimilate partitioning to grains at specific positions in the spikes. Increases in grain number m^–2 resulted in reduced grain protein concentrations as the limited nitrogen supply was diluted into more grains. Delayed sowing caused the greatest reduction in grain protein concentration in the basal sections, followed by the central and apical sections. No significant differences in the reduction of the grain protein concentration were observed between the inferior and superior grains under delayed sowing. In conclusion, a 2-week delay in sowing improved grain yield through increased grain number per spike, which originated principally from an increased grain number in the apical sections of spikes and in distal positions on the same spikelet. However, grain protein concentrations declined in each section because of the increased grain number and reduced N uptake.     

Effects of Powdery Mildew on 1000-Kernel Weight,Crude Protein Content and Yield of Winter Wheat in Three Consecutive Growing Seasons

In order to clarify the impact posed by wheat powdery mildew (Blumeria graminis f. sp. tritici) on the yield and yield components in different epidemic seasons, field trials were conducted in three growing seasons, 2009–2010, 2010–2011 and 2011–2012, in Langfang City, Hebei Province, China. The relationships between 1000-kernel weight, crude protein content of grain and yield and disease index (DI), as well as area under disease progress curve (AUDPC) were studied. The models of the percentage of loss of 1000-kernel weight, crude protein content and yield were constructed using DI at critical point (CP) of growth stages (GS) and AUDPC in the three growing seasons, respectively. The CPs for estimating 1000-kernel weight, crude protein content of grain and yield of wheat caused by powdery mildew were GS 11.1, GS 10.5.3 and GS 10.5.3, respectively. Models based on DI at CP to estimate the percentage of loss of 1000-kernel weight, crude protein content of grain and yield were better than models based on AUDPC. And models of the percentage of loss of 1000-kernel weight, crude protein content and yield for 2011–2012 season were significant different from these for 2009–2010 and 2010–2011 seasons. These results indicated that besides powdery mildew, weather conditions also had influence on 1000-kernel weight, crude protein content of grain and yield loss of wheat when powdery mildew occurred.     

Active remote sensing and grain yield in irrigated maize

Advances in agricultural technology have led to the development of active remote sensing equipment that can potentially optimize N fertilizer inputs. The objective of this study was to evaluate a hand-held active remote sensing instrument to estimate yield potential in irrigated maize. This study was done over two consecutive years on two irrigated maize fields in eastern Colorado. At the six- to eight-leaf crop growth stage, the GreenSeeker? active remote sensing unit was used to measure red and NIR reflectance of the crop canopy. Soil samples were taken before side-dressing from the plots at the time of sensing to determine nitrate concentration. Normalized difference vegetation index (NDVI) was calculated from the reflectance data and then divided by the number of days from planting to sensing, where growing degrees were greater than zero. An NDVI-ratio was calculated as the ratio of the reflectance of an area of interest to that of an N-rich portion of the field. Regression analysis was used to model grain yield. Grain yields ranged from 5 to 24 Mg ha^?1. The coefficient of determination ranged from 0.10 to 0.76. The data for both fields in year 1 were modeled and cross-validated using data from both fields for year 2. The coefficient of determination of the best fitting model for year 1 was 0.54. The NDVI-ratio had a significant relationship with observed grain yield (r ² = 0.65). This study shows that the GreenSeeker? active sensor has the potential to estimate grain yield in irrigated maize; however, improvements need to be made.     

Spectral reflectance indices as proxies for yield potential and heat stress tolerance in spring wheat: heritability estimates and marker-trait associations

The application of spectral reflectance indices (SRIs) as proxies to screen for yield potential (YP) and heat stress (HS) is emerging in crop breeding programs. Thus, a comparison of SRIs and their associations with grain yield (GY) under YP and HS conditions is important. In this study, we assessed the usefulness of 27 SRIs for indirect selection for agronomic traits by evaluating an elite spring wheat association mapping initiative (WAMI) population comprising 287 elite lines under YP and HS conditions. Genetic and phenotypic analysis identified 11 and 9 SRIs in different developmental stages as efficient indirect selection indices for yield in YP and HS conditions, respectively. We identified enhanced vegetation index (EVI) as the common SRI associated with GY under YP at booting, heading and late heading stages, whereas photochemical reflectance index (PRI) and normalized difference vegetation index (NDVI) were the common SRIs under booting and heading stages in HS. Genome-wide association study (GWAS) using 18704 single nucleotide polymorphisms (SNPs) from Illumina iSelect 90K identified 280 and 43 marker-trait associations for efficient SRIs at different developmental stages under YP and HS, respectively. Common genomic regions for multiple SRIs were identified in 14 regions in 9 chromosomes: 1B (60–62 cM), 3A (15, 85–90, 101– 105 cM), 3B (132–134 cM), 4A (47–51 cM), 4B (71– 75 cM), 5A (43–49, 56–60, 89–93 cM), 5B (124–125 cM), 6A (80–85 cM), and 6B (57–59, 71 cM). Among them, SNPs in chromosome 5A (89–93 cM) and 6A (80–85 cM) were co-located for yield and yield related traits. Overall, this study highlights the utility of SRIs as proxies for GY under YP and HS. High heritability estimates and identification of marker-trait associations indicate that SRIs are useful tools for understanding the genetic basis of agronomic and physiological traits.     

Developing a new Crop Circle active canopy sensor-based precision nitrogen management strategy for winter wheat in North China Plain

Active canopy sensor (ACS)—based precision nitrogen (N) management (PNM) is a promising strategy to improve crop N use efficiency (NUE). The GreenSeeker (GS) sensor with two fixed bands has been applied to improve winter wheat (Triticum aestivum L.) N management in North China Plain (NCP). The Crop Circle (CC) ACS-470 active sensor is user configurable with three wavebands. The objective of this study was to develop a CC ACS-470 sensor-based PNM strategy for winter wheat in NCP and compare it with GS sensor-based N management strategy, soil N_min test-based in-season N management strategy and conventional farmer’s practice. Four site-years of field N rate experiments were conducted from 2009 to 2013 to identify optimum CC vegetation indices for estimating early season winter wheat plant N uptake (PNU) and grain yield in Quzhou Experiment Station of China Agricultural University located in Hebei province of NCP. Another nine on-farm experiments were conducted at three different villages in Quzhou County in 2012/2013 to evaluate the performance of the developed N management strategy. The results indicated that the CC ACS-470 sensor could significantly improve estimation of early season PNU (R² = 0.78) and grain yield (R² = 0.62) of winter wheat over GS sensor (R² = 0.60 and 0.33, respectively). All three in-season N management strategies achieved similar grain yield as compared with farmer’s practice. The three PNM strategies all significantly reduced N application rates and increased N partial factor productivity (PFP) by an average of 61–67 %. It is concluded that the CC sensor can improve estimation of early season winter wheat PNU and grain yield as compared to the GS sensor, but the PNM strategies based on these two sensors perform equally well for improving winter wheat NUE in NCP. More studies are needed to further develop and evaluate these active sensor-based PNM strategies under more diverse on-farm conditions.     

Prediction of protein content in malting barley using proximal and remote sensing

This paper examines the prediction of within-field differences in protein in malting barley at a late growth stage using the Yara N-Sensor and prediction of its regional variation with medium resolution satellite images. Field predictions of protein in the crop at a late growth stage could be useful for harvest planning, whereas regional prediction of barley quality before harvest would be useful for the grain industry. The project was carried out in central Sweden where the variation in protein content of malting barley has been documented both within fields and regionally. Scanning with an N-sensor and crop sampling were carried out in 2007 and 2008 at several fields. The regional data used consisted of weather data, quality analyses of the malting barley delivered to the major farmers’ co-operative, crops grown and field boundaries. Satellite scenes (SPOT 5 and IRS-P6 LISS-III) were acquired from a date as close as possible to the N-sensor scans. Reasonable partial least squares (PLS) models could be constructed based on weather and reflectance data from either the N-sensor or satellite. The models used mainly reflectance data, but the weather data improved them. Better field models could be created with data from the N-sensor than from the satellite image, but a local satellite-based model based on a simple ratio (middle infrared/green) in combination with weather was useful in regional prediction of malting barley protein. A regional prediction model based only on the weather variables explained about half the variation in recorded protein.     

地表臭氧对中国主要粮食作物产量与品质的影响：现状与展望

目前,中国地表臭氧污染水平已位列世界前列,对国内粮食安全造成了严重威胁。针对当前严重的大气污染,并且基于该领域的研究热点,本文综述了地表臭氧在农业生态风险方面的研究现状与展望。主要包括地表臭氧对作物产量和品质的影响与机制及其区域风险评估的方法与结果。提出了未来研究应着重关注臭氧区域风险评估的精准性和全面性,开发作物多品种的臭氧气孔通量模型以及建立科学的评估指标体系。此外,要探求高效减缓臭氧损伤的农艺管理措施,以及加强多因子复合实验的开展与无人机生态遥感监测技术的应用。     

Relationships Between Yield Monitor Data and Airborne Multidate Multispectral Digital Imagery for Grain Sorghum

Remote sensing imagery taken during a growing season not only provides spatial and temporal information about crop growth conditions, but also is indicative of crop yield. The objective of this study was to evaluate the relationships between yield monitor data and airborne multidate multispectral digital imagery and to identify optimal time periods for image acquisition. Color-infrared (CIR) digital images were acquired from three grain sorghum fields on five different dates during the 1998 growing season. Yield data were also collected from these fields using a yield monitor. The images and the yield data were georeferenced to a common coordinate system. Four vegetation indices (two band ratios and two normalized differences) were derived from the green, red, and near-infrared (NIR) band images. The image data for the three bands and the four vegetation indices were aggregated to generate reduced-resolution images with a cell size equivalent to the combine's effective cutting width. Correlation analyses showed that grain yield was significantly related to the digital image data for each of the three bands and the four vegetation indices. Multiple regression analyses were also performed to relate grain yield to the three bands and to the three bands plus the four indices for each of the five dates. Images taken around peak vegetative development produced the best relationships with yield and explained approximately 63, 82, and 85% of yield variability for fields 1, 2, and 3, respectively. Yield maps generated from the image data using the regression equations agreed well with those from the yield monitor data. These results demonstrated that airborne digital imagery can be a very useful tool for determining yield patterns before harvest for precision agriculture.     

Application of Probability Analysis to Assess Nitrogen Supply to Grain Crops in Northern Australia

Grain yield and protein of cereal crops in northern Australia provide a useful indicator of the supply of available nitrogen (N) to the crop. Our intention was to utilize this principle on a site-specific basis through an associated probabilistic framework to identify the likelihood that grain yield was limited by N supply. Yield and protein data were taken at harvest from sorghum, wheat and barley crops near Dalby, southern Queensland, in 1999. Considerable variation was found in grain yield for the three crops, but less so for grain protein. Frequency–response relationships, derived from historical multiple N field experiments, were applied to identify areas where grain yield was limited by N supply. This approach indicated that there was a 60% or higher likelihood that plant-available N was yield-limiting for 17%, 23%, and 26% of the area sown to sorghum, wheat and barley, respectively. These areas were not necessarily those where crop yield was relatively low. Calculation of N removal and N supply, using N transfer efficiency relationships, verified that those areas with a high likelihood of response to N had considerably lower supplies of N compared to other areas. The application of probability analysis offers a unique strategy to identify within-field areas where N supply could be yield-limiting, and provides a rationale for predicting the spatial variation and likely range of N supplies for successive seasons.     

孕穗期干旱胁迫对寒地粳稻籽粒氮素形成及产量的影响

为探究孕穗期干旱胁迫对寒地粳稻籽粒氮素形成及产量影响,以水稻松粳6(不耐旱型)和东农425(耐旱型)为材料,通过盆栽控水方式于孕穗期不同梯度干旱处理(土壤水势分别为:0、-10、-25、-40 k Pa),20 d后恢复正常管理。结果表明,与对照相比,轻度干旱胁迫下(土壤水势为-10 k Pa)籽粒氮代谢关键酶(GS、GPT、GOT)活性显著升高,东农425增幅高于松粳6;重度干旱胁迫(土壤水势为-40 k Pa)下酶活性显著降低,东农425降幅小于松粳6,品种间差异显著。干旱胁迫可提高籽粒蛋白质及各组分含量,籽粒清蛋白、球蛋白含量升高主要受GS、GPT和GOT活性变化影响,醇蛋白含量升高与籽粒GS活性关系密切,谷蛋白含量变化主要受籽粒GPT、GOT活性影响。孕穗期干旱胁迫显著降低寒地粳稻产量,随土壤水势降低,产量降幅逐渐增大,东农425降幅显著低于松粳6,产量降低主要影响因素是穗粒数、结实率和千粒重。文章从氮代谢关键酶调控角度分析孕穗期干旱胁迫对寒地粳稻籽粒灌浆过程中蛋白质及各组分含量和产量影响,为揭示干旱胁迫下寒地粳稻产量及品质形成机制提供理论依据。     

臭氧浓度升高和叶面施锌对小麦籽粒产量、锌浓度及有效性的影响

研究臭氧浓度升高和叶面施锌对小麦产量和籽粒不同组分锌营养的影响,为气候变化背景下小麦的锌生物强化提供理论依据和技术参考。利用自然光气体熏蒸平台,以富锌小麦品种青紫1号为供试材料,臭氧处理设清洁空气和臭氧浓度升高(100nL·L-1,拔节至收获),锌处理设对照(喷清水)和叶面施锌(开花期及花后1周叶面喷施0.1%Zn2+),成熟期测定小麦产量及其构成因素、籽粒各组分的锌浓度、锌含量、植酸浓度以及植酸与锌的摩尔比。叶面施锌处理对小麦籽粒产量没有影响,但臭氧浓度升高使产量平均下降66%。臭氧胁迫导致的产量损失主要与粒重明显减轻(53%)有关,其次亦与每穗粒数减少(27%)有关,而穗数没有变化。麦粒各组分锌浓度、植酸浓度以及植酸与锌摩尔比均表现为麸皮次粉面粉。与清洁空气相比,臭氧浓度升高使籽粒各组分的锌浓度和植酸浓度均明显增加,分别增加15%～41%和8%～45%,各组分植酸与锌摩尔比无显著变化;臭氧浓度升高使小麦面粉锌累积量占籽粒总锌的百分比显著减少。与对照相比,叶面施锌使小麦各组分锌浓度平均增加22%～24%,使植酸与锌摩尔比平均减少15%～19%,但籽粒各组分植酸浓度以及锌在各组分的分配比例均无显著影响。臭氧与锌处理对所有测定参数均无交互作用,但这两个处理与籽粒组分之间多存在不同程度的互作效应。臭氧胁迫环境下青紫1号籽粒产量和锌累积量大幅下降,籽粒各组分锌浓度显著增加,但生物有效性没有变化;花后叶面施锌对小麦产量没有影响,但使籽粒不同组分锌的营养水平均明显增加,且增幅不受臭氧浓度升高的影响。