Phytopathological characteristics of leaf rust resistance of new winter wheat varieties

The characteristics of types of leaf rust resistance of 14 winter wheat varieties under artificial climate chamber and field conditions as well as recommendations on their effective use are given.     

基于WOFOST作物生长模型的冬小麦干旱影响评估技术

为了反映作物与干旱的相互关系,人为再现干旱灾害对作物产量的影响程度,选择华北地区冬小麦干旱灾害为研究对象,对作物生长模型WOFOST在区域上进行适应性进行分析、检验的基础上,然后利用区域作物模型实现干旱灾害对作物影响定量分析和动态评估.以减产率和气象条件作为灾害严重程度划分的标准,利用数值模拟试验,确定导致减产的主要气象因子及其量值,对研究区干旱灾害进行影响评估,包括典型灾害年份影响评估和年代际灾害影响评估,并给出了评估结果.     

水稻产量形成与叶片含氮量及叶色的关系

以 6个中晚熟水稻品种为材料 ,研究了不同时期叶片含氮量与分蘖发生、穗粒形成及产量的关系。结果表明 ,分蘖发生率随出生时叶片含氮量提高而提高 ,分蘖发生与终止的临界叶片含氮量随分蘖出生期推迟而逐步提高 ;穗颖花数主要受倒 2叶期、倒 1叶期叶片氮状况影响 ,结实率与抽穗期叶片氮状况有关 ,穗颖花数和结实率最高时叶片含氮量粳稻为 2 7～ 2 8g·kg-1,籼稻为 2 5g·kg-1左右。试验发现 ,N -n叶龄期、倒 2叶期和抽穗期主茎顶 4叶叶色接近或略深于顶 3叶为不同品种高产的共同特征 ,并提出了高产水稻适宜的叶片含氮量指标     

水肥条件对冬小麦旗叶光合特性及生物量的影响

【目的】研究水肥耦合对冬小麦旗叶光合特性及生物量的影响,建立旱地冬小麦生产的合理水肥管理模式。【方法】2011-2012年,以长旱58为供试材料,设置水分(W)和肥料(Y)2个因子,其中水分包括不灌水、低灌水量、中灌水量、高灌水量4个水平,肥料包括不施肥、低肥、中肥、高肥4个水平,共16个处理,于小麦不同生育时期测定其光合指标(净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr))及生物量。【结果】1)方差分析表明,水分对小麦旗叶光合特性的影响大于肥料,各施肥水平下,旗叶Pn、Gs、Tr与水分呈正相关。不论在何种水肥组合处理中,随着生育期的延长,冬小麦旗叶Pn、Gs、Tr均呈先升后降趋势,于开花期达到最大值。2)在中等施肥量水平下,小麦开花期低灌水量处理较不灌水处理、中灌水量处理较低灌水量处理Pn分别显著提高3.25%和5.01%,Gs分别显著提高10.20%和5.34%,Tr分别提高7.76%和0.15%。3)在土壤水分较充足时,小麦旗叶Pn、Gs、Tr随施肥水平的增加而提高,小麦开花期Pn在中等灌水量水平下,低施肥量处理较不施肥处理、中施肥量处理较低施肥量处理Pn分别显著提高2.45%和3.19%,Gs分别显著提高3.27%和4.23%,Tr分别显著提高4.26%和6.86%。4)同一水分条件下,灌浆期和成熟期生物量均随施肥量的增加先增后减,最高生物量出现在中等肥力水平(Y2)时;返青期和孕穗期,生物量随施肥量的增加逐渐增大。各灌水条件下,开花期生物量随施肥量的增加而变化趋势不同。【结论】高水(100mm)中肥(N、P_2O_5、K_2O用量分别为278.55,163.20,322.80kg/hm2)组合的小麦旗叶光合特性较为优良。     

不同CO2浓度和氮水平对冬小麦光合和生长特性的影响

为揭示高CO₂浓度处理下,不同氮水平对冬小麦光合作用、生物量积累和产量的影响,利用开顶式气室(OTC),以冬小麦品种宁麦13为试验材料,开展不同CO₂浓度(C,环境CO₂浓度;T,高CO₂浓度,比环境CO₂浓度高200 μmol·mol^-1)和氮水平(LN,低氮,90 kg·hm^-2;HN,高氮,240 kg·hm^-2)的交互试验,测定不同处理下不同生育期冬小麦的光合特性、叶片碳氮含量、地上部生物量和产量。结果表明,CO₂浓度升高提高了冬小麦的净光合速率,在低氮水平下增幅为78.4%,在高氮水平下增幅为77.2%。在开花期和灌浆期,高氮水平对冬小麦地上部干物质量积累有明显促进作用。各处理中,C-LN的产量最低,T-HN的产量最高,且二者差异显著(P<0.05)。以上结果说明,在未来CO₂浓度升高条件下,可通过增施适量的氮肥提升冬小麦的生物量和产量。     

低温下不同抗寒性冬小麦叶片组织结构比较

以强抗寒冬小麦品种东农冬麦1号和弱抗寒冬小麦品种济麦22为试材,应用光学显微镜和电子显微镜对不同低温下(5℃和-15℃)两个冬小麦品种的叶片显微、超微结构进行比较研究。结果表明,在5℃和-15℃低温下,东农冬麦1号和济麦22叶片的显微结构无明显差异,但超微结构差异较显著。东农冬麦1号类囊体基粒片层和基质片层跺叠整齐,沿叶绿体的长轴方向平行排列,而济麦22叶绿体内的类囊体排列方向无规则,与叶绿体长轴形成各种角度。在-15℃时,两个品种叶肉细胞的线粒体皆肿胀呈圆形,嵴的结构模糊,且济麦22有个别线粒体嵴消失现象。该研究结果可为冬小麦抗寒种质的选育提供理论依据。     

基于双波段光谱仪CGMD-302的小麦叶面积指数和叶干重监测

为探究双波段光谱仪CGMD-302在监测小麦长势上的可靠性与精准性,同时使用高光谱仪UniSpec SC与双波段光谱仪CGMD-302测试各生育时期小麦冠层信息,并定量分析了植被指数NDVI、RVI、DVI与叶面积指数和叶片干重之间的线性关系。结果表明,基于相同波段反射率计算出的高光谱仪植被指数和双波段光谱仪植被指数均能较好监测小麦群体长势。在CGMD-302监测的叶面积指数模型中,拟合方程的决定系数(R~2)均高于0.89,用以检验模型的均方根误差(RMSE)和相对误差(RE)分别小于0.792和0.225;叶片干重模型中,决定系数(R2)均高于0.85,用以检验模型的均方根误差(RMSE)和相对误差(RE)分别小于440kg/hm~2和0.239。通过分析发现,施氮270kg/hm~2既能保证产量又能兼顾品质,可作为适宜施氮量。适宜施氮量下,拔节期和孕穗期小麦适宜叶面积指数分别为:3.65±0.09和5.95±0.32;适宜叶干重分别为:(1 554±168)和(2 231±130)kg/hm~2。结合CGMD-302监测模型可推算出拔节期和孕穗期适宜冠层群体的植被指数区间并应用于冠层群体诊断。     

Effects of different agricultural treatments on narrowing winter wheat yield gap and nitrogen use efficiency in China

Under the limited cultivated land area and the pursuit of sustainable agricultural development,it is essential for the safety of grain production to study agricultural management approaches on narrowing the winter wheat yield gap and improving nitrogen use efficiency (NUE) in China.In this study,DSSAT-CERES-Wheat Model is used to simulate winter wheat yield under different agricultural treatments,and we analyze yield gaps and NUE with different management scenarios at regional scales and evaluate the suitable approaches for reducing yield gap and increasing NUE.The results show that,the potential of narrowing yield gap ranges 300–900 kg ha~(–1) with soil nutrients increase,400–1 200 kg ha~(–1) with sowing date adjustment and 0–400 kg ha~(–1) with planting density increase as well as 700–2 200 kg ha~(–1) with adding nitrogen fertilizer.Contribution rates of management measures of soil nutrients,sowing date adjusting,planting density,and nitrogen fertilizers are 5–15%,5–15%,0–4%,and 10–20%,respectively.Difference in nitrogen partial productivity ranges 3–10 kg kg~(–1) for soil nutrients,1–10 kg kg~(–1) for sowing date adjusting,1–5 kg kg~(–1) for planting density increase,and–12–0 kg kg~(–1) for adding nitrogen fertilizers,respectively.It indicates that four treatments can narrow yield gap and improve the NUE in varying degrees,but increasing nitrogen fertilizer leads to the decrease of NUE.     

基于多角度高光谱遥感的冬小麦叶片含水率估算模型

准确的作物水分监测对于旱情评估具有重要意义。在分析研究区冬小麦多角度光谱特征后,利用不同水分处理下冬小麦实测叶片含水率和实测多角度光谱数据,基于植被光谱指数法,建立不同观测角度下冬小麦光谱植被指数、水分敏感波段光谱指数与叶片含水率之间的数学模型。结果显示,相对方位角与相对天顶角越小时,观测到的光谱指数与叶片含水率的相关关系越优;敏感波段组合构建的光谱指数中,1450nm波段分别与其他波段组合的NDSI、RSI指数与叶片含水率相关性在各观测角度条件下均较好,1 450 nm波段是冬小麦叶片含水率研究的最佳敏感波段;选取常见的4种植被指数(NDVI、EVI、WI和NDII)中WI和NDVI在各观测角度下与叶片含水率的相关性优于其他两种指数,决定系数R2均在0.83以上,P0.01呈极显著相关;综上建立的多角度光谱叶片含水率估算模型,平均相对误差MRE均小于0.154、均方根误差RMSE均小于0.098,拟合效果较好,尤其是光谱指数NDSI1160,1450、NDSI980,1450和植被指数NDVI、WI;基于以上4种指数建立的最优观测角度(0°,30°)模型,其中植被指数WI的估算效果最好,相关系数在各角度均达到5%的相关显著水平,MRE0.03,可作为最优观测角度反演研究的最优植被指数。     

华北冬小麦开花及成熟期变化特征分析

利用华北平原59个农业气象观测站1981—2010年冬小麦生育期资料,分析了该区域冬小麦在气候变暖背景下开花期和成熟期的变化趋势特征。研究结果表明：近30年来,华北平原冬小麦开花期和成熟期均发生了明显变化。相对1980s而言,1990s开花期普遍提前2～5 d,成熟期提前1～6 d左右,2000s开花期则一般提前3～9 d,成熟期提前1～7 d左右。因此,随着年代推进,华北平原冬小麦开花期和成熟期提前趋势在进一步加剧。相对1980s而言,1990s生育期等值线普遍北移,而2000s等值线进一步北移的趋势更加明显。研究发现,3—5月月平均气温升高是开花期和成熟期提前的一个重要影响因素。     

不同生育期水分亏缺和施氮对冬小麦产量及水分利用效率的影响

【目的】研究不同生育期土壤水分亏缺和施氮对冬小麦产量及水分利用效率的影响,探讨小麦生长的水分亏缺敏感期和合理施氮量。【方法】以冬小麦小偃22为试验材料,设置4个氮肥水平和11个水分亏缺处理,采用盆栽试验,研究不同生育期水分亏缺和施氮水平对冬小麦水分利用效率、产量及其构成要素的影响。【结果】不同生育期土壤水分亏缺和施氮水平对冬小麦产量和水分利用效率有一定影响。与全生育期不亏水处理相比,返青期水分亏缺处理冬小麦干物质显著降低了7.70%,产量、水分利用效率显著增加了4.95%和7.56%;拔节期、抽穗期水分亏缺处理冬小麦干物质显著降低了13.69%,15.88%,产量显著降低了5.69%,8.06%,且对有效穗数、穗粒数也有显著降低作用;灌浆期水分亏缺对冬小麦产量影响不显著,但耗水量显著减少了5.44%,水分利用效率显著增加了8.02%。与全生育期不亏水处理相比,返青期+拔节期、返青期+抽穗期、返青期+灌浆期、拔节期+抽穗期、拔节期+灌浆期、抽穗期+灌浆期水分亏缺处理冬小麦干物质和产量均有显著降低,其中返青期+拔节期、拔节期+抽穗期水分亏缺处理冬小麦干物质显著降低了17.44%,17.57%,产量显著降低了11.60%和14.52%,水分利用效率显著降低了8.02%和7.56%,且对有效穗数、穗粒数也有显著降低作用。施氮对冬小麦产量和水分利用效率有显著促进作用。中氮处理(0.3 g/kg,N2)冬小麦产量最高,耗水量较低,水分利用效率较高。【结论】冬小麦对拔节期、抽穗期、返青期+拔节期、拔节期+抽穗期水分亏缺很敏感,中氮处理具有最高的产量和较高的水分利用效率。     

Estimating total leaf nitrogen concentration in winter wheat by canopy hyperspectral data and nitrogen vertical distribution

The use of remote sensing to monitor nitrogen(N) in crops is important for obtaining both economic benefit and ecological value because it helps to improve the efficiency of fertilization and reduces the ecological and environmental burden. In this study, we model the total leaf N concentration(TLNC) in winter wheat constructed from hyperspectral data by considering the vertical N distribution(VND). The field hyperspectral data of winter wheat acquired during the 2013–2014 growing season were used to construct and validate the model. The results show that:(1) the vertical distribution law of LNC was distinct, presenting a quadratic polynomial tendency from the top layer to the bottom layer.(2) The effective layer for remote sensing detection varied at different growth stages. The entire canopy, the three upper layers, the three upper layers, and the top layer are the effective layers at the jointing stage, flag leaf stage, flowering stages, and filling stage, respectively.(3) The TLNC model considering the VND has high predicting accuracy and stability. For models based on the greenness index(GI), mND705(modified normalized difference 705), and normalized difference vegetation index(NDVI), the values for the determining coefficient(R2), and normalized root mean square error(nRMSE) are 0.61 and 8.84%, 0.59 and 8.89%, and 0.53 and 9.37%, respectively. Therefore, the LNC model with VND provides an accurate and non-destructive method to monitor N levels in the field.     

Determination of critical nitrogen dilution curve based on leaf area index for winter wheat in the Guanzhong Plain,Northwest China

Excessive use of nitrogen(N) fertilizers in agricultural systems increases the cost of production and risk of environmental pollution. Therefore, determination of optimum N requirements for plant growth is necessary. Previous studies mostly established critical N dilution curves based on aboveground dry matter(DM) or leaf dry matter(LDM) and stem dry matter(SDM), to diagnose the N nutrition status of the whole plant. As these methods are time consuming, we investigated the more rapidly determined leaf area index(LAI) method to establish the critical nitrogen(N_c) dilution curve, and the curve was used to diagnose plant N status for winter wheat in Guanzhong Plain in Northwest China. Field experiments were conducted using four N fertilization levels(0, 105, 210 and 315 kg ha-1) applied to six wheat cultivars in the 2013–2014 and 2014–2015 growing seasons. LAI, DM, plant N concentration(PNC) and grain yield were determined. Data points from four cultivars were used for establishing the N_c curve and data points from the remaining two cultivars were used for validating the curve. The N_c dilution curve was validated for N-limiting and non-N-limiting growth conditions and there was good agreement between estimated and observed values. The N nutrition index(NNI) ranged from 0.41 to 1.25 and the accumulated plant N deficit(N_(and)) ranged from 60.38 to –17.92 kg ha~(-1) during the growing season. The relative grain yield was significantly affected by NNI and was adequately described with a parabolic function. The N_c curve based on LAI can be adopted as an alternative and more rapid approach to diagnose plant N status to support N fertilization decisions during the vegetative growth of winter wheat in Guanzhong Plain in Northwest China.     

施氮水平对冬小麦冠层氨挥发的影响

为探索冬小麦全生育期冠层氨挥发规律、主要影响因素及其对麦田氨挥发的贡献率,设置0、90、180 kg N·hm~(-2)三种氮素水平,利用改进型通气式氨气捕获装置,原位分析冬小麦冠层氨挥发速率及其与叶片氮素生理指标的关系。结果表明:麦田氨挥发主要发生在施肥后2~3周,全生育期累积挥发量为3.773~8.704 kg N·hm~(-2),施氮显著提高了麦田氨挥发累积量(P0.05),土壤与冠层氨挥发累积量分别为3.289~7.773 kg N·hm~(-2)和0.750~1.461 kg N·hm~(-2),对麦田氨挥发的贡献率分别为87.2%~89.3%和15.4%~19.9%。不施氮条件下,冠层无氨气吸收;低施氮(90 kg N·hm~(-2))下,冠层氨气吸收主要发生在苗期;高施氮(180 kg N·hm~(-2))下,苗期、返青期和灌浆前期冠层均有氨气吸收发生。冠层氨挥发主要发生在开花期、灌浆末期至枯死期,分别占冠层氨挥发的4.5%~9.3%和79.1%~99.0%;冠层氨挥发速率与叶片氨气补偿点、质外体NH+4浓度显著正相关(P0.05),与谷氨酰胺合成酶(GS)活性、质外体溶液pH相关关系不显著(P0.05)。总之,开花前,不施肥条件下冬小麦冠层向大气中释放氨,施肥后,冠层从大气中吸收氨。冬小麦开花后,不论施肥与否,冠层都向大气层释放氨。     

彩叶植物叶色变化及相关影响因子研究进展

彩叶植物的叶色表达受遗传因素和外部环境因子共同影响。文章从基因和遗传、彩叶形成中叶片生理生化变化、影响彩叶形成的生态因子、叶片结构及其他相关影响因子等几方面论述了国内外有关彩叶植物叶色表达的研究概况,并对彩叶植物今后的研究方向提出了展望,以期为彩叶植物叶色改良和新品种选育提供理论依据。     

基于数字图像技术的冬小麦不同施氮处理颜色特征分析

利用HSI颜色模型研究大田条件下不同施氮处理冬小麦群体数字图像的颜色特征,分析其与叶绿素含量、产量以及吸氮量之间的关系。结果表明:在孕穗至灌浆期前冬小麦群体的色调值H与叶片叶绿素含量(SPAD)存在显著的相关关系;从冬小麦群体色调值H的动态变化看,当生育前期监测到H由峰值开始下降时,可判断进入抽穗期,而生育后期H出现迅速下降时则表明冬小麦群体开始进入灌浆成熟期,数字图像的颜色特征能够反映冬小麦的生育进程;孕穗-开花期间H可以较好的反映作物产量,并建立了H值与冬小麦地上部生物量、籽粒产量之间的线性方程。     

Rapid determination of leaf water content for monitoring waterlogging in winter wheat based on hyperspectral parameters

Waterlogging is becoming an obvious constraint on food production due to the frequent occurrence of extremely high-level rainfall events. Leaf water content(LWC) is an important waterlogging indicator, and hyperspectral remote sensing provides a non-destructive, real-time and reliable method to determine LWC. Thus, based on a pot experiment, winter wheat was subjected to different gradients of waterlogging stress at the jointing stage. Leaf hyperspectral data and LWC were collected every 7 days after waterlogging treatment until the winter wheat was mature. Combined with methods such as vegetation index construction, correlation analysis, regression analysis, BP neural network(BPNN), etc., we found that the effect of waterlogging stress on LWC had the characteristics of hysteresis and all waterlogging stress led to the decrease of LWC. LWC decreased faster under severe stress than under slight stress, but the effect of long-term slight stress was greater than that of short-term severe stress. The sensitive spectral bands of LWC were located in the visible(VIS, 400–780 nm) and short-wave infrared(SWIR, 1 400–2 500 nm) regions. The BPNN Model with the original spectrum at 648 nm, the first derivative spectrum at 500 nm, the red edge position(λr), the new vegetation index RVI(437, 466), NDVI(437, 466) and NDVI′(747, 1 956) as independent variables was the best model for inverting the LWC of waterlogging in winter wheat(modeling set: R~2=0.889, RMSE=0.138; validation set: R~2=0.891, RMSE=0.518). These results have important theoretical significance and practical application value for the precise control of waterlogging stress.     

冬小麦叶角质层组分对菲和芘的吸附及影响

冬小麦叶面吸收多环芳烃（Polycyclic aromatic hydrocarbons,PAHs）途径内在机制及影响因素尚不清晰。本研究采用化学分离法将冬小麦叶角质层分为7个不同组分,通过比较不同角质层组分对菲和芘吸附的影响,揭示角质层分离组分的组成和结构对菲（Phenanthrene,PHE）和芘（Pyrene,PYR）吸收的作用机制。结果表明：冬小麦叶角质层中除可提取脂质蜡质外,还含有丰富的聚合脂质角质,其含量是蜡质的1.3倍。角质层中被糖类包裹的角碳并非连续分布,而角质则连续分布。角质层各组分元素组成存在较大差异,其非极性组分主要是角质,极性组分主要是糖类。冬小麦角质层4种组分对PHE的相对吸附系数大小顺序为：角碳>角质>角碳-糖类复合体>蜡质,对PYR的相对吸附系数大小顺序为：角质>角碳>角碳-糖类复合体>蜡质。这可能是由于角碳中芳香碳较为丰富,更易与PHE和PYR发生特殊的π-π吸附作用,而角质中含有较高水平的无定形石蜡,为PHE与角质中的柔性长烷基链基团之间的疏水作用提供了分配介质,由于蜡质含量较低,表现出较低的吸附系数。此外,角质层组分吸附系数与碳含量呈正线性相关,而与氧含量、极性指数呈显著负线性相关。研究表明,角碳和角质是PAHs的主要存储介质,由于角质层蜡质含量较低（9.6%）,蜡质组分对PAHs的吸附贡献最低。角质层组分碳含量越高,其对PAHs的吸附能力越强,而角质层组分氧含量和极性指数越高,其对PAHs的吸附能力越弱。     

黄淮海平原微喷灌下冬小麦农田水分渗漏及氮素淋失模拟分析

为了解黄淮海平原冬小麦水分渗漏和氮淋失特征,以优化小麦生产灌溉制度,降低农田水肥施用后土壤氮淋失对环境的影响,本试验于2020—2022年在设置不同灌水处理(充分灌溉、亏缺灌溉)和雨养处理的大田试验基础上,利用土壤-作物系统水热碳氮耦合(WHCNS)模型,通过优化土壤水力学和作物参数,评价模型适用性,并使用校验后的模型定量化分析不同水分管理条件下的农田氮淋失、水分渗漏及特征。结果表明：土壤含水率和硝态氮(以N计)的均方根误差范围分别为0.01～0.07 cm³·cm^-3和3.37～6.39 mg·kg^-1;叶面积指数和干物质量模拟R²≥0.9,一致性指数均≥0.7,模型模拟达到预期效果。使用校验后的模型对0～100cm土层水分渗漏和氮淋失进行动态模拟的结果显示,硝态氮淋失与水分渗漏动态一致,二者均表现为单日量小且持续时间较长,产生渗漏的累计天数占全生育期天数的59.2%～69.4%。与充分灌溉相比,亏缺灌溉在两季冬小麦产量无显著差异的情况下,日氮淋失和水分渗漏量分别减少3.88%～66.94%和37...     

不同肥力下生育后期干旱对冬小麦产量及水分利用效率的影响

采用防雨棚下池栽试验,研究了不同肥力下冬小麦生育后期水分亏缺对冬小麦产量及水分利用效率的影响.结果表明,冬小麦干物质积累量、千粒重、穗数、穗粒数、产量均随土壤肥力和含水量的提高而呈增加的趋势,且与全生育期充分灌溉相比,各干旱胁迫处理的干物质积累量、千粒重、穗数、穗粒数、产量的降幅均随土壤肥力的提高而减小,其中土壤水分含...