开花期渍水对小麦产量及氮素分配的影响

为探究江汉平原小麦生育期间雨水过多对小麦造成的影响,于2020-2021年以耐渍品种襄麦55和主推品种郑麦9023为供试材料开展大田试验,分析了开花期连续渍水7 d小麦产量、干物质和氮素积累与转运的变化。结果表明,与无渍水的对照（CK）相比,渍水导致小麦旗叶SPAD值下降。渍水后郑麦9023旗叶比襄麦55衰老更早,旗叶功能期相对更短。开花期渍水致使成熟期营养器官干物质和氮素积累量下降,促进花前储存的干物质和氮素在花后向籽粒的转运,提高了花前储存的干物质和氮素对籽粒产量和氮素的贡献率,但依然使成熟期单茎籽粒干物质和氮素积累量分别下降10.87%~13.59%和19.32%~23.60%。襄麦55成熟期茎鞘的干物质和氮素积累量下降量较大,花前干物质和氮素转运效率高于郑麦9023。开花期渍水影响籽粒灌浆速率和灌浆时间。渍水导致襄麦55最快灌浆期由花后21~35 d缩短至花后28~35 d,但单粒重下降不显著;渍水后郑麦9023灌浆在花后35 d时基本停止,单粒重下降显著。开花期渍水显著降低小麦产量,使襄麦55和郑麦9023分别减产7.7%和15.6%,减产主因分别是穗粒数和千粒重的显著下降。总之,开花期渍水会导致小麦减产,但促进了花前储存的干物质和氮素向籽粒的转运,对襄麦55花前干物质和氮素转运的影响大于郑麦9023。     

糯小麦灌浆期籽粒糖类、淀粉及蛋白质的动态研究

为了解糯小麦籽粒中糖类、淀粉和蛋白质在灌浆过程中的变化规律,明确灌浆过程中糯小麦籽粒糖类、淀粉、蛋白质含量变化与普通小麦之间的差异,在大田条件下,以糯麦12,糯麦1572两个糯小麦新品系为材料,以川育12、川育20、川麦42三个普通小麦品种为对照,研究了灌浆期间糯小麦籽粒中可溶性总糖、蔗糖、戊聚糖、果聚糖、淀粉、蛋白质含量及淀粉积累速率的动态变化.结果表明,在花后17～22 d,糯小麦淀粉的积累速率最高,蛋白质含量也达到最大,戊聚糖的含量是在花后22～27 d时达到峰值,果聚糖含量在花后7～12 d时最高.在灌浆过程中,糯小麦可溶性总糖、蔗糖、果聚糖、淀粉动态变化与普通小麦存在一定差异,但在蛋白质动态变化上则没有明显的差异.与普通小麦相比,糯小麦成熟籽粒总糖含量高,糯麦12的蔗糖含量显著高于普通小麦,两个糯小麦品系的戊聚糖含量均显著高于普通小麦川育12和川育20,糯麦1572的总淀粉含量显著低于三个普通小麦品种.在蛋白质和果聚糖含量上,糯小麦与普通小麦无显著差异.以上结果说明,可利用糯小麦籽粒各成分灌浆过程中与普通小麦存在差异这一特点,优化栽培措施,达到改善糯小麦品质的目的.     

花后高温胁迫对小麦籽粒产量和蛋白质含量的影响

为了筛选耐高温胁迫的优良小麦品种,采用盆栽与人工气候室相结合的方法,研究了花后高温胁迫对15个小麦品种产量和籽粒蛋白质含量的影响.结果表明,花后10 d和20 d高温处理分别使不同品种千粒重下降4.3%～34.8%和8.5%～32.5%,产量下降6.8%～35.0%和13.9%～37.9%,籽粒蛋白质含量增加1.0%～8.7%和2.4%～16.4%,表明不同品种对高温胁迫的敏感性存在明显差异.从高温处理时期来看,花后20 d高温胁迫的影响略大于花后10 d.依据花后高温胁迫下千粒重和产量的降幅进行聚类分析,将15个小麦品种划分为5类,其中洛旱6号受高温胁迫的影响较大,偃展4110、洛旱2号和郑麦366对高温胁迫的耐性较强.从籽粒蛋白质含量变化来看,豫麦50受高温胁迫影响较小,豫农949和豫农202受影响较大.     

不同品质类型小麦灌浆期旗叶Rubisco降解变化研究

为了解小麦籽粒蛋白品质的形成机制,以弱筋和强筋小麦为材料,研究了小麦灌浆期间旗叶叶绿素含量以及Rubisco （1,5二磷酸核酮糖羧化酶/加氧酶）降解的变化。结果表明,小麦灌浆期间不同品质类型品种旗叶叶绿素含量和Rubisco含量差异明显,弱筋小麦品种宁麦9号和扬麦15花后15~25 d旗叶叶绿素含量分别降低16.8%和19.6%,而强筋小麦品种郑麦9023和镇麦168花后15~25 d叶绿素含量下降幅度分别为52.8%和34.6%;旗叶灌浆期内肽酶活性呈先升高后降低的趋势,并且2个强筋品种花后5~25 d内肽酶活性始终高于2个弱筋品种;小麦旗叶Rubisco含量在开花后呈逐渐降低的趋势,但两个弱筋小麦品种旗叶中Rubisco含量始终高于两个强筋小麦品种。此外,扬麦15花后15～20 d才可以看出Rubisco亚基出现降解现象,郑麦9023在花后15 d就已经明显出现了Rubisco大亚基降解,说明强筋小麦郑麦9023旗叶较弱筋小麦扬麦15衰老早。     

花后干旱胁迫对两种筋力型小麦品种旗叶光合特性的影响

在盆栽防雨条件下,分别以强筋小麦品种豫麦34和弱筋小麦品种豫麦50为材料,研究了花后不同阶段（整个灌浆期、花后0～10d、花后10～20d和花后20～30d）土壤干旱胁迫（土壤相对含水量为35％～40％）对植株旗叶光合特性的影响。结果表明,花后不同阶段土壤干旱胁迫均导致两品种旗叶净光合速率（Pn）,PSⅡ活性（Fv/Fo）、PSⅡ最大光能转换效率（Fv/Fm）、实际光化学效率（ΦPSd）和光化学猝灭系数（qP）显著下降,非光化学猝灭系数（qN）显著上升;以整个灌浆期干旱胁迫下旗叶光合参数下降幅度最大。不同阶段相比,以花后10～20d干旱胁迫下旗叶光合参数的降幅最大,处理间差异达到极显著水平,而花后0～10d和20～30d干旱胁迫对旗叶光合参数的影响相对较小。因此,保证花后10～20d的麦田水分供应对维持小麦较高的光合性能、促进籽粒灌浆具有重要作用。两品种相比,以强筋小麦品种豫麦34旗叶光合性能及产量受干旱胁迫的影响相对较大。     

北京地区不同年代冬小麦品种籽粒微量元素含量的变化及其对水分的响应

为探讨北京地区小麦品种更替过程中籽粒微量元素含量的演变规律,选用20世纪60年代以来小麦品种更替过程中的7个主要推广品种,分别种植在春不浇水和春浇二水条件下,测定了小麦籽粒中Fe、Zn、Mn、Cu、蛋白质含量以及籽粒产量.结果表明,北京地区小麦品种更替过程中,随着产量的提高,籽粒微量元素含量并没有出现明显的稀释效应,而且有些营养成分含量(如Fe、Mn)随着年代更替出现明显提高的趋势;春不浇水降低了籽粒Fe、Zn、Cu和蛋白质含量,但提高了籽粒Mn含量.相关分析表明,小麦籽粒Fe、Zn、Cu含量与蛋白质含量呈正相关,Fe、Zn、Mn、Cu、蛋白质含量与籽粒产量、穗粒数和千粒重以及年代之间也呈正相关,说明在产量改良的过程中有望同步提高籽粒微量元素和蛋白质含量.     

施氮量对强筋小麦氮素积累和氮肥农学利用效率的影响

为探究冀东平原强筋小麦高产优质高效的最佳施氮量,在大田选用石优20号和中麦998两个强筋小麦品种,设置施氮量0 (N_0)、180 (N_1)和240 (N_2)kg·hm~(-2),研究了施氮量对强筋小麦氮素积累、转运和氮肥农学利用效率的效应。结果表明,小麦花前氮素积累量占成熟期植株地上部总氮素积累量的59%～66%,花后占34%～41%。随施氮量增加,小麦植株花前氮素积累量和转运量均提高,叶是花前氮素积累和转运的主要器官。小麦籽粒灌浆过程中,营养器官的氮素积累量逐渐下降,籽粒氮素积累量逐渐提高,营养器官氮素转运高峰与籽粒氮素积累高峰一致,石优20号为花后14～21d,中麦998为花后7～21d。施氮量从180 kg·hm~(-2)增加到240kg·hm~(-2),石优20号和中麦998的产量分别提高了6.10%和7.58%,籽粒蛋白质含量分别提高了3.68%和3.73%,而氮肥农学利用效率分别降低了25.68%和23.93%。综上所述,促进花前氮素的积累和转运可提高强筋小麦蛋白质含量;适当减少施氮量可实现强筋小麦的提质增效。本试验条件下,冀东平原强筋小麦生产的适宜施氮量为180kg·hm~(-2)。     

灌浆期高温干旱胁迫对小麦籽粒淀粉积累的影响

为探讨花后高温和干旱逆境胁迫对小麦淀粉组分的影响,采用盆栽和人工气候室相结合的方式研究了灌浆期短暂高温、干旱及其复合胁迫对两个不同品质类型小麦品种籽粒总淀粉、直链淀粉和支链淀粉含量的影响。结果表明,小麦籽粒淀粉的积累量符合Logistic方程,但逆境胁迫会缩短籽粒淀粉积累持续时间,降低其积累速率,使其最终淀粉积累量减少。与对照相比,高温、干旱及其复合胁迫显著降低两个小麦品种籽粒的支链淀粉和总淀粉含量,直链淀粉含量受影响较小,淀粉的直/支比增加。高温、干旱及其复合胁迫下,洛麦24的千粒重分别较对照下降42.03%、21.95%和50.01%,产量分别较对照下降57.88%、40.75%和61.08%;郑麦366的千粒重分别较对照下降34.39%、7.64%和43.16%,产量分别较对照下降41.58%、30.97%和48.49%。综上所述,高温、干旱胁迫抑制支链淀粉积累是造成产量下降的重要原因;复合胁迫对小麦籽粒淀粉积累量的影响大于干旱或高温单独胁迫;高温胁迫的影响大于干旱;洛麦24较郑麦366对高温和干旱胁迫更敏感。     

增铵营养对专用型小麦可溶性糖转运及淀粉积累的影响

为给小麦氮肥管理提供理论依据,选用强筋小麦品种郑麦9023和弱筋小麦品种郑麦004为材料,在大田试验条件下研究了增铵营养对不同专用型小麦旗叶、籽粒可溶性糖含量与籽粒中淀粉及其组分含量的影响。结果表明,增铵营养条件下,两种小麦旗叶、籽粒中可溶性糖含量与籽粒淀粉及其组分含量在灌浆期间的变化趋势基本一致,但在灌浆中后期差别较大,与郑麦9023相比,郑麦004对增铵营养的响应更为显著。在NO3-∶NH4+为50∶50时小麦旗叶、籽粒可溶性糖含量变化及淀粉积累增加最显著。在此处理下,花后24d郑麦9023和郑麦004旗叶可溶性糖含量分别增加了7%和21%;增铵营养对两个小麦品种淀粉组分支/直比例影响不一,与对照相比,增铵营养导致郑麦9023下降了3.2%,使郑麦004增长了1.1%。增铵营养可能主要通过增加小麦旗叶中可溶性糖含量促进籽粒淀粉积累,与强筋小麦品种郑麦9023相比,弱筋小麦品种郑麦004的各项指标表现更为优异。     

花后叶面喷施氮肥和锌肥对小麦粒重及营养品质的影响

为了解小麦花后叶面喷施氮、锌肥对粒重及营养品质的改善作用及品种间的响应差异,以黄淮麦区20个小麦品种为材料,分析了花后喷施氮肥或锌肥后小麦粒重、植酸含量、Fe、Zn、Mg元素含量及其生物有效性的变化.结果表明,花后喷锌、氮均可增加小麦千粒重和籽粒蛋白质含量,其中喷氮对籽粒蛋白质含量的提高效果大于锌肥.喷锌可使小麦籽粒植酸含量下降,其中品种955159降幅达27.95％;而喷氮对籽粒植酸含量影响较小.喷锌显著提高籽粒中Zn含量,平均增幅54.38％;喷氮则可以显著提高籽粒中Fe和Zn含量,平均增幅分别为36.88％和11.25％,但降低了籽粒中Mg含量.喷锌可提高籽粒Zn的生物有效性,而喷氮可提高籽粒Fe的生物有效性.说明在小麦生育后期合理喷施氮肥和锌肥可以同时提高粒重及矿质元素含量和有效性,从而改善籽粒营养品质.     

Characterization of starches of proso,foxtail, barnyard,kodo, and little millets

Scanning electron microscope (SEM) pictures of small millet starch granules showed more large polygonal and few small spherical or polygonal granules. The granules of small millets resembled those of rice starch granules. The size of the starch granules ranged from 0.8–10 m. The size of the granules was larger in barnyard millet and smaller in proso millet. Several granules showed deep indentation caused by protein bodies. SEM of starch isolated from 24 hour-germinated kodo millet showed pitting or pinholes at some points due to the attack of amylases (preferentially on bigger granules). Brabender viscoamylograph studies on small millet starches revealed that the gelatinization temperatures ranged from 75.8 to 84.9 ^° C. Barnyard millet possessed lower amylograph viscosity, minimum breakdown, and relative breakdown values when compared to the other small millets.     

Effects of application of nitrogen fertilizer on concentrations of P, K, S, Ca, Mg, Na, Cl, Mn, Fe, Cu and Zn in perennial ryegrass/white clover pastures in south-western Victoria, Australia

Effects of timing and rate of N fertilizer application on concentrations of P, K, S, Ca, Mg, Na, Cl, Mn, Fe, Cu and Zn in herbage from perennial ryegrass/white clover pastures were studied at two sites in south-western Victoria, Australia. Nitrogen fertilizer (0, 15, 25, 30, 45 and 60 kg ha^–1) was applied as urea in mid-April, early May, mid-May, early June and mid-June 1996 to pastures grazed by dairy cows. At Site 1, N fertilizer resulted in a linear increase in P, K, S, Mg and Cl concentrations in herbage and a linear decrease in Ca concentration. For all times of application, concentrations of P, K, Ca, Mg and Cl in herbage increased by 0·0048, 0·08, −0·010, 0·0013 and 0·053 g kg^–1 dry matter (DM) per kg N applied respectively. For S concentration, maximum responses occurred in mid-May (0·012 g kg^–1 DM per kg N applied). At Site 2, N fertilizer resulted in a linear increase in P, S and Na concentrations in herbage, a linear decrease in Ca concentration and a curvilinear increase in K and Cl concentration. The maximum responses for P, S and K concentrations in herbage occurred for the N application in mid-June and were 0·015, 0·008 and 0·47 g kg^–1 DM per kg N applied respectively. For Cl concentration, the maximum response occurred for the N application in early June and was 0·225 g kg^–1 DM per kg N applied. Overall, applications of N fertilizer up to 60 kg ha^–1 did not alter herbage mineral concentration to levels that might affect pasture growth or animal health.     

Milling,functional and thermo-mechanical properties of wheat,rye, triticale,barley and oat

The milling potential of hulled barley, hulled oat, triticale, rye and wheat was studied using a long tempering process and a laboratory four-roller mill. Regardless of the investigated cereal, the results indicated a significant influence (p < 0.05) of volume per surface area ratio on the milling yield and ash contents of the flour. The lowest milling yield was obtained in case of hulled oat. Solvent retention capacity profiles were determined for all investigated whole cereals and flours for predicting the contribution of different polymers to the functionality of samples. For all solvents higher values were obtained for the whole cereals compared to the corresponding flour. Thermo-mechanical properties of the whole cereals and refined flours were also investigated. If in case of wheat the gluten proteins play an essential role on dough behaviour during kneading at 30 °C, in case of triticale, rye, hulled barley and hulled oat, the fibers play a major role as well. Thermo-mechanical properties of starch registered a large variation between cereals and/or flours. The lowest torque value corresponding to starch gelatinization (C3) was registered in case of the hulled oat flour, 1.92 Nm, while the highest value in case of rye flour, 2.65 Nm.     

Evaluation of the enzyme-amplified ELISA for the detection of potato viruses A,M, S,X, Y,and leafroll

Various parameters,e.g. types of microtiter plate for DAS-ELISA (double antibody sandwich-enzyme-linked immunosorbent assay), use of fresh or frozen amplifier solutions for enzyme-amplified-ELISA, and use of sodium diethyldithiocarbamate (NaDIECA) in sample buffer in cocktail-ELISA were evaluated for the detection of potato viruses A, M, S, X, Y and leafroll from potato foliage. Dynatech Immulon immunoplates provided higher readings for all viruses. Fresh amplifier solution in amplifed-ELISA was superior to frozen solutions. Amplified ELISA gave only marginal improvement in the sensitivity over the standard DAS-ELISA. Addition of NaDIECA in sample buffer did not improve the detection of viruses in DAS-, amplified-, or cocktail-ELISA. Cocktail-ELISA can reduce antigen incubation time to as short as 15 min for PVA, PVM and PVX; 1 hr for PVY and PLRV; and 2–4 hr for PVS using pre-coated plates. Although amplified-ELISA is slightly more sensitive than DAS-ELISA for certain potato viruses, it is not suitable for large-scale indexing of potato viruses in Seed Certification Laboratories, in view of the additional steps needed in carrying out this procedure.     

Study of antimicrobial activity of aloevera, chitosan, and curcumin on cotton, wool, and rabbit hair

Aloevera, chitosan, and curcumin were applied in alone and in combination with each others on cotton, wool and rabbit hair by exhaustion method for the assessment of their antimicrobial activity. The antimicrobial activity of these natural ingredients was better in peroxide treated cotton, formic acid treated wool/rabbit hair fibrous substrates than their corresponding intact ones. Aloevera shown better antimicrobial activity than chitosan and curcumin when applied alone and its antimicrobial activity was enhanced by addition of both chitosan and curcumin. The application of aloevera+chitosan+curcumin combination on peroxide treated cotton and formic acid treated wool/rabbit hair fibrous substrate was fast up to twenty five washing cycles.     

Response of permanent and reseeded grassland to fertilizer nitrogen. 2. Effects on concentrations of Ca, Mg, K, Na, S, P, Mn, Zn, Cu, Co and Mo in herbage at a range of sites

The concentration of mineral elements in herbage from permanent swards of mixed species composition (predominantly Agrostis spp., Holcus lanatus, Festuca rubra, Lolium perenne, Poa spp., etc.) was compared with that from sown perennial ryegrass ( Lolium perenne ) at two fertilizer rates (0 and 300kg N ha⁻¹ year⁻¹, both with P and K) and with L. perennel Trifolium repens (at 0 N with P and K). The investigation was conducted over four years at sixteen contrasting sites in England and Wales. Herbage samples for mineral analysis were taken at first and fourth harvests (May and August) each year from plots under 4-weekly cutting. There was a wide degree of variation between sites, particularly for concentrations of Ca, Mg, Na and all trace elements analysed. Herbage from L. perenne reseeds had significantly higher concentrations of Ca, Mg, Na, Co and S, but K, Mo, Zn, Cu and P were generally lower than in the permanent swards. L. perennel T. repens swards had the highest concentration of major cations, but trace element levels were generally intermediate between those for 0 N permanent and L. perenne swards. Fertilizer N reduced concentrations of Ca, Mn, Mo and S, and increased Mg, Na and Zn, with no consistent effects on K, Co and Cu. Herbage at harvest 4, compared with harvest 1, had higher Ca, Mg, Na, Mn, Zn and S. Permanent and L. perenne swards responded similarly to fertilizer N and between harvest dates. Results are discussed in relation to previous reports of botanical and fertilizer effects on mineral concentrations, and the mineral requirements of livestock. Changes in mineral concentration resulting from reseeding permanent swards are considered unlikely to increase mineral-related livestock disorders, and in many cases could be beneficial, though problems might arise on sites where some elements, e.g. Cu and Mg, are low.