Study on the response of wheat to lead, cadmium and zinc

The effect of lead, cadmium and zinc on the transcriptions and structures of 5 DNA fragments was studied by RNA slot blot hybridization and the analysis of restriction fragment length polymorphism (RFLP). The seeds of three wheat strains (Yunmai29, 1257, 5118) which had grown in contaminated area, Huize Lead Zinc Mine, Yunnan Province of China and in uncontaminated area were taken as the experimental materials. No obvious change of DNA structure was detected, but there were many differences in the DNA transcription levels. These results implied that lead, cadmium and zinc might inhibit DNA transcription and had much more effect on gene expression than structure in wheat, which might acclimate to metal pollution after having grown in pollution area for a long time and the interference of these metal ions in gene expression might be one of main mechanisms of metal toxicity and plant adaptation. The results also showed the microevolution of wheat in the lead zinc mine.

Absorption,Accumulation and Distribution of Zinc in Highly-Yielding Winter Wheat

Zinc（Zn） is an important essential microelement for wheat.In order to study the characteristics of Zn absorption,accumulation and distribution in highly-yielding winter wheat（with a grain yield of 9 000 kg ha-1）,field experiments were conducted in Gaocheng County of Hebei Province,China.Four winter wheat cultivars,i.e.,Shimai 14,Jifeng 703,Shimai 12,and Shixin 828,and four cultivars,i.e.,Temai 1,Shimai 12,Shixin 531,and Shixin 828,were used in the experiment,during 2004-2005 and 2005-2006,respectively.Plant samples were taken from the plots at each growing stage for Zn concentration analysis.The main results showed that the concentration of Zn in various above-ground organs of wheat was 9.5-112.5 mg kg-1 at different growing stages.The organ with the highest Zn concentration differed with the change of growth center at different growing stages.Accumulation of Zn in leaf blades was the highest among all the organs during early growing period,and more than 50% of the Zn accumulation was distributed to leaf blades before jointing,and higher than that to other organs.In late growing period,however,the accumulation of Zn in grains was the highest,and 58.1% of the Zn accumulation was distributed in grains at maturity.The total accumulation of Zn in wheat plant during its life span ranged from 384.9 to 475.9 g ha-1.The amount of Zn required for the formation of 100 kg grain yield ranged from 4.3 to 5.2 g.All the organs were ordered in such a sequence that leaf blades 〉 spikes 〉 leaf sheaths 〉 stems according to their net absorption and transportation of Zn as well as their contribution to Zn accumulation in grains.58.2-60.3% of the Zn accumulated in grains was redistributed from other organs,mostly from leaf blades.Concentration and accumulation of Zn in all the organs of wheat was high during early and middle growing periods,while accumulation of Zn in grains during late growing period mainly depended on the redistribution from other organs.According to these characteristics of Zn absorption and accumulation,Zn should be applied as seed dressing or basal fertilizer,so as to accelerate the early growth and Zn absorption of wheat.

Expression Pattern Analysis of Zinc Finger Protein Genes in Wheat(Triticum aestivum L.) Under Phosphorus Deprivation

Zinc finger protein（ZFP） genes comprise a large and diverse gene family, and are involved in biotic and abiotic stress responses in plants. In this study, a total of 126 ZFP genes classified into various types in wheat were characterized and subjected to expression pattern analysis under inorganic phosphate（Pi） deprivation. The wheat ZFP genes and their corresponding GenBank numbers were obtained from the information of a 4×44K wheat gene expression microarray chip. They were confirmed by sequence similarity analysis and named based on their homologs in Brachypodium distachyon or Oriza sativa. Expression analysis based on the microarray chip revealed that these ZFP genes are categorized into 11 classes according to their gene expression patterns in a 24-h of Pi deprivation regime. Among them, ten genes were differentially up-regulated, ten genes differentially downregulated, and two genes both differentially up- and down-regulated by Pi deprivation. The differentially up- or down-regulated genes exhibited significantly more or less transcripts at one, two, or all of the checking time points（1, 6, and 24 h） of Pi stress in comparison with those of normal growth, respectively. The both differentially up- and down-regulated genes exhibited contrasting expression patterns, of these, TaWRKY70;5 showed significantly up-regulated at 1 and 6 h and down-regulated at 24 h whereas TaAN1AN20-8;2 displayed significantly upregulated at 1 h and downregulated at 6 h under deprivation Pi condition. Real time PCR analysis confirmed the expression patterns of the differentially expressed genes obtained by the microarray chip. Our results indicate that numerous ZFP genes in wheat respond to Pi deprivation and have provided further insight into the molecular basis that plants respond to Pi deprivation mediated by the ZFP gene family.

The Effects of Three Mineral Nitrogen Sources and Zinc on Maize and Wheat Straw Decomposition and Soil Organic Carbon

The incorporation of straw in cultivated ifelds can potentially improve soil quality and crop yield. However, the presence of recalcitrant carbon compounds in straw slow its decomposition rate. The objective of this study was to determine the effects of different nitrogen sources, with and without the application of zinc, on straw decomposition and soil quality. Soils were treated with three different nitrogen sources, with and without zinc： urea （CO（NH2）2）, ammonium sulfate （（NH4）2SO4）, and ammonium chloride （NH4Cl）. The combined treatments were as follows：maize （M） and wheat （W） straw incorporated into urea-, ammonium sulfate-, or ammonium chloride-treated soil （U, S, and C, respectively） with and without zinc （Z） （MU, MUZ, WU, WUZ;MS, MSZ, WS, WSZ;MC, MCZ, WC, WCZ, respectively）;straw with zinc only （MZ, WZ）;straw with untreated soil （MS, WS）;and soil-only or control conditions （NT）. The experiment consisted of 17 treatments with four replications. Each pot contained 150 g soil and 1.125 g straw, had a moisture content of 80%of the ifeld capacity, and was incubated for 53 days at 25°C. The rates of CO2-C emission, cumulative CO2-C evolution, total CO2 production in the soils of different treatments were measured to infer decomposition rates. The total organic carbon （TOC）, labile organic carbon （LOC）, and soil microbial biomass in the soils of different treatments were measured to infer soil quality. All results were signiifcantly different （P〈0.05） with the exception of the labile organic carbon （LOC）. The maize and wheat straw showed different patterns in CO2 evolution rates. For both straw types, Zn had a synergic effect with U, but an antagonistic effect with the other N sources as determined by the total CO2 produced. The MUZ treatment showed the highest decomposition rate and cumulative CO2 concentration （1 120.29 mg/pot）, whereas the WACZ treatment had the lowest cumulative CO2 concentration （1 040.57 mg/pot）. The addition of NH4Cl resulted in the highest total organic carbon （TOC） concentration （11.59 mg kg-1）. The incorporation of wheat straw resulted in higher microbial biomass accumulation in soils relative to that of the maize straw application. The results demonstrate that mineral N sources can affect the ability of microorganisms to decompose straw, as well as the soil carbon concentrations.

Impact of Different Zinc Application Methods on Yield and Yield Components of Various Wheat (<i>Triticum aestivum</i>L.) Cultivars

To evaluate the impact of different zinc application methods on yield and yield components of various wheat cultivars, a field experiment was carried out at Student’s Farm, Department of Agronomy, University of Agriculture Faisalabad, during winter 2014-2015. The experiment was laid out in RCBD (Randomized Complete Block Design) with factorial arrangement. In this experiment, all the treatments were replicated three times, using the net plot size of 1.8 m × 5.0 m. The experiment comprised of two factors. Factor A consists of two varieties: Faisalabad-2008 and Punjab-2011. While, Factor B consists of different methods of zinc application, control, zinc application in soil before planting 23 kg·ha-1, zinc foliar application, 4% ZnSO4 solution at two stages (tillering and stem elongation stage). The data regarding different parameters were collected and analyzed from the crop using standard procedures. Regarding the impact of zinc application method maximum plant height at maturity (103.6 cm), total number of tillers (564.67 m-2), spike length (10.83 cm), number of spikelets spike-1 (19.50), number of grains spike-1 (50.36), 1000-grain weight (34.16 g), biological yield (11.93 t·ha-1), grain yield (6.00 t·ha-1) and harvest index (39.25%) were recorded in treatment where zinc was applied both in the soil before planting and by foliar application on later growth stages. Similarly, grain zinc contents (33.11 mg·kg-1), grain protein contents (10.1%) and grain carbohydrate contents (64.23%) were also observed in the treatment where zinc was applied both in the soil before planting and by foliar application on later growth stages, which is better than all other treatments. In case of wheat varieties, Faisalabad-2008 performed better than Punjab-2011, with maximum method maximum total number of tillers (460.67 m-2), spike length (9.70 cm), number of grains spike-1 (48.80), 1000-grain weight (33.81 g), biological yield (10.32 t·ha-1), grain yield (5.0 t·ha-1) and harvest index (33.93%). It is concluded that sowing of wheat cultivar Faisalabad-2008 + application of zinc in soil before planting with foliar application at later stages (tillering and stem elongation stage) of wheat could give better results in terms of yield.

Positive and Negative Environmental Effect of Using Zinc Oxide Nanoparticles on Wheat under Drought Stress

Nanoscience is a development concept in the field of agriculture. Water scarcity is one of the most serious stresses that restrict growth of plant. This search was done to value the positive and negative influence of ZnO nanoparticles on wheat plant growth under drought stress. A green synthesis technique was used to produce pollutant-free nano structures. A field experiment was carried out during successive season (2019/2020). NP-Zn-O was applied either by seed-soaking, foliar spraying, or both together applications. The dose of ZnO NPs was 100 mg/l. Data showed that drought stress reduced the grain and shoot wheat yield. The use of different forms of ZnO improved the grain and shoot wheat yield, these increases reached 1.16-, 1.54-fold that control. In addition, one of the other effects of Zn-O-NPs is to increase the levels of chlorophyll and proline antioxidants in plant tissues, as it is a cofactor for enzymes such as superoxide dismutase and catalase. The data suggest that the role of ZnO NPs is not only to improve plant growth and physiological parameters, but also to improve nutrient uptake and plant nutrient levels. In this regard, the use of zinc in the form of ZnO NPs has a positive effect on reducing the adverse effects of drought conditions and improving the nutritional quality of plants.

我国新育成小麦品种(系)籽粒锌含量及影响因素

【目的】明确我国主要麦区新育成高产小麦品种(系)籽粒、面粉和麸皮的锌含量,探究产量、产量构成、锌吸收分配及土壤因素对小麦籽粒中锌含量的影响,为我国小麦新品种(系)的锌营养强化提供依据。【方法】在2021—2022、2022—2023年两个小麦生长季,依托国家小麦产业技术体系在我国4个主要麦区17个省(市)布置的104个新育成小麦品种(系)田间多点试验,测定了成熟期小麦籽粒、面粉和麸皮锌含量、产量及其构成、锌吸收分配特征和土壤理化性质,统计了氮、磷、钾肥施用量,并以此探析我国新育小麦品种(系)籽粒不同组分锌含量、吸收分配特征及其环境影响因素。【结果】我国小麦新品种(系)籽粒锌含量介于14.3~54.7 mg/kg,平均27.6 mg/kg;面粉锌含量介于1.4~30.2 mg/kg,平均9.0 mg/kg;麸皮锌含量介于23.2~107.6 mg/kg,平均55.9 mg/kg。籽粒锌含量每提高1.0 mg/kg,面粉锌含量提高0.2~0.3 mg/kg,麸皮锌含量提高1.9~2.3 mg/kg。长江中下游麦区和西南麦区的小麦品种(系)籽粒及其各组分中锌含量高于黄淮南北片麦区。小麦品种(系)籽粒锌含量与产量、生物量和穗数呈负相关,与籽粒锌吸收量和收获指数呈正相关,与茎叶、颖壳和麸皮锌吸收量呈负相关。籽粒中锌含量与钙和硫含量呈负相关,与铁和铜含量呈正相关。小麦新品种(系)籽粒及其各组分中锌含量因地点而异,土壤pH、土壤有效锌和铁是影响小麦籽粒锌含量的主要因素。籽粒锌含量与土壤pH呈负相关,与土壤有效锌和铁呈正相关;回归分析结果表明,在pH低于6.3、有效锌高于1.7 mg/kg的土壤上,籽粒锌含量可达到强化水平40.0 mg/kg。【结论】我国新育成小麦品种(系)的籽粒、面粉及麸皮中,锌的平均含量分别为27.6、9.0和55.9 mg/kg。影响籽粒各组分锌营养的主要因素在作物方面包括产量、穗数以及茎叶、颖壳和麸皮中的锌积累量;在土壤方面则涉及土壤的pH值、有效铁含量和锌含量。在选育高产且优质的小麦品种时,应着重培育根系锌吸收能力强、穗粒数多且千粒重较大的品种,并通过合理施肥进一步强化面粉的锌营养。

Effect of Zn application methods on Zn distribution and bioavailability in wheat pearling fractions of two wheat genotypes

Pearling is an effective method for evaluating the distribution of chemical components in wheat grain. Five pearling fractions （representing approximately 20% of the original sample weight） of wheat grain were obtained using the JNMJ3 rice polisher for two cultivars with different methods of Zinc （Zn） application; the residual portion （approximately 80%） was ground as flour. Results showed that folJar or soil＋foliar Zn application methods effectively increased Zn concentrations and bioavailability in whole grain and pearling fractions, but soil Zn application was ineffective in field conditions. In addition, the concentrations of Zn, Fe, Mn and Cu within wheat grain showed a diminishing trend from the outer layer to the inner portions of the wheat grain as the pearling level increased. These results cleady showed the distribution of minerals in wheat grain, especially in the outer part of the grain （bran）. The results also suggest that precise milling techniques combined with foliar Zn ap- plication could improve the Zn and Fe nutritional qualities of consumed flour and mitigate human Zn and Fe deficiencies.

基于深度学习的小麦籽粒锌含量预测及安全利用分区

为实现对小麦籽粒Zn含量的精准预测及安全利用分区,以济宁南部小麦种植区为研究对象,采集并测定了小麦籽粒中Zn及根际土壤样品中SiO_(2)、Fe_(2)O_(3)、MgO、CaO、Na_(2)O、K_(2)O、OrgC、P、N、S、Zn和pH等12种理化指标的含量,系统研究了小麦籽粒中Zn含量及其根际土壤理化指标含量特征,利用多层感知机神经网络和随机森林模型对小麦籽粒Zn含量变化特征进行预测,选择最优模型预测出济宁南部区域小麦籽粒Zn含量,并结合GIS技术划分了贫锌、缺锌、足锌和富锌农田。结果表明:济宁南部区域小麦籽粒中Zn含量平均值(39.7 mg·kg^(-1))与富锌小麦籽粒推荐值基本持平,超出黄淮麦区小麦籽粒Zn平均含量1.32倍;经相关分析和聚类分析得出,小麦籽粒Zn与根际土壤理化指标之间相互作用、相互耦合,存在着较为复杂的非线性关系;多层感知机神经网络预测模型的R^(2)(0.999)、RMSE(0.194)和MAE(0.146)等评价指标均优于随机森林模型;根际土壤中P、pH、OrgC和N指标是影响多层感知机神经网络预测相对重要的特征变量;研究区以足锌农田和缺锌农田为主,面积占比分别为57.47%和33.97%,谨慎利用贫锌区和安全利用富锌区农田面积占比分别为6.05%和2.51%。通过深度学习与农业地质相结合,利用多层感知机神经网络实现了通过简单土壤理化指标精准预测小麦籽粒锌含量。

锌影响小麦产量及品质的研究进展

全球范围内土壤缺锌问题对作物产量及品质构成了严重威胁,进而影响人体健康。本文结合国内外文献阐明小麦锌含量水平对人体健康的影响,探讨了影响小麦籽粒锌含量与土壤锌含量的主要因素及小麦对于锌的吸收、锌对于小麦生长发育及产量品质的作用,并提出有效提高小麦籽粒锌含量的对策。缺锌土壤中施用锌肥能有效提高小麦产量及品质;小麦籽粒锌含量会受到土壤水分、土壤有机质、土壤碳酸钙含量、土壤pH值等多方面因素影响;土施锌肥、喷施锌肥、土肥与喷肥相结合是有效提高小麦产量及品质的重要施用方式。未来研究应聚焦于施肥-土壤-作物体系中籽粒锌含量调控的农学因素分析,以提出提高小麦籽粒锌营养的合理建议。

石灰性土壤小麦籽粒锌硒生物强化理论技术与推广面临的挑战

锌与硒是人类生命活动必需的两种微量元素,摄入不足会引发多种疾病。我国小麦主产区恰好处于锌硒缺乏或潜在缺乏的石灰性土壤地带,籽粒中锌硒含量难以达到人体需求标准,导致缺锌缺硒人口数量庞大,已成为我国严重的公共营养与健康问题。本文综述了小麦籽粒锌硒农艺生物强化措施,强化籽粒中锌硒的分布、安全形态、生物可给性及叶面喷施的应用现状。国内外研究大多认为,在极缺锌土壤上采用土施或土施与叶面喷施锌肥结合的方式是最有效的小麦锌强化策略;而最新研究表明,在我国潜在缺锌的石灰性土壤上,叶面喷施硫酸锌的强化效果远优于土施,在小麦灌浆前期喷施2~3次0.3%~0.4%的Zn SO_(4)·7H_(2)O (喷锌总量约2.5 kg/hm^(2))并添加表面活性剂,可以实现籽粒锌含量达40~60 mg/kg的富锌目标。小麦籽粒中锌含量由外到内逐渐降低,人体摄入最多的中心胚乳部分锌含量最低,故需更为关注胚乳中锌含量及生物有效性,制定胚乳富锌标准。此外,食物中无机态元素毒性较大,生物有效性低,吸收利用效果不理想,而有机态对人体更为安全有效,因此还需明晰强化小麦籽粒中是否将外源无机Zn转化为有机态储存。小麦硒生物强化通过土施或叶面喷施亚硒酸盐或硒酸盐均能实现,由于土施硒肥易受土壤pH、有机质等因素影响,硒肥利用率低,因此,通行的硒强化措施是在小麦灌浆前期,喷施2 0~3 0 g/h m 2的亚硒酸钠或硒酸钠,能够实现籽粒硒含量达0.2 5~0.30 mg/kg的富硒目标。与锌不同,硒在籽粒中分布相对均匀,胚乳中硒占全粒总硒的96.2%~97.4%。同时硒强化小麦籽粒中对人体安全的有机硒占总硒的80%以上,且不同有机硒在人体中的作用不同。虽然叶面单独喷锌或硒的理论技术体系完善且实际强化效果良好,但其经济效益没有充分体现,影响了该技术的应用推广。近年来,将叶面喷施锌硒与“一喷三防”农艺措施相结合的研究不断增多,与小麦实际生产形成有效对接,为小麦锌硒强化提供了可行途径。然而,锌硒与不同农药及多种微量元素共同喷施时多种物质之间的互作效应,叶面喷施进行锌硒生物强化及籽粒锌硒储存的生理及分子机制还未明晰,值得进一步探讨。

土壤镉污染和叶面施锌对小麦不同部位镉锌含量的影响

为了探究土壤镉污染和叶面施锌对小麦地上部各器官镉锌含量的影响,以宁麦21、扬辐麦4号和镇麦12号为试材,设置对照、土壤镉处理(5mg·kg^(-1))、叶面施锌(0.2%ZnSO_(4))和土壤镉处理+叶面施锌4个处理,研究镉锌互作对小麦生长和产量及植株各器官镉锌含量、积累与转运的影响。结果表明:土壤镉污染、抽穗始期两次叶面施锌对不同品种小麦生长和产量性状(SPAD值除外)均无显著影响。镉污染使供试小麦籽粒、茎秆、叶片、穗轴和颖壳的镉含量(17~65倍)和累积量(17~64倍)均大幅增加。叶面施锌显著增加了不同品种小麦各器官锌含量(>61%)和累积量(>58%)。叶面施锌对小麦地上部总镉累积量无影响,但改变了镉在不同器官间的分布情况,喷锌使镉污染小麦籽粒镉含量显著降低10%,但使茎秆、叶片和穗轴镉含量显著增加12%~55%。喷锌处理使镉污染植株麦草向籽粒镉转运系数显著下降(15%~31%),但镉污染对锌的转运系数无明显影响。统计分析表明,镉处理、锌处理及其互作对小麦镉、锌含量的影响多存在不同程度的品种和部位依赖。综上所述表明,5mg·kg^(-1)镉污染对各供试品种小麦产量均无明显影响,但籽粒及麦草镉含量均大幅增加,叶面施锌在显著降低可食用部位镉含量的同时亦增加了饲用部位镉含量,变幅多因品种而异。

旱地小麦锌吸收转移与籽粒锌含量的关系

【目的】黄土高原旱地小麦籽粒锌含量较低,明确土施锌肥引起的小麦花前花后锌吸收转移和籽粒锌含量的变化,及其与土壤锌形态及有效性关系,为优化旱地小麦锌营养强化技术提供科学依据。【方法】基于2017年在黄土高原旱地石灰性土壤上开始的定位试验,于2021—2022和2022—2023年两个小麦生长季取样,研究锌肥用量对土壤有效锌及锌形态、小麦花前花后锌吸收转移及籽粒锌含量的影响。【结果】施用锌肥对小麦产量无显著影响,但两季小麦籽粒锌含量分别提高44.7%和38.2%,施锌25.6 kg/hm^(2)时,籽粒锌含量最高达33.6 mg/kg,花前锌吸收量分别提高38.8%~83.7%和13.4%~49.0%,花后锌转移量分别提高36.0%~73.9%和13.0%~39.6%;施锌对小麦花后锌吸收量的影响因年份而异。表层0—20和20—40 cm土壤有效锌含量分别提高11.6和11.3倍,最高分别达9.20和3.57 mg/kg,深层40—60、60—80和80—100 cm土壤有效锌含量分别提高4.4、1.8和1.9倍,最高分别达0.54、0.28和0.29 mg/kg。施用锌肥显著提高了土壤各形态锌含量,0—20和20—40 cm土层水溶态锌分别提高54.5%和75.0%,达0.17和0.14 mg/kg;松结有机态锌分别提高214.9%和90.8%,达5.70和3.11 mg/kg;碳酸盐结合态锌分别提高1178.0%和551.7%,达5.24和1.89 mg/kg;氧化锰结合态锌分别提高345.9%和183.9%,达15.52和9.37 mg/kg;紧结有机态锌分别提高91.5%和34.4%,达1.13和0.86 mg/kg;残渣态锌分别提高23.7%和24.3%,达56.57和56.80 mg/kg。【结论】施锌显著提高了土壤松结有机态、碳酸盐结合态和氧化锰结合态锌含量,并通过其向水溶态锌转化,维持了施锌后表层土壤有效锌提升和施入土壤的肥料锌的有效性,促进了小麦花前锌吸收,实现了花后地上部锌向籽粒的转移及籽粒锌含量提升,但干旱缺水影响了旱地小麦花后锌吸收,抑制了施锌后籽粒锌含量进一步提升。

不同锌源叶面喷施对冬小麦和夏玉米产量及籽粒营养品质的影响

为探明不同锌源叶面肥喷施对小麦和玉米产量、籽粒矿质元素含量及锌、铁生物有效性的影响,对冬小麦-夏玉米轮作体系开展不同叶面肥喷施试验。小麦季设置去离子水(CK1)、尿素(CK2)、尿素+纳米氧化锌(U+ZnO)、尿素+壳聚糖纳米锌(U+ZnCNP)、尿素+普通七水硫酸锌(U+Zn)5种叶面肥处理;玉米季增加尿素与锌铁硒多元混合喷施处理(U+Zn/Fe/Se)。结果表明:各叶面肥喷施处理对小麦和玉米籽粒产量均无显著影响,但对籽粒微量元素含量有显著影响。不同锌源与尿素混合叶面肥对小麦籽粒锌含量强化效果由弱到强依次为U+ZnCNP<U+ZnO<U+Zn。与CK2处理相比,处理U+Zn使小麦籽粒锌含量显著提高77.7%(从22.80 mg·kg^(-1)增加至40.52 mg·kg^(-1))、籽粒植酸与锌(PA/Zn)摩尔比显著下降42.1%,使籽粒锌生物有效性(TAZ)显著提高74.5%。对于玉米,与CK2处理相比,处理U+Zn/Fe/Se使籽粒锌含量提高32.3%(从14.93 mg·kg^(-1)增加至19.60 mg·kg^(-1))、硒含量显著提高12.7倍(从17.66μg·kg^(-1)增加至242.04μg·kg^(-1))、籽粒PA/Zn摩尔比显著下降27.0%,使籽粒TAZ显著提高36.9%,使整个植株或玉米秸秆磷与锌(P/Zn)和磷与铁(P/Fe)摩尔比降低。研究表明,叶面喷施普通七水硫酸锌是提高小麦、玉米籽粒锌含量和生物有效性的最佳形式,其强化小麦籽粒锌效果优于玉米。叶面喷施尿素与锌铁硒混合溶液可同时提高玉米籽粒锌、硒含量及锌、铁生物有效性(籽粒、全株、秸秆),是解决人体或动物微量元素营养缺乏的有效农艺强化措施。

品种和养分管理影响冬小麦籽粒锌营养

【目的】小麦籽粒中的锌含量对人类锌营养具有重要影响,研究品种特性、磷肥和丛枝菌根真菌(Arbuscular mycorrhizal fungal,AMF)对小麦籽粒锌含量的影响,为通过选择基因型育种和绿色养分管理最大化小麦锌营养提供理论依据。【方法】开展盆栽试验,供试小麦品种包括育成年代为1940s的蚂蚱麦(MZ)、1950s的碧蚂1号(BM)、1960s的丰产3号(FC)和2010s的长旱58号(CH),每个品种设置两个磷肥处理:施磷200 mg/kg(HP)和不施磷(LP);两个接菌处理:接种60 g Rhizophagus intraradices菌剂(A)和未接种(CK),每个品种均包括4个处理。在小麦开花期和成熟期,测定各部位锌含量和植株生物量、产量,分析菌根侵染率,计算菌根生长以及与菌根生长相关联的磷、锌吸收响应值(MGR、MPR、MZnR),以偏最小二乘路径模型分析锌吸收相关指标对籽粒锌含量的效应。【结果】冬小麦不同品种间籽粒产量存在显著差异,随品种的更替籽粒产量显著增加,而籽粒锌浓度随品种的更替呈降低趋势。HP-CK处理冬小麦籽粒产量较LP-CK处理显著增加36.73%~42.16%,籽粒锌浓度显著降低11.57%~27.07%,FC、CH的籽粒锌累积量分别显著增加25.75%、14.44%。LP�A处理下4个冬小麦品种的根系菌根侵染率存在显著差异;施磷显著降低了冬小麦菌根侵染率(13.04%~23.63%)且导致品种间菌根侵染率无显著差异。与LP-CK处理相比,LP-A处理冬小麦籽粒锌浓度增加6.78%~9.37%,累积量显著提高23.75%~29.79%;HP-A处理仅CH的籽粒锌累积量较HP-CK处理显著提高。磷肥施用显著降低了4个冬小麦品种的MPR值(99.29%~140.76%),BM、FC和CH的MGR值(68.22%~71.77%)和MZnR值(56.47%~67.18%)。偏最小二乘路径分析结果显示,品种对籽粒锌浓度变化影响最大(−0.656),其次是磷肥(−0.557)、产量(−0.456)和AMF(0.191)。现代品种CH始终表现出较低的籽粒锌浓度和更高的产量及籽粒锌累积量。【结论】品种的产量潜力和养分管理是影响籽粒锌浓度最重要的因素。相比于育成年代较早的品种,当代品种小麦产量潜力高,对施肥(磷肥)和接种AMF的反应也高于育成年代较早的品种,因而进一步加剧了锌含量的稀释效应。因此,当代小麦品种需特别注意补充锌肥,以缓解稀释效应带来的籽粒低锌营养。

夏玉米施用含锌尿素效应及对后茬小麦的影响

为明确新型肥料含锌尿素在夏玉米上的施用效果及其在冬小麦上的后效,采用田间试验,研究了施用含锌尿素、普通尿素、普通尿素+土施锌肥、普通尿素+喷施锌肥下夏玉米产量、养分吸收积累、土壤养分含量变化及其后效对冬小麦产量的影响。结果表明,普通尿素+喷施锌肥夏玉米产量较高,较不施氮显著增产17.5%,含锌尿素较不施氮显著增产16.7%,较普通尿素显著提高5.6%,与传统施锌无显著差异;含锌尿素地上部氮、锌素积累量较普通尿素分别显著提高9.0%、47.8%;夏玉米收获后含锌尿素处理土壤有效锌含量为1.83 mg·kg^(-1),较普通尿素处理提高88.6%;普通尿素+土施锌肥后茬冬小麦产量较高,较普通尿素显著增产11.9%,施用含锌尿素冬小麦产量较普通尿素提高4.7%,轮作周年产量提高5.2%;夏玉米利润和周年轮作利润分别提高826.2和1490.4元·hm^(-2)。含锌尿素较普通尿素提高了土壤有效锌含量,对后茬冬小麦、周年产量也有一定增产增收效果,夏玉米产量、干物质积累和氮肥利用效率等与传统施锌无显著差异。含锌尿素投入成本较传统施锌(氮肥和锌肥)降低26.1%,含锌尿素较普通尿素提高了产量和效益,具有在夏玉米-冬小麦轮作体系中推广应用的潜力。

小麦富锌育种的发展现状及研究趋势

本文总结分析了农田土壤锌含量分布现状、锌对小麦籽粒营养品质的影响、小麦对锌的吸收积累特性以及小麦籽粒锌营养强化途径等。土壤中锌含量的分布特征与地形地貌、地质构造和生态环境等密切相关,部分小麦主产区的土壤中锌含量较低。锌是一种重要的微量元素,对小麦籽粒淀粉和蛋白质含量均有影响,一般被植物根系吸收后,在根部压力或蒸腾作用下被输送到地上部,或者被横向输送到韧皮部,由韧皮部进行向上或向下的运输,再被运输到各组织和器官中。小麦锌强化途径包括遗传改良育种、农艺改良和生物技术应用等。研究结果为小麦富锌育种提供了一些新的思路。

喷施锌、钾、锰对镉胁迫下小麦生长的影响

为了缓解镉毒害,促进小麦生长,采用盆栽试验方式,研究了叶面喷施锌、钾、锰元素对镉胁迫下小麦生长的影响。结果表明:与空白对照相比,叶面喷施锌、钾、锰元素可使小麦株高分别提高10.6%、4.9%、8.0%,产量分别提高18.6%、12.1%、15.8%,千粒重分别提高8.0%、6.0%、6.6%,籽粒镉含量分别降低20.0%、18.0%、18.6%。说明叶面喷施一定浓度的锌、钾、锰元素,能够促进小麦生长,降低重金属镉的含量,提升小麦品质。

喷锌方式对冬小麦籽粒锌含量和锌利用率的影响

为探究喷锌方式对冬小麦籽粒锌含量和锌利用率的影响,采用人工(M1)和无人机(M2)两种喷施方式,设置5个锌肥施用水平(M1T0~M1T4处理锌肥浓度分别为0、0.4%、0.8%、1.2%、1.6%;M2T0~M2T4处理锌肥浓度分别为0、2.5%、5%、7.5%、10%)和3个锌氮磷肥配施的处理(M1T5:0.4%ZnSO_(4)·7H_(2)O+0.2%K_(2)HPO_(4);M1T6:0.4%ZnSO_(4)·7H_(2)O+2%尿素;M1T7:0.4%ZnSO_(4)·7H_(2)O+0.2%K_(2)HPO_(4)+2%尿素;M2T5:2.5%ZnSO_(4)·7H_(2)O+1.25%K_(2)HPO_(4);M2T6:2.5%ZnSO_(4)·7H_(2)O+12.5%尿素;M2T7:2.5%ZnSO_(4)·7H_(2)O+1.25%K_(2)HPO_(4)+12.5%尿素),人工和无人机单次喷施药液量分别为375和60 L·hm-2,通过田间试验比较分析了不同处理下冬小麦籽粒锌含量、锌携出量、光合速率、产量等性状的差异。结果表明,同一喷锌量下,人工喷施时冬小麦籽粒锌含量、锌携出量显著高于无人机喷施处理;同一喷施方式下,随着锌肥浓度的提高,籽粒锌含量和锌携出量均呈上升趋势,但无人机喷锌浓度高至10%时对籽粒锌携出量的提升作用反而减弱,旗叶净光合速率、穗粒数、籽粒收获指数和产量也显著降低。与单一施锌相比,人工和无人机锌氮配施均显著提高籽粒锌携出量和锌利用率,且M2T6处理的籽粒产量较M2T1处理显著增加,增幅22.68%。以上结果说明,相同喷锌量下,人工喷施对籽粒锌元素的强化效果优于无人机,但是采用无人机喷施时,将2.5%浓度的硫酸锌溶液与12.5%的尿素溶液配合施用,可实现籽粒产量和锌含量的同步提高。

小麦C_(2)H_(2)型锌指蛋白基因TaZFP38的克隆与功能研究

小麦是全球重要的作物,提供近55%的碳水化合物来养育世界三分之一以上的人口,增强小麦抵抗非生物胁迫的能力对于提高粮食的可持续生产及全球粮食安全至关重要。本研究通过克隆得到小麦C_(2)H_(2)型锌指蛋白基因TaZFP38,其编码区全长411 bp,共编码136个氨基酸。生物信息学分析表明,TaZFP38是亲水性蛋白质,无跨膜结构域和信号肽,在脱落酸(abscisic acid,ABA)、茉莉酸甲酯(methyl jasmonate,MeJA)和光等参与的多种非生物胁迫响应中可能发挥重要作用。烟草叶片和拟南芥原生质体中的瞬时表达显示,TaZFP38定位在细胞核。进一步对野生型和过表达株系在不同浓度NaCl、甘露醇、ABA、MeJA以及黑暗处理下的萌发率进行统计分析,结果显示,TaZFP38在干旱、盐、ABA以及黑暗处理下负调控拟南芥种子的萌发,而在MeJA处理下对拟南芥的种子萌发起着正调控作用。该研究为进一步解析C_(2)H_(2)型锌指蛋白的功能提供了基础,也为创造小麦抗逆新品系提供了优良的候选基因。