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.     

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.     

碳氮供给对小麦离体穗培养粒重、微量元素及蛋白质含量的影响

为了解碳氮供给与小麦粒重、Fe、Zn、Mn、Cu等微量元素以及蛋白质含量的关系,在离体穗培养条件下研究了灌浆初期和灌浆中期不同浓度C(蔗糖)、N(硝酸铵)供给对小麦粒重、微量元素(Fe、Zn、Mn、Cu)和蛋白质含量的影响.结果表明,随着培养基糖浓度的增大,粒重和Fe、Mn含量都表现为先升高后降低的趋势,在4%糖浓度时,均达到最高值;籽粒Zn、Cu和蛋白质含量表现为随糖浓度增大而持续降低.随着培养基N浓度的增加,粒重和Fe、Zn、Mn、Cu含量多表现为先升高后降低的趋势,且多在N浓度为0.07%时达到最高值,尤以灌浆中期开始的培养表现明显;籽粒蛋白质含量表现为随N浓度增大而持续增加.由此可见,外源C、N供给对粒重、微量元素和蛋白质含量有明显的调控效应.一定的糖供给可同时提高粒重和Fe、Mn含量,一定的N供给可同时提高粒重及微量元素和蛋白质含量.     

小麦籽粒矿质元素的基因型差异及对锌强化的响应

为了分析锌强化对不同小麦品种籽粒矿质元素含量的影响,以40个不同小麦品种(系)为材料,在扬花期叶面喷施0.5%的Zn肥,用原子吸收光谱法测定Zn处理与不处理(对照)下不同小麦品种籽粒中6种矿质元素(Zn、Fe、Ca、Mg、Cu、Mn)的含量,并分析这些元素对Zn强化的响应。结果表明,Zn处理后各品种籽粒中Zn含量均比对照有极显著上升,但上升幅度因品种而异。籽粒中Fe、Ca、Mg、Cu、Mn含量对Zn强化的响应因元素种类和品种而异,就品种平均值而言,Mn含量在Zn处理和对照间有极显著差异,Fe、Mg和Cu含量在处理与对照间无显著差异。大部分品种Zn处理后籽粒Ca含量有所下降,Mn则有所增加。对施Zn和对照间被测矿质元素的变幅进行主成分分析,前三个主成分(PC1、PC2、PC3)累积贡献率为0.76,基于前三个主成分对40个品种(系)进行类平均法的聚类分析,将40个品种分为3类:第1类包含有8个品种,Zn处理后籽粒中Ca、Mg、Cu、Fe含量总体呈现降低趋势,而Mn、Zn含量呈增高趋势;第2类包含23个品种,Zn处理后籽粒Ca、Cu含量总体有一定的降低,其余4种元素含量则有一定幅度的提高;第3类共有9个品种,施Zn后Fe含量总体有一定幅度的降低,其余5种元素含量则有一定幅度的增加。来自第2类和第3类中的12个品种在Zn处理后所测定的全部6种元素或者其中大部分元素的含量提高,适宜进行Zn强化,而其余品种Zn强化后部分或全部元素(Zn除外)与对照相比有所下降,不宜作为Zn营养强化的载体品种。     

锌铁微肥对冬小麦籽粒产量及其微量元素含量的影响

为了明确锌铁微肥对冬小麦籽粒产量及其微量元素含量的影响,在西北农林科技大学斗口试验站以西农805为试验材料进行田间试验,采用二因素裂区设计,3种锌铁肥施肥量为主区,4种锌铁肥施肥比例为副区。结果表明,在施肥量15.0kg·hm~(-2)、施肥比例4Zn∶1Fe下,小麦的产量及成穗数最高,产量提高了19.6%,穗粒数显著增加;锌铁微肥的配施有利于籽粒对Zn的累积,提高籽粒中锌含量,在施肥量45.0kg·hm~(-2)、施肥比例1Zn∶4Fe下达到最大含量,较对照提高43.8%,但铁含量低于对照。获得最高产量的锌铁微肥施用量低于籽粒最高锌含量时的锌铁微肥施用量。     

小麦籽粒灌浆期铁、锌、锰、铜积累动态的研究

为了解小麦籽粒灌浆期Fe、Zn、Mn、Cu四种微量矿质营养元素的积累规律,以黄淮麦区的小麦品种长5864、郑麦366、济麦20、新麦18为试验材料,选取同一天抽穗及开花的植株进行标记,于花后10～35 d每5 d取各品种籽粒用原子吸收分光光度计法测定了籽粒中Fe、Zn、Mn、Cu的含量,分析其含量和积累量的动态变化.结果表明,四种矿质元素在小麦籽粒中的含量和积累量均表现为Fe＞Zn＞Mn＞Cu.随籽粒灌浆的进行,各元素的含量呈下降趋势.籽粒Fe、Zn含量在花后10～30 d下降,其中花后10～20 d下降迅速,花后20～30 d下降平缓,花后30～35 d含量有所增加;籽粒Mn含量在花后10～35 d持续下降,其中花后10～25 d下降迅速,花后25～35 d下降缓慢;籽粒Cu含量在花后10～20 d下降迅速,花后20～30 d稳中略升,花后30～35 d含量下降.灌浆期籽粒各元素的积累量呈递增趋势,其日积累量在灌浆初期较高.籽粒Fe日积累量最高值出现在花后30～35 d,Zn、Mn、Cu日积累量最高值出现在花后10～15 d.在供试的四个品种中,长5864和郑麦366籽粒Fe、Cu的积累量较高,新麦18籽粒Mn、Zn的积累量较高.     

椰子中果皮4种微量元素含量动态规律的研究

对椰子果的中果皮Fe、Cu等4种微量元素的动态变化规律进行研究,并对不同果龄及不同品种间的微量元素含量进行比较和相关性分析。结果表明,椰子果在发育阶段,中果皮Mn、Cu、Zn的含量均呈降低趋势,且与果串发育程度呈显著正相关;所测4种微量元素中Fe含量最高,Cu含量最低。本地高种椰子的中果皮Mn、Cu、Zn含量间均呈极显著的正相关;小黄椰子的中果皮Fe、Mn、Cu、Zn含量间均呈极显著正相关。相同果龄椰子果的中果皮Mn和Zn的含量在2个品种间没有显著差异。     

氮肥用量对苏中冬小麦地上部主要矿质元素含量的影响

为了明确施氮量对苏中地区冬小麦主要矿质元素含量的影响,以扬麦11和扬麦13为材料,在江苏丹阳设置3个氮素水平(0、150、300kg.hm-2),研究不同施氮量对冬小麦籽粒、茎鞘和叶片中Fe、Zn、Mn、Cu、Ca、Mg和P等矿质元素含量的影响。结果表明,增施氮肥能显著提高冬小麦籽粒、茎鞘、叶片、面粉和麸皮中的Fe、Zn、Mn、Cu和Ca含量,但P含量明显下降。与对照(N0)相比,施氮量达300kg.hm-2时,扬麦11籽粒中的Fe、Zn、Mn、Cu和Ca含量分别增加了11.74%、32.20%、31.78%、66.87%和53.75%,P含量降低23.06%,茎鞘中Zn、Cu和Ca含量增加106.34%、136.97%和51.15%,P含量降低46.46%;扬麦13籽粒中Zn、Cu和Ca含量分别比对照(N0)增加33.03%、59.67%和56.63%,Mg和P含量分别降低14.10%和25.41%,叶片中Mn、Cu、Ca和Mg分别增加174.54%、27.15%、41.66%和29.95%。随着氮肥用量增加,籽粒中Mg含量呈下降趋势,但茎鞘和叶片中Mg含量呈递增趋势。籽粒、茎鞘和叶片中不同矿质元素含量对氮肥的响应存在品种间差异。在本试验条件下,适量施氮可以提高冬小麦籽粒中微量元素的含量。但是,氮肥用量过高可能降低籽粒中P和Mg的含量,不利于籽粒矿质营养品质的提高。     

拔节期追氮对小麦植株地上部Zn吸收和积累的影响

为明确拔节期追氮对小麦植株地上部Zn吸收积累的影响,于2011-2012年以周麦18和济麦22为材料,研究了拔节期不同追氮量处理下,小麦植株开花期和成熟期叶片、茎鞘、穗部、籽粒的Zn含量,分析了各部位Zn的积累量.结果表明,周麦18植株地上部Zn含量和积累量高于济麦22;从空间分布来看,植株地上各部位Zn含量和积累量均随空间位置下移而降低;随拔节期追氮量的增加,两个小麦品种植株地上部Zn积累量在开花期呈先升后降趋势,成熟期则规律不明显,说明拔节期追氮能够调控小麦花后地上各部位Zn的积累和转运.小麦籽粒Zn含量与拔节期追氮量之间的关系可用二次曲线函数进行模拟.小麦植株Zn积累量对氮肥的响应存在品种间差异,周麦18在N3(底施纯氮120 kg·hm-2,追氮100 kg· hm-2)处理下植株Zn积累量和籽粒Zn含量最高,济麦22在N4(底施纯氮120 kg· hm-2,追氮140 kg·hm-2)处理下植株Zn积累量和籽粒Zn含量最高.     

泰国罗勇府蔬果减产

Fe、Se、Zn等微量元素均为小麦正常生长发育的必须微量元素,在相对缺乏的条件下,补充相应元素可起到较好的增产效果。试验表明,Fe、Se、Zn均为小麦正常生长发育不可缺少的微量元素,且为砂姜黑土比较缺乏的元素,在小麦高产栽培中补施上述元素是满足小麦生长发育、进一步提高产量的重要措施。     

Variation in mineral micronutrient concentrations in grain of wheat lines of diverse origin

150 lines of bread wheat representing diverse origin and 25 lines of durum, spelt, einkorn and emmer wheat species were analysed for variation in micronutrient concentrations in grain. A subset of 26 bread wheat lines was grown at six sites or seasons to identify genetically determined differences in micronutrient concentrations. Substantial variation among the 175 lines existed in grain Fe, Zn and Se concentrations. Spelt, einkorn and emmer wheats appeared to contain higher Se concentration in grain than bread and durum wheats. Significant differences between bread wheat genotypes were found for grain Fe and Zn, but not Se concentration; the latter was influenced more by the soil supply. Grain Zn, but not Fe, concentration correlated negatively with grain yield, and there was a significant decreasing trend in grain Zn concentration with the date of variety release, suggesting that genetic improvement in yield has resulted in a dilution of Zn concentration in grain. Both grain Zn and Fe concentrations also correlated positively and significantly with grain protein content and P concentration, but the correlations with kernel size, kernel weight or bran yield were weak. The results from this study are useful for developing micronutrient biofortification strategies.     

Influence of long-term nitrogen fertilization on micronutrient density in grain of winter wheat (Triticum aestivum L.)

A long-term (1999–2007) field experiment was conducted to investigate the effects of three nitrogen (N) fertilization rates (0, 130, and 300 kg N/ha) on micronutrient density in wheat grain and its milling fractions. At maturity, grains were harvested and fractionated into flour, shorts, and bran for micronutrient and N analysis. N fertilization increased iron (Fe), zinc (Zn), and copper (Cu) density in wheat grain compared to the control. Increase of N application rate from 130 to 300 kg N/ha, however, did not further increase the three micronutrient densities in grain. Micronutrient concentrations were usually highest in the bran and lowest in the flour. High N application increased Zn and Cu densities in all three milling fractions and increased Fe concentration in shorts and bran but not in flour. N application did not affect the manganese (Mn) concentration in grain. N fertilization changed the proportions of Fe and Cu in flour and bran but did not affect the distribution of Zn. Because N fertilization increased micronutrient accumulation in wheat grain, proper management of N fertilization has the potential to enhance the nutritional quality of this important food.     

Effect of drought and elevated temperature on grain zinc and iron concentrations in CIMMYT spring wheat

Abiotic stress caused by increasing temperature and drought is a major limiting factor for wheat productivity around the world. Wheat plays an important role in feeding the world, but climate change threatens its future harvest and nutritional quality. In this study, grain iron (Fe) and zinc (Zn) concentrations of 54 wheat varieties, including CIMMYT derived historic and modern wheat varieties grown in six different environmental conditions, were analyzed. The objective of the study was to evaluate the effect of water and heat stress on the nutritional value of wheat grains with a main emphasis on grain protein content, Zn and Fe concentrations. Significant effects of environment on protein content and grain micronutrients concentration were observed. The protein and Zn concentrations increased in the water and heat stressed environments, whereas Zn and Fe yield per unit area was higher in non-stress conditions. The results suggest that genetic gains in the yield potential of CIMMYT derived wheat varieties have tended to reduce grain Zn, in some instances; however, environmental variability might influence the extent to which this effect manifests itself.     

Biofortification strategies to increase grain zinc and iron concentrations in wheat

Micronutrient deficiencies, especially those arising from zinc (Zn) and iron (Fe), pose serious human health problems for more than 2 billion people worldwide. Wheat is a major source of dietary energy and protein for the world's growing population, and its potential to assist in reducing micronutrient-related malnutrition can be enhanced via integration of agronomic fertilization practices and delivery of genetically-manipulated, micronutrient rich wheat varieties. Targeted breeding for these biofortified varieties was initiated by exploiting available genetic diversity for Zn and Fe from wild relatives of cultivated wheat and synthetic hexaploid progenitors. The proof-of-concept results from the performance of competitive biofortified wheat lines showed good adaptation in target environments without compromising essential core agronomic traits. Agronomic biofortification through fertilizer approaches could complement the existing breeding approach; for instance, foliar application of Zn fertilizer can increase grain Zn above the breeding target set by nutritionists. This review synthesizes the progress made in genetic and agronomic biofortification strategies for Zn and Fe enrichment of wheat.     

Improved nitrogen status enhances zinc and iron concentrations both in the whole grain and the endosperm fraction of wheat

This study was conducted to assess the role of increasing N supply in enrichment of whole grain and grain fractions, particularly the endosperm, with Zn and Fe in wheat. The endosperm is the most widely consumed part of wheat grain in many countries. Plants were grown in the greenhouse with different soil applications of N and Zn and with or without foliar Zn spray. Whole grain and grain fractions were analyzed for N, P, Zn and Fe. Increased N supply significantly enhanced the Zn and Fe concentrations in all grain fractions. In the case of high Zn supply, increasing N application enhanced the whole grain Zn concentration by up to 50% and the endosperm Zn by over 80%. Depending on foliar Zn supply, high N elevated the endosperm Fe concentration up to 100%. High N also generally decreased the P/Zn and P/Fe molar ratios in whole grain and endosperm. The results demonstrate that improved N nutrition, especially when combined with foliar Zn treatment, is effective in increasing Zn and Fe of the whole grain and particularly the endosperm fraction, at least in the greenhouse, and might be a promising strategy for tackling micronutrient deficiencies in countries where white flour is extensively consumed.     

叶面喷施微肥对冬小麦产量和品质的影响

为给小麦高产优质栽培中微肥施用提供参考,以冬小麦品种石新828为材料,研究了叶面喷施锌、铁、硒3种微肥对小麦产量、籽粒锌、铁、硒和蛋白质含量的影响。结果表明,3种微肥中只有喷硒增产作用显著(P<0.05),但喷锌、铁、硒分别显著增加了千粒重、穗数和穗粒数。3种微肥均能明显提高籽粒中相应的微量元素含量,但对籽粒蛋白质含量影响均不显著。     

Genetic diversity for grain nutrients contents in a core collection of finger millet (Eleusine coracana (L.) Gaertn.) germplasm

Finger millet is a promising source of micronutrients and protein besides energy and can contribute to the alleviation of iron (Fe), zinc (Zn) and protein malnutrition affecting women and preschool children in African and south-east Asian countries. The most cost effective approach for mitigating micronutrient and protein malnutrition is to introduce staple crop cultivars selected and/or bred for Fe, Zn and protein dense grain. Breeding finger millet for enhanced grain nutrients is still in its infancy. Analysis, detection and exploitation of the existing variability among the germplasm accessions are the initial steps in breeding micronutrient and protein-dense finger millet cultivars. Evaluation of finger millet core collection for grain nutrients and agronomic traits revealed a substantial genetic variability for grain Fe, Zn, calcium (Ca) and protein contents. The accessions rich in nutrient contents were identified and their agronomic diversity assessed. The accessions rich in Zn content have significantly higher grain yield potential than those rich in Fe and protein content. Grain nutrient-specific accessions and those contrasting for nutrient contents were identified for use in the strategic research and cultivar development in finger millet.     

Localisation of iron in wheat grain using high resolution secondary ion mass spectrometry

Insufficient iron (Fe) is one of the most prevalent micronutrient deficiencies in humans, with billions of people affected. Cereal grains are an important source of Fe for humans but the bioavailability of Fe in cereals is generally low. Information regarding the cellular and sub-cellular localisation of Fe in wheat grain will aid optimising nutrient delivery for human health. In this study high resolution secondary ion mass spectrometry (NanoSIMS) was used to map the distribution of Fe in the aleurone layer and in the endosperm of immature wheat grain. Iron was shown to be localised strongly in the phytin globoids in the aleurone cells and to a lesser extent in the cytoplasm around the starch granules in the endosperm.