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1.
Grain zinc (Zn) and iron (Fe) concentrations and their responses to foliar application of micronutrients in 28 Chinese wheat landraces and 63 cultivars were investigated in a two-year field experiment.  The average grain Zn and Fe concentrations were 41.8 mg kg–1 (29.0−63.3 mg kg–1) and 39.7 mg kg–1 (27.9−67.0 mg kg–1), respectively.  Compared with cultivars, landraces had greater grain Zn (11.0%) and Fe (4.8%) concentrations but lower harvest index (HI), grain weight per spike (GWS), grain number per spike (GNS) and thousand grain weight (TGW).  Both Zn and Fe concentrations were negatively and significantly correlated with HI, GWS, and GNS, while showed a poor association with TGW, suggesting that lower HI, GWS, and GNS, but not TGW, accounted for higher Zn and Fe concentrations for landraces than for cultivars.  Grain Zn concentrations of both cultivars and landraces significantly increased after foliar Zn spray and the increase was two-fold greater for landraces (12.6 mg kg–1) than for cultivars (6.4 mg kg–1).  Foliar Fe spray increased grain Fe concentrations of landraces (3.4 mg kg–1) and cultivars (1.2 mg kg–1), but these increases were not statistically significant.  This study showed that Chinese wheat landraces had higher grain Zn and Fe concentrations than cultivars, and greater increases occurred in grain Zn concentration than in grain Fe concentration in response to fertilization, suggesting that Chinese wheat landraces could serve as a potential genetic source for enhancing grain mineral levels in modern wheat cultivars.  相似文献   

2.
Natural iron isotope variations in human blood   总被引：1，自引：0，他引：1  
Isotopic analysis of human blood and liver and muscle tissue indicates that each individual bears a long-term iron (Fe) isotope signature in the blood. Blood and tissue differ slightly in isotopic composition and are depleted by up to 2.6 per mil in 56Fe relative to 54Fe when compared to dietary Fe. The 56Fe/54Fe isotope ratio in the blood of males is, on average, lower by 0.3 per mil than that of females. These results suggest that Fe isotope effects in the blood reflect differences in intestinal Fe absorption between individuals and genotypes.  相似文献   

3.
Archean rocks may provide a record of early Earth environments. However, such rocks have often been metamorphosed by high pressure and temperature, which can overprint the signatures of their original formation. Here, we show that the early Archean banded rocks from Isua, Akilia, and Innersuartuut, Greenland, are enriched in heavy iron isotopes by 0.1 to 0.5 per mil per atomic mass unit relative to igneous rocks worldwide. The observed enrichments are compatible with the transport, oxidation, and subsequent precipitation of ferrous iron emanating from hydrothermal vents and thus suggest that the original rocks were banded iron formations (BIFs). These variations therefore support a sedimentary origin for the Akilia banded rocks, which represent one of the oldest known occurrences of water-laid deposits on Earth.  相似文献   

4.
The origin of Cu/Au ratios in porphyry-type ore deposits   总被引：3，自引：0，他引：3  
Microanalysis of major and trace elements in sulfide and silicate melt inclusions by laser-ablation inductively coupled plasma mass spectrometry indicates a direct link between a magmatic sulfide liquid and the composition of porphyry-type ore deposits. Copper (Cu), gold (Au), and iron (Fe) are first concentrated in a sulfide melt during magmatic evolution and then released to an ore-forming hydrothermal fluid exsolved late in the history of a magma chamber. The composition of sulfide liquids depends on the initial composition and source of the magma, but it also changes during the evolution of the magma in the crust. Magmatic sulfide melts may exert the dominant direct control on the economic metal ratios of porphyry-type ore deposits.  相似文献   

5.
微量元素对宁夏粳稻愈伤组织绿苗分化的影响   总被引：1，自引：0，他引：1  
通过调整MS培养基中碘、硼、锰、锌、钼、铜、钴以及铁8种离子的有无及浓度,研究了微量元素对宁夏粳稻愈伤组织分化成苗的影响.结果表明:缺少碘、硼、锰、锌、钴的培养基对粳稻愈伤组织分化成苗影响不大,缺少钼的培养基对愈伤组织分化成苗有一定的影响.而缺少铜和铁的培养基则对宁夏粳稻愈伤组织分化成苗产生很大影响.在培养基中添加不同浓度的铁和铜元素的试验表明在铁盐浓度为0.05 mmol·L-1,铜离子浓度为1.0×10-4 mmol·L-1时,分化成苗效果最好,而此试验中设置的其他铁离子和铜离子浓度均对粳稻分化和生长均产生不利影响.  相似文献   

6.
土壤氧化铁的形态在浙江红壤和黄壤分类中的意义   总被引：1，自引：0，他引：1  
研究结果表明,红壤和黄壤之间铁矿物形态有明显的差异,黄壤的铁游离度、晶胶比以及赤铁矿系数均小于红壤;而铁活化度、络合态铁占游离态铁的百分比及氧化铁的水合系数都是黄壤高于红壤。黄壤以不含或仅含极少量的赤铁矿而区别于红壤。针铁矿普遍存在于所研究的各土壤中;部分土样还含少量纤铁矿。测定数据的统计分析表明,铁游离度、铁活化度以及赤铁矿系数等可以用来划分红壤、黄红壤和黄壤亚类。  相似文献   

7.
锌(Zn)是动植物和人体必需的微量元素,能预防肺炎等疾病和提高人体免疫功能。小麦作为中国主要粮食作物,为满足人体对锌的营养需求,提高小麦籽粒锌含量十分必要。为给优质富锌小麦生产提供理论依据和技术支撑,通过在田间条件下进行土壤和叶面施锌试验,研究其对小麦农艺性状和籽粒产量的影响,尤其是对籽粒锌浓度的生物强化效果,以及对籽粒中其他2种有益微量元素（铁和硒）的影响规律。结果表明：土施锌肥使小麦穗数从447.0万穗/hm2增加到511.5万穗/hm2,增幅14.4%。土壤和叶面施Zn使得小麦籽粒产量从5419.5~6250.5 kg/hm2增加到6372.0~6811.5 kg/hm2,增幅5.2%~17.6%,对籽粒铁和硒浓度均无显著影响,有效提升籽粒Zn浓度,从34.0~39.6 mg/kg提高到44.6~46.6 mg/kg,增幅17.7%~32.9%,达到世界卫生组织等机构和科学家所推荐的生物强化目标值(40~50 mg/kg)。因此,土壤和叶面施Zn提高小麦产量的同时,可以提升籽粒锌营养品质,是实现小麦提质增效的有效途径,建议大面积推广应用。  相似文献   

8.
The effects of a large igneous province on the concentration of atmospheric carbon dioxide (PCO?) are mostly unknown. In this study, we estimate PCO? from stable isotopic values of pedogenic carbonates interbedded with volcanics of the Central Atlantic Magmatic Province (CAMP) in the Newark Basin, eastern North America. We find pre-CAMP PCO? values of ~2000 parts per million (ppm), increasing to ~4400 ppm immediately after the first volcanic unit, followed by a steady decrease toward pre-eruptive levels over the subsequent 300 thousand years, a pattern that is repeated after the second and third flow units. We interpret each PCO? increase as a direct response to magmatic activity (primary outgassing or contact metamorphism). The systematic decreases in PCO? after each magmatic episode probably reflect consumption of atmospheric CO? by weathering of silicates, stimulated by fresh CAMP volcanics.  相似文献   

9.
Pyrus pashia Buch-Ham, a wild specie was used to investigate the physiological effects of irondeficiency in culture solution. The result showed that Chla, Chlb, total chlorophyll content and photosynthesisrate(Ph) decreased sharply, and the decrease of Pn was prior to that of Chl content under the iron deficiency.The iron deficiency symptoms were visible when the iron concentration in culture medium was less than 25μmol L-1. Peroxidase(POD) and catalase(CAT) activity in iron-deficient leaves declined significantly, andPOD was more sensitive than CAT to Fe deficiency. However, the positive correlation between CAT activityand Chl content was more significant than that between POD activity and Chi content. The content of nutrientelements in Fe-deficient leaves, which changed irregularly, were higher than that in normal leaves. There werea most significant positive correlation between active Fe and Chi content, and between active Fe and Pn respec-tively. Therefore, active Fe could be useful physiological predicting index for diagnosis.  相似文献   

10.
选375日龄健康的罗曼蛋鸡387羽,随机分为3组,每组设3个重复,每一重复43羽.对照组基础日粮中添加80 mg/kg铁(硫酸亚铁),两试验组分别添加80 mg/kg铁(甘氨酸铁)、80 mg/kg铁(纳米硫酸亚铁).试验为期10周,研究日粮中不同铁源对罗曼蛋鸡产蛋性能和蛋品质的影响.结果表明,苷氨酸铁与纳米硫酸亚铁组与对照组的生产性能无显著差异(P＞0.05),但均有提高;并具有提高蛋中铁含量的作用,使蛋黄中铁的沉积量分别提高了6.10%(P＞0.05)、43.95%(P＜0.05),蛋白中铁的沉积量分别提高了41.90%(P＜0.05)、72.01%(P＜0.01).  相似文献   

11.
Iron isotope fractionation and the oxygen fugacity of the mantle   总被引：3，自引：0，他引：3  
The oxygen fugacity of the mantle exerts a fundamental influence on mantle melting, volatile speciation, and the development of the atmosphere. However, its evolution through time is poorly understood. Changes in mantle oxidation state should be reflected in the Fe3+/Fe2+ of mantle minerals, and hence in stable iron isotope fractionation. Here it is shown that there are substantial (1.7 per mil) systematic variations in the iron isotope compositions (delta57/54Fe) of mantle spinels. Spinel delta57/54Fe values correlate with relative oxygen fugacity, Fe3+/sigmaFe, and chromium number, and provide a proxy of changes in mantle oxidation state, melting, and volatile recycling.  相似文献   

12.
通过对比的方法系统研究了葛薯（赣葛5号）的栽培技术，结果表明（1）在红壤类型的土壤中，以坡腰和坡底土壤的葛薯出苗率最高，每hm^2产量达12万株左右。以水库尾土壤的葛薯产量最高，每hm^2产量达5．5万kg。以坡底土壤的葛薯出粉率最高，达23．6％。（2）挖种植沟是高产栽培的关键技术之一，以沿等高线挖种植沟栽培葛薯增产效果最好，每hm^2产量达5万kg。（3）种植密度对葛薯产量和商品合格率有很大影响，以每hm^2栽4500—6000株的产量和商品合格率最高。（4）种苗质量对成活率和葛薯产量均有显著影响，以一类苗最高，分别为：成活率100％，产量为当年每hm^2产1．8万kg。（5）移栽时间不同对葛薯成活率的影响，在江西地区应在4月中旬以前移栽，成活率在85％以上。（6）合理施肥能够提高葛薯的产量及出粉率，比没有施肥分别提高1～1．5倍及1％-2％。同时能够提高黄酮含量，施肥的含量为11．52mg／g，没有施肥的含量为6．68mg／g。  相似文献   

13.
磷素对水稻根表红棕色铁膜的影响及营养效应   总被引：2，自引：0，他引：2  
【目的】磷饥饿能明显诱导水稻根表红棕色铁膜的形成。然而,磷素是如何诱导水稻根表红棕色铁膜形成并不清楚。【方法】论文在水培条件下,对24个不同来源的传统水稻品种培养21 d后,分别进行缺磷和0.1 mmol•L-1 Fe2+处理,测定其根长、根表面积、根系干重、地上部干重及根表铁含量,从而筛选出根表铁膜含量较高的水稻品种“天优998”,并以此为材料,设置不同养分元素缺乏试验（缺氮、缺磷、缺钾及其交互等8个处理）、分根试验（两边根系同时进行正常磷处理;一边根系缺磷处理,另一边根系正常供磷处理;两边根系同时进行缺磷处理）和不同磷铁比试验（磷浓度为0.0125-0.4 mmol•L-1;铁浓度为0.1-3.2 mmol•L-1,按磷铁比为1﹕1;1﹕3;1﹕5;1﹕8处理设计了4个小试验）,测定了水稻根表铁膜浓度、根表无机磷浓度、根内无机磷浓度、根系和地上部磷、铁含量,探讨了磷素对根表红棕色铁膜形成及其营养效应。【结果】不同水稻品种根表铁膜浓度存在明显差异,24个水稻品种幼苗根表铁膜浓度范围为3.67-9.78 mg•g-1,水稻根表铁膜含量与根长、根表面积、根系干重、地上部干重呈显著的正相关。不同养分元素缺乏试验表明,水稻根表铁膜由红棕色铁膜和非红棕色铁膜组成,仅缺磷处理都能诱导水稻根表红棕色铁膜的形成,而缺氮和缺钾处理却不能。分根试验处理表明,缺磷处理根系侧并不能诱导正常供磷处理侧根系根表形成红棕色铁膜,根表红棕色铁膜形成主要受根表外源无机磷的影响,与根内无机磷无关。不同磷铁比试验表明,根表红棕色铁膜形成与根表磷铁比有关,根表DCB-Fe浓度与根系溶液中铁浓度有关;只有当磷铁比≤1﹕3时,根表才会形成明显的红棕色铁膜,随着磷铁比的降低,根表红棕色铁膜颜色加深;随着根系溶液中铁浓度的增加,根表DCB-Fe浓度逐渐增加,最大值为36.50 mg•g-1。最后进一步对磷铁比处理形成的根表红棕色铁膜水稻根系和地上部磷、铁吸收量进行测定,研究结果发现,根表红棕色铁膜的加深有利于水稻根系和地上部磷、铁的吸收。【结论】内源磷信号并不能诱导根表红棕色铁膜的形成,仅外源磷缺乏才能诱导根表红棕色铁膜的形成,根表红棕色铁膜的形成与根系周围环境中磷铁比有关,而根表DCB-Fe的形成仅与溶液中铁浓度有关。形成的根表红棕色铁膜在根系周围充当营养库的功能,有利于植物对磷、铁的吸收利用。  相似文献   

14.
The natural remanent magnetization (3.7 x 10(4) electromagnetic units per cubic centimeter) and the susceptibility per cubic centimeter (6.3 x 10(-13)) of an 18.5-gram breccia specimen were determined with instrumentation and techniques currently used in paleomagnetism. The relatively low magnetic stability of the rock in the earth's field and in alternating demagnetizing fields precludes considering it as a reliable carrier of paleomagnetism. A magnetic balance study yields an unusually high Curie temperature (750 degrees C) which is possibly diagnostic of metallic Fe containing less than 5 percent nickel. The estimated relative abundance of the iron in the sample is about 0.5 percent.  相似文献   

15.
A survey of hydrothermal activity along the superfast-spreading (approximately 150 millimeters per year) East Pacific Rise shows that hydrothermal plumes overlay approximately 60 percent of the ridge crest between 13 degrees 50' and 18 degrees 40'S, a plume abundance nearly twice that known from any other rige portion of comparable length. Plumes were most abundant where the axial cross section is inflated and an axial magma chamber is present. Plumes with high ratios of volatile ((3)He, CH(4), and H(2)S) to nonvolatile (Mn and Fe) species marked where hydrothermal circulation has been perturbed by recent magmatic activity. The high proportion of volatile-rich plumes observed implies that such episodes are more frequent here than on slower spreading ridges.  相似文献   

16.
黄叶绿制剂防治酥梨缺铁黄化症的研究   总被引：1，自引：1，他引：1  
采用休眠期强力注射黄叶绿制剂 (YL G)进行缺铁黄化症的防治试验。结果表明 ,注射 YL G制剂后黄化级平均为 0 .2级 ,比对照下降 2 .76级 ,复绿明显。处理单叶面积增加 3.5 cm2 ,比叶重增加 0 .88mg/ cm2 ,叶绿体各色素含量极显著增加 ,其中总叶绿素增加 2 .2 6倍 ,净光合速率增加 2 7.6 % ,叶内 N,P,Zn,Fe和活性 Fe极显著增加 ,K,Ca,Mg,Mn,Cu和 B等含量下降 ,但均在标准值范围内。处理使果实产量提高 34.5 % ,单果重增加18.32 % ,可溶性固形物和可溶性糖极显著增加 ,果实品质明显改善 ,花芽分化率和花芽质量也明显提高  相似文献   

17.
The composition limits of Fe(x)O are sensitive to both pressure and temperature. Earlier studies have shown that Fe(x)O becomes highly nonstoichiometric when in equilibrium with metallic iron above 10 gigapascals, which is difficult to reconcile with available thermodynamic data. Experiments with a uniaxial split-sphere apparatus demonstrate that the iron content of Fe(x)O increases continuously at high pressure in excellent agreement with quantitative models and suggest that there is a discontinuity in the elastic properties of Fe(x)O above x = 0.95. On the basis of these results, it is inferred that the Earth's present lower mantle is not in equilibrium with metallic iron.  相似文献   

18.
Oxygen isotopic composition of our solar system is believed to have resulted from mixing of two isotopically distinct nebular reservoirs, 16O-rich and (17,18)O-rich relative to Earth. The nature and composition of the (17,18)O-rich reservoir are poorly constrained. We report an in situ discovery of a chemically and isotopically unique material distributed ubiquitously in fine-grained matrix of a primitive carbonaceous chondrite Acfer 094. This material formed by oxidation of Fe,Ni-metal and sulfides by water either in the solar nebula or on a planetesimal. Oxygen isotopic composition of this material indicates that the water was highly enriched in 17O and 18O (delta(17,18)O(SMOW) = +180 per thousand per mil), providing the first evidence for an extremely (17,18)O-rich reservoir in the early solar system.  相似文献   

19.
Previous studies of anaerobic biocorrosion have suggested that microbial sulfur and phosphorus products as well as cathodic hydrogen consumption may accelerate anaerobic metal oxidation. Methanogenic bacteria, which normally use molecular hydrogen (H(2)) and carbon dioxide (CO(2)) to produce methane (CH(4)) and which are major inhabitants of most anaerobic ecosystems, use either pure elemental iron (Fe(0)) or iron in mild steel as a source of electrons in the reduction of CO(2) to CH(4). These bacteria use Fe(0) oxidation for energy generation and growth. The mechanism of Fe(0) oxidation is cathodic depolarization, in which electrons from Fe(0) and H(+) from water produce H(2), which is then released for use by the methanogens; thermodynamic calculations show that significant Fe(0) oxidation will not occur in the absence of H(2) consumption by the methanogens. The data suggest that methanogens can be significant contributors to the corrosion of iron-containing materials in anaerobic environments.  相似文献   

20.
半紧凑型春玉米的产量与叶片性状   总被引：8，自引：0，他引：8  
在华南农业大学教学试验场栽植粤顶９号玉米按４．５万株／ｈｍ＾２与６．７５万株／ｈｍ＾２种密度,结果表明低密度下穗粒性状有改善的趋势,但未达到显著程度。植株总叶龄变异极小,叶面积与干物质的增长呈指数曲线。生长期内低密度植株净化同化率后期较高。各叶长宽呈现明显的抛物线规律。  相似文献   

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