富硒肥的研究及其应用

硒是人体必需的微量元素。富硒肥的开发和应用,是提高农作物中可食部分的硒含量,进而改善人类硒营养的重要途径。综述了外源硒的种类与形式、施用硒肥对农作物硒含量及其化学形态和农作物品质的影响,旨在为富硒肥和富硒农产品的研究和开发提供依据。     

硒对农产品营养品质的影响

硒是人体必需的营养元素,作为重要物质参与机体的新陈代谢,摄入量不足会引发多种疾病,富硒农产品是膳食补充硒元素的重要来源之一。本文分析了农产品富硒的主要方式,综合阐述了硒对植物性农产品中蛋白质、脂肪、多糖、其他元素、次生代谢产物和动物性农产品营养品质的影响,为富硒农产品的生产,特别是富硒农产品营养品质的调控与提升提供理论支撑。     

我国富硒农产品与土壤标准研究

硒是人和动物生命活动必需的微量元素,缺硒可影响人体健康并导致诸多疾病。通过富硒农产品补硒是一种简单而有效的方法。本文从硒对人体的健康功效、居民硒的摄入量状况、土壤硒分布与作物硒吸收特征、富硒土壤研究现状、富硒农产品标准、富硒农产品中硒摄入量安全性评估等方面,进行了系统研究,阐述了研制富硒土壤分类标准的必要性。     

桑肠杆菌菌株的富硒特性及其喷施对玉米籽粒的硒素强化

硒是人体必需微量元素之一,对新陈代谢过程有十分重要的促进作用,通过生物强化措施可以增加人体对硒素的补充。该研究利用从植物内生菌中筛选出的一株具有将无机硒转化成生物利用率更高的有机硒的菌株IX+2 2,测定其16S r RNA基因序列,鉴定该菌株为桑肠杆菌(Enterobacter mori)。该文研究不同的硒含量、加硒时间与不同培养收集时间对菌株IX+2 2硒素转化率的影响。结果表明,培养基中硒含量越高,菌株IX+2 2胞内有机硒含量越高,硒素转化率越高,但达到某一个峰值后又开始下降;在对数生长期加硒有利于菌株IX+2 2的生长和对无机硒的转化;菌株培养24 h时收集硒素转化效果最好,继续培养菌体生长减弱。同时针对菌株对玉米籽粒富硒的强化效应做了进一步验证。该菌株对玉米籽粒富硒的强化作用表明:同等亚硒酸钠用量条件下,亚硒酸钠喷施处理后玉米籽粒中硒含量达到228.58μg/kg,而富硒微生物菌剂处理后籽粒中硒含量达到378.89μg/kg,是前者的1.66倍,富硒IX+2 2菌剂的富硒效果优于喷施亚硒酸钠溶液。该研究结果可为玉米籽粒的硒素强化提供理论支撑。     

武鸣区富硒水稻种植技术

作为我国重要的粮食作物,水稻的发展对于我国农作物产量有着重要影响。随着人们的健康意识的逐渐提高,关于水稻营养问题也越来越受到重视。硒是人体所必需的微量元素,富硒水稻是近年来快速发展的水稻品种,它不仅保留了普通水稻的全部营养物质,同时具有良好的抗癌、防癌、保护心脏以及延缓衰老等作用。因此研究富硒水稻的种植技术对于大量推广富硒水稻的种植具有重要意义。基于此,重点介绍武鸣地区富硒水稻的栽植技术,以期为武鸣地区富硒水稻的推广栽培提供一定的技术支持。     

富硒稻谷栽培技术分析

硒元素是人体必需的微量元素,食用富硒农产品是人类补充硒元素的有效方法,因此,富硒作物栽培技术不断发展。基于此,从水稻品种选择、培育壮秧、适时移栽、大田管理和科学施用硒肥等方面介绍了应用蛋氨酸硒栽培富硒稻谷的关键技术,为类似自然条件地区发展富硒稻谷生产提供参考。     

万秀区富硒水稻栽培技术及病虫害防治措施探究

现代科学研究证明,硒具有抗氧化、增强人体免疫力、有效清除人体有害垃圾、促进人体健康、延缓衰老之功效。硒是人类必需的重要元素,有机硒对40多种疾病疗效显著。目前,全球有42个国家和地区共20多亿人缺硒,中国已查明大约72%的国土缺硒。而经研究证实,当今公认的最安全、最有效、最科学的人体补硒方法是食用富硒农产品。随着人们消费水平的日益提高,消费者的消费需求逐渐倾向于注重产品的功能性,富硒产品的市场逐步扩大。基于此,介绍了富硒水稻及广西梧州市万秀区富硒水稻概况,探讨万秀区富硒水稻栽培技术及病虫害防治措施。     

充分发挥资源优势 大力发展富硒产业

硒是人和其他动物必需的微量元素,具有抗氧化抗衰老、保护和修复细胞、提高人体免疫力、解除重金属毒害、预防癌变等功能,对人类健康有着重要的作用。广西北海市拥有富硒土壤面积达20000 hm~2以上,开发富硒农产品,发展富硒产业,事关农业增效农民增收,事关人类健康幸福,意义特别重大,前景十分广阔。文章对北海市大力发展富硒产业进行了规划和展望。     

植物中硒的含量、影响因素及形态转化研究

综合近年来国内外的研究文献,从硒对植物的生理作用、植物含硒量和影响因素以及植物硒形态分布和转化等方面进行了系统分析。今后应该继续对硒在植物体内的作用进行深入分析,结合分子和基因手段以及硒同位素技术,探索培育富硒作物品种的可能性以及在生产实践中应用的价值。继续在自然土壤条件下加强富硒作物生产技术的开发,为合理利用硒资源提供可持续技术保障。     

典型富硒植物中硒形态和生物可给性研究

为了评估生物营养强化技术在富硒农产品生产中的应用效果,本文对苏州硒谷科技有限公司提供的生物营养强化所得富硒植物材料中硒的含量、形态和生物可给性进行了测定。结果表明:生物营养强化技术可有效提高植物中硒的含量,检测样品中硒的含量达到0.91～110.8 mg/kg。富硒植物中硒的形态主要以硒代氨基酸形式的有机硒为主,其中富硒谷物和大豆中硒主要存在形态为硒代蛋氨酸(SeMet,44.2%～80.4%),富硒西兰花中硒主要存在形态为SeMet(27.8%)、硒代胱氨酸(SeCys2,25.9%)和硒甲基硒代半胱氨酸(MeSeCys,37.1%),壶瓶碎米荠中硒主要存在形态为SeMet(73%)和SeCys2(23.8%)。富硒植物中硒具有较高的生物可给性,其中富硒小麦和大豆达到90%,富硒玉米和西兰花达到80%,壶瓶碎米荠为50%。生物营养强化所得富硒植物具有硒含量高、有机硒比例大和较好的生物可给性,可作为人体补充硒的重要原料。     

Determination of selenium concentration of rice in china and effect of fertilization of selenite and selenate on selenium content of rice

A method of hydride generation atomic fluorescence spectrometry was applied to the determination of the selenium concentration of regular polished rice in China and selenium-enriched polished rice obtained by foliar application of selenium-enriched fertilizer in the forms of selenite and selenate. The average selenium content of regular rice was 0.025 +/- 0.011 microg g(-)(1). On the basis of a daily dietary rice intake of 300-500 g suggested by the China Nutrition Society, the total selenium intake from regular rice was calculated to be 7.5-12.5 microg per person per day for an adult. The selenium contents of rice were significantly increased to 0.471-0.640 microg g(-)(1) by foliar application of selenium-enriched fertilizer at rate of 20 g of Se ha(-)(1) in the forms of sodium selenite and sodium selenate. The selenium content of rice by application of a fertilizer of selenate was 35.9% higher than that by a fertilizer of selenite, which showed that Se-enriched fertilizer in selenate exhibited greater efficiency in increasing Se content in rice products. The Se-enriched rice products can increase daily Se intake on average by 100-200 microg of Se per day by the consumption of 400 g of rice products if the Se level of rice products is controlled at 0.3-0.5 microg of Se g(-)(1). Because rice is a staple food in China, selenium-enriched rice obtained by bioenrichment of selenium to increase the Se content of rice could be a good selenium source for the population in selenium-deficient regions.     

新疆伊犁土壤硒资源分布及与土壤性质的关系分析

调查研究了伊犁州土壤中硒资源的分布特征,为该地区富硒农产品的开发提供理论指导。用原子荧光光度法测定了新疆伊犁州6个县158个农田土壤样品的全硒含量,并运用统计分析方法对伊犁州土壤硒资源的分布特征及与土壤理化性质的关系进行了分析。结果表明,伊犁州6个县土壤中全硒含量范围为0.14~2.75 mg·kg-1,几何均值为0.33 mg·kg-1,其中昭苏县土壤全硒含量均值最高,巩留县最低。所检测的土壤样品中有2.38%属于少硒土壤,78.57%属于足硒土壤(0.175~0.45 mg·kg-1),19.05%属于高硒土壤(0.45~3.00 mg·kg-1)。统计分析的结果表明,有机质、速效钾、碱解氮与全硒含量呈极显著正相关(P0.01),p H值与硒含量成显著负相关(P0.01)。伊犁州土壤中硒的含量水平偏高,可以优先考虑富硒农业的开发建设。     

Effect of selenium on preservation quality of green tea during autumn tea-processing season

Selenium-enriched green tea leaves were prepared by foliar applications of selenium-amended fertilizer during autumn season. The influence of selenium (Se) on preservation quality of tea during 4-month storage was determined. The results showed that the Se and vitamin C contents of green tea were significantly increased by selenium spraying during the autumn tea-producing season. The vitamin C content of Se-enriched green tea was higher and its decline was significantly slower during storage compared to normal green tea. However, there was no significant difference between the contents of chlorophyll and polyphenol of Se-enriched and regular tea. During the first 60 days, the color of green tea extract in Se-enriched green tea and normal tea showed no significant difference. However, the color of green tea extract in Se-enriched green tea was more stable compared with normal tea during the storage period. The sweetness and aroma of extracts of Se-enriched green tea were also significantly higher than that of normal tea and the bitterness of extracts of Se-enriched green tea was significantly lower compared with normal tea. These results showed that selenium application can slow the reduction of tea's major component and thus improve preservation qualities of green tea.     

植物根系与叶片吸收硒的关键过程及影响因素

硒元素具有抗癌、抗衰老、提高人体免疫力等功能,经植物吸收转化后,可以更加安全高效地被机体吸收利用。富硒植物产品是时下功能性农业的主要产品之一,经济器官富集较高的硒是该产品的核心。然而,目前市面上富硒植物产品的硒含量却参差不齐且普遍偏低。因此,系统研究植物吸收硒元素的途径、关键过程与影响因素对提高植物的富硒效率具有十分重要的意义。本文总结了植物根系和叶片吸收硒的主要过程,地理位置、土壤成分及其理化性质等因素对植物根系吸收硒的影响,以及硒源种类、浓度、叶片结构及叶龄、生育时期、助剂等因素对植物叶片吸收硒元素的影响。据此,提出未来还需要加强植物吸收硒的影响因素、调控机制,建立相对标准的试验模式和富硒产品评价体系等建议,以期尽快补足研究与生产之间差距,推动以富硒为导向的功能性农业科学健康发展。     

影响作物吸收硒的土肥因素研究进展

硒是人体的必需元素,硒缺乏会造成多种疾病。通过摄入农产品适量补充硒,能保证人体健康。对作物补充适量硒肥,是增加农产品硒含量的有效措施。作物吸收硒与土壤因素及肥料因素关系密切,判断哪个因素是影响作物吸收硒最关键的因素值得探讨。通过对文献系统调研发现,影响作物吸收硒的土肥因素中,土壤本身的硒含量及硒肥量最关键,土壤pH及有机质含量为活化土壤硒的间接因素,硒肥种类及施肥方式为配合硒肥量的补充因素。促进作物对硒的吸收要结合土壤性质、硒肥量、施肥方式等因素综合考虑,以达到富硒农产品高产高效的目的。     

硒镉伴生对富硒土壤柑橘生长及生理代谢的影响

为保障富硒柑橘的安全生产,明确富硒土壤硒镉伴生现象对柑橘生长、硒镉吸收转运和抗氧化能力的影响,采用盆栽试验,以一年生大雅柑橘为试验材料,研究添加硒代蛋氨酸(SeMet,CK,模拟富硒土壤)和添加SeMet与镉(模拟富硒土壤硒镉伴生)对富硒土壤柑橘的生长指标、硒镉含量、叶片还原型抗坏血酸-谷胱甘肽(AsA-GSH)循环效率的影响。结果表明,与CK相比,富硒土壤中,硒镉伴生增加了柑橘叶片叶绿素a+b、叶绿素a、叶绿素b和类胡萝卜素含量,但对株高、新梢长度、新梢数量以及根茎叶的干物质量影响不显著;在富硒土壤中,硒镉伴生显著增加了大雅柑橘硒含量和硒的富集系数(BCF),降低了硒的转运系数(TF);硒和镉主要分布在根系,其次是叶片和茎;在AsA-GSH循环中,硒镉伴生使过氧化氢(H₂O₂)和还原型抗坏血酸(AsA)含量显著上升,脱氢抗坏血酸(DHA)含量上升但未达到显著水平,抗坏血酸过氧化物酶(APX)、谷胱甘肽还原酶(GR)活性和脱氢抗坏血酸还原酶(DHAR)活性显著上升,而GSH和氧化型谷胱甘肽(GSSG)含量下降,AsA/(AsA+DHA)和GSH/(GSH+GSSG)比值降低,谷胱甘肽过氧化物酶(GPX)活性显著降低。本研究为阐明镉胁迫对富硒土壤柑橘的生理影响机制提供了理论依据。     

Enriched selenium and its effects on growth and biochemical composition in Lactobacillus bulgaricus

Se-enriched Lactobacillus bulgaricus (L. bulgaricus) was generated by administration of sodium selenite (0, 1, 4, 8, 16, 32, and 64 mg/L, respectively) in MRS medium and enriched selenium manifestation in L. bulgaricus was investigated using transmission electron microscopy and energy-dispersive X-ray spectrometry and alterations of essential elements and amino acids in the organism were evaluated. We demonstrate that administration of sodium selenite in the dosage of 1-16 mg/L is suitable for selenium enrichment in L. bulgaricus and can enhance nutritive value in the organism by elevating the contents of essential elements including P, Mg, Mn, Zn, Ca, and total amino acids as well as reducing selenite to insoluble elemental selenium, an electron-dense and amorphous Se (0) granule, thereby depositing it both in the cytoplasm and in the extracellular space of L. bulgaricus. Thus, Se-enriched Lactobacillus can provide a potential dietary source of nontoxic selenium and functional regulator used for food and medical industry.     

Application of isotope dilution analysis for the evaluation of extraction conditions in the determination of total selenium and selenomethionine in yeast-based nutritional supplements

Isotope dilution analysis (IDA) has been used to quantify total selenium, total solubilized selenium, and the selenomethionine (SeMet) amount in yeast and yeast-based nutritional supplements after acid microwave digestion and different enzymatic extraction procedures. For this purpose, both a (77)Se-enriched SeMet spike, previously synthesized and characterized in our laboratory, and a (77)Se(VI) spike were used. In the analysis of the nutritional supplements, the SeMet spike was added to the sample and extracted under different conditions, and the (78)Se/(77)Se and (80)Se/(77)Se isotope ratios were measured as peak area ratios after high-performance liquid chromatography (HPLC) separation and inductively coupled plasma mass spectrometry (ICP-MS) detection. The formation of SeH(+) and mass discrimination were corrected using a natural SeMet standard injected every three samples. Similarly, total solubilized selenium was measured in the extracts after enzymatic hydrolysis using the (77)Se-enriched SeMet as a spike by direct nebulization without a chromatographic separation. To establish a mass balance, total selenium was also determined by IDA-ICP-MS on the yeast tablets after microwave digestion using (77)Se(VI) as a spike. Results showed that all enzymatic procedures tested were able to solubilize total selenium quantitatively from the solid. However, the recovery for the species SeMet, the major selenium compound detected, was seriously affected by the enzymatic procedure employed and also by the matrix composition of the supplement evaluated. For the yeast sample, SeMet recovery increased from 68 to 76% by the combined use of driselase and protease. For the nutritional supplements, the two most effective procedures appeared to be protease and driselase/protease, with a SeMet recovery ranging from 49 to 63%, depending upon the supplement evaluated. In the case of in vitro gastrointestinal enzymolysis, the results obtained showed 26-37% SeMet recovery, while the rest of selenium was solubilized as other unknown compounds (probably Se-containing peptides).     

重庆市奉节县中部土壤硒富集特征及来源分析

近年来,人们对富硒(Se)资源的需求不断提高,土壤作为农作物生长的基础物质,富 Se 土地开发利用将是提高 Se 资源合理利用的首要切入点。选取奉节县中部青龙镇和五马镇一带土壤为研究对象,采集 247 个土壤样品,对研究区 Se 元素含量、来源、分布和影响因素特征进行分析。结果表明,研究区土壤 Se 平均含量为 0.462 mg/kg,变异程度属于高度变异。根据《天然富硒土地划定与标识》(DZ/T 0380—2021)中规定的富 Se 土地划分标准,研究区内一般富 Se 点位占比为 17.89%,空间位置上具有连续分布的特点。对 Se 等元素源解析及影响因素分析结果显示,Se 元素与 Cd 等重金属元素具有较强的伴生关系并且来源相对一致。同时,土壤有机质、硫化物、铁氧化物及磷灰石对 Se 含量影响显著,并指示受到外源迁入的影响。据正定矩阵因子分析模型定量源解析分析,研究区 土壤中 Se 来源影响顺序为外源迁入 > 地质背景 > 人为活动,贡献率分别为 70.1%、15.2% 和 14.7%,主要受河流上游地质背景影响,同时伴随着 Cd 的迁入。综合分析表明,研究区土壤环境有利于 Se 元素富集并降低重金属安全风险,具有划定天然富 Se 土地的条件,建议在后续工作中开展专项农作物调查,进一步评估农产品开发利用潜力。