酵母硒对断奶獭免生长性能的影响

选择35日龄健康獭兔80只,按体重随机分为4组,在基础日粮中分别添加0、0．1、0．3、0．5mg／kg酵母硒进行饲喂,试验期30d。结果表明：添加酵母硒能提高獭兔的日增重、血清总蛋白、球蛋白与T3水平,降低料重比与血清T4水平,其最适添加量为0．3mg／kg。     

Use of NH4 HCO3‐DTPA soil test to assess availability and toxicity of selenium to alfalfa plants

Abstract

This study was carried out to determine if ammonium bicarbonate‐DTPA soil test (AB‐DTPA) of Soltanpour and Schwab for simultaneous extraction of P, K, Zn, Fe, Cu and Mn can be used to determine the availability index for Se. Five Mollisols from North Dakota were treated with sodium selenate and were subjected to several wetting and drying cycles. These soils were extracted with hot water and with ammonium bicarbonate‐DTPA (AB‐DTPA) solution for Se analysis. Alfalfa plants were grown in these soils in a growth chamber to determine plant uptake of Se. In addition to the above experiment, coal mine soil and overburden materials from Western Colorado were extracted and analyzed as mentioned above.

It was found that hot water and AB‐DTPA extracted approximately equal amounts of Se from Mollisols. A high degree of correlation (r =0.96) was found between Se uptake by plants and AB‐DTPA extractable Se. Extractable level of Se in treated soils was decreased with time due to change of selenate to less soluble Se forms and plant uptake of Se. An AB‐DTPA extractable Se level of over 100 ppb produced alfalfa plants containing 5 ppm or higher levels of Se that can be considered toxic to animals. Soils with about 2000 ppb of extractable Se were highly toxic to alfalfa plants and resulted in plant concentrations of over 1000 ppm of Se. The high rate of selenate (4ppm Se) was less toxic to alfalfa plants in soils of high organic matter content. This lower toxicity was accompanied with lower extractable levels of Se.

The AB‐DTPA solution extracted on the average about 31% more Se than hot water from the mine and overburden samples and was highly correlated with the latter (r =0.92). The results indicated the presence of bicarbonate‐exchangeable Se in these materials.     

The determination of extractable plant available selenium from soils by electrothermal atomic absorption spectroscopy

Abstract

Plant available selenate was measured in a soil extract by electrothermal atomic absorption spectroscopy. Selenate in soil was first extracted with potassium sulfate then extracted into toluene fron an iodide‐sulfuric acid media. Aliquots of the toluene were injected into the graphite furnace for selenium determination. Quantities of extractable selenium measured using the electrothermal atomic absorption method compared favorably with the results of determinations using a fluorometric technique on aliquots of the soil extract. The simplicity of the procedure allowed for the precise determination of soil selenate in a brief period of time.     

富硒玉米子粒中硒赋存形态研究

研究了富硒玉米子粒中硒的分布规律和赋存形态。结果表明,在供试玉米中,硒主要以有机结合态的形式存在,其含量占总硒的比例接近90%;在有机态硒中蛋白质硒含量较高,多糖中硒的含量较低;在蛋白质硒中以碱溶蛋白质中硒的含量为最高,占总硒的50.62%。因此,在富硒玉米的深度开发中,碱溶的弱酸性组分适用于深加工,成为补硒食品或添加剂。     

乳牛的血硒水平及其与谷胱甘肽过氧化物酶活性的关系

应用2,3-二氨基萘荧光分析法测定了南京地区L牧场和C牧场乳牛的血硒水平,泌乳母牛为0.088±0.020ppm(n=31),种公牛为0.161±0.015ppm(n=6),两者之间差异极显著(P<0.001)。同时用改进的Hafeman法测定了血液中GSH-Px的活性,泌乳母牛为65.52±22.56单位(n=32),种公牛为116.73±18.65单位(n=6)两者之间差异极显著(P<0.001)。相关析分表明,全血谷胱甘肽过氧化物酶(GSH-Px)活性与血硒水平呈高度正相关(r=0.854,n=37,P<0.0005),从而证实,全血GSH-Px活性的测定结果可用于推测田间条件下乳牛体内硒的状态。另外,本文做了血硒的回收试验和重复性测定,并对其测定方法进行了讨论。     

茶叶的硒营养研究进展

缺硒会使人体产生多种疾病.茶树有较强富集硒的能力,经常饮茶可以改善人体的硒营养,起到预防疾病的效果.论述了茶树的硒营养特点,为富硒茶的开发应用提供理论依据.     

不同种类蔬菜硒元素含量比较试验

通过开展西兰花、白菜花、结球甘蓝、大白菜、娃娃菜5类作物自然富硒和添加硒肥对比试验,研究分析不同作物对硒元素的富集能力。结果表明:自然富硒处理中叶菜类蔬菜不同品种硒含量差异不大,花菜类蔬菜不同品种硒含量差异较大;添加硒肥处理中不同种类蔬菜富集硒的能力不同,同类蔬菜不同品种富集硒的能力也不同。     

Variations in annual precipitation and selenium accumulation by Milk‐Vetch

Four Se accumulators and two non‐accumulator plants were examined for their Se content in wet and dry years. No significant change in Se quantity was noted in the non‐accumulators in relation to variations in annual precipitation. However, the concentration of Se found in accumulator plants is significantly higher in wet years than in dry ones. Furthermore, in wet years there is a higher percentage of water soluble Se in these plants than in dry ones. The soils supporting these plants were also examined for their Se content. In dry years these soils contain more water soluble Se than in wet ones but, in dry years, this form of Se is less available due to the lack of available moisture. High precipitation may tend to reduce absorption of Se by plants by diluting the water soluble Se present in the soil solution, but it is clear that it also promotes absorption of Se by encouraging vigorous growth of these accumulator plants.     

硒对植物的生理作用及富硒瓜菜研究进展

中国72％的土壤缺硒,硒对人体健康发挥着重要作用。根据有关文献阐述了富硒瓜菜的特点,瓜菜硒含量的国家标准;植物对硒的吸收、转运及同化的机理;硒对作物产量、品质、种子萌发、根系活力和叶绿素含量等的影响。此外还介绍了硒对植物矿质营养吸收、抗逆性、酶活性、抗氧化作用及重金属拮抗等的影响;简述了硒在厚皮甜瓜和西瓜上的研究现状：提出了富硒农业发展中存在的问题及未来的发展方向。     

不同硒源对大麦农艺性状的影响及富硒效应研究

为了探明不同硒源对大麦的效应,对六个大麦品种(系)分别施用三种硒源(富硒复混肥、硒矿粉、亚硒酸钠)后的农艺性状及籽粒含硒量进行了分析,结果表明:①不同硒源均能提高大麦籽粒的含硒量,其增加量为0.016～0.087 mg/kg,增幅为14.4%～78.0%,富硒复混肥的效果较优;②不同大麦品种(系)施硒的籽粒含硒量为0.133～0.187mg/kg,比对照提高10.36%～80.65%;③施硒对大麦生育期无明显影响,但株高和穗长有增加趋势,千粒重有降低趋势.