白沙绿茶和红茶中硒含量的优化测定

采用氢化物发生原子荧光法测定海南白沙绿茶和红茶中的硒含量，研究了仪器条件和还原剂等对硒原子荧光强度的影响。结果表明，最佳仪器条件为光电倍增管负高压300 V，灯电流80 mA；还原剂浓度为1.5%，载流盐酸浓度5%。该方法线性范围0～10 μg/L时，与荧光值线性关系好，回归方程为y＝75.949x－8.795 4，相关系数r＝0.999 8。方法检出限是0.024 μg/kg，测定标准物质中硒的回收率为97.7%～109.6%。以国家标准物质茶叶(GBW10016)为监控样品，标准物质茶叶测定值与标准值吻合。白沙绿茶和红茶硒元素含量分别是34.4和20.1 μg/kg。该方法线性范围宽、灵敏度高、检出限低，可用于茶叶等样品中硒元素含量的准确测定。     

高效液相色谱法测定龙眼果实中ATP、ADP、AMP的含量

摸索了一种基于高效液相色谱仪快速测定龙眼果实腺苷三磷酸(ATP)、腺苷二磷酸(ADP)、腺苷一磷酸(AMP)含量的方法.该方法利用磷酸盐缓冲液(pH7.0)作为单一流动相,流速设定为1 mL/min,停止时间13 min,检测波长254 nm,无参比波长.ATP、ADP和AMP浓度在5～50 mg/L范围内与相应的色谱峰面积呈完美的直线关系(决定系数R2均为1.000),回收率95.2％ ～97.5％,保留时间分别为8.651、9.844和11.457 min.该方法测定结果表明,果实腺苷含量水平分别为30.0、6.5和2.0μg/g,能荷值为0.86.     

我国部分大米含硒量分析及生物硒肥对籽粒硒水平的影响

用原子荧光分光光度法测定了江苏省 5 2个不同品种大米样品、全国部分省市 30个大米样品以及两种用不同硒生物肥生产的富硒大米的含硒量 ,研究了生物硒肥对大米含硒量及硒形态的影响。结果表明 ,江苏省的大米含硒量为 0 .0 15～ 0 .0 5 6 mg/kg,平均为 0 .0 35 mg/kg± 0 .0 0 9mg/kg;全国部分地区的大米含硒量为 0 .0 11～ 0 .0 5 5 mg/kg,平均为 0 .0 2 5mg/kg± 0 .0 11mg/kg,湖北恩施的大米含硒量达 0 .2 6 2 mg/kg。依据中国营养学会推荐的谷物食品摄入量 ,推算江苏省和其他地区居民从大米中摄入的硒分别为 10 .5～ 17.5 μg/(d·人 )和 7.5～ 12 .5 μg/(d·人 )。在水稻齐穗期喷施硒 2 0 g/hm2 ,大米含硒量由普通大米的 0 .0 71mg/kg分别提高到 0 .4 71mg/kg和 0 .6 4 0 mg/kg,有机硒比例分别由普通大米的 78.38%提高到 87.11%和 89.0 8%。外源硒能显著提高大米的含硒量和有机硒含量及比例     

揭东县玉湖镇坪上绿茶品质特性及天然硒含量初探

本文主要对揭东县玉湖镇的地方特色茶——坪上绿茶的感官品质、生化品质及含硒量进行了初步取样分析.坪上绿茶分重炒青和轻炒青,其成茶外形、内质上均有着明显的差异.经年存放的坪上绿茶,表现出陈香浓醇、甜香显露,汤色褐红,滋味浓厚、回甘的特点.坪上绿茶新茶的水浸出物含量为36.04％～45.44％,茶多酚含量为20.08％～32.24％,氨基酸含量为1.20％～3.81％,咖啡碱含量为1.18％～3.68％,可溶性糖含量为6.27％～7.94％.符合坪上绿茶滋味浓（厚）爽回甘的特点.经年存放的坪上绿茶,随着贮藏年份的增加,其品质成分均呈现缓慢下降的趋势,滋味逐渐由浓爽变为醇厚.坪上绿茶的含硒量为0.063～0.320mg/kg,其中有1个茶样含硒量为0.320mg/kg,达到富硒茶标准（0.25～4.0mg/kg）,有6个茶样的含硒量为0.1 00～0.1 75mg/kg,有2个茶样的含硒量较低,为0.063、0.085mg/kg,低于0.100mg/kg.通过对全镇茶园土壤及茶叶含硒量进行广泛取样分析,有可能发现可规模开发的天然富硒茶园及茶树品系.     

振荡发酵生产球形细菌纤维素

采用振荡发酵生产球粒形细菌纤维素,以提供外观和口感新颖独特的纤维素产品.结果表明:培养基的碳源浓度、椰子水添加量、装瓶量、振荡速度等对纤维素颗粒的形状、产量影响较大.最佳发酵工艺为:15g/L蔗糖,(NH4)2SO43 g/L,KH2PO43g/L,MgSO4·7H2O 0.2 g/L,酵母粉0.5 g/L,20%(ν/ν)椰子水,20%(ν/ν)菠萝汁,500mL三角瓶装200mL发酵液(液高3.4 cm),初始pH4.5,150 r/min,30℃振荡培养10d.在此条件下,可得到粒形均匀(φ 0.8～1.0 cm)、产量较高(3.15 g/L)的球形细菌纤维素.这种新型纤维素球粒能满足食品工业和消费者多元化的需求.     

土壤施用亚硒酸钠对乌龙茶硒含量的影响

通过大田试验研究土壤施用亚硒酸钠对乌龙茶硒含量的影响.设计亚硒酸钠施用量CK (0g Se·hm 2)、S1(500 g Se·hm-2)、S2 (1000gSe· hm 2)和S3 (2000 g Se·hm 2)4个处理.结果表明,土壤施用亚硒酸钠对茶叶产量没有产生显著影响,土壤施用亚硒酸钠可以显著提高茶叶的硒含量,提高幅度随着施用量的增加而增加.土壤施硒处理,当年茶叶硒肥新稍吸收率在0.040％～0.066％之间,土壤施用亚硒酸钠中硒的利用率较低.     

高效液相色谱测定木薯块根β-胡萝卜素的方法优化

为确定高效液相色谱法测定木薯β-胡萝卜素的最佳方法,以丙酮/石油醚(2/5,V/V)为提取液,甲醇/叔丁基甲醚(70/30,V/V)为流动相,对白心木薯SC101和蛋黄木薯SC9块根β-胡萝卜素保留时间及其分离情况进行研究。检测条件为：色谱柱YCM C30,柱温30℃,流速为1 mL/min等度洗脱。结果显示：该方法精确度和重复性的变异系数均小于5%,保留时间为12.65 min,在2～30 μg/mL浓度范围内线性关系良好(y= 209.11x－14.114,R2＝0.9993);平均回收率为81%～92 %。采用改进的HPLC法对木薯块根β-胡萝卜素进行测定,数据稳定性好,分析时间比已报道的方法缩短30 min以上,适用于快速定量分析木薯块根的微量β-胡萝卜素含量。     

一种安全简便测定椰子胚乳乙酰辅酶A羧化酶活性的方法

建立利用HPLC测定椰子胚乳乙酰辅酶A羧化酶(ACCase)活性的方法。色谱柱为德国MN nucleosil C18(4.60 mm i.d×250 mm,5.0 μm),流动相为10 mmol/L 磷酸二氢钾(pH 6.7)︰甲醇＝90︰10(V︰V)。结果表明：Malonyl-CoA浓度在0.02～0.12 μg/mL,色谱方法有良好的线性关系,线性相关系数为0.999,Malonyl-CoA最低检测浓度为0.02 μg/mL,最终测定椰子胚乳ACCase活性为1.20 ng Malonyl-CoA/min/μg酶蛋白。     

香蕉纤维化学脱胶工艺优化

采用化学脱胶处理香蕉纤维,对一煮和二煮工艺中的参数进行优化设计,以残胶率和残余木质素含量为指标对化学脱胶效果进行评价。结果显示：一煮工艺中,NaOH浓度、煮炼时间、Na2SO3及Na5P3O10浓度是影响脱胶效果的主要因素,优化后得出最佳工艺参数为：NaOH浓度为14 g/L、煮炼时间150 min、Na2SO3浓度3％﹑Na5P3O10浓度2.75％,残胶率为9.19％,残余木质素率为7.87％。二煮工艺中确定了NaOH浓度、H2O2浓度、处理时间为主要影响因素,最佳工艺条件为：NaOH浓度14 g/L、H2O2浓度为8％、处理时间120 min,残胶率达8.85％,残余木质素达4.68％。     

原子荧光光谱法对红景天制剂中砷、汞含量的检测

目的建立红景天制剂中砷、汞含量的测定方法。方法以HNO_3-H_2O_2为消解剂对试样进行微波消解,用原子荧光光度计对样品进行测定。结果砷、汞的线性范围分别为0～10μg/L、0～1.0μg/L,线性方程分别为IF=241.67981c-21.74423(R=0.99987)、IF=1322.4766c-8.1358(R=0.99982)。在红景天膏剂、片剂和颗粒中的砷含量分别为0.362、0.280、0.210 mg/kg,汞含量分别为0.17、0.022、0.031 mg/kg。砷、汞检出限分别为0.02、0.01μg/L,平均回收率分别为4.31%～101.09%、 93.45%～102.62%(n=5)。结论该方法操作简便,结果准确可靠。     

豫北优质大豆产业发展策略

针对豫北地区的大豆生产现状，从气候、土壤、品种、生态因素及市场需求等方面提出了优质大豆的发展策略与途径。     

湖南沅陵4种绿茶品质成分分析

以长沙县高桥相同嫩度茶鲜叶原料采用卷曲形毛尖茶加工工艺制绿茶为对照,分别对沅陵县齐眉翠峰、凤娇碣滩茶、干发茶和军大坪茶4种绿茶的主要生化成分与感官品质进行初步分析。结果表明,沅陵4种绿茶的茶多酚总量28.76%~30.34%,游离氨基酸总量2.35%~3.22%,咖啡碱含量3.00%~3.63%,水浸出物含量37.26%~40.07%,可溶性糖总量5.46%~5.65%,可溶性蛋白含量1.50%~1.74%,类黄酮化合物总量1.16%~1.79%,叶绿素总量1.36%~2.01%,儿茶素总量13.53%~16.20%。与对照相比,4种绿茶的茶多酚、可溶性糖和儿茶素总量均高于对照,除齐眉翠峰外其余3种茶样水浸出物和叶绿素总量均高于对照,除干发茶外其余3种茶样类黄酮化合物总量均高于对照。     

Comparisons of methods of scheduling irrigations of potatoes

Irrigation of Netted Gem potatoes was scheduled during three growing seasons by three methods: (a) when plants displayed first visual symptoms of moisture stress, (b) when indicated by a soil moisture budget involving estimated evapotranspiration, and (c) on the basis of tensiometer readings of soil moisture suction. When the tensiometer method of scheduling was used, the mean yields of tubers were 55.0 and 25.8 cwt/acre (6160 and 2890 kg/ha) higher than those obtained with the other two scheduling methods. Methods did not affect the specific gravity of potatoes. Method (a) scheduled irrigations least frequently. Scheduling by the budget method was not always adequate because it was based on the assumption that the crop extracted water from a constant 4 ft (1.2 m) profile from planting to full vegetative growth. In one year the budget method scheduled the first irrigation earlier than necessary and delayed the second irrigation during a critical period of crop growth. From full vegetative cover to harvest the irrigation schedules were alike for both the budget and tensiometer methods.     

Analysis of nutritional components of eight famine foods of the Republic of Niger

In the western Sahel, indigenous plants become important staples when cereal harvests are inadequate to support populations inhabiting that region of Africa. The purpose of this study was to assess the nutrient content of several of these edible wild plants. The leaves of the following seven plant foods were analyzed: Ziziphus mauritiana, Cerathotheca sesamoides, Moringa oleifera, Leptadenia hastata, Hibiscus sabdarifa, Amaranthus viridi, and Adansonia digitata. The fatty acid, vitamin E, carotenoid, selected mineral and amino acid contents of these plant foods were determined. These same analyses were performed on the fruit of the Adansonia digitata. In quantitative and qualitative terms, Amaranthus viridis was found to be an excellent source of protein. Its amino acid composition compared favorably to that of a World Health Organization (WHO) protein standard. It also contained considerable amounts of the two fatty acids that are essential in humans (linoleic and -linolenic) and a number of minerals including iron, magnesium, calcium and zinc. The leaves of Hibiscus sabdarifa contained an appreciable quantity of protein the composition of which was comparable to the WHO standard. The mineral content of the leaves of this plant was also exceptionally high; noteworthy was its high zinc content. H. sabdarifa also contained significant quantities of the two essential fatty acids. Ziziphus mauritiana was an excellent source of the essential fatty acid linoleic acid and several of the metals including iron, calcium, magnesium and zinc. Its content of other essential nutrients, however, was rather low. In general, Adansonia digitata leaves were nutritionally superior to the fruit of the tree; however, the fruit did contain useful quantities of potassium, phosphorus, zinc and -linolenic acid. The Leptadenia hastata leaves were an especially good source of lutein and -carotene. These data should be useful to the people who inhabit the western Sahel in helping them devise healthy diets during times when cereal staples are in short supply.     

狗牙根诱变后代抗寒性评价

通过电解质外渗法和匍匐茎恢复试验对‘阳江’狗牙根及其12个通过形态鉴定选出的坪用价值高且花序密度低的诱变后代进行抗寒性鉴定。电解质外渗法结果表明:诱变后代间的抗寒性具有较大差异,其叶片半致死温度(LT₅₀)的变异范围为-7.6～-0.2℃(最低值与最大值相差7.4℃);参试材料抗寒性由强到弱依次为M18>M4>M26>M28> M22>阳江>M29>M31>M10>M37>M16>M1>M25,其中,有5个诱变后代抗寒性优于亲本,分别是M18、M4、M26、M28、M22。匍匐茎恢复实验结果表明:诱变后代M1、M22、M26、M31、M25在0℃和-5℃低温胁迫后的恢复生长率都高于亲本,恢复能力均优于亲本;M10、M37、M28在-5℃低温胁迫下,恢复生长能力低于亲本,抗寒性相对较弱,M16和M4在0℃和-5℃低温胁迫下,恢复生长率都低于亲本,抗寒性明显弱于亲本。综合2种方法鉴定结果显示:诱变后代M1、M25的恢复能力较强;M4、M28的叶片抗寒性较好,青绿期较长;M22、M18、M26的叶片抗寒性和匍匐茎恢复能力均较强;M29,M31的叶片抗寒性和匍匐茎恢复能力与亲本相似;M10、M16、M37的叶片抗寒性和匍匐茎恢复能力均较弱,整体抗寒性较弱。     

吉林省平安农业科学院大豆所大豆研究工作报告

1　吉林省平安农业科学院大豆研究工作简介吉林省平安农业科学院大豆研究所 ,设在吉林省长春市西安大路种子大厦内。现有科技人员 6人 ,其中研究员 2人 ,农艺师 2人 ,技术员 2人 ,定向培养研究生 2人。大豆研究所的主要任务是选育稳产、高产、优质及抗病虫大豆新品种 ;同时密切     

巴西橡胶树MADS-box基因家族6个成员的染色体物理定位

MADS-box基因家族广泛分布于真核生物中,巴西橡胶树的MADS-box基因家族主要参与花形态建成,对生殖生长起到重要的调节作用。目前,MADS-box基因家族的26个相关基因已被克隆分析,但它们在染色体上的具体位置还未确定。本研究以巴西橡胶树‘热研7-33-97’品种为材料,将MADS-box基因家族的6个成员（HbAGL8、HbAG15、HbAGL30、HbTT16、HbAP1和HbSVP1）定位在细胞核染色体上,通过双探针荧光原位杂交技术（FISH）对巴西橡胶树MADS-box基因家族的这6个成员在细胞核染色体上进行物理定位分析。结果表明：MADS-box基因家族的6个基因分别位于不同的染色体上,其中HbAGL15、HbAG8、HbAG30和HbSVP1基因定位在第4、5、7和8号染色体长臂上,其信号位点到着丝粒的平均百分距离是11.85、39.71、48.94和6.70;HbTT16和HbAP1基因定位在第1和13号染色体短臂上,其信号位点到着丝粒的平均百分距离是22.19和18.01。本研究结果揭示了巴西橡胶树MADS-box基因家族的6个成员在细胞核染色体上的实际位置,展现家族基因之间的分布特点和连锁遗传关系,不仅丰富了橡胶树分子细胞遗传学信息,也为橡胶树的分子辅助育种和比较基因组学研究提供了分子细胞遗传学的科学理论依据。     

Comparison of two methods of PCNB application for control of Rhizoctonia infection of potatoes

A broadcast application of PCNB (Terraclor) resulted in a reasonably uniform distribution of the chemical in the soil with the concentration decreasing in a linear fashion with increasing depth in the soil profile. A banded application resuluted in a considerably higher chemical concentration at the 4–6 inch depth than at the 0–2 or the 2–4 inch depths. The problem of the lack of uniformity of chemical distribution could probably be solved by altering nozzle placement and size and allow use of the band method of application to minimize grower cost. More complete disking in the case of the broadcast treatment would probably result in a relatively uniform distribution of the chemical but at higher cost to the grower. PCNB application rates of 10, 15 and 25 lbs per acre broadcast and 71/2, 10 and 121/2 lbs per acre in a band significantly reduced the severity ofRhizoctonia infection of Russet Burbank potatoes but did not increase potato yields significantly.     

Prediction of the digestibility of the diet of horses: evaluation of faecal indices

Data from in vivo digestibility trial with four to six horses fed twenty-seven forage-based diets are used to calculate prediction equations for the digestibility of dry and organic matter, based on the crude ash (CA), crude protein (CP) and crude fibre (CF) contents of diets and faeces. The most precise prediction of dry-matter digestibility (r.s.d. = 0.032, R²= 0.80) was derived from a multiple regression including faecal (CP, CF) and dietary parameters (CF). Among faecal parameters, CP was the best single predictor of both digestibility (r.s.d) = 0.040, r²= 0.63) and dietary CP content (r.s.d = 0.028, r²= 0.59). For biological reasons we propose a non-linear model that allows prediction of dry- and organic-matter digestibility from faecal CP Content with reasonable Precision (r.s.d = 0.038, 0.036, r²= 0.65, 0.74, respectively). This will be adequate for many studies, especially for free-living animals in rangelands.