芥菜籽中异硫氰酸酯提取工艺的优化

以芥菜籽为试材,异硫氰酸酯提取率为考察指标,采用超声提取法,分别设超声温度(40、50、60、70、80℃),超声时间(20、30、40、50、60 min)和乙醇体积分数(65%、75%、85%、95%、100%)3个单因素试验,再在单因素试验的基础上进行响应面试验,优化芥菜籽中异硫氰酸酯的提取工艺。结果表明:乙醇体积分数为70%,超声温度为50℃、超声时间为40 min时,芥菜籽中异硫氰酸酯提取率较高,为2.199%。     

高温烘焙前后复烤烟叶物理特性的变化

为研究高温烘焙对烤烟原料物理特性的影响,选择适宜的烘焙温度、氧含量和回潮水分等工艺参数,分析了高温烘焙前后6种不同复烤后烤烟烟叶原料的拉力、剪切力和黏附力、片烟面积分布和片烟结构的变化。结果显示：（1）烟叶原料的拉力显著降低,黏附力显著增加,剪切力的变化趋势不一致。（2）片烟特征面积呈降低趋势,但均匀性系数因不同原料而出现差异。（3）原料的大片率显著下降,小片、碎片及碎末显著增加,但是中片比例的变化不显著。烟叶物理特性的变化趋势表明高温烘焙处理对烟叶的耐加工性有一定的负面影响。因此,利用高温化学反应产生特征香气时,应尽可能选择较低的烘焙温度,提高烟叶的利用率。     

通辽地区玉米天气指数保险研究与设计

通辽地区是我国北方玉米重要产区之一,极端天气较多,严重影响农业生产。利用1989—2020年通辽地区3个气象站降水及同期玉米产量资料,设计了通辽地区玉米单因子和多因子的天气指数保险。结果表明:奈曼旗干旱灾害风险等级最高。通辽地区玉米干旱指数纯保费为343.98～386.59元/hm²,玉米干旱指数保险的触发值为-0.79。玉米生育期内,只有降水量、气温、日照时数在适宜值范围内,气象产量才达到最高。此外,玉米产量与降水量、气温、日照时数不是线性关系。通辽地区综合指数保险赔付触发值为8 752.5 kg/hm²(气象产量),玉米多因子的综合天气指数纯保费为590.02元/hm²。     

污水处理池环境细菌遗传多样性分析

以碱加热裂解法从山西农业大学污水直接和间接排放处理池自然水样中分离细菌总DNA ,以细菌 16SrRNA基因特异性引物扩增 16SrRNA基因片段。采用T -A克隆系统克隆分子量为 1339bp的PCR产物 ,构建了rDNA亚克隆文库。用三种识别六碱基的限制性内切酶两两组合消化重组质粒。共分析了两个处理池自然水样各 30个rDNA重组质粒 ,分别发现 4种和 8种细菌rDNA基因型。各基因型频率的分布变化比较大 ,最高和最低的频率分别为 0 2 5和 0 0 1。部分基因型频率间差异显著 ,遗传多样性指数分别为 0 4和 0 9。     

苦豆子条带对棉田捕食性天敌发生的影响

【目的】 研究田埂边苦豆子(Sophora alopecuroides L.)条带对棉田内捕食性天敌发生及其控蚜作用的影响,为棉花生产中田埂合理保留保育天敌的功能性杂草、促进棉田天敌保育与害虫自然控制提供科学依据。【方法】 系统调查田边苦豆子条带及棉田天敌与害虫种群,罩笼评价天敌控害功能。【结果】 苦豆子与棉花上捕食性天敌种类基本相同、群落结构相似,苦豆子条带上各类主要捕食性天敌的数量均显著高于棉田。处理棉田(棉田边有苦豆子条带)中瓢虫、草蛉、蜘蛛密度分别为对照棉田(棉田边无杂草)的1.3、3.4和4.5倍,发生高峰期较对照棉田提前一周左右。6月上旬和8月,处理棉田的捕食性天敌和蚜虫之间的益害比显著高于对照棉田。处理棉田捕食性天敌对棉蚜控害指数显著高于对照棉田。【结论】 苦豆子杂草带对有益天敌具有明显保育作用,能促进棉田捕食性天敌的发生与生物控害。     

Autonomous developmental control of human embryonic globin gene switching in transgenic mice

The mechanisms by which expression of the beta-like globin genes are developmentally regulated are under intense investigation. The temporal control of human embryonic (epsilon) globin expression was analyzed. A 3.7-kilobase (kb) fragment that contained the entire human epsilon-globin gene was linked to a 2.5-kb cassette of the locus control region (LCR), and the developmental time of expression of this construct was studied in transgenic mice. The human epsilon-globin transgene was expressed in yolk sac-derived primitive erythroid cells, but not in fetal liver or bone marrow-derived definitive erythroid cells. The absence of epsilon gene expression in definitive erythroid cells suggests that the developmental regulation of the epsilon-globin gene depends only on the presence of the LCR and the epsilon-globin gene itself (that is, an autonomous negative control mechanism). The autonomy of epsilon-globin gene developmental control distinguishes it from the competitive mechanism of regulation of gamma and beta-globin genes, and therefore, suggests that at least two distinct mechanisms function in human hemoglobin switching.     

洛玉941亩产750公斤左右生育指标研究

本文研究了洛玉941亩产750公斤左右的根、茎、叶、穗分化、籽粒形成灌浆规律,探讨了适宜的叶面积系数、干物质积累和亩穗数、穗粒数、千粒重指标。     

食用菌废培养料对小麦和大豆产量的影响

采菇之后的废培养料条施种小麦,麦收后种大豆,从两茬作物的产量看,废培养料250公斤/亩深施加少量化肥(N3.5公斤/亩,P_2O_51.75公斤/亩)与单施化肥(N7公斤/亩,P_2OP_53.5公斤/亩)相比,差异不显著;较之250公斤/亩废培养料深施不加化肥,大豆增产显著(α=0.05);较之浅施废培养料250公斤/亩和125公斤/亩两处理,小麦分别增产9.1％和11.6％,均达显著(α=0.01)水平。废培养料125公斤/亩与不施肥相比,小麦、大豆产量均未出现显著差异。     

卷铁心粗整形时力学分析及自动接片装置的改进

采用卷叠工艺生产发电机定子铁心具有省料、省时、易实现自动化生产等优点．此工艺实现自动化生产的一个重要环节是齿形带料卷曲后的自动装片和粗整形．本文对粗整形时齿形带料的受力与变形作了较全面的讨论,提出粗整形时影响带料变形的因素及其计算式,并对现有自动装片结构提出改进设计,有实用意义．     

甘肃河西一熟制灌区“吨粮田”栽培技术

以数模为主的亩产“吨粮田”栽培技术选优研究,通过3年行政技术双轨承包,完成“吨粮田”面积10.545万亩,综合单产1024.6kg,其中小麦325.5kg。研究决出“吨粮”技术模式:单幅为70cm(小麦)/80cm(玉米);小麦适宜品种为“81—811”等,亩播量30万粒;玉米适宜品种为“中单二号”。亩保苗4500～4700株;亩施纯氮30kg,P_2O_512kg;全期灌水7～8次。     

纹枯灵与担菌胺防治水稻纹枯病田间药效试验报告

田间试验了７５％纹枯灵可湿粉剂、２０％担菌胺可湿粉剂和５％井冈霉素对水稻纹枯病的防治效果。结果表明，用纹枯灵和担菌胺不同剂量处理的小区，水稻纹枯病的相对病情指数或相对病害增长率，显著低于用井冈霉素处理的小区。     

贵州芝麻不同地方种质资源产量

通过对贵州芝麻不同种质资源的产量与相关性状分析。结果表明：各个品种产量在35.72kg/亩—146.94kg/亩之间。其中产量最高的品种是P41(SI17TR-2),为146.94kg/亩;其次是P28(SI16BZ-14),为143.95kg/亩;最低的品种是P8((SI16BZ-7),为35.72kg/亩。各个个性状对产量影响的大小顺序为：单株果数>千粒重>主轴果数>主轴结果长度>生育期>单果粒数>生育期。株高、单株果数、主轴果数、单果粒数、千粒重的直接通径系数均为正值;而生育期、主轴结果长度的直接通径系数均为负值。综合考虑,P41(SI17TR-2)、 P28(SI16BZ-14)两个品种为高产品种,适宜在遵义地区大面积推广种植。     

自然水域无土栽培水稻的研究

 1989年，在自然水域的水面上进行水稻无土栽培（简称水上种稻，下同）试验，取得了初步成功。1990年在鱼塘水面试种了1.35亩水稻，其中0.7亩单季晚稻，实收亩产达496公斤。从1990年度的试验中看出水上种稻具有良好的稳产性，主要表现为：⑴不怕旱；⑵不怕涝；⑶病虫危害轻；⑷抗倒伏能力强等。本文还对水上种稻亟待解决的技术问题，解决途径及其应用前景进行了讨论。     

Evaluation of drought indices to identify tolerant genotypes in common bean bush(Phaseolus vulgaris L.)

Drought is one of the major abiotic stresses often causing negative impacts on bean crops in the Andean region in Colombia. An experiment under the greenhouse conditions was carried out to assess the effect of a prolonged drought period(15 days) at two different phenological stages(vegetative or reproductive) on grain yield and yield components of five bush bean cultivars(ICA-Cerinza, Bachue, NUA35, Bianca, and Bacatá). Nine tolerance indices including stress susceptibility index(SSI), tolerance(TOL), mean productivity(MP), geometric mean productivity(GMP), stress tolerance index(STI), yield stability index(YSI), yield index(YI), Harmonic mean(HM), and drought sensitivity index(DSI) were calculated based on grain yield under non-stressed(YP) and drought(YS) conditions. Based on the different drought indices, genotypes ICA-Cerinza and NUA35 had the best performance under drought conditions in both studied phases, which reflected in a reduction of grain yield ～≤40%. The biplot analysis also showed a clear superiority of these two genotypes at both phenological stages. Results also showed that SSI was more effective to identify genotypes less affected by drought. The above results allowed us to conclude that ICA-Cerinza and NUA35 may be considered for agricultural areas where long periods of water deficit are expected and can be used in breeding programs for drought tolerance.     

Temperatures of the martian surface and atmosphere: viking observation of diurnal and geometric variations

Selected observations made with the Viking infrared thermal mapper after the first landing are reported. Atmospheric temperatures measured at the latitude of the Viking 2 landing site (48 degrees N) over most of a martian day reveal a diurnal variation of at least 15 K, with peak temperatures occurring near 2.2 hours after noon, implying significant absorption of sunlight in the lower 30 km of the atmosphere by entrained dust. The summit temperature of Arsia Mons varies by a factor of nearly two each day; large diurnal temperature variation is characteristic of the south Tharsis upland and implies the presence of low thermal inertia material. The thermal inertia of material on the floors of several typical large craters is found to be higher than for the surrounding terrain; this suggests that craters are somehow effective in sorting aeolian material. Brightness temperatures of the Viking 1 landing area decrease at large emission angles; the intensity of reflected sunlight shows a more complex dependence on geometry than expected, implying atmospheric as well as surface scattering.     

瘠薄旱地玉米增产与培肥体系研究

1989～1990年研究结果认为,瘠薄旱地在本试验条件下亩产值与投入资金呈极显著正相关(r=0.879(?),n=8),并依投入金额呈线性关系,其回归方程为 y=32.09+5.22x;亩产子粒重与植株总干物重呈极显著正相关(r=0.955(?),n=8),并依总干物重呈线性关系,其回归方程为 y=—144.59+0.73x。试验指出,秸秆覆盖和免耕、少耕结合有提高土壤保墒蓄水作用,播种期0～10cm 土壤含水量比对照高36.9%～63.9%,抽雄至灌浆期,0～50cm 土壤储水比对照高10.5%～13.0%。有高产培肥同步效应,两年平均亩产444.9～470.3kg,比对照增产58.2%～67.2%,亩增益85～92元,水分利用率1.127～1.232kg/mm。比对照高57.1%～71.5%;比基础土壤提高有机质3.74%、全氮4.3%、全磷10.8%、速效磷15.5%,是半干旱区改造旱地中低产田的有效生产措施。     

毛白杨杂种三倍体的2n雌配子形成途径鉴定

由于受杨树大孢子母细胞减数分裂不同步性影响,通过施加理化处理诱导杨树大孢子染色体加倍授粉杂交获得的三倍体,可能既包括来源于第一次减数分裂核复原形成的2n雌配子(FDR),也有来源于第二次减数分裂核复原形成的2n雌配子(SDR),难以进行表型鉴别,而通过分子标记分析可以实现不同类型2n雌配子的区分。本研究以通过高温诱导毛白杨大孢子染色体加倍所获得的87株三倍体及其亲本为材料,从母本杂合且与父本有差异的SSR多态性引物中,筛选出5对适宜于2n配子诱导途径来源鉴定的重组率较低的SSR分子标记。在此基础上,利用这5对低重组率SSR分子标记,开展毛白杨杂种三倍体的2n雌配子诱导途径来源分析。结果表明,不同毛白杨杂种三倍体的2n雌配子相应简单重复序列区域的等位基因配置不同,利用筛选出的5对低重组率SSR标记可以实现毛白杨杂种三倍体的2n雌配子诱导途径鉴定,其中35株三倍体来源于FDR型2n配子,另52株来源于SDR型2n配子。此外,选用5个位于高重组率位点的SSR引物进行检测分析,结果验证了随机挑选的SSR引物用于鉴别结果是不完全可靠的,只有挑选低重组率的SSR位点才可能准确鉴定2n配子来源。开展毛白杨杂种三倍体的2n配子诱导途径鉴定研究,对于FDR、SDR不同形成途径的2n配子传递亲本杂合性分析,以及毛白杨三倍体育种策略制定等具有重要意义。      

Strategies to evaluate goodness of reference strips for in-season, field scale, irrigated corn nitrogen sufficiency

The nitrogen (N) sufficiency approach to assess plant N status for in-season N management requires a non-N-limiting reference to make N recommendations. Use of reference strips in fields with spatially variable soils and the impact this variability has within N enriched reference strips are not well understood. Consequently three strategies were investigated to evaluate the impact of spatially variable sandy soils within reference strips in two commercial center pivot-irrigated corn fields. Evaluation strategies were: (i) ignore soil spatial variability throughout the reference strips, (ii) account for soil variability in the reference strips based on second-order NRCS soil map units, and (iii) account for soil variability based on apparent electrical conductivity (EC_a) data as a surrogate for soil texture differences in the reference strips. A sufficiency index (SI) calculated from radiometer measured canopy reflectance data (SI_sensor) and from SPAD chlorophyll meter data (SI_meter) at two growth stages during corn vegetative growth were used to assess N sufficiency within the N enriched reference strips. By ignoring soil spatial variability in the reference strips, corn in the sandier soils was designated N deficient. Accounting for soil spatial variability using NRCS soil mapping units improved N sufficiency designations of corn in the reference strip for the different soil types contained within the reference strip but tended to designate corn in lighter texture areas within a mapping unit as N deficient. Use of EC_a as a surrogate for soil texture typically performed best for classifying corn N sufficiency throughout the reference strip and is recommended as a method to obtain reference strip normalizing values in fields with spatially variable sandy soils.