黄淮海地区不同小麦品种对雀麦的化感作用

为明确不同小麦品种对黄淮海冬小麦田常见杂草雀麦(Bromus japonicus)化感作用的差异,采用培养皿琼脂共培法,研究了该地区42个主栽小麦品种对雀麦根长、芽长、根干重及芽干重的影响,并筛选出化感抑制作用较强的小麦品种,为小麦化感种质材料的选择提供依据,以达到生态防控雀麦的目的。结果表明,不同小麦品种对雀麦根长、芽长、根干重的化感作用存在显著差异,对芽干重的化感作用不显著;小麦对雀麦根的化感作用大于对其芽的化感作用。利用RI值作为化感作用指标,并结合聚类分析,可将42个小麦品种按化感能力的强弱分为强、中、弱3类,其中泰农19、郑麦379、郑麦9023、周麦22、汶农17、郯麦98为化感抑制雀麦较强的品种。     

Impacts of dietary fat level and saturation when feeding distillers grains to high producing dairy cows

This experiment was conducted to determine whether increasing the net energy (NE_L) of a total mixed ration (TMR) with mainly unsaturated fat from corn distillers dried grains with solubles (DDGS) vs. rumen inert (RI)‐saturated fat has similar impacts on animal performance. The experiment was an incomplete Youden square with three treatments and four 28‐days periods, completed on a large commercial dairy using three early lactation pens each with approximately 380 multiparity cows. The TMR for all treatments was the same, except for 150 g/kg dry matter (DM) of each TMR which contained 90 g/kg high‐protein DDGS (HPDDGS) and 60 g/kg beet pulp (i.e. low‐fat control diet; LFC); 150 g/kg DDGS (i.e. high‐fat diet with unsaturated fat; HFU); or 111 g/kg HPDDGS, 20 g/kg beet pulp and 19 g/kg RI fat (i.e. high‐fat diet with saturated fat; HFS). The DM intake was highest (p < 0.05) for HFU‐fed cows. Milk, fat and true protein yields, as well as milk energy output, were higher (p < 0.01) when cows were fed HFS vs. HFU and LFC diets. Milk true protein concentration was lowest (p < 0.01) for HFS‐fed cows, but milk fat % was lowest (p < 0.01) for HFU and highest (p < 0.01) for HFS‐fed cows. There were numerous differences (p < 0.01) in milk fatty acid levels amongst diets. The increase in body condition score was lowest (p < 0.01) for LFC. Whole tract digestibility of acid detergent fibre was lower (p < 0.01) for LFC vs. HFS cows, and fat digestion was lowest (p < 0.01) for LFC‐fed cows. This DDGS, high in unsaturated fatty acids, was fed at high levels (i.e. 152 g/kg DM) with little impact on animal performance vs. a lower fat control diet, although addition of an RI‐saturated fat to create a diet with a similarly higher fat level resulted in higher animal productivity.     

Optimization of yield and water-use of different cropping systems for sustainable groundwater use in North China Plain

A groundwater crisis is going on in the North China Plain (NCP), due to the excessive water consumption of the traditional winter wheat (WW)/summer maize (SM) double cropping system (two harvests in one year). In order to improve the water use efficiency in this particular cropping system and to evaluate the sustainability of water usage in Chinese agroecosystems, two field experiments were conducted from October 2004 to September 2006 at two sites of the North China Plain. The field experiments included four treatments: (1) farmers’ practice (FP) with two harvests in one year (WW/SM rotation), (2) FP with reduced input (RI) of water and nitrogen (WW/SM rotation), (3) three harvests in two years (TW, 1st year: WW/SM; 2nd year: spring maize), and (4) continuous spring-maize monoculture (CS) with one harvest per year (spring maize). In the treatments RI, TW and CS, the amount and timing of irrigation and nitrogen fertilization was optimized using TDR based soil moisture measurements and the N_min-method, respectively. Data showed that the utilization efficiency of irrigation water can be improved by optimizing soil water management compared to the traditional water management (FP). However, the groundwater net consumption required for RI still surpassed 300 mm yr⁻¹. Both FP and RI, still overused groundwater resources. The groundwater consumption in the continuous spring maize (CS) was on average 139 mm yr⁻¹. Therefore, the CS system can show the potential to use groundwater sustainably in the long term. Water usage of the TW treatment was in between the water usage of the other treatments. The grain yields in the double cropping systems (FP and RI) were higher than that in the two other systems (TW and CS). But the CS treatment showed the higher W_UE than others.     

Genetic mapping of sedimentation volume across environments using recombinant inbred lines of durum wheat

SDS-sedimentation volume (SV) is a biochemical index widely used to evaluate flour quality in durum and bread wheats. Significant association between SV and endosperm proteins (gliadin, high-molecular-weight- and low-molecular-weight-glutenin subunits) have been reported. Protein loci, however, account for only a portion of the total genetic variability. The objective of this study was to identify and locate quantitative trait loci (QTLs) associated with SV in a set of recombinant inbred (RI) lines, derived from a cross between the cv.‘Messapia’ of durum wheat and the accession MG4343 of the var. dicoccoides, and characterized for 259 genetic and molecular (RFLP) markers. Significant differences were detected for the quality index in the six environments examined, while the pattern of variability was that of a quantitative trait. Regression analysis of marker loci and sedimentation volume indicated, as expected, that chromosome 1B, on which are located the Gli-B 1/Glu-B 3 loci for some gliadin and glutenin subunits, is important for wheat quality. Two additional regions located on chromosomes 6AL and 7BS, and four regions on 1AL, 3AS, 3BL and 5AL, were shown to have single-factor effects on sedimentation volume at P < 0.001 and P < 0.01, respectively. Positive effects were contributed by both parents. A multiple linear regression model consisting of seven significant loci on different chromosomes explained 62–91% of the genotypic variation of the trait. The availability of linked markers to QTLs may facilitate the genetic dissection of quantitative traits and the early selection in wheat breeding programmes.     

SEC-MALLS-RI体系测定魔芋胶分子结构特性的研究

[目的]用SEC—MAILS—RI系统测定魔芋胶的分子结构。[方法]采用凝胶渗透色谱（SEC）、多角度激光光散射（MALLS）与示差折光检测仪（RI）联用技术系统测定魔芋胶的分子量、分子量分布、分子旋转半径（RMS）及其构象。[结果]魔芋胶的分子结构特性是：重均分子量（Mω）=1．040×10^6g／mol,数均分子量（Mω）=9．395×10^6g／mol,z-均分子量（Mω）=1．329×10^6g／mol;数均旋转半径（Rn）=11O．5nm,重均旋转半径（Rω）=115．9nm,z-均旋转半径（Rz）=129．6nm;分散度分别是Mω／Mn．=1．107和Mz／Mn=1．414。分子旋转半径RMS与分子摩尔数之间的关系曲线斜率为0．40±0．00,表明魔芋胶是一个高度紧密且具有分支结构的聚合物。[结论]建立了测定聚魔芋胶分子量及其分布的激光光散射法,结合凝胶渗透色谱,能在较大范围内准确测量聚合物的绝对分子量,且试验误差较小,重现性好。     

采用HS-SPME/GC-MS/GC-Olfactometry/RI对绿茶和绿茶鲜汁饮料香气的比较分析

采用顶空固相微萃取(HS-SPME)提取绿茶和绿茶鲜汁饮料样品中的挥发性成分,用气相色谱/质谱联用技术(GC-MS)结合气相色谱-嗅觉测量法(GC-Olfactometry)以及挥发性化合物的保留指数(RI),鉴定了绿茶和饮料中的主要风味化合物,并对二者香气组成及相对含量差异进行了比较。结果表明：采用GC-MS/GC- Olfactometry/RI法能有效地鉴别和确认绿茶和绿茶鲜汁饮料中香味化合物的类别、香味强度及其对总体香气的贡献;绿茶和绿茶鲜汁饮料的香气成分在组成和含量上存在差异,绿茶中有34种嗅感物质,其中叶醇、2-乙基己醇、苄醇、1-辛醇、芳樟醇、芳樟醇氧化物、苯乙醇、己醛、(E)-2-己烯醛、苯甲醛、苯乙酮等是其主要呈香物质;绿茶鲜汁饮料含有37种嗅感物质,主要呈香物质为芳樟醇、芳樟醇氧化物、苯乙醇、香叶醇、橙花醇、橙花叔醇、(Z)-2-庚烯醛、苯甲醛、苯乙酮等。     

UV-B辐射增强对20个大豆品种生长与生物量分配的影响

在大田栽培和自然光条件下,采用模拟UV-B辐射(280～315nm)方法,研究了UV-B辐射增强对20个大豆品种生长和生物量分配差异的影响。结果表明,UV-B辐射导致20个大豆品种叶片、根与茎、籽粒的生物量和总生物量降低,更多的生物量分配到籽粒。株高、节间长、节数对UV-B辐射增强响应具有品种间差异。株高和节间长对UV-B辐射响应具有一致性,呈极显著正相关,株高与节数无明显相关。20个大豆品种籽粒的粒径、百粒重对UV-B辐射均表现出不同程度的敏感性,其中20个品种的粒径降低程度达极显著水平,15个品种的百粒重降低程度达显著水平。根据响应指数(RI),耐性品种(RI≥-38.6)为:兰引20>云南97801>云南97929>云南97506>绿滚豆。敏感品种(RI≤-94.3)为:环县黄豆>云南97501>陇豆-1>土黄豆-1>灵台黄豆。     

几个玉米自交系的耐旱性鉴定

对国内20余份骨干自交系进行耐旱性鉴定,测定其ASI、单穗平均产量、出籽率等指标,对筛选出的6个自交系进一步鉴定分析其抗旱指数、RI(修).结果表明:Qi319、Ye107、F178耐旱性好,且自身产量较高,可作为耐旱种质资源加以利用。