高等级公路测量基准面的确定及长度变形分析

分析了高等级公路平面控制网导线边投影长度变形与测区平均高程及投影带宽度的关系．根据长度变形是否满足国家标准GB50026－93要求（≤2．5cm／1km）而确定坐标系统．给出了不同坐标系统之间的换算关系．文中算例表明：用简单算法能达到公路工程测量的精度要求．     

Molecular typing of Streptococcus agalactiae isolates from fish

The genetic variability among Streptococcus agalactiae isolates recovered from fish was characterized using single-stranded conformation polymorphism (SSCP) analysis of the intergenic spacer region (ISR), and amplified fragment length polymorphism (AFLP) fingerprinting. A total of 46 S. agalactiae cultures isolated from different fish species and geographic origins as well as related reference strains were included in the study. ISR-SSCP divided the S. agalactiae isolates analysed into five distinct genotypes. Genotype 1 grouped all Kuwait isolates while genotype 4 clustered the majority of non-Kuwait isolates (USA, Brazil and Honduras). AFLP analysis offered a higher resolution level by dividing the isolates into 13 different genotypes. Two different AFLP profiles were identified within the Kuwait isolates. When data from both ISR-SSCP and AFLP were combined through a multidimensional analysis (MDS), a good correlation between geographical origin and genotypes was observed. Both AFLP and ISR-SSCP revealed genetic differences between S. agalactiae isolates from fish. While AFLP offered a higher resolution, ISR-SSCP also provided valid information being a simpler and faster method.     

泾惠渠灌区畦长对夏玉米耗水特性和产量影响

泾惠渠灌区中畦田规格参差不齐,灌区由于畦田过长而造成的灌溉水量浪费屡见不鲜,不仅没有形成高产而且极大的造成了水资源的浪费。通过大田与小区试验相结合,以当地农民习惯的灌溉方式为对照,设置3个灌溉畦长处理(80、120、240 m),每个处理设置3次重复,改水为80%。研究了灌溉畦长对夏玉米在生育期内的耗水特性和产量的影响,土壤水分分布与产量及其构成因素的关系等问题,选择出兼顾节水高产可行的最优畦长。研究结果表明:在生育期灌水后,80和120 m处理畦长内畦首、畦中和畦尾的土壤相对含水率较为均匀无显著差异,240 m处理畦长畦首、畦中和畦尾的土壤相对含水率产生显著性差异;80和120 m处理夏玉米在畦首、畦中和畦尾灌水均匀度较为平均且无显著差异,240 m畦长处理差异较为显著,且80 m畦长处理产量分布最为平均、平均水分利用效率最高产量为1.021 839万kg/hm2,水分利用效率为25.12 kg/(hm2·mm)。综合夏玉米产量及其分布、水分利用效率等因素,在泾惠渠灌区80 m的灌溉畦长是兼顾节水高产的最适宜畦长,该结论以期为泾惠渠灌区大田作物高产节水提供一定理论依据。     

添加麸皮与纤维素酶对笋壳青贮后氰甙含量的影响

[目的]研究添加麸皮与纤维素酶对笋壳青贮后氰甙含量的影响。[方法]采用异烟酸—吡唑啉酮比色法研究添加麸皮与纤维素酶对笋壳青贮后氰甙含量的影响。[结果]添加麸皮与纤维素酶均可降低笋壳青贮后的氰甙含量。麸皮添加水平越高,青贮笋壳毒性越低,当麸皮添加水平为15%时笋壳青贮后氰甙含量最低。[结论]该研究可为笋壳饲料的资源化利用提供理论依据。     

Effects of Soil Temperature on Growth and Root Function in Rice

Abstract

The objective of this study was to clarify the effects of soil temperature in the stage from late tillering to panicle initiation (SI) and during the grain-filling stage (SII) on grain setting, dry matter production, photosynthesis, non-structural carbohydrate (NSC), xylem exudation and abscisic acid (ABA) levels in rice (Oryza sativa L. cv. Koshihikari). Rice plants were exposed to four different soil temperatures during SI or SII: 17.5, 25, 31.5 and 36.5°C (ST18, ST25, ST32 and ST37, respectively). The yield, yield components, grain filling and quality in SI were negatively influenced by high soil temperature of 37°C. On the other hand, there was no significant difference in those characters among temperature treatments in SII. The root/shoot ratio was smallest in the ST37 plants in both SI and SII, mainly due to their lighter root weight. At 7 days after initiation of treatment (DAT) in both SI and SII, the photosynthetic and xylem exudation rate tended to increase slightly as soil temperature increased up to 32°C. At 21 DAT, however, the photosynthetic rate was lowest in ST37, with concurrent decrease of diffusion conductance and SPAD value. In addition, decrease of NSC concentration in stem and xylem exudation rate, and increase of ABA level in leaves and xylem exudate were observed in ST37 plants at 21 DAT. These results suggested that high soil temperature before heading especially influenced yield, grain quality and plant growth. Possible mechanisms of the effect of soil temperature are discussed.     

白花败酱组织培养及快速繁殖研究

选取长势较好、无病害野生白花败酱植株的茎尖及茎段作为外植体进行组织培养,以MS为基本培养基,设计不同激素浓度配比试验,筛选最佳培养基配方。结果表明:采用0.1%HgCl2对外植体进行消毒,茎尖最佳消毒时间为10 min,茎段为15 min;最佳诱导培养基配方是MS+6-BA 3.0 mg/L+NAA 0.1 mg/L,诱导率100%,增殖培养基MS+6-BA 2.0 mg/L+NAA0.2 mg/L,增殖倍数7.8;生根壮苗培养基是MS+NAA 1 mg/L+马铃薯5%。     

麻竹笋用林施肥效果试验

对麻竹笋用林进行施肥试验研究，分析得知，鸡粪、复合肥、配方肥3种肥料对竹笋产量和经济纯收入有显著影响，均与竹笋产量、经济纯收入呈抛物线型关系，竹笋产量、经济纯收入随施肥量增加呈现先上升后下降的趋势；3种肥料的影响程度顺序依次为：配方施肥、鸡粪、复合肥，配方施肥的最佳施肥方案为鸡400＋复60＋硫酸锌0．9。     

Floral induction (FI) in longan (Dimocarpus longan, Lour.) trees. III: Effect of shading the trees on potassium chlorate induced FI and resulting hormonal changes in leaves and shoots

Previous experiments demonstrated that treatment of longan trees with potassium chlorate (KClO₃) induces “off season floral induction” (FI) even in the absence of the naturally required cool temperature [Manochai, P., Sruamsiri, P., Wiriya-alongkorn, W., Naphrom, D., Hegele, M., Bangerth, F., 2005. Year around off season flower induction in longan (Dimocarpus longan, Lour.) trees by KClO₃ applications: potentials and problems. Sci. Hortic. 104, 379–390]. Potassium chlorate, however, cannot replace the presence of functional mature leaves and sufficient light intensity. Here we examined in more detail the effect of shade (about 10% of natural sunlight) on KClO₃ affected hormone concentrations/transport of leaves and shoot apical buds (SAB) and their interactions with FI.     

金光杏梅叶面积回归测算研究

以金光杏梅成熟叶片为试材,研究了叶长、叶宽与叶面积的关系.结果表明:叶长、叶宽与叶面积均呈正相关关系.叶长、叶宽与叶面积之间的相关系数分别为0.7084、0.8546,叶长和叶宽与叶面积的复相关系数为0.9868,在0.01水平下均达到了极显著水平.在此基础上建立了叶长(x1)、叶宽(x2)、叶长和叶宽与叶面积(y)之间的回归方程y=61.4140x1-2 480.6、y=28.7600x2-0.8546、y=17.6276x1+41.2594x2-1 078.4906,3个回归方程均可用于测算金光杏梅的叶面积,其中以叶长和叶宽与叶面积的二元回归方程测算结果更为精确.在具体应用中,可根据所要求的精确度进行选择.     

Occurrence of microsatellites in spinach sequences from computer databases and development of polymorphic SSR markers

Microsatellites are valuable tools as molecular markers in plant breeding. To establish genetic linkage maps or for population studies, information about the occurrence and usability of microsatellite markers in different species is necessary. Sequences of spinach Spinacia oleracea from computer databases were therefore searched for the presence of microsatellites. Sixty simple sequence repeats were found in 237 spinach sequences with a total of 349.4 kb DNA. After removing duplicated sequences, 50 different microsatellites with various motifs remained. Differences between nuclear and chloroplast DNA were not in the number of microsatellites but in their type and length. Chloroplast sequences from spinach contain only short strings of A and AT repeats, whereas nuclear sequences show a wider variety of motifs. Flanking primers for polymerase chain reaction (PCR) analysis were designed for 13 of these microsatellites and tested with two different varieties of spinach. Twelve primer pairs gave amplification products and seven of these showed polymorphisms in the variety ‘Wiremona’ but only one in the variety ‘Monatol’. These markers may be used for linkage analysis or population studies in spinach.