2-甲氧基-4-乙酰胺基苯甲酸甲酯合成方法的改进

以ＰＡＳ－ Ｎａ 为原料，经水溶液中酰化后，再经酯化与醚化一步反应制得２－ 甲氧基－ ４ － 乙酰胺基苯甲酸甲酯，总收率８１％ 。     

NITROGEN FIXATION OF Azorhizobium IN ARTIFICIALLY INDUCED ROOT PARA-NODULES IN WHEAT

Nodule-like structures (para-nodules) can be induced in wheat roots by low concentrationsof 2,4-dichlorophenoxyacetic acid (2,4-D), a synthetic analogue of the plant growth hor-mone indole-acetic acid. Growth of nodulated wheat plants was not affected by 2,4-D treat-ment. Infection of these?para-nodules by adding oxygen-tolerant Azorhizobium caulinodans isolat-ed from stem nodules of the tropical legume Sesbania rostrata resulted in massive prolifera-tion of bacterial cells in the intercellular spaces as well as inside the para-nodular cells.Para-nodules colonized by Azorhizobium coulinodans not only reduced acetylene, but alsotransferred fixed nitrogen to the plant, contributing up to 16--23% of the nitrogen budgetof infected wheat.     

氮离子束注入对新疆春小麦M1代生物学效应的影响

为了探索离子束诱变育种的合适剂量,用5种剂量处理2个品种,对两个品种的出苗率、分蘖率、小穗数、穗粒数、千粒重、有效分蘖率进行了分析,结果表明剂量为2～4×1016N+/cm2处理对新疆春小麦适宜.     

Effect of alkaline pretreatment on delignification of wheat straw

This study was conducted to analyse structural changes through scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) after alkaline pretreatment of wheat straw for optimum steaming period. During the study, 2 mm size of substrate was soaked in 2.5% NaOH for 1 h at room temperature and then autoclaved at 121°C for various steaming time (30, 60, 90 and 120 min). Results revealed that residence time of 90 min at 121°C has strong effect on substrate, achieving a maximum cellulose content of 83%, delignification of 81% and hemicellulose content of 10.5%. Further SEM and FTIR spectroscopy confirmed structural modification caused by alkaline pretreatment in substrate. Maximum saccharification yield of 52.93% was achieved with 0.5% enzyme concentration using 2.5% substrate concentration for 8 h of incubation at 50°C. This result indicates that the above-mentioned pretreatment conditions create accessible areas for enzymatic hydrolysis.     

小麦茎秆的抗弯复合材料力学模型

为研究小麦茎秆的抗弯性能和获得茎秆材料常数,本文首先对小麦茎秆进行了四点弯曲的试验研究。在试验测量数据的基础上建立了小麦茎秆有限元计算模型,该模型考虑了植物材料的正交异性和管壁分层力学参数的变化等情况。本文还将Brazier屈曲理论引入小麦茎秆抗弯性能研究中,使用双层复合材料圆柱壳模型,分析得到了纯弯曲时小麦茎秆的曲率弯矩关系。研究结果表明:理论模型能够正确反映小麦茎秆的抗弯行为;局部屈曲是影响小麦茎秆的抗弯性能的重要因素;试验和有限元计算结果与理论解基本吻合。     

Der Einfluß des Zusatzes von Hemicellulosen auf die Fließeigenschaften von Weizenmehlteig

The water adsorption capacity of a dough consisting of wheat flour was increased linearly by the addition of water-insoluble hemicelluloses (xylane, mannane etc.) extracted from beech-wood pulp using soda lye (a by-product of viscose fiber production). The investigation of this finding by viscosity measurements revealed two reasons for the higher water uptake: 1) a higher kneading resistance of the dough, and 2) a gel-regeneration of the kneaded dough during the dough-rest.

Herrn Prof. Dr. Josef Schurz zum 60. Geburtstag gewidmet.     

Proteomic analysis of a spring wheat cultivar in response to prolonged cold stress

Cold represents one of the major abiotic factors influencing plant growth and development worldwide. We analysed the long-term responsiveness of an Iranian spring wheat (cv. Kohdasht) to cold from a proteomic point of view, in order to unravel the molecular mechanisms helping a cold-sensitive cultivar to survive exposure to suboptimal temperatures. Plants were grown at 20 or 4°C until entering the reproductive stage and a cross-comparison on the leaf proteomes was performed. Quantitative analyses on protein alterations occurring upon low-temperature exposure showed a reinforcement in ascorbate recycling (dehydroascorbate reductase, ascorbate peroxidase) and protein processing (proteasome subunit, cysteine proteinase), as well as the accumulation of the enzyme devoted to tetrapyrrole resynthesis (glutamate semialdehyde aminomutase). In contrast, among proteins down-regulated after cold stress, we could identify some key Krebs cycle enzymes (isocitrate dehydrogenase, malate dehydrogenase), together with many photosynthesis-related proteins (oxygen-evolving complex proteins, ATP synthase subunits, ferredoxin NADPH oxidoreductase and some Calvin cycle enzymes). Physiological and biochemical parameters (such as shoot apex dissection, chlorophyll, proline and sugar content determination) sustained proteomics findings allowing the present research to contribute to the current knowledge on these long-term responses, which may be crucial to stress adaptation under field conditions.     

基于遥感和作物生长模型的多尺度冬小麦估产研究

粮食安全是社会和谐、政治稳定和经济可持续发展的重要保障。准确预测区域乃至全球的农作物产量能够为各级政府、相关部门制定农业农村政策提供技术支持,保障粮食安全。目前关于农作物估产的研究大多具有地域性、经验性,过分依赖地面实测数据,一种基于多光谱卫星遥感数据和作物生长模型估算农作物产量的模型框架SCYM（Scalable Crop Yield Mapper）能够极大地减少模型对实测数据的依赖,快速应用于不同空间尺度、不同种类作物的估产,为多尺度农作物估产研究提供了一条有效的途径。以安徽省2012年-2018年冬小麦为研究对象,通过总结前人研究确定的敏感参数及其在研究区内的波动范围,结合大量实割实测数据优化WOFOST（WOrld FOod STudies）模型参数;将模拟产量、不同时段的模拟叶面积指数(LAI)同遴选出的天气变量训练随机森林模型,并以最佳观测日期组合下的MODIS-LAI代替对应时段的模拟LAI进行产量估算。结果表明：（1）模型产量估算值与站点实测值的总体相关性为0.758（R2为0.575）,RMSE为790.92 kg·ha-1。精度较高的站点主要分布在淮北平原（<1%）而高误差区域集中于皖南丘陵地带（>40%）;（2）对2012年-2018年全省范围进行冬小麦估产,根据7年平均估产结果的空间分布,小麦单产由北向南逐渐减少,高值区出现在皖北的淮北平原,低值区主要分布于皖中、皖南地区;（3）2012年-2018年实测单产平均值为6 058.00 kg·ha-1,SCYM估算单产平均值为5 984.95 kg·ha-1,且估算产量与实测产量的年际时间序列的相关性为0.822,RMSE为189.96 kg·ha-1,每年估产的相对误差均不超过6%。研究表明SCYM估产框架对安徽省冬小麦产量估算具有一定的可行性,在产量预报方面效果良好。该方法能够在一定程度上改善以往估产模型存在的地域性、经验性问题,在区域尺度的应用方面具有极大的潜力,未来可为农业估产提供极其重要的理论依据和实用价值。     

Mapping of powdery mildew using multi-spectral HJ-CCD image in Beijing suburban area

Powdery mildew is one of the most serious diseases, which has a significant impact on the production of winter wheat. As an effective alternative to traditional sampling methods, remote sensing can be a useful tool in disease detection. This study examines the potential of a moderate resolution multispectral satellite image in disease monitoring at regional scale. At the suburban area around Beijing, a large size ground survey sample (n = 90) and the corresponding HJ-CCD image were acquired at the grain filling stage of winter wheat. A number of spectral features were found to be sensitive to powdery mildew through an independent t-test. Based on these spectral features, classification models were established using both spectral information divergence (SID) and spectral angle mapper (SAM), respectively. The results showed that the overall accuracies of disease identification and severity estimation were moderate. The estimation of normal and seriously infected samples yielded higher accuracies than slightly infected samples. The single phase HJ-CCD can only be used for locating the infected areas of powdery mildew, whereas is unable to discriminate the severity levels of disease. The presence of several stressors and disturbances other than disease is a possible reason of the unsatisfactory performance of disease monitoring models. Therefore, the integration of multi-phase onboard data and some relevant ancillary data is necessary to improve the accuracy and reliability of disease monitoring at regional scale.