基于茎直径微变化的梨枣灌溉指标的初步研究

 研究了4年生酸枣砧梨枣（Ziziphus jujuba Mill.）植株主干茎直径微变化指标对土壤水势（SWP）变化的响应规律,以及与气象要素的关系。结果表明：土壤水势降低引起茎直径日最大收缩量（MDS）增大,日生长量（DG）、生长速率（TGR）和日最大值（MXTD）降低。在水分亏缺发展阶段和水分亏缺维持阶段,MDS和TGR的噪声信号（变异系数）较小,信号强度与噪声信号的比值较大,表明其对土壤水势变化反映敏感。此外,MDS、TGR与潜在蒸散量（ET₀）、正午水汽压亏缺（VPD_md）等气象因子的相关性显著,均能反映大气的干旱程度,因此TGR和MDS可作为梨枣水分亏缺的诊断指标。     

热烫漂洗对鲜食草莓品质的影响

以“丰香”草莓为材料 ,采取水浴热烫方法 ,研究了不同温度处理对草莓品质的影响。结果表明 :草莓是典型的热敏性果类 ,随热烫温度上升 ,其外观品质和营养品质均呈下降趋势。除受温度影响外 ,草莓过氧化物酶 (POD)相当耐热 ,温度升高 ,其活性增加 ,并在高温时保持较高活性 ,成为破坏草莓品质的重要因素。综合生化指标检测和感官评判结果 ,热烫漂洗草莓在 60℃不宜超过 10min。     

提升小波变换及其在信号去噪中的应用

介绍了提升方法(1ifting Scheme)的基本原理,给出了用提升方法构造传统小波的实现方法,并将目前常用的小波转换成提升小波。同时还将提升小波应用到信号去噪中,并进行了数值仿真试验,结果表明,在去噪后信号的信噪比相近的情况下,提升小波与传统小波相比,其优点在于计算简单、编程容易、速度快。     

逆境下植物电信号研究现状与发展趋势

植物电信号是参与植物体内生理调控和传送信息的重要生理信号,其变化是植物对外界环境刺激的快速响应,而逆境刺激一旦超出植物承受范围,便无法通过自身修复。因此,通过对逆境下植物电信号变化进行深入研究,可依据不同环境胁迫和激励植物电信号的综合分析建立相关模型,以探究植物的最适生长环境特征。本文基于目前的相关研究文献资料,对植物电信号及其对逆境反馈的研究现状进行了梳理归纳,并在现有技术基础上对其发展趋势进行展望,以期为科研人员深入研究植物电信号提供参考,进而为推动植物育种和高产优质种植业高质量发展提供科学依据。     

UV-B辐射对小麦幼苗光信号通路的影响

为了解UV-B辐射对小麦光信号转导通路的影响,以冬小麦品种晋麦8号为材料,对不同UV-B剂量（10、12和14 kJ·m^-2·d^-1）辐射处理的小麦幼苗分别施用钙调蛋白（CaM）拮抗剂、G蛋白激活剂、Ca²⁺拮抗剂、丝氨酸/苏氨酸蛋白激酶拮抗剂,分析了光信号通路各组分的变化。结果表明,（1）CaM、G蛋白、Ca²⁺、丝氨酸/苏氨酸蛋白激酶和花色素苷参与了UV-B辐射诱导的小麦光信号通路的传导;（2）低剂量和高剂量的UV-B辐射对花色素苷含量的调控不是通过同一条信号通路;（3）UV-B辐射强度为10和12 kJ·m^-2·d^-1时,会诱导查尔酮合酶（CHS）基因的表达,而14 kJ·m^-2·d^-1UV-B辐射强度会抑制CHS基因的表达。说明UV-B辐射影响植物生理生化的信号通路因辐射剂量而异。     

拖拉机发动机电气故障诊断方法研究——基于信号瞬态成分稀疏表示方法

由于拖拉机发动机工作时的噪声较大,其故障信号较难采集,而电气信号的输出较为平稳,因此可以通过电气信号的特征提取来诊断发动机的故障。发动机电气的故障信号一般是特征较为明显的瞬态信号,有多种检测方法,信号的特征不同,各种方法的检测性能也会存在差异。本次提出了一种基于小波和稀疏表示的瞬态信号检测方法,并搭建了虚拟仪器平台对发动机的故障信号进行了检测。结果表明:采用小波和信号成分稀疏表示可以成功地提取发动机电气故障的瞬态信号特征,然后将信号特征和经验特征进行比对,便可以判断发动机电气的故障类型,为拖拉机发动机故障诊断的研究提供了重要的数据参考。     

Manipulation of plant methylglyoxal metabolic and signaling pathways for improving tolerance to drought stress

Drought stress is considered one of the major constraints to crop production with devastating effects worldwide. Methylglyoxal (MG) homeostasis plays an essential role in promoting plant growth, development, metabolic adaptation, signal transduction, and thereby responses to drought stress. Manipulation of genes encoding aldose-aldehyde reductases (ALRs), aldo– keto reductases (AKRs), genes that are involved in maintaining high ascorbate:glutathione (AsA:GSH), glutathione:glutathione disulfide (GSH:GSSG) contents and ratios, as well as jasmonic acid (JA) biosynthesis are of critical importance for improving MG detoxification, and thereby tolerance to drought stress. MG detoxification by maintaining optimal abscisic acid (ABA), JA, salicyclic acid (SA), and brassinosteroid (BR) homeostasis and crosstalk is also essential to optimize plant performance under both normal and drought stress conditions.     

基于三温模型和热红外遥感的不同大豆品种蒸腾特征研究

蒸腾耗水是水循环中重要的水分存在形式之一,是准确量化水分利用效率的关键参数,对研究碳水循环关系及节水农业有重要意义。本研究以大豆品种‘晋21’(J21)和‘Union’(C08)为研究对象,设置两种水分处理[当地经验灌水定额的75%(A0)和37.5%(A1)],基于三温模型(3TModel)和热红外遥感,定量研究不同品种和不同水分胁迫下的大豆蒸腾速率,揭示其时空特征差异,从而为抗旱节水大豆品种筛选提供参考。研究结果表明:1)不同处理下大豆的蒸腾速率日变化趋势与气温、太阳净辐射和冠层温度的基本一致,呈先增加后减小的单峰曲线,且于午间达到峰值,峰值为1.2～2.5mm·h~(-1);各处理的大豆冠层温度和蒸腾速率均呈现出明显的空间异质性。2)J21与C08大豆的冠层温度A0处理分别低于A1处理6.55K和5.91K,蒸腾速率A0处理高于A1处理0.28 mm·h~(-1)和0.29 mm·h~(-1);大豆蒸腾速率与灌水量呈正相关、与冠层温度呈负相关。3)在相同水分胁迫下,大豆冠层温度J21低于C08 1.83～2.47 K,蒸腾速率J21高于C08 0.13～0.14 mm·h~(-1)。本研究与传统方法相比,所需要的参数较少,避开了空气动力学阻抗等难获取的参数,对农田尺度更具有适宜性,更能揭示不同农田环境下作物的蒸腾时空异质性,在农业水分高效利用和节水品种筛选上有十分重要的科学意义。     

Non-stationary thermal time accumulation reduces the predictability of climate change effects on agriculture

Current modeling studies on the impacts of climate change on agriculture widely assume that thermal time accumulation of crops during the growing season remains constant under various climate conditions. However, in this study, a 20-year single rice variety, experimental dataset indicates that the thermal time accumulation for the entire growing season is not constant. As a result, a crop model based on constant thermal time accumulation significantly underestimates the observed phenological trend exhibited over the two decades of research—despite comparably accurate simulations of short periods. This deviation can result in misleading yield simulations, whereas the model simulations, using observed phenology data, show a similar yield trend as the observation. This study casts serious doubt on the assumptions of constant thermal time accumulation made in previous modeling studies, and, moreover, it highlights the critical requirements needed to improve phenology simulations on a larger scale so that predictions of the eventual yield trends due to climate change can more accurately reflect the results of yield trends in reality.     

The severity of smouldering peat fires and damage to the forest soil

Smouldering wildfires propagate slowly through surface and subsurface organic layers of the forest ground and severely affect the soil, producing physical, chemical and biological changes. These effects are caused by the prolonged heating and the large loss of soil mass but are poorly documented in the literature. A series of smouldering experiments with boreal peat have been conducted under laboratory conditions to quantify these effects using small-scale samples. Peat samples of 100 mm by 100 mm in cross section and 50 mm in depth of different moisture were exposed to an external ignition source. Thermocouples placed throughout the sample bed measured the temperature evolution and tracked the peat ignition, intensity and spread of the smouldering front. The results show that moisture content controls peat ignition and that moisture below 125 ± 10% (in dry base) are required. The severity of the smouldering peat on the soil has been quantified in terms of temperature vs. residence time curves and mass loss. The measurements show temperatures in excess of 300 °C for residence times of 1 h leading to sterilization of the soil and mass loss in burnt layers above 90%.