桃潜叶蛾在桃园的空间分布型和取样技术研究

应用聚集度指标法、Iwao回归分析和频次比较法．研究了桃树重要害虫桃潜叶蛾成虫的空间分布型。结果表明桃潜叶蛾成虫在桃园呈负二项分布,分析提出了该害虫适宜的调查抽样方法。     

Spatial distribution characteristics of stomata at the areole level in Michelia cavaleriei var. platypetala (Magnoliaceae)

Background and AimsIn hierarchically reticulate venation patterns, smaller orders of veins form areoles in which stomata are located. This study aimed to quantify the spatial relationship among stomata at the areole level.MethodsFor each of 12 leaves of M. cavaleriei var. platypetala, we assumed that stomatal characteristics were symmetrical on either side of the midrib, and divided the leaf surface on one side of the midrib into six layers equidistantly spaced along the apical–basal axis. We then further divided each layer into three positions equidistantly spaced from midrib to leaf margin, resulting in a total of 18 sampling locations. In addition, for 60 leaves, we sampled three positions from midrib to margin within only the widest layer of the leaf. Stomatal density and mean nearest neighbour distance (MNND) were calculated for each section. A replicated spatial point pattern approach quantified stomatal spatial relationships at different distances (0–300 μm).Key ResultsA tendency towards regular arrangement (inhibition as opposed to attraction or clustering) was observed between stomatal centres at distances <100 μm. Leaf layer (leaf length dimension) had no significant effect on local stomatal density, MNND or the spatial distribution characteristics of stomatal centres. In addition, we did not find greater inhibition at the centre of areoles, and in positions farther from the midrib.ConclusionsSpatial inhibition might be caused by the one-cell-spacing rule, resulting in more regular arrangement of stomata, and it was found to exist at distances up to ~100 μm. This work implies that leaf hydraulic architecture, consisting of both vascular and mesophyll properties, is sufficient to prevent important spatial variability in water supply at the areole level.     

Influences of Woody Debris on Flow Patterns and Channel Morphology in a Low Energy,Sand‐Bed Stream Reach

In lowland areas, such as the glacial landscapes of eastern Germany, sand‐bed streams are the most common stream type. They have low gradients and their hydrological regime is often subdued due to the frequent interruption by lakes. Very few is known about the influence of woody debris in these streams, since nearly all previous studies are from high‐gradient conditions, where streams have coarse bed sediments and harsh hydrological regimes. The research objectives of this study were first to assess the quasi‐natural quantity and quality of wood in a lowland sand‐bed stream and second to understand the influence of wood on the channel morphology and the flow patterns at base‐flow. The three‐dimensional stream bed relief was surveyed by electronic distance measurement. The position and the size of large woody debris was assessed by close‐up photography. An acoustic Doppler velocimeter was used to record the patterns of flow velocity and turbulence. Overlay and analysis of the spatial data was done using a Geographic Information System. The standing stock of wood was 1.9 m³ and 39 woody elements per 100 m² of stream bed. The flow pattern was clearly controlled by the wood. Woody elements elevated above the stream bed deflected flow and locally caused strong secondary current, high turbulence, and scour of the stream bed at baseflow. Wood resting directly on the stream bed, which contributed the majority of the wood inside the bank‐full channel, determined the roughness of the stream bed. Near‐bed flow patterns observed were isolated roughness flow and wake interference flow, which was registered inside the accumulations of wood. 68% of the stream bed had shear stress above critical. Hence, the secondary morphological structures of the sand‐bed were controlled at base‐flow by the flow which was determined by the woody debris distribution.     

Assessing spatial patterns and density of a dolphin population through signature whistles

Some dolphin species produce signature whistles, which may allow the identification of individual dolphins using passive acoustic monitoring (PAM). Identifying individuals by their sounds may enhance the opportunities for monitoring and addressing biological and ecological questions about these species. Here, we explored the potential of signature whistles to investigate ecological aspects of a resident bottlenose dolphin population. Using a limited data set, with few individuals recognized by signature whistles, combined with spatial capture-recapture (SCR) methods, we investigated how effective such approach is describing spatial use patterns and estimating density for this population. The data were collected using 4–6 stationary bottom-moored recorders. Since only eight signature whistles were identified, our density estimate may represent a subset of the entire population. However, even with only a few signature whistles identified, our results confirmed the center of the core area used by these dolphins as the area with the highest encounter probability. In addition, our results provided evidence that these dolphins have the same spatial use pattern at night as during the day. This study shows that SCR analysis of signature whistle data can improve our ecological knowledge and understanding of dolphin populations.     

无噪声Hodgkin-Huxley神经元对正弦信号的响应

研究了无噪声影响下的Hcdgkin-Huxley神经元在正弦信号刺激下的动力学行为,并利用“魔梯”图和峰峰间期分布图来分别描述。数值模拟结果表明,当信号振幅一定时,神经元的发放情况随频率而改变;当信号的频率一定时,峰峰间期分布随振幅而改变,相应地,峰峰间期序列也具有不同的特点。     

烟草甲细胞色素P450还原酶基因的分子特征与表达模式分析

烟草甲Lasioderma serricorne是一种重要的仓储害虫,长期化学防治导致烟草甲已对多种传统熏蒸剂产生抗性,但其对新型熏蒸剂甲酸乙酯仍处于敏感水平。因此明确其体内细胞色素P450还原酶（cytochrome P450 reductase, CPR）对甲酸乙酯的代谢解毒功能,对开展该药剂的抗性监测及延缓抗性的发生发展具有重要意义。本研究旨在克隆烟草甲LsCPR基因,分析其分子特征和表达特性,为进一步明确其在烟草甲对甲酸乙酯解毒代谢过程中的作用奠定基础。利用RT-PCR技术克隆烟草甲LsCPR基因的开放阅读框（open reading frame, ORF）;利用生物信息学软件分析LsCPR编码蛋白的结构、特征和系统进化关系。采用实时定量PCR技术检测LsCPR在烟草甲不同发育阶段（低龄幼虫、高龄幼虫、蛹、低龄成虫、高龄成虫）、幼虫不同组织（表皮、肠道、脂肪体和马氏管）以及甲酸乙酯熏蒸胁迫后的表达模式。烟草甲LsCPR基因的ORF为2 046 bp（GenBank登录号：MZ423209）,编码681个氨基酸,具有典型的昆虫CPR基因FMN区域、NADPH区域和FAD等保守结构域。系统发育分析表明,烟草甲LsCPR与鞘翅目昆虫聚为一支,且与赤拟谷盗Tribolium castaneum CPR亲缘关系最近。LsCPR在烟草甲不同发育阶段均有表达,在高龄幼虫期的表达水平较高;在幼虫体内的表达部位主要在肠道,其次为脂肪体和马氏管,而在表皮的表达水平最低。LC10、LC30和LC50 3种浓度的甲酸乙酯处理24 h后,烟草甲LsCPR表达量随着胁迫浓度升高而上调且显著高于对照;甲酸乙酯LC50处理烟草甲不同时间（3、6、12、24和48 h）后,LsCPR基因上调表达,24 h时达到表达高峰。推测LsCPR是参与烟草甲代谢甲酸乙酯的候选基因。     

管氏肿腿蜂毒液过敏原3基因的克隆及表达分析

为研究管氏肿腿蜂Scleroderma guani毒液过敏原3基因SgA3的功能,通过RT-PCR克隆SgA3基因,采用荧光定量PCR分析其在不同发育阶段和组织中的表达特征,并利用载体pSUMO-Mut对其进行原核表达。克隆获得SgA3基因开放阅读框长699 bp,编码233个氨基酸,其中信号肽位于N端第1~23位氨基酸。多序列比对分析发现,SgA3与丽蝇蛹集金小蜂Nasonia vitripennis、粉蝶盘绒茧蜂Cotesia glomerata、红火蚁Solenopsis invicta和常见黄胡蜂Vespula vulgaris过敏原3的氨基酸序列一致性分别为50.44%、50%、48.89%和47.83%。荧光定量PCR结果表明,SgA3基因在雌成虫中高表达,且在毒液器官中的表达量显著高于雌成虫其他组织和雄成虫中的表达量。利用pSUMO-Mut表达载体,成功表达并纯化得到高纯度的SgA3重组蛋白。该研究结果为进一步研究SgA3基因的功能奠定了基础。     

Flow Pattern and Mixing in the Multi‐Turbine Agitated Bioreactor Filled with Poly(γ‐Glutamic Acid) Solution

We investigated the flow pattern and mixing behavior of a poly(γ‐glutamic acid) (γ‐PGA) solution in a bioreactor equipped with two Rushton turbines by simulation and experiment. Computational fluid dynamics (CFD) is used to solve the three‐dimensional hydrodynamics in the bioreactor and to obtain the flow patterns and tracer concentration at every point. The flow circulation patterns by inter‐impeller clearance and viscosity and their effects on overall mixing time were studied. Based on the results we can conclude that the impeller clearance should not be larger than 0.2 D for the efficient mixing under non‐aerated condition when the liquid viscosity is above 20 cp, which corresponds to concentrations of 20 g/L or above for γ‐PGA.