Pollination of Habenaria tridactylites on the Canary Islands

We investigated the pollination of Habenaria tridactylites, an endemic orchid of the Canary Islands. The entirely green, widely open flowers have a long spur containing nectar. We carried out fieldwork, a molecular clock analysis, herbarium surveys, identified pollinators by both morphology and DNA barcoding, and measured the length of floral spurs and insect tongues using a combination of traditional and innovative micro‐CT scanning methods to 1) determine the pollinator of this orchid and 2) investigate correlations between local mean spur length and age, altitude and longitude of the island. Habenaria tridactylites was found to be pollinated on Tenerife by both small and intermediate sized moth species with variable tongue lengths and mostly belonging to Geometridae and to a lesser extent Crambidae, Erebidae, Noctuidae and Tortricidae. Of the sixteen moth species identified, nine are endemic to the Canary Islands or Macaronesia. The different local populations of H. tridactylites on the islands of Gran Canaria, El Hierro, La Gomera, La Palma and Tenerife with different ages and distances from mainland Africa, did not show a significant correlation of mean spur length and altitude, but did show a significant and positive linear correlation with longitude and the geological age of the island. The latter is congruent with the evolutionary arms race theory first proposed by Darwin, suggesting that flowers gradually evolve longer spurs and pollinators longer tongues.     

高通量扩增子测序分析生防细菌对丹参根际和根表土壤真菌群落多样性的影响

利用高量测序方法探究生防细菌对丹参植株根际和根表土壤真菌群落多样性的影响。

向丹参植株根部施入生防细菌DS-R5,培养45 d后采集根际和根表土壤样品提取总DNA,扩增样品基因组DNA的V4―V5区后进行双端测序,利用生物信息学解析生防细菌对丹参植株根际和根表土壤真菌群落多样性的影响。

菌株DS-R5处理后增加了根际和根表土壤真菌群落的多样性和丰度;根际土壤共有物种种类大于根表土壤,说明菌株DS-R5处理后根际土壤处理与对照物种种类更接近,而对根表土壤中的微生物物种影响较大。真菌群落结构组成分析结果表明,不同土壤样品在门水平上共有优势真菌主要有子囊菌门、接合菌门、担子菌门和未分类;相比根表土壤对照样品,根表土壤处理样品中子囊菌门丰度下降了13.0%,接合菌门丰度升高了69.2%;根际土壤处理样品相比根际土壤对照样品,子囊菌门和接合菌门丰度分别升高了5.9%和8.9%,但二者差异无统计学意义。在属水平上,根表土壤样品经菌株DS-R5处理后提高了有益菌属的丰度,同时降低了有害菌属的丰度。

丹参植株施入生防细菌后,改变了根际土壤和根表土壤中微生物群落结构和多样性,本研究结果可以为利用生防细菌防控丹参根腐病提供理论参考。

     

草地贪夜蛾对不同品种玉米的适应性比较研究

为了解不同玉米品种对草地贪夜蛾生长发育的影响,本文通过比较草地贪夜蛾Spodoptera frugiperda取食2种糯质型玉米(明玉1203和苏玉糯5号)与3种普通玉米(苏玉29、苏玉30和郑单958)后的发育历期、死亡率、蛹重、成虫畸形率、繁殖力与幼虫取食选择率等生物学参数,分析了草地贪夜蛾对不同品种玉米的适应性差...     

Effects of Water Stress and Abscisic Acid on Transpiration Regulation in Wheat

The transpiration response to recurrent light periods was studied'n water-stressed wheat seedlings. Seedlings were stressed by three methods: addition of mannitol to the root medium, root cooling and drving of the roots in air. All three methods induced almost equal effects on transpiration regulation during alternating dark and light intervals. Exogenous abscisic acid supplied to the shoots of excised plants had qualitatively the same effect as water stress. Water stress and ABA increased the time lapse between light-on and the onset of transpiration increase and lowered the amplitude of transpiration increase in light. Weak light introduced before strong light shortened the delay times.     

Persistent Topology and Metastable State in Conformational Dynamics

The large amount of molecular dynamics simulation data produced by modern computational models brings big opportunities and challenges to researchers. Clustering algorithms play an important role in understanding biomolecular kinetics from the simulation data, especially under the Markov state model framework. However, the ruggedness of the free energy landscape in a biomolecular system makes common clustering algorithms very sensitive to perturbations of the data. Here, we introduce a data-exploratory tool which provides an overview of the clustering structure under different parameters. The proposed Multi-Persistent Clustering analysis combines insights from recent studies on the dynamics of systems with dominant metastable states with the concept of multi-dimensional persistence in computational topology. We propose to explore the clustering structure of the data based on its persistence on scale and density. The analysis provides a systematic way to discover clusters that are robust to perturbations of the data. The dominant states of the system can be chosen with confidence. For the clusters on the borderline, the user can choose to do more simulation or make a decision based on their structural characteristics. Furthermore, our multi-resolution analysis gives users information about the relative potential of the clusters and their hierarchical relationship. The effectiveness of the proposed method is illustrated in three biomolecules: alanine dipeptide, Villin headpiece, and the FiP35 WW domain.     

两个苜蓿品种营养器官解剖结构特征比较

为了明确具有极强抗虫特性的‘草原4号紫花苜蓿’(Medicago sativa L.‘Caoyuan No.4’) 营养器官的解剖特征,该研究选择具有抗蓟马特性较强的‘草原2号杂花苜蓿’(Medicago varia Martin.‘Caoyuan No.2’)为对照,采用显微镜观察比较两品种的根、茎、叶解剖结构特征,为揭示‘草原4号紫花苜蓿’ 抗蓟马特性提供理论依据。结果显示：(1)‘草原4号紫花苜蓿’根部解剖结构的皮层薄壁细胞厚度、内皮层厚度、形成层厚度、木质部厚度和木射线宽度等5个指标均极显著高于(P＜0.01)‘草原2号杂花苜蓿’,其中木射线宽度(159.37 μm)是‘草原2号杂花苜蓿’的1.82倍。(2)‘草原4号紫花苜蓿’的茎部厚角组织厚度(21.4 μm)极显著高于‘草原2号杂花苜蓿’(P＜0.01),而韧皮部宽度、髓直径却均极显著低于‘草原2号杂花苜蓿’(P＜0.01)。(3)‘草原4号紫花苜蓿’叶片解剖构造的7个指标均极显著高于‘草原2号杂花苜蓿’(P＜0.01),其中栅栏组织层数(2～3层)极明显地高于‘草原2号杂花苜蓿’(1~2层)。研究表明,‘草原4号紫花苜蓿’的组织结构特征具有明显的抗虫特征,且其组织的抗虫特征比‘草原2号杂花苜蓿’更为突出。     

Palaeoenvironmental aspects of Late Ordovician Sericoidea shell concentrations in an impact crater,Tvären,Sweden

Frisk, Å.M. & Harper, D.A.T. 2010: Palaeoenvironmental aspects of Late Ordovician Sericoidea shell concentrations in an impact crater, Tvären, Sweden. Lethaia, Vol. 44, pp. 383–396. Numerous studies have reported the presence of the small, thin‐shelled cosmopolitan rhynchonelliformean Sericoidea as being environmentally controlled and, together with its close relatives, characteristic of deep‐water, distal, clastic Ordovician and Silurian settings. Assemblages of Sericoidea have been analysed from post‐impact strata in a newly formed Late Ordovician impact crater. In the crater succession, colonization of benthic faunas can be monitored through the post‐impact limestone, demonstrating a number of environmental preferences. Consequently, the crater, as a result of its restricted area, provides an experimental arena for faunal distributions to be correlated with specific environments. The continuous infilling of the crater following its formation reveals a transition from argillaceous mudstones to carbonates deposited in deeper‐water environments to shallower regimes. Rhynchonelliformean brachiopods inhabited the crater depression very late after the impact and are entirely represented by the genus Sericoidea, occurring abundantly in the upper third of the existing crater infill. The deep‐water regime that existed in the depression during the initial interval of crater formation had been substantially reduced. Clearly Sericoidea‐bearing associations associated with shaly substrates did not merely favour and occupy deep‐water environments as previously suggested. The unfavourable conditions triggered by the impact and the inhospitable aftermath allowed Sericoidea to exploit a less‐crowded ecospace. This reorganization, following the catastrophe, from a deep‐water related ecological niche to considerable shallower settings suggests that Sericoidea was a pioneer colonist displaying an opportunist r‐strategy. The shell beds analysed are related to shallower water and this may, moreover, help unravel the dilemma of the general absence of Sericoidea in the deeper‐water Foliomena fauna. □Dalby Limestone, impact crater, Late Ordovician, opportunists, Sericoidea, Tvären.     

里约热内卢2016奥林匹克公园总体规划

里约热内卢是一个自然城市,她是城市发展和原生自然成功融合的产物。2016年奥运会和残奥会公园的规划场地位于Tijuca和Pedra