三角梅苞叶色彩参数和色素含量分析及蓝色转基因受体的筛选北大核心CSCD

三角梅作为重要的观赏植物颜色繁多,但缺乏稀有的蓝色。为筛选适合的蓝色转基因受体,明确不同品种三角梅苞片吸收利用DHM(二氢杨梅素)合成甜菜色素途径竞争产物(类黄酮色素)的潜在能力,该研究对红色、白色、黄色和紫色4大花色6个品种的三角梅苞片进行离体诱导培养,测定诱导培养后苞片色彩参数及色素含量变化,并进行相关性分析。结果显示:(1)三角梅苞片红绿色相值(a*)是决定苞片呈色的主要色彩参数,其色彩主要由甜菜色素和黄酮类色素决定,并以甜菜红素的影响最大。(2)除白色品种三角梅苞片中黄酮类色素含量大于甜菜色素含量外,其余品种苞片发育中甜菜色素含量均呈上升趋势,黄酮类色素呈下降趋势。(3)甜菜色苷含量与苞片a*值呈显著正相关关系,同时与苞片黄蓝色相值(b*)呈显著负相关关系;总黄酮含量与苞片b*值呈显著正相关关系,与苞片a*值呈极显著负相关关系。(4)经DHM体外诱导培养后,苞片总黄酮含量及占比在4个品种三角梅(‘新加坡大白’、‘宝老橙’、‘中国丽人’、‘黄蝶’)中明显升高,但各品种苞片总甜菜色素含量及占比均下降,并以‘新加坡大白’苞片中总黄酮含量上升幅度最大(65.77%),含量占比变化(增加26.91%)也为6个品种中最大。(5)灰色关联度综合分析显示,白色品种‘新加坡大白’与灰色关联度分析拟定的参考品种关联度最高(0.7444),表明三角梅品种中‘新加坡大白’可考虑作为蓝色转基因三角梅的受体品种。     

自然保护区管理中生态与娱乐属性的权衡:一个选择实验的应用

随着自然保护区多样化的发展以及旅游需求的日益增长,保护区管理者面临着保护生态环境与满足娱乐需求的双重压力,这使得保护区管理者需要更多的信息进行决策。以中国东北部的扎龙国家级自然保护区为例,进行了一项选择实验,选取生物多样性、预期游客数量、景区的环境教育设施、门票价格等4个属性,分别采用多项logit模型、随机参数logit模型和潜在分类模型,探究游客在可能存在冲突的管理优先级之间的偏好。目的是揭示游客如何评价保护区不同的管理属性,以及各属性的边际支付意愿和偏好,并根据这些信息制定有效的保护区管理指南。研究结果表明生物多样性是保护区游客最关注的属性,并且游客对于生态属性的关注度高于娱乐属性。因此,保护区管理者应首先维持并改善生物多样性及其生态环境,在不破坏生态环境的基础上开发具有环境教育作用的娱乐服务。此外,研究发现游客可分为生态友好型和价格敏感型两种类别,不同类型的群体对游览保护区存在不同偏好,女性和年轻的受访者对生态更友好,男性和年长的受访者对价格更敏感。本文的贡献是将某一方面属性价值的描述扩展到涵盖多个管理属性的研究,并为保护区管理中生态与娱乐的权衡问题提供了更具体的见解。     

产胞外布雷菲德菌素A青霉发酵条件的研究

通过正交设计试验,优化了青霉(Penicillium)属真菌SHZK-15产胞外布雷菲德菌素(B refeld in-A,简称BFA)的液体发酵条件。最佳的BFA发酵条件为:培养基含马铃薯200g(煮汁),葡萄糖20g,(NH4)2SO44.0g,KH2PO41.0g,MgSO4.7H2O 2.0g,CaCO35.0g,pH自然,瓶装量为100mL/250 mL,培养温度为28℃,转速为120 r/m in,培养时间为7d,BFA的最高产量可达151.6mg/L。     

短毛柽柳不同部位中总黄酮含量及稳定性研究

目的：比较短毛柽柳中不同部位总黄酮的含量差异,研究黄酮化合物保存的条件,方法：采用超声波乙醇浸提法,在正交优先的最佳条件（料液比为1∶15,超声处理时间为40min,乙醇浓度为45%,超声温度50℃,提取3次）下提取不同部位总黄酮,并测定不同条件下其吸光度的变化。结果：柽柳花、叶、茎中总黄酮得率分别为24.585mg/g、25.623mg/g、41.726mg/g,柽柳中提取的黄酮溶液在光照、高温、高浓度蔗糖溶液和Na＋存在条件下不稳定;pH 4~7条件下较稳定;氧化剂对其稳定性的影响不大。结论：柽柳茎中总黄酮含量明显高于其他两个部位。柽柳黄酮保存时应避免接触碳水化合物和盐离子,在避光、常温、中性条件下保存。     

兴安落叶松叶碳利用效率对环境变化的适应

兴安落叶松(Larix gmelinii)作为北方森林的主要组成树种,具有广阔的分布范围和多样的生长环境,是研究树木对环境变化响应的理想树种。叶碳利用效率(CUE_L)不仅与树木的碳代谢及生长发育密切相关,而且能反映树木对环境变化的响应与适应。将来自不同地区(即环境条件)的6个兴安落叶松种源的种子播种培育在帽儿山森林生态系统研究站内,在其生长30a后采用研究站和种子来源地间干燥度(AI)的差值(ΔAI)来代表环境变化梯度,研究环境变化对CUE_L的影响。结果表明:CUE_L在不同环境变化梯度间存在显著差异(P0.05),且呈现随ΔAI的增大而减小的趋势。CUE_L与叶片氮含量、叶片磷含量、比叶重及叶绿素含量等均呈线性正相关关系,但较大ΔAI梯度下的CUE_L敏感性更高。CUE_L与种子来源地平均年降水量呈显著线性正相关关系(P=0.05),而与种子来源地AI则呈显著线性负相关关系(P0.01);随种子来源地年平均气温、平均年蒸发量的增加而下降,但其相关性不显著。以上结果表明,环境变化使兴安落叶松CUE_L产生了适应性变异,表现出树木对原生长环境的生态适应。     

Predicting plant invasions under climate change: are species distribution models validated by field trials?

Climate change may facilitate alien species invasion into new areas, particularly for species from warm native ranges introduced into areas currently marginal for temperature. Although conclusions from modelling approaches and experimental studies are generally similar, combining the two approaches has rarely occurred. The aim of this study was to validate species distribution models by conducting field trials in sites of differing suitability as predicted by the models, thus increasing confidence in their ability to assess invasion risk. Three recently naturalized alien plants in New Zealand were used as study species (Archontophoenix cunninghamiana, Psidium guajava and Schefflera actinophylla): they originate from warm native ranges, are woody bird‐dispersed species and of concern as potential weeds. Seedlings were grown in six sites across the country, differing both in climate and suitability (as predicted by the species distribution models). Seedling growth and survival were recorded over two summers and one or two winter seasons, and temperature and precipitation were monitored hourly at each site. Additionally, alien seedling performances were compared to those of closely related native species (Rhopalostylis sapida, Lophomyrtus bullata and Schefflera digitata). Furthermore, half of the seedlings were sprayed with pesticide, to investigate whether enemy release may influence performance. The results showed large differences in growth and survival of the alien species among the six sites. In the more suitable sites, performance was frequently higher compared to the native species. Leaf damage from invertebrate herbivory was low for both alien and native seedlings, with little evidence that the alien species should have an advantage over the native species because of enemy release. Correlations between performance in the field and predicted suitability of species distribution models were generally high. The projected increase in minimum temperature and reduced frosts with climate change may provide more suitable habitats and enable the spread of these species.     

Response of deposit-feeders to exclusion of epibenthic predators in a Mediterranean intertidal flat

Deposit-feeders are common components of macrofaunal assemblages in intertidal soft sediments. Predation has been considered to have a central role in affecting their distribution and population dynamics. This study investigates the effect of epibenthic predators on deposit-feeders, inhabiting the shallow layers of the sediment (surface and subsurface) and also the deepest layers (e.g., burrowing shrimp Upogebia pusilla; Petagna). The experiment was conducted in summer 2000 (August-September) at three different sites on an intertidal flat in Mediterranean Sea. In the field, predators were excluded using cages, placed on the surface of the sediment. It was predicted that under the cages, (i) abundances of animals would increase and (ii) species composition of assemblages would change as an effect of the exclusion of predators. Potential artefacts caused by the cages were controlled using partial cages (PC). Composition of organic matter and porosity were also analysed under PC and in natural controls to test whether the presence of cages would change sediment characteristics on the surface. At the end of the experiment, there were no significant differences in the composition of organic matter between PC and the undisturbed sediment (UC). After 8 weeks from the beginning of the experiment, exclusion of predators enhanced the abundance of U. pusilla. There were, however, no clear-cut changes in the species composition of macrofaunal assemblages and densities of animals did not increase under the cages. Indeed, some animals (Oligochaeta, Brania oculata, and Tanais dulongii) were less abundant under the cages (EC) than outside (PC and UC). We propose that predation might play a role in regulating interspecific relationships among some surface deposit-feeders and the burrowing shrimp U. pusilla.     

矮珍珠硝酸盐转运蛋白基因GeNRT2.1的克隆和功能研究

硝酸盐转运蛋白（nitrate transporter,NRT）是植物识别、吸收和转运硝酸盐的关键蛋白,对促进作物根系发育、提高产量具有重要作用。通过筛选水生植物,利用NRT蛋白的保守区设计简并引物,并通过PCR和RACE技术,首次从矮珍珠（Glossostigma elatinoides）中克隆得到GeNRT2.1基因。进化分析结果表明,GeNRT2.1与烟草NRT2.1在进化关系上距离最近。qRT-PCR结果表明,GeNRT2.1在矮珍珠根中表达量最高,其次是叶和茎,此外,低浓度硝酸盐（0.5 mmol·L^-1）处理后,GeNRT2.1在根、叶、茎中的表达量分别是高浓度硝酸（2 mmol·L^-1）处理后的1.89、1.93和2.07倍。功能互补实验发现,GeNRT2.1能使缺陷型酵母Δynr恢复生长,具有硝酸盐转运蛋白的功能。通过丰富NRT基因资源,以期为培育氮肥高效利用转基因作物,发展绿色农业,保证我国的粮食安全和环境安全提供理论依据。     

Enhancing students’ experimental planning competences by introducing and evaluating the IS4O teaching approach

ABSTRACT

We herein report the introduction of the IS⁴O (Improving Students’ Scientific Skills by Using Scaffolding Outlines) teaching approach and its implementation to successfully empower students with initial minor planning competences in mastering complex scientific challenges in the course of Germany’s most-renowned scientific competitions. The IS⁴O teaching approach itself comprises the unique combination of the differentiating teaching methods Backward Planning and Project Mapping as core teaching elements. The beneficial effect of the IS⁴O teaching approach on the enhancement of the students planning competences is also discussed. Based on the given results, this teaching approach is mandatory to empower students with initial minor competences in completing a scientific competition successfully with very high assignment of tasks.