长江三峡地区干流河岸植物群落的初步研究

以长江三峡干流河岸植物群落为研究对象,对群落的物种组成、物种多样性进行了分析,并利用ＴＷＩＮＳＰＡＮ方法对植物群落进行高等级式划分。结果表明：河岸植物区系组成较为复杂,以温带成分为主,有着较高比率的世界分布成分。植物生活性方面,草本种类的比率略高于木本种类,藤本种类较少。藻、草丛群落之间的物种多样性差异不显著。ＴＷＩＮＳＰＡＮ和ＤＣＡ分析显示,河岸植物群藻可分为６大类群,这些类群呈现沿湿度梯度方向     

Molecular data and ecological niche modelling reveal the phylogeographic pattern of Cotinus coggygria (Anacardiaceae) in China's warm‐temperate zone

The phylogeography of common and widespread species helps to elucidate the history of local flora and vegetation. In this study, we selected Cotinus coggygria, a species widely distributed in China's warm‐temperate zone. One chloroplast DNA (cpDNA) region and ecological niche modelling were used to examine the phylogeographic pattern of C. coggygria. The cpDNA data revealed two phylogeographic groups (Southern and Northern) corresponding to the geographic regions. Divergence time analyses revealed that divergence of the two groups occurred at approximately 147,000 years before the present (BP), which coincided with the formation of the downstream area of the Yellow River, indicating that the Yellow River was a weak phylogeographic divide for C. coggygria. The molecular data and ecological niche modelling also indicated that C. coggyria did not experience population expansion after glaciations. This study thus supports the fact that Pleistocene glacial cycles only slightly affected C. coggygria, which survived in situ and occupied multiple localised glacial refugia during glaciations. This finding is contrary to the hypothesis of large‐scale range habitat contraction and retreat into a few main refugia.     

储藏方式和时间对三峡水库消落区一年生植物种子萌发的影响

为了明确不同储藏方式和储藏时间对三峡水库消落区4种1年生植物稗(Echinochloa crusgalli)、苍耳(Xanthium sibiricum)、合萌(Aeschynomene indica)和水蓼(Polygonum hydropiper)种子萌发能力的影响,筛选出有利于其萌发的最佳储藏方式及时间,采取5种储藏方式(室温、冷藏、冷冻、干沙、湿沙)、8个储藏时间段(30、60、90、120、150、180、210、240d)对种子进行储藏实验。在光照培养箱昼25℃/夜20℃和周期性光照(昼12h/夜12h,光强100μmol·m-·2s-1)条件下进行种子萌发,每次萌发持续时间为30d。结果显示:(1)稗、苍耳和水蓼的种子在湿沙储藏条件下萌发起始时间缩短,种子萌发率、萌发指数高于其它储藏方式;湿沙储藏条件下,稗的种子储藏90-180d萌发率达到80%以上,苍耳的种子储藏180d萌发率达(64±2)%,水蓼的种子储藏30-240d萌发率均超过90%。(2)冷冻储藏能有效地解除合萌种子休眠,显著提高其种子萌发率和发芽指数;冷冻储藏90-180d合萌的种子萌发率均超过80%,之间没有显著差异。(3)果皮是限制苍耳种子萌发的主要因素之一,而去除果皮对合萌种子萌发没有显著影响。研究结果建议:采用种子来进行消落区植被恢复和重建时,稗、苍耳和水蓼的最佳储藏方式是湿沙储藏,合萌的最佳储藏方式是冷冻储藏。结合三峡水库水位调度原则,在适宜的储藏方式下,本实验中储藏120-180d的种子能够应用于消落区实地播种中。     

山西省管涔山林区苔藓植物垂直带的研究

本文根据山西省管涔山林区苔藓植物特有种及优势种, 并参考环境特征, 将苔藓植物垂直带划分为:低山苔藓植物带, 针叶林区苔藓植物带、亚高山灌丛草甸区苔藓植物带。     

Distribution and biodiversity of rhizobia nodulating Chamaecrista mimosoides in the Shandong peninsula of china

Chamaecrista mimosoides is an annual herb legume widely distributed in tropical and subtropical Asia and Africa. It may have primitive and independently-evolved root nodule types but its rhizobia have not been systematically studied. Therefore, in order to learn the diversity and species affinity of its rhizobia, root nodules were sampled from C. mimosoides plants growing in seven geographical sites along the coast line of Shandong Peninsula, China. A total of 422 rhizobial isolates were obtained from nodules, and they were classified into 28 recA haplotypes. By using multilocus sequence analysis of the concatenated housekeeping genes dnaK, glnII, gyrB, recA and rpoB, the representative strains for these haplotypes were designated as eight defined and five candidate novel genospecies in the genus Bradyrhizobium. Bradyrhizobium elkanii and Bradyrhizobium ferriligni were predominant and universally distributed. The symbiotic genes nodC and nifH of the representative strains showed very similar topology in their phylogenetic trees indicating their co-evolution history. All the representative strains formed effective root nodules in nodulation tests. The correlation between genospecies and soil characteristics analyzed by CANOCO software indicated that available potassium (AK), organic carbon (OC) and available nitrogen (AN) in the soil samples were the main factors affecting the distribution of the symbionts involved in this current study. The study is the first systematic survey of Chamaecrista mimosoides-nodulating rhizobia, and it showed that Chamaecrista spp. were nodulated by bradyrhizobia in natural environments. In addition, the host spectrum of the corresponding rhizobial species was extended, and the study provided novel information on the biodiversity and biogeography of rhizobia.     

Flower colour variation across a hybrid zone in Antirrhinum as perceived by bumblebee pollinators

To assess if pollinators’ behaviour could explain the maintenance of hybrid zones between different flower colour morphs, we analyzed flower colour variation in an Antirrhinum hybrid zone using spectrometry and a model of bee perception. Some colours generated by hybridization were not observed in any Antirrhinum species and even appeared to be rare among angiosperms. Variation in flower colours within the hybrid zone was continuous; the most similar colours were predicted not to be discriminated from one another in natural foraging situations. However, when compared at a scale corresponding to bees’ foraging range, some flower colours could be discriminated from all colours displayed by neighbouring plants. This could affect pollinator behaviour and explain lower visitation rates within the centre of the hybrid zone. Behavioural studies involving bumblebees and plant mixtures of parental and hybrid flower colours carefully characterized with appropriate visual models will be necessary to test this hypothesis. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Handling editor: Lars Chittka     

A capillary zone electrophoresis method for the quantitative determination of hypoxoside in commercial formulations of African potato (Hypoxis hemerocallidea)

Hypoxoside is a norlignan diglucoside present in the corms of African potato, Hypoxis hemerocallidea, used as a popular African traditional medicine for its nutritional and immune boosting properties. A specific analytical method employing capillary zone electrophoresis has been developed and validated for the quantitative determination of this analyte. Sulfafurazole was used as internal standard, and electrophoretic separation of both analytes could be achieved within 12 min. Linearity of the method was established within the range 5-60 microg/mL and provided a high degree of accuracy (100 +/- 3%). The recovery of the method was found to be 100 +/- 5% and the RSDs of the intra- and inter-day precision were better than 5.19 and 2.52%, respectively. The limits of detection and quantification were calculated to be 0.5 and 2 microg/mL, respectively. The described method was used for the analysis and quality control of two commercially available products containing African potato. The method can also be used to determine product stability since it could separate the hypoxoside peak from its degraded products obtained from degradation studies.     

鳗鲡幼鱼耳石日轮的研究

本文报道采自辽东半岛沿岸鳗鲡(Anguilla japonica)的白仔鳗和经人工培育的当年幼鳗耳石日轮生长的观察结果。白仔鳗和幼鳗耳石平均直径均与体全长成直线相关。12尾白仔鳗耳石的平均日轮数146.3,据此推测其产卵期为11—12月。观察证实从咸淡水转人到淡水生活的幼鳗耳石的环纹有过渡带存在。     

Selection on outlier loci and their association with adaptive phenotypes in Littorina saxatilis contact zones

A fundamental issue in speciation research is to evaluate phenotypic variation and the genomics driving the evolution of reproductive isolation between sister taxa. Above all, hybrid zones are excellent study systems for researchers to examine the association of genetic differentiation, phenotypic variation and the strength of selection. We investigated two contact zones in the marine gastropod Littorina saxatilis and utilized landmark‐based geometric morphometric analysis together with amplified fragment length polymorphism (AFLP) markers to assess phenotypic and genomic divergence between ecotypes under divergent selection. From genetic markers, we calculated the cline width, linkage disequilibrium and the average effective selection on a locus. Additionally, we conducted an association analysis linking the outlier loci and phenotypic variation between ecotypes and show that a proportion of outlier loci are associated with key adaptive phenotypic traits.     

溪流潜流层大型无脊椎动物生态学研究进展

溪流潜流层是溪流表层水和地下水相互作用的群落交错区,生物多样性丰富,是溪流生态系统的重要组成部分.大型无脊椎动物位于潜流层食物网的顶层,直接影响着潜流层物质和能量动态,是河流健康潜在的指示生物,调节着潜流层的环境净化和生态缓冲功能,对溪流生态系统发挥着至关重要的作用.潜流层大型无脊椎动物类群按生活史划分为偶入动物、非典型潜流层动物和典型潜流层动物.潜流层孔隙大小、孔隙水流速、溶解氧、温度、可利用的食物源、渗透系数和水力停留时间是影响大型无脊椎动物在潜流层分布的主要因素.对于潜流层这样一个特殊的生态界面,针对不同的研究目的应该选择合适的取样和调查方法.潜流层大型无脊椎动物的生活史和生活史对策,在溪流生态系统物质循环和能量流动中作用的定量化分析,基于潜流层大型无脊椎动物的河流健康评价体系,以及潜流层作为“庇护地”对于大型无脊椎动物分布和进化的生态学意义,都值得进一步关注和深入研究.