A new,three‐dimensionally preserved enantiornithine bird (Aves: Ornithothoraces) from Gansu Province,north‐western China

In recent years, the Lower Cretaceous (Aptian) Xiagou Formation has yielded approximately 100 avian partial skeletons, many with soft‐tissue traces, from sites in the Changma Basin of Gansu Province, north‐western China. The most abundant taxon amongst these is the ornithuromorph Gansus yumenensis, but enantiornithines have also been identified in the sample. Here we describe two incomplete, semi‐articulated appendicular skeletons, the first consisting of a partial left pelvic girdle and complete pelvic limb, and the second comprised of a nearly complete right pelvic limb. Both specimens bear characteristics diagnostic of Enantiornithes, and are referred to a new taxon, Qiliania graffini gen. et sp. nov. The exceptional, three‐dimensional preservation of these specimens (compared to the crushed, nearly two‐dimensional condition of most other Early Cretaceous avian fossils) reveals new information regarding enantiornithine anatomy, evolution, and diversity. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 162 , 201–219.     

“早期接触临床”教学模式在“医学微生物学”课程改革中的探索

“早期接触临床、进入医生角色”是21世纪我国高等医学教育改革的主流方向。立足现行临床医学专业五年制“医学微生物学”教学模式的不足,从理论和实践教学两方面进行改革,增加“早期接触临床”理念的理论课、讨论课和见习课,构建适合本课程的“早期接触临床”教学模式。通过期末考试卷面成绩分析及问卷调查评价教学效果。结果表明“早期接触临床”教学模式可有效整合基础理论与临床实践,激发学生的学习动力,并在一定程度上提高学生的学习成绩和综合分析能力,同时加深学生对医学和职业的理解。     

东祁连山高寒草甸不同退化阶段植被/土壤磷素特征及其与生物量的关系

磷素是高寒草地生态系统的重要支持元素,高寒草甸退化导致较为严重的生态和生产问题,同时也引起了生态系统物质循环的变化。为揭示高寒草甸退化中土壤磷素特征及其对植被特征的效应,以东祁连山轻度(LD)、中度(MD)、重度退化(SD)高寒草甸退化阶段为研究对象,以多年围封高寒草甸(FG)为对照,在春季和夏季分别对不同高寒草甸阶段样地不同土层深度土壤全磷、有效磷、微生物量磷含量及碱性磷酸酶活性等磷素特征进行了研究,并对夏季植被地上生物量和磷素含量等植被特征进行了调查。结果表明：东祁连山高寒草甸退化导致植被地上生物量和磷含量急剧下降,重度退化高寒草甸地上生物量干重仅是围封草地的35.93%,退化高寒草甸地上部磷含量仅为围封草地的60%,且不同退化阶段地上部磷含量没有明显差异。退化导致高寒草甸表层土壤的全磷、有效磷含量升高,相比FG,土壤有效磷含量春季LD、MD和SD分别升高了16.67%、36.67%和3.33%,夏季分别升高了4.35%、26.09%和4.35%,且有效磷含量具有夏季低于春季的季节差异性。退化导致土壤微生物量磷含量明显降低,而对碱性磷酸酶活性影响没有明显的规律性,但围封草地夏季碱性...     

基于NOAA-AVHRR数据的中国东部地区植被遥感分类研究

该文采用 19幅 (时间跨 8个月 ) 时间序列的NOAA_AVHRR的归一化植被指数 (NDVI) 最大值合成影像遥感数据, 经过主分量分析 (Principlecomponentanalysis, PCA) 处理后, 用非监督分类方法的ISODATA算法, 对中国东部地区的 (五省一市 ) 植被进行分类, 结果可以分出 2 8种土地覆盖类型, 除了两种类型为水体和城市或裸地外, 其余 2 6种类型均为植被类型, 根据中国植被分类系统, 这 2 6类可以归并为 6大植被类型 :1) 常绿阔叶林 ;2 ) 针叶林 ;3) 竹林 ;4 ) 灌草丛 ;5 ) 水生植被 ;6 ) 农业植被。用 1∶10 0 0 0 0 0数字化《中国植被图集》的植被类型检验遥感分类结果表明, 针叶林、灌草丛、常绿阔叶林和农业植被的分类具有较高的位置精度和面积精度, 位置精度分别为 79.2 %、91.3%、6 8.2 %和 95.9%, 面积精度分别达到 92.1%、95.9%、6 3.8%和 90.5 %。这 6大植被类型在地理空间上的分布规律与中国东部常绿阔叶林区植被的地带性分布基本一致。     

Programmed cell death during development of cowpea (Vigna unguiculata (L.) Walp.) seed coat

The seed coat develops primarily from maternal tissues and comprises multiple cell layers at maturity, providing a metabolically dynamic interface between the developing embryo and the environment during embryogenesis, dormancy and germination of seeds. Seed coat development involves dramatic cellular changes, and the aim of this research was to investigate the role of programmed cell death (PCD) events during the development of seed coats of cowpea [Vigna unguiculata (L.) Walp.]. We demonstrate that cells of the developing cowpea seed coats undergo a programme of autolytic cell death, detected as cellular morphological changes in nuclei, mitochondria, chloroplasts and vacuoles, DNA fragmentation and oligonucleosome accumulation in the cytoplasm, and loss of membrane viability. We show for the first time that classes 6 and 8 caspase‐like enzymes are active during seed coat development, and that these activities may be compartmentalized by translocation between vacuoles and cytoplasm during PCD events.     

Effects of the geomorphometric characteristics of the local terrain on floristic composition in the central Brazilian Amazon

The objective of this study was to identify the effects of local geomorphometry on the abundance, richness and floristic composition of tree species in the central Brazilian Amazon. Forty‐six 0.25‐ha plots in different phyto‐ecologic sites were sampled, and their trees were inventoried. Geomorphometric data (elevation, slope, aspect, plan and profile curvatures) were derived from Shuttle Radar Topography Mission data. A detrended correspondence analysis (DCA) was used to examine the floristic distribution patterns among plots. In addition, geomorphometric variables were submitted to multiple regression analysis to identify the variables influencing floristic composition (represented by the first DCA component), abundance and species richness. Correlation analyses between the number of individuals from each species and the first DCA component were performed to evaluate the contribution of each species. Analysis of the results could not confirm an effect of geomorphometry alone on species richness and abundance, although floristic composition was significantly influenced by profile curvature and elevation. Despite the relatively low variation in altitude at the study site, species were found to be sensitive to terrain peculiarities such as elevation and profile curvature, which can constrain particular ecologic niches and contribute to the spatial distribution patterns of species.     

Phylogenetic and phenotypic originality and abundance in a cerrado plant community

The originality of a species is how much that species contributes to the rarity of traits in a community. Here we tested the relation between abundance and both phylogenetic and phenotypic originality. We measured nine traits associated with defence against herbivory, as well as phylogenetic information and abundance for woody plant species in a woodland cerrado in southeastern Brazil. About 90% of the species accounted for about 50% of the phylogenetic and phenotypic originality: most woody species had low originality. Abundance was related to tougher leaves, lower specific leaf area and lower originality based on nutritional quality. Our results suggest that herbivory may reduce the abundance of species with low resistance to herbivory and with different nutritional quality. Nevertheless, abundance was not related to either phylogenetic or phenotypic originality, so extinction of rare species may not endanger overall community function as long as more abundant species are retained. We argue that this is a consequence of the low complementarity of a large number of woody species.     

Floral biology of Eriope blanchetii (Lamiaceae) in coastal sand dunes of NE Brazil

Abstract The floral biology of the sand dune shrub Eriope blanchetii (Benth) Harley was investigated in a wild population located within an environment protection area near Salvador, NE Brazil. Inflorescence and flower development were monitored, and the reproductive biology was assessed. Inflorescences are terminal panicles, each bearing from one to 38 small, zygomorphic flowers. The duration of an inflorescence is about 2 months, with few new flowers each day. The rewards to visitors are pollen and nectar, the latter being produced in small quantities at the corolla base, near the stylopodium. Three sequential phases of flower development were identified, based on colour changes, pollen and nectar availability, and stigmatic receptivity. Anthesis takes place throughout the day within each plant, and flowers are strongly protandrous. Flowers are short‐lived, with individual variations of 7–30 h until corolla abscission. This variation is probably associated to a post‐pollinating response, which reduces the length of the female phase and could be advantageous for the economy of nectar production and for increased efficient pollination of the remaining flowers on a plant. The results of the pollination tests (apomixis, spontaneous and manual autogamy, manual cross‐pollination, and control) reinforced the role of pollinators for the reproductive success of E. blanchetii, given that the production of fruits from spontaneous pollination is unlikely to be resulting from protandry and given the morphological floral features. Taken together, the morphological and physiological aspects of E. blanchetii floral biology favour cross‐pollination, and it is likely that most of the fruits in nature are produced by outcrossing.     

浙江天童国家森林公园常绿阔叶林主要组成种的种群结构及更新类型

 以浙江天童国家森林公园常绿阔叶林为对象,应用永久样方法和每木调查法调查了群落种类组成和结构,并对主要组成种的种群结构进行了分析。依据胸径级频率分布的形状,将各树种的种群结构归纳为5种类型,并结合生物学、生态学特征,分别讨论了其更新类型,同时对调查群落所处的演替阶段进行了诊断。结果表明：1）群落为6种共优势群落,出现木本植物69种。2）种群结构为单峰型的马尾松（Pinus massoniana）、枫香（Liquidambar formosana）和檫木（Sassafras tzumu）等为阳性高大乔木,无正常更新能力,更新类型是先锋群落优势种或是顶极性先锋种;间歇型的木荷（Schima superba）、黑山山矾（Symplocos heishanensis）和红楠（Machilus thunbergii）等为具有耐荫性的常绿阔叶树种,更新具有波动性和机会性,是演替系列或顶极群落优势种;逆-J字型的米槠（Castanopsis carlesii）、栲树（Castanopsis fargesii）和长叶石栎（Lithocarpus harlandii）等为强耐荫性的常绿阔叶树种,通过幼苗库和根萌生枝进行更新,是顶极群落的优势种;浙江新木姜子（Neolitsea aurata var. chekiangensis）、厚皮香（Ternstroemia gymnanthera）等为L字型;连蕊茶（Camellia fraternna）、老鼠矢（Symplocos stellaris）等为单柱型,此二型是群落亚乔木层和灌木层的主要组成种。3）调查群落已进入演替的顶极阶段,但仍处于其前期,将进一步向以米槠、栲树为主要优势种的方向发展。