Institutional Repository of Chengdu Institute of Biology, CAS
Not a member yet
6513 research outputs found
Sort by
Amphibian Species Contribute Similarly to Taxonomic, but not Functional and Phylogenetic Diversity: Inferences from amphibian Biodiversity on Emei Mountain
No full textUnderstanding the relationships between species, communities, and biodiversity are important challenges in conservation ecology. Current biodiversity conservation activities usually focus on species that are rare, endemic, distinctive, or at risk of extinction. However, empirical studies of whether such species contribute more to aspects of biodiversity than common species are still relatively rare. The aim of the present study was to assess the contribution of individual amphibian species to different facets of biodiversity, and to test whether species of conservation interest contribute more to taxonomic, functional, and phylogenetic diversity than do species without special conservation status. To answer these questions, 19 000 simulated random communities with a gradient of species richness were created by shuffling the regional pool of species inhabiting Emei Mountain. Differences of diversity values were then computed before and after removing individual species in these random communities. Our results indicated that although individual species contributed similarly to taxonomic diversity, their contribution to functional and phylogenetic diversity was more idiosyncratic. This was primarily driven by the diverse functional attributes of species and the differences in phylogenetic relationships among species. Additionally, species of conservation interest did not show a significantly higher contribution to any facet of biodiversity. Our results support the claims that the usefulness of metrics based only on species richness is limited. Instead, assemblages that include species with functional and phylogenetic diversity should be protected to maintain biodiversity
Dynamics and Controls of Carbon Use Efficiency across China's Grasslands
No full textChina's grasslands play a significant role in the carbon cycle. Accurately evaluating carbon use efficiency (CUE) of grassland ecosystems is of great importance. Therefore, we adopted moderate resolution imaging spectroradiometer documents to explore dynamics and controls of CUE across grasslands of China from 2001 to 2010. Results demonstrated that CUE presented an increasing trend (0 to 0.0067 year(-1)) in the most studies regions except for desert steppe (-0.0046 to 0 year(-1)). At spatial scale, the precipitation, temperature, and aridity index significantly regulated the dynamics of CUE in alpine grasslands. Furthermore, the different mechanisms are explored at the transect scale, and CUE revealed the positive correlation with aridity index (R-2 = 0.92, P<0.0001) and precipitation (R-2 = 0.88, P<0.0001), but a negative correlation with temperature (R-2 = 0.92, P<0.0001) in alpine grasslands. However, in temperate grasslands, CUE exposed the negative correlation with aridity index (R-2 = 0.40, P<0.0001) and precipitation (R-2 = 0.54, P<0.0001), but a positive correlation with temperature (R-2 = 0.56, P<0.0001). Moreover, precipitation was decreasing with the increased temperature in the alpine grasslands (R-2 = 0.85, P<0.0001) and temperature of grasslands (R-2 = 0.19, P<0.0001). In conclusion, CUE had a slight increased trend across grasslands in China, with higher precipitation, aridity index, and lower temperature promoting CUE in the alpine region - nevertheless restraining the CUE variations in grassland temperature. The better heat and water conditions in temperate grasslands than in alpine grasslands resulted in higher CUE in temperate grasslands
Characterization of Trichococcus paludicola sp nov and Trichococcus alkaliphilus sp nov., isolated from a high-elevation wetland, by phenotypic and genomic analyses
No full textTwo psychrotolerant facultative anaerobes, strains B7-2(T) and B5(T), were isolated from the Zoige Wetland on the Qinghai-Tibetan Plateau. The 16S rRNA gene sequences of strains B7-2(T) and B5(T) shared high similarity (>99?%) with those of the type strains of the genus Trichococcus, while their digital DNADNA hybridization values with each other (49?%) and with the reference type strains (4823?%) were lower than 70?%, which suggest that they represent two novel species of the genus Trichococcus. Cells of strains B7-2(T) and B5(T) were immotile cocci, grew in the temperature range of 437 degrees C (optimum 25 degrees C) and were alkaliphilic with optimum growth at pH 9.0. The major components of the cellular fatty acids were C-16:0, anteiso-C-17:0 and C-18:0 for strain B7-2(T), and C-16:0, anteiso-C-17:0, C-18:1 omega 9c and C-18:0 for strain B5(T). The genomic DNA G+C contents were 46.0 and 46.7 mol% for strains B7-2(T) and B5(T), respectively. Based on physiological and genomic characteristics, it is suggested that strains B7-2(T) and B5(T) represent two novel species within the genus Trichococcus, for which the names Trichococcus paludicola sp. nov. and Trichococcus alkaliphilus sp. nov. are proposed. The type strains are B7-2(T) (=DSM 104691T=KCTC 33886(T)) and B5(T) (=DSM 104692(T)=KCTC 33885(T)), respectively
Reintroduction of the giant panda into the wild: A good start suggests a bright future
No full textReintroduction is an important approach in the conservation of endangered species and in recent decades a number of reintroduction programs have been conducted for conservation purposes. Generally, the success rate of reintroduction is low, but long-term monitoring of most reintroduction programs remains uncommon and this may influence the evaluation of reintroduction. The giant panda is a flagship species of biodiversity conservation. The Chinese government runs a giant panda reintroduction program and here we present reintroduction monitoring data from 2009 to 2015 for three giant pandas released into a small isolated wild population in western Sichuan, China. The results indicate that all three giant pandas display similar activity patterns to wild giant pandas, however, the wild-caught female demonstrated better adaptive ability to the wild environment than the two captive-born individuals in that she established a stable home range in the quickest time and gave birth to a cub. Genetic analysis indicates that new genetic material has been introduced into the local population. Our study provides the latest update on the giant panda introduction program and indicates that it is progressing well
De novo assembly of leaf transcriptome of Lespedeza bicolor (Fabaceae: Papilionoideae) and characterization of EST-SSR markers
No full text胡枝子(Lespedeza bicolor)系豆科胡枝子属植物,性耐旱,是防风固沙及水土保持的优良植物. 报道胡枝子的转录组序列,对其进行注释,并开发一系列EST-SSR标记用于进化研究. 主要研究结果如下:(1)采用二代测序技术对胡枝子叶片进行转录组测序,得到120 913 unigenes,其平均长度为608 bp,N50的长度是978 bp.(2)分别在KEGG和KOG等数据库中对unigenes进行注释,总共注释72 613(60.05%)unigenes的功能.(3)筛选识别13 551个潜在的EST-SSR标记;根据重复单位的核苷酸数目以及重复次数的多少,从中选择173个EST-SSR标记进行引物设计.(4)对胡枝子和其他9种近缘种植物进行PCR扩增实验,最后得到56对引物可全部成功扩增出条带并表现出一定的多态性. 本研究获得了较高质量的胡枝子转录组数据库,可进一步用于比较和功能基因组研究以及胡枝子及其近缘类群的基因表达研究;开发的EST-SSR标记将提供一个强大的工具,可用于研究遗传多样性和种群结构、构建DNA指纹图谱数据库、生成遗传图谱、预测分子标记辅助育种和保存遗传信息
Relationships between relief amplitude and population distribution in southwestern China
No full text区域人口与资源环境的协调发展是可持续发展的重要方面。文中以中国西南地区30m分辨率DEM数据和2010年人口统计数据为基础,通过窗口分析法和均值变点分析法提取区域地形起伏度并分析其分布特征和规律;采用人口密度和人口集中度指标对区域人口集疏格局进行分析;进而通过分析地形起伏度与人口分布的相关性探讨二者之间的内在关系。研究结果表明: 1)西南地区地形起伏度以中小起伏为主,中部的青藏高原东南缘、横断山区和川西高原整体起伏较大,东南部云贵高原所在区域次之,西北部的青藏高原面和东北部成都平原地形起伏最低。2)县域尺度上人口密度分布与地形起伏度分布的整体格局基本一致,小起伏地区人口密度最大,大起伏、极大起伏地区人口密度较小且存在大量无人区;人口集中度则以均值区和密集区为主,整体呈现出西疏东密的集疏格局。3)地形起伏度与海拔是影响人口分布的重要因素,人口集聚主要发生在低海拔、小起伏所在的盆地丘陵区,而人口稀疏则主要分布在高海拔、大起伏所在的高山高原区
Isolation of an insecticidal metabolite from Bionectria ochroleuca YLZ42 based on the brine shrimp lethality test
No full text淡色生赤壳菌具有优良的生防潜力.本实验室前期从广西玉林土壤中分离到一株对小菜蛾等多种农业害虫具有毒杀作用的淡色生赤壳菌YLZ42.采用杀虫活性追踪的方法,用改进后的卤虫致死试验(Brine shrimp lethality test,BSLT)进行活性评价,通过硅胶柱层析、萃取、薄层制备、液相制备的手段进行分离纯化,并探索活性化合物的生物活性和稳定性.分离到杀虫活性化合物纯品,高分辨率质谱显示该活性化合物相对分子质量为788,其对卤虫24 h的LC50为86.89 mg/L.该化合物在温度低于30 ℃,pH 6-8以及光照和紫外光照条件下活性稳定.该杀虫活性化合物的氢谱与已报道过的分子量为788的化合物均不相同,有望开发为新的微生物源杀虫剂
Research progress on pollen-inferred Holocene climate histories in southwestern China
No full text研究全新世以来的气候变化特征是当今世界范围内古气候研究的重点和热点.位于亚洲东南部的中国西南地区地貌类型复杂,其气候变化不仅受全球性气候因素驱动,也显著受其他区域性因素的影响,更加具有复杂性.在对中国西南地区全新世以来孢粉重建古气候相关研究整合分析的基础上,归纳总结该区百年时间尺度上全新世植被演替和气候变化的主要特征.主要通过综述西南地区典型地理单元全新世以来的气候演替特征,进而围绕区域性和全球性的气候突变事件进行比较研究,结果表明西南地区全新世以来总体呈现湿润的气候特征,即早期(11.5-8 ka BP)气候从干冷向暖湿转变,中期(8-3.5 ka BP)温暖湿润,晚期(3.5 ka BP至今)气候向减湿方向发展;该区气候对于8.2 ka BP冷事件的响应不如5.5 ka BP冷事件明显,表明该区具有相对独特的区域性气候特征.最后鉴于西南地区全新世古气候研究相对滞后的现状,指出未来不仅需要加快区域孢粉数据集成,也要积极引入新方法、新指标进行对比验证,从而实现对区域气候变化的深入理解
Nutritional components,textural properties,and in vitro starch hydrolysis of steamed hulless barley bread
No full text青稞是我国藏区的主要农作物,富含beta-葡聚糖、黄酮、生育酚等多种生理活性成分.通过比较分析青稞全麦粉和小麦粉的粉质和糊化特性差异,研制青稞全麦粉占面粉含量60%的高青稞含量的青稞全麦馒头粉,并对青稞全麦馒头的营养、感官、质构以及体外淀粉水解等方面的特性进行评价.结果显示:(1)青稞全麦粉吸水率、弱化度显著高于小麦粉,面团形成时间、稳定时间以及粉质质量指数显著低于小麦粉,通过添加谷朊粉,青稞全麦馒头粉的粉质特性得到了改善,其面团形成时间和稳定时间延长,弱化度降低,粉质质量指数增加;青稞全麦粉比小麦粉更易糊化,峰值粘度、崩解值和回生值增加,混粉后青稞全麦馒头粉的低谷粘度与小麦粉差异显著,其他参数无显著差异;(2)青稞全麦馒头的蛋白质和beta-葡聚糖含量都显著高于小麦馒头,其中beta-葡聚糖含量为2.33%-2.78%,是小麦馒头的10倍;(3)青稞全麦馒头感官品质显著低于小麦馒头,但仍具有较好的整体接受度;(4)与小麦馒头比较,青稞全麦馒头的硬度、胶着性、咀嚼度等指标显著增加,而粘附性、回复性等指标则显著降低;(5)青稞全麦馒头的抗性淀粉(RS)含量显著高于小麦馒头,而极易消化淀粉(VRDS)、易消化淀粉(RDS)、血糖生成指数(GI)均显著低于小麦馒头.本研究表明,青稞全麦馒头不仅具有独特的口感和香味,而且比小麦馒头具有更高的营养价值,尤其是低GI值,可缓解餐后血糖指数的升高,更利于人们对血糖的控制,因而青稞可以作为一种优质的主要原料用于馒头加工
Spatial distribution and risk assessment of soil heavy metal contamination along roadsides of the northwestern Sichuan Plateau, China
No full text道路交通活动可导致道路两侧土壤重金属污染.为了解川西北高原路侧土壤重金属污染状况,以四川省阿坝州红原县为例,研究不同车流量区域路侧重金属镉(Cd)、铜(Cu)、镍(Ni)、铅(Pb)、锌(Zn)的分布特征与规律,并采用单项污染指数法、尼梅罗综合污染指数法和潜在生态危害指数法评价公路交通导致的重金属污染情况.结果表明:车流量增加对区域路侧土壤重金属含量产生了一定程度的影响,路侧土壤Cd和Zn含量均高于高寒草甸土壤的背景值含量,并随车流量增加呈上升趋势.基于单项污染指数法的结果显示3种车流量等级区域路侧都受到Cd重度污染,部分区域受Ni、Pb、Zn轻度污染.基于尼梅罗综合污染指数法的结果显示车流量大的区域路侧土壤存在重金属中度污染,车流量中等和车流量低的区域路侧土壤存在重金属轻度污染.总体上,由于本地区道路建设和使用年限相对较短,与其他重金属污染严重的城市或地区比较,路侧重金属染污生态风险中等,但部分重金属元属(如Cd和Zn)的生态风险较大,随着道路使用年限的增加势必对当地生态平衡产生影响,需引起重视