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解读龙母故事的断尾母题 被引量:5
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作者 姚立江 邵非 《宁夏大学学报(人文社会科学版)》 2001年第3期66-68,共3页
在中国古代的龙母故事中 ,普遍存在着一个断尾化龙的情节 ,断尾———化龙形成一种固定的联结关系和必然的因果关系 ,表现出明显的母题性质。从深层意蕴来看 ,动物化龙象征着对生命凡俗性、有限性的升华与超越 ,而断尾母题则是生命“过... 在中国古代的龙母故事中 ,普遍存在着一个断尾化龙的情节 ,断尾———化龙形成一种固定的联结关系和必然的因果关系 ,表现出明显的母题性质。从深层意蕴来看 ,动物化龙象征着对生命凡俗性、有限性的升华与超越 ,而断尾母题则是生命“过渡仪式”的符号表征 ,隐喻着人只有通过某种仪式才能完成角色转变、人格转变、精神转变 ,使生存方式与生命形态提升到一个全新的阶段。 展开更多
关键词 神话传说 龙母事故 断尾母题 象征意蕴 生成依据 中国 生物变态现象 置换现象
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Analysis on the Essential Characters and Biological Yield Change of Purple-fleshed Sweetpotato Xuzishu 3
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作者 唐维 李强 +3 位作者 张允刚 王欣 后猛 马代夫 《Agricultural Science & Technology》 CAS 2014年第10期1660-1666,共7页
Objective] This study was performed to investigate the trait changes and their correlations as wel as the dynamic changes of biological yield of Xuzishu 3, which wil help to enhance the yield and anthocyanin content o... Objective] This study was performed to investigate the trait changes and their correlations as wel as the dynamic changes of biological yield of Xuzishu 3, which wil help to enhance the yield and anthocyanin content of sweetpotato by cul-tivation. [Method] We systematical y measured the agronomic traits, qualitative char-acters and biological yield of Xuzishu 3 during six growing periods to investigate the dynamic changes of its essential characters and yield accumulation. [Result] The characters of Xuzishu 3 appeared most prosperous after the 90th d except for an-thocyanin content. Extremely significant positive correlations were found between ev-ery two of the dry matter rates of above-ground parts (including leaf petioles, leaves and stems), reducing sugar content and potato weight per plant. Assimilated product distributed more in stems and leaves than in storage roots before the 90th d in growing period. Photosynthetic capacity and net assimilation rate gradual y de-creased after the 90th d, but the assimilated product distributing to storage roots in-creased quickly and maximized in the 135th d. [Conclusion] Xuzishu 3 is a late ma-turing variety requiring more fertilizer, and the accumulation of anthocyanin fluctuates during the growth period of Xuzishu 3. So yield of Xuzishu 3 can be increased by applying more fertilizer and extending the growth period reasonably, meanwhile the anthocyanin content can be increased by means of control ing temperature, light, water and phytohormone within 60 d after planting. 展开更多
关键词 Purple-fleshed sweetpotato CHARACTER CORRELATION Biological yield Dynamic change
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EXAMINATION OF SILICATE LIMITATION OF PRIMARY PRODUCTION IN JIAOZHOU BAY, CHINA I. SILICATE BEING A LIMITING FACTOR OF PHYTOPLANKTON PRIMARY PRODUCTION 被引量:31
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作者 杨东方 张经 +2 位作者 吕吉斌 高振会 陈豫 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2002年第3期208-225,共18页
Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou Bay, were analyzed to determine the spatiotemporal variations i... Jiaozhou Bay data collected from May 1991 to February 1994, in 12 seasonal investigations, and provided the authors by the Ecological Station of Jiaozhou Bay, were analyzed to determine the spatiotemporal variations in temperature, light, nutrients (NO - 3 N, NO - 2 N, NH + 4 N, SiO 2- 3 Si, PO 3- 4 P), phytoplankton, and primary production in Jiaozhou Bay. The results indicated that only silicate correlated well in time and space with, and had important effects on, the characteristics, dynamic cycles and trends of, primary production in Jiaozhou Bay. The authors developed a corresponding dynamic model of primary production and silicate and water temperature. Eq.(1) of the model shows that the primary production variation is controlled by the nutrient Si and affected by water temperature; that the main factor controlling the primary production is Si; that water temperature affects the composition of the structure of phytoplankton assemblage; that the different populations of the phytoplankton assemblage occupy different ecological niches for C , the apparent ratio of conversion of silicate in seawater into phytoplankton biomas and D , the coefficient of water temperature’s effect on phytoplankton biomass. The authors researched the silicon source of Jiaozhou Bay, the biogeochemical sediment process of the silicon, the phytoplankton predominant species and the phytoplankton structure. The authors considered silicate a limiting factor of primary production in Jiaozhou Bay, whose decreasing concentration of silicate from terrestrial source is supposedly due to dilution by current and uptake by phytoplankton; quantified the silicate assimilated by phytoplankton, the intrinsic ratio of conversion of silicon into phytoplankton biomass, the proportion of silicate uptaken by phytoplankton and diluted by current; and found that the primary production of the phytoplankton is determined by the quantity of the silicate assimilated by them. The phenomenon of apparently high plant nutrient concentrations but low phytoplankton biomass in some waters is reasonably explained in this paper. 展开更多
关键词 PHYTOPLANKTON silicon limiting factor Jiaozhou Bay
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Effects of experimental warming on soil microbial communities in two contrasting subalpine forest ecosystems,eastern Tibetan Plateau,China 被引量:8
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作者 SUN Di-di LI Yue-jiao +4 位作者 ZHAO Wen-qiang ZHANG Zi-liang LI Dan-dan ZHAO Chun-zhang LIU Qing 《Journal of Mountain Science》 SCIE CSCD 2016年第8期1442-1452,共11页
Soil microbial communities are primarily regulated by environmental temperature. Our study investigated the effects of global warming on soil microbial community composition as measured via phospholipid fatty acid (P... Soil microbial communities are primarily regulated by environmental temperature. Our study investigated the effects of global warming on soil microbial community composition as measured via phospholipid fatty acid (PLFA) analysis and soil chemical characteristics in relation to soil depth in a dragon spruce plantation and a spruce-fir-dominated natural forestin the Eastern Tibetan Plateau. Opentop chambers were utilized to increase the soil and air temperature. Soil samples were collected from the o-10 cm, 10-20cm, and 20-30 cm layers after a 4-year warming. Our results showed that the soil microbial community and the contents of TC (Total carbon), TN (Total nitrogen). NO3-. and NH4+ responded differently to warming in the two contrasting forests, especially at the 0-10 cm soil depth. Warming increased soil microbial biomass at the 0-20 cm depth of soil in natural forest but reduced it at the o-lo cm depth ofsoil in the plantation. In contrast, the TC and TN contents were reduced in most soil layers of a natural forest but increased in all of the soil layers of the plantation under warming conditions. This result suggested that the effects of warming on soil microbial community and soil C and N pools would differ according to soil depth and forest types; thus, the two contrasting forests would under go differing changes following the future climate warming in this region. 展开更多
关键词 Microbial biomass Microbialcommunity Phospholipid fatty acid (PLFA) EASTERN
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Microecosystem of ostiomeatal complex and the changes via functional endoscopic sinus surgery 被引量:1
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作者 钟诚 张学渊 《Journal of Medical Colleges of PLA(China)》 CAS 2004年第5期311-315,共5页
Objective: To study the composition of microecosystem in ostiomeatal complex (OMC) of adults and the changes via functional endoscopic sinus surgery. Methods: 220 adults with chronic sinusitis(20 as control) were clas... Objective: To study the composition of microecosystem in ostiomeatal complex (OMC) of adults and the changes via functional endoscopic sinus surgery. Methods: 220 adults with chronic sinusitis(20 as control) were classified into pre- and post-operative groups, and categorised according to its type of sinusitis. Swab specimens were taken from three different sites of ostiomeatal complex in each individual, and cultivations and identifications of aerobes, anaerobes and fungi were performed simultaneously. The microecosystem was analysed. Results: Cultured aerobes belonged to 30 species from 13 genera, anaerobes species, and fungi 3 major species, most of which have none or less virulence. The difference of mi-croecological status between type Ⅰ and Ⅱ was not significant (P > 0.05). Aerobic culture rates between preoperative group and control group had significance(P < 0.01);culture rate descended in postoperative group while the difference was not significant compared to preoperative group (P > 0. 05); difference of rate of same aerobic culture from three sites (RSAC) , which reflects the microecological integrity of OMC, between preoperative and control group was significant (P < 0.01), while was not between postoperative group and control one(P > 0. 05). Taking fungi into account, differences among all groups had no significance(P>0.05); anaerobes were rare in all groups. Conclusion: Being a microecosystem under normal condition, ostiomeatal complex is relatively clean and exists as a whole space. Chronic inflammations separate different parts of which from each other with multimicrobial existence.FESS reverses separation of the microecosystem and rebuild it as a whole again, thus promote the recovery. 展开更多
关键词 ostiomeatal complex microecosystem ENDOSCOPE
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Ecological Responses to Holocene Millennial-Scale Climate Change at High Altitudes of East and Central Asia: A Case Study of Picea/Abies Pollen Changes in Lacustrine Sediments 被引量:2
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作者 LI Yu ZHANG Cheng-qi ZHOU Xue-hua 《Journal of Mountain Science》 SCIE CSCD 2014年第3期674-687,共14页
Ecosystem response to climate change in high-altitude regions is a focus on global change research. Picea/Abies forests are widely distributed at high altitudes of East and Central Asia, and their distribution changes... Ecosystem response to climate change in high-altitude regions is a focus on global change research. Picea/Abies forests are widely distributed at high altitudes of East and Central Asia, and their distribution changes are sensitive to climate change. Humidity is an important climatic factor that affects high-altitude ecosystems; however, the relationship between distribution changes of Picea/Abies forests and millennial-scale variability of humidity is still not dear. Palynological records can provide insights into millennial-scale paleovegetation changes, which have been successfully used to reconstruct past climate change in East and Central Asia. In this study, we synthesized 24 Picea/Abies pollen and humidity/moisture changes based upon Holocene lake records in East and Central Asia in order to explore the response of high-latitude ecosystem to millennial-scale climate change. The changing pattern of Holocene lacustrine Picea/Abies pollen in arid Central Asia differs from that of monsoonal East Asia, which can be due to different millennial-scale climate change patterns between monsoonal and arid Central Asia. Then, the relationship between changes in Picea/Abies pollen and humidity/moisture conditions was examined based on a comparison of pollen and humidity/moisture records. The results indicate that millennial-scale Picea/Abies distribution changes aremainly controlled by moisture variability at high altitudes, while the temperature effect plays a minor role in Picea/Abies distribution changes. Moreover, this research proves that lacustrine Picea/Abies pollen can be used as an indicator of millennial-scale humidity/moisture evolution at high altitudes in East and Central Asia. 展开更多
关键词 Lake sediments Palynological records High-altitude regions Picea/Abies Asian summermonsoon MILLENNIAL-SCALE Climate change
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Low Frequencies of CCR5-Δ32 and CCR5-m303,but High Frequencies of CCR2-641 and SDF1-3'A Alleles in Indigenous Ethnic Groups in China's Mainland 被引量:5
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作者 王福生 金磊 +11 位作者 洪卫国 刘明旭 周越塑 张冰 施明 王吉明 雷周云 王哲 冯铁建 侯静 李光汉 曹韵贞 《Chinese Journal of Sexually Transmitted Infections》 2002年第1期7-12,共6页
Objective: The aim in this study was to identify the allelicfrequencies of the chemokine (SDF1-3'A) and chemokinereceptor (CCR5△32, CCR5m303 and CCR2-64I) genesresistant to HIV-1 infection and/or disease progress... Objective: The aim in this study was to identify the allelicfrequencies of the chemokine (SDF1-3'A) and chemokinereceptor (CCR5△32, CCR5m303 and CCR2-64I) genesresistant to HIV-1 infection and/or disease progression inindigenous Chinese populations. Methods: By using QIAamp DNA Blood Mini Kit, thegenomic DNA samples were purified from whole peripheralblood of healthy individuals (n=2067) from Han, Uygur,Mongolian and Tibetan ethnic groups, as well as Han patientsincluding HIV-1 carriers (n=330), patients with other sexuallytransmitted diseases (STDs, n=259) and intravenous drugusers (IVDUs, n=125). The allelic polymorphisms wereidentified by means of PCR or PCR-RFLP analyses. Thesequences of randomly selected amplified PCR products werefurther confirmed by direct DNA sequencing. Results: The mutant frequencies were identified to be0%~3.48% for CCR5△32, 0% for CCR5m303,19.15%~28.79% for CCR2-64 and 19.10%~28.73% for SDF1-3'A alleles, respectively, in Chinese healthy individuals fromfour ethnic groups. Our findings indicated the allelicfrequencies vary among the different ethnic groups.Furthermore, the HIV-1 carriers, STD cases and IVDUs (all ofHan ethnicity) were found to have the allelic frequencies of0%~0.19% (CCR5△32), 0% (CCR5m303), 19.31%~20.45%(CCR2-64) and 25.61%~26.83% (SDF1-3'A) with minorvariations in their frequencies between the patients andhealthy Han groups. There was no CCR5-m303 mutationfound in any subject in this study. Conclusion: The examined subjects of four Chinese ethnicorigins showed lower frequencies of CCR5△32 andCCR5m303 alleles, but higher frequencies of mutant CCR2-64I and SDF1-3'A alleles compared to those identified innorthern-European and American Caucasians. Thesignificance of the different frequencies and polymorphisms ofthe above alleles in Chinese populations needs to be furtherexamined in HIV-1/AIDS diseases. 展开更多
关键词 HIV-1 coreceptors POLYMORPHISM Allelic frequency mutation
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Chemical Variation in Essential Oils of Salvia Officmalis L, Ecotypes Cultivated in Albania
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作者 Elvira Bazina 《Journal of Life Sciences》 2015年第3期95-102,共8页
Salvia officinalis L. was cultivated in different geographic locations of Albania. Sage plants originated from imported seeds and wild Albanian plants. Around 30 chemical compounds were identified in the essential oil... Salvia officinalis L. was cultivated in different geographic locations of Albania. Sage plants originated from imported seeds and wild Albanian plants. Around 30 chemical compounds were identified in the essential oils of all cultivated sage plants; the latter were found to be very rich in camphen, fl-thujone, a-pinene, eucaliptol, rich to moderate in β-pinene and camphor, and less rich in a-thujone and limonene. Sharp differences in chemical composition patterns and content of individual chemical compounds were noticed between and within cultivation sites. Cultivated sage was poorer in α-thujone versus wild plants. Cultivated sage, of Albanian wild plants origin, was the richest in α-thujone (18.45%) versus imported seeds sage. β-thujone over-dominated α-thujone in all cultivated sage plants. Volatile characters of cultivated sage were indicative of the species but not of the geographic origin of plant material. Variation in essential oils composition and chemical compounds' content (biosynthetic pathways) in cultivated sage is related more to the genetic background than the environmental factors. If cultivating sage in Albania, then wild local ecotypes would be best to use as α-thujone is maintained at satisfactory levels, local natural base is preserved, unnecessary hybridization with imported seeds sage is prevented, and are more resistant and cost effective. 展开更多
关键词 SAGE Headspace-GC/MC chemical composition variation cultivation.
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Oribatid Use as Bioindicateur of Environment: Case of Galumna sp. and Scheloribates sp. (Acari: Oribatida)
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作者 Ghezali Djelloul Harkat Hafsa 《Journal of Life Sciences》 2012年第5期518-527,共10页
Environmental characteristics are often the factors that determine the distribution of species in nature. However, species response vis-A-vis these factors differs. For a better understanding of the phenomenon, we hav... Environmental characteristics are often the factors that determine the distribution of species in nature. However, species response vis-A-vis these factors differs. For a better understanding of the phenomenon, we have conducted this study which consists of following the spatio-temporal evolution of two species of Oribatida (Scheloribates sp. and Galumna sp.). The sites which have been the subject of this study, are situated in different bioclimatic zones presenting a very different climatic, edaphic, nutritional, and altitudinal characteristics. The variability of ecological factors showed that the behavior of two species differs. Indeed, Scheloribates sp. is present in all sites except in Biskra whereas Galumna sp. is present only in sites belonging to humid and sub humid bioclimatic zones. Moreover, Scheloribates sp. appears more tolerant of environmental changes while Galumna sp. is more stringent and its presence is marked only in the sites where ecological conditions are better. Thus, it can be noted that the spatial and temporal distribution of oribatid is not only conditioned solely by environmental factors but also by intrinsic factors specific to each species. The specific behavior of Galumna sp. and the tolerance of Scheloribates sp. are interesting and can be the subject of bioindicator species that can inform us about the changes that effect whether natural or anthropogenic environment. 展开更多
关键词 ORIBATIDA ecological factors area bioclimatic spatiotemporal.
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动物玩家之“蛙”
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《小朋友》 2009年第A12期25-25,共1页
关键词 生物变态 脊索动物门 两栖纲 腿长 蛙科 趾间
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科学活动:小蝌蚪变青蛙
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作者 崔花琴 《儿童与健康》 2016年第9期55-56,共2页
适龄目标:大班 设计意图:我们大班的小朋友通过英语童话剧、故事“小蝌蚪找妈妈”,知道小蝌蚪最后找到的青蛙才是自己的妈妈。但对“小蝌蚪变青蛙”这一生物变态生长现象充满着好奇和不解。我在大班孩子已有经验的基础上,把“小蝌蚪... 适龄目标:大班 设计意图:我们大班的小朋友通过英语童话剧、故事“小蝌蚪找妈妈”,知道小蝌蚪最后找到的青蛙才是自己的妈妈。但对“小蝌蚪变青蛙”这一生物变态生长现象充满着好奇和不解。我在大班孩子已有经验的基础上,把“小蝌蚪变青蛙”的变态生长的生物科学用快乐的游戏和多媒体的现代化教学手段表现出来,帮助幼儿系统了解小蝌蚪变成青蛙的过程,并知道青蛙的生活习性与人们的关系,激发他们热爱小动物、保护益虫的情感。 展开更多
关键词 生物变态 现代化教学手段 生物科学 生长现象 童话剧 体态语 自主学习 教学效果 积极主动性 语言动作
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Dynamics of CO_2 Emission and Biochemical Properties of a Sandy Calcareous Soil Amended with Conocarpus Waste and Biochar 被引量:12
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作者 Mohamed EL-MAHROUKY Ahmed Hamdy EL-NAGGAR +1 位作者 Adel Rabie USMAN Mohammad Al-WABEL 《Pedosphere》 SCIE CAS CSCD 2015年第1期46-56,共11页
Biochar is a carbon-rich product obtained by biomass pyrolysis and considered a mean of carbon sequestration. In this research, a sandy calcareous soil from the Farm of the College of Food & Agriculture Sciences, ... Biochar is a carbon-rich product obtained by biomass pyrolysis and considered a mean of carbon sequestration. In this research, a sandy calcareous soil from the Farm of the College of Food & Agriculture Sciences, King Saud University, Saudi Arabia, was amended with either woody waste of Conocarpus erectus L.(CW) or the biochar(BC) produced from CW at rates of 0(control), 10, 30 and 50 g kg-1. The effects of the amendments on soil p H, dissolved organic carbon(DOC), microbial biomass carbon(MBC), CO2 emission and metabolic quotient(q CO2) of the sandy calcareous soil were studied in a 60-d incubation experiment. The results showed that the addition of CW led to a significant decrease in soil p H compared to the control and the addition of BC. The CO2-C emission rate was higher in the first few days of incubation than when the incubation time progressed. The cumulative CO2-C emission from the soil amended with CW, especially at higher rates, was higher(approximately 3- to 6-fold) than that from the control and the soil amended with BC. The BC-amended soil showed significant increases in CO2-C emission rate during the first days of incubation as compared to the non-amended soil, but the increase in cumulative CO2-C emission was not significant after 60 d of incubation. On the other hand, CW applications resulted in considerably higher cumulative CO2-C emission, MBC and DOC than the control and BC applications. With the exception of 0 day(after 1 h of incubation), both CW and BC applications led to lower values of q CO2 as compared to the control. The power function kinetic model satisfactorily described the cumulative CO2-C emission. Generally, the lowest values of CO2 emission were observed in the soil with BC, suggesting that the contribution of BC to CO2 emission was very small as compared to that of CW. 展开更多
关键词 dissolved organic carbon metabolic quotient microbial biomass carbon power function kinetic model soil pH
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Temporal Variations in Growth and Aboveground Biomass of Phragmites australis and EVI Analysis in Jiaozhou Bay Coastal Salt Marshes, China 被引量:1
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作者 Xl Min KONG Fanlong LI Yue 《Journal of Resources and Ecology》 CSCD 2017年第6期641-647,共7页
To better ascertain leaf, stem and flower traits, and analyze aboveground allocation during the vegetation period, three sampling vegetation transects were settled and reed samples were collected at intervals to deter... To better ascertain leaf, stem and flower traits, and analyze aboveground allocation during the vegetation period, three sampling vegetation transects were settled and reed samples were collected at intervals to determine morphological parameters and dry and wet weights in Jiaozhou Bay wetland. Remote sensing data were also combined to evaluate regional biomass through EVI regression models. Results show that growth dynamics of leaves and stems changed during the vegetation period. Stem length increased rapidly and peaked in September(194.40 ± 23.89 cm), whereas leaf width peaked in July. There was a significantly negative correlation between stem length and stem diameter with a value of-0.785. Stem biomass was higher than that of leaves, and the maximum value of aboveground biomass was 27.17 ± 3.56 g. F/C exhibited a tendency to increase and values ranged from 0.37–0.76. The aboveground biomass of sample plots reached a peak of 2356 ± 457 g/m^2 in September. EVI was 0.05–0.5; EVI and biomass had a better fitting effect using the power-exponent model compared with other models and its function was y = 4219.30 x^0.88(R^2 = 0.7810). R^2 of the other three models ranked as linear function〉 polynomial function 〉exponent function, with the values being 0.7769, 0.7623 and 0.6963, respectively. EVI can be used to estimate vegetation biomass, and effectively solved the problems of the destructive effect to sample plots resulting from traditional harvest methods. 展开更多
关键词 aboveground biomass temporal variations enhanced vegetation index (EVI) analysis
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Differences in functional traits among distinct populations of the plant invader Bunias orientalis 被引量:1
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作者 Blaise Binama Caroline Müller 《Journal of Plant Ecology》 SCIE CSCD 2022年第3期524-537,共14页
Plants that expand their range and become invasive in other areas may shift several functional traits in response to specific environments.However,local conditions at the place of origin may have shaped the functional... Plants that expand their range and become invasive in other areas may shift several functional traits in response to specific environments.However,local conditions at the place of origin may have shaped the functional traits,which may to some extent remain visible in plants growing in new habitats.The present study aimed to explore the trait variation in different plant populations of native,invasive and naturalized status of Bunias orientalis grown in common conditions in relation to the climatic conditions at their place of origin.Seeds of B.orientalis were collected from 12 populations(4 per status)in 8 countries and grown under standardized conditions in a common field garden.The variation in several functional traits related to phenology,growth and reproduction was compared among status and among populations.Phenology did not differ according to status.However,several plants of the native populations,originating from areas with low annual temperatures,did not start flowering.Plants of the invasive populations produced more leaves than natives,potentially indicating their vigor in building up vegetative biomass.Number and mass of silicles and other growth traits did not differ among status groups but varied among populations.Some of the variation in functional traits may be explained by long-term adaptations to local conditions at the areas of origin and genetic diversity,while other environmental factors differing in the novel environment may contribute to a high trait variation. 展开更多
关键词 Bunias orientalis invasive species PHENOLOGY ecological status trait variation
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Soil Microbiological Activity and Carbon Dynamics in the Current Climate Change Scenarios:A Review 被引量:14
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作者 Javid A.SOFI Aabid H.LONE +5 位作者 Mumtaz A.GANIE Naseer A.DAR Sajad A.BHAT Malik MUKHTAR Mohd Ashraf DAR Shazia RAMZAN 《Pedosphere》 SCIE CAS CSCD 2016年第5期577-591,共15页
Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues.Because of their prominent role in the global carbon balance and their possible rol... Microbial activities are affected by a myriad of factors with end points involved in nutrient cycling and carbon sequestration issues.Because of their prominent role in the global carbon balance and their possible role in carbon sequestration, soil microbes are very important organisms in relation to global climate changes. This review focuses mainly on the responses of soil microbes to climate changes and subsequent effects on soil carbon dynamics. An overview table regarding extracellular enzyme activities(EAA) with all relevant literature data summarizes the effects of different ecosystems under various experimental treatments on EAA. Increasing temperature, altered soil moisture regimes, and elevated carbon dioxide significantly affect directly or indirectly soil microbial activities.High temperature regimes can increase the microbial activities which can provide positive feedback to climate change, whereas lower moisture condition in pedosystem can negate the increase, although the interactive effects still remain unanswered. Shifts in soil microbial community in response to climate change have been determined by gene probing, phospholipid fatty acid analysis(PLFA),terminal restriction length polymorphism(TRFLP), and denaturing gradient gel electrophoresis(DGGE), but in a recent investigations,omic technological interventions have enabled determination of the shift in soil microbe community at a taxa level, which can provide very important inputs for modeling C sequestration process. The intricacy and diversity of the soil microbial population and how it responds to climate change are big challenges, but new molecular and stable isotope probing tools are being developed for linking fluctuations in microbial diversity to ecosystem function. 展开更多
关键词 carbon cycling carbon dioxide carbon exchange carbon sequestration microbe community soil enzymes soil moisture soil temperature
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Fusulinid species determination based on population variation:An example from Eopolydiexodina 被引量:1
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作者 HUANG Hao 《Science China Earth Sciences》 SCIE EI CAS 2011年第3期380-387,共8页
To make fusulinid morphospecies more accordant with biological species, it is necessary and reasonable to constrain the conventional determination of fusulinid species with population-level morphological variation. As... To make fusulinid morphospecies more accordant with biological species, it is necessary and reasonable to constrain the conventional determination of fusulinid species with population-level morphological variation. As an example, morphospecies identification on population level was conducted on Eopolydiexodina specimens from a single bed of the Middle Permian Shazipo Formation of Xiaoxinzhai Section in western Yunnan, China. These specimens were identified with the consideration of fossil population by morphometric analysis of their characteristic morphological variates (diameter of proloculus, size and ratio of inner and outer volutions). The results reveal that the studied variates have wide but overall continuous variation and generally follow the normal distribution. The studied individuals, therefore, have consistent morphological variation with a single population and should belong to one fusulinid morphospecies. This study supports the assumption that fusulinid individuals of one genus from the same bed in one locality should constitute a single fossil population. 展开更多
关键词 POPULATION MORPHOSPECIES biological species Eopolydiexodina fusulinid
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Inducible competitors and adaptive diversification
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作者 Beren W. ROBINSON David W. PFENNIG 《Current Zoology》 SCIE CAS CSCD 2013年第4期537-552,共16页
Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversi- fication holds that the evolution of phenotypic differences between populations and species--and... Identifying the causes of diversification is central to evolutionary biology. The ecological theory of adaptive diversi- fication holds that the evolution of phenotypic differences between populations and species--and the formation of new spe- cies-stems from divergent natural selection, often arising from competitive interactions. Although increasing evidence suggests that phenotypic plasticity can facilitate this process, it is not generally appreciated that competitively mediated selection often also provides ideal conditions for phenotypic plasticity to evolve in the first place. Here, we discuss how competition plays at least two key roles in adaptive diversification depending on its pattern. First, heterogenous competition initially generates heterogeneity in resource use that favors adaptive plasticity in the form of "inducible competitors". Second, once such competitively induced plas- ticity evolves, its capacity to rapidly generate phenotypic variation and expose phenotypes to alternate selective regimes allows populations to respond readily to selection favoring diversification, as may occur when competition generates steady diversifying selection that permanently drives the evolutionary divergence of populations that use different resources. Thus, competition plays two important roles in adaptive diversification---one well-known and the other only now emerging--mediated through its effect on the evolution ofphenotypic plasticity 展开更多
关键词 Phenotypic plasticity COMPETITION Adaptive radiation Character displacement Genetic assimilation Resourcepolymorphism
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Dynamics of ^(14)C-labelled Glucose and NH_4^+ in a Regularly Flooded Extremely Alkaline Saline Soil
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作者 Luc DENDOOVEN Eustacio RAMIREZ-FUENTES +4 位作者 Rocio ALCANTARA-HERNDEZ Cesar VALENZUELA-ENCINAS Katia Berenice SANCHEZ-LOPEZ Marco LUNA-GUIDO Victor Manuel RUIZ-VALDIVIEZO 《Pedosphere》 SCIE CAS CSCD 2015年第2期230-239,共10页
Flooding an extremely alkaline(pH 10.6) saline soil of the former Lake Texcoco to reduce salinity will affect the soil carbon(C)and nitrogen(N) dynamics.A laboratory incubation experiment was done to investigate how d... Flooding an extremely alkaline(pH 10.6) saline soil of the former Lake Texcoco to reduce salinity will affect the soil carbon(C)and nitrogen(N) dynamics.A laboratory incubation experiment was done to investigate how decreasing soil salt content affected dynamics of C and N in an extremely alkaline saline soil.Sieved soil with electrical conductivity(EC) of 59.2 dS m^(-1) was packed in columns,and then flooded with tap water,drained freely and conditioned aerobically at 50%water holding capacity for a month.This process of flooding-drainage-conditioning was repeated eight times.The original soil and the soil that had undergone one,two,four and eight flooding-drainage-conditioning cycles were amended with 1000 mg glucose-^(14)C kg^(-1) soil and 200 mg NH_4^+-N kg^(-1)soil,and then incubated for 28 d.The CO_2 emissions,soil microbial biomass,and soil ammonium(NE_4^+),nitrite(NO_2^-) and nitrate(NO_3^-) were monitored in the aerobic incubation of 28 d.The soil EC decreased from 59.2 to 1.0 dS m^(_1) after eight floodings,and soil pH decreased from 10.6 to 9.6.Of the added ^(14)C-labelled glucose,only 8%was mineralized in the original soil,while 24%in the soil flooded eight times during the 28-d incubation.The priming effect was on average 278 mg C kg^(-1) soil after the 28-d incubation.Soil microbial biomass C(mean 66 mg C kg^(-1) soil) did not change with flooding times in the unamended soil,and increased 1.4 times in the glucose-NH_4^+-amended soil.Ammonium immobilization and NO_2^- concentration in the aerobically incubated soil decreased with increasing flooding times,while NO_3^- concentration increased.It was found that flooding the Texcoco soil decreased the EC sharply,increased mineralization of glucose,stimulated nitrification,and reduced immobilization of inorganic N,but did not affect soil microbial biomass C. 展开更多
关键词 C mineralization CO2 emission microbial biomass C mineral N NITRIFICATION
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Evolution of discocephalid ciliates:Molecular,morphological and ontogenetic data support a sister group of discocephalids and pseudoamphisiellids (Protozoa,Ciliophora) with establishment of a new suborder Pseudoamphisiellina subord.n. 被引量:2
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作者 MIAO Miao SHAO Chen +1 位作者 CHEN XuMiao SONG WeiBo 《Science China(Life Sciences)》 SCIE CAS 2011年第7期634-641,共8页
Discocephalids and pseudoamphisiellids are possibly two of the most confused groups among hypotrichous/euplotid ciliates regarding their systematic position and phylogenetic relationships.The former were often regarde... Discocephalids and pseudoamphisiellids are possibly two of the most confused groups among hypotrichous/euplotid ciliates regarding their systematic position and phylogenetic relationships.The former were often regarded as related to euplotids while the latter,in the absence of molecular data,were mostly assigned to the urostylid-like hypotrichs.In the present work,the small subunit rRNA genes of several rarely observed discocephalid and pseudoamphisiellid genera were analyzed to obtain insights into the phylogenetic relationships of these highly ambiguous Spirotrichea.Four different tree reconstruction algorithms yielded nearly identical topologies,which indicated both groups belong to the same assemblage.This assemblage is clearly isolated as a deep-branching clade and invariably positioned between Euplotida and Hypotricha.The sister group relationship of the Pseudoamphisiellidae and Discocephalidae supports the previous suggestion that they might represent an ordinal taxon,the Discocephalida.Both morphological and morphogenetic features indicate that the pseudoamphisiellids should be placed in the order Discocephalida but as a sister group to other typical discocephalids.Thus we propose establishing a new suborder,Pseudoamphisiellina subord.n.The new taxon is diagnosed by the following characteristics:(i) two distantly separated midventral rows that are morphogenetically formed with an urostylid mode;(ii) absence of the "frontoterminal row",which is formed from the posterior-most frontoventral-transverse cirral anlage in all other typical urostylids;(iii) numerous caudal cirri that derive from each of the dorsal kinety anlagen;(iv) right marginal row that has a unique de novo origin;and (v) inhabiting periphytic communities.The validity of the suborder Pseudoamphisiellina is firmly supported by molecular data. 展开更多
关键词 CILIOPHORA Discocephalida Pseudoamphisiellina subord n. new suborder phylogeny SSU rRNA gene
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Quantum theory on protein folding 被引量:4
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作者 LUO LiaoFu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第3期458-468,共11页
The conformational change of biological macromolecule is investigated from the point of quantum transition.A quantum theory on protein folding is proposed.Compared with other dynamical variables such as mobile electro... The conformational change of biological macromolecule is investigated from the point of quantum transition.A quantum theory on protein folding is proposed.Compared with other dynamical variables such as mobile electrons,chemical bonds and stretching-bending vibrations the molecular torsion has the lowest energy and can be looked as the slow variable of the system.Simultaneously,from the multi-minima property of torsion potential the local conformational states are well defined.Following the idea that the slow variables slave the fast ones and using the nonadiabaticity operator method we deduce the Hamiltonian describing conformational change.It is shown that the influence of fast variables on the macromolecule can fully be taken into account through a phase transformation of slow variable wave function.Starting from the conformation-transition Hamiltonian the nonradiative matrix element was calculated and a general formulas for protein folding rate was deduced.The analytical form of the formula was utilized to study the temperature dependence of protein folding rate and the curious non-Arrhenius temperature relation was interpreted.By using temperature dependence data the multi-torsion correlation was studied.The decoherence time of quantum torsion state is estimated.The proposed folding rate formula gives a unifying approach for the study of a large class problems of biological conformational change. 展开更多
关键词 conformational change of macromolecule quantum transition torsion potential slow variable nonadiabaticity opera-tor Berry's phase quantum decoherence time protein folding
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