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1.
植物有效利用土壤磷特性的遗传学研究进展   总被引:9,自引:0,他引:9  
植物有效利用土壤磷的特性是一系列形态、生理、生化特性的综合反映,包括植物根系活化土壤中难溶性磷、对磷的吸收、转运、分配与利用等。而这些特性又均受控于特定的遗传机制。本文简要概述该特性的细胞遗传学、数量遗传学的研究进展。  相似文献   

2.
荷叶铁线蕨为三峡库区珍稀濒危植物 ,已被国家列为二级保护植物。本文较系统地综述了荷叶铁线蕨的生物学特性 ,包括其形态特征、生长特性、地理分布、生态学特性和群落学特性 ,分析了荷叶铁线蕨濒危的可能原因 ,并提出了保护措施  相似文献   

3.
[目的]对从酸马奶中分离出来的10株乳酸菌进行鉴定和生理生化特性研究,为工业生产筛选特性优良的菌种.[方法]通过形态学观察、生理生化特性、分子生物学特性及其对致病菌抑制作用的研究对其进行鉴定,并筛选特性优良菌株.[结果]10株乳酸菌分别为2株Lactobacillus plantarum、2株Enterococcus villorum、2株Enterococcus dispar、3株Enterococcus durans和1株Enterococcus raffinosus;其对Staphylococcus aureus、Escherichia coli和Enteritidis bacillus有不同程度的抑制作用.[结论]菌株HZ24、HZ25具有良好的生物学特性和益生功能,可以应用到食品发酵工业生产中.  相似文献   

4.
对我国特有的珍稀濒危植物独叶草的生物学特性,包括其形态特征、生长特性、生境特点、群落学特性和地理分布进行了较系统的综述,分析了独叶草濒危的可能原因,并提出了一些保护措施.  相似文献   

5.
太子参生物学特性的研究   总被引:5,自引:0,他引:5  
报道了江苏地道药材太子参Pseudostellaria heterophylla (Miq.)Pax ex Pax et Hoffm的生物学特性,包括形态特征、主要分布区和主产区、生态特性、种子萌发特性、生长发育特性等,为进行太子参的规范化栽培提供科学依据。  相似文献   

6.
【背景】鄂尔多斯地区传统自然发酵苦菜风味和作用独特,但目前尚无关于发酵苦菜中乳酸菌种类及其生物学特性研究的报道。【目的】获得适用于工业化生产特性优良的乳酸菌。【方法】通过测定总酸度筛选高产酸菌株,并进行形态学鉴定、生理生化特性研究,以及16S rRNA基因片段分析。【结果】经鉴定5株高产酸的菌株均为植物乳杆菌,生长温度范围宽,并且具有耐酸、耐碱、耐盐、耐热的特性。【结论】试验菌株具有优良的生理特性和潜在的益生特性,可用于食品工业的生产。  相似文献   

7.
干旱胁迫对植物气孔特性影响研究进展   总被引:5,自引:0,他引:5  
综述干旱胁迫对植物叶片气孔特性的影响,从气孔大小、气孔密度、气孔导度等方面概括植物气孔对干旱胁迫的响应,分析植物气孔特性与其抗旱性的关系,并对气孔特性的研究方向进行展望。  相似文献   

8.
葡激酶的研究进展   总被引:1,自引:0,他引:1  
本文综述了葡激酶的生化特性、溶栓特性、免疫原性和临床应用方面的研究进展。  相似文献   

9.
芽用绿豆品种子粒性状及其豆芽生理特性研究   总被引:1,自引:0,他引:1  
以21份芽用绿豆品种为材料,研究了种皮色泽、种皮比重等种皮性状、百粒重等物理特性、发芽期间的生物产量变化规律、种子吸水速率等生理特性以及绿豆芽产量、豆芽形态特征和感官品质等芽用特性指标,分析了各项物理生理特性指标与芽用特性指标的相关性。结果表明,芽用绿豆品种的产出比、下胚轴粗和下胚轴长等特性指标范围分别为111.7-143.2、7.21-11.79和0.245-0.353;品种的种皮色泽与绿豆芽生物产量、绿豆芽下胚轴粗及下胚轴长无显著相关,而与品种的百粒重呈显著相关性(P<0.05);百粒重与绿豆芽生物产量呈显著负相关(P<0.05);下胚轴粗与绿豆芽生物产量呈极显著负相关(P<0.05);初步建立了适用于评价绿豆品种芽用特性的指标:豆芽产量、下胚轴粗和下胚轴长,筛选出具有较好芽用特性的绿豆品种MB01、MB07、MB19和MB45。  相似文献   

10.
电磁场曝露对生物组织电磁特性的影响   总被引:3,自引:0,他引:3  
电磁辐射严重影响着人体的健康.电磁场生物效应的发生机制与电磁场本身的特性相关,同时也与生物组织在电磁场作用下电磁特性的改变密切相关.生物体内的信号分子、自由基以及磁颗粒等处于外加电磁场中时其电磁特性会发生变化,尤其是不同频率电磁场曝露作用下生物组织的导电、介电以及磁学等特性会有非常显著的区别.明确不同频率电磁场作用下生物组织电磁特性的变化规律是研究电磁场生物效应发生机制以及预防问题的关键.综述了近年来电磁场对于生物组织电磁特性影响的研究成果,并对未来的研究方向做了展望.  相似文献   

11.
The Cuban species of Calisto are reviewed based on the morphology of adult and immature stages, as well as DNA sequences of six genes (COI, EF1α, wingless, GAPDH, RpS5, CAD). A new species, Calisto occultasp. n., is described from the northeastern Cuban mountains. Calisto smintheus Bates, 1935 and Calisto bruneri, Michener 1949 are revised and revalidated. A new status, the species level, is proposed for Calisto brochei, Torre 1973, Calisto muripetens, Bates 1939 and Calisto bradleyi, Munroe 1950. The immature stages of Calisto smintheus, Calisto brochei,and Calisto occulta are described for the first time, and those of Calisto herophile, Hübner 1823 are redescribed. Useful morphological characters for adults are the shape and conspicuousness of androconial patch, the number and relative size of white dots on underside of hindwing, the shape of aedeagus, the shape of digitiform projection of genitalia valve, the shape and relative size of tegumen and uncus, the relative size of female genitalia, the height of sterigmal ring dorsal crown of the latter, and the relative size of corpus bursae and ductus bursae. For the immature stages, the most important characters are the color pattern of head capsule, the number and width of longitudinal lines of body, in the larvae; and the color pattern and the absence or presence of dorsal ridges on the abdomen of pupae. The phylogenetic relationships between the Cuban Calisto species are quite robust and well-supported; however, conflict between mitochondrial and nuclear datasets was detected in Calisto brochei, Calisto muripetens and to a lesser degree in Calisto bradleyi.  相似文献   

12.
B. A. Manny  D. Kenaga 《Hydrobiologia》1991,219(1):269-279
Despite extensive urbanization of its watershed, the Detroit River still supports diverse fish and wildlife populations. Conflicting uses of the river for waste disposal, water withdrawals, shipping, recreation, and fishing require innovative management. Chemicals added by man to the Detroit River have adversely affected the health and habitats of the river's plants and animals. In 1985, as part of an Upper Great Lakes Connecting Channels Study sponsored by Environment Canada and the U.S. Environmental Protection Agency, researchers exposed healthy bacteria, plankton, benthic macroinvertebrates, fish, and birds to Detroit River sediments and sediment porewater. Negative impacts included genetic mutations in bacteria; death of macroinvertebrates; accumulation of contaminants in insects, clams, fishes, and ducks; and tumor formation in fish. Field surveys showed areas of the river bottom that were otherwise suitable for habitation by a variety of plants and animals were contaminated with chlorinated hydrocarbons and heavy metals and occupied only by pollution-tolerant worms. Destruction of shoreline wetlands and disposal of sewage and toxic substances in the Detroit River have reduced habitat and conflict with basic biological processes, including the sustained production of fish and wildlife. Current regulations do not adequately control pollution loadings. However, remedial actions are being formulated by the U.S. and Canada to restore degraded benthic habitats and eliminate discharges of toxic contaminants into the Detroit River.Contribution 738 of the National Fisheries Research Center-Great Lakes, 1451 Green Road, Ann Arbor, MI 48105, U.S.A.  相似文献   

13.
Nine of 10 genera and 119 of approximately 240 species of the Pinaceae occur in China, including 67 endemic species and two endemic genera. In this paper, the distributional maps of all the genera of the Pinaceae are presented (fig. 1-8). The horizontal and vertical distributions of species in each genus are discussed. The analysis of the distribution patterns of the genera indicates that some genera, such as Keteleeria, Tsuga, Pseudotsuga, Cathaya and Pseudolarix, are restricted to the area south of the Qinling Mountains and the Huaihe River, and the others, i. e. Picea, Abies, Larix and Pinus, extend northward to northeastern China. However, all of the genera except Keteleeria and Pinus are not found in very dry areas and tropical mountainous regions of China. The monotypic genera, Cathaya and Pseudolarix, are distributed in eastern and central China. The genus Keteleeria consists of 10 species, 7 of which are concentrated in southern Guizhou, northern Guangxi, southwestern Hunan and easternmost Yunnan. The distribution of the remaining 6 genera shows the maximum concentration in western Sichuan and northwestern Yunnan. (Figs. 2-8). Furthermore, more than third of species of the Pinaceae (37.8%) are also concentrated in western Sichuan and northwestern Yunnan. where a great variety of habitats and different topographic features occur. It is apparent that to conduct our systematic and evolutionary studies on this family in these region is especially needed. The relations between the areal size and the tolerance of species are discussed. The distributions of macrofossils and microfossils of the genera of the Pinaceae ia China are given, and it has been proved that areas of most genera of the family were considerably larger in the past. than at present.  相似文献   

14.
The Hierarchical Taxonomy of Psychopathology (HiTOP) is a scientific effort to address shortcomings of traditional mental disorder diagnoses, which suffer from arbitrary boundaries between psychopathology and normality, frequent disorder co‐occurrence, heterogeneity within disorders, and diagnostic instability. This paper synthesizes evidence on the validity and utility of the thought disorder and detachment spectra of HiTOP. These spectra are composed of symptoms and maladaptive traits currently subsumed within schizophrenia, other psychotic disorders, and schizotypal, paranoid and schizoid personality disorders. Thought disorder ranges from normal reality testing, to maladaptive trait psychoticism, to hallucinations and delusions. Detachment ranges from introversion, to maladaptive detachment, to blunted affect and avolition. Extensive evidence supports the validity of thought disorder and detachment spectra, as each spectrum reflects common genetics, environmental risk factors, childhood antecedents, cognitive abnormalities, neural alterations, biomarkers, and treatment response. Some of these characteristics are specific to one spectrum and others are shared, suggesting the existence of an overarching psychosis superspectrum. Further research is needed to extend this model, such as clarifying whether mania and dissociation belong to thought disorder, and explicating processes that drive development of the spectra and their subdimensions. Compared to traditional diagnoses, the thought disorder and detachment spectra demonstrated substantially improved utility: greater reliability, larger explanatory and predictive power, and higher acceptability to clinicians. Validated measures are available to implement the system in practice. The more informative, reliable and valid characterization of psychosis‐related psychopathology offered by HiTOP can make diagnosis more useful for research and clinical care.  相似文献   

15.
The development of new taxonomical theories and approaches, particularly molecular phylogenetics, has led to the expansion of traditional morphology-based taxonomy into the concept of "integrative taxonomy." Taxonomic knowledge has assumed greater significance in recent years, particularly because of growing concerns over the looming biodiversity crisis. Since its establishment in 1938, the Kunming Institute of Botany (KIB), which is located in Yunnan province in Southwest China, has focused attention on the taxonomy and conservation of the flora of China. For the forthcoming 80th anniversary of KIB, we review the achievements of researchers at KIB and their associates with respect to the taxonomy of land plants, fungi, and lichen. Major taxonomic advances are summarized for families of Calymperaceae, Cryphaeaceae, Lembophyllaceae, Neckeraceae, Polytrichaceae and Pottiaceae of mosses, Pteridaceae and Polypodiaceae of ferns, Taxaceae and Cycadaceae of gymnosperms, Asteraceae, Begoniaceae, Ericaceae, Euphorbiaceae, Gesneriaceae, Lamiaceae, Orchidaceae, Orobanchaceae, Poaceae, Theaceae and Urticaceae of angiosperms, Agaricaceae, Amanitaceae, Boletaceae, Cantharellaceae, Physalacriaceae Russulaceae, Suillaceae and Tuberaceae of fungi, and Ophioparmaceae and Parmeliaceae of lichens. Regarding the future development of taxonomy at KIB, we recommend that taxonomists continue to explore the biodiversity of China, integrate new theories and technologies with traditional taxonomic approaches, and engage in creative monographic work, with support from institutions, funding agencies, and the public.  相似文献   

16.
A key is presented for use in identifying asymmetrically winged fruits (samaras) with either proximal or distal locules. It aids identification based on dispersed fuit morphology and can be used to identify undetermined extant herbarium specimens or fossil fruits to the correct extant family and genus. The 39 genera from 11 families (Aceraceae, Anacardiaceae, Fabaceae, Malpighiaceae, Phytolaccaceae, Polygalaceae, Polygonaceae, Rutaceae, Sapindaceae, Trigoniaceae, Ulmaceae) are distinguished on the basis of wing venation, size of fruit, presence and position of attachment surface, presence and type of subsidiary wings on the ovary wall. ornamentation, size and shape of the ovary, locule position, shape of locule cross section, style position and ornamentation, distinction between ovary wall and wing, and angle of attachment between individual samaras. The developmental origins of some of these features are discussed.  相似文献   

17.
Numbers of species and genera,endemic genera,extant primitive genera,relationship and distribution patterns of presently living Chenopodiaceae(two subfamilies,12 tribes,and 118 genera)are analyzed and compared for eight distributional areas,namely central Asia,Europe,the Mediterranean region,Africa,North America,South America, Australia and East Asia. The Central Asia,where the number of genera and diversity of taxa are greater than in other areas,appears to be the center of distribution of extant Chenopodiaceae.North America and Australia are two secondary centers of distribution. Eurasia has 11 tribes out of the 12,a total of 70 genera of extant chenopodiaceous plants,and it contains the most primitive genera of every tribe. Archiatriplex of Atripliceae,Hablitzia of Hablitzeae,Corispermum of Corispermeae,Camphorosma of Camphorosmaea,Kalidium of Salicornieae,Polecnemum of Polycnemeae,Alexandra of Suaedeae,and Nanophyton of Salsoleae,are all found in Eurasia,The Beteae is an Eurasian endemic tribe,demonstrating the antiquity of the Chenopodiaceae flora of Eurasia.Hence,Eurasia is likely the place of origin of chenopodiaceous plants. The presence of chenopodiaceous plants is correlated with an arid climate.During the Cretaceous Period,most places of the continent of Eurasia were occupied by the ancient precursor to the Mediterranean,the Tethys Sea.At that time the area of the Tethys Sea had a dry and warm climate.Therefore,primitive Chenopodiaceae were likely present on the beaches of this ancient land.This arid climatic condition resulted in differentiation of the tribes Chenopodieae,Atripliceae,Comphorosmeae,Salicornieae,etc.,the main primitive tribes of the subfamily Cyclolobeae. Then following continental drift and the Laurasian and Gondwanan disintegration, the Chenopodiaceae were brought to every continent to propagate and develop, and experience the vicissitudes of climates, forming the main characteristics and distribution patterns of recent continental floras. The tribes Atripliceae, Chenopodieae, Camphorosmeae, and Salicornieae of recent Chenopodiaceae in Eurasia, North America, South America, southern Africa, and Australia all became strongly differentiated. However, Australia and South America, have no genera of Spirolobeae except for a few maritime Suaeda species. The Salsoleae and Suaedeae have not arrived in Australia and South America, which indicates that the subfamily Spirolobeae developed in Eurasia after Australia separated from the ancient South America-Africa continent, and South America had left Africa. The endemic tribe of North America, the tribe Sarcobateae, has a origin different from the tribes Salsoleae and Suaedeae of the subfamily Spirolobeae. Sarcobateae flowers diverged into unisexuality and absence of bractlets. Clearly they originated in North America after North America had left the Eurasian continent. North America and southern Africa have a few species of Salsola, but none of them have become very much differentiated or developed, so they must have arrived through overland migration across ancient continental connections. India has no southern African Chenopodiaceae floristic components except for a few maritime taxa, which shows that when the Indian subcontinent left Africa in the Triassic period, the Chenopodiaceae had not yet developed in Africa. Therefore, the early Cretaceous Period about 120 million years ago, when the ancient Gondwanan and Laurasian continents disintegrated, could have been the time of origin of Chenopodiaceae plants.The Chinese flora of Chenopodiaceae is a part of Chenopodiaceae flora of central Asia. Cornulaca alaschnica was discovered from Gansu, China, showing that the Chinese Chenopodiaceae flora certainly has contact with the Mediterranean Chenopodiaceae flora. The contact of southeastern China with the Australia Chenopodiaceae flora, however, is very weak.  相似文献   

18.
Chemical basis of inflammation-induced carcinogenesis   总被引:11,自引:0,他引:11  
Chronic inflammation induced by biological, chemical, and physical factors has been associated with increased risk of human cancer at various sites. Inflammation activates a variety of inflammatory cells, which induce and activate several oxidant-generating enzymes such as NADPH oxidase, inducible nitric oxide synthase, myeloperoxidase, and eosinophil peroxidase. These enzymes produce high concentrations of diverse free radicals and oxidants including superoxide anion, nitric oxide, nitroxyl, nitrogen dioxide, hydrogen peroxide, hypochlorous acid, and hypobromous acid, which react with each other to generate other more potent reactive oxygen and nitrogen species such as peroxynitrite. These species can damage DNA, RNA, lipids, and proteins by nitration, oxidation, chlorination, and bromination reactions, leading to increased mutations and altered functions of enzymes and proteins (e.g., activation of oncogene products and/or inhibition of tumor-suppressor proteins) and thus contributing to the multistage carcinogenesis process. Appropriate treatment of inflammation should be explored further for chemoprevention of human cancers.  相似文献   

19.
Athyrisinine brachiopods from the Upper Silurian of Russia and the Lower–Middle Devonian of China and north Vietnam include over 70 species belonging to Athyrisina and Parathyrisina ; generic and subfamilial diagnoses are emended. Five genera are considered synonyms of Athyrisina and three of Parathyrisina . A neotype is selected and illustrated for Athyrisina squamosa , the type species of Athyrisina . Four nomina nova , Athyrisina xui , Parathyrisina wani , P. minima , and P. cheni , are suggested as new substitute names for Athyrisina tumida Wang, in Xu et al. 1978 (primary homonymy), Athyrisinoides ganxiensis Wan, in Xu et al. 1978, Parathyrisina minor Zhang, in Zhang and Fu 1983, and Athyrisinoides tudilingensis Chen, 1979 (secondary homonyms) respectively. A new genus, Bruntosina , is described from the Emsian to Eifelian of the Qinling region. A new subfamily, Homeathyridinae, is erected within the Athyrididae with Homeathyris , Pseudohomeospira , and Squamathyris included, revised and their diagnoses emended. Homeathyris incisus sp. nov. is described from the Ludfordian of Novaya Zemlya. Ikella is revised and excluded from the athyrisinins. The origin and dispersal of the homeathyridins and the athyrisinins are discussed.  相似文献   

20.
【目的】筛选特定条件下麦长管蚜Sitobion avenae稳定表达的微小RNA(miRNA)表达分析内参基因。【方法】根据麦长管蚜miRNA Illumina测序结果筛选出miR-10-3p, miR-993, miR-276, miR-275, miR-252a, miR-1, miR-375, pc-15, pc-73和1个常用内参基因U6共10个候选内参基因。利用qRT-PCR测定10个候选内参基因在麦长管蚜有翅蚜和无翅蚜不同发育时期、不同组织以及4种化学药剂(95.1%吡虫啉原药、97.8%噻虫啉原药、95%阿维菌素原药和40%氧乐果乳油)处理无翅蚜中的相对表达量。利用GeNorm, NormFinder, ΔCt法, BestKeeper和RefFinder对10个候选内参基因的表达稳定性进行评价。【结果】qRT-PCR结果表明,在麦长管蚜有翅蚜不同发育阶段、无翅蚜不同发育阶段、有翅蚜和无翅蚜不同组织中和4种药剂处理的无翅蚜中表达量较高的内参基因分别是miR-276, miR-276, miR-10-3p和miR-10-3p;5种方法综合分析得出,在上述4种条件下表达稳定性都较好的内参基因分别是miR-252a, miR-993, miR-275和miR-993。GeNorm软件分析表明不同条件下麦长管蚜内参基因的较佳数目为2,结合RefFinder稳定性综合排序的结果分析可知在有翅蚜不同发育阶段、无翅蚜不同发育阶段、有翅蚜和无翅蚜不同组织中和不同药剂处理无翅蚜中稳定表达的内参基因组合分别是miR-252a和miR-276, miR-993和miR-276, miR-275和miR-10-3p, miR-993和miR-10-3p。【结论】麦长管蚜有翅蚜不同发育阶段、无翅蚜不同发育阶段、有翅蚜和无翅蚜不同组织中和不同药剂处理无翅蚜中内参基因优化组合分别为miR-252a和miR-276, miR-993和miR-276, miR-275和miR-10-3p, miR-993和miR-10-3p。研究结果为麦长管蚜miRNA基因定量表达的研究提供了内参基因选择的依据。  相似文献   

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