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1.
几种藓类植物挥发油的初步分析   总被引:4,自引:1,他引:3  
利用美国产FINNIGANMAT4510型色质联用仪对三种藓类植物,即厚角绢藓(Entodonconcinnus)、山羽藓(Abietinelaabietina)和毛梳藓(Ptiliumcristacastrensis)进行了挥发油成分的分析,指出了含量较高的化合物成分  相似文献   

2.
从金发藓的化学成分、抗肿瘤活性和抑癌机制等方面对国内外金发藓属植物研究的现状进行了综述.已有研究表明,在金发藓属(Polytrichumspp.)植物中分离得到苯并萘并呫吨酮类化合物及其衍生物、苯乙烯醛基并联苄化合物和苯乙烯基并二氢黄酮类化合物等具有新颖结构骨架的化合物,药理活性分析显示这些新化合物对体外培养的多种肿瘤细胞(如:A-549人肺癌细胞、HepG2人肝癌细胞、MCF-7人乳腺癌细胞等)均具有一定的细胞毒性,并能显著抑制白血病细胞(6T-CEM人T细胞白血病细胞和小鼠P388、L1210白血病细胞)的增殖.其作用机制可能与线粒体功能损伤、活性氧失衡、细胞周期阻滞、破坏细胞膜及诱导凋亡相关.未来可从化学结构与抗肿瘤活性的构效关系、在体抑癌效果、药物代谢、抗肿瘤机制等方面展开深入研究.  相似文献   

3.
回心草化学成分的研究   总被引:14,自引:0,他引:14  
自云南省大理州产的大叶藓属植物回心草中分离出8个化合物。经鉴定,分别为三十三碳烷、棕榈酸、木栓酮、表木栓醇、菜子甾醇、菜油甾醇、豆甾醇及β-谷甾醇。  相似文献   

4.
植物类异戊二烯生物合成相关酶基因研究进展   总被引:6,自引:0,他引:6  
类异戊二烯化合物是自然界广泛存在的一大类天然化合物,具有重要的生物学功能及经济价值.在植物体内,类异戊二烯化合物的生物合成主要有2条代谢途径:甲羟戊酸(MVA)途径和2-甲基-D-赤藓糖醇-4-磷酸(MEP)途径.综述了国内外对植物中这2条代谢途径中相关酶基因的功能、分离情况、表达特性,以及2条代谢途径之间中间产物的交换等方面的研究进展.  相似文献   

5.
分析陕西子午岭自然保护区藓类植物区系组成及分布类型。采用野外采集和室内鉴定的方法。发现子午岭自然保护区共有藓类植物15科41属92种(包括1变种、1变型),其中青藓科、丛藓科、真藓科、羽藓科以及绢藓科5个科为优势科;青藓属、扭口藓属、绢藓属、羽藓属、牛舌藓属、真藓属6个属为优势属,同时具有较多的科中仅1属和属中仅1种的类群。该保护区区系的地理成分中,北温带成分占绝对优势,东亚成分第二,中国特有分布位于第三。区系成分较为丰富,具备华北区藓类植物的典型特征,具有强烈的北温带性质,兼有多种成分。也体现出该区藓类植物区系南北过渡和东西交汇的特征。是陕西省境内一个区系地理成分较为复杂的地区。  相似文献   

6.
以丘间种喙叶泥炭藓(Sphagnum fallax)和丘上种尖叶泥炭藓(S.capillifolium)与大泥炭藓(S.palustre)为材料,研究水位和竞争对泥炭地3种苔藓植物生长的影响.在单种群中,增加水位仅对尖叶泥炭藓生长不利,喙叶泥炭藓和大泥炭藓的高度生长和水平扩展均随水位增加而增加.在混合群中,喙叶泥炭藓的高度生长与盖度扩展主要受水位影响,邻体均未抑制其盖度增长,随着水位增高其盖度逐渐增大;水位影响大泥炭藓的高度生长,两种邻体均导致其盖度降低;除能降低大泥炭藓盖度外,尖叶泥炭藓对邻体和水位均无响应.由此反映出3种苔藓植物存在较为清晰的竞争等级:喙叶泥炭藓竞争能力强于两种丘上种,尖叶泥炭藓次之,大泥炭藓最弱.  相似文献   

7.
吴玉环  高谦  曹同 《贵州科学》2001,19(4):68-77
作者在对国内外 2 1个主要苔藓植物标本馆的有关中国柳叶藓科Amblystegiaceae的 3,0 0 0余份标本 ,包括 4 9份模式标本 ,全面系统的形态解剖学和分类学研究的基础上 ,采用等级聚类分析方法 ,对其属种间的系统关系进行数值分类分析。数值分类分析结果支持了近年来对柳叶藓科植物修订的某些属的概念 :传统上定义很广的细湿藓属和水灰藓属不是一个很自然的分类类群 ,柳叶藓属、湿柳藓属和薄网藓属可以同归于柳叶藓属 ,适合将毛叶镰刀藓归并入范氏藓属中  相似文献   

8.
报道了产自花坪的广西藓类植物31个新记录种,其中,灰藓科(Hypnaceae)有4属9种,羽藓科(Thuidiaceae)有2属5种,蔓藓科(Meteoriaceae)、青藓科(Brachytheciaceae)、薄罗藓科(Leskeaceae)和丛藓科(Pottiaceae)均有2属3种,提灯藓科(Mniaceae)有2属2种,锦藓科(Sematophyllaceae)、孔雀藓科(Hypopterygiaceae)和短颈藓科(Diphysciaceae)均有1新记录种;在19个属中,鹤嘴藓属(Pelekium)和长灰藓属(Herzogiella)为广西新记录属.  相似文献   

9.
萜类化合物是松科(Pinaceae)植物中重要的代谢物,它们与松科植物生长发育、信息传递、气候适应和化学防御等关系密切,在植物生理和生态等方面具有重要功能.松科植物萜类化合物还广泛应用在制药、生物燃料以及合成化学等工业领域,具有重要的经济价值.松科植物通过甲羟戊酸途径和甲基赤藓糖磷酸途径合成所有萜类物质合成所必需的5碳...  相似文献   

10.
河南薄罗藓科植物分布新记录   总被引:2,自引:0,他引:2  
首次报道了河南薄罗藓科(Leskeaceae)5个新记录属,7个新记录种。新记录属分别为:细罗藓属(Leskeella),细枝藓属(Lindbergia),假细罗藓属(Pseudoleskeella),拟草藓属(Pseudoleskeopsis),多毛藓属(Lescuraea);新记录种为:细罗藓(Leskeellanervosa),细枝藓(Lindbergiabrachyptera),中华细枝藓(Lindbergiasinensis),疣齿细枝藓(Lindbergiaaustinii),瓦叶假细罗藓(Pseudoleskeellatectorum),拟草藓(Pseudoleskeopsiszippelii),弯叶多毛藓(Lescuraeaincurvata)。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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