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1.
本文研究的四射珊瑚除少数复体外,其余都属小型单体珊瑚,共8属、15种,其中1新属、11新种。讨论了Paracaninia 一属的特征,发现其时代延至晚二叠世。Plerophyllum 一属的时代应为二叠纪,并讨论了产Plerophyllum differentiatum Iljina 的地层的时代亦应属晚二叠世。  相似文献   

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本文描述和图解介形类化石10属、4亚属和14种,包括1新属(Paraulrichia)和6新种。其中古足目类8属、3亚属和12种;豆石目类1属、1亚属和1种;显壳亚目类1属和1种。这些介形类化石分别采自云南宁蒗大槽子泥盆系剖面大槽子组和碳山坪组。根据介形类组合特征,大槽子组的地质时代为晚埃姆斯期,碳山坪组下、中部的地质时代可能属晚埃姆斯期。介形类生态组合属古足目-平足目集群,代表局限的碳酸盐台地环境。在生物地理上,与泥盆纪华南介形类动物地理区系一致。  相似文献   

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松辽盆地南部沙河子组和泉头组介形类   总被引:4,自引:1,他引:3  
本文首次报道松辽盆地南部内蒙古科尔沁左翼后旗金宝屯地区沙河子组和泉头组下部非海相介形类11属26种,其中沙河子组6属10种,泉头组下部8属18种(包括6新种和1新亚种)。沙河子组以Cypridea(Cypridea) unicostata-C.(Yumenia) casta-Limnocypridea abscondida为代表的介形类化石组合,时代属早白垩世早中期;泉头组下部以Cypridea(Pseudocypridina),limpida C.(Cypridea) albidula seclucarinalis-Paracandona planiuscula为代表的组合,时代为早白垩世晚期。  相似文献   

4.
吐鲁番-哈密盆地早二叠世晚期植物群   总被引:2,自引:1,他引:2  
首次记述了吐鲁番-哈密盆地的早二叠世晚期植物11属13种(包括4新种和4未定种),这是一个以科达类及其相关属为主的安加拉植物群。典型的安加拉植物Vojnovskya属的发现,不但在时代的判定上,而且在植物地理区划上都具重要意义。文中还对这一植物群的特征和时代问题作了简要讨论。  相似文献   

5.
四川盆地南部重庆合川炭坝剖面须家河组中发现丰富的孢粉化石,共计73属150种,其中包括蕨类植物孢子41属89种,裸子植物花粉29属56种,苔藓植物孢子1属3种,藻类化石2属2种。建立一个孢粉组合,命名为Dictyophyllidites-Lunzisporites-Chasmatosporites组合(简称DLC组合),并进一步分为下亚组合和上亚组合。根据孢粉组合内一些重要分子的地质时代延限及与国内外有关孢粉组合的对比,确定其地质时代为晚三叠世晚期,相当于诺利期—瑞替期(Norian—Rhaetian),并且倾向于瑞替期(Rhaetian)。  相似文献   

6.
四川盆地南部重庆合川炭坝剖面须家河组中发现丰富的孢粉化石,共计73属150种,其中包括蕨类植物孢子41属89种,裸子植物花粉29属56种,苔藓植物孢子1属3种,藻类化石2属2种。建立一个孢粉组合,命名为Dictyophyllidites-Lunzisporites-Chasmatosporites组合(简称DLC组合),并进一步分为下亚组合和上亚组合。根据孢粉组合内一些重要分子的地质时代延限及与国内外有关孢粉组合的对比,确定其地质时代为晚三叠世晚期,相当于诺利期—瑞替期(Norian—Rhaetian),并且倾向于瑞替期(Rhaetian)。  相似文献   

7.
塔里木盆地北缘三叠纪孢粉组合   总被引:12,自引:0,他引:12  
刘兆生 《古生物学报》1999,38(4):474-504
研究区发现孢粉化石90属197种,藻类化石2属4种,疑源类2属2种。建立三叠纪的孢粉组合序列,并详细地讨论了各个组合的地质时代。根据孢粉组合反映的植物群面貌,探讨盆地北缘三叠纪的古植被和古气候。  相似文献   

8.
结合新采集的材料与前人研究,综合分析拉萨地块申扎永珠乡下拉组中类动物群的构成与时代,并将其与同期华南类动物群进行对比。分析结果表明,申扎下拉组的类动物群共16属(含1亚属,2存疑属),70种(含比较种与未定种),时代为茅口期,大致相当于Roadian阶上部至Wordian阶。与同期华夏区华南的类动物群相比,下拉组的类动物群在属种构成,尤其是优势类群方面差异显著,其主要特征为Neoschwagerinidae与Verbeekinidae两科的种级分异度很低,Chusenella与Nankinella占优势地位,且缺失了约60%华南的常见属。  相似文献   

9.
本文记述的是湖口兽属的一头骨化石,代表了该属的一个新种。湖口兽属是踝节目的成员,化石最早发现在广东省南雄县湖口公社,所在地层时代是中古新世。  相似文献   

10.
报道产自新疆天山南麓轮台县吐克尔明地区第三系苏维依组的5属10种介形类化石和2属5种轮藻化石,并讲座其地质时代和上、下第三系的界线。  相似文献   

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Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.  相似文献   

13.
正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases  相似文献   

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The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.  相似文献   

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Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.
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正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various  相似文献   

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