松属细胞学分类和系统演化初探

本文通过对分布于世界6个地区的松属28个种的染色体组型分析和染色体组型分析和染色体臂比模糊聚类分析,结合其地理分布及其它方面资料,探讨了松属的起源,变异及其系统演化的过程,并对松属一些在形态分类上有分歧意见的种,进行了细胞分类的分析,并提出了作者的见解。     

天牛科昆虫的起源探讨

天牛科的起源与演化问题,目前仍有很大争论。本文在前人的基础上,结合多学科,就天牛科及其主要亚科的起源时间进行了研究和论述。结果表明,天牛科的起源至少应追溯到三叠纪中期联合古陆分离之前;各亚科起源的时间顺序应是:沟胫天牛亚科、天牛亚科、锯天牛亚科、花天牛亚科、幽天牛亚科。     

云南地区裸子植物的区系组成及物种多样性分布格局

该研究利用云南地区裸子植物的地理分布信息,探讨了该地区裸子植物的多样性、区系构成及其地理分布格局.结果表明:云南地区共拥有裸子植物106种,分属于32属,10科,是中国裸子植物最丰富的地区.比较重要的科为松科Pinaceae、柏科Cupressaceae、罗汉松科Podocarpaceae和杉科Taxodiaceae;比较重要的属为圆柏属Sa-bina、松属Pinus和罗汉松属Podocarpus.无论是在科还是在属的水平上,云南地区裸子植物区系总体上以温带区系成分为主,表现出强烈的温带区系特征.温带起源的松科、杉科和柏科植物主要分布于云南北部,尤其是滇西北地区,这与喜马拉雅山的抬升作用和相对温凉的环境是一致的.热带起源的罗汉松科、买麻藤科和苏铁科植物主要分布在云南南部地区,这与其相对温暖的环境和稳定的地质历史是一致的.云南地区裸子植物科的种系分化强度的高值主要出现在滇西北地区,这可能与其相对活跃的地质历史和复杂的地形有关.     

松属51个种间的核型进化初探

根据分布于世界６个地区的松属５１个种的核型分析结果和每种松树的染色体长度比以平均臂比绘制了核型演变图．作者认为松属的核型进化趋势是：（１）由对称类型往不对称的类型进化；（２）双线管束亚属是由单维管束亚属演变而来的；（３）松属种间具有一致的起源；（４）白皮松的核型是属于单维管束亚属往及维管束亚属过渡的类型．     

地松鼠亚科的起源与演化研究进展

归纳总结了地松鼠亚科Xerinae的起源和演化研究进展。现生地松鼠种类繁多、地理广布是由陆桥协助祖先类群扩散和生境变化导致祖先类群发生适应性演化共同作用的结果。化石和分子证据都表明地松鼠起源于早渐新世的欧亚大陆。地松鼠起源后很快分化出3支:第1支在19 Ma左右,即非洲—欧亚陆桥第1次连接时扩散到非洲,在缺乏树栖松鼠竞争的情况下演化成现生的非洲树松鼠族Protoxerini;第2支在欧亚大陆向地栖生活演化的同时,部分类群在14 Ma左右扩散到非洲,并演化出非洲地松鼠族Xerini的Xerus和Atlantoxerus;第3支是旱獭族Marmotini的祖先,在欧亚大陆演化出岩松鼠属Sciurotamias的同时,于中渐新世通过白令陆桥扩散到北美,并在北美草原化的大背景下演化出花鼠属Tamias,"黄鼠属"‘Spermophilus’,旱獭属Marmota,土拨鼠属Cynomys等。花鼠属、"黄鼠属"和旱獭属于中新世扩散回欧亚大陆,其中"黄鼠属"和旱獭属在欧亚大陆发生适应性演化。伴随生境变化而发生形态、行为等适应性演化,是地松鼠繁盛的重要原因。演化过程中,旱獭属、土拨鼠属、"黄鼠属"等地栖型松鼠的体型显著增大,尾巴显著变短,而半地栖型和树栖型的体型瘦长,尾巴变长。     

中国芸薹属植物的起源、演化与散布

芸薹属BrassicaL植物在世界上大约有40余种,其中中国有15种。在此,就中国芸薹属植物的起源、演化和扩散问题进行了研究,结果表明:(1)芸薹属植物的起源。通过芸薹属与其外类群白花菜科Capparaceae形态特征的比较,将中国芸薹属植物划分为白菜组SectPekinensis、芥菜组SectJuncea、甘蓝组SectOleracea三个类群,其中白菜组最原始、芥菜组较进化,甘蓝组进化程度最高;(2)芸薹属植物广泛分布于中国的长江、黄河流域及西部山区,但从其现代分布来看,多栽培于青藏高原及其周边地区,笔者认为以青藏高原为主体的西部高山、丘陵地区可能是中国芸薹属植物的分布中心区,并提出中国芸薹属植物是本土起源的,并非来源于地中海地区。(3)通过对中国芸薹属植物分布的分析,笔者推测中国芸薹属植物的散布可能有四条散布途径。第一条是由藏南河谷及横断山脉的北部向西沿青海东部的祁连山以及甘肃的河西走廊,新疆的天山一带,抵达塔里木盆地两侧山地。第二条是由藏南河谷及横断山脉地区向东北方向延伸,经中国甘肃东部、宁夏、陕西北部、山西、河北北部、内蒙古及东北的大、小兴安岭,沿黄河流域及东北三江流域分布。第三条是由藏南河谷及横断山脉地区向东南方向延伸,经四川、云南、重庆、沿长江流域分布,并延伸到广东、台湾一带,第四条是沿藏南河谷及横断山脉向南到达喜马拉雅山南北两侧的干旱河谷。     

玛湖地区构造演化及对玛东斜坡百口泉组油气成藏的影响

为了落实玛湖地区构造演化对玛东斜坡三叠系百口泉组油气成藏的影响,在系统梳理地层厚度、断裂类型以及构造要素组合特征等主要构造特征的基础上,分析了构造演化过程及不同时期的构造运动对百口泉组油气成藏的影响。研究结果如下：(1)玛湖地区构造演化分为5个阶段,石炭纪晚期强烈挤压构造形变阶段;二叠纪早-中期西部隆起逆冲推覆阶段;二叠纪末期-三叠纪早期整体抬升遭受剥蚀阶段;三叠纪-侏罗纪缓慢下降阶段;白垩纪末期掀斜阶段。(2)构造运动对玛东斜坡油气成藏的影响主要包括以下4个方面：控制烃源岩分布;提供油气的垂向输导和横向运移通道;改善储层物性;导致油气逸散和二次聚集。(3)距离断层较近且继承性发育的背斜、鼻状构造等有利构造部位是油气勘探的重要方向。     

横断山区苹果属植物区系地理学研究

 古地中海退却与喜马拉雅－横断山的隆起，对苹果属植物区系的发展具有重要影响。采用系统发生－植物地理学的理论和方法，研究横断山区苹果属植物区系的起源和演化。结果表明，老挝海棠的小果类型通过云南南部河谷流域往北传播到横断山区，由宿萼类型演化成滇池海棠系的种类；由脱萼类型演化成陇东海棠系的种类。横断山区苹果属植物区系演化的特点是历史时期长，种类多，既有种类间小的间断分化，又有组、系间大的间断分化。该区系具有明显的演化中心和辐射状的现代分布格局，揭示了物种间的亲缘关系、空间关系、时间关系等三维关系间的密切联系。横断山区苹果属植物虽然种类多，但不是原始种的分布地，因此该地区是苹果属植物的演化中心，而不是起源中心。     

云南茶组植物的分布

云南既是茶树起源中心,又是茶树演化变异中心.茶组植物在云南有着广泛的分布.本文总结了茶组植物研究成果,明确了云南茶组植物的分布,云南茶组植物种及变种的数量及名称,为茶树资源分类、利用提供参考.     

世界向日葵育种的新发展

向日葵育种和其它作物一样经历了原始的民间选种和现代的科学选种两大历史阶段。在由野生转化为栽培,由低产演化为高产的过程中,经历了漫长的原始人工选择阶段,这个阶段主要是在北美某些地区进行。现代育种,开始于上世纪末和本世纪初,以苏联最著成效。1890年,N·卡尔津首次在观     

A molecular phylogeny for bats illuminates biogeography and the fossil record

Bats make up more than 20% of extant mammals, yet their evolutionary history is largely unknown because of a limited fossil record and conflicting or incomplete phylogenies. Here, we present a highly resolved molecular phylogeny for all extant bat families. Our results support the hypothesis that megabats are nested among four major microbat lineages, which originated in the early Eocene [52 to 50 million years ago (Mya)], coincident with a significant global rise in temperature, increase in plant diversity and abundance, and the zenith of Tertiary insect diversity. Our data suggest that bats originated in Laurasia, possibly in North America, and that three of the major microbat lineages are Laurasian in origin, whereas the fourth is Gondwanan. Combining principles of ghost lineage analysis with molecular divergence dates, we estimate that the bat fossil record underestimates (unrepresented basal branch length, UBBL) first occurrences by, on average, 73% and that the sum of missing fossil history is 61%.     

Podocarpus from the eocene of north america

A few leafy gymnosperm shoots were found in Eocene deposits of southeastern North America. Similar fossil material from Tertiary deposits in North America has been identified as Taxodium, Taxites, and Sequoia. This new fossil material is not related to these genera but belongs to Podocarpus section Stachycarpus. This is the first fossil record of this section in North America.     

Pollen and spores date origin of rift basins from Texas to nova scotia as early late triassic

Palynological studies of the nonmarine Newark Supergroup of eastern North America and of rift basins in the northern Gulf of Mexico facilitate correlation with well-dated marine sections of Europe. New information emphasizes the chronological link between the Newark basins and a Gulf of Mexico basin and their common history in the rifting of North America from Pangea. Shales from the subsurface South Georgia Basin are shown to be of late Karnian age (early Late Triassic). The known time of earliest sedimentation in the Culpeper Basin is extended from Norian (late Late Triassic) to mid-Karnian, and the date of earliest sedimentation in the Richmond and Deep River basins is moved to at least earliest Karnian, perhaps Ladinian. The subsurface Eagle Mills Formation in Texas and Arkansas has been dated palynologically as mid- to late Karnian. The oldest parts of the Newark Supergroup, and the Eagle Mills Formation, mostly began deposition in precursor rift basins that formed in Ladinian to early Karnian time. In the southern Newark basins, sedimentation apparently ceased in late Karnian but continued in the northern basins well into the Jurassic, until genesis of the Atlantic ended basin sedimentation.     

Corrected Late Triassic latitudes for continents adjacent to the North Atlantic

We use a method based on a statistical geomagnetic field model to recognize and correct for inclination error in sedimentary rocks from early Mesozoic rift basins in North America, Greenland, and Europe. The congruence of the corrected sedimentary results and independent data from igneous rocks on a regional scale indicates that a geocentric axial dipole field operated in the Late Triassic. The corrected paleolatitudes indicate a faster poleward drift of approximately 0.6 degrees per million years for this part of Pangea and suggest that the equatorial humid belt in the Late Triassic was about as wide as it is today.     

美洲短叶松（Pinus echinata）引种实验报告

本文总结了永川市阴山林场对短叶松（Ｐｉｎｕｓｅｃｈｉｎａｔａ）引种育苗、造林的实验过程。同时，将马尾松与短叶松进行了同步的对比试验。结果表明，引种是成功的。短叶松不需特殊措施，可在本地正常生长。幼树期间的生长优于马尾松。     

Molecular phylogenetics of mastodon and Tyrannosaurus rex

We report a molecular phylogeny for a nonavian dinosaur, extending our knowledge of trait evolution within nonavian dinosaurs into the macromolecular level of biological organization. Fragments of collagen alpha1(I) and alpha2(I) proteins extracted from fossil bones of Tyrannosaurus rex and Mammut americanum (mastodon) were analyzed with a variety of phylogenetic methods. Despite missing sequence data, the mastodon groups with elephant and the T. rex groups with birds, consistent with predictions based on genetic and morphological data for mastodon and on morphological data for T. rex. Our findings suggest that molecular data from long-extinct organisms may have the potential for resolving relationships at critical areas in the vertebrate evolutionary tree that have, so far, been phylogenetically intractable.     

A devonian tetrapod from north america

An early tetrapod fossil from the Upper Devonian of Pennsylvania (Catskill Formation) extends the temporal range of tetrapods in North America and suggests that they attained a virtually global equatorial distribution by the end of the Devonian. Derived features of the shoulder girdle indicate that appendicular mechanisms of support and propulsion were well developed even in the earliest phases of tetrapod history. The specialized morphology of the pectoral skeleton implies that the diversity of early tetrapods was great and is suggestive of innovative locomotor patterns in the first tetrapods.     

Fecundity-survival trade-offs and parental risk-taking in birds

Life history theory predicts that parents should value their own survival over that of their offspring in species with a higher probability of adult survival and fewer offspring. We report that Southern Hemisphere birds have higher adult survival and smaller clutch sizes than Northern Hemisphere birds. We subsequently manipulated predation risk to adults versus offspring in 10 species that were paired between North and South America on the basis of phylogeny and ecology. As predicted, southern parents responded more strongly to reduce mortality risk to themselves even at a cost to their offspring, whereas northern parents responded more strongly to reduce risk to their offspring even at greater risk to themselves.     

Triassic pollen date moroccan high atlas and the incipient rifting of pangea as middle carnian

Palynomorphs from the High Atlas Mountains south of Marrakech define the Minutosaccus-Patinasporites Concurrent Range Zone, which is time-stratigraphically equivalent to the Swiss and English middle Keuper, type Carnian of Austria, and North American Triassic beds in Virginia, North Carolina, Pennsylvania, New Jersey, Texas, New Mexico, and Arizona, thus dating an early episode of continental rifting between Africa and North America.     

Abrupt uplift within the past 1700 years at southern puget sound, washington

Shorelines rose as much as 7 meters along southern Puget Sound and Hood Canal between 500 and 1700 years ago. Evidence for this uplift consists of elevated wave-cut shore platforms near Seattle and emerged, peat-covered tidal flats as much as 60 kilometers to the southwest. The uplift was too rapid for waves to leave intermediate shorelines on even the best preserved platform. The tidal flats also emerged abruptly; they changed into freshwater swamps and meadows without first becoming tidal marshes. Where uplift was greatest, it adjoined an inferred fault that crosses Puget Sound at Seattle and it probably accompanied reverse slip on that fault 1000 to 1100 years ago. The uplift and probable fault slip show that the crust of the North America plate contains potential sources of damaging earthquakes in the Puget Sound region.