Ferns diversified in the shadow of angiosperms

The rise of angiosperms during the Cretaceous period is often portrayed as coincident with a dramatic drop in the diversity and abundance of many seed-free vascular plant lineages, including ferns. This has led to the widespread belief that ferns, once a principal component of terrestrial ecosystems, succumbed to the ecological predominance of angiosperms and are mostly evolutionary holdovers from the late Palaeozoic/early Mesozoic era. The first appearance of many modern fern genera in the early Tertiary fossil record implies another evolutionary scenario; that is, that the majority of living ferns resulted from a more recent diversification. But a full understanding of trends in fern diversification and evolution using only palaeobotanical evidence is hindered by the poor taxonomic resolution of the fern fossil record in the Cretaceous. Here we report divergence time estimates for ferns and angiosperms based on molecular data, with constraints from a reassessment of the fossil record. We show that polypod ferns (> 80% of living fern species) diversified in the Cretaceous, after angiosperms, suggesting perhaps an ecological opportunistic response to the diversification of angiosperms, as angiosperms came to dominate terrestrial ecosystems.     

佛坪自然保护区蕨类植物地理分布和区系分析

佛坪自然保护区的蕨类植物水平分布与这一地区的森林分布格局是一致的,垂直分布分为４个带谱。该区蕨类植物区系组成共９５种,隶属于２０科４３属。在区系结构上表现出３个特征：①种系密度大,成分多样;②属的地理成分多样,以温带成分为主,兼具热带、亚热带性质;③该区属于“耳蕨—鳞毛蕨植物区系”     

武陵山地区药用蕨类植物资源调查

武陵山地区共有药用蕨类植物41科，80属，214种.调查结果表明，药用蕨类植物在武陵山地区种类丰富，优势类群明显；地理成分复杂，东亚成分突出；地域分布不均，以中低海拔为主；类型众多，疗用广泛.通过对该类植物资源可利用量的估计，该区至少有79种可供直接开发利用，100种根据需要可酌量控制利用，有35种应严加保护.     

南京宁镇山脉南支蕨类植物区系及园林应用

【目的】了解南京宁镇山脉南支蕨类植物区系及生态类型,分析蕨类植物在园林景观配置中的应用型。【方法】以南京将军山为对象,通过野外调查和室内标本鉴定等方法统计出该区蕨类植物种类,分析了该地蕨类植物区系的组成和分布区类型,并将该区系与其他蕨类植物区系的相似性系数、综合系数及物种丰富度进行了比较,最后总结了将军山蕨类植物的生态类型及其园林应用。【结果】南京将军山地区共计有蕨类植物19科24属33种; 区系综合系数为0.442,物种丰富度指数最高,为25.54。该区蕨类植物优势科为金星蕨科,没有明显的优势属,具有古老性和残遗性的特征。将军山蕨类植物区系与浙江龙王山、江苏云台山蕨类植物区系关系近,与安徽黄山、河南高乐山蕨类植物区系关系比较近,与江西庐山蕨类植物区系关系比较疏远。根据蕨类植物的生境和分布,将军山蕨类植物可分为浮水、石生及土生共3种生态类型。【结论】南京将军山蕨类植物区系组成比较丰富,具有热带向温带过渡的特征,东亚分布物种在该区系占有主要优势。该区观赏蕨类植物资源较为丰富,但是许多观赏价值较高并有应用前景的蕨类植物还未被认知和开发利用。     

不同水分条件对3种蕨类植物配子体形态发育的影响

研究了不同水分条件对3种不同演化地位的蕨类植物(海金沙(Lygodium japonicum)、水蕨(Ceratopteris thalictroides)、狗脊(Woodwardia japonica))的配子体形态发育的影响.结果表明:1)随着水分的增加,海金沙、水蕨和狗脊孢子的萌发速率加快,丝状体的长度增长; 2)在缺水条件下,配子体易发育成雄性配子体,而在水分充足条件下,配子体易发育成两性配子体或雌性配子体; 3)次生假根的形态及毛状体的数量等受到水分条件的影响; 4)孢子萌发类型、配子体发育类型及成熟原叶体和毛状体的形态结构是相对稳定的性状,可作为蕨类植物分类鉴定的依据.     

湖南省武陵源区蕨类植物初步研究

报道了湖南省武陵源区蕨类植物255种、85属、37科，对区系特征和垂直分布作了初步分析，并指出对湘西北蕨类有必要作进一步研究，     

Vegetation evolution and its response to climatic change during 3.15–0.67 Ma in deep-sea pollen record from northern South China Sea

In order to study vegetation evolution and environmental change during 3.15-0.67 Ma,a total of 608 pollen samples with an average time resolution of 4 ka has been analyzed from ODP Site 1145(water depth 3175 m),northern South China Sea.The deep-sea sediments(213.62-91.9 m) cover from 3.15 to 0.67 Ma based on micropaleonotological stratigraphy.The characteristic features of the pollen diagram include that,pollen influx rises twice obviously around 2.58 Ma and during 2.0-1.8 Ma,in response to global climatic cooling and winter monsoon enhancement.Before 2.58 Ma,tropical and subtropical vegetation,mainly evergreen Quercus(E) and Altingia,predominated around northern SCS with much more tropical montane conifers and ferns relatively.From 2.58 Ma,temperate vegetation increased obviously,implying climatic cooling and winter monsoon enhancement.Spectral analysis shows that percentage variation in tropical and subtropical taxa has a strong 20 ka procession cycle probably due to the summer monsoon;while pollen influx has 100,41 and 19 ka cycles,indicating the sea level and winter monsoon change response to the ice-sheet variations.     

Molecular phylogeny of European and African Barbus and their West Asian relatives in the Cyprininae (Teleostei: Cypriniformes) and orogenesis of the Qinghai-Tibetan Plateau

The phylogenetic relationships of European and African Barbus and their West Asian relatives in Cyprininae remain largely unresolved. Consequently, little is known about the drivers of their evolution, including the possible association of uplifting of the Qinghai-Tibetan Plateau (QTP) with the early divergence of the subfamily. We use complete sequence data of the mitochondrial DNA gene encoding the protein cytochrome b (Cytb) to hypothesize the phylogeny of 85 species belonging to 47 genera in the Cyprininae plus 6 species from the Leuciscinae. We employ 6 other species from Cypriniformes as outgroup taxa and estimate divergence times. Our results indicate that European Barbus sensu stricto lineage including Aulopyge shares a common ancestor with specialized and highly specialized schizothoracins and the genera Cyprinion and Scaphiodonichtys. The common ancestor appears to have originated in the Qinghai-Tibetan Plateau (QTP) region about 19.4–17.8 Ma. Barbus sensu stricto lineage appears to have originated about 16.6–15.5 Ma. Small to medium sized African Barbus sensu lato appear to have had an Oriental origin about 19.1–15.3 Ma and are closely related to Asian Puntius. West Asian Carasobarbus lineage including large African Barbus sensu lato might have originated about 9.94 Ma, also in Oriental Realm and has a close relationship to Asian Neolissochilus and Tor. The large-sized Barbus sensu lato appear to have diverged from Carasobarbus about 7.7 Ma. Finally, the Cyprininae appear to have radiated rapidly into nine lineages and many sublineages from about 27.8 to 17.8 Ma, close to the time of the second-stage tectonic movements of the QTP. Our analyses provide evidence that the uplifting of the QTP drove early diversification of the Cyprininae. Our extensive sampling of species involving all of the important areas results in clear evolutionary scenario for the Cyprininae.     

贵州贵阳阿哈湖国家湿地公园维管植物区系初步研究

采取野外实地调查和室内分析的方法,得知贵阳阿哈湖国家湿地公园共有维管束植物137科346属582种(包括种以下单位),其中蕨类植物15科18属25种,裸子植物4科9属12种,被子植物118科318属545种,水生维管束植物27科43属56种。蕨类植物科的地理成分中热带、亚热带成分占绝对优势;被子植物科的地理成分也是以热带、亚热带成分为优势,世界广布成分也很多。水生维管束植物地理成分复杂,世界广布成分多。     

FERN SECTION IN CUlZHOU BOTANICAL GARDEN

With the devcioprnent of economics and owing to certain factors of plants themselves,some ferns arc in a dangcrous situation. It is necessary to set up a fern section or fernaripm in Guizhou as a gene pool mainly for subtropical ferns, which can not be replaced by the hcrbariurn or natural preserve. A fern section in Guizhou Botanical Garden has been established, It's composed of a 3-are fern garden,a grccnhouse and a shed. 300 taxa of rems and fern aUics from Guizhou and East, South,North east, and South west patts in China have bccn gathered in recent 5 years. Another 3-year project supported by the National Natural Science Foundation of China (NSFC) is carded on for morc fern introduction. It will be not only for thc conservation of the rare and/or endangered pteridophytes, but as a base for fern researching, teaching, scientific propagating and exploiting.Practice shows that Guiyang, the capital of' Guizhou, is one of the ideal places for fern introduction and conscrvation in China.     

Eocene high grade metamorphism and crustal anatexis in the North Himalaya Gneiss Domes,Southern Tibet

Determination of the timing and geochemical nature of early metamorphic and anatectic events in the Himalayan orogen may provide key insights into the physical and chemical behavior of lower crustal materials during the early stage of tectonic evolution in large-scale collisional belts.The Yardoi gneiss dome is the easternmost dome of the North Himalayan Gneiss Domes(NHGD),and contains three types of amphibolites with distinct mineral assemblage,elemental and radiogenic isotope geochemistry,as well as various types of gneisses.SHRIMP zircon U/Pb analyses on the garnet amphibolite and garnet-bearing biotite granitic gneiss yield ages of nearly peak metamorphism at 45.0±1.0 Ma and 47.6±1.8 Ma,respectively,which are 2 to 4 Ma older than the age for partial melting in migmatitic garnet amphibolite(43.5±1.3 Ma).Available data have demonstrated that ultra-high pressure metamorphism in the Tethyan Himalaya occurred at ～55 Ma,and high amphibolite facies to granulite facies metamorphism at 45 to 47 Ma.In addition,partial melting at thickened crustal conditions occurred at 43.5±1.3 Ma,which led to the formation of high Sr/Y ratios two-mica granites.The high-grade metamorphic rocks in the NHGD may represent the subducted front of the Indian continental lithosphere.In large collisional belts,fertile components in crustal materials could melt and form granitic melts with relatively high Na/K and Sr/Y ratios under thickened crustal conditions,significantly different from those formed by decompressional melting during rapid exhumation.     

Evidences of rapid erosion driven by climate in the Yarlung Zangbo （Tsangpo） Great Canyon, the eastern Himalayan syntaxis

Climate and tectonism are both particularly intense in the Yarlung Zangbo (Tsangpo) Great Canyon in the eastern Himalayan syntaxis,which is characterized by the most rapid landscape evolution of anywhere in the world.Thus,the eastern Himalayan syntaxis is one of the best locations to study the interactions between climate and tectonics.This paper investigates the cooling ages of the Doxong La-Baibung profile using apatite fission track (AFT) dating on 11 bedrock samples at elevations ranging from 4210 to 710 m.There are topographic,climatic,metamorphic,and thermochronological gradients in the profile,providing good conditions to study interactions between climate and tectonics.AFT ages ranged from 4.6±0.6 Ma to 1.7±0.3 Ma,and the mean fission track lengths ranged from 11.0 to 12.4 μm.It was found that the cooling rates revealed by AFT ages increased with decreasing elevation.However,the tendency of the cooling rates revealed by the 40 Ar-39 Ar ages was different from that indicated by the AFT ages.Moreover,for most districts of the eastern Himalayan syntaxis,the compiled AFT age distribution correlates well with the annual average precipitation,indicating the coupling of the cooling and erosion rates of the near-surface rock and precipitation.The geothermal history modeling results indicate an obvious increase in the cooling and erosion rate between 1.0 and 0.5 Ma.This age is consistent with other research findings for this time,when the vapor channel of the Yarlung Zangbo Great Canyon began to take effect.These evidences suggest that climate,especially precipitation,has acting as a key factor influencing the rapid cooling and erosion in the Yarlung Zangbo Great Canyon since 1-0.5 Ma.     

Middle-Miocene transformation of tectonic regime in the Himalayan orogen

Understanding the multiple tectonic transformations during the Himalayan orogeny is significant in evaluating the evolution of Himalayan orogen.In the Gyirong area in south Tibet,deformed leucogranitic veins in the biotite-plagioclase gneisses of Greater Himalayan crystalline complex(GHC) constitute south-vergent asymmetric folds.The reconstruction of the veins shows that they experienced two generations of deformation under different tectonic regimes:an earlier top-to-north extension and a later top-to-south thrusting,implying a tectonic transformation from N-S extension to N-S shortening.Zircons LA-ICP-MS U-Pb dating of the leucogranite shows that it was emplaced during 21.03-18.7 Ma.The data suggest that the tectonic transformation occurred after 18.7 Ma.The chronological data of South Tibet detachment system(STDS) and North-South trending rift(NSTR) from Gyirong and other areas indicate that the Himalayan orogeny was in a period of tectonic transformation from N-S extension to N-S shortening during 19-13 Ma.The transformation of tectonic regime was probably controlled by the India-Asia convergence rate.An increase in the convergence rate resulted in N-S shortening of the orogen,thrusting and folding,with coeval formation of the NSTR in Tibet.A decrease in the convergence rate led to N-S extension and reactivation of the STDS.     

山西产13种蕨类植物叶表皮特征的观察

利用光学显微镜对山西产8个科13个种的蕨类植物成熟叶片的叶表皮特征进行了比较观察．结果表明，气孔器类型有7种，为无规则四细胞型，不定细胞型，不等细胞型，横列型，极细胞型，双不等细胞型和腋细胞型．表皮细胞形状不规则或多角(边)形。     

U-Pb ages of Kude and Sajia leucogranites in Sajia dome from North Himalaya and their geological implications

~~U-Pb ages of Kude and Sajia leucogranites in Sajia dome from North Himalaya and their geological implications~~ FallMeetingSuppl.Abstr.,2001,0830h. 10.Lee,J.,Hacker,B.R.,Dinklage,W.S. et al.,Evolution of theKangmarDome, southernTibet:Structural, petrologic, and ther- mochronologic constraints,Tectonics,2000,19:872—895. 11.Parrish,R.R.,Roddick,J.C.,Loveridge,W.D. et al.,Ura- nium-lead analytical techniques at the geochronology laboratory,GeologicalSurvey ofCanada,Geol.Sur…     

Pteridophyte Resources and Their Protection in Guizhou, China

Pteridophte resources are rich in Guizhou, China. More than 700 species, belonging to 150 genera and 53 families, have been known so far Many of them are of edible, medicinal and ornamental value, and the rare and endemic species attract pteridologists being engaged in their research. Pteridophyte protection is much necessary and natural reserves provide an efficient method for most of them in Guizhou. For better study and use, the establishment of special fern section or garden is of significance. A project of setting up a fern section in Guizhou Botanioal Garden is being carried out. It is hopeful that it will be one of the ideal bases as a gone pool of subtropical ferns in China.     

Flabellariopteris,a new aquatic fern leaf from the Late Triassic of western Liaoning,China

An aquatic fern leaf, Flabellariopteris mii Sun gen. et sp. nov. from the Late Triassic of Western Liaoning, China, is described and proposed as the type species of the new morphortaxon of the Marsileaceae. The fossil leaves are preserved as impression. No fertile and rhizomatic materials are found. The leaves attached at a common point on the top of the petiole are composed of two leaflets joined basally in an opposite arrangement. The petiole is slender. The leaflet is fan-shaped or semi-circular, and commonly divided into four wedge-shaped lobes. Terminal margin of lobes is usually incised, incisions shallow or deep, with bluntly rounded or notched apex. The veins are conspicu- ously dichotomous, but anastomoses and marginal vein are absent. The unique morphological features, including two- parted thin leaflets, size, shape, veins and slender petiole, indicate that the present specimen represents an aquatic fern, which is the oldest fossil record and the first megafossil evidence assignable to Marsileaceae from the Triassic floras.     

32种云南蕨类植物中的总黄酮测定

 采用分光光度法,以芦丁为标准品,对32种云南蕨类植物中总黄酮进行了测定.结果表明:所研究的32种云南蕨类植物中均含有黄酮类化合物,而且其中18种植物的总黄酮质量分数超过3%,总黄酮质量分数低于1%的仅有6种,表明蕨类植物是黄酮类化合物的极好资源,有待进一步开发利用.     

Late Paleozoic magmatism in South China:Oceanic subduction or intracontinental orogeny?

A gneissic granite with an U-Pb age of 313±4 Ma was found in northeastern Fujian Province,South China.It is an S-type granite characterized by high K2O,Al2O3 and low SiO2,Na2O contents with high A/CNK ratio of 1.22 for the whole rock.Zircons with stubby morphology from the gneissic granite yield 206 Pb/238 U ages ranging from 326 to 301 Ma with a weighted average age of 313±4 Ma,and negative εHf(t) values from -8.35 to -1.74 with Hf model ages (TCDM) of 1.43 to 1.84 Ga.This S-type granite probably originated from late Paleoproterozoic crust in intracontinental orogeny.Integrated with previous results on paleogeographic reconstruction of South China,the nature of Paleozoic basins,Early Permian volcanism and U-Pb-Hf isotope of detrital zircons from the late Paleozoic to early Mesozoic sedimentary rocks,we suggest the occurrence of a late Paleozoic orogeny in the eastern Cathaysia Block,South China.This orogenic cycle includes Late Carboniferous (340-310 Ma) orogeny (compression) episode and Early Permian (287-270 Ma) post-orogenic or intraplate extension episode.Therefore,the late Paleozoic magmatism in the southeastern South China probably occurred during the intraplate orogeny rather than the arc-related process.