桂林漓江沿岸植物区系特点及其与景观的关系

桂林漓江沿岸原生植被受破坏严重 ,植物区系为次生性质 ,其特点 :( 1 )种类丰富 ,共有野生维管束植物 80 8种 ,隶属于 1 5 6科、483属 ;( 2 )植物区系的地理成份复杂 ,可将 45 4个种子植物属归为 1 4个类型 ,以热带、亚热带类型为主 ,温带类型次之 ,中国特有属 6个 ;( 3 )植物区系岩溶特性明显 ,属于东亚植物区、中国—日本森林植物亚区、岭南山地地区的一个小区。植物景观是桂林漓江沿岸风景的重要组成部分 ,具体表现在各类植物群落的外貌和一些重要植物种类的花、果和叶色的季节性变化上。现存的主要植物群落以次生藤刺灌丛为主 ;少见尚存的喀斯特常绿、落叶阔叶混交林 ;独有的喀斯特硬叶常绿阔叶林 :以乌冈栎为建群种的山顶矮林 ,是我国东部湿润亚热带地区罕见的残遗植被类型 ,在构成景观和科研上均有特殊意义。沿河岸分布的植物是最吸引游人注意的重要景观 ,形状各异的灌丛、杂木林、竹林和农田植被等都是风景的重要组成部分     

冉家路口旧石器遗址初步研究

冉家路口遗址位于重庆市丰都县境内,是三峡地区一处重要的旧石器时代遗址。遗址埋藏于长江干流的第Ⅲ级基座阶地底部,石制品经过了短距离的搬运和扰动。2001年进行的第2次发掘揭露面积500m^2,出土石制品680件,类型包括石核、石片、断块和石器等,原料全部就地选取河滩砾石,以锤击法生产石片。石器以大型和中型为主,砍砸器和刮削器是主要类型,其它有凹缺器、薄刃斧、手镐、两面器和石球等;石器毛坯以石片为主,占80．5％;石器采用锤击法加工,以单向加工为主,另外有少数错向和双面加工,器型比较稳定;石器类型具有中国南方旧石器时代主工业的特点,同时呈现较强的石片工业特点。地貌对比和光释光测年结果表明,冉家路口遗址的时代处于中更新世晚期,属旧石器时代中期文化。     

海南岛早志留世晚期腕足类Xinanospirifer的发现--兼论南好组

海南岛保亭县毛感乡南兵至南好公路边南好组以往被确认为下石炭统岩关阶 ,并认为与其下的上志留统足赛岭组呈角度不整合接触。著者最近在该剖面南好组中发现兰多维列世特里奇期晚期 (LateTelychian)Xi nanospirifer腕足动物群和三叶虫Latiproetuscf.latilimbatus,证明久归于下石炭统岩关阶南好组的地质时代应改归于早志留世 (Llandoverian) ;海南岛地区在早志留世明显属于扬子地台区的范畴 ;从地质时间上还暗示南好组与其下伏的足赛岭组不可能存在角度不整合接触 ;     

北京地区均翅亚目昆虫的生态分布

调查发现北京地区现分布蜻蜓目均翅亚目昆虫 3科 1 0种 ,其中科的蓝纹与二色异痣为优势种 ,分布最为广泛 ,通过主成分分析 ,湿地内的浮水层植物盖度、挺水层植物盖度、周围植被盖度及沉水层植物盖度是影响它们分布的最主要生态因子 ,各因子的贡献率分别为 3 0 49,2 4 1 4,1 7 45和1 5 2 6%。色科黑色和透顶单脉色主要分布于北京西南部地区及北部山区水流较快、水体较浅、污染度较小的水域。长叶异痣、七条和白扇主要分布在河流和水库湖泊的边缘地带 ,数量相对较少。烟翅绿色、红痣绿色及白狭扇仅在山区发现 ,分布范围较为狭窄。     

Shell growth of the golden mussel, Limnoperna fortunei (Dunker, 1857) (Mytilidae), in the Río de la Plata, Argentina

The golden mussel, Limnoperna fortunei, is an invasive freshwater bivalve. Since its introduction to Argentina, it had caused damage to the native fauna as well as economic damage to industries of the region. Here, we describe the growth of L. fortunei in a natural temperate environment in Argentina. Age was estimated according to the modal progression method. The constants in the von Bertalanffy growth model were adjusted by an iterative algorithm. Three annual cohorts had similar growth rates. The estimated t ₀ for each cohort showed a temporary displacement in relation to the spawning period.     

Dark Dune Spots: Possible Biomarkers on Mars?

Dark Dune Spots (DDSs) are transitional geomorphologic formations in the frost-covered polar regions of Mars. Our analysis of the transformations and arrangements of subsequent stages of DDSs into time sequence revealed their: (i) hole-like characteristics,(ii) development and formation from the bottom of the frosted layer till the disapperance of the latter, (iii) repeated (seasonal and annual) appearance in a pattern of multiple DDSs on the surface, and (iv) probable origin. We focused our studies on a model in which DDSs were interpreted as objects triggered by biological activity involvedin the frosting and melting processes. We discuss two competing interpretations of DDSs: development by defrosting alone, and by defrosting and melting enhanced by the activity of Martian Surface Organisms (MSOs). MSOs are hypothetical Martian photosynthetic surface organisms thought to absorb sunlight. As a result they warm up by late winter and melt the ice around them, whereby their growth and reproduction become possible. The ice cover above the liquid water lens harbouring the MSOs provides excellent heat and UV insulation, preventsfast evaporation, and sustains basic living conditions until the ice cover exists. When the frost cover disappears MSOs go to a dormant, desiccated state. We propose further studies to be carried out by orbiters and landers travelling to Mars and by analysis of partial analogues on earth.     

云南高黎贡山地区主要药用蕨类植物

通过对高黎贡山地区的民间访谈和集市药摊调查 ,从高黎贡山地区已纪录的 5 38种蕨类植物中总结、整理出主要的药用蕨类植物 85种 ,分属 2 7科 ,4 4属。本文主要对其中对 17种常见药用蕨类植物的药用功效进行介绍     

现存被子植物原始类群及其植物地理学研究

在吸取各学派对被子植物原始类群界定的基础上,根据八纲系统,提出被子植物原始类群有60科的新见解,并以分子系统学提出的狭义的基部类群32科为对比,进行了植物地理学研究。以科为性状,以Takhtajan 划分的世界植物区系的“区”为OTU,UPGMA分析显示：(1)东亚区确是一个十分特殊的区,它既与北美东、西部(北美大西洋区、马德雷区)有密切关系,但更接近印度支那区;(2)环太平洋的4个地区集中了较多的原始被子植物的科,它们是东亚地区,北美东部和西部地区,部分热带亚洲、澳大利亚东部和西南太平洋岛屿地区,中、南美热带地区。这种分布格局显然和被子植物起源地与扩散以及太平洋的形成历史有关。     

Recognition of the main geobotanical features along the Bragança mangrove coast (Brazilian Amazon Region) from Landsat TM and RADARSAT-1 data

Orbital remote sensing data were assessedfor mapping of the main geomorphologicaland vegetation units of the Bragançapeninsula (North Brazil), which belongs toa vast though sparsely mapped mangrovecoast. Wide wetland environmentscharacterize the region with extremevariations in extension, temporalevolution, and spatial complexity. Thiswork was based on different digitalprocessing techniques separately applied toLandsat TM and RADARSAT-1 images. Inaddition, both data were merged on apixel-to-pixel basis using algorithms,which rendered an enhancement of thecoastal landforms and a betterdiscrimination of wetlands and landformtypes. The interpretation of the integratedproduct, aided by field validation, made itpossible to significantly extend existingmapping. Nineteen geobotanical units wereidentified: estuarine channels, submergedsand banks, sandflats, old estuarinesandbanks, mudflats, ebb-tidal deltas,barrier-beach ridges, coastal dunes,chenier sand ridges, young intertidalmangroves, intertidal and supratidalmangroves, outer and inner marshes, fluvialflood plains, coastal plateau, degraded andregenerated mangroves, and an artificiallagoon. The digital integration of Fine RADARSAT-1 and Landsat TM data sensitivelyhighlighted geobotanical coastal features,providing a useful tool for a synopticanalysis of their natural and man-drivenchanges.     

内蒙古自治区上侏罗统最原始的蠼螋昆虫化石(昆虫纲:革翅目:始螋亚目)

我国上侏罗统牛津阶-基末利阶（163-150Ma)保存有完好的最原始的蠼螋昆虫化石,首次描述,分析和讨论了原始蠼螋后翅脉序特征,认为与现代生存的蠼螋后翅基本相同。因此,提出了与西方某些蠼螋昆虫分类学者不同的意见,认为始螋亚目（Aechidermaptera)应归入于革翅目（Dermaptera)之中,且视其为一个最原始的类群较为合理,内蒙古自治区这个原始类群的下列重要特征皆为首次发现;胸骨具有特殊的形态结构;革翅锁具（Tegmina locking device)和刺脊突（spiny crest)发育;前,中,后足跗节皆为5节;后足基节显著伸长;颈部被划分为前,后两个颈片;革翅后缘收缩变尖,上述5项被视为厚原始蠼螋特有的祖征,下列特征应为早期蠼螋共有的原始性状;虫体扁平,通常具毛;腹部侧缘彼此近平行;触角显长,丝状,多节（通常多于11节）;两只单眼发育;上颚具齿;中胸小盾片显大;革翅较长,通常具有明显的翅脉;股节具隆脊;爪和爪垫通常发育;腹部各节背板与腹板不重叠（两者位置非简单的上,下关系）;尾须柔软,多节,雌性产卵器鞘显著外伸,本文建立了始螋亚目1新科Sinopalaeo-dermatidae和2新属2新种Sinopalaeodermata neimonggolensis gen.et sp.nov,Jurassimedeola orientalis gen,et sp.nov。同时,对蠼螋昆虫的起源和演化重新进行了讨论,做出了与西方某些蠼螋昆虫研究者结论不同的推断。