云南武定中泥盆世晚期植物与腹足动物共生标本的发现及其古生态意义

中泥盆世晚期陆生植物的演化已经达到相当高的水平,我国以云南中泥盆世晚期植物群为代表,称为Lepidodendropsis arborecense-Minarodendron cathaysiense-Eocladoxylou minutum (LME)组合。当前在云南武定中泥盆世晚期地层(西冲组上部)中发现的植物主要有Lepidodendropsis arborescense,Eocladoxylon minutu,Rhipidophyton acanthum等,其中,在R.acanthum的茎干基部密集共生有腹足动物Valvata sp.。根据植物表面无动物咬食痕迹,以及腹足动物生态特性和演化分析,当前陆生植物与水生动物共生的原因是植物茎干飘落水体后,为水生的腹足动物提供了新的栖息场所,并随水流、风浪载运至异地埋藏。这种水生腹足动物寄栖于水中物体的生活方式很普遍,是腹足动物迁徙、扩散的一种重要途径。     

THE ULTRASTRUCTURE AND CYTOCHEMISTRY OF RESTING CELL FORMATION IN AMPHORA COFFAEFORMIS (BACILLARIOPHYCEAE)1

The ultrastructure of logarithmic-growing cells and of resting cells in laboratory cultures of Amphora coffaeformis (Ag.) Kütz. isolated from deep ocean water was examined using electron and light microscopy. The acid Phosphatase activity, chlorophyll a and lipid content were assessed at weekly intervals of resting cell formation during cold-dark treatment, simulating deep ocean water. Approximately 4 wk are required to complete resting cell formation. During the first week, the cytoplasm undergoes extensive transformation and lysosomal activity is observed. Large vacules decrease in size and many small ones develop, the mitochondria become fewer and one or more massive mitochondria appear possibly by fusion of smaller ones; the cytoplasm becomes densely granular. During the second and third week, the cytoplasm continues to contract, lipid bodies begin to develop and the plastid becomes densely stained. At the fourth week, the mature resting cell is formed containing one or more massive mitochondria, a well-formed plastid, and granular cytoplasm containing occasional lipid droplets. There is no change in frustule morphology and the cytoplasm does not produce a protective layer. The variation in chemical constituents correlates with microscopic structure of the cells. The fine structure of cells during growth resumption when exposed to light at 25 c is presented. Previous reports of viable, chlorophyll-containing cells at great depths in the ocean may be explained by the results reported in this paper.     

云南西冲组的一种细小植物—兼论华南中泥盆世晚期植物组合

研究我国云南中泥盆世晚期西冲组的一种细小植物Psilophyton striatum sp.nov.,它具有二歧分叉光滑轴和生殖枝,生殖枝由三次等二歧分叉枝系和族生孢子囊组成,枝系末端对生两对直立孢子囊,根据对已有材料的分析,宜将华南中泥盆世晚期植物组合改名为Lepidodendropsis arborescense-Minarodendron cathaysiense Eocladoxylon minutum(LME)组合,它以石松类植物为主,共生有“真蕨植物”和三枝蕨类,分为小形树状植物和地面植物两个生态系统,同时,与世界上同期植物群进行了对比。     

泥盆纪锥石类Changshaconus Zhu,1985和Reticulaconularia Babcock et Feldmann,1986两属的解剖学和系统学

重新描述了湖南中泥盆世的锥石Ｃｈａｎｇｓｈａｃｏｎｕｓ ｃａｒｉｎａｔａ Ｚｈｕ,１９８５。通过比较,笔者认为Ｃｈａｎｇｓｈａｃｏｎｕｓ与产自南非泥盆系和南、北美洲下泥盆统中的Ｒｅｔｉｃｕｌａｃｏｎｕｌａｒｉａ Ｂａｂｃｏｃｋ ｅｔ Ｆｅｌｄｍａｎｎ,１９８６非常相似。Ｃｈａｎｇｓｈａｃｏｎｕｓ和Ｒｅｔｉｃｕｌａｃｏｎｕｌａｒｉａ两属由于锥管表面横肋间具有纵向脊状构造,与横肋构造一起构成了网状的表     

贵州独山中泥盆世动藻迹生态习性探讨

贵州独山中泥盆统产有丰富的遗迹化石Zoopkycos,现从其产出的特征和古生态等方面对其生活习性进行探讨。认为分布于静水、贫氧、有机质丰富环境的Zoopkycos为螺旋向上的内生觅食构造;边缘管一端通过中央通道与海水相通,呈“J”形;蹼状构造系造迹生物觅食区域的扩大、边缘管增大而形成;同一个体的Zoopkycos可以分出许多的与蹼状构造变化规律相近的、具同一边缘管的觅食序列(food-system),每一觅食序列的边缘管具有一端向上与中央通道相通,另一端向下与相邻觅食序列的边缘管相联;螺旋的疏密、大小与相对沉积速度有关。产于独山地区中泥盆统的Zoopkycos的造迹生物可能是星虫类(sipunculids)。     

摩尔达瓦新石器时代环境变化与农业发展的孢粉学证据

新石器居民点Sakarovka(Krish文化）位于摩尔达瓦西北部,它代表了欧洲第一个农业文明,这一文化在新石器时代早期广泛分布于前南斯拉夫和现匈牙利,罗马尼亚及摩尔达瓦地区,这些地区Krish文化层的14C同位素年代为6650＋／－50年,或者公元前5600－1480年,现有的孢粉资料显示,当时的森林－草原植被生长在比现代更好的气候环境下,谷物（Triticum,Avena,Hordeum)花粉及伴生的杂草花粉可以证明当时的农业活动,在Krish文化的末期,森林面积减少和喜旱的禾草类增加是由于气候干旱化,木材开发以及开辟新的可耕地引起的。     

从底栖生物化石再释贵州独山泥盆系龙洞水段的时代

贵州独山的猴儿山组龙洞水段是一套浅海相碳酸盐沉积,盛产底栖牛物化石.通过对该段地层中所含四射珊瑚、床板珊瑚和腕足类等化石属种的详尽分析,再次证实龙洞水段的地质时代仍应属中泥盆世早期(Eifelian).而不是像某些根据痕迹化石或层序地层学的研究那样将它置于下泥盆统.     

ULTRASTRUCTURE OF CHAETOCEROS MUELLERI (BACILLARIOPHYCEAE): AUXOSPORE,RESTING SPORE AND VEGETATIVE CELL MORPHOLOGY1

The structure of the frustule of auxospores, resting spores and vegetative cells of Chaetoceros muelleri Lemm. are described with LM and SEM. Vegetative frustules are relatively small and lightly silicified, are not united into filaments, and appear unornamented under LM and SEM. The setae are circular to subcircular in transverse section with spines and puncta arranged in a spiral pattern. The resting spore and auxospore frustules are more silicified than the vegetative frustules and appear unornamented under LM and SEM. The auxospores of C. muelleri were previously unknown.     

广西早泥盆世节甲鱼类及胴甲鱼类化石及华南早泥盆世脊椎动物生物地层对比

描述了早泥盆世的3个属种,其中节甲鱼类Yujiangolepisliujingensisgen．etsp.nov.采自广西六景,Buchanosteussp．及胴甲鱼类？Chuchinolepissp.采自广西玉林。该3件标本均产自海相地层中,与海相无脊椎动物化石共生。还讨论了华南区几个主要产脊椎动物化石（包括脊椎动物微体化石）剖面的生物地层对比。     

PIGMENT AND CYTOLOGICAL EVIDENCE FOR RECLASSIFICATION OF NANNOCHLORIS OCULATA AND MONALIANTUS SALINA IN THE EUSTIGMATOPHYCEAE1

Nannochloris oculata Droop and Monallantus salina Bourrelly produce similar chloroplast pigments and show alike ultrastructural features separating them from the Chlorophyceae and Xanthophyceae, respectively, and linking them to the Eustigmatophyceae. It is proposed that N. oculata should be removed from the chlorophyceaen genus Nannochloris and transferred to a new taxon of coccoid eustigmatophytes containing the closely related M. salina: nomenclatural revisions are required for both strains.     

EVIDENCE FOR INHIBITORS OF SPORANGIUM FORMATION IN LAMINARIA DIGITATA (PHAEOPHYCEAE) DURING THE SEASON OF RAPID GROWTH

The pathway from the intercalary frond meristem to distal frond portions was blocked in experimental sporophytes of Laminaria digitata (Huds.) Lamour. in January by cutting 2 or 3 holes (15–25 mm diameter) 5 cm from the base of the frond. This procedure resulted in the formation of sori adjacent to the distal edge of the holes within 5–10 weeks. Frond portions that were cut at least 20 cm away from the stipe–frond transition readily formed sori within 5–7 weeks after isolation from the rest of the thallus. These findings suggest that the basal actively dividing and expanding part of the laminarian frond is the source of inhibitors of sporangium formation that move in a distal direction and keep the young frond free of sori during the season of rapid growth (i.e. during the first part of the year). The natural occurrence of sori during the season of slow growth (i.e. the second part of the year in the Northern Hemisphere) may be due to reduced synthesis and export of inhibitors of sporangium formation from the more or less resting basal meristem.     

华南浅海相泥盆系吉维特阶和弗拉阶四射珊瑚组合特征

中泥盆世吉维特晚期(更精确的说是在中吉维特期末)发生的生物更替事件使大量的头贝、全部的泡沫珊瑚亚目以及大多数的绳珊瑚科和内板珊瑚科惨遭灭绝。晚泥盆世弗拉期出现了许多新生分子,诸如Micto-phyllum,Wapitiphyllum,Pseudozaphrentis,Peneckiella等。根据珊瑚的不同组合特征可以鉴别出它们的地质时代。华南自上而下可划分出4个四射珊瑚组合,分别为上泥盆统弗拉阶(Frasnian):4)Disphyllum-Wapitiphyl-lum组合(牙形类gigas或rhenana带和hassi-jamieae带),3)Mictophyllum-Pseudozaphrentis组合(牙形类asymmetricus带);中泥盆统吉维特阶(Givetian):2)Endophyllum-Sunophyllum组合(牙形类varcus带的中部和下部之上段),1)Stringophyllum-Paramixogonaria组合(牙形类hemiansatus带-varcus带最下部)。     

PATTERNS OF EVOLUTION AND EXTINCTION IN THE LAST HARPETID TRILOBITES DURING THE LATE DEVONIAN (FRASNIAN)

Abstract: Late Devonian (Frasnian) harpetid trilobites have hitherto only been described from the western side of the Protethys Ocean, in what is now Europe and North Africa, as well as from Gondwana‐derived northwestern Kazakhstan (Mugodjar). However, late Frasnian strata in the Canning Basin, Western Australia, that were deposited on the eastern side of this ocean, contain a rich harpetid fauna. Described herein are two new harpetids: Eskoharpes gen. nov. and Globoharpes gen. nov., within which are placed six species: E. palanasus sp. nov., E. wandjina sp. nov., E. boltoni sp. nov., E. guthae sp. nov., G. teicherti sp. nov. and G. friendi sp. nov. The ontogenetic development of E. palanasus, E. wandjina and G. teicherti are described, including the first unequivocal harpetid protaspis. Globoharpes exhibits evidence of sexual dimorphism in the development of a pronounced preglabellar boss in some specimens. This structure is thought to have functioned as a brood pouch. Such structures have previously only been described in Cambrian and Ordovician trilobites, and never before in harpetids. It is suggested that the characteristic harpetid fringe functioned as a secondary respiratory structure. The Eskoharpes lineage shows evolutionary trends that mirror changes seen in ontogenetic development of the youngest species, suggesting the operation of peramorphic processes. This is the first record of heterochrony in harpetids and the first documented example of peramorphosis in Devonian trilobites. These harpetids demonstrate a stepped pattern of extinction during the late Frasnian, probably related to the effects of the two Kellwasser biocrises that have been well documented in European Frasnian sections. Highly vaulted species of Eskoharpes and the strongly vaulted Globoharpes became extinct at the Lower Kellwasser Event. The flatter species of Eskoharpes became extinct at the base of the Upper Kellwasser Event shortly prior to the Frasnian/Famennian boundary. The extinction of these harpetids, along with contemporaneous forms from Europe, which are also discussed herein, marks the end of the trilobite order Harpetida worldwide.     

AND IF ENGLER WAS NOT COMPLETELY WRONG? EVIDENCE FOR MULTIPLE EVOLUTIONARY ORIGINS IN THE MOSS FLORA OF MACARONESIA

The Macaronesian endemic flora has traditionally been interpreted as a relict of a subtropical element that spanned across Europe in the Tertiary. This hypothesis is revisited in the moss subfamily Helicodontioideae based on molecular divergence estimates derived from two independent calibration techniques either employing fossil evidence or using an Monte Carlo Markov Chain (MCMC) to sample absolute rates of nucleotide substitution from a prior distribution encompassing a wide range of rates documented across land plants. Both analyses suggest that the monotypic Madeiran endemic genus Hedenasiastrum diverged of other Helicodontioideae about 40 million years, that is, well before Macaronesian archipelagos actually emerged, in agreement with the relict hypothesis. Hedenasiastrum is characterized by a plesiomorphic morphology, which is suggestive of a complete morphological stasis over 40 million years. Macaronesian endemic Rhynchostegiella species, whose polyphyletic origin involves multiple colonization events, evolved much more recently, and yet accumulated many more morphological novelties than H. percurrens. The Macaronesian moss flora thus appears as a complex mix of ancient relicts and more recently dispersed, fast‐evolving taxa.     

三峡库区稀有濒危植物异地保护群落设计的初步研究

提出了建造群落舁地保护三峡库区稀有濒危植物的方法。从地点选择、面积确定、物种组成和群落结构等方面探讨了异地保护群落设计的原理和方法。根据对三峡库区及其附近的残存稀有濒危植物群落的调查,选择九宫山自然保护区的一个独特生境,设计了一个面积约３０００ｍ＾２,优势种为珙桐（Ｄａｖｉｄｉａ ｉｎｖｏｌｕｃｒａｔａ）、金线槭（Ｄｉｐｔｅｒｏｎｉａ ｓｉｎｅｎｓｉｓ）、水青树（Ｔｅｔｒａｃｅｎｔｒｏｎ ｓｉｎｒ     

华南中泥盆世艾菲尔期浅海相四射珊瑚的组合特征和古生物地理区系

虽然在华南中泥盆世艾菲尔期(Eifelian)较深水或斜坡相地层中产有许多国际标准的牙形类带化石,但在广阔的浅海相地层中却很难寻觅到其踪影。华南浅海相沉积地区是否缺失艾菲尔阶?在野外众多剖面的实地考察中表明,从下泥盆统埃姆斯阶到中泥盆统吉维特阶都是连续沉积,中间并没有发现地层的缺失或间断现象。浅海相的艾菲尔阶与其上覆的吉维特阶和下伏的埃姆斯阶都是连续沉积,说明可能是由于海水太浅,不太适合那些国际标准分子的生存而已。艾菲尔期中期末发生一次生物灭绝事件(Mid-Eifelian event),favositids,heliolitids和许多古老类型的珊瑚在地球上灭绝。华南艾菲尔期四射珊瑚可以划分成下、上两个完全不同的组合:1)Utara-tuiasinen sis-Sociop hyllum minor组合(牙形类partitus带—costatus带);2)Columnaria spinosa-Dendrostella praerhenana组合(牙形类australis带—kocklianus带)。     

ULTRASTRUCTURE OF CELL DIVISION AND REPRODUCTIVE DIFFERENTIATION OF MALE PLANTS IN THE FLORIDEOPHYCEAE (RHODOPHYTA): CELL DIVISION IN POLYSIPHONIA1

Cell division in the marine red algae Polysiphonia harveyi Bailey and P. denudata (Dillwyn) Kutzing was studied with the electron microscope. Cells comprising the compact spermatangial branches of male plants were used exclusively because of their small size, large numbers and the ease with which the division planes can be predetermined. Some features characterizing mitosis in Polysiphonia confirm earlier electron microscope observations in Membranoptera, the only other florideophycean algae in which mitosis has been studied in detail. Common to both genera are a closed, fenestrated spindle, perinuclear endoplasmic reticulum, a typical metaphase plate arrangement of chromosomes, conspicuous, layered kinetochores, chromosomal and non-chromosomal microtubules, and nucleus associated organelles (NAOs) known as polar rings (PRs) located singly in large ribosome-free zones of exclusion at division poles in late prophase. However, other features, unreported in Membranoptera, were observed consistently in Polysiphonia. These include the presence of PR pairs in interphase-early prophase cells, the attachment of PRs to the nuclear envelope during all mitotic stages, the migration of a single PR to establish the division axis, a prominent, nuclear envelope protrusion (NEP) at both division poles at late prophase, the prometaphase splitting of PRs into proximal and distal portions, and the reformation of post-mitotic nuclei by the separation of an elongated interzonal nuclear midpiece at telophase. During cytokinesis, cleavage furrows impinge upon a central vacuolar region located between the two nuclei and eventually pit connections are formed in a manner basically similar to that reported for other red algae. Diagrammatic sequences of proposed PR behavior during mitosis are presented which can account for events known to occur during cell division in Polysiphonia. Mitosis is compared with that reported in several other lower plants and it is suggested that features of cell division are useful criteria to aid in the assessment of phylogenetic relationships of red algae.     

瓶囊碘泡虫成熟孢子的显微及亚显微结构研究

应用光镜、透射电镜和扫描电镜观察,瓶囊碘泡虫Myxobolus ampullicapsulatus Zhao et al.,2008成熟孢子由孢壳、极囊和孢质3部分组成.其孢子壳面观呈梨形,缝面观呈凸透镜形,囊间突明显;2片孢壳厚而均匀且表面凹凸不平.极囊瓶形,位于孢子前端,约占整个孢子长度的2/3;极囊壁由"暗-明"2部分组成;极丝呈双"S"形缠绕并沿极囊纵轴逆时针向上螺旋8～11圈.孢质均匀而稠密,近球形的2个胚核大小不一;孢质中除了可观察到丰富的线粒体、粗面内质网、核糖体、高尔基体、嗜碘泡等细胞器及脂滴等泡状结构外,还可于孢质中观察到有一些数目不等的球状电子致密物质,其中2个分布于极囊周围.     

THE KINETICS OF THE PHOTOACCLIMATION RESPONSE OF NANNOCHLOROPSIS SP. (EUSTIGMATOPHYCEAE): A STUDY OF CHANGES IN ULTRASTRUCTURE AND PSU DENSITY

In this study we report the kinetics of photoacclimation of the unicellular alga Nannochloropsis sp. grown under high light (HL), and subsequently transferred to low light (LL). We examined the changes in ultrastructural features, pigmentation, and photosynthetic parameters over short intervals until the LL steady state was reached. The ultrastructural changes were followed by quantitative morphometric measurements of transmission electron micrographs. We found that the increase in the relative volume of the chloroplast during acclimation to LL (twofold) was accompanied by an increase in number of stacks (twofold) and in the surface area of thylakoids per cell (2.5-fold). The increase in photosynthetic unit (PSU) density was about 2.15-fold. Maximal density was about 84 PSU·μm⁻² in LL cells, and minimal density was 39 PSU·μm⁻² in HL cells. The HL/LL ratio of the in vivo optical absorption cross-section of PSU (σ_PSU) was 2.8, whereas in the in vivo optical absorption cross-section of the cell (σ_cell), the trend of change was in the opposite direction: 1.7-fold higher in LL-acclimated cells than in HL-acclimated cells. We propose a partial sequence of the photoacclimation processes based on our data and the derived rate constants.