Lichen-like symbiosis 600 million years ago

The fossil record of fungi and lichens is scarce. Here we report the discovery of lichen-like fossils, involving filamentous hyphae closely associated with coccoidal cyanobacteria or algae, preserved in marine phosphorite of the Doushantuo Formation (between 551 and 635 million years old) at Weng'an, South China. These fossils indicate that fungi developed symbiotic partnerships with photoautotrophs before the evolution of vascular plants.     

Arctic terrestrial biota: paleomagnetic evidence of age disparity with mid-northern latitudes during the late cretaceous and early tertiary

Magnetostratigraphic correlation of the Eureka Sound Formation in the Canadian high Arctic reveals profound difference between the time of appearance of fossil land plants and vertebrates in the Arctic and in mid-northern latitudes. Latest Cretaceous plant fossils in the Arctic predate mid-latitude occurrences by as much as 18 million years, while typical Eocene vertebrate fossils appear some 2 to 4 million years early.     

Molecular evidence for the early colonization of land by fungi and plants

The colonization of land by eukaryotes probably was facilitated by a partnership (symbiosis) between a photosynthesizing organism (phototroph) and a fungus. However, the time when colonization occurred remains speculative. The first fossil land plants and fungi appeared 480 to 460 million years ago (Ma), whereas molecular clock estimates suggest an earlier colonization of land, about 600 Ma. Our protein sequence analyses indicate that green algae and major lineages of fungi were present 1000 Ma and that land plants appeared by 700 Ma, possibly affecting Earth's atmosphere, climate, and evolution of animals in the Precambrian.     

Evolutionary history of the symbiosis between fungus-growing ants and their fungi

The evolutionary history of the symbiosis between fungus-growing ants (Attini) and their fungi was elucidated by comparing phylogenies of both symbionts. The fungal phylogeny based on cladistic analyses of nuclear 28S ribosomal DNA indicates that, in contrast with the monophyly of the ants, the attine fungi are polyphyletic. Most cultivated fungi belong to the basidiomycete family Lepiotaceae; however, one ant genus, Apterostigma, has acquired a distantly related basidiomycete lineage. Phylogenetic patterns suggest that some primitive attines may have repeatedly acquired lepiotaceous symbionts. In contrast, the most derived attines have clonally propagated the same fungal lineage for at least 23 million years.     

Recent synchronous radiation of a living fossil

Modern survivors of previously more diverse lineages are regarded as living fossils, particularly when characterized by morphological stasis. Cycads are often cited as a classic example, reaching their greatest diversity during the Jurassic-Cretaceous (199.6 to 65.5 million years ago) then dwindling to their present diversity of ~300 species as flowering plants rose to dominance. Using fossil-calibrated molecular phylogenies, we show that cycads underwent a near synchronous global rediversification beginning in the late Miocene, followed by a slowdown toward the Recent. Although the cycad lineage is ancient, our timetrees indicate that living cycad species are not much older than ~12 million years. These data reject the hypothesized role of dinosaurs in generating extant diversity and the designation of today's cycad species as living fossils.     

Fossil land mammal from antarctica

A fossil land mammal, apparently the first found in Antarctica, belongs to the extinct marsupial family Polydolopidae. The fossils were recovered from rocks about 40 million years old on Seymour Island, in the northern Antarctic Peninsula. The newly discovered marsupials support theories that predicted their former presence in Antarctica and strengthen proposals that Australian marsupials perhaps originated from South American species that dispersed across Antarctica when Australia still was attached to it, prior to 56 million years ago.     

Paleontology. Biggest extinction hit land and sea

Two hundred and fifty million years ago, at the end of the Permian period and the opening of the Triassic, 85% of the species in the sea vanished in a geologic moment of less than half a million years. Now from South Africa comes evidence that the Permian-Triassic extinction of land plants was equally brutal and swift. In a paper on page 1740 of this issue of Science, researchers report that rocks that started as sediments laid down in South Africa's Karoo Basin 250 million years ago tell of an abrupt switch in style of sedimentation, as if the land had been permanently stripped of the rooted plants that held it in place. But in the absence of any trace of an impact, researchers are groping for an equally far-reaching explanation.     

采煤塌陷复垦区先锋植物根际微生物数量的变化

采用以空间代替时间的方法,研究了采煤塌陷区复垦后土壤自然演替状况下先锋植物根际微生物数量和组成的变化,探讨不同先锋植物根际微生物变化的特征和规律。结果表明,不同先锋植物其根际微生物的数量不同,其中,复垦1年后的土壤,狗尾草[Setaria viridis(L.)Beauv.]的根际细菌、真菌和放线菌数量及微生物总量均大于刺儿菜[Cirsium setosum Willd.ex MB.]的根际微生物数量,复垦3年后则相反;两种先锋植物根际微生物的数量均随着复垦年限的延长而显著增加,其中,细菌和放线菌数量增加的较快,因此,细菌所占微生物总量的比例随着复垦年限延长而增加,而真菌的比例降低。复垦后土壤上的先锋植物根际效应十分明显,从微生物类群来看,根际效应是真菌放线菌细菌,从植物类别来看,复垦1年后的土壤上,先锋植物狗尾草的根际效应大于刺儿菜,但复垦3年后则相反,说明随着物种和时间的变化,根际效应也发生变化。     

Miocene characid fishes from Colombia: evolutionary stasis and extirpation

Fossil fishes from the Miocene La Venta fauna of the Magdalena River Valley, Colombia, are identified as Colossoma macropomum (Characidae), a living species from the Orinoco and Amazon basins. The fossils document a long and conservative history for a species that is highly specialized for feeding on streamside plants. The phylogenetically advanced position of Colossoma in the subfamily Serrasalminae implies that six related genera and other higher characid taxa originated well before 15 million years ago. This discovery also corroborates neontological evidence for a vicariance event that contributed species from Miocene Orinoco-Amazon faunas to the original Magdalena region fauna. The fossils suggest a formerly diverse Magdalena fauna that has suffered local extinction, perhaps associated with late Cenozoic tectonism. This new evidence may help explain the depauperate nature of the modern Magdalena River.     

长期施用氮肥和磷肥对东北黑土丛枝菌根真菌群落组成的影响

【目的】丛枝菌根(Arbuscular mycorrhizae,AM)真菌在促进作物养分吸收、提高作物抗病和抗逆性等方面具有重要意义,探讨长期施用化学氮肥和磷肥对东北黑土AM真菌的影响及其主效环境因子,为进一步揭示AM真菌对化肥的响应机制,指导农田施肥以及利用AM真菌提高土壤养分有效性提供依据。【方法】以长期定位试验为平台,选取5种不同处理:不施肥(CK),单施常量氮肥(N_1),混施常量氮肥和磷肥(N_1P_1),单施2倍常量氮肥(N_2),混施2倍常量氮肥和磷肥(N_2P_2)。采用Illumina Miseq高通量测序技术研究连续施用37年氮肥和磷肥的AM真菌群落组成差异,并对AM真菌群落组成与环境因子进行相关性分析。【结果】随着氮、磷施用量的增加,黑土p H和速效钾含量显著降低,而全氮、硝态氮、铵态氮和有机质含量显著提高。单施氮肥(N_1和N_2)对黑土中AM真菌多样性影响不显著(P0.05);然而氮、磷混施(N_1P_1和N_2P_2)显著降低黑土中AM真菌多样性(P0.05)。土壤中AM真菌以Glomeraceae科为主,占AM真菌45.5%。在属水平上,施肥降低Funneliformis和Septoglomus丰度,而提高Paraglomus丰度;在N_1和N_2基础上施磷显著提高Glomus和Funneliformis丰度,而降低Gigaspora和Paraglomus的丰度。非度量多维度分析表明,长期施用氮、磷肥改变了土壤中AM真菌群落组成。不施肥处理、单施氮肥处理和氮、磷混施处理AM真菌群落差异显著,且磷肥影响较为显著。冗余分析表明,土壤p H,有效磷含量是影响黑土中AM真菌群落组成的主效环境因子(P0.05)。【结论】长期施用氮肥以及氮、磷肥混施改变了黑土中AM真菌群落组成,单施氮肥对黑土中AM真菌多样性影响不大,而氮、磷肥混施降低其多样性,施肥导致的土壤p H和有效磷含量变化是主要因素。     

Archaefructaceae, a new basal angiosperm family

Archaefructaceae is proposed as a new basal angiosperm family of herbaceous aquatic plants. This family consists of the fossils Archaefructus liaoningensis and A. sinensis sp. nov. Complete plants from roots to fertile shoots are known. Their age is a minimum of 124.6 million years from the Yixian Formation, Liaoning, China. They are a sister clade to all angiosperms when their characters are included in a combined three-gene molecular and morphological analysis. Their reproductive axes lack petals and sepals and bear stamens in pairs below conduplicate carpels.     

Hand of Paranthropus robustus from Member 1, Swartkrans: fossil evidence for tool behavior

New hand fossils from Swartkrans (dated at about 1.8 million years ago) indicate that the hand of Paranthropus robustus was adapted for precision grasping. Functional morphology suggests that Paranthropus could have used tools, possibly for plant procurement and processing. The new fossils further suggest that absence of tool behavior was not responsible for the demise of the "robust" lineage. Conversely, these new fossils indicate that the acquisition of tool behavior does not account for the emergence and success of early Homo.     

Terrestrial soft-bodied protists and other microorganisms in triassic amber

Protozoa, cyanobacteria, sheathed algae, sheathed fungi, germinating pollen or spores, and fungal spores have been found in amber 220 to 230 million years old. Many of these microorganisms can be assigned to present-day groups. This discovery of terrestrial, soft-bodied protists that can be referred to modern groups indicates that morphological evolution is very gradual in many protists and that both structural and probably functional stasis extend back at least to the Upper Triassic period.     

U-Pb ages from the neoproterozoic Doushantuo Formation, China

U-Pb zircon dates from volcanic ash beds within the Doushantuo Formation (China) indicate that its deposition occurred between 635 and 551 million years ago. The base records termination of the global-scale Marinoan glaciation and is coeval with similar dated rocks from Namibia, indicating synchronous deglaciation. Carbon isotopic and sequence-stratigraphic data imply that the spectacular animal fossils of the Doushantuo Formation are for the most part younger than 580 million years old. The uppermost Doushantuo Formation contains a pronounced negative carbonate carbon isotopic excursion, which we interpret as a global event at circa 551 million years ago.     

红果型沙地云杉内生真菌多样性

了解沙地云杉植物内生真菌生态多样性,为沙地云杉内生真菌的种属鉴别和资源的开发利用提供科学的依据,并为下一步深入研究内生真菌代谢产物提供理论基础。对内蒙古自治区克什克腾旗白音敖包自然保护区的沙地云杉进行调查,采用组织分离法对沙地云杉的不同组织部位进行内生真菌分离,以形态学和分子生物学相结合的方法进行鉴定,选取其中60株进行扩增、测序和系统发育分析。从系统发育树可见,菌株聚为2个大分支,分别为子囊菌亚门和半知菌亚门,10个小分支对应7个科分属于10个属12种,其中链格孢属（Alternaria）与青霉属（Penicillium）为优势菌属,红果型沙地云杉内生真菌菌种资源较丰富。     

Australopithecus sediba at 1.977 Ma and implications for the origins of the genus Homo

Newly exposed cave sediments at the Malapa site include a flowstone layer capping the sedimentary unit containing the Australopithecus sediba fossils. Uranium-lead dating of the flowstone, combined with paleomagnetic and stratigraphic analysis of the flowstone and underlying sediments, provides a tightly constrained date of 1.977 ± 0.002 million years ago (Ma) for these fossils. This refined dating suggests that Au. sediba from Malapa predates the earliest uncontested evidence for Homo in Africa.     

黄河三角洲盐碱地土壤真菌多样性及其与土壤理化性质的关系

采用454高通量测序(454 high throughput sequencing)分析方法,研究不同覆被(光板地和柽柳群落以及白茅群落)类型下土壤真菌组成、多样性及与理化性质的关系。该研究共获得5门174属真菌,不同土样中真菌种类和多样性有所不同,其中,白茅群落真菌的种类较多,尤其是HZ3A(白茅0~20 cm)中真菌属数量最多,其真菌属分别是HZ1A(光板地0~20 cm)、HZ1B(光板地20~40 cm)、HZ2A(柽柳0~20 cm)、HZ2B(柽柳20~40 cm)、HZ3B(白茅20~40 cm)的2.23、1.74、1.24、2.18和1.38倍。此外,白茅群落真菌多样性高于柽柳群落和光板地。碱解氮对土壤真菌多样性和分布的影响最大,其与Knufia、旋孢腔菌属(Cochliobolus)、毛霉属(Mucor)、马拉色氏霉菌属(Malassezia)的相对丰度呈负相关,与其余真菌属的相对丰度呈正相关。     

大豆胞囊线虫病的生防因子研究进展

综述了大豆胞囊线虫的各类生防因子,如食线虫真菌、食线虫细菌、杀线虫植物、捕食性线虫和捕食性土壤动物等,其中研究较深入的是食线虫真菌和细菌,食线虫真菌可归纳为5种类型,即捕食性真菌、专性内寄生菌物、机会真菌、产毒真菌和菌根菌;另外,还对其他生防因子的最新研究结果进行了归类综述,并对大豆胞囊线虫的生物防治进行了展望。     

土壤类型和树种对根际土丛枝菌根真菌群落及其根系侵染率的影响

为合理利用丛枝菌根(Arbuscular Mycorrhiza,AM)真菌促进喀斯特退化土地植被恢复,采用形态学方法研究了土壤类型(石灰土和黄壤)和宿主植物种类(紫弹树(Celtis biondii Pamp)、红锥(Castanopsis hystrix)和单性木兰(Kmeria septentrionalis Dandy))对AM真菌群落结构的影响。研究共分离鉴定了2属14种AM真菌,其中幼套球囊霉(Glomus etunicatum)是石灰土和黄壤共有的优势种,石灰土特有的AM真菌包括地球囊霉(G.geosporum)、白色球囊霉(G.albidum)、双型球囊霉(G.ambisporum)、象牙白球囊霉(G.eburneum)和细凹无梗囊霉(G.scrobiculata),而波状无梗囊霉(A.undulata)是黄壤特有的AM真菌。土壤类型对AM真菌孢子密度,Shannon多样性指数以及侵染率具有显著影响;宿主植物种类与AM真菌Shannon多样性指数呈显著相关。石灰土紫弹树和单性木兰根际土AM真菌孢子丰度显著高于黄壤相同植物的,而红锥无显著差异;石灰土紫弹树和红锥的AM真菌物种丰富度及Shannon多样性指数均高于黄壤同种植物的。土壤类型对AM真菌孢子密度、物种丰富度、Shannon多样性指数和侵染率均有显著影响,对均匀度指数也有显著影响;植物种类对Shannon多样性指数有显著影响,且AM真菌物种丰富度、Shannon多样性指数和侵染率受土壤类型与植物种类交互作用的显著影响;土壤p H和全钾含量对AM真菌群落影响显著。因此,利用AM真菌促进喀斯特植物定植生长与植被恢复过程中,应该考虑喀斯特土壤AM真菌具有区域特异性和物种偏好性。     

Discoidal impressions and trace-like fossils more than 1200 million years old

The Stirling Range Formation of southwestern Australia contains discoidal impressions and trace-like fossils in tidal sandstones. The various disks have previously been linked to the Ediacaran biota, younger than 600 million years old. From this unit, we report U-Th-Pb geochronology of detrital zircon and monazite, as well as low-grade metamorphic monazite, constraining the depositional age to between 2016 +/- 6 and 1215 +/- 20 million years old. Although nonbiological origins for the discoidal impressions cannot be completely discounted, the structures resembling trace fossils clearly have a biological origin and suggest the presence of vermiform, mucus-producing, motile organisms.