Fossil Ginkgo Research Articles

Machine‐learning‐based morphological analyses of leaf epidermal cells in modern and fossil ginkgo and their implications for palaeoclimate studies

AbstractLeaf stomata form an essential conduit between plant tissue and the atmosphere, thus presenting a link between plants and their environments. Changes in their properties in fossil leaves have been studied widely to infer palaeo‐atmospheric‐CO2 in deep time, ranging from the Palaeozoic to the Cenozoic. Epidermal cells of leaves, however, have often been neglected for their usefulness in reconstructing past‐environments, as their irregular shape makes the manual analyses of epidermal cells a challenging and error‐prone task. Here, we used machine‐learning (using the U‐Net architecture, which evolved from a fully convolutional network) to segment epidermal cells automatically, to efficiently reduce artificial errors. We furthermore applied minimum bounding rectangles to extract length‐to‐width ratios (RL/W) from the irregularly shaped cells. We applied this to a dataset including over 21 000 stomata and 170 000 epidermal cells in 114 Ginkgo leaves from 16 locations spanning three climate zones in China. Our results show negative correlations between the RL/W and specific climatic parameters, suggesting that local temperature and precipitation conditions may have affected the RL/W of epidermal cells. We subsequently tested this methodology and the observations from the modern dataset on 15 fossil ginkgoaleans from the Lower to the Middle Jurassic (China). It suggested that the RL/W values of fossil ginkgo generally had a similar negative response to warmer climatic backgrounds as modern G. biloba. The automated analyses of large palaeo‐floral datasets provide a new direction for palaeoclimate reconstructions and emphasize the importance of hidden morphological characters of epidermal cells in ginkgoaleans.

Dinosaur and tree-line invasion of southeastern Australia during Cretaceous greenhouse spikes

The paleosol record of the Early Cretaceous Wonthaggi and Eumeralla formations of Victoria reveals a suite of non-calcareous Histosols and Ultisols, as well as stump casts, indicative of humid temperate ecosystems. At some stratigraphic levels, frigid temperatures are indicated by clastic dykes (ice wedges), load casts of mud (periglacial convolutions), and coal-mantled stone rolls (aapamires). The largest tree stumps and thickest paleosols correspond to known Early Cretaceous greenhouse spikes, as revealed by stomatal index of fossil ginkgo leaves, by black shales of oceanic anoxic events, and both marine and non-marine carbon isotopic anomalies. Temperature and CO2 spikes coincide with appearance of broadleaf deciduous forests, including Ginkgo australis, with dinosaurs, monotremes, placentals, early birds and angiosperms. In contrast, permafrost paleosols represent fern-lycopsid tundra and coniferous taiga vegetation. Early Cretaceous CO2 greenhouse spikes allowed southward migration of tree lines and polar biomes several times during the Cretaceous, which was not continuously a hothouse period. The same greenhouse spikes are recorded by maximal marine transgressions in the Great Artesian Basin of Queensland, and the frigid intervals by dropped pebbles and glendonites in South Australia, New South Wales and Arctic regions.

Temporal Dynamic Transcriptome Landscape Reveals Regulatory Network During the Early Differentiation of Female Strobilus Buds in Ginkgo biloba.

Reproductive bud differentiation is one of the most critical events for the reproductive success of seed plants. Yet, our understanding of genetic basis remains limited for the development of the reproductive organ of gymnosperms, namely, unisexual strobilus or cone, leaving its regulatory network largely unknown for strobilus bud differentiation. In this study, we analyzed the temporal dynamic landscapes of genes, long non-coding RNAs (lncRNAs), and microRNAs (miRNAs) during the early differentiation of female strobilus buds in Ginkgo biloba based on the whole transcriptome sequencing. Results suggested that the functions of three genes, i.e., Gb_19790 (GbFT), Gb_13989 (GinNdly), and Gb_16301 (AG), were conserved in both angiosperms and gymnosperms at the initial differentiation stage. The expression of genes, lncRNAs, and miRNAs underwent substantial changes from the initial differentiation to the enlargement of ovule stalk primordia. Besides protein-coding genes, 364 lncRNAs and 15 miRNAs were determined to be functional. Moreover, a competing endogenous RNA (ceRNA) network comprising 10,248 lncRNA-miRNA-mRNA pairs was identified, which was highly correlated with the development of ovulate stalk primordia. Using the living fossil ginkgo as the study system, this study not only reveals the expression patterns of genes related to flowering but also provides novel insights into the regulatory networks of lncRNAs and miRNAs, especially the ceRNA network, paving the way for future studies concerning the underlying regulation mechanisms of strobilus bud differentiation.

Deep time perspective on rising atmospheric CO2

Abstract The accuracy of CO2 hindcasting using fossil Ginkgo stomatal index is ripe for revision for three reasons: exponential rise in atmospheric CO2 over the past decade, discovery of a Kew herbarium specimen of Ginkgo picked in 1754, and increased sophistication of a pedogenic CO2 paleobarometer as an independent parallel record. Past mass extinctions coincide with revised CO2 spikes of 1500 ppm or more. Increases such as the middle Miocene level of 640 ± 71 ppm expected before the year 2100 resulted in biome shifts, with expansion of tropical forests northward, and of grasslands into deserts. Deep time records from paleosols and from stomatal index reveal that CO2 levels less than 180 ppm and more than 1500 ppm are toxic to the biosphere.

Improving the Ginkgo CO2 barometer: Implications for the early Cenozoic atmosphere

Stomatal properties of fossil Ginkgo have been used widely to infer the atmospheric concentration of CO2 in the geological past (paleo-pCO2). Many of these estimates of paleo-pCO2 have relied on the inverse correlation between pCO2 and stomatal index (SI – the proportion of epidermal cells that are stomata) observed in recent Ginkgo biloba, and therefore depend on the accuracy of this relationship. The SI-pCO2 relationship in G. biloba has not been well documented, however.Here we present new measurements of SI for leaves of G. biloba that grew under pCO2 from 290 to 430 ppm. We prepared and imaged all specimens using a consistent procedure and photo-documented each count. As in prior studies, we found a significant inverse relationship between SI and pCO2, however, the relationship is more linear, has a shallower slope, and a lower correlation coefficient than previously reported. We examined leaves of G. biloba grown under pCO2 of 1500 ppm, but found they had highly variable SI and a large proportion of malformed stomata. We also measured stomatal dimensions, stomatal density, and the carbon isotope composition of G. biloba leaves in order to test a mechanistic model for inferring pCO2. This model overestimated observed pCO2, performing less well than the SI method between 290 and 430 ppm.We used our revised SI-pCO2 response curve, and new observations of selected fossils, to estimate late Cretaceous and Cenozoic pCO2 from fossil Ginkgo adiantoides. All but one of the new estimates is below 800 ppm, and together they show little long-term change in pCO2 or relation to global temperature. The low Paleogene pCO2 levels indicated by the Ginkgo SI proxy are not consistent with the high pCO2 inferred by some climate and carbon cycle models. We cannot currently resolve the discrepancy, but greater agreement between proxy data and models may come from a better understanding of the stomatal response of G. biloba to elevated pCO2, better counts and measurements of fossil Ginkgo, or models that can simulate greenhouse climates at lower pCO2.

Aptian and Albian atmospheric CO2 changes during oceanic anoxic events: Evidence from fossil Ginkgo cuticles in Jilin Province, Northeast China

The Early Cretaceous was a time with super-greenhouse conditions and episodic global oceanic anoxic events. However, relative timing of atmospheric CO2 emissions and oceanic anoxic events, and their causal relationships remain matters of debate. Using the stomatal index approach, well-preserved fossil cuticles of Ginkgo from the Lower Cretaceous Changcai Formation, eastern Jilin, and from the Lower Cretaceous Yingcheng Formation, central Jilin, Northeast China, were investigated to reconstruct atmospheric CO2 concentrations during the Aptian and earliest Albian (Early Cretaceous). The results indicate that the CO2 concentrations reached 1098–1142 ppmv (Carboniferous standardization) or 970–1305 ppmv (regression function) during the Aptian and earliest Albian. Our estimates of palaeoatmospheric CO2 concentrations during the earliest Albian (OAE 1b) are slightly higher than the data between the early Aptian Selli (OAE 1a) and the middle Aptian Fallot OAEs; this may indicate the absence of any great emissions of CO2 during the latest Aptian and earliest Albian.

An antifungal protein from Ginkgo biloba binds actin and can trigger cell death.

Ginkbilobin is a short antifungal protein that had been purified and cloned from the seeds of the living fossil Ginkgo biloba. Homologues of this protein can be detected in all seed plants and the heterosporic fern Selaginella and are conserved with respect to domain structures, peptide motifs, and specific cysteine signatures. To get insight into the cellular functions of these conserved motifs, we expressed green fluorescent protein fusions of full-length and truncated ginkbilobin in tobacco BY-2 cells. We show that the signal peptide confers efficient secretion of ginkbilobin. When this signal peptide is either cleaved or masked, ginkbilobin binds and visualizes the actin cytoskeleton. This actin-binding activity of ginkbilobin is mediated by a specific subdomain just downstream of the signal peptide, and this subdomain can also coassemble with actin in vitro. Upon stable overexpression of this domain, we observe a specific delay in premitotic nuclear positioning indicative of a reduced dynamicity of actin. To elucidate the cellular response to the binding of this subdomain to actin, we use chemical engineering based on synthetic peptides comprising different parts of the actin-binding subdomain conjugated with the cell-penetrating peptide BP100 and with rhodamine B as a fluorescent reporter. Binding of this synthetic construct to actin efficiently induces programmed cell death. We discuss these findings in terms of a working model, where ginkbilobin can activate actin-dependent cell death.

DNA fingerprints of living fossil Ginkgo biloba by using ISSR and improved RAPD analysis

In this study, we have aimed to genetically characterize Ginkgo biloba. Nine G. biloba samples from different places of China were collected, and DNA was extracted from the leaves of these samples for inter-simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) analysis. ISSR analysis showed high genetic variation among the nine varieties of G. biloba; the polymorphism and similarity coefficients were 87% and 0.40–0.84, respectively. RAPD analysis also showed 93% polymorphism, and the similarity coefficients ranged from 0.44 to 0.87. Persistent genetic isolation that developed for millions of years might influence the genetic variability between the samples of G. biloba. This study generates a genetic map of G. biloba, and reports the highly variable intra-species genetic characteristics of this living fossil among different geographical locations of China. Our study also suggests that ISSR and the improved RAPD markers are useful molecular tools for the genetic characterization of plants.

Molecular cloning of two novel peroxidases and their response to salt stress and salicylic acid in the living fossil Ginkgo biloba.

Peroxidase isoenzymes play diverse roles in plant physiology, such as lignification and defence against pathogens. The actions and regulation of many peroxidases are not known with much accuracy. A number of studies have reported direct involvement of peroxidase isoenzymes in the oxidation of monolignols, which constitutes the last step in the lignin biosynthesis pathway. However, most of the available data concern only peroxidases and lignins from angiosperms. This study describes the molecular cloning of two novel peroxidases from the 'living fossil' Ginkgo biloba and their regulation by salt stress and salicylic acid. Suspension cell cultures were used to purify peroxidases and to obtain the cDNAs. Treatments with salicylic acid and sodium chloride were performed and peroxidase activity and gene expression were monitored. A novel peroxidase was purified, which preferentially used p-hydroxycinnamyl alcohols as substrates and was able to form dehydrogenation polymers in vitro from coniferyl and sinapyl alcohols. Two peroxidase full-length cDNAs, GbPrx09 and GbPrx10, were cloned. Both peroxidases showed high similarity to other basic peroxidases with a putative role in cell wall lignification. Both GbPrx09 and GbPrx10 were expressed in leaves and stems of the plant. Sodium chloride enhanced the gene expression of GbPrx09 but repressed GbPrx10, whereas salicylic acid strongly repressed both GbPrx09 and GbPrx10. Taken together, the data suggest the participation of GbPrx09 and GbPrx10 in the developmental lignification programme of the cell wall. Both peroxidases possess the structural characteristics necessary for sinapyl alcohol oxidation. Moreover, GbPrx09 is also involved in lignification induced by salt stress, while salicylic acid-mediated lignification is not a result of GbPrx09 and GbPrx10 enzymatic activity.

Antimicrobial, antioxidant activity and phytochemical analysis of an endophytic species of Nigrospora isolated from living fossil Ginkgo biloba

Nigropsora sp. was isolated as an endophyte from a medicinal plant, Ginkgo biloba. Ethyl acetate extract of the fungus was evaluated for antimicrobial and free radical scavenging (DPPH) activity. Ethyl acetate extract was effective against Escherichia coli (R-2046), Klebsiella sp. (R2434), Staphylococcus aureus (ATCC 6538), Candida albicans (NCIM 3471) and Geotrichum sp. (NFCCI- 2521) while it did not show activity against Saccharomyces cerevisiae (NFCCI-1248), Nodulisporium sp. (NFCCI- 2264) and Syncephalastrum sp. (NFCCI-2269). The minimum inhibitory concentration (MIC) of ethyl acetate extract evaluated by tube broth dilution method was recoerded as 2.5mg/ml against all test organisms while by agar dilution method it was recorded as 1.25mg/ml against E. coli, 0.15625mg/ml against S. aureus and 0.3125mg/ml against Klebsiella sp. and C. albicans. The TLC-bioautography assay, used to screen the plant extracts for antimicrobial activity and localization of the active compounds indicated the presence of a number of inhibitory compounds with activity against tested microorganisms. Phytochemical analysis revealed the presence phenolic compounds and anthraquinones. Nigrospora sp. was also examined for in vitro antioxidant activity by DPPH radical scavenging assay. The ethyl acetate extract of the fungus showed potent antioxidant activity with IC50 value of 9.28µg/ml compared to the IC50 value of standard ascorbic acid, 1.74μg/ml.

773. GINKGO BILOBA - Connections with people and art across a thousand years

Summary. WereviewtherepresentationofGinkgobilobaL.,aquintessentially Chinese plant, in the art of those Western botanists who first encountered it in China and Japan. We also show how several later representations of Ginkgo ,i n both the West and the East, were inspired and made possible by specimens of Ginkgo in cultivation. In a rapidly changing world, a thousand years seems a vast span of time. Yet Ginkgo biloba L. has seen thousands of millennia come and go. In the past, Ginkgo and its fossil cousins were widespread: fossil Ginkgo leaves are known from every continent. Just a few million years ago Ginkgo grew in Europe and also in North America (Crane, 2013). Today, however, Ginkgo is a botanical oddity, a single species with no close living relatives. With its iconic fan shaped leaves, and twigs that show strong differentiation into long and short shoots, it is one of the most distinctive of China’s deciduous trees. The association of Ginkgo with people is documented for about a thousand years in China, where Ginkgo survives in a few potentially relict populations. The early cultivation of Ginkgo focused on its use as a nut tree, and it was probably for this purpose that the tree was grown widely, and then later transplanted to Japan and Korea. One of the Chinese common names for Ginkgo is ‘silver apricot’. Ginkgo was introduced into the West in the mid-18th century and the ‘Old Lion’ at Kew, which dates from the early 1760s, is one of the oldest in cultivation (Crane, 2013). By the mid 19th century Ginkgo was widely grown in Europe, and as early as 1815 Ginkgo was celebratedbyJohannWolfgangvonGoetheinoneofhismostfamous poems (Unseld, 2003). In the late 19th and early 20th centuries, with the recognition that fertilization in Ginkgo differed from that in other trees in being mediated by motile sperm rather than a pollen tube, and with growing recognition of its long fossil record, it became clear that Ginkgo was important in plant evolution and a living link to primeval landscapes that have long since disappeared.

Revision of the genus Grenana Samylina from the Middle Jurassic of Angren, Uzbekistan

The revision of the material from the Middle Jurassic sediments of Angren (Uzbekistan), comprising leaves, collar complexes, and seeds originally described together as a new putative pteridosperm genus GrenanaSamylina (1990), suggests a ginkgoalean affinity of these plant remains. Morphological and epidermal characters of Grenana leaves fit the diagnosis of Sphenobaiera Florin, on the basis of which a new combination Sphenobaiera angrenica comb. nov. is designated, turning the generic name Grenana into a younger synonym of Sphenobaiera. “Grenana” collar complexes, considered by Samylina to represent ultimate leaf segments with terminal cupules, are reinterpreted as compound generative axes consisting of peduncles, pedicels, and collars, and similar to female fructifications of the modern and fossil Ginkgo L. A new genus Nagrenia gen. nov. and species Nagrenia samylinae sp. nov. are erected to accommodate this kind of remains. It is confirmed that leaves and collar complexes share a similar epidermal pattern and thus likely represent parts of the same plant. Seeds of three types, all with characteristic ginkgoalean structure, are discovered in association with the leaves of S. angrenica comb. nov. Two kinds of seeds are placed within Allicospermum Harris and one in Ginkgo; a new species Allicospermum angrenicum sp. nov. is described.

Evidence for the persistence of wild Ginkgo biloba (Ginkgoaceae) populations in the Dalou Mountains, southwestern China

The possible persistence of wild Ginkgo biloba populations in China has long been debated but never scientifically confirmed. We test our hypothesis that the extant Ginkgo populations in the Dalou Mountains (SW China) represent fragments of the original natural Ginkgo range and offer a range of pertinent perspectives on the living fossil Ginkgo's history, prehistory, ecology, and place in human culture-all important aspects of this highly valued species. We analyzed the vegetation of the study area, determined the population age structure of Ginkgo, and compared it to existing fossil records. For supporting material, we also examined records of the lack of human presence before the mid-17th century in the area, the local people's beliefs regarding preservation of the forests and existing genetic studies. Current species composition of Ginkgo forests in the Dalou Mountains agrees closely with floristic assemblages from fossil records bearing G. biloba. Current populations are found in habitats similar to those of fossil Ginkgo, which, as today, favored rock crevices. Female to male ratios are 3:2. Estimated ages for many of the trees show that Ginkgo was present in this area prior to human settlement and indigenous peoples of this area are unlikely to have planted Ginkgo because of traditional beliefs. Our results agree with existing genetic studies that show that these mountains were glacial refugia for G. biloba. The corroborative evidence confirms the finding that these populations represent fragments of the original natural Ginkgo in the valley and lower mountain slopes of the Dalou Mountains.

Ginkgo Huolinhensis sp. nov. from the Lower Cretaceous of Huolinhe Coal Field, Inner Mongolia, China

Abstract:A new species, Ginkgo huolinhensis sp. nov., with well‐preserved cuticle from the Lower Cretaceous, Huolinhe Formation of Huolinhe Coal Field in Inner Mongolia, China, was studied morphologically and anatomically. The main characters of the new species are found in the leaves which are deeply dissected with narrow lobes, trichomes developed on both upper and lower epidermal cells, a media papilla developed on the periclinal walls for each cell in upper cuticle, and no trichomes on the cuticle of the petioles. These characters of G. huolinhensis sp. nov. distinguish from the known species of Ginkgo previously reported. This study of the new species is beneficial for the taxonomic research of fossil Ginkgo, and should be helpful for a better understanding the paleoenvironment of Ginkgo living in northeastern China during the Early Cretaceous.

Estimating paleoatmospheric pCO 2 during the Early Eocene Climatic Optimum from stomatal frequency of Ginkgo, Okanagan Highlands, British Columbia, Canada

Estimates of pCO 2 for the early Paleogene vary widely, from near modern-day levels to an order of magnitude greater, based on various proxy measures. Resolving the relationship between climate and pCO 2 during this globally warm period is a key task in understanding climate dynamics in a warmer world. Here, we use the stomatal frequency of fossil Ginkgo adiantoides from the Okanagan Highlands of British Columbia, Canada to estimate pCO 2 during the Early Eocene Climatic Optimum (EECO), the interval of peak warmth in the Cenozoic. We also examine a dataset of modern Ginkgo biloba leaves to critically assess the accuracy and precision of stomatal frequency as a proxy indicator of pCO 2. Early Eocene fossil G. adiantoides has significantly lower stomatal frequency than modern G. biloba, suggesting pCO 2 levels > 2× modern pre-industrial values. This result is in contrast to earlier studies using stomatal frequency of Ginkgo that indicated near modern-day levels of pCO 2 in the early Paleogene, though not including samples from the EECO. We also find that levels of pCO 2 as indicated by stomatal frequency are correlated with trends in climate (mean annual temperature) over time at the Falkland fossil locality, suggesting that climate and pCO 2 were coupled during the EECO hyperthermal.

A new Tertiary Ginkgo (Ginkgoaceae) from the Wuyun Formation of Jiayin, Heilongjiang, northeastern China and its paleoenvironmental implications

The living fossil Ginkgo, a relict of a once dominant gymnosperm, existed and flourished early in the Mesozoic, but only a vague outline of its evolutionary history in the Tertiary has been unveiled. Here we describe a new species, Ginkgo jiayinensis sp. nov., from the Wuyun Formation of Jiayin, China, which is another well-established Tertiary species based on leaf fossils besides G. adiantoides. The most remarkable feature of the new species is the amphistomatic leaves, likely representing a distinct evolutionary line of the genus in this time interval. Ginkgo jiayinensis is similar to the co-occurring G. adiantoides and extant G. biloba in the lower cuticle, but the two latter species clearly differ in having hypostomatic leaves. Ginkgo biloba is used as the nearest living equivalent (NLE) species for both G. adiantoides and G. jiayinensis in reconstructing paleo-CO(2), as it has been used for other fossil species with either hypostomatic or amphistomatic leaves. The two Tertiary species are almost identical in stomatal index in abaxial cuticles (8.4 and 8.5, respectively), showing no strong differences in response to atmospheric CO(2). Amphistomatic G. jiayinensis would therefore have used a different ecological strategy from that of G. adiantoides of the same bed.

A physiologically explicit morphospace for tracheid-based water transport in modern and extinct seed plants

We present a morphometric analysis of water transport cells within a physiologically explicit three-dimensional space. Previous work has shown that cell length, diameter, and pit resistance govern the hydraulic resistance of individual conducting cells; thus, we use these three parameters as axes for our morphospace. We compare living and extinct plants within this space to investigate how patterns of plant conductivity have changed over evolutionary time. Extinct coniferophytes fall within the range of living conifers, despite differences in tracheid-level anatomy. Living cycads, Ginkgo biloba, the Miocene fossil Ginkgo beckii, and extinct cycadeoids overlap with both conifers and vesselless angiosperms. Three Paleozoic seed plants, however, occur in a portion of the morphospace that no living seed plant occupies. Lyginopteris, Callistophyton, and, especially, Medullosa evolved tracheids with high conductivities similar to those of some vessel-bearing angiosperms. Such fossils indicate that extinct seed plants evolved a structural and functional diversity of xylem architectures broader, in some ways, than the range observable in living seed plants.

Greenhouse crises of the past 300 million years

Proxies of past CO 2 and climate over the past 300 m.y. now reveal multiple global climate change events in unprecedented detail. Evidence for past CO 2 spikes comes from expanded and refined data on stomatal index of fossil Ginkgo and related leaves. New evidence for synchronous climatic change comes from paleosols in Montana, Utah, and neighboring states. Each CO 2 spike was coeval with unusually clayey, red and decalcified paleosols, which can be traced throughout the Colorado Plateau. Spikes in atmospheric CO 2 also were coeval with increases in paleosol alkali depletion as an indication of high temperature, and spikes in paleosol base depletion and depth to calcic horizons as indications of high precipitation. In the Colorado Plateau, times of warmer climate were also more humid, perhaps due to greater moisture potential of warmer air. Seasonality of climate did not increase during warm-wet spikes. The Mesozoic greenhouse was not persistently hot with cool spells, but warm with hot flashes. These data furnish power laws predicting the sensitivity and magnitude of change in mean annual temperature (MAT) and mean annual precipitation (MAP) due to rising CO 2 in a mid-latitude, mid-continental region. The magnitude of the coming anthropogenic greenhouse pales in comparison with past greenhouse spikes at times of global mass extinctions.

Fossil plant evidence for Early and Middle Jurassic paleoenvironmental changes in Lanzhou area, Northwest China

Estimating the paleoclimate changes through CO 2 levels has become a promising area of geological research. This paper focuses on analysis of fossil Ginkgo in continuous sedimentary series in northwestern China using plant anatomy and organic geochemistry approaches. The CO 2 variation curve during Early and Middle Jurassic is reconstructed based on the stomatal ratio method, which is consistent with the estimated results of GEOCARB III. In comparison with the carbon isotopic composition measured from the fossil leaves of Ginkgo, we suggest that the stomata-based CO 2 concentrations for the Jurassic are generally consistent with the predictions of the geochemical model, ranging from 1000 to 1600 ppmv. Measurements of carbon isotope values demonstrate that the water use efficiency of the fossil Ginkgo in a “green house” world is higher than that of the living Ginkgo. Investigations of physiological responses of plants to the increasing CO 2 level at the present and in the future should help demonstrate this effect. The cause of the carbon isotopic shift at the boundary between Aalenian and Bajocian for the Yaojie Basin is unclear and therefore needs further investigation.

Eleven novel microsatellite markers developed from the living fossil Ginkgo biloba (Ginkgoaceae)

Ginkgo biloba L. (Ginkgoaceae), a famous and widely cultivated plant, is often referred to as a living fossil. Here we isolated and characterized 11 polymorphic microsatellite loci from G. biloba using a modified biotin-capture method. These loci showed high levels of allelic diversity, alleles sizes ranged from 4 to 16 per locus with polymorphism information content ranging from 0.432 to 0.909 (average = 0.752). The observed and expected heterozygosities ranged from 0.208 to 0.708 (average = 0.484) and from 0.501 to 0.934 (average = 0.795), respectively. These microsatellite markers can be used as genetic markers for further studies on genetic diversity, genetic structure and the gene flow among populations of this species.