Higher Land Plants Research Articles

A land plant phylogenetic framework for GLABROUS INFLORESCENCE STEMS (GIS), SUPERMAN, JAGGED and allies plus their TOPLESS co-repressor

Members of the plant specific family of C1-1i zincfinger transcriptionfactors (ZF-TFs), such as SUPERMAN, JAGGED, KNUCKLES or GIS,regulatediversedevelopmental processes including sexual reproduction. C1-1is consist of one zinc-finger and one to two EAR domains, connected by large intrinsically disordered regions (IDR). While the role of C1-i1 ZF-TFs in development processes is well known for some genes in Arabidopsis, rice or tomatoa comprehensive and broadphylogenetic background is lacking, yet knowledge of orthology is a requirement for a better understanding of C1-1i-Zf-TFs diverse roles in plants. Here, we provide a fine-grained and land plant wide classification of C1-1i sub-families and their known co-repressors TOPLESS and TOPLESS RELATED. Our work combines the identification of orthologous groups with Maximum-Likelihood phylogeny reconstructions and digital gene expression analyses mining high quality land plant genomes and transcriptomes to generate a comprehensive framework of C1-1i ZF-TF evolution. We show that C1-1i’s are low to moderate copy genesand that orthologous genesonly partiallyhaveconserved sub-family and life cycle stage dependent expression pattern across land plants while others are highly diverged. Our workprovides the phylogenetic framework for C1-1i ZF-TFs, s and strengthen C1-1 ZF-TFs as a potential model for IDR-research in plants.

Intensified bacterial productivity during the Paleocene–Eocene thermal maximum: Molecular evidence in the Tarim Basin in the eastern Tethyan realm

The investigation of bulk and molecular compositions in organic matter at the Bashibulake Section in the SW Tarim Basin, West China, across the Paleocene–Eocene boundary reveals a complex mixture of marine and terrigenous origins during the Paleocene–Eocene Thermal Maximum (PETM) in the eastern Tethys. Source-related biomarkers, such as n-alkanes, isoprenoid alkanes, steranes, hopanes and methylhopanes, exhibit diverse compositions influenced by both marine and terrigenous sources. Sterane and hopane isomer distributions, indicative of immature OM, are primarily controlled by biological configurations. Changes in compound class abundance and isomer ratios reflect variations in source inputs and depositional conditions. Elevated concentrations of n-alkanes from higher plants, along with ratios of C29-C32 moretanes/hopanes and C31/C32 homohopanes, suggest increased terrigenous OM supply during the PETM. However, the significant differences in concentration between n-alkanes from higher land plants and bacterial hopanes, coupled with the presence of 2α-methylhopanes, prevalence of C27 compounds in regular steranes, and absence of oleanane suggest a dominant aquatic bacterial contribution. The study highlights the role of enhanced continental flux and warming in stimulating microbial activity, enriching OM, a factor often overlooked by other analytical methods. The absence of carbonate carbon and low trisnorhopane isomerization provide supportive evidence of ocean acidification and carbonate dissolution during the PETM. Reduced pregnanes and tricyclic terpanes, along with low degree of hopane and sterane isomerization, indicate rising sea levels and low salinity. The findings emphasize the significance of the biomarker approach in identifying OM origin and characterizing the depositional environment in PETM-related sequences, suggesting a more substantial role of bacterial contributions than previously recognized.

Conserved functions of chromatin regulators in basal Archaeplastida.

Chromatin is a dynamic network that regulates genome organization and gene expression. Different types of chromatin regulators are highly conserved among Archaeplastida, including unicellular algae, while some chromatin genes are only present in land plant genomes. Here, we review recent advances in understanding the function of conserved chromatin factors in basal land plants and algae. We focus on the role of Polycomb-group genes which mediate H3K27me3-based silencing and play a role in balancing gene dosage and regulating haploid-to-diploid transitions by tissue-specific repression of the transcription factors KNOX and BELL in many representatives of the green lineage. Moreover, H3K27me3 predominantly occupies repetitive elements which can lead to their silencing in a unicellular alga and basal land plants, while it covers mostly protein-coding genes in higher land plants. In addition, we discuss the role of nuclear matrix constituent proteins as putative functional lamin analogs that are highly conserved among land plants and might have an ancestral function in stress response regulation. In summary, our review highlights the importance of studying chromatin regulation in a wide range of organisms in the Archaeplastida.

Fire as high-elevation cold adaptation: An evaluation of fuels and Terminal Pleistocene combustion in the Central Andes

The use of fire constitutes an essential cultural adaptation to cold, and archaeological evidence for fire can be expected in high-latitude and high-elevation regions successfully inhabited by modern humans. At Cuncaicha rockshelter (4480 m above sea level, or masl) in the southern Peruvian Andes, evidence for fire is present from the earliest occupation, dating to the Terminal Pleistocene (∼12,500–11,200 cal BP). Yet, the site contains relatively few identifiable carbonized macrobotanical remains useful for identifying plants employed as combustible fuel. Based on a comprehensive review of nearly 40 early Andean archaeological sites above 2500 masl, little is known about fuels used for combustion. To understand fuel selection strategies at Cuncaicha, we conducted a combustion field experiment, evaluating the three highland plant taxa most likely to have been used as combustible fuels: Polylepis rugulosa (queñua) tree branches, Parastrephia spp. (tola) woody shrubs, and Azorella compacta (yareta) cushion plants. Temperature measurements informed on the combustion characteristics and efficiency of each fuel. We then compared the experimentally-produced fire residues to the geoarchaeological evidence from Cuncaicha. The resinous cushion plant yareta, endemic to the high Andes, may have been the primary fuel used at Cuncaicha based on the experiment outcome and the geoarchaeological evidence. Due to its high-temperature and complete combustion, yareta leaves little to no macrobotanical evidence, thus its identification at other Andean sites may require a multi-methodological approach. Because the geographic range of this plant corresponds with most early archaeological sites in the high Andes, yareta may have been a key resource enabling early settlement throughout the region.

Graptolite reflectance anomaly

Thermal maturation is traditionally evaluated based on vitrinite reflectance (VRo) measurements and its relationship to oil and gas generation and diagenetic transformation are ingrained in many basin modeling tools. However, vitrinite derives from higher land plants that evolved in Devonian. In pre-Devonian rocks graptolite reflectance (GR) is the most significant thermal index for establishing thermal maturation. Currently, conversions of GR to VRo equivalent rely on several established linear relationships. This study investigates a continuous thermal evolution of GR during artificial maturation of the Lower Ordovician (Tremadocian) Alum Shale of Estonia. We observe an anomalous breakdown in the gradient of GR versus thermal maturity. The anomaly trend is characterized as a suppressed GR gradient throughout the entire gas window (VRo: 1.0–2.0%). We attribute the suppressed measured GR trend to surface imperfection caused by the generation and evasion of hydrocarbon gases that generate nano-porosity vacuolation of the graptolite tissues. After the gas window, GR resumes its increasing trend with a similar gradient as observed in the pre-gas window, due to continued aromatization and condensation of the organic molecules. The GR anomaly indicates a potential underestimation of thermal maturity up to 0.52%VRo when applying a linear conversion formula between random GR and VRo directly. Therefore, a significant maturity correction should be applied to all legacy GR-based maturity measurements that indicate a gas or post-gas maturity rank.

The Effect of Population Pseudo-Rejuvenation in Adverse Changes in Living Conditions: A Case Study on the Highland Plant Species in the Ukrainian Carpathians

Abstract “Rejuvenation of population” is commonly considered as an increase in the proportion of young individuals in the population. In our opinion, the term “rejuvenation” has to be used in case of an increasing percentage of young individuals providing maintenance or increase of the entire population size. In return, an increasing percentage of young individuals while reducing the number of the entire population should be considered as “pseudo-rejuvenation.” A key feature of rejuvenation is the positive dynamics of the population. Instead, pseudo-rejuvenation is an indicator of negative exogenous or endogenous changes and is evidence of population degradation under adverse environment conditions. The article presents the most common examples of the processes of rejuvenation of populations in different plant species under the influence of anthropogenic and natural factors in the plant communities of the Ukrainian Carpathians. The main causes of rejuvenation and pseudo-rejuvenation of populations of the target plant species have been identified. Studies of population structure changes in situ were performed using both long-term monitoring transects laid 5–40 years ago and in new sites. Transects are located in the alpine, subalpine, and upper forest zones of the Ukrainian Carpathians in the height range of 1200–2000 m a.s.l. The study areas cover the most common alpine and chionophilic communities, some forest and subalpine phytocenoses.

Geochemical Characterization of the Eocene Coal-Bearing Source Rocks, Xihu Sag, East China Sea Shelf Basin, China: Implications for Origin and Depositional Environment of Organic Matter and Hydrocarbon Potential

Eocene coal-bearing source rocks of the Pinghu Formation from the W-3 well in the western margin of the Xihu Sag, East China Sea Shelf Basin were analyzed using Rock-Eval pyrolysis and gas chromatography–mass spectrometry to investigate the samples’ source of organic matter, depositional environment, thermal maturity, and hydrocarbon generative potential. The distribution patterns of n-alkanes, isoprenoids and steranes, high Pr/Ph ratios, abundant diterpanes, and the presence of non-hopanoid triterpanes indicate predominant source input from higher land plants. The contribution of aquatic organic matter was occasionally slightly elevated probably due to a raised water table. High hopane/sterane ratios and the occurrence of bicyclic sesquiterpanes and A-ring degraded triterpanes suggest microbial activity and the input of microbial organisms. Overwhelming predominance of gymnosperm-derived diterpanes over angiosperm-derived triterpanes suggest a domination of gymnosperms over angiosperms in local palaeovegetation during the period of deposition. The high Pr/Ph ratios, the plot of Pr/n-C17 versus Ph/n-C18, the almost complete absence of gammacerane, and the distribution pattern of hopanes suggest that the samples were deposited in a relatively oxic environment. Generally, fluctuation of redox potential is coupled with source input, i.e., less oxic conditions were associated with more aquatic organic matter, suggesting an occasionally raised water table. Comprehensive maturity evaluation based on Ro, Tmax, and biomarker parameters shows that the samples constitute a natural maturation profile ranging from marginally mature to a near peak oil window. Hydrogen index and atomic H/C and O/C ratios of kerogens suggest that the samples mainly contain type II/III organic matter and could generate mixed oil and gas.

Systems identification and characterization of \u03b2-glucuronosyltransferase genes involved in arabinogalactan-protein biosynthesis in plant genomes

Utilizing plant biomass for bioethanol production requires an understanding of the molecular mechanisms involved in plant cell wall assembly. Arabinogalactan-proteins (AGPs) are glycoproteins that interact with other cell wall polymers to influence plant growth and developmental processes. Glucuronic acid, which is transferred to the AGP glycan by β-glucuronosyltransferases (GLCATs), is the only acidic sugar in AGPs with the ability to bind calcium. We carried out a comprehensive genome-wide analysis of a putative GLCAT gene family involved in AGP biosynthesis by examining its sequence diversity, genetic architecture, phylogenetic and motif characteristics, selection pressure and gene expression in plants. We report the identification of 161 putative GLCAT genes distributed across 14 plant genomes and a widely conserved GLCAT catalytic domain. We discovered a phylogenetic clade shared between bryophytes and higher land plants of monocot grass and dicot lineages and identified positively selected sites that do not result in functional divergence of GLCATs. RNA-seq and microarray data analyses of the putative GLCAT genes revealed gene expression signatures that likely influence the assembly of plant cell wall polymers which is critical to the overall growth and development of edible and bioenergy crops.

Paleo-depositional environment, origin and characteristics of organic matter of the Triassic Chang 7 Member of the Yanchang Formation throughout the mid-western part of the Ordos Basin, China

A comprehensive geochemical and petrographic study was performed on 23 clay-rich shale samples collected from 18 wells drilled in the mid-western part of the Ordos Basin to investigate the characteristics and thermal maturity of organic matter as well as the paleo-depositional environment of the Chang 7 Member within the Triassic Yanchang Formation. The samples are characterized by moderate to very high organic carbon (TOC) contents ranging from 0.24% to more than 24.83% (2.72% on average) and total sulfur (TS) contents of 0.06% to 6.51%. Rock-Eval S1 and S2 values range from 0.13 to 3.70 mg HC/g rock and 0.62 to 92.50 mg HC/g rock, respectively, implying good to very good hydrocarbon generation potential for most of the samples. Rock-Eval data and petrographical observations reveal that the kerogen is mainly composed of type II to type III, consisting of a mixture of aquatic and terrigenous organic matter. The aliphatic fractions show variable monomodal to bimodal distributions of normal alkanes. Different parameters such as TOC/TS and molecular biomarker data imply that the Chang 7 member is a typical clay-rich source rock deposited in a sulphate-poor lacustrine to fluvio-deltaic environment under oxic to sub-oxic conditions with substantial input of organic matter derived from higher land plants, mainly conifers. Low values of gammacerane further indicate a low salinity of the paleo-lake. Average Tmax values of 445 °C, vitrinite reflectance values between 0.68% and 0.88%, biomarker parameters, such as sterane ratios of C29 ααα 20S/(20S + 20R) and C29 ββ/(ββ + αα), and maturity indices based on aromatic compounds, indicate a thermal maturity within the oil window for the studied samples, showing some regional variability within the mid-western Ordos Basin.

HIGHER LANDPLANT –DERIVED BIOMARKERS IN LIGHT OILS AND CONDENSATES FROM THE COAL‐BEARING EOCENE PINGHU FORMATION, XIHU SAG, EAST CHINA SEA SHELF BASIN

The Cenozoic Xihu Sag in the East China Sea Shelf Basin contains large reserves of coals together with liquid petroleum derived from coal‐associated sediments. However, the origin of the petroleum is not well understood. In this study, biomarker assemblages in a suite of recently discovered light oils and condensates from the Paleogene succession in the western margin of in the Xihu Sag were investigated using gas chromatography – mass spectrometry. The objectives were to investigate the samples' thermal maturity and the depositional environment of the precursor source rocks which generated the oils. The light oils are believed to have been derived from coaly source rocks in the Eocene Pinghu Formation.Assessment of thermal maturity based on CPI, pristane/n‐C17 ratio and isomerisation ratios of C29 steranes and C31 homohopanes suggest that the hydrocarbons have a relatively low maturity in the early to mid oil generation window. The distribution of isoprenoids relative to n‐alkanes, the high pristane/phytane ratios (5.1–10.7), the almost complete absence of gammacerane and C33+ homohopanes, and the low dibenzothiophene/phenanthrene ratios indicate that the source rocks of the hydrocarbons were deposited in a relatively oxic and sulphate‐poor fluvio‐deltaic environment which was favourable for coal measure development.Abnormally abundant gymnosperm‐derived diterpanes including labdane, 19‐norisopimarane, fichtelite, rimuane, pimarane, isopimarane, 17‐nortetracyclic diterpene, phyllocladanes and abietane were detected in the samples analysed. 16a(H)‐Phyllocladane was identified unambiguously and kauranes were confirmed to be absent. In addition, three 19‐norisopimarane isomers, 13β(H)‐atisane, and 20‐normethylatisane were tentatively identified in the studied samples. The distributions of n‐alkanes, isoprenoids and regular steranes, the presence of 4β(H)‐eudesmane and oleanane, high Pr/Ph ratios and the abundant diterpanes together suggest that the hydrocarbons were derived from a coaly source rock. Gymnosperms of the conifer families Cupressaceae (especially the former Taxodiaceae) and Pinaceae are interpreted to be the major source of the diterpanes and to have made a significant contribution to the coaly source rock. However, the low abundance of oleanane relative to diterpanes may underestimate the contribution from angiosperms relative to gymnosperms. This could be due to differential preservation and alteration of the di‐ and triterpenoid precursors during diagenesis and the occurrence of non‐specific precursors in higher land plants.

Geochemical evaluation of aliphatic and aromatic hydrocarbons in Palaeogene source rocks from the Latrobe Group, Gippsland Basin, Australia

Twenty-seven hydrocarbon source rocks from the Proteacidites asperopolus, Malvacipollis diversus and Lygistepollenites balmei biozones, Palaeogene Latrobe Group in the Gippsland Basin were analysed using gas chromatography-mass spectrometry. Based on the molecular geochemistry of the aliphatic and aromatic fractions, together with bulk geochemical data (including Rock-Eval pyrolysis and total organic carbon contents), the thermal maturity, palaeoenvironments, and organic matter source of these Palaeogene samples were systematically evaluated. The results provide a useful comparison with those from Upper Cretaceous source rocks in the Gippsland Basin (Jiang and George, 2018, 2019). Similar to the Upper Cretaceous rocks, the aliphatic hydrocarbons in the Paleogene samples are mainly comprised of n-alkanes, isoprenoids, terpanes, hopanes and steranes. The aromatic hydrocarbons are dominated by naphthalene, phenanthrene, anthracene, fluorene, dibenzofuran, dibenzothiophene and their alkyl homologues. Other aromatic hydrocarbons detected include land plant-derived compounds (e.g. retene, methylretenes, cadalene, simonellite, etc), and combustion-derived compounds (e.g. chrysene, pyrene, picene, benzo[b]fluoranthene, benzo[a]anthracene, etc). These 4- to 6-ring polycyclic aromatic hydrocarbons are more abundant in the Paleogene samples compared to the Upper Cretaceous rocks. Biomarker and aromatic hydrocarbon distributions indicate that the Proteacidites asperopolus and Malvacipollis diversus samples are immature or are in the early stage of the oil generation window, while the Lygistepollenites balmei samples correspond to the low maturity to mature stage. The samples were all deposited under sub-oxic to oxic conditions in fresh water with low salinity, possibly in a lacustrine depositional environment. The organic matter inputs are from plankton/algae and higher land plants, but are dominated by organic matter with a terrigenous origin.

STRATIGRAPHIC FRAMEWORK AND PETROLEUM GEOCHEMISTRY OLIGOCENE SOURCE ROCKS, NORTHERN SONG HONG BASIN

The lacustrine oil-prone organic-rich mudstones in the Oligocene are the most important source rocks which have contributed to generate significant hydrocarbon accumulations in the northern Song Hong basin but still poor understanding due to the limitation of data. Newly c. 800km2 3D seismic data and well data allows investigating the stratigraphy and geochemistry of the northern Song Hong basin in detail to define the stratigraphic framework and hydrocarbon potential. The area is characterized by three relatively elongate grabens which are separated by the northeast-southwest basement faults. The most completed synrift sequence is observed in the central graben and is divided into three distinct sections, lower section (Ol), middle (Om) and upper (Ou), corresponding to three phases defined by tectonic systems tracts, from rift initiation to rift development and finally fill up phase. Uplift at the end of Oligocene has strongly modified the syn-rift sequences, resulting in folding, reactivated some basement faults and generated a series of new EW trending faults which may act as potential structural traps in the area. Organic geochemical analysis of the lacustrine mudstone samples from Ol and Om section of well D-1X shows fair to high organic carbon contents, Total Organic Carbon (TOC) 0.51 - 4.86 wt% and Hydrogen Index (HI) 273 - 552 mg HC/g TOC, corresponding to the type II kerogen. Biomarkers indicate the contribution of algal, high land plant, and bacterial sources to the composition of organic matters. Organic matters were deposited in the less oxic environment, in the fresh-water to brackish marine influence.

Organic geochemical characteristics and organic matter enrichment of mudstones in an Eocene saline lake, Qianjiang Depression, Hubei Province, China

Abstract The Qianjiang Depression is a typical Eocene hypersaline lake basin developing good source rocks in the Qianjiang Formation, which have recently been identified as a potential target for saline lacustrine shale oil exploration. Previous studies have only focused on estimates of source rock potential and reservoir quality. However, studies on organic matter enrichment mechanisms in evaporative environments are limited. Based on organic geochemical and mineralogical data, as well as sedimentological analyses, we researched the factors controlling differences in organic matter enrichment in the basin. The results show that total organic carbon (TOC) contents are closely associated with lithofacies with distinct variations. Three main lithofacies associations (LAs) were identified: (1) glauberite-rich LA1 with medium TOC; (2) carbonate-rich LA2 with high TOC; and (3) anhydrite-rich LA3 with low TOC. The distribution of biomarkers from 14 samples indicate both higher land plants and aquatic organisms were involved in the organic matter accumulations. Combining experimental results on gammacerane/C30 hopane, extended tricyclic terpane ratio (ETR), Sr/Ba, V/Ni, and sedimentary characteristics, we analyzed the sedimentary environments of the three LAs. LA1 was deposited in a salinity stratified waterbody with strong evaporation, LA2 was deposited in a still, stratified deep waterbody, whereas LA3 was deposited in a disturbed, saline waterbody. Sedimentary environments not only controlled the formation of the lithofacies, but also influenced the organic matter sources and preservation. Relatively low salinity, strong anoxic condition without physical disturbance, appropriate nutritional terrigenous material inputs, and algal blooms produced the best organic matter enrichment in the saline lake system.

Hydrocarbon Generation Potential of the Organic-Rich Naifa Formation, Say’un–Masila Rift Basin, Yemen: Insights from Geochemical and Palynofacies Analyses

The Say’un–Masila rift, one of the most important basins of Yemen, contains unconventional resources of organic-rich rocks. In the present work, geochemical and palynofacies analyses were performed on the organic-rich source rock (argillaceous limestone) of the late Jurassic–early Cretaceous Naifa Formation in the Say’un–Masila Rift Basin to investigate its hydrocarbon generation potential. The geochemical analysis of the organic matter reveals that the argillaceous limestone unit has total organic carbon contents of 0.5–2.6%, which indicate fair to good hydrocarbon source potential. The organic matter in the analyzed samples is dominated by Type II/III and Type III kerogens, with minor Type II kerogen, referring to both oil- and gas-prone source rocks. The dominant kerogen Types II/III and Type III are indicated further from quantitative results based on an open pyrolysis–gas chromatography analysis. Biological markers and palynofacies analysis suggest that the kerogen was formed through a combination of mixed marine and high land plant organic matter and was preserved under sub-oxic sedimentary conditions. The different geochemical and optical maturity parameters indicate that the analyzed argillaceous limestone of the Naifa Formation is thermally mature, equivalent to early mature of oil-generation window. This implies that the burial depth of the analyzed samples is not deep enough; therefore, only the deeper parts of the Naifa source rocks at the basin have reached a satisfactory maturity level to be considered as potentially effective petroleum source rock. The biomarker source and depositional environment indicators presented and discussed in this study are useful for future exploration in the Say’un–Masila Basin for oil-to-oil and oil-to-source geochemical correlations and offer guidance for potential prospecting targets that may occur within the basin.

Biomarker signatures of Upper Cretaceous Latrobe Group petroleum source rocks, Gippsland Basin, Australia: Distribution and geological significance of aromatic hydrocarbons

Aromatic hydrocarbons extracted from Upper Cretaceous (Maastrichtian and Campanian) Latrobe Group coaly shales and shales from the Gippsland Basin were investigated by gas chromatography–mass spectrometry. A variety of 2-ring to 6-ring aromatic hydrocarbons were identified, including both higher-plant-derived and combustion-derived polycyclic aromatic hydrocarbons (PAHs). These aromatic compounds indicate that the Upper Cretaceous coaly shales and shales were deposited in a fluvial/deltaic environment with significant higher plant input and are at a relatively low thermal maturity stage. Higher plant parameters and angiosperm/gymnosperm indices based on aromatic components suggest that higher land plants, including both angiosperms and gymnosperms, were an important part of the palaeovegetation in the Upper Cretaceous. The aromatic angiosperm/gymnosperm index that includes chrysene- and picene-type PAHs is not as reliable for evaluation of relative angiosperm and gymnosperm contributions as the aliphatic indices due to input of combustion-derived PAHs and the complexity of burning conditions altering the relative contributions. However, combustion-derived PAHs and aromatic angiosperm/gymnosperm indices supplement the information from aliphatic hydrocarbons and provide further evidence to support the hypothesis that palaeoclimate cooled from the Campanian to the Maastrichtian.

Organic geochemistry of the Early Cretaceous shales, Saar Formation in the East Shabwah oil fields, onshore Masila Basin of eastern Yemen

The early Cretaceous Saar Formation includes potential petroleum-bearing source rocks in the onshore Masila Basin, eastern Yemen. The organic matter input, depositional environment conditions and petroleum generation potential from the Saar Formation shales were investigated using geochemical and organic petrological methods.The shales of the Saar Formation contain total organic carbon of 0.5–3.5 wt percent. The geochemical analysis of the organic matter indicated that these shales have fair to very good hydrocarbon source potential. The kerogen of the organic matter is dominated by Type II/III and Type III, referring to both oil- and gas-prone source rocks. The biomarker and bulk carbon isotope analyses of the organic matter suggested that the kerogens were constituted from a combination of marine and high land plant organic matter, and were preserved under suboxic depositional conditions.The geochemical and petrographic analyses of the shales (e.g., vitrinite reflectance (VRo), pyrolysis Tmax and biomarker maturity ratios) lead to the conclusion that the shales are generally immature to very early mature, particularly in shallower locations where the thermal alteration level of the organic matter is not strong enough to generate petroleum. Therefore, this work suggests that the mature source shale intervals of the Saar Formation existed in the deeper parts of the basin could reach a good maturity level that can produce potential hydrocarbons. Prediction of the potential migration pathways for hydrocarbons produced by deep shales could significantly aid in the future of petroleum exploration in the Masila Basin of Eastern Yemen.

The Importance of Conserved Serine for C-Terminally Encoded Peptides Function Exertion in Apple.

Background: The C-terminally encoded peptide (CEP) family has been shown to play vital roles in plant growth. Although a genome-wide analysis of this family has been performed in Arabidopsis, little is known regarding CEPs in apple (Malus domestica). Methods: Here, a comprehensive bioinformatics approach was applied to identify MdCEPs in apple, and 12 MdCEP genes were identified and distributed on 6 chromosomes. Results: MdCEP1 peptide had an inhibitory effect on root growth of apple seedlings, indicating that MdCEP1 played a negative role in root development. In addition, the serine and glycine residues remained conserved within the CEP domains, and MdCEP1 lost its function after mutation of these two key amino acids, suggesting that Ser10 and Gly14 residues are crucial for MdCEPs-mediated root growth of apple. Encouragingly, multiple sequence alignment of 273 CEP domains showed that Ser10 residue was evolutionarily conserved in monocot and eudicot plants. MdCEP derivative (Ser to Cys) lost the ability to inhibit the root growth of Nicotiana benthamiana, Setaria italic, Samolous parviflorus, and Raphanus sativus L. and up-regulate the NO3− importer gene NRT2.1. Conclusion: Taken together, Ser10 residue is crucial for CEP function exertion in higher land plants, at least in apple.

Diverse Sedimentary Conditions During Deposition Of Coal And Oil Shale From The Meihe Basin (Eocene, Ne China)

The Meihe Basin in northeastern China is a normal-fault-controlled basin filled with Eocene nonmarine deposits, the sediments assigned to the Meihe Formation. Sediment grain-sizes, core study, well-log analysis and micropetrographic study combined with sedimentary facies analysis indicate that the main sedimentary facies of the Meihe Basin represent fan-delta, lake, and turbidite deposits. Thick coal seams that are mainly distributed in the eastern part of the studied area were deposited in the swamp facies of the Lower Coal-Bearing Member. Oil shale was mainly deposited in the deep lake represented by the Mudstone Member, and is mainly distributed in the southern part of the studied area. In the Lower Coal-Bearing Member, organic-rich sediments are characterized by TOC content between 0.6 wt.% and 43.1 wt.%and contain Type II and III kerogen. The thick coal seams are the result of high landplant productivity and good preservation conditions. Thin coal seams in the fan-delta plain resulted from the migration and erosion of the fan-delta channel. In the shallow lake and fan-delta front, limited productivity coupled with dilution by inorganic matter resulted in lower organic-matter content in theMudstoneMember. Oil shale and mudstone rich in organic matter were deposited in a deep lake with an average TOC content of 3.4 wt.%. The origin of the organic matter was mainly algae and aquatic plants mixed with land plants. The improved preservation conditions and high bioproductivity in this environment resulted in three oil-shale layers in the lower part of this sedimentary succession. Three coal-bearing and oil-shale-bearing fault basins lie adjacent to the Dunhua-Mishan Fault zone, among which the Fushun Basin is located in the southwest, the Meihe Basin is in themiddle, and theHuadian Basin is in the southeast. From the Fushun Basin to the Huadian Basin, the oil shale and coal seams have distinct sedimentation characters laterally. Vertically in each basin, the organic-matter sources all have the same variation trend from land plants to land plants mixed with algae to algae then to algae mixed with land plants, and the TOC content also shows a similar trend from high to medium-high then to low in each basin.

Paleoenvironmental implications of Holocene long-chain n-alkanes on the northern Bering Sea Slope

The records of high-resolution terrestrial biological markers (biomarkers) from Core B2-9 from the northern Bering Sea Slope over the last 9.6 ka BP were presented in the study. Variations in input of terrestrial long-chain nalkanes (referred to as n-alkanes) and vegetation structure in their source regions were investigated. The results show that the nC27 is the main carbon peak and has the greatest contribution rate of the total n-alkane content; this might be related to the abundance of woody plants and their spatial distribution in the source region. nC23 is another n-alkane having a relatively high content; this was mainly derived from submerged plants widespread along the coastal areas in the northern hemisphere. Total n-alkane content dropped quickly at ca. 7.8 ka BP, ca. 6.7 ka BP and ca. 5.4 ka BP, and was followed by four relatively stable stages mostly controlled by sea-level rise, climate change and vegetation distribution in the source region. Variation in carbon preference index (CPI) indicates that the n-alkanes primarily originated from higher land plants, and the average chain length (ACL) and nC31/nC27 ratio reveal the relatively stable presence of woody/herbaceous plants during the Holocene, and dominate woody plants in most of the time. Simultaneous variation in total n-alkane content, nC27 content and its contribution, CPI, ACL and nC31/nC27 ratio over several short periods suggest that the growth rate of the woody plant n-alkane contribution was lower than that of herbaceous plants and fossil n-alkanes under the particular climatic conditions of the source region.

Source rock characteristics of the Early Cretaceous Garau and Gadvan formations in the western Zagros Basin\u2013southwest Iran

Cretaceous source succession in the Zagros Basin comprises the Garau, Gadvan, and Kazhdumi formations, which have probably generated most of the oil and associated gas in the region. In the following study, the generation potential as well as maturity, molecular, and isotopic characteristics of the Early Cretaceous source rocks (Garau and Gadvan formations) in southwest Iran were investigated. One hundred and forty core and cutting samples of Early Cretaceous sediments were obtained from 24 wells in 12 oil fields from the northern Dezful Embayment and Abadan plain. Geochemical measurements such as Rock–Eval pyrolysis, vitrinite reflectance, GC, GC–MS, and isotopic studies were conducted on selected samples. The results have shown that the Gadvan Formation, with an average TOC of 0.65 wt% and HI values of 122 mgHC/g TOC, can be classified as poor source rock, while the Garau Formation, with TOC and HI values of up to 5.72 wt% and 413 mgHC/g TOC, respectively, can be considered as having good to excellent source potential. Kerogen in the Gadvan Formation belongs to Type III/II, while kerogen in the Garau Formation belongs to Type II. Samples from the Gadvan Formation are at the beginning of oil generation, while the current maturity of the Garau samples is already in the peak oil generation stage. Maturity in the studied samples increases eastward toward the Dezful Embayment. GC, GC–MS and isotopic values for the Gadvan Formation indicate high land plant contribution, low maturity, and oxic to sub-oxic depositional environment of the organic matter. In contrast, the Garau Formation shows an advanced level of maturity and marine depositional environment. Considering the results of this study, the Garau Formation, with excellent production potential and a high level of maturity, can be regarded as a source of a huge amount of oil and gas in the region.