Group Of Gymnosperms Research Articles

Disparity of cycad leaves dispels the living fossil metaphor

The living fossil metaphor is tightly linked with the cycads. This group of gymnosperms is supposed to be characterised by long-term morphological stasis, particularly after their peak of diversity and disparity in the Jurassic. However, no formal test of this hypothesis exists. Here, we use a recent phylogenetic framework and an improved character matrix to reconstruct the Disparity Through Time for cycad leaves using a Principal Coordinate Analysis and employing Pre-Ordination Ancestral State Reconstruction to test the impact of sampling on the results. Our analysis shows that the cycad leaf morsphospace expanded up to the present, with numerous shifts in its general positioning, independently of sampling biases. Moreover, they also show that Zamiaceae expanded rapidly in the Early Cretaceous and continued to expand up to the present, while now-extinct clades experienced a slow contraction from their peak in the Triassic. We also show that rates of evolution were constantly high up to the Early Cretaceous, and then experienced a slight decrease in the Paleogene, followed by a Neogene acceleration. These results show a much more dynamic history for cycads, and suggest that the ‘living fossil’ metaphor is actually a hindrance to our understanding of their macroevolution.

Chemophenetic investigation of epicuticular n-alkanes in Juniperus L. section Juniperus L. from the Balkans

Junipers are one of the most diverse groups of gymnosperms today. They are adapted to arid areas of the world. In this study, we analysed the chemical composition of the leaf n-alkanes of 170 individuals belonging to Juniperus communis subsp. communis, J. communis var. saxatilis, J. deltoides and J. macrocarpa from the Balkans. Localities with at least two sympatric populations were chosen to study the chemical composition in order to limit the influence of environmental factors on the chemical composition. The leaf n-alkanes were extracted from the leaves with n-hexane and analysed using GC-MS. In all of the samples, n-C33 was the dominant alkane, with n-C29, n-C31 and n-C35 comprising over 80% of the n-alkane profile. The percentages of these dominant n-alkanes were taxon-specific, thus indicating their chemotaxonomic significance. In all the multivariate statistical analyses, samples belonging to different taxa were separated from each other. While the n-alkane profile can be used as a chemotaxonomic tool in the differentiation of these four taxa, it did not carry a phylogenetic signal. Instead, it reflected ecological adaptations, showing how different taxa have adapted to different arid environments within the study area.

Core Endophytic Bacteria and Their Roles in the Coralloid Roots of Cultivated Cycas revoluta (Cycadaceae).

As a gymnosperm group, cycads are known for their ancient origin and specialized coralloid root, which can be used as an ideal system to explore the interaction between host and associated microorganisms. Previous studies have revealed that some nitrogen-fixing cyanobacteria contribute greatly to the composition of the endophytic microorganisms in cycad coralloid roots. However, the roles of host and environment in shaping the composition of endophytic bacteria during the recruitment process remain unclear. Here, we determined the diversity, composition, and function prediction of endophytic bacteria from the coralloid roots of a widely cultivated cycad, Cycas revoluta Thunb. Using next-generation sequencing techniques, we comprehensively investigated the diversity and community structure of the bacteria in coralloid roots and bulk soils sampled from 11 sites in China, aiming to explore the variations in core endophytic bacteria and to predict their potential functions. We found a higher microbe diversity in bulk soils than in coralloid roots. Meanwhile, there was no significant difference in the diversity and composition of endophytic bacteria across different localities, and the same result was found after removing cyanobacteria. Desmonostoc was the most dominant in coralloid roots, followed by Nostoc, yet these two cyanobacteria were not shared by all samples. Rhodococcus, Edaphobacter, Niastella, Nordella, SH-PL14, and Virgisporangium were defined as the core microorganisms in coralloid roots. A function prediction analysis revealed that endophytic bacteria majorly participated in the plant uptake of phosphorus and metal ions and in disease resistance. These results indicate that the community composition of the bacteria in coralloid roots is affected by both the host and environment, in which the host is more decisive. Despite the very small proportion of core microbes, their interactions are significant and likely contribute to functions related to host survival. Our study contributes to an understanding of microbial diversity and composition in cycads, and it expands the knowledge on the association between hosts and symbiotic microbes.

Komlopteris: A persistent lineage of post-Triassic corystosperms in Gondwana

Komlopteris is a genus that includes the youngest representative of the so-called ‘seed ferns’, an informal group of gymnosperms that were prevalent during the Mesozoic but largely went extinct at the end of the Cretaceous. New fossil material, morphological data, and an extensive literature review allowed us to clarify the systematics of Gondwanan post-Triassic leaves of the Komlopteris lineage that were formerly assigned to diverse genera. Trends in diversity and distribution were identified. Ten species of Komlopteris were recognized in Jurassic to Eocene strata across Gondwana. Earliest records of the genus derive from South America soon after the end-Triassic extinction event. The genus reached its peak diversity and range in the Late Jurassic and Early Cretaceous and declined markedly after the Aptian. Its youngest representation is in mid-Cretaceous to Eocene deposits of southeastern Gondwana. Although never dominant, Komlopteris represents an important subsidiary component of austral Jurassic–Paleogene plant fossil assemblages. Striking morphological similarities to Dicroidium and Kurtziana, and co-occurrence with low concentrations of Alisporites/Falcisporites-type pollen, suggest that Komlopteris was a gymnosperm belonging to Umkomasiales (=Corystospermales) that survived the end-Triassic and end-Cretaceous biotic crises in climatically buffered humid habitats of high southern latitudes. Arthropod induced leaf damage was rare on Komlopteris foliage and recognized only in two Late Jurassic–Early Cretaceous species.

A paleo-bioclimatological study on gondwana coal deposits in northwestern Bangladesh and the associated environment reflected by pollen and geochemical analysis

To comprehend the realistic paleo-bioclimate and depositional environment, we need to clearly grasp the methods that can be used to track paleoclimate in the past. The present research has focused on palynological investigation, X-ray Diffraction analysis, and elemental analysis of the core coal samples of the Gondwana coal of the Barapukuria Basin. The palynological study identifies two Palynoassemblage zones (Zone I and Zone II). A non-striate desiccate Scheuringipollenite, Crucisaccites, Parasaccites palynoassemblages are identified as Zone I and denotes as Lower Barakar Palynozone in the Early Permian where Zone II is dominated by striate desiccate Barakarites, Faunipollenites, Callumispora Palynoassemblages in the Late Permian. The Glossopterid plant family ruled the botanical affinity of Zone I and Zone II. It rendered the Gymnosperm group of plants as the rapid deglaciation assisted dissemination of Glossopteris flora. Higher percentages of clay minerals in X-ray diffraction (XRD) analysis and higher amounts of carbon content, lower sulfur, and higher C/S>10 ratio in the elemental analysis have been identified. All evidence from the research suggests that coals were deposited when glaciers retreated in the Early Permian, and the Gymnosperm group of plants prevailed and accumulated in the warm and humid climatic conditions under the braided fluvial influence in the terrestrial environment. J. Asiat. Soc. Bangladesh, Sci. 49(1): 101-119, June 2023

Paku Epifit pada Gymnospermae di Kebun Raya Cibodas

Epiphytic ferns can be found in host trees from the Angiosperm and Gymnosperm groups. Epiphytic ferns in Angiosperm plants host have been widely studied, but there is little known for Gymnosperm plants host. The aim of this study was to identify the species of epiphytic ferns in the Gymnosperm plants host at Cibodas Botanical Garden and to analyze the diversity of epiphytic ferns based on microclimate conditions and the surface texture of Gymnosperms plants host. Epiphytic ferns diversity data was obtained using purposive random sampling method. Factors that influence the occupancy of ferns are analyzed using Principal Component Analysis. Epiphytic ferns in Gymnosperm host at Cibodas Botanical Garden were identified as 18 species including 7 family. The most dominant species of epiphytic fern is Davallia denticulata (59.45%). Diversity of epiphytic fern on Gymnosperm at Cibodas Botanical Garden is moderate (H’ = 1.81).

The dynamic history of gymnosperm plastomes: Insights from structural characterization, comparative analysis, phylogenomics, and time divergence.

Gymnosperms are among the most endangered groups of plant species; they include ginkgo, pines (Conifers I), cupressophytes (Conifers II), cycads, and gnetophytes. The relationships among the five extant gymnosperm groups remain equivocal. We analyzed 167 available gymnosperm plastomes and investigated their diversity and phylogeny. We found that plastome size, structure, and gene order were highly variable in the five gymnosperm groups, of which Parasitaxus usta (Vieill.) de Laub. and Macrozamia mountperriensis F.M.Bailey had the smallest and largest plastomes, respectively. The inverted repeats (IRs) of the five groups were shown to have evolved through distinctive evolutionary scenarios. The IRs have been lost in all conifers but retained in cycads and gnetophytes. A positive association between simple sequence repeat (SSR) abundance and plastome size was observed, and the SSRs with the most variation were found in Pinaceae. Furthermore, the number of repeats was negatively correlated with IR length; thus, the highest number of repeats was detected in Conifers I and II, in which the IRs had been lost. We constructed a phylogeny based on 29 shared genes from 167 plastomes. With the plastome tree and 13 calibrations, we estimated the tree height between present-day angiosperms and gymnosperms to be ∼380 million years ago (mya). The placement of Gnetales in the tree agreed with the Gnetales-other gymnosperms hypothesis. The divergence between Ginkgo and cycads was estimated as ∼284 mya; the crown age of the cycads was 251 mya. Our time-calibrated plastid-based phylogenomic tree provides a framework for comparative studies of gymnosperm evolution.

Rasapanchakas Assessment of Seeds of a Folk Plant - Gnetum ula Brongn.

Journal of Ayurveda Medical Sciences,2019,4,2,494-502.DOI:10.5530/jams.2019.4.9Published:June 2021Type:Original ArticleAuthors:Ramya Krishna Koliyat Valappil, Tandrady Shridhara Bairy, Koppala Narayana Sunil Kumar, and Sudhakar Author(s) affiliations:Ramya Krishna Koliyat Valappil1, Tandrady Shridhara Bairy2, Koppala Narayana Sunil Kumar3, Sudhakar4 1Department of Dravyaguna, Government Ayurveda College, Kannur, Pariyaram - 670503, Kerala, INDIA. 2Department of PG Studies in Dravyaguna, SDM College of Ayurveda, Kuthpady, Udupi - 574118, Karnataka, INDIA. 3Research officer Scientist 1-Pharmacognosy, Central Council for Research in Siddha, Ministry of AYUSH, Chennai 600106, Tamil Nadu, INDIA. 4SDM Centre for Research in Ayurveda and Allied Sciences, Kuthpady, Udupi - 574118, Karnataka, INDIA. Abstract:Background: Ayurveda opines that every plant has its own medicinal values, but there are many less explored plants which are not popular though beneficial either as food or as medicine. But this knowledge is passed from tradition to tradition in folklore practices but within a few groups of a society. One such plant from gymnosperm group is Gnetum ula Brongn. (Gnetaceae) found commonly in and around Udupi. Locally known as kumti beeja. Seeds are roasted or boiled and consumed as it is said to be very nutritious and having krimighna action by folk practitioners. The present work aimed in such less explored plants for its assessment of Rasapanchakas. Methods: The study conducted was to assess the rasapanchakas of seeds of G.ula in which Rasa was assessed by healthy volunteers of sample size 10 and giving scores. Asessement of guna, and vipaka at the level of dosha, dhatu and mala by using animal model and by the experience documented by the folk lore practioners. Asessment of virya by exothermic, endothermic reactions in distilled water. Results: Study revealed seeds of G. ula having, kashaya as pradhana rasa, anurasa is madhura -tikta, guna is guru, ruksha and ushna. Virya is ushna and vipaka is katu. Conclusion: Folklore medicine has tremendous source of information regarding the utility of locally available plants for both as food and as medicines. Such plants have to be properly explored and scientifically documented before putting it into use. Keywords:Gnetum ula., Guna, Kumti beeja, Rasa, Rasapanchakas, Vipaka, ViryaView:PDF (837.06 KB)

Bennettitalean Leaves From the Permian of Equatorial Pangea—The Early Radiation of an Iconic Mesozoic Gymnosperm Group

Bennettitaleans are an extinct group of gymnosperms that are among the most iconic plants of Earth’s vegetation during the Mesozoic Era. The sudden appearance and rise to dominance of the Bennettitales during the Triassic remains a mystery. Leaf fossils similar to typical bennettitalean foliage occur in late Paleozoic deposits worldwide, but bennettitalean foliage can be identified with certainty only in case the fossils are sufficiently well-preserved to show epidermal features. So far, the characteristic stomatal architecture of the group has never been systematically documented in these putative Paleozoic remains. Here, we present well-preserved bennettitalean leaves from Permian deposits in two widely separated regions of equatorial Pangea. Two species of cuticle-bearing leaf compressions from the late Permian Umm Irna Formation, Jordan, are here formally described asPterophyllum pottiiBomfleur et Kerp sp. nov. andNilssoniopteris jogianaBlomenkemper et Abu Hamad sp. nov. Moreover, bulk maceration of samples from the Umm Irna Formation yielded six additional types of dispersed bennettitalean cuticles that are here informally described. In addition, the Cisuralian (early Permian) uppermost part of the Upper Shihhotse Formation exposed at the Palougou section in Shanxi Province, China, has yielded the oldest unambiguous bennettitalean fossils known to date; they consist of fragments of entire-margined leaves with well-preserved cuticles that we assign toNilssoniopteris shanxiensisBäumer, Backer et Wang sp. nov. Unlike the characteristic puzzle-patterned cuticles typical of many Jurassic and Cretaceous bennettites, the cuticles of these Permian bennettitalean remains show non-sinuous anticlinal walls, greater variety in stomatal orientation, and rare occurrence of transversely divided subsidiary cells—features that have until now almost exclusively been documented from the hitherto oldest cuticle-bearing Triassic bennettitalean material. Finally, the taxonomic richness, disjunct distribution, and broad variety in macro- and micromorphological features in these Permian bennettitalean remains lead us to suspect that the origin of the group will date back still further in time, and might in fact coincide with very early occurrences of Bennettitales-like foliage from the Pennsylvanian and Cisuralian, such asPterophyllum cottaeanum,P. eratum, orP. grandeuryi.

Nutritional and Antioxidant Study of Seeds of A Folk Plant - Gnetum ula Brongn

Journal of Ayurveda Medical Sciences,2019,4,1,467-469.DOI:10.5530/jams.2019.4.4Published:December 2020Type:Short CommunicationAuthors:Ramya Krishna Koliyat Valappil, Tandrady Shridhara Bairy, Koppala Narayana Sunil Kumar, and Sudhakar Author(s) affiliations:Ramya Krishna Koliyat Valappil, Tandrady Shridhara Bairy1, Koppala Narayana Sunil Kumar2, Sudhakar3 Department of Dravyaguna, Government Ayurveda College, Kannur, Pariyaram - 670503, Kerala, INDIA. 1Department of PG Studies in Dravyaguna, SDM College of Ayurveda, Kuthpady, Udupi - 574118, Karnataka, INDIA. 2Department of Pharmacognosy, Siddha Central Research Institute, Siddha Central Research Institute (CCRS, Ministry of AYUSH, Govt of India), Chennai - 600106, Tamil Nadu, INDIA. 3SDM Center for Research in Ayurveda and Allied Sciences, Kuthpady, Udupi - 574118, Karnataka, INDIA. Abstract:Background: Ayurveda opines that every plant has its own medicinal values, but there are many less explored plants which are not popular though beneficial either as food or as medicine. But this knowledge is passed from tradition to tradition in folklore practices but within a few groups of a society. One such plant from gymnosperm group is Gnetum ula Brongn. (Gnetaceae) found commonly in and around Udupi. Locally known as Kumti beeja. Seeds are roasted or boiled and consumed as food and the seed oil is used in rheumatism and also as krimighna by folk practitioners. The present work aimed in such less explored plants for its nutritional assessment and antioxidant study. Methods: The study conducted was to reveal preliminary nutritional value of seeds of G.ula in which total fat was done in Soxhlet apparatus, total protein taking Bovine serum as standard and total carbohydrates, taking glucose as standard. Antioxidant study was done comparing between aqueous extract of fresh nuts and roasted nuts of G. ula taking Vitamin C as standard by DPPH method. Results: Study revealed seeds of G.ula in which total fat was 2.15%, total protein was 1.26% and total carbohydrates was 0.057% and seeds proved to be nutritious. Antioxidant activity comparing between fresh and roasted seeds revealed that fresh seeds are having more antioxidant property. Conclusion: Folklore medicine has tremendous source of information regarding the utility of locally available plants for both as food and as medicines. Such plants have to be properly explored and scientifically documented before putting it into use. Keywords:Folklore, Gnetum ula, Kumti beejaView:PDF (679.44 KB)

Ecological value of global terrestrial plants

As a crucial primary producer of the earth, terrestrial plants play important functions in energy flow and biogeochemical cycles of the planet. However, their real wealth contributions to human society are not properly evaluated because of their widespread distribution and limitations in evaluation methods. This study used the emergy methodology to evaluate the ecological economic value of global terrestrial plants. Terrestrial plants were divided into three groups of bryophytes, gymnosperms and angiosperms for the emergy evaluation. The area of the system boundary for terrestrial plants was 13.5 E+9 ha. Total annual emergy use of the terrestrial plants was 10.29 E + 24 sej yr−1 which consisted of 9.19 E + 24 sej yr−1 by angiosperms, 1.00 E + 24 sej yr−1 used by gymnosperms, and 0.09 E + 24 sej yr−1 by bryophytes. The total emergy stored in the terrestrial plants was 648.50 E + 24 sej, with 550.28 E + 24 sej stored in angiosperms, 91.64 E + 24 sej in gymnosperms, and 6.58E+24 sej in bryophytes. The Unit Emergy Values (UEVs) of the Net Primary Production (NPP) of terrestrial plants was calculated as 183.31 E + 6 sej gC−1. For each plant group, UEVs were 189.00 E + 6 sej gC−1 for angiosperms, 145.54 E + 6 sej J − 1 for gymnosperms, and 159.63 E + 06 sej gC−1 for bryophytes. The emdollar values were calculated to determine approximate monetary values for production and storage of the terrestrial plants. The ecological values of the annual plant production were 5.14 trillion em$ for the all terrestrial plants with 4.59 trillion, 0.50 trillion, and 0.05 trillion em$ for angiosperm, gymnosperm, and bryophytes respectively. The ecological values stored in the plant biomasses were 324.25 trillion em$ for all the terrestrial plans, with 275.14 trillion, 45.82 trillion, and 3.29 trillion em$ for angiosperm, gymnosperm, and bryophytes respectively.

Ecology and evolution of cycad-feeding Lepidoptera.

Cycads are an ancient group of tropical gymnosperms that are toxic to most animals - including humans - though the larvae of many moths and butterflies (order: Lepidoptera) feed on cycads with apparent immunity. These insects belong to distinct lineages with varying degrees of specialisation and diverse feeding ecologies, presenting numerous opportunities for comparative studies of chemically mediated eco-evolutionary dynamics. This review presents the first evolutionary evaluation of cycad-feeding among Lepidoptera along with a comprehensive review of their ecology. Our analysis suggests that multiple lineages have independently colonised cycads from angiosperm hosts, yet only a few clades appear to have radiated following their transitions to cycads. Defensive traits are likely important for diversification, as many cycad specialists are warningly coloured and sequester cycad toxins. The butterfly family Lycaenidae appears to be particularly predisposed to cycad-feeding and several cycadivorous lycaenids are warningly coloured and chemically defended. Cycad-herbivore interactions provide a promising but underutilised study system for investigating plant-insect coevolution, convergent and divergent adaptations, and the multi-trophic significance of defensive traits; therefore the review ends by suggesting specific research gaps that would be fruitfully addressed in Lepidoptera and other cycad-feeding insects.

Revealing the diversity of amber source plants from the Early Cretaceous Crato Formation, Brazil

BackgroundAmber has been reported from the Early Cretaceous Crato Formation, as isolated clasts or within plant tissues. Undescribed cones of uncertain gymnosperm affinity have also been recovered with amber preserved in situ. Here, we provide multiple lines of evidence to determine the botanical affinity of this enigmatic, conspicuous cone type, and to better understand the diversity of amber-source plants present in the Crato Formation and beyond.ResultsA new taxon of amber-bearing pollen cone Araripestrobus resinosus gen. nov. et sp. nov. is described here from complete cones and characteristic disarticulated portions. The best-preserved cone portion has both in situ amber infilling the resin canals inside the preserved microsporophyll tissues and pollen of the Eucommiidites-type. This places this genus within the Erdtmanithecales, an incompletely known gymnosperm group from the Mesozoic.FTIR analysis of the in situ amber indicates a potential araucariacean conifer affinity, although affinity with cupressacean conifers cannot be definitely ruled out. Pyr-GC-MS analysis of the Araripestrobus resinosus gen. nov. et sp. nov. in situ fossil resin shows that it is a mature class Ib amber, thought to indicate affinities with araucariacean and cupressacean, but not pinaceous, conifers. This is the first confirmed occurrence of this class of amber in the Crato Formation flora and in South America, except for an archaeological sample from Laguna Guatavita, Colombia.ConclusionsThe combined results of the cones’ novel gross morphology and the analyses of the in situ amber and pollen clearly indicate that the new taxon of resinous gymnosperm pollen cones from the Crato Formation is affiliated with Erdtmanithecales. The cone morphology is very distinct from all known pollen cone types of this extinct plant group. We therefore assume that the plant group that produced Eucommiidites-type pollen is much more diverse in habits than previously thought. Moreover, the diversity of potential amber source plants from the Crato Formation is now expanded beyond the Araucariaceae and the Cheirolepidiaceae to include this member of the Erdtmanithecales. Despite dispersed Eucommiidites pollen being noted from the Crato Formation, this is the first time macrofossils of Erdtmanithecales have been recognized from the Early Cretaceous of South America.

Reinvestigating the fossil leaf Welwitschiophyllum brasiliense Dilcher et al. (2005), from the Lower Cretaceous Crato Formation of Brazil

The Lower Cretaceous Crato Formation of north-east Brazil yields a diverse plant assemblage. It has yielded many macrofossils thought to be related to the enigmatic gymnosperm group Gnetales, including the long leaf Welwitschiophyllum brasiliense Dilcher et al. 2005. This fossil plant is considered to be related to the extant gnetalean Welwitschia mirabilis Hooker 1863, despite lacking many gnetalean characteristics. Presently, this macrophyte fossil is known only from detached leaves and much anatomical information is currently unavailable. The reproductive structures assigned to the family Welwitschiaceae in the Crato Formation, as well as several key morphological features of the leaves are currently thought to relate fossil Welwitschiophyllum to extant Welwitschia. These leaf characters include: isobilateral leaf form, triangular elongated leaf shape with a wide base, longitudinal splitting from a frayed leaf apex, numerous parallel veins and possible thickening of the epidermis. However, several of these leaf characteristics also occur in many other macrophytes, perhaps as a result of convergence. Anatomical and morphological data described here from fossil Welwitschiophyllum leaves is compared with extant Welwitschia. Our results show that Welwitschiophyllum can only be placed tentatively in Gnetales, as many of the features we report are not diagnostic, and may have resulted from convergent evolution (e.g., gum). Fossils with better anatomical preservation and the reconstruction of the whole plant are really needed to better understand the affinities of Welwitschiophyllum.

Ecological Mechanism of Dinosaur Extinction

To analyze the reasons for the extinction of dinosaurs by applying the elimination methods, to exclude the factors that could not cause the worldwide extinction of the dinosaurs. At last obtain a conclusion that because the Ice Age had come on the Earth and caused the changing of climate that it had been becoming cold and arid from warmth and moist, and caused the phyto-group had been changing, which the Pteridophyte and gymnosperm groups fell off or died out, but the angiosperm groups had been developing and expanding. The characters of photosynthesis of producers of the biosphere had been becoming to the seasonal and regional from the perennial and global, the total of oxygen had reduced sharply in the atmosphere, the density of oxygen had declined, and finally affected the breath of dinosaurs, and led to the extinction of dinosaurs. And as the main producers of biosphere, the pteridophyte and gymnosperm groups had fallen off or died out were the mainly reasons for the creature’s extinction at the later of the Cretaceous period.

Ecological Mechanism of Dinosaur Extinction

To analyze the reasons for the extinction of dinosaurs by applying the elimination methods, to exclude the factors that could not cause the worldwide extinction of the dinosaurs. At last obtain a conclusion that because the Ice Age had come on the Earth and caused the changing of climate that it had been becoming cold and arid from warmth and moist, and caused the phyto-group had been changing, which the Pteridophyte and gymnosperm groups fell off or died out, but the angiosperm groups had been developing and expanding. The characters of photosynthesis of producers of the biosphere had been becoming to the seasonal and regional from the perennial and global, the total of oxygen had reduced sharply in the atmosphere, the density of oxygen had declined, and finally affected the breath of dinosaurs, and led to the extinction of dinosaurs. And as the main producers of biosphere, the pteridophyte and gymnosperm groups had fallen off or died out were the mainly reasons for the creature’s extinction at the later of the Cretaceous period.

High-throughput sequencing-based assembly of chloroplast genomes of five pine tree species

Pinus plants are the largest existing group of gymnosperms and one of the most highly differentiated taxa. Due to its huge ecological, economic, and scientific value, the genetic diversity and the relationship between the intraspecific evolution of Pinus plants have gained wide attention. In this study, the chloroplast genomes of several common pine trees in southwest and south China, including P. massoniana (masson pine), P. yunnanensis (yunnan pine), P. latteri (south asia pine), P. crassicorticea (la ya pine), and P. elliottii (slash pine), and entire cpDNA sequences were obtained. Characteristics including the structure, repeated sequence, and codon bias of the cpDNA for these five pine tree species were analyzed.

Refined Permian–Triassic floristic timeline reveals early collapse and delayed recovery of south polar terrestrial ecosystems

AbstractThe collapse of late Permian (Lopingian) Gondwanan floras, characterized by the extinction of glossopterid gymnosperms, heralded the end of one of the most enduring and extensive biomes in Earth’s history. The Sydney Basin, Australia, hosts a near-continuous, age-constrained succession of high southern paleolatitude (∼65–75°S) terrestrial strata spanning the end-Permian extinction (EPE) interval. Sedimentological, stable carbon isotopic, palynological, and macrofloral data were collected from two cored coal-exploration wells and correlated. Six palynostratigraphic zones, supported by ordination analyses, were identified within the uppermost Permian to Lower Triassic succession, corresponding to discrete vegetation stages before, during, and after the EPE interval. Collapse of the glossopterid biome marked the onset of the terrestrial EPE and may have significantly predated the marine mass extinctions and conodont-defined Permian–Triassic Boundary. Apart from extinction of the dominant Permian plant taxa, the EPE was characterized by a reduction in primary productivity, and the immediate aftermath was marked by high abundances of opportunistic fungi, algae, and ferns. This transition is coeval with the onset of a gradual global decrease in δ13Corg and the primary extrusive phase of Siberian Traps Large Igneous Province magmatism. The dominant gymnosperm groups of the Gondwanan Mesozoic (peltasperms, conifers, and corystosperms) all appeared soon after the collapse but remained rare throughout the immediate post-EPE succession. Faltering recovery was due to a succession of rapid and severe climatic stressors until at least the late Early Triassic. Immediately prior to the Smithian–Spathian boundary (ca. 249 Ma), indices of increased weathering, thick redbeds, and abundant pleuromeian lycophytes likely signify marked climate change and intensification of the Gondwanan monsoon climate system. This is the first record of the Smithian–Spathian floral overturn event in high southern latitudes.

Plastome Reduction in the Only Parasitic Gymnosperm Parasitaxus Is Due to Losses of Photosynthesis but Not Housekeeping Genes and Apparently Involves the Secondary Gain of a Large Inverted Repeat.

Plastid genomes (plastomes) of parasitic plants undergo dramatic reductions as the need for photosynthesis relaxes. Here, we report the plastome of the only known heterotrophic gymnosperm Parasitaxus usta (Podocarpaceae). With 68 unique genes, of which 33 encode proteins, 31 tRNAs, and four rRNAs in a plastome of 85.3-kb length, Parasitaxus has both the smallest and the functionally least capable plastid genome of gymnosperms. Although the heterotroph retains chlorophyll, all genes for photosynthesis are physically or functionally lost, making photosynthetic energy gain impossible. The pseudogenization of the three plastome-encoded light-independent chlorophyll biosynthesis genes chlB, chlL, and chlN implies that Parasitaxus relies on either only the light-dependent chlorophyll biosynthesis pathway or another regulation system. Nesting within a group of gymnosperms known for the absence of the large inverted repeat regions (IRs), another unusual feature of the Parasitaxus plastome is the existence of a 9,256-bp long IR. Its short length and a gene composition that completely differs from those of IR-containing gymnosperms together suggest a regain of this critical, plastome structure-stabilizing feature. In sum, our findings highlight the particular path of lifestyle-associated reductive plastome evolution, where structural features might provide additional cues of a continued selection for plastome maintenance.

The first record of Dicroidium from the Triassic palaeotropics based on dispersed cuticles from the Anisian Mukheiris Formation of Jordan

A new fossil meso-flora consisting of dispersed cuticles has been discovered within the Upper Member of the Middle Triassic (late Anisian) Mukheiris Formation at the eastern rim of the Dead Sea in Jordan. The assemblage consists of a number of different morpho-types of cuticles which can all be assigned to gymnosperms. Cuticles which can be identified as the corystospermalean taxon Dicroidium are fairly abundant and clearly dominate the assemblage, whereas cuticles assignable to other gymnosperms are rather rare. As so far all Triassic records of Dicroidium come from localities at palaeolatitudes above 35°S, these cuticles represent the first record of this genus within the Triassic palaeotropics. Our analysis of this meso-flora suggests that during the late Anisian, as in other regions worldwide, a gymnosperm component of the terrestrial vegetation on the Arabian Peninsula was present. Compared to the palynoflora, which yielded various types of conifer pollen, and pollen of other gymnosperm groups, as well as abundant spores of ferns and lycophytes, the meso-flora is so far lacking a number of plant groups which were present in the source vegetation. It is likely that the differences can be explained by taphonomical biases. The data from cuticles and palynology together prove that either regional terrestrial ecosystems had already recovered, at least to some extent, from the devastating effects of the end-Permian ecological crisis or that these effects were less devastating, at least with regard to vegetation, than assumed by previous studies.