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Spring leaf phenology is an important event for trees to determine carbon fixation during the growing season. However, less is understood about the intraspecific variation in spring leaf phenology and its relationship with the spring temperature requirements of conifers, which is problematic for accurately predicting the influence of spring climate warming on conifers. I monitored bud burst timing and the degree days required for bud burst for seedlings and large individuals of Abies sachalinensis (fir) and Larix kaempferi (larch) over two seasons in northern Japan. Contrary to my expectation, the degree days required for the bud burst of small individuals were similar to or larger than those of the large individuals for fir and larch. Consequently, the bud burst timing of small individuals was similar to or later than that of large individuals for fir and larch. Even when conifer species are in their early stage, the spring temperature requirement for bud burst is not necessarily less than that for large individuals, which is not the case for many broad-leaved species. These results indicate that for these two coniferous species, ontogenetic differences in temperature requirements are not necessary to be considered for the response of communities to spring climate change.

The type of Cycas debaoensis Y.C.Zhong & C.J.Chen (Y.C.Zhong 8762) consists of nine duplicates in PE. Our new investigation of the type collection suggests that the type includes at least two different gatherings which should be considered as syntypes. For nomenclatural purposes, we lectotypify the name Cycas debaoensis with the herbarium sheet PE00047578 and consider other duplicates in PE and GXMI as isolectotypes. The seeds in the capsule (Y.C.Zhong s.n. collected in Oct 1998) are considered as a syntype.

Reproductive phase change is well characterized in angiosperm model species, but less studied in gymnosperms. We utilize the early cone-setting acrocona mutant to study reproductive phase change in the conifer Picea abies (Norway spruce), a gymnosperm. The acrocona mutant frequently initiates cone-like structures, called transition shoots, in positions where wild-type P. abies always produces vegetative shoots. We collect acrocona and wild-type samples, and RNA-sequence their messenger RNA (mRNA) and microRNA (miRNA) fractions. We establish gene expression patterns and then use allele-specific transcript assembly to identify mutations in acrocona. We genotype a segregating population of inbred acrocona trees. A member of the SQUAMOSA BINDING PROTEIN-LIKE (SPL) gene family, PaSPL1, is active in reproductive meristems, whereas two putative negative regulators of PaSPL1, miRNA156 and the conifer specific miRNA529, are upregulated in vegetative and transition shoot meristems. We identify a mutation in a putative miRNA156/529 binding site of the acrocona PaSPL1 allele and show that the mutation renders the acrocona allele tolerant to these miRNAs. We show co-segregation between the early cone-setting phenotype and trees homozygous for the acrocona mutation. In conclusion, we demonstrate evolutionary conservation of the age-dependent flowering pathway and involvement of this pathway in regulating reproductive phase change in the conifer P. abies.

Torreya dapanshanica X.F.Jin, Y.F.Lu & Zi L.Chen, a new species endemic to central Zhejiang, East China, is described and illustrated. This new species is most similar to T. jiulongshanensis (Z.Y.Li, Z.C.Tang & N.Kang) C.C.Pan, J.L.Liu & X.F.Jin, but differs in having leaves with an acuminate apex (vs. leaves with an acute apex), broadly ovoid-globose or globose seeds (vs. obovoid to narrowly obovoid seeds), slightly emarginate at the apex and obtuse-rounded at the base (vs. both acute at the apex and base), testa with irregular shallow grooves (vs. testa smooth or sometimes slightly concave). The diagnostic characters are critically compared and an IUCN assessment for the risk to the new species is estimated.

PREMISE Wood density is a crucial plant functional trait related to plant strategies. Its ecological importance in small-stature growth forms (e.g., shrubs) has not been extensively examined. Given that hydraulic conduit dimensions vary positively with plant height and that there is a negative relationship between conduits' diameter and wood density, I hypothesize an also negative relationship between wood density and plant height. Knowing that bark and pith proportions are significant in small-diameter stems, I additionally disentangled the contribution of wood, bark and pith to stem density. METHODS I determined density in small-diameter stems across 153 species spanning all major angiosperm and gymnosperm orders by considering a diversity of growth forms (trees, treelets, shrubs, vines and hemiparasites). Stem cross-sections were dissected to consider density of wood with bark and pith (stem), wood with pith and without bark (barkless), wood with bark and no pith (pithless) and wood without bark and pith (wood only). Secondary growth was also measured. RESULTS Trees showed similar wood densities as non-self-supporting vines, and both of them showed significantly less dense wood than treelets, shrubs and hemiparasites. General comparisons resulted in that wood density was significantly denser than all other tissues' densities, and these differences did not depend on growth form. Wood density was significantly related to pith area proportions but not to growth rate or bark thickness proportion. CONCLUSIONS An implicit negative relationship between maximum plant height and stem density emerges as a property of plants likely linked to hydraulic conductive size. This article is protected by copyright. All rights reserved.

Palynological studies was carried out on GZ-1 well from the onshore western Niger Delta in order to recognized a new detected developments in the varieties of key pollen and spore taxa that have shorter and more distinguished interval zones to advance stratigraphical delineation. Palynological analysis was carried out using the conventional maceration technique for recovering acid insoluble organic-walled microfossils from sediments. The result yielded rich and diversified palynomorphs. The main assemblage were dominated by angiosperm pollen grain (dominant global flora from Late Cretaceous onwards) followed by pteridophytes/bryophyte spore. Dinoflagellate cysts, on the contrast, were less diverse while the Gymnosperm pollen were scarce. The identified palynomorph were used to establish seven main zones - AF1 Psilatricolporites crassus zone, AF2 Verrucatosporites usmensis zone, AF3 Triplochiton scleroxylon zone, AF4 Crassoretitriletes vanraadshooveni zone, AF5 Acrostichum aureum zone, AF6 Gemmatriporites ogwashiensis zone and AF7 Retitricolporites irregularis zone in this study. Established on quantitative events, the zones were also divided into seven subzones with some having finer subdivisions into (a) and (b) ranging in age from Early Oligocene to Early Miocene. Previous unfiled event trends of important indicator taxa of spores and pollen accredited to Pelliceria, Caesalapinoideae, Stenochlaena palustris, Polypodiaceae, Lygodium microphyllum, Polypodiaceae, Adiantaceae and Amanoa (Euphorbiaceae) have assisted improvement of formerly used palynological zonation schemes in the Niger Delta. It is anticipated that this quantitative zonation scheme erected, will help with imminent palynostratigraphical studies in the onshore Niger delta area.

Plants constitute 80% of the biomass on earth, and almost two-thirds of this biomass is found in wood. Wood formation is a carbon (C)-demanding process and relies on C transport from photosynthetic tissues. Thus, understanding the transport process is of major interest for understanding terrestrial biomass formation. Here, we review the molecules and mechanisms used to transport and allocate C in trees. Sucrose is the major form in which C is transported in plants, and it is found in the phloem sap of all tree species investigated so far. However, in several tree species, sucrose is accompanied by other molecules, notably polyols and the raffinose family of oligosaccharides. We describe the molecules that constitute each of these transport groups, and their distribution across different tree species. Furthermore, we detail the metabolic reactions for their synthesis, the mechanisms by which trees load and unload these compounds in and out of the vascular system, and how they are radially transported in the trunk and finally catabolized during wood formation. We also address a particular C recirculation process between phloem and xylem that occurs in trees during the annual cycle of growth and dormancy. A search of possible evolutionary drivers behind the diversity of C-carrying molecules in trees reveals no consistent differences in C transport mechanisms between angiosperm and gymnosperm trees. Furthermore, the distribution of C forms across species suggests that climate-related environmental factors will not explain the diversity of C transport forms. However, the consideration of C-transport mechanisms in relation to tree–rhizosphere coevolution deserves further attention. To conclude the review, we identify possible future lines of research in this field.

Welwitschia mirabilis, which is endemic to the Namib Desert, is the only living species within the family Welwitschiaceae. This species has an extremely long lifespan of up to 2,000 years and bears a single pair of opposite leaves that persist whilst alive. However, the underlying genetic mechanisms and evolution of the species remain poorly elucidated. Here, we report on a chromosome-level genome assembly for W. mirabilis, with a 6.30-Gb genome sequence and contig N50 of 27.50 Mb. In total, 39,019 protein-coding genes were predicted from the genome. Two brassinosteroid-related genes (BRI1 and CYCD3), key regulators of cell division and elongation, were strongly selected in W. mirabilis and may contribute to their long ever-growing leaves. Furthermore, 29 gene families in the mitogen-activated protein kinase signalling pathway showed significant expansion, which may contribute to the desert adaptations of the plant. Three positively selected genes (EHMT1, EIF4E, SOD2) may be involved in the mechanisms leading to long lifespan. Based on molecular clock dating and fossil calibrations, the divergence time of W. mirabilis and Gnetum montanum was estimated at ~123.5 million years ago. Reconstruction of population dynamics from genome data coincided well with the aridification of the Namib Desert. The genome sequence detailed in the current study provides insight into the evolution of W. mirabilis and should be an important resource for further study on gnetophyte and gymnosperm evolution.

The ancient gymnosperm genus Taxus is the exclusive source of the anticancer drug paclitaxel, yet no reference genome sequences are available for comprehensively elucidating the paclitaxel biosynthesis pathway. We have completed a chromosome-level genome of Taxus chinensis var. mairei with a total length of 10.23 gigabases. Taxus shared an ancestral whole-genome duplication with the coniferophyte lineage and underwent distinct transposon evolution. We discovered a unique physical and functional grouping of CYP725As (cytochrome P450) in the Taxus genome for paclitaxel biosynthesis. We also identified a gene cluster for taxadiene biosynthesis, which was formed mainly by gene duplications. This study will facilitate the elucidation of paclitaxel biosynthesis and unleash the biotechnological potential of Taxus.

Background and Aims The gymnosperm order Cycadales is pivotal to our understanding of seed-plant phylogeny because of its phylogenetic placement close to the root node of extant spermatophytes and its combination of both derived and plesiomorphic character states. Although widely considered a ‘living fossil’ group, extant cycads display a high degree of morphological and anatomical variation. We investigate stomatal development in Zamiaceae to evaluate variation within the order and homologies between cycads and other seed plants. Methods Leaflets of seven species across five genera representing all major clades of Zamiaceae were examined at various stages of development using light microscopy and confocal microscopy. Key Results All genera examined have lateral subsidiary cells of perigenous origin that differ from other pavement cells in mature leaflets and could have a role in stomatal physiology. Early epidermal patterning in a ‘quartet’ arrangement occurs in Ceratozamia, Zamia and Stangeria. Distal encircling cells, which are sclerified at maturity, are present in all genera except Bowenia, which shows relatively rapid elongation and differentiation of the pavement cells during leaflet development. Conclusions Stomatal structure and development in Zamiaceae highlights some traits that are plesiomorphic in seed plants, including the presence of perigenous encircling subsidiary cells, and reveals a clear difference between the developmental trajectories of cycads and Bennettitales. Our study also shows an unexpected degree of variation among subclades in the family, potentially linked to differences in leaflet development and suggesting convergent evolution in cycads.

The mechanisms regulating spring phenology have been extensively studied in angiosperm species. However, given that gymnosperms and angiosperms diverged 300 million years ago, phenology may be triggered by different cues in gymnosperm species. The regulatory mechanisms of phenology in subtropical regions remain largely unknown. In combination, it remains untested whether subtropical gymnosperm species have chilling requirements and are photosensitive. We conducted a climate chamber experiment with three chilling and three photoperiod treatments to investigate budburst during an 8-week forcing period. We tested whether budburst of eight gymnosperms species (Cryptomeria japonica, Cunninghamia lanceolata, Cupressus funebris, Ginkgo biloba, Metasequoia glyptostroboides, Pinus massoniana, Pseudolarix amabilis and Podocarpus macrophyllus) was photoperiod sensitive or has strong chilling requirements and whether photoperiod or chilling was more important for advancing budburst. Chilling advanced budburst and increased the percentage of budburst for gymnosperm species. Gymnosperm species required moderate chilling days to advance budburst. Interestingly, the forcing requirement for gymnosperm species was higher than that for angiosperms in the same forest, suggesting that gymnosperms may need more cumulative forcing to initiate budburst than do angiosperms. Compared with temperate gymnosperm species in Germany (194–600 °C days), the subtropical species studied here had a much higher forcing requirement (814–1150 °C days). The effects of photoperiod were minor, suggesting that chilling outweighs photoperiod in advancing budburst of gymnosperm species in this subtropical region. These results reveal that increased winter temperatures with continued global warming may impact not only angiosperms but also gymnosperms, leading to their delayed spring budburst.

Premise of research. In this contribution, the spectroscopic characterization of gymnosperm fossil remains belonging to Pteridospermophyta, Cycadophyta, Ginkgophyta, and Coniferophyta collected fro...

Gymnosperms are a unique lineage of plants that currently lack a high-quality reference genome due to their large genome size and high repetitive sequence content. Here, we report a nearly complete genome assembly for Ginkgo biloba with a genome size of 9.87 Gb, an N50 contig size of 1.58 Mb and an N50 scaffold size of 775 Mb. We were able to accurately annotate 27,832 protein-coding genes in total, superseding the inaccurate annotation of 41,840 genes in a previous draft genome assembly. We found that expansion of the G. biloba genome, accompanied by the notable extension of introns, was mainly caused by the insertion of long terminal repeats rather than the recent occurrence of whole-genome duplication events, in contrast to the findings of a previous report. We also identified candidate genes in the central pair, intraflagellar transport and dynein protein families that are associated with the formation of the spermatophore flagellum, which has been lost in all seed plants except ginkgo and cycads. The newly obtained Ginkgo genome provides new insights into the evolution of the gymnosperm genome. Analyses on a newly assembled, nearly complete genome of Ginkgo biloba revealed the cause of genome expansion and candidate genes associated with the formation of spermatophore flagellum in ginkgo, advancing our understanding about gymnosperm evolution.

Background and aims The ovule is a synapomorphy of all seed plants (gymnosperms and angiosperms); however, there are some striking differences in ovules among the major seed plant lineages, such as the number of integuments or the orientation of the ovule. The genetics involved in ovule development have been well studied in the model species Arabidopsis thaliana, which has two integuments and anatropous orientation. This study is approached from what is known in arabidopsis, focusing on the expression patterns of homologues of four genes known to be key for the proper development of the integuments in arabidopsis: AINTEGUMENTA (ANT), BELL1, (BEL1), KANADIs (KANs) and UNICORN (UCN). Methods We used histology to describe the morphoanatomical development from ovules to seeds in Gnetum gnemon. We carried out spatiotemporal expression analyses in G. gnemon, a gymnosperm, which has a unique ovule morphology with an integument covering the nucellus, two additional envelopes where the outermost becomes fleshy as the seed matures, and an orthotropous orientation. Key Results Our anatomical and developmental descriptions provide a framework for expression analyses in the ovule of G. gnemon. Our expression results show that although ANT, KAN and UCN homologues are expressed in the inner integument, their spatiotemporal patterns differ from those found in angiosperms. Furthermore, all homologues studied here are expressed in the nucellus, revealing major differences in seed plants. Finally, no expression of the studied homologues was detected in the outer envelopes. Conclusions Altogether, these analyses provide significant comparative data that allows us to better understand the functional evolution of these gene lineages, providing a compelling framework for evolutionary and developmental studies of seeds. Our findings suggest that these genes were most likely recruited from the sporangium development network and became restricted to the integuments of angiosperm ovules.

The first Jurassic palynofloral assemblage from Japan is reported from the Oxfordian Tochikubo Formation of the Soma-Nakamura Group, Fukushima Prefecture. Palynomorphs are quite diversified, with 32 genera and 41 species of lycopod and fern spores, gymnosperm pollen and freshwater algae. The composition of the assemblage is consistent with the Oxfordian age of this nonmarine formation and confirms a fluvio-lacustrine paleoenvironment, further detailing the paleovegetation reconstructed from macrofloral remains. Previous palynofloral reports of eastern Asia are reviewed and indicate that northeast Japan shares most similarities with coeval paleofloras of southeastern Russia. Consequences for paleofloristic provincialism and climates of the region during the Late Jurassic are discussed.

Gymnosperm taxa are incredibly diverse in many traits, including taxa with evergreen or deciduous leaves; broad, compound, needle-like or scale-like leaves; trees, shrubs, and lianas; and taxa with seed cones that range from fleshy to woody. Although less appreciated, xylem conduits are also diverse in structure among extant gymnosperm taxa. Within the xylem of gymnosperms, axial transport occurs predominantly via tracheids, although 10-40% of gymnosperm taxa, particularly within the Gnetophyta and Cycadophyta, also contain vessels. Gymnosperm taxa vary greatly in their inter-conduit pit structure, with different types of pit membranes and pitting arrangements. While some taxa display torus-margo bordered pits (60%), many others do not contain tori (40%), and at least some taxa without tori occur within each of the four extant phyla (Coniferophyta, Cycadophyta, Ginkgophyta, and Gnetophyta). Pit membrane types vary within families but appear relatively conserved within genera. Woody species with torus-bearing pit membranes occur in colder environments (lower mean annual temperature) compared to those without tori; but occurrence does not differ with mean annual precipitation. Detailed descriptions of pit membrane types are lacking for many species and genera, indicating a need for increased anatomical study. Increased knowledge of these traits could provide a unique experimental context in which to study the evolution of conduit networks, the hydraulic implications of conduit and pit structure, and the diverse structural and functional strategies utilized by gymnosperms. There are myriad potential study questions and research opportunities within this unique and diverse group of plants.

Due to its ancient origin in the Permian and the high proportion of beetle-pollinated taxa within ancestral magnoliid lineages, it has been hypothesized that beetles were among the first floral visitors of the proto-angiosperms on Earth. Thus, beetle-pollinated flowers have become important model systems essential for the study of the origin and evolution of angiosperms. Under an evolutionary perspective, in this review we synthesize what is currently known about beetles as floral visitors in the family Magnoliaceae, one of the earliest extant groups of flowering plants. Nitidulidae and Scarabaeidae are the two most common groups of beetles reported in the literature as floral visitors to Magnoliaceae; however, the evidence indicates that most modern families of beetles including all the families with known taxa associated with Magnoliaceae had already originated when the latter first appeared by the end of the early Cretaceous. Hence, Magnoliaceae could have represented a newly opened ecological niche that beetles gradually colonized and exploited, possibly shifting from gymnosperm hosts. By feeding, mating and sheltering in their flower structures, beetles have played a major role in shaping the floral biology and morphology of Magnoliaceae. Protogyny, thermogenesis, floral odors and floral movements are traits that could have evolved in response to selection pressures imposed by beetles. Further studies should assess the possible role of anthophagous scarabs (subfamilies Cetoniinae, Melolonthinae, Dynastinae and Rutelinae) in the diversification of Magnoliaceae, since this event broadly coincides with the origin of those groups of beetles in the Eocene, some of which exhibit very close associations with several Magnoliaceae species.

Varied floristic works relevant to Kashmir Himalaya were thoroughly examined to compile taxonomic contributions of various taxonomists viz. a viz. diversity in gymnosperms of this region. Extensive field surveys and standard taxonomic methods were used to locate, collect, identify and prepare an updated list of the target group. A total of 25 species of gymnosperms belonging to 13 genera in 6 families and 4 orders have been documented from the Kashmir Himalaya. Wild gymnosperms are represented by 11 species with conifers forming the most dominant group. Among families, Pinaceae is highest represented with 6 species, while Taxaceae is least represented. Cultivated gymnosperms exceed wild growing species, and Cupressaceae is most dominant with 9 species whereas Ginkgoaceae is least represented. Out 25 species 19 (7 wild + 12 cultivated) are trees, 5 (3 wild + 2 cultivated) are shrubs and only 1 is sub-shrub.

The DELAY OF GERMINATION1 (DOG1) family genes (DFGs) in Arabidopsis thaliana are involved in seed dormancy, reserve accumulation, and desiccation tolerance. Decoding the molecular evolution of DFGs is key to understanding how these seed programs evolved. This article demonstrates that DFGs have diverged in the four lineages DOG1, DOG1-LIKE4 (DOGL4), DOGL5 and DOGL6, whereas DOGL1, DOGL2 and DOGL3 arose separately within the DOG1 lineage. The systematic DFG nomenclature proposed in this article addresses the current issues of inconsistent DFG annotation and highlights DFG genomic synteny in angiosperms. DFG pseudogenes, or collapsed coding sequences, hidden in the genomes of early-diverging angiosperms are documented here. They suggest ancient birth and loss of DFGs over the course of angiosperm evolution. The proposed models suggest that the origin of DFG diversification dates back to the most recent common ancestor of living angiosperms. The presence of a single form of DFG in nonflowering plants is discussed. Phylogenetic analysis of gymnosperm, lycophyte, and liverwort DFGs and similar genes found in mosses and algae suggests that DFGs diverged from the TGACG motif-binding transcription factor genes before the divergence of the bryophyte lineage.

Hydrasperman pteridosperms (seed ferns) were widespread and diverse in Carboniferous equatorial wetlands of Euramerica, and although present in Permian equatorial wetlands in Cathaysia, little is k...

The giant sequoia (Sequoiadendron giganteum) of California are massive, long-lived trees that grow along the U.S. Sierra Nevada mountains. Genomic data are limited in giant sequoia and producing a reference genome sequence has been an important goal to allow marker development for restoration and management. Using deep-coverage Illumina and Oxford Nanopore sequencing, combined with Dovetail chromosome conformation capture libraries, the genome was assembled into eleven chromosome-scale scaffolds containing 8.125 Gbp of sequence. Iso-Seq transcripts, assembled from three distinct tissues, was used as evidence to annotate a total of 41,632 protein-coding genes. The genome was found to contain, distributed unevenly across all 11 chromosomes and in 63 orthogroups, over 900 complete or partial predicted NLR genes, of which 375 are supported by annotation derived from protein evidence and gene modeling. This giant sequoia reference genome sequence represents the first genome sequenced in the Cupressaceae family, and lays a foundation for using genomic tools to aid in giant sequoia conservation and management.

The genusOsmundaL. contains approximately 10 extant species widely distributed in tropical and temperate regions, with the greatest concentration of species in East and Southeast Asia.Osmundais characterized by dimorphic or commonly hemidimorphic fronds with dimorphic pinnae. Its geological history has been traced back to the Triassic. Most records of the genus are based on rhizomes and rarely on pinnae bearing sporangia and spores. Here, we describe fossil pinnae, sporangia, and spores ofOsmunda lignitum(Giebel) Stur recovered from the middle Eocene of the Changchang Formation in the Changchang Basin, Hainan Island and the Youganwo Formation in the Maoming Basin, Guangdong, South China. The fossils closely resemble the extantOsmunda banksiifolia(C. Presl) Kuhn of the subgenusPlenasiumon the basis of their morphological and anatomical structures. The present occurrence ofO. lignitumindicates subg.Plenasiumflourished and extended from the high latitude regions such as Northeast China to the low latitude areas of South China during the middle Eocene. Large numbers of specimens described here also indicate thatOsmundawas the dominant understory fern element beneath mixed evergreen broad-leaf angiosperm and gymnosperm forests living in a warm and humid environment.

The gymnosperms are a taxon of plants that release large amounts of pollen. Some genera of this group are specifically studied because their pollen is known to be the cause of respiratory diseases....

Premise of research. Climbing plants are important components of modern-day tropical forests and primarily comprise angiosperms, but in Paleozoic tropical forests, pteridosperms were the dominant c...

The pollination drop (PD), also known as an ovular secretion, is a critical feature of most wind-pollinated gymnosperms and function as an essential component of pollination systems. However, the metabolome and small RNAs of gymnosperm PDs are largely unknown. We employed gas chromatography–mass spectrometry to identify a total of 101 metabolites in Ginkgo biloba L. PDs. The most abundant metabolites were sugars (45.70%), followed by organic acids (15.94%) and alcohols (15.39%) involved in carbohydrate metabolism, glycine, serine and threonine metabolism. Through pollen culture of the PDs, we further demonstrated that the metabolic components of PDs are indispensable for pollen germination and growth; in particular, organic acids and fatty acids play defensive roles against microbial activity. In addition, we successfully constructed a small RNA library and detected 45 known and 550 novel miRNAs in G. biloba PDs. Interestingly, in a comparative analysis of miRNA expression between PDs and ovules, we found that most of the known miRNAs identified in PDs were also expressed in the ovules, implying that miRNAs in PDs may originate from ovules. Further, combining with potential target prediction, degradome validation and transcriptome sequencing, we identified that the interactions of several known miRNAs and their targets in PDs are involved in carbohydrate metabolism, hormone signaling and defense response pathways, consistent with the metabolomics results. Our results broaden the knowledge of metabolite profiling and potential functional roles in gymnosperm PDs and provide the first evidence of extracellular miRNA functions in ovular secretions from gymnosperms.

Continuing the study of petrified gymnosperm trunks recovered from the Pedra de Fogo Formation, we identify here two new taxa from the Permian deposits of the Parnaiba Basin, northeastern Brazil. One taxon is an endemic form named Ductolobatopitys mussae Conceicao, Neregato et Iannuzzi, nov. gen., nov. sp., characterized by solenoid, lobed and non-septate heterocellular pith, cauline bundles with endarch maturation, and secondary xylem with araucarian radial pitting on the tracheid walls. The other form is assigned to the genus Kaokoxylon, which has been recorded from most of Gondwana, including the Parnaiba Basin, but is recorded for the first time from the Pedra de Fogo Formation with the new species Kaokoxylon brasiliensis. It is characterized by solid, non-septate heterocellular pith with sclerenchyma cells, endarch cauline bundles, and uni-to triseriate radial pitting on the walls of the tracheids. The sedimentological interpretations of the outcrops where the fossils were collected indicate that these plants lived on the shores of large continental lakes, with relatively high humidity but possibly periods of drought. These inferences are supported by growth interruptions in the secondary xylem, the presence of calamitalean and tree-fern stems, and microbialites that crop in the same area. These new finds not only increase the known diversity of the flora in the Pedra de Fogo Formation, but also provide more accurate information for understanding the floristic elements that formed the subtropical flora during the Cisuralian in this basin in Western Gondwana.

Plant mitochondrial genomes vary widely in size. Although many plant mitochondrial genomes have been sequenced and assembled, the vast majority are of angiosperms, and few are of gymnosperms. Most plant mitochondrial genomes are smaller than a megabase, with a few notable exceptions. We have sequenced and assembled the complete 5.5-Mb mitochondrial genome of Sitka spruce (Picea sitchensis), to date, one of the largest mitochondrial genomes of a gymnosperm. We sequenced the whole genome using Oxford Nanopore MinION, and then identified contigs of mitochondrial origin assembled from these long reads based on sequence homology to the white spruce mitochondrial genome. The assembly graph shows a multipartite genome structure, composed of one smaller 168-kb circular segment of DNA, and a larger 5.4-Mb single component with a branching structure. The assembly graph gives insight into a putative complex physical genome structure, and its branching points may represent active sites of recombination.

Curvularia includes plant pathogenic species with a worldwide distribution and a wide host range, particularly cereals and grass (Poaceae). Chinese fir (Cunninghamia lanceolata) is an important afforestation tree species in southern China, with a high economic value. Leaf blight disease on Chinese fir was discovered in Hunan and Zhejiang, China, and two fungal species were found to be associated with the symptoms. Using morphological and phylogenetic approaches, they were identified as Curvularia spicifera and Curvularia muehlenbeckiae. They were determined to be the pathogens by fulfilling Koch's postulates. Both showed a pathogenicity on Citrus reticulata and Citrus tangerina, which have a similar geographic distribution to Chinese fir. The similar geographic distribution of these hosts may increase the risk of disease. Based on a literature review, leaf blight caused by C. spicifera and C. muehlenbeckiae is recorded here on a gymnosperm for the first time.

Since historical buildings are living mirrors of the past, it is very important to preserve and transfer them to future generations. In this study, plants growing on the walls of Alanya Castle were identified and the damages that these plants gave to the historical construction and the precautions to be taken to prevent these damages were emphasized. A total of 94 plant taxa, including five pteridophytes, one gymnosperm and 88 angiosperms, belonging to 35 families were identified on the walls of Alanya Castle. Conyza canadensis, Inula heterolepis, Phagnalon graecum, Arabis verna, Mercurialis annua, Fumaria parviflora, Cymbalaria microcalyx, Galium canum subsp. antalyense, Parietaria judaica, Hyoscyamus aureus, Poa bulbosa were the dominant plant species of Alanya Castle walls. Possible seed dispersion of these plants on the castle walls and the methods for controlling them are discussed in detail. We conclude that the most effective method of combating plants that grow naturally on historical buildings and give damage to these buildings is mechanical excavation.

Background Plant dispersal units, or diaspores, allow the colonization of new environments expanding geographic range and promoting gene flow. Two broad categories of diaspores found in seed plants are dry and fleshy, associated with abiotic and biotic dispersal agents, respectively. Anatomy and developmental genetics of fleshy angiosperm fruits is advanced in contrast to the knowledge gap for analogous fleshy structures in gymnosperm diaspores. Improved understanding of the structural basis of modified accessory organs that aid in seed dispersal will enable future work on the underlying genetics, contributing to hypotheses on the origin of angiosperm fruits. To generate a structural framework for the development and evolution of gymnosperm fleshy diaspores, we studied the anatomy and histochemistry of Ephedra (Gnetales) seed cone bracts, the modified leaves surrounding the reproductive organs. We took an ontogenetic approach, comparing and contrasting the anatomy and histology of fleshy and papery-winged seed cone bracts, and their respective pollen cone bracts and leaves in four species from the South American clade. Results Seed bract fleshiness in Ephedra derives from mucilage accumulated in chlorenchyma cells, also found in the reduced young leaves before they reach their mature, dry stage. Cellulosic fibers, an infrequent cell type in gymnosperms, were found in Ephedra, where they presumably function as a source of supplementary apoplastic water in fleshy seed cone bracts. Papery-winged bract development more closely resembles that of leaves, with chlorenchyma mucilage cells turning into tanniniferous cells early on, and hyaline margins further extending into “wings”. Conclusions We propose an evolutionary developmental model whereby fleshy and papery-winged bracts develop from an early-stage anatomy shared with leaves that differs at the pollination stage. The ancestral fleshy bract state may represent a novel differentiation program built upon young leaf anatomy, while the derived dry, papery-winged state is likely built upon an existing differentiation pattern found in mature vegetative leaves. This model for the evolution of cone bract morphology in South American Ephedra hence involves a novel differentiation program repurposed from leaves combined with changes in the timing of leaf differentiation, or heterochrony, that can further be tested in other gymnosperms with fleshy diaspores.

For most of the Phanerozoic Eon, Earth’s woody vegetation has been dominated by C3 plants - predominantly gymnosperms - with angiosperms only emerging as the dominant plant group as CO2 declined during the Cenozoic (66 Ma onward). At present, differences in carbon isotope discrimination ( Δ 13 C ) between angiosperm and gymnosperm plants are relatively small (2–3 ‰), but an increasing body of evidence points to larger differences across geological times (up to 6–7 ‰), potentially associated with varying environmental conditions and atmospheres (i.e. concentrations of atmospheric carbon dioxide, [CO2], and oxygen, [O2] could have ranged from ∼ 180 to 1100 ppm, and ∼ 15 to 25%, respectively, across the past 250 Ma). Yet, differences in Δ 13 C between the two plant groups, and their potential link to climatic and environmental changes, have not yet been fully explored and understood. Here, we combine a comprehensive ab initio model of discrimination, with a recent model of plant eco-physiology based on least-cost optimality theory, to show how differences in Δ 13 C between angiosperms and gymnosperms arise. We train the comprehensive model using a very large ( n > 7000 ) database of leaf and tree ring data spanning the past 110 years. We find that averaged differences in Δ 13 C between angiosperm and gymnosperms decrease modestly with atmospheric [O2]:[CO2] ratios, and increase strongly with vapor pressure deficit (D). These relationships can be explained by three key physiological differences: (1) the ratio of cost factors for transpiration to carboxylation (higher in angiosperms); (2) the ratio of mesophyll to stomatal conductances of CO2 (lower in gymnosperms); and (3) differences in photorespiration. In particular, the amount of CO2 released from photorespiration per oxygenation reaction, λ , is generally lower in gymnosperms than in angiosperms. As a result of these factors, Δ 13 C is more sensitive to [CO2] in angiosperms, and to D in gymnosperms. We propose a simplified empirical model to account for this behaviour, and test it against isotopic data from leaves, tree rings and previously-published plant chamber experiments, along with geological data from the Cenozoic. Overall, these data agree with our model over a range of [O2]:[CO2] ratios from 100 to 650 mol mol−1 (equivalent to a CO2 range around 323–2100 ppm at 21% O2), and D levels between 0.45 and 1.1 kPa (R2 = 0.51, RMSE = 1.49 ‰). Our simplified empirical model offers a new explanation for secular trends in the geological record, and suggests a way forward to improve paleo-[CO2] proxies based on terrestrial discrimination models by incorporating the effects of [O2], phylogeny, and photorespiration. Lastly, the framework predicts that the average difference in Δ 13 C between woody C3 plant groups will increase in the future if both [CO2] and global D continue to rise as suggested by projections.

Background R2R3-MYB is a class of transcription factor crucial in regulating secondary cell wall development during wood formation. The regulation of wood formation in gymnosperm has been understudied due to its large genome size. Using Single-Molecule Real-Time sequencing, we obtained full-length transcriptomic libraries from the developmental stem of Cunninghamia lanceolata, a perennial conifer known as Chinese fir. The R2R3-MYB of C. lanceolata (hereafter named as ClMYB) associated with secondary wall development were identified based on phylogenetic analysis, expression studies and functional study on transgenic line. Results The evolutionary relationship of 52 ClMYBs with those from Arabidopsis thaliana, Eucalyptus grandis, Populus trichocarpa, Oryza sativa, two gymnosperm species, Pinus taeda, and Picea glauca were established by neighbour-joining phylogenetic analysis. A large number of ClMYBs resided in the woody-expanded subgroups that predominated with the members from woody dicots. In contrast, the woody-preferential subgroup strictly carrying the members of woody dicots contained only one candidate. The results suggest that the woody-expanded subgroup emerges before the gymnosperm/angiosperm split, while most of the woody-preferential subgroups are likely lineage-specific to woody dicots. Nine candidates shared the same subgroups with the A. thaliana orthologs, with known function in regulating secondary wall development. Gene expression analysis inferred that ClMYB1/2/3/4/5/26/27/49/51 might participate in secondary wall development, among which ClMYB1/2/5/26/27/49 were significantly upregulated in the highly lignified compression wood region, reinforcing their regulatory role associated with secondary wall development. ClMYB1 was experimentally proven a transcriptional activator that localised in the nucleus. The overexpression of ClMYB1 in Nicotiana benthamiana resulted in an increased lignin deposition in the stems. The members of subgroup S4, ClMYB3/4/5 shared the ERF-associated amphiphilic repression motif with AtMYB4, which is known to repress the metabolism of phenylpropanoid derived compounds. They also carried a core motif specific to gymnosperm lineage, suggesting divergence of the regulatory process compared to the angiosperms. Conclusions This work will enrich the collection of full-length gymnosperm-specific R2R3-MYBs related to stem development and contribute to understanding their evolutionary relationship with angiosperm species.

The discovery of telomeric repeats in interstitial regions of plant chromosomes (ITRs) through molecular cytogenetic techniques was achieved several decades ago. However, the information is scattered and has not been critically evaluated from an evolutionary perspective. Based on the analysis of currently available data, it is shown that ITRs are widespread in major evolutionary lineages sampled. However, their presence has been detected in only 45.6% of the analysed families, 26.7% of the sampled genera, and in 23.8% of the studied species. The number of ITR sites greatly varies among congeneric species and higher taxonomic units, and range from one to 72 signals. ITR signals mostly occurs as homozygous loci in most species, however, odd numbers of ITR sites reflecting a hemizygous state have been reported in both gymnosperm and angiosperm groups. Overall, the presence of ITRs appears to be poor predictors of phylogenetic and taxonomic relatedness at most hierarchical levels. The presence of ITRs and the number of sites are not significantly associated to the number of chromosomes. The longitudinal distribution of ITR sites along the chromosome arms indicates that more than half of the ITR presences are between proximal and terminal locations (49.5%), followed by proximal (29.0%) and centromeric (21.5%) arm regions. Intraspecific variation concerning ITR site number, chromosomal locations, and the differential presence on homologous chromosome pairs has been reported in unrelated groups, even at the population level. This hypervariability and dynamism may have likely been overlooked in many lineages due to the very low sample sizes often used in cytogenetic studies.

Background Chloroplast transfer RNAs (tRNAs) can participate in various vital processes. Gymnosperms have important ecological and economic value, and they are the dominant species in forest ecosystems in the Northern Hemisphere. However, the evolution and structural changes in chloroplast tRNAs in gymnosperms remain largely unclear. Results In this study, we determined the nucleotide evolution, phylogenetic relationships, and structural variations in 1779 chloroplast tRNAs in gymnosperms. The numbers and types of tRNA genes present in the chloroplast genomes of different gymnosperms did not differ greatly, where the average number of tRNAs was 33 and the frequencies of occurrence for various types of tRNAs were generally consistent. Nearly half of the anticodons were absent. Molecular sequence variation analysis identified the conserved secondary structures of tRNAs. About a quarter of the tRNA genes were found to contain precoded 3′ CCA tails. A few tRNAs have undergone novel structural changes that are closely related to their minimum free energy, and these structural changes affect the stability of the tRNAs. Phylogenetic analysis showed that tRNAs have evolved from multiple common ancestors. The transition rate was higher than the transversion rate in gymnosperm chloroplast tRNAs. More loss events than duplication events have occurred in gymnosperm chloroplast tRNAs during their evolutionary process. Conclusions These findings provide novel insights into the molecular evolution and biological characteristics of chloroplast tRNAs in gymnosperms.

Sequencing, assembly, and annotation of the 26.5 Gbp hexaploid genome of coast redwood (Sequoia sempervirens) was completed leading toward discovery of genes related to climate adaptation and investigation of the origin of the hexaploid genome. Deep-coverage short-read Illumina sequencing data from haploid tissue from a single seed were combined with long-read Oxford Nanopore Technologies sequencing data from diploid needle tissue to create an initial assembly, which was then scaffolded using proximity ligation data to produce a highly contiguous final assembly, SESE 2.1, with a scaffold N50 size of 44.9 Mbp. The assembly included several scaffolds that span entire chromosome arms, confirmed by the presence of telomere and centromere sequences on the ends of the scaffolds. The structural annotation produced 118,906 genes with 113 containing introns that exceed 500 Kbp in length and one reaching 2 Mb. Nearly 19 Gbp of the genome represented repetitive content with the vast majority characterized as long terminal repeats, with a 2.9:1 ratio of Copia to Gypsy elements that may aid in gene expression control. Comparison of coast redwood to other conifers revealed species-specific expansions for a plethora of abiotic and biotic stress response genes, including those involved in fungal disease resistance, detoxification, and physical injury/structural remodeling and others supporting flavonoid biosynthesis. Analysis of multiple genes that exist in triplicate in coast redwood but only once in its diploid relative, giant sequoia, supports a previous hypothesis that the hexaploidy is the result of autopolyploidy rather than any hybridizations with separate but closely related conifer species.

Premise of study“El Chango” is a recently discovered quarry that contains extremely well preserved fossils. The Cenomanian age of the locality corresponds to a time when the global flora was transitioning from gymnosperm- to angiosperm-dominated, yet conifers predominate in this locality. These fossils thus provide a rare opportunity to understand the replacement of conifers by angiosperms as the dominant group of plants.MethodsWe collected material from El Chango in annual expeditions (2010 to 2014). We selected the three most abundant and best preserved conifer morphotypes and conducted a total-evidence (i.e.,, including molecular and morphological data) phylogenetic analysis of a sample of 72 extant conifer species plus the three fossils. We use these results to inform our taxonomic decisions.ResultsWe obtained four equally most-parsimonious trees (consistency index = 44.1%, retention index = 78.8%). Despite ambiguous relationships among some extant taxa, the three fossil conifers had the same phylogenetic position in all four most-parsimonious trees; we describe these species as new:Sequoiadendron helicalancifoliumsp. nov. (Cupressaceae), andMicrocachrys rhomboideasp. nov. andDacrydium bifoliosussp. nov (Podocarpaceae). The ecosystem is interpreted as a coastal humid mixed forest.ConclusionsOur findings contribute to the understanding of Cenomanian equatorial regions, and support the hypothesis of a geographically and ecologically structured “rise of angiosperms”, with conifers remaining dominant in brackish-water and angiosperms becoming dominant in freshwater-ecosystems. These fossils fill in gaps in the evolutionary history of lineages likeMicrocachrys, which we demonstrate occurred in the Northern hemisphere before becoming restricted to its current range (Tasmania).

Rubisco specificity factor (Sc/o), a measure of the relative capacities of an enzyme to catalyze carboxylation and oxygenation of ribulose-1,5-bisphosphate, determines the extent of photosynthetic CO2 assimilation and photorespiratory CO2 release. The current model of C3 photosynthesis, the Farquhar–von Caemmerer–Berry (FvCB) model, requires a species-specific Sc/o. However, Sc/o values have never been reported in conifers, likely because in vitro kinetic analysis of conifer Rubisco presents difficulties. To estimate the Sc/o of conifers and compare it with angiosperm Sc/o, we measured changes in leaf CO2 compensation points (Γ) in response to O2 partial pressure for a variety of leaves, with different rates of day respiration (Rday) and maximum Rubisco carboxylation (Vcmax) in gymnosperms (Ginkgo biloba), conifers (Metasequoia glyptostroboides and Cryptomeria japonica), and angiosperms (Nicotiana tabacum and Phaseolus vulgaris). As predicted by the FvCB model, the slope of a linear function of Γ vs O2 partial pressure, d, increased alongside increasing Rday/Vcmax. The Sc/o was obtainable from this relationship between d and Rday/Vcmax, because the d values at Rday/Vcmax = 0 corresponded to α/Sc/o, where α was the photorespiratory CO2 release rate per Rubisco oxygenation rate (generally assumed to be 0.5). The calculated Sc/o values of N. tabacum and P. vulgaris exhibited good agreement with those reported by in vitro studies. The Sc/o values of both conifers were similar to those of the two angiosperm species. In contrast, the Sc/o value of G. biloba was significantly lower than those of the other four studied species. These results suggest that our new method for Sc/o estimation is applicable to C3 plants, including those for which in vitro kinetic analysis is difficult. Furthermore, results also suggest that conifer Sc/o does not differ significantly from that of C3 angiosperms, assuming α remains unchanged.

Direct fossil evidence for Mesozoic flower pollination is scarce. Umenocoleoid micro-cockroaches Lepidopterix vegrandis gen. et sp. n. (Lebanese amber) and Antophiloblatta hispida gen. et sp. n. (Myanmar amber) possess size, form, complex coloration pattern and surface structure, cryptic with potentially entomophilous angiosperms Tropidogyne pentaptera Poinar, 2017 and Antiquifloris latifibris Poinar et Buckley, 2016 flower petals and sepals. Putative pollen grains attached to the latter adult indicates pollination, while reduced mouthparts suggest fluid nectar feeding. Spongistoma angusta gen. et sp. n. (Myanmar amber) has a narrow body and mandibles nearly entirely reduced with a unique “proboscis” forming sponging/ sucking mouthparts. In addition putative Classopolis Pflug, 1953 gymnosperm pollen is attached to adults and immature individuals of Vzrkadlenie miso gen. et sp. n. (Myanmar amber). Together with possible angiosperm pollination by Formicamendax vrsanskyi Hinkelman, 2019 and cycas pollination by immature individuals of alienopterid larvae, the evidence for early cockroach pollination is now substantial. Additionally unique is the forewing surface of L. vegrandis with photonic crystal structures within the scales.

Plants generally use soil inorganic nitrogen, ammonium (NH₄⁺-N), and nitrate (NO₃⁻–N) as sources of nitrogen, an essential nutrient. The assimilation processes after uptake differ considerably from ammonium to nitrate. Nitrate must be reduced to ammonium in plant tissue before it is synthesized to amino acids, while ammonium is directly and immediately synthesized to amino acids after its uptake. Nitrate reductase is an enzyme that catalyzes the first and rate‐limiting step of nitrate assimilation, reducing nitrate to nitrite. It is a substrate‐inducible enzyme, and the capacity to induce nitrate reductase varies greatly among plant species. In vivo nitrate reductase activity (NRA) is generally measured as a nitrite production rate during incubation using fine cut pieces of plant tissue, and it is applicable as an indicator on plant nitrate use. Here we present in vivo NRA of leaves from a total of 108 species including arboreal trees, small trees, shrubs, herbs, a vine and a moss. For 75 of the species, NRA in fine roots was also determined. At least 20 species in sampled plants were imported and planted for scientific or industrial purposes, but most sampled species were native to Japan. Several inventory studies of plant NRA have been conducted, mainly in Europe, and they provided information on the species‐specific capacity of nitrate use by plants in Europe. However, to our best knowledge, there has been hitherto no published inventory of the NRA of plants in Japan where many endemic species are distributed. Our dataset contains plant NRA with species, family name, life form, leaf lifespan (evergreen or deciduous), growth stage, the season of sample collection, growth conditions (natural or cultivated) and other treatments/conditions when applicable. The data provided by this study may contribute to future works that require information regarding the plant species characteristics for nitrate use capacity or nitrate preference., SPECIAL FEATURE: Data rescue—collection of precious and laborious in situ observed data

Epiphytes face several constraints regarding nutrient acquisition: They are disconnected from soil minerals and they have to mainly rely on nutrients leached by precipitation and microbes. The cycad, Zamia pseudoparasitica Yates, is the only known strictly epiphytic gymnosperm, and it is endemic to Panamanian rainforests. Cycads have evolved specialized coralloid roots that host endophytic cyanobacteria specialized in nitrogen fixation. We collected coralloid roots from plants in the Omar Torrijos National Park, Provincia de Coclé. DNA was extracted from fresh inner coralloid roots, and the bacteriome was described using two molecular markers: rbcL‐rbcX (targeting cyanobacteria) and 16S (all bacteria). Sixteen samples were sequenced for rbcL‐rbcX yielding sequences belonging to a monophyletic group within the order Nostocales. One hundred and sixty‐five amplicon sequence variants (ASVs) were found in at least two of our 27 samples amplified for 16S. Nostocales, Rhizobiales, and Acetobacterales were the three most diverse and abundant orders of bacteria found within the coralloid roots, and the candidate phylum WPS‐2 was also found in many samples. We performed a de novo assembly from a single culture of the endophytic cyanobacteria. A phylogenomic analysis of the isolate places the cyanobacterium in a sister clade to mostly symbiotic taxa from mosses, liverworts, and lichens. Additionally, the isolate has genes putatively involved in symbiotic signaling, hormogonium differentiation, ammonium transport, nitrogen fixation, heterocyst differentiation, sulfate transport, and secondary metabolites. Although dominated by organisms with the capacity to fix nitrogen, coralloid roots are also inhabited by a diverse community of other taxa which may also play biologically important roles.

Ginkgo biloba is a famous living “fossil” and has played an important role in the evolution of the Plant Kingdom. Here, the complete chloroplast genome of G. biloba was sequenced and analysed. The chloroplast genome was 156,990 bp long and predicted to encode 134 genes including 85 protein-coding genes, 41 tRNA genes and 8 rRNA genes. The chloroplast genome has a typical quadripartite structure with a pair of inverted repeat regions (IRa and IRb, 17,732 bp), a large (LSC, 99,259 bp) and small single (SSC, 22,267 bp) copy region. After an extensive comparison to previously published gymnosperm plastomes, the gene content and organisation of G. biloba showed high divergence, although part was relatively conserved. The two typical IR regions in the G. biloba chloroplast genome were relatively shorter because it the ycf2 gene. In addition, it was obvious that the IR regions and gene loss were responsible for changes in chloroplast genome size and structure stability, which influenced plastome evolution in different gymnosperms. Phylogenetic analysis revealed that G. biloba is sister to cycads rather than to gnetophytes, cupressophytes, and Pinaceae. Overall, the study showed that the genomic characteristics of G. biloba would be of great help in the further research on the taxonomy, species identification and evolutionary history of gymnosperms, especially for their position in plant systematics and evolution.

Premise of research. Recent research on evolutionarily old species has uncovered mesophyll conductance (gm) as a key player in realized assimilation, but considerable variation was found. However, ...

Angiosperms that are biotically pollinated typically produce flowers with bright and contrasting colours that help to attract pollinators and hence contribute to the reproductive success of the species. This colourful array contrasts with the much less multicoloured reproductive structures of the four living gymnosperm lineages, which are mostly wind pollinated, though cycads and Gnetales are predominantly pollinated by insects that feed on surface fluids from the pollination drops. This review examines the possible evolutionary pathways and cryptic clues for flower colour in both living and fossil seed plants. It investigates how the ancestral flowering plants could have overcome the inevitable trade-off that exists between attracting pollinators and minimizing herbivory, and explores the possible evolutionary and biological inferences from the colours that occur in some living gymnosperms. The red colours present in the seed-cone bracts of some living conifers result from accumulation of anthocyanin pigments; their likely primary function is to help protect the growing plant tissues under particular environmental conditions. Thus, the visual cue provided by colour in flower petals could have first evolved as a secondary effect, probably post-dating the evolution of bee colour vision but occurring before the subsequent functional accumulation of a range of different flower pigments.

Understanding the differences in fine-root traits among different species is essential to gain a detailed understanding of resource conservation and acquisition strategies of plants. We aimed to explore whether certain root traits are consistent among subsets of species and characterize species together into meaningful community groups. We selected 11 woody species from different microbial symbiotic groups (ectomycorrhiza, arbuscular mycorrhiza, and rhizobia) and phylogenetic groups (broad-leaved angiosperms and coniferous gymnosperms) from the cool temperate forests of Nagano, Japan. We measured root architectural (branching intensity), morphological (root tissue density and specific root length), chemical (N and K concentrations), and anatomical (total stele and total cortex) traits. Significant differences were observed in all root traits, although many species did not differ from one another. Branching intensity was found to be the greatest variation in the measured root traits across the 11 woody species. The results of a principal component analysis of root traits showed a distinct separation between angiosperms and gymnosperms. We identified clusters of species based on their multidimensional root traits that were consistent with the different phylogenetic microbial association groups. Gymnosperm roots may be more resource conservative, while angiosperm roots may be more acquisitive for water and nutrients. We consider that the advances in root traits combination will make a breakthrough in our ability to differentiate the community groups rather than individual root trait.

Mosaicism has been confirmed in several studied old trees from both gymnosperms and angiosperms, in a pattern not always following the actual branching of the tree. Eight individuals from two gymnosperm and three angiosperm species of trees were studied for age-related mosaicism. We compare the level of intra-organismal genetic variability found within an individual old and an individual young tree of the same species to prove its relation to age. In five cases, we found statistically significant differences in intra-organismal genetic variability between young and old trees. In three cases of mosaicism, the constructed dendrogram corresponded with the actual branching of the tree, but it differed in the remaining two. We offer an explanation of the cases when the dendrogram does not correspond with the branching structure of the tree through the patterns of sectorial and mericlinal chimerism. In the studied gymnosperms, we found that the growth rate possibly influenced the level of intra-organismal variability, while in angiosperms the dependence was rather on age. The differences between angiosperm and gymnosperm molecular evolution and meristem stratification may play a role in this, but further research is needed in this area.

A new species of permineralized gymnosperm stem is described from volcaniclastic tuffs in Lopingian (late Permian) Xuanwei Formation from eastern Yunnan province, China. The stem comprises well-preserved tissues of the pith, primary and secondary xylem. Pith is divided into a thick-walled parenchymatous peripheral zone and an inner parenchymatous part. Primary xylem strands are numerous and indistinct with mesarch maturation. Secondary xylem is pycnoxylic with scalariform bordered pits on radial tracheid walls, with rays normally uniseriate or partly biseriate. Cross-field pits are mixed and including circular, elliptical and scalariform pitting. Comparisons indicate a close affinity with the contemporaneous plant Xuanweioxylon scalariforme, but differences with it lead to the erection of Xuanweioxylon damogouense sp. nov. We evaluate the systematic affinity of both species of Xuanweioxylon and conclude they represent conifers based on features of their wood anatomy. We consider the Xuanwei Formation includes at least four species of conifer, and show that X. damogouense possessed weak growth rings and false rings that suggest it grew in a climate with low seasonality and occasional periods of drought.

Late Quaternary low latitude tropical pollen study often pose difficulties during microscopic identifications due to their high diversification and complex nature This compendium is an illustrated guide to the identification of sporomorphs pollen and spores and non pollen palynomorphs NPPs preserved and recovered from gravity cores GCs in deltaic sedimentary records of the Niger Delta West Africa The precise and reliable identification of palynomorphs and non pollen palynomorphs NPPs is indispensable to permit comprehensive deduction to be made regarding past environmental change phytoecological and biogeographical distributions of fossil pollen and NPPs Identifications of key taxa in this study were best achieved through the direct inspection of reference materials mostly from Africa and to some extent around the globe Outlines of the technique s used to describe the taxa identified in this study were based on recording of the key species by observing the morphological descriptions wall composition size grain pores and sculptures through identification of microphotography components The generic groups of taxa identified were linked to their distinct phylogeny such as angiosperm gymnosperm pollen pteridophyte bryophyte spores and non pollen palynomorphs NPPs from West Africa The generic identification of grouping provides new insight on the basic distinction surrounding the vegetation habitat pollen spores and NPPs types Thus the current update would serve as the refinement to the previous study in the region based on the compiled taxa descriptions photomontage images of sporomorphs and NPPs This information could rejuvenate some of the misnomers on taxonomy phytoecology botanical family affinity and geographical origin of sporomorph and NPPs across the West Africa and around the globe through time