Reproductive biology of the "Brazilian pine" (Araucaria angustifolia-Araucariaceae): the pollen tube growth and the seed cone development.

KEY MESSAGE: In Araucaria angustifolia, the seed scale is part of the ovule, the female gametophyte presents a monosporic origin and arises from a coenocytic tetrad, and the pollen tube presents a single axis. The seed cone of conifers has many informative features, and its ontogenetic data may help interpret relationships among function, development patterns, and homology among seed plants. We reported the seed cone development, from pollination to pre-fertilization, including seed scale, ovule ontogeny, and pollen tube growth in Araucaria angustifolia. The study was performed using light microscopy, scanning electron microscopy, and X-ray microcomputed tomography (µCT). During the pollination period, the ovule arises right after the seed scale has emerged. From that event to the pre-fertilization period takes about 14 months. Megasporogenesis occurs three weeks after ovule formation, producing a coenocytic tetrad. At the same time as the female gametophyte's first nuclear division begins, the pollen tube grows through the seed scale adaxial face. Until maturity, the megagametophyte goes through the free nuclei stage, cellularization stage, and cellular growth stage. Along its development, many pollen tubes develop in the nucellar tissue extending straight toward the female gametophyte. Our observations show that the seed scale came out of the same primordia of the ovule, agreeing with past studies that this structure is part of the ovule itself. The formation of a female gametophyte with a monosporic origin that arises from a coenocytic tetrad was described for the first time in conifers, and the three-dimensional reconstruction of the ovule revealed the presence of pollen tubes with only one axis and no branches, highlighting a new pattern of pollen tube growth in Araucariaceae.

Function and molecular mechanism of a poplar placenta limited MIXTA gene in regulating differentiation of plant epidermal cells.

The placenta in fruits of most plants either desiccate and shrink as the fruits mature or develop further to form the fleshy tissues. In poplars, placental epidermal cells protrude collectively to produce catkin fibers. In this study, three carpel limited MIXTA genes, PdeMIXTA02, PdeMIXTA03, PdeMIXTA04, were find to specifically expressed in carpel immediately after pollination. Heterologous expression of the three genes in Arabidopsis demonstrated that PdeMIXTA04 significantly promoted trichomes density and could restore trichomes in the trichomeless mutant. By contrast, such functions were not observed with PdeMIXTA02, PdeMIXTA03. In situ hybridization revealed that PdeMIXTA04 was explicitly expressed in poplar placental epidermal cells. We also confirmed trichome-specific expression of the PdeMIXTA04 promoter. Multiple experimental proofs have confirmed the interaction between PdeMIXTA04, PdeMYC and PdeWD40, indicating PdeMIXTA04 functioned through the MYB-bHLH-WD40 ternary complex. Our work provided distinctive understanding of the molecular mechanism triggering differentiation of poplar catkins.

Comparative transcriptome analyses reveal insights into catkin bloom patterns in pecan protogynous and protandrous cultivars.

In perennial plants such as pecan, once reproductive maturity is attained, there are genetic switches that are regulated and required for flower development year after year. Pecan trees are heterodichogamous with both pistillate and staminate flowers produced on the same tree. Therefore, defining genes exclusively responsible for pistillate inflorescence and staminate inflorescence (catkin) initiation is challenging at best. To understand these genetic switches and their timing, this study analyzed catkin bloom and gene expression of lateral buds collected from a protogynous (Wichita) and a protandrous (Western) pecan cultivar in summer, autumn and spring. Our data showed that pistillate flowers in the current season on the same shoot negatively impacted catkin production on the protogynous 'Wichita' cultivar. Whereas fruit production the previous year on 'Wichita' had a positive effect on catkin production on the same shoot the following year. However, fruiting the previous year nor current year pistillate flower production had no significant effect on catkin production on 'Western' (protandrous cultivar) cultivar. The RNA-Seq results present more significant differences between the fruiting and non-fruiting shoots of the 'Wichita' cultivar compared to the 'Western' cultivar, revealing the genetic signals likely responsible for catkin production. Our data presented here, indicates the genes showing expression for the initiation of both types of flowers the season before bloom.

Palaearctic willow-catkin sawflies: a revision of the amentorum species group of Euura (Hymenoptera, Tenthredinidae).

The Euura amentorum species group is Holarctic, and in Europe it is most species-rich in the North. Their larvae develop entirely within the female catkins of Salix species: some species bore in the central stalk, whereas others live outside this and feed mainly on the developing seeds. Eight Palaearctic species are treated here as valid, and a key to these is provided. Males of five species are known. Two new species are described from northern Europe: Euura pohjola sp. n. and E. ursaminor sp. n. First records of E. itelmena (Malaise, 1931) from the West Palaearctic are presented. We propose seven new synonymies: Pontopristia montana Lindqvist, 1961 (junior secondary homonym in Euura) with Euura freyja (Liston, Taeger & Blank, 2009); Pontopristia brevilabris Malaise, 1921, Amauronematus fennicus Lindqvist, 1944, Pontopristia boreoalpina Lindqvist, 1961, Pontopristia punctulata Lindqvist, 1961, and Amauronematus pyrenaeus Lacourt, 1995 with Euura microphyes (Frster, 1854); and Pteronidea holmgreni Lindqvist, 1968 with Nematus umbratus Thomson, 1871. Lectotypes are designated for: Amauronematus fennicus Lindqvist, 1944, Nematus amentorum Frster, 1854, Nematus suavis Ruthe, 1859, Pontopristia brevilabris Malaise, 1921, Pontopristia itelmena Malaise, 1931, Pontopristia kamtchatica Malaise, 1931, Pontopristia lapponica Malaise, 1921, Pontopristia latiserra Malaise, 1921, Pontopristia romani Malaise, 1921, and Pristiphora amentorum var. nigripleuris Enslin, 1916. Many new host plant associations are recorded.

Unperceivable motion mimicking hygroscopic geometric reshaping of pine cones.

The hygroscopic deformation of pine cones, featured by opening and closing their scales depending on the environmental humidity, is a well-known stimuli-responsive model system for artificial actuators. However, it has not been noted that the deformation of pine cones is an ultra-slow process. Here, we reveal that vascular bundles with unique parallelly arranged spring/square microtubular heterostructures dominate the hygroscopic movement, characterized as ultra-slow motion with the outer sclereids. The spring microtubes give a much larger hygroscopic deformation than that of the square microtubes along the longitudinal axis direction, which bends the vascular bundles and consequently drives the scales to move. The outer sclereids with good water retention enable the vascular-bundle-triggered deformation to proceed ultra-slowly. Drawing inspiration, we developed soft actuators enabling controllable yet unperceivable motion. The motion velocity is almost two orders of magnitude lower than that of the same-class actuators reported, which made the as-developed soft actuators applicable in camouflage and reconnaissance.

Perception of eye contact, self-referential thinking and age.

Increased thinking about one's self has been proposed to widen the gaze cone, that is, the range of gaze deviations that an observer judges as looking directly at them (eye contact). This study investigated the effects of a self-referential thinking manipulation and demographic factors on the gaze cone. In a preregistered experiment (N = 200), the self-referential thinking manipulation, as compared to a control manipulation, did not influence the gaze cone, or the use of first-person pronouns in a manipulation check measuring self-referential processing. This may indicate a failure of the manipulation and participants' lack of effort. However, participants' age was significantly correlated with both measures: older people had wider gaze cones and used more self-referring pronouns. A second experiment (N = 300) further examined the effect of the manipulation and demographic factors on self-referential processing, and the results were replicated. These findings may reflect age-related self-reference and positivity effects.

Tea-polyphenol green fabricating catkin-like CuAg for electrochemical H2O2 detection.

Green fabrication of unique structural nanoparticles has always been of increasing interest in many fields. Herein, a facile and green strategy of fabricating catkin-like CuAg nanocomposites using tea-polyphenols as reduction agent is reported. As-prepared nanocomposites have been characterized by a series of analysis. Physical characterizations show the synthesised of nanocomposites whose catkin-like special morphology. The electrochemical detection hydrogen peroxide (H2O2) results show that, catkin-like CuAg nanocomposites have good sensitivity, stability and anti-interference and it could detect without any additional mediator or enzyme. Specifically, it shows good H2O2 sensitivity of 2.55 µA mM-1cm-2 with range of 0.1-120 mM. Therefore, the catkin-like CuAg nanocomposites prepared by an environmental-friendly synthetic strategy, would provide a good reference for other green syntheses in the future.

Electrospray mode discrimination with current signal using deep convolutional neural network and class activation map.

The electrospray process has been extensively applied in various fields, including energy, display, sensor, and biomedical engineering owing to its ability to generate of functional micro/nanoparticles. Although the mode of the electrospray process has a significant impact on the quality of micro/nano particles, observing and discriminating the mode of electrospray during the process has not received adequate attention. This study develops a simple automated method to discriminate the mode of the electrospray process based on the current signal using a deep convolutional neural network (CNN) and class activation map (CAM). The solution flow rate and applied voltage are selected as experimental variables, and the electrospray process is classified into three modes: dripping, pulsating, and cone-jet. The current signal through the collector is measured to detect the deposition of electrospray droplets on the collector. The 1D CNN model is trained using frequency data converted from the current data. The model exhibits excellent performance with an accuracy of 96.30%. Adoption of the CAM configuration enables the model to provide a discriminative cue for each mode and elucidate the decision-making process of the CNN model.

A Late Devonian tree lycopsid with large strobili and isotomous roots.

Tree lycopsids prospered in the Late Devonian and constituted a major part of the Late Paleozoic forest ecosystem that deeply impacted the Earth's climate. However, the fertile organs of these early tree lycopsids display low morphological disparity, which has hampered further knowledge about their ecological habit. Here, we report Omprelostrobus gigas gen. et sp. nov. from the Upper Devonian (Famennian) Wutong Formation at Changxing, Zhejiang, China. The collection includes aerial axes, strobili and associated roots. The strobili are the largest among coeval lycopsids to our knowledge, and are divided into proximal and distal portions by dimorphic sporophylls with differentiated laminae and probable strong photosynthetic capacity. The associated but not attached roots displaying multiple isotomous branches lack rootlets and typical rootlet scars. The varied strobili sizes of early tree lycopsids were relatively independent of their body plan, but the large strobili could suggest increased reproductive investment to overcome the disadvantages of the disturbed flooded habitat.

Mathematical analysis of the effect of process conditions on the porous structure development of activated carbons derived from Pine cones.

This paper presents the results of a study on the influence of the degree of impregnation and activation temperature on the formation of the porous structure of activated carbons (ACs) obtained from Pine cones by the chemical activation process using potassium hydroxide as an activator. The advanced new numerical clustering based adsorption analysis (LBET) method, together with the implemented unique numerical procedure for the fast multivariant identification were applied to nitrogen and carbon dioxide adsorption isotherms determined for porous structure characterization of the ACs. Moreover, the Quenched Solid Density Functional Theory (QSDFT) method was chosen to determine pore size distributions. The results showed a significant influence of the primary structure of Pine cones on the formation of the porous structure of the developed ACs. Among others, it was evidenced by a very high degree of surface heterogeneity of all the obtained ACs, irrespective of the degree of impregnation with potassium hydroxide and the activation temperature. Moreover, the analysis of carbon dioxide adsorption isotherms showed, that the porous structure of the studied ACs samples contains micropores accessible only to carbon dioxide molecules. The results also showed a significant advantage of the LBET method over those conventionally used for porous structure analysis based on Brunauer-Emmett-Teller (BET) and Dubinin-Raduskevich (DR) equations, because it takes into account surface heterogeneities. The novel analyses methods were more fully validated as a reliable characterization tool, by extending their application to the isotherms for ACs developed from the same precursor by phosphoric acid activation, and for samples arising from these ACs, further subjected to additional post-treatments. The effect of the raw material used as precursor was moreover analysed by comparison with previous reported results for other ACs. The complementarity of the results obtained with the LBET and QSDFT methods is also noteworthy, resulting in a more complete and reliable picture of the analyzed porous structures.

Detailed seed cone morpho-anatomy of the Prumnopityoid clade: an insight into the origin and evolution of Podocarpaceae seed cones.

BACKGROUND AND AIMS: Seed cone traits are significant for understanding the evolutionary history of conifers. Podocarpaceae has fleshy cones with a distinct morphology compared with other conifers. However, we have a poor understanding of the seed cone morphology of the Prumnopityoid clade and within Podocarpaceae. This study presents detailed seed cone morpho-anatomy and the evolution of fleshy structures traits in the Prumnopityoid clade. METHODS: We investigated the detailed seed cone morpho-anatomy of selected species from the nine genera using the histological method. The evolution of morpho-anatomical traits was assessed using ancestral state reconstruction methods. KEY RESULTS: The Prumnopityoid clade has evolved fleshy seed cones using different functional structures (e.g. aril, epimatium, bracts or receptaculum) and fleshiness is an ancestral trait in the clade. An epimatium is present in all genera except Phyllocladus, but with different structural morphologies (e.g. a fleshy asymmetrical cup-like epimatium or an epimatium that is fused with the integument, forming a fleshy sarcotesta-like seed coat). In all species with fleshy sarcotesta-like seed coats, the endotesta is hard and woody, forming a sclerotesta-like structure and the epimatium and exotesta are fused, forming a fleshy sarcotesta-like structure. CONCLUSIONS: This study highlights that the Prumnopityoid clade has an amazing diversity of structures and complex evolutionary patterns. Fleshiness is an ancestral trait of the clade and has been achieved via diverse evolutionary pathways and structures. This clade has four distinct seed cone types, i.e. drupe-like, receptaculate, arilloid and dacrydioid cones, based on morpho-anatomical structures and traits. The macrofossil record also demonstrates the presence of several structures and traits.

[Discussion on moxibustion practice of the Han medical bamboo slips unearthed in Wuwei and Juyan regions of Gansu province].

Through collecting the relevant moxibustion records of Han medical bamboo slips unearthed in Wuwei and Juyan regions of Gansu province, the situation and characteristics of clinical practice of moxibustion were summarized. In Wuwei Han medical bamboo slips, the contraindications of moxibustion were recorded, with age and time involved. Juyan Han medical bamboo slips mainly recorded the methods of moxibustion at the acupoints located on the back of the body, with clear emphasis and requirement of acupoint selection, single acupoint moxibustion and moxibustion quantity (the numbers of moxa cone) included. These records on bamboo slips initially display the practice and development of moxibustion in Gansu and other northwestern regions of China in the Han Dynasty, providing a certain instruction for the literature research of moxibustion of the excavated Han medical bamboo slips.

The Structural and Mechanical Basis for Passive-Hydraulic Pine Cone Actuation.

The opening and closing of pine cones is based on the hygroscopic behavior of the individual seed scales around the cone axis, which bend passively in response to changes in environmental humidity. Although prior studies suggest a bilayer architecture consisting of lower actuating (swellable) sclereid and upper restrictive (non- or lesser swellable) sclerenchymatous fiber tissue layers to be the structural basis of this behavior, the exact mechanism of how humidity changes are translated into global movement are still unclear. Here, the mechanical and hydraulic properties of each structural component of the scale are investigated to get a holistic picture of their functional interplay. Measurements of the wetting behavior, water uptake, and mechanical measurements are used to analyze the influence of hydration on the different tissues of the cone scales. Furthermore, their dimensional changes during actuation are measured by comparative micro-computed tomography (µ-CT) investigations of dry and wet scales, which are corroborated and extended by 3D-digital image correlation-based displacement and strain analyses, biomechanical testing of actuation force, and finite element simulations. Altogether, a model allowing a detailed mechanistic understanding of pine cone actuation is developed, which is a prime concept generator for the development of biomimetic hygromorphic systems.

Phytohormone profiles and related gene expressions after endodormancy release in developing Pinus tabuliformis male strobili.

Development after endo-dormancy release ensures perennial plants, such as forest trees, proper response to environmental changes and enhances their adaptability. In northern hemisphere, megasporophore and microsporophore of conifers undergo dormancy to complete their development. Here combined with transcriptome data, we used high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (ESI-HPLC-MS/MS) to quantitatively analyse the various hormones (Abscisic Acid (ABA), 3-Indoleacetic acid (IAA), Gibberellins (GAs), Cytokinin (CTK), Jasmonic acid (JA) and Salicylic acid (SA)) of Chinese pine (Pinus tabuliformis Carr.) male strobili after endo-dormancy release. More specifically, we analysed endogenous hormones and their related-genes and verified the important role of ABA in plants growth and development. We observed rapid decrease in ABA content after dormancy release, resulting in reducing the inhibitory effect on male strobili growth. Similarly, rapid drop in ABA/GA ratio was observed and was associated with the start of male strobili growth and development. Combined with transcriptome data, we found that HAB2-SnRK2.10 played a central role in the ABA pathway in the entire network of hormones regulating male strobili development. Due to external environment warming, the differentially expressed HAB2-SnRK gene led to ABA content rapid decline, thus initiating male strobili growth. We constructed a network of hormone-regulated development to understand the interactions between hormones after male strobili dormancy release of male strobili. This study provided essential foundations for studying megasporophore and microsporophore growth mechanism after endo-dormancy and offered new ideas for flower development in gymnosperms and angiosperms.

Isolation and quantification of diarylheptanoids from European hornbeam (Carpinus betulus L.) and HPLC-ESI-MS/MS characterization of its antioxidative phenolics.

Detailed polyphenol profiling of European hornbeam (Carpinus betulus L.) bark, leaf, male and female catkin extracts was performed by high-performance liquid chromatography-diode array detection coupled to tandem mass spectrometry (HPLC-DAD-MS/MS). A total of 194 compounds were characterized and tentatively identified. Gallo- and ellagitannins dominated in the methanol extracts, while flavonol glycosides and methoxylated flavones prevailed in the ethyl acetate samples. In the quest for diarylheptanoids, twelve compounds were isolated by the combination of subsequent reversed-phase flash chromatographic and high-performance liquid chromatographic methods. The structural elucidation of the isolated components was performed by ultrahigh-performance liquid chromatography-Orbitrap mass spectrometry (UHPLC-Orbitrap-MS) as well as 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. Six known cyclic diarylheptanoids, together with a new compound were described in Carpinus betulus for the first time. The occurrence of a linear diarylheptanoid and a lignan has also been unprecedented in the genus Carpinus. Moreover, three known flavonol glycosides were isolated. Based on the identification of characteristic fragment ions, a new mass spectrometric fragmentation pathway for meta,meta-cyclophane-type diarylheptanoids was proposed. Quantities of the four major cyclic diarylheptanoids in European hornbeam were determined by a validated UHPLC-DAD method for the first time. The antioxidant properties of the extracts and the isolated compounds were assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Contribution of the individual constituents to the total radical scavenging activity of the samples was evaluated by an off-line DPPH-HPLC-DAD method. This allowed the identification of gallo- and ellagitannin derivatives as the constituents being primarily responsible for the antioxidant capacity of the extracts.

Early colonization of Protea flowers enable dominance of competitively weak saprobic fungi in seed cones, benefitting their hosts.

Sporothrix and Knoxdaviesia fungi use pollinators to colonize Protea flowers at anthesis. These saprobes remain dominant in the nutrient-rich, fire-retardant Protea seed-cones (infructescences) for at least a year after flowering. We tested the hypothesis that they competitively exclude potentially detrimental fungi from infructescences during this time. We compared seed set and longevity of infructescences containing Sporothrix and Knoxdaviesia vs. those that contain 'contaminant' saprobes. Hereafter we evaluated their competitive abilities against the 'contaminant' saprobes. Infructescences devoid of Sporothrix and Knoxdaviesia were dominated by Penicillium cf. toxicarium, Cladosporium cf. cladosporoides and Fusarium cf. anthophilum. Sporothrix and Knoxdaviesia presence did not affect seed viability, but infructescences persisted longer than those colonised by 'contaminant' fungi. The 'contaminant' species were stronger competitors than Sporothrix and Knoxdaviesia. However, Sporothrix and Knoxdaviesia could defend captured space well against 'contaminant' species. This effect was enhanced when fungal taxa grew on media prepared from their usual Protea host species, clarifying their dominance and host consistency observed in the field. Sporothrix and Knoxdaviesia from Protea are therefore weak competitors against common saprobes, especially when growing on alternative hosts, and need to colonise flowers very early (before colonization by other fungi) to dominate in this environment. They may delay seed release from infructescences longer than if these are colonised by other saprobes, increasing chances of seed release to occur after fire, when conditions are more favourable for Protea recruitment.

An Interference Inspection Algorithm of Limb and Hexapod Frame in the Treatment of Lower Limb Deformity.

Pre-operative correction trajectory planning is one of the important aspects of deformity correction. Avoidance of limb-frame interference is essential to verify the implementability of the preplanned correction trajectory, as well as to maintain the continuity and security of the correction strategy. In this study, a novel interference inspection algorithm is developed to investigate the interaction of the limb and hexapod frame in the treatment of lower limb deformities. The algorithm is built on a minimum distance model of the cone frustum busbar and cylindrical axis using vector analysis. A predefined trajectory is generated by Cartesian coordinate path control. Subsequently, an interference case is performed through numerical simulation and motion simulation. The results show that the conclusion of numerical simulation and motion simulation is consistent, which prove the feasibility of the algorithm. The results also show that it is possible to identify the riskiest struts, which are prone to interfere with the limb, and the riskiest positions. The proposed algorithm can support the clinician in selecting the suitable frame configuration to avoid interference. The algorithm solves the problem that the interference can only be judged by clinical observation in the clinic.

Biomass poplar catkin fiber-based superhydrophobic aerogel with tubular-lamellar interweaved neurons-like structure.

Superhydrophobic aerogels are attractive candidates in controlling oil spills. The major challenges for existing aerogels are the construction of mechanical endurance as well as accessible of building materials. Herein, a newfangled biomass superhydrophobic aerogel (M-PCF/CS) with both superior compressibility and oil caption speed is fabricated by assembling poplar catkin fiber (PCF) hollowed-out shell of 330 nm and chitosan (CS) into tubular-lamellar interweaved neurons-like structure. The resultant aerogels (porosity ~ 96.12%), with flexuous PCF as the elastic buffer and second-pore capillaries, exhibit large longitudinal and transverse compressibility, endurable fatigue tolerance, fast oil sorption rate with a capacity of 28.8-78.1 g/g at 5-25 s. In parallel, the aerogels are tolerant of NaCl, UV radiation, and organic solvents without superhydrophobic variation and a case of oil spill remediation via pump-supported experiment shows that the aerogels facilely achieve continuous oil recycling from seawater by 23052-43956 L·m-2·h-1. Furthermore, the resultant M-PCF/CS, with assistance of an oscillator, can be applied to separate oil/water emulsions with efficiency of 98.07-99.11%. The successful fabrication of this material provides a new design strategy for the construction of mechanically robust aerogels for speedy and economical cleanup of oil pollutants from water.