The PtoTCP20-miR396d-PtoGRF15 module regulates secondary vascular development in Populus

Secondary vascular development is a key biological characteristic of woody plants and the basis of wood formation.Our understanding of gene expression regulation and dynamic changes in microRNAs(miRNAs)during secondary vascular development is still limited.Here we present an integrated analysis of the miRNA and mRNA transcriptome of six phase-specific tissues-the shoot apex,procambium,primary vascular tissue,cambium,secondary phloem,and secondary xylem-in Populus tomentosa.Several novel regulatory modules,including the PtoTCP20-miR396d-PtoGRF15 module,were identified during secondary vascular development in Populus.A series of biochemical and molecular experiments confirmed that PtoTCP20 activated transcription of the miR396d precursor gene and that miR396d targeted PtoGRF15 to downregulate its expression.Plants overexpressing miR396d(35S:miR396d)showed enhanced secondary growth and increased xylem production.Conversely,during the transition from primary to secondary vascular development,plants with downregulated PtoTCP20expression(PtoTCP20-SRDX),downregulated miR396 expression(35S:STTM396),and PtoGRF15 overexpression(35S:PtoGRF15)showed delayed secondary growth.Novel regulatory modules were identified by integrated analysis of the miRNA and mRNA transcriptome,and the regulatory role of the PtoTCP20-miR396d-PtoGRF15 signaling cascade in secondary vascular development was validated in Populus,providing information to support improvements in forest cultivation and wood properties.

High-performance flexible all-solid-state asymmetric supercapacitors based on binder-free MXene/cellulose nanofiber anode and carbon cloth/polyaniline cathode

The search for wearable electronics has been attracted great efforts,there is an ever-growing demand for all-solid-state flexible energy storage devices.However,it is a challenge to obtain both positive and negative electrodes with excellent mechanical strength and match positive and negative charges to achieve high energy densities and operate voltages to satisfy practical application requirements.Here,flexible MXene(Ti_(3)C_(2)Tx)/cellulose nanofiber(CNF)composite film negative electrodes(MCNF)were fabricated with a vacuum filtration method,as well as positive electrodes(CP)by combining polyaniline(PANI)with carbon cloth(CC)using an in-situ polymerization method.Both positive and negative free-standing electrodes exhibited excellent electrochemical behavior and bendable/foldable flexibility.As a result,the all-pseudocapacitance asymmetric device of MCNF//CP assembled with charge-matched between anode and cathode achieves an extended voltage window of 1.5 V,high energy density of 30.6 Wh·kg^(−1)(1211 W·kg^(−1)),86%capacitance retention after 5000 cycles,the device maintains excellent bendability,simultaneously.This work will pave the way for the development of all-pseudocapacitive asymmetric supercapacitors(ASC)with simultaneously preeminent mechanical properties,high energy density,wide operating voltage window.

Carbon Nanofibrous Sponge Made from Hydrothermally Generated Biochar and Electrospun Polymer Nanofibers

The objective of this study was to convert biochar,a byproduct generated from the hydrothermal process(in oxygen-limited environment)of biomass(e.g.,corn stover),into value-added product.In specific,three-dimensional(3D)biochar-containing precursor sponge,which was made by using electrospun polymer nanofibers as skeleton support,was fabricated via an innovative approach.The weight ratio of biochar to polymer(in the precursor sponge)was 2/1,and it appeared that the biochar weight ratio could be further increased.Upon heat treatments(i.e.,stabilization in air and carbonization in argon),the precursor sponge was converted into carbon nanofibrous sponge that had the porosity of~90 vol%,the BET surface area of~51.7 m^(2) g^(−1),and the carbon content of~95 wt%;and it was mechanically elastic/resilient.The electrochemical study indicated that,the carbon nanofibrous sponge could be utilized for making supercapacitor electrode with excellent rate capability and high kinetic performance.This study would not only demonstrate a high-value application of hydrothermally generated biochar,but also provide a facile while novel approach for the fabrication of carbon nanofibrous sponge which could be potentially used for various applications(particularly the energy storage application).