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To improve our understanding of the origin and evolution of mycoheterotrophic plants, we here present the chromosome-scale genome assemblies of two sibling orchid species: partially mycoheterotrophic Platanthera zijinensisand holomycoheterotrophic Platanthera guangdongensis. Comparative analysis shows that mycoheterotrophy is associated with increased substitution rates and gene loss, and the deletion of most photoreceptor genes and auxin transporter genes might be linked to the unique phenotypes of fully mycoheterotrophic orchids. Conversely, trehalase genes that catalyse the conversion of trehalose into glucose have expanded in most sequenced orchids, in line with the fact that the germination of orchid non-endosperm seeds needs carbohydrates from fungi during the protocorm stage. We further show that the mature plant of P. guangdongensis, different from photosynthetic orchids, keeps expressing trehalase genes to hijack trehalose from fungi. Therefore, we propose that mycoheterotrophy in mature orchids is a continuation of the protocorm stage by sustaining the expression of trehalase genes. Our results shed light on the molecular mechanism underlying initial, partial and full mycoheterotrophy.

WebComparing the whole genome sequence of Apostasia shenzhenicawith transcriptome and genome data from five orchid subfamilies permits the reconstruction of an ancestral gene toolkit, providing insight into orchid origins, evolution and diversification.

Mixed-phase ZnMgO (m-ZMO) thin films with a single absorption edge tuning from ∼3.9 to ∼4.8 eV were realized on a-face sapphire (a-Al2O3) by plasma-assisted molecular beam epitaxy. The small lattice mismatch of both ZnO and MgO with a-Al2O3should be responsible for the single and controllable absorption edge. Metal–semiconductor–metal (MSM) photodetectors were fabricated based on these m-ZMO films, and the devices have the single cutoff wavelength, which can be tuned from 335 to 275 nm. These devices possess low dark current (78 pA for m-Z0.67M0.33O, 11 pA for m-Z0.59M0.41O, and 4 pA for m-Z0.39M0.61O at 40 V) and high responsivity (434 A/W for m-Z0.67M0.33O, 89.8 A/W for m-Z0.59M0.41O, and 3.7 A/W for m-Z0.39M0.61O at 40 V). Further response study reveals that the 90–10% decay time of m-Z0.67M0.33O, m-Z0.59M0.41O, and m-Z0.39M0.61O is around 37, 30, and 0.7 ms, respectively. Large amounts of heterojunction interfaces between wurtzite ZMO and cubic rock-salt ZMO could be responsible for the low dark current and high responsivity of our mixed-phase devices. The excellent comprehensive performance of m-ZMO UV photodetectors on a-Al2O3suggests that m-ZMO UV photodetectors should have great applied potential.

A series of Co/SBA-16 catalysts were prepared by the incipient wetness impregnation method and characterized with N2physisorption, X-ray diffraction, H2-temperature-programmed reduction, hydrogen chemisorption and transmission electron microscopy techniques. It was found that the Co0dispersion decreased with increasing cobalt loading, being consistent with the increase of Co3O4crystallite sizes and the decrease of BET surface area. The Co/SBA-16 catalysts show high CO conversion, low C1selectivity, high C5+hydrocarbon selectivity, and especially high selectivity towards diesel fraction.

The tunable hybridized quadrupole plasmons and their strong coupling with excitons have been demonstrated in ZnMgO/Ag nanoclusters (NCs) system. By adjusting the density of the random Ag NCs, the hybridized quadrupole resonance with strong intensity can be obtained due to the asymmetry Fano-like interference. Owing to a good energy match between hybridized quadrupole plasmons and excitons of ZnMgO, a giant near-band-edge UV emission enhancement was realized. The finite difference time-domain method was used to demonstrate the formation of the tunable hybridized quadrupole resonance in the short wavelength range. This novel method for enhancing the UV emission, associated with the hybridized quadrupole plasmons, may pave the way for the further development of high-efficiency UV light-emitting diodes and laser diodes.

One of the key technologies in future optoelectronics is control of excitons in oxide materials by the coupling with plasmons on noble metal surfaces. Optical properties of ZnO nanowires decorated with Au nanoparticles were studied to understand fundamental mechanism of the coupling and to develop optoelectronic devices with new functionalities. Light intensity at the main peak position in the photoluminescence (PL) spectra of ZnO nanowires was enhanced with the coverage of Au nanoparticles. Lifetime of excitons excited optically decreased by the decoration of Au nanoparticles. Understanding of the coupling between excitons and plasmons leads to optical control of excitons and will pave the way for new type of optoelectronic devices.

Construct the model of the end-point ingredient prediction of low carbon ferrochrome smelt based on the working condition of electrothermal silicon method using the method of multi-scale support vector machiness information fusion, where the best decomposition scale information is according to different smelt working conditions using Levenberg-Marquart algorithm to optimize the design, smelt working condition is judged by Bayesian classifier. Researches have proved that this method can improve the precision of prediction and make the prediction result more accurate, reasonable and practical.

Automotive airbag assembly process is complex and nonlinear, and one of its characteristics is that the accuracy of making the threshold comparison for fault diagnosis using field multi-sensor measured value is not high,. In this article, adopt self-organizing feature mapping network SOM to realize the fault diagnosis of automotive airbag assembly process, constitute the field function of SOM through wavelet functions, form sub-excitatory neuron to update weights, avoid SOM local optimum, so improve the accuracy of fault diagnosis of automotive airbag assembly process.

To solve the problems of large flux linkage and torque ripple, difficulty to accurately control at very low speed in the conventional direct torque control (DTC) of permanent magnet synchronous motor (PMSM), the chattering free fast terminal sliding mode (FTSM) control is introduced into the PMSM DTC. The proposed control scheme not only preserves fast torque response merit, but also associates with the high robustness of terminal sliding mode. It can drive torque ripple to converge to the equilibrium point in finite time, reduce steady state error, has stronger robustness to motor parameter and disturbance,and it attenuates the chatter. This stability of system is proved by Lyapunov theorem in this paper. The simulation results are presented to the feasibility and effectiveness of this method.

Abstract A new pollination mechanism is reported of an orchid species, Bulbophyllum penicillium, based on a field observation in Southeast Yunnan of China. This species has a sensitive lip, and there is a distance of 2–3 mm between it and column apex. Once the lip is touched by a landing insect, it will move up and down or swing left and right continuously, just like a moving caterpillar. By suck a lip movement, the pollinator, a very small fruit fly (Drosophilasp.) ca. 1 mm in height, will be pressed toward the column apex where anther and stigma are located, and then cross-pollination takes place. This unique mode of pollination, depending on the movement of lip rather than insect itself, has never been found before in either Orchidaceae or other families of angiosperms.

The marvelously diverse Orchidaceae constitutes the largest family of angiosperms. The genus Cymbidiumin Orchidaceae is well known for its unique vegetation, floral morphology, and flower scent traits. Here, a chromosome-scale assembly of the genome of Cymbidium ensifolium(Jianlan) is presented. Comparative genomic analysis showed that C. ensifoliumhas experienced two whole-genome duplication (WGD) events, the most recent of which was shared by all orchids, while the older event was the τ event shared by most monocots. The results of MADS-box genes analysis provided support for establishing a unique gene model of orchid flower development regulation, and flower shape mutations in C. ensifoliumwere shown to be associated with the abnormal expression of MADS-box genes. The most abundant floral scent components identified included methyl jasmonate, acacia alcohol and linalool, and the genes involved in the floral scent component network of C. ensifoliumwere determined. Furthermore, the decreased expression of photosynthesis-antennae and photosynthesis metabolic pathway genes in leaves was shown to result in colorful striped leaves, while the increased expression of MADS-box genes in leaves led to perianth-like leaves. Our results provide fundamental insights into orchid evolution and diversification.

MgZnO heterostructure light-emitting devices (LEDs) have been fabricated from p-Mg_0.35Zn_0.65O/n-Mg_0.20Zn_0.80O structures, and the p-type Mg_0.35Zn_0.65O film was realized using a lithium–nitrogen codoping method. Obvious ultraviolet emission peaked at around 355 nm dominates the electroluminescence (EL) spectra of the device at room temperature, which comes from the near-band-edge emission of the n-type Mg_0.20Zn_0.80O film. This is the first report on MgZnO heterostructured LEDs and the shortest EL emission ever reported in ZnO-based p-n junction LEDs to the best of our knowledge.

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The article offers information on several aspects related to the orchid genus Paraholcoglossum including its history, taxonomy and its species. It mentions that this genus was established in 2011 and it is mainly distributed in China and adjacent countries. It further states that this genus has three species including Paraholcoglossum amesianum, Paraholcoglossum subulifolium and Paraholcoglossum auriculatum. Several photographs depicting these species are also presented.