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[Objective] To meet the requirements of constant and adjustable rotation speed of rolling barrel and constant rotation speed of rolling barrel when tea is rolled. [Methods] The 6CR-55 single-column disc twisting machine was used as the research object in this paper. Fuzzy control algorithm and PWM closed-loop control method were investigated to study the stable control of rotating speed of rolling drum, and established the mathematical model of rotating speed control system of rolling drum based on the STM32 single-chip microcontroller. The simulation experiments of uncorrected, PID and fuzzy PID algorithm control system were carried out by MATLAB. [Results] Compared with uncorrected control and PID control, the output speed of the fuzzy PID speed control system was more stable and accurate, and the anti-interference ability was stronger. The speed error was controlled within 3 r/min. [Conclusion] The fuzzy PID control method can meet the requirement for the constant and adjustable rotating speed of the rolling drum during tea rolling, and improve the rate of tea forming and cell breakage.

Summary: Legume nodulation requires light perception by plant shoots and precise long‐distance communication between shoot and root. Recent studies have revealed that TGACG‐motif binding factors (GmSTFs) integrate light signals to promote root nodulation; however, the regulatory mechanisms underlying nodule formation in changing light conditions remain elusive.Here, we applied genetic engineering, metabolite measurement, and transcriptional analysis to study soybean (Glycine max) nodules.We clarify a fine‐tuning mechanism in response to ultraviolet B (UV‐B) irradiation and rhizobia infection, involving GmUVR8‐dependent UV‐B perception and GmSTF3/4‐GmMYB12‐GmCHS‐mediated (iso)flavonoid biosynthesis for soybean nodule formation. GmUVR8 receptor‐perceived UV‐B signal triggered R2R3‐MYB transcription factors GmMYB12‐dependent flavonoid biosynthesis separately in shoot and root. In shoot, UV‐B‐triggered flavonoid biosynthesis relied on GmUVR8a, b, c receptor‐dependent activation of GmMYB12L‐GmCHS8 (chalcone synthase) module. In root, UV‐B signaling distinctly promotes the accumulation of the isoflavones, daidzein, and its derivative coumestrol, via GmMYB12B2‐GmCHS9 module, resulting in hypernodulation. The mobile transcription factors, GmSTF3/4, bind to cis‐regulatory elements in the GmMYB12L, GmMYB12B2, and GmCHS9 promoters, to coordinate UV‐B light perception in shoot and (iso)flavonoid biosynthesis in root.Our findings establish a novel shoot‐to‐root communication module involved in soybean nodulation and reveal an adaptive strategy employed by soybean roots in response to UV‐B light. [ABSTRACT FROM AUTHOR]

Homeodomain-containing transcription factors (Htfs) play important roles in animals, fungi, and plants during some developmental processes. Here, a homeodomain-containing transcription factor Po Htf1 was functionally characterized in the cellulase-producing fungi Penicillium oxalicum 114-2. Po Htf1 was shown to participate in colony growth and conidiation through regulating the expression of its downstream transcription factor BrlA, the key regulator of conidiation in P. oxalicum 114-2. Additionally, Po Htf1 inhibited the expression of the major cellulase genes by coordinated regulation of cellulolytic regulators CreA, AmyR, ClrB, and XlnR. Furthermore, transcriptome analysis showed that Po Htf1 participated in the secondary metabolism including the pathway synthesizing conidial yellow pigment. These data show that Po Htf1 mediates the complex transcriptional-regulatory network cascade between developmental processes and cellulolytic gene expression in P. oxalicum 114-2. Our results should assist the development of strategies for the metabolic engineering of mutants for applications in the enzymatic hydrolysis for biochemical production. [ABSTRACT FROM AUTHOR]

In order to improve the accuracy of near infrared (NIR) spectroscopy identification methods for tea at different altitude, the non-linear manifold dimensionality reduction methods of locally linear embedding (LLE) and laplacian eigenmaps (LE) were used to reduce the dimension of NIR spectral data, and compared with non-linear (KPCA) and linear (PCA) dimensional reduction methods. Discrimination models were established for tea at different altitude based on different dimensional reduction methods and least squares support vector machine (LSSVM) algorithm. Visualization of different dimensionality reduction results show that data processed by KPCA and PCA methods were more discrete. In particular, there were more overlaps between 400-800 m and 800-1 200 m samples. However, the same kind of sample points could be gathered well in three-dimensional space by the nonlinear manifold dimensionality reduction methods can. Tea at different altitude could be easily separated and the aggregation effect of the LE was better than that of the LLE. The results of models indicate the LE_LSSVM model had the best performance, with the prediction set accuracy and Kappa value of 100% and 1.00 respectively. Compared with PCA_LSSVM, KPCA_LSSVM and LLE_LSSVM models, the accuracy of prediction set was improved by 1.7%, 1.7%, 3.3% and Kappa values increased by 0.025, 0.03, and 0.05. The results show that LE and other nonlinear manifold dimensionality reduction methods were effective in reducing dimension of near infrared spectral data, simplifying model complexity, and improving model precision. The study provides a new means for rapid detecting for tea quality research. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering spectroscopy method coupled with colloidal gold was used to detect and characterize phosalone pesticide in pakchoi. Theoretical and experimental Raman spectra were compared to analyze and identify the assignment of vibrations. Pakchoi samples containing phosalone pesticide residues were prepared and extracted for Raman spectra acquirement and gas chromatography-mass spectrometry measurement. A statistical regression analysis method was applied for the detection of phosalone residues. This analytical method was validated by predicted recovery and the paired-samplesTtest with five unknown samples. This study demonstrates that surface-enhanced Raman scattering (SERS) method is capable of detecting phosalone residues in pakchoi quickly and accurately. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman spectroscopy (SERS), coupled with characteristic peak screening methods, was developed for analyzing chlorpyrifos (CM) pesticide residues in rice. Au nanoparticles (AuNPs) were prepared as Raman signal enhancement. Magnesium sulfate (MgSO4), primary secondary amine (PSA), and C18 were used to purify the rice extraction. A successive projections algorithm (SPA) was performed to identify the optimal characteristic peaks of CM in rice from full Raman spectroscopy. Support vector machine (SVM) and partial least squares (PLS) were implemented to investigate the quantitative analysis models. The results demonstrated that six Raman peaks such as 671, 834, 1016, 1114, 1436, and 1444 cm−1 were selected by the SPA and SVM models and had better performance using six peaks (only 0.92% of the full spectra variables) with R 2 p = 0.97, RMSEP = 2.89 and RPD = 4.26, and the experiment time for a sample was accomplished within 10 min. Recovery for five unknown concentration samples was 97.45–103.96%, and T -test results also displayed no obvious differences between the measured value and the predicted value. The study stated that SERS, combined with characteristic peak screening methods, can be applied to rapidly monitor the chlorpyrifos residue in rice. Graphical Abstract [ABSTRACT FROM AUTHOR]

[Display omitted] • High-level roasting decreased cis / trans flavanol ratio. • Two chlorogenic acid lactones were identified as new markers of tea roasting. • Furfuryl methyl ether was solely found in tea roasted at moderate intensity. • Various heterocycles and aldehydes were key aromas with roasted and fatty odors. Roasting is crucial for the distinct flavor of Wuyi rock tea (WRT). This study applied untargeted metabolomics to investigate the effects of roasting on 139 WRT samples roasted at light fire (LF) or moderate fire (MF) intensities. Compared to LF, MF roasting led to a decrease in the cis / trans flavanol ratio by 56% and theanine by 85%, while increasing the levels of N -ethyl-2-pyrrolidione-substituted flavanols (EPSFs), flavonol aglycones and flavone C -glycosides. Two new roast markers, 3- p -coumaroyl 1,5-lactone and 4- p -coumaroyl 1,5-lactone, were identified in WRT and their formation increased with roasting temperature. MF roasting facilitated the formation of diverse heterocycles (e.g. , pyrazines) and aldehydes (e.g. , (Z)-4-heptenal and (E , E)-2.4-decadienal) that contributed to the augmented roasted and fatty odors in WRT. Additionally, the Maillard product furfuryl methyl ether was solely detected in MF samples. These findings provide novel insights into roast markers in WRT with implications for improving quality control measures during tea roasting. [ABSTRACT FROM AUTHOR]