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To study the response characteristics of long-term mulching measures on soil enzyme activity and the limitation of microbial nutrients in the Loess Plateau Region, the study adopted a random block design and setup based on the long-term field positioning experiment conducted in 2008. Four types of inter-field management measures were established, including conventional no-mulch （NM）, straw mulch （SM）, mulch mulch （PM）, and ridge mulch （RPM）. The changes in soil nutrients and extracellular enzyme activities, their ecological stoichiometry and influencing factors under different cover measures, were investigated using a one-way analysis of variance, a stoichiometric model of soil extracellular enzymes, and redundancy analysis （RDA）. The results showed that mulching significantly affected soil basal nutrients （ P <0.05） and that the dissolubility of organic carbon, available nitrogen （AN）, and available phosphorus （AP） showed significant dynamic changes with plant growth. The extracellular enzyme activity of C, N, and P cycles showed a positive response and increased or changed by 21.03%-161.14%, 1.11%-60.68%, and 17.55%-37.66%, respectively, with the effect of SM and RPM being more significant. During long-term tillage, soil microorganisms as a whole faced C and N nutrient limitations. Under the mulching treatment, the vector angle increased significantly by 11.52%-23.17% in the early growth stage of crops, indicating that the microbial nitrogen limitation was alleviated, while the overall vector length showed an increasing trend and increased by 10.38%-84.38%. Additionally, the level of C restriction became stronger over time. The RDA analysis showed that soil water content, AN, and AP content were the key factors affecting the enzyme activity and their measurement relationship in the Loess Plateau. In summary, the implementation of SM and RPM tillage practices in the Loess Plateau Region had a stronger impact on soil nutrient properties and enzyme activities and could be combined to achieve better results. In the meantime, the appropriate application of nitrogen fertilizer should be considered to mitigate nutrient limitations. The research results can help better understand the influence of mulch on soil microbial nutrient utilization strategies in agricultural land and its regulatory mechanisms. Moreover, it provides theoretical foundations for the long-term sustainable development of the Loess Plateau hilly area.

Arabidopsis (Arabidopsis thaliana) H+-ATPase1 (AHA1), a plasma membrane (PM)-localized H+-ATPase, plays a key role in plant alkali stress tolerance by pumping protons from the cytoplasm to the apoplast. However, its molecular dynamics are poorly understood. We report that many C2-domain ABA-related (CAR) protein family members interact with AHA1 in Arabidopsis. Single or double mutants of CAR1, CAR6, and CAR10 had no obvious phenotype of alkali stress tolerance, while their triple mutants showed significantly higher tolerance to this stress. The disruption of AHA1 largely compromised the increased alkali stress tolerance of the car1car6car10 mutant, revealing a key role of CARs in AHA1 regulation during the plant's response to a high alkali pH. Furthermore, variable-angle total internal reflection fluorescence microscopy was used to observe AHA1-mGFP5 in intact Arabidopsis seedlings, revealing the presence of heterogeneous diffusion coefficients and oligomerization states in the AHA1 spots. In the aha1 complementation lines, alkali stress curtailed the residence time of AHA1 at the PM and increased the diffusion coefficient and particle velocity of AHA1. In contrast, the absence of CAR proteins decreased the restriction of the dynamic behavior of AHA1. Our results suggest that CARs play a negative role in plant alkali stress tolerance by interacting with AHA1 and provide a perspective to investigate the regulatory mechanism of PM H+-ATPase activity at the single-particle level., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Pyridine, a widespread aromatic heterocycle, features a sp 2 -hybridized nitrogen atom that can readily coordinate to metals, leading to distinctive achievements in catalysis. In stark contrast, π-coordination of pyridine and derivatives with transition metals is notably scarce, and the involvement of such activation mode in catalysis remains to be developed. Herein, we present amination reactions of aminopyridines that leverages the reversible π coordination with a ruthenium catalyst as the arenophilic π acid, rather than relying on the conventional κ-N coordination. Specifically, a transient η 6 -pyridine complex functions as the electrophile in the nucleophilic aromatic substitution with amines, providing a diverse array of products via the cleavage of the pyridyl C-N bond. In addition, this method can be employed to incorporate chiral amines and 15 N-labeled amines.

To develop gastric floating erodible plug pulse capsules with compound Danshen as the model drug, in order to realize the pulse release of traditional Chinese medicines. Through the study on impermeable capsules, optimized prescriptions, drug-containing rapid-release tablets and prescription screening, and erodible plug prescription and process, we successfully prepared compounded Danshen pulse capsule, so as to provide a new dosage form for controlling and treating heart disease to better cater to clinical demands.

The present paper studies the near-infrared spectroscopy of soluble solids content in navel orange that was influenced by different placement positions of the navel orange. According to the different angles between incident light and the straight line composed by navel orange stems and pit, the authors chose three different placement positions,vertical (90 degrees), parallel (0 degrees) and random(not including 0 degrees and 90 degrees). The authors acquired the semi-transmission spectrum of the navel orange placed in different positions in the wavelength range of 465-1 150 nm by the miniature fiber spectrometer USB4000, there were 336 navel orange samples in the experiment, 228 samples weree used as calibration set, and the rest 108 samples were used as prediction set. The authors used partial least-square regression combined with different pre-processing methods to establish the prediction model of SSC in navel orange with different placement positions. The result shows that when the angle is vertical the prediction models of SSC in navel orange are good, and the best correlation coefficient of the model is r = 0.93, RMSEC = 0.37%, r, = 0.88, and RMSEP = 0.49%.