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Highly diverse exoenzymes mediate the energy flow from substrates to the multitrophic microbiota within the soil decomposer micro‐food web. Here, we used a "soil enzyme profile analysis" approach to establish a series of enzyme profile indices; those indices were hypothesized to reflect micro‐food web features. We systematically evaluated the shifts in enzyme profile indices in relation to the micro‐food web features in the restoration of an abandoned cropland to a natural area. We found that enzymatic C:N stoichiometry and decomposability index were significantly associated with substrate availability. Furthermore, the higher Shannon diversity index in the exoenzyme profile, especially for the C‐degrading hydrolase, corresponded to a greater microbiota community diversity. The increased complexity and stability of the exoenzyme network reflected similar changes with the micro‐food web networks. In addition, the gross activity of the enzyme profile as a parameter for soil multifunctionality, effectively predicted the substrate content, microbiota community size, diversity, and network complexity. Ultimately, the proposed enzymic channel index was closely associated with the traditional decomposition channel indices derived from microorganisms and nematodes. Our results showed that soil enzyme profile analysis reflected very well the decomposer food web features. Our study has important implications for projecting future climate change or anthropogenic disturbance impacts on soil decomposer micro‐food web features by using soil enzyme profile analysis. Highlights: Soil enzyme profile analysis for indicating decomposer micro‐food web features was first proposed.Diversity indication utilities for contrasting enzyme profiles were different.Protozoa channel index and enzymatic channel index were proposed. [ABSTRACT FROM AUTHOR]

Selecting the appropriate indicators and measuring time point numbers is important for accurately examining the shift in soil gross decomposition channel structure. Through a selected case study on a natural forest vs. rainfed arable system over a two-month-long experiment, the utility of three commonly employed indicators (fungi to bacteria ratio (F:B), fungivore to bacterivore ratio (FF:BF), and glucosamine to muramic acid ratio (GlcN:MurN)) were compared to reflect the shift in soil gross decomposition channel structure. The requirement of measuring the time point numbers for the three indicators was also assessed, and we suggest a potential methodology. Our results revealed that the GlcN:MurN ratio was more reliable for assessing the shifts in gross decomposition channel structure for long-term land use changes, while it was less sensitive to short-term drought compared with the other two indicators. The F:B ratio was more applicable than the FF:BF ratio for reflecting both long- and short-term changes. Furthermore, the reliability of the GlcN:MurN ratio was the least dependent on measuring time point numbers. We suggest the use of multiple indicators and the adoption of multiple measuring time points for the overall methodology. [ABSTRACT FROM AUTHOR]

The available carbon (C) to phosphorus (P) ratio in the soil is regulated by extracellular hydrolases for C and P acquisition by microbes and plants. However, the stoichiometric relationship between acquiring C and P in paddy rhizosphere and bulk soils remains unclear. The objective was to explore the underlying mechanisms of C and P acquisition stoichiometry in rhizosphere and bulk soils in response to P fertilization and cellulose addition. Amendment with either cellulose or P separately caused a significant increase in the maximal velocity (Vmax) of C acquisition enzymes (β‐1,4‐glucosidase and β‐cellobiohydrolase) but decreased that of P acquisition enzymes (acid and alkaline phosphomonoesterases) in bulk soil. In contrast, lower Vmax values of C and P acquisition enzymes were observed in rhizosphere soil than in bulk soil. The co‐application of cellulose and P increased the Vmax of P acquisition enzymes in rhizosphere soil but decreased that of only alkaline phosphomonoesterase in bulk soil. Results show that P availability and labile‐C content co‐regulated the P/C acquisition ratio, and two inverse linear relationships were observed. Specifically, the P/C acquisition ratio was negatively related to both the dissolved organic C/Olsen‐P ratio and the microbial biomass C/P ratio in rhizosphere soil. However, the P/C acquisition ratio was positively related to both the dissolved organic C/Olsen‐P ratio and the microbial biomass C/P ratio in bulk soil. Overall, microbes mineralized less organic P to acquire P in paddy soil rhizosphere (i.e., containing higher labile‐C) than in bulk soil (i.e., having lower labile‐C contents). [ABSTRACT FROM AUTHOR]

Soil nitrogen (N) and phosphorus (P) contents, and soil acidification have greatly increased in grassland ecosystems due to increased industrial and agricultural activities. As major environmental and economic concerns worldwide, nutrient enrichment and soil acidification can lead to substantial changes in the diversity and structure of plant and soil communities. Although the separate effects of N and P enrichment on soil food webs have been assessed across different ecosystems, the combined effects of N and P enrichment on multiple trophic levels in soil food webs have not been studied in semiarid grasslands experiencing soil acidification. Here we conducted a short‐term N and P enrichment experiment in non‐acidified and acidified soil in a semiarid grassland on the Mongolian Plateau. We found that net primary productivity was not affected by N or P enrichment alone in either non‐acidified or acidified soil, but was increased by combined N and P enrichment in both non‐acidified and acidified soil. Nutrient enrichment decreased the biomass of most microbial groups in non‐acidified soil (the decrease tended to be greatest with combined N and P enrichment) but not in acidified soil, and did not affect most soil nematode variables in non‐acidified or acidified soil. Nutrient enrichment also changed plant and microbial community structure in non‐acidified but not in acidified soil, and had no effect on nematode community structure in non‐acidified or acidified soil. These results indicate that the responses to short‐term nutrient enrichment were weaker for higher trophic groups (nematodes) than for lower trophic groups (microorganisms) and primary producers (plants). The findings increase our understanding of the effects of nutrient enrichment on multiple trophic levels of soil food webs, and highlight that soil acidification, as an anthropogenic stressor, reduced the responses of plants and soil food webs to nutrient enrichment and weakened plant–soil interactions. [ABSTRACT FROM AUTHOR]

A free-of-dust pollution extraction method combined-homogenate and ultrasonic cavitation system, namely, homogenate-combined ultrasonic cavitation synergistic extraction (HUCSE), was proposed for the efficient extraction of flavonoids from Cinnamomum camphora leaves. Response surface methodology of Box–Behnken design was employed to optimize the HUCSE process, and the optimum operation conditions attained with an extraction yield of 7.95 ± 0.27 mg/g were ethanol concentration 76%, homogenate/ultrasonic time 25 min, solvent-to-solid ratio 22 mL/g, and ultrasonic power 240 W. A second-order kinetic mathematical methodology was performed to depict the behaviors of HUCSE and heat reflux extraction method. The results suggested that the developed HUCSE is an efficient and green method for the extraction of C. camphora flavonoids or other plant natural products, where the obvious higher parameters of extraction capacity at saturation, second-order extraction rate constant, and original extraction rate were obtained when compared to the heat reflux method. The antioxidant activity assays in vitro showed that the C. camphora flavonoids possessed strong antioxidant activity and are promising to be applied as a natural alternative antioxidant. [ABSTRACT FROM AUTHOR]

The cover image is based on the Original Article Stoichiometric theory shapes enzyme kinetics in paddy bulk soil but not in rhizosphere soil by Ge Tida et al., https://doi.org/10.1002/ldr.4141. [ABSTRACT FROM AUTHOR]

Paddy soils have experienced intensive fertilization in recent decades. However, our understanding of the effects of fertilization on the carbon (C) cycle remains incomplete. In the present study, we investigated soil organic matter (SOM) decomposition in a 60-day incubation in response to N, P, K, Ca, and S addition to nutrient-limited paddy soil at three low and three high concentrations. High levels of nutrient addition decreased CO 2 emission, q CO 2 , and microbial biomass. CO 2 emissions increased (12–17%) owing to low levels of nutrient addition, whereas it decreased (3–21%) in response to high levels of nutrient addition. Microbial biomass and nutrient turnover rates increased after low levels of nutrient addition. Positive priming effect occurs under nutrient-limited conditions owing to the stimulation of microbial biomass production after low amount of exogenous nutrient input. In contrast, high levels of nutrient addition decreased microbial biomass and net N mineralization. This high N, P, K, Ca, and S addition could satisfy the needs of microbial growth, thereby decreasing the dependency of the organisms on the original nutrients from SOM decomposition. Therefore, negative priming was observed after high-level nutrient addition. In conclusion, intensive fertilization (with N, P, K, Ca, and S) reduces SOM decomposition through increased microbial turnover in paddy soils, which might positively affect C sequestration. [ABSTRACT FROM AUTHOR]

Root exudates are a labile source of carbon (C) for microorganisms that can lead to increased CO 2 emission. Root exudates can vary in C:N stoichiometric ratio and their impact on microbially driven soil organic matter (SOM) turnover in paddy soils still remains unclear. The objective was to explore the underlying mechanisms involved in SOM decomposition due to root exudate (artificial) addition with three different C:N ratios (10, 20, and 40) during 45 days incubation. Different root exudates C:N ratios were obtained by adding mineral N and exudate components (glucose, oxalic acid, and glutamate) to paddy soil. N-only addition decreased dissolved organic C to limit CO 2 emissions, which is an indicative of C sequestration. Conversely, simulated C:N stoichiometric ratios of root exudates significantly increased both microbial activity and metabolism without altering the microbial biomass C:N ratio. However, soil available dissolved organic C to NH 4 + ratio decreased by exudates addition. The stoichiometric ratio of key C and N compound degrading enzymes activities increased only with C:N = 10 and remained unchanged with exudates C:N = 20 and 40. The q CO 2 values increased with decreasing N-containing compounds in root exudates (i.e. highest CO 2 emission was observed under C:N = 40 exudates addition). The results suggest that increasing exudates C:N ratio intensify CO 2 emission due to high microbial N demand. Overall result show that root exudates C:N ratio and soil available N co-regulate on CO 2 emission, which was controlled by microbial and potential extracellular enzyme activities. • Root exudate analogues significantly increased CO 2 emission from paddy soils. • Exudates addition increased microbial biomass and q CO 2 without altering microbial C:N ratio. • Root exudate inputs increased the accumulation of soil available NH 4 +. • N-only addition limited CO 2 emission and decreased dissolved organic C. [ABSTRACT FROM AUTHOR]

Seed dormancy is a mechanism that prevents seeds from germinating at times of the year when conditions are unfavorable, that is, when the chance of seed survival is low. Determining the seasonal dynamics of seed dormancy is important for exploring how plant regeneration is adapted to the environment. We studied the seed dormancy status of Taxus chinensis var. mairei , an endangered species in China, under simulated seasonal temperature regimes. The embryo length, embryo-to-seed (E : S) ratio, and percentage of seeds with a split seed coat increased when seeds were stratified at spring and autumn temperature regimes. The abscisic acid (ABA) content decreased during stratification at simulated seasonal temperatures, but no obvious pattern in the content of gibberellic acid (GA) and indole acetic acid (IAA) was observed. The GA-ABA and IAA-ABA ratios increased during stratification. These results suggest that T. chinensis var. mairei seeds have morphophysiological dormancy, and that the seasonal dynamics of seed dormancy break are controlled by endogenous hormones and their balances, which was confirmed by the results of a field experiment. Our study provides useful information for understanding the natural population regeneration and propagation of this threatened species., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Zhou, Xu, Wang, Yang, Lu and Zhang.)

The chemical composition of essential oil, which from the leaves of Chimonanthus grammatus obtained by hydrodistillation were analyzed by GC-MS, and their possible antibacterial properties were screened. According to the results from GC-MS analysis, fifty-three components comprising 99.99% of the essential oil were identified. The major components of essential oil were 3-(4, 8-dimethyl-3,7-nonadienyl)(E) -furan (13.1%), bornyl acetate (12.66%), and 6,6-dimethyl-3-methylene-bicyclo[3.1.1] heptane (7.06%), etc. Antibacterial activity of essential oil was employed by two complementary test systems of disc diffusion and MIC/ MBC tests, which showed obviously antibacterial activity against all of the tested bacteria.