Decomposition of soil organic matter (SOM) is sensitive to vegetation and climate change. Here, we investigated the influence of changes in forest types on the mineralization of soil carbon (C) and nitrogen (N), and their temperature sensitivity (Q₁₀) and coupling relationships by using a laboratory soil incubation experiments. We sampled soils from four forest types, namely, a primary Quercus liaotungensis forest (QL), Larix principis-rupprechtii plantation (LP), Pinus tabulaeformis plantation (PT), and secondary shrub forest (SS) in temperate northern China. The results showed that soil C and N mineralization differed significantly among forest types. Soil C and N mineralization were closely coupled in all plots, and C:N ratios of mineralized SOM ranged from 2.54 to 4.12. Forest type significantly influenced the Q₁₀ values of soil C and N mineralization. The activation energy (E_a) of soil C and N mineralization was negatively related to the SOM quality index in all forest types. The reverse relationships suggested that the carbon quality-temperature (CQT) hypothesis was simultaneously applicable to soil C and N mineralization. Our findings show that the coupled relationships of soil C and N mineralization can be affected by vegetation change.

Although it is well-documented that invasion of invasive plants is promoted with allelopathic effects by inhibiting the growth and phenotypic performance of native plants, little is known conversely. In this study, the allelopathy effects of a native plant, Humulus scandens (Lour.) Merr., on a typical invasive species Alternanthera philoxeroides (Mart.) Griseb., was investigated by exposing A. philoxeroides seedlings to three chemical solvent extracts (i.e., petroleum ether extract (PE), ethyl acetate extract (EE), and n-butanol extract (NE) of H. scandens root (HR). The three chemical extracts inhibited the growth, stem length, node number, leaf number, leaf area, and root number, and increased malondialdehyde (MDA) content of A. philoxeroides seedlings, which indicated that the extracts inhibited the plant growth by damaging the membrane system of leaves. And the synthetical effect of allelopathy (SE) index indicated that EE had the greatest inhibition on the growth of A. philoxeroides. Fifty compounds were identified from the three extracts of HR using GC–MS analysis, among which 5 compounds (dibutyl phthalate, stigmasta-3,5-diene, 2,6-Di-tert-butylphenol campesterol, and neophytadiene) were identified from H. scandens root extracts for the first time. And n-hexadecanoic acid exists in all three extracts. The findings of the present study provide a novel method to potentially control the invasion of A. philoxeroides. However, field monitoring under natural conditions would be necessary to confirm in practice the results obtained with the bioassays.

The application of carbon-based nanomaterials (CBNMs) in plant science and agriculture is a very recent development. Many studies have been conducted to understand the interactions between CBNMs and plant responses, but how fullerol regulates wheat subjected to drought stress is still unclear. In this study, seeds of two wheat cultivars (CW131 and BM1) were pre-treated with different concentrations of fullerol to investigate seed germination and drought tolerance. Our results indicate that the application of fullerol at certain concentrations (25–200 mg L⁻¹) significantly promoted seed germination in two wheat cultivars under drought stress; the most significant effective concentration was 50 mg L⁻¹, which increased the final germination percentage by 13.7% and 9.7% compared to drought stress alone, respectively. Wheat plants exposed to drought stress induced a significant decrease in plant height and root growth, while reactive oxygen species (ROS) and malondialdehyde (MDA) contents increased significantly. Interestingly, wheat seedlings of both cultivars grown from 50 and 100 mg L⁻¹ fullerol-treated seeds were promoted in seedling growth under water stress, which was associated with lower ROS and MDA contents, as well as higher antioxidant enzyme activities. In addition, modern cultivars (CW131) had better drought adaptation than old cultivars (BM1) did, while the effect of fullerol on wheat had no significant difference between the two cultivars. The study demonstrated the possibility of improving seed germination, seedling growth and antioxidant enzyme activities by using appropriate concentrations of fullerol under drought stress. The results are significant for understanding the application of fullerol in agriculture under stressful conditions.

Synthetic microbial communities (SynCom) contribute to mitigating soil-borne crop diseases while enhancing both crop quality and yield. However, relatively little research has been done on the intricate regulatory mechanisms of SynCom on the suppression of soil-borne diseases. We aimed to elucidate the dynamic regulatory mechanisms and legacy effects of a SynCom on the composition of soil functional microorganisms, soil multifunctionality and crucial functions, and the suppression of soil-borne diseases. We conducted an extensive series of experiments to assess the effect of a SynCom on the changes in the rhizosphere functional microorganisms and soil functions (e.g., multifunctionality, functionality of C, N, and P cycling) across six successive generations of strawberry in consecutive monoculture soils by employing amplicon metagenomics and transcriptome sequencing. Our results showed that the SynCom increased the aboveground fresh biomass of strawberry by 31-70.3% and the fruit biomass by 171.39-280.71%, and decreased the Fusarium oxysporum abundance by 17.91-49.51% compared to the consecutive monoculture. The SynCom significantly enhanced the soil C cycling and P cycling function, and soil multifunctionality (SMF). SynCom treatment significantly increased the Shannon diversity index and relative abundances of potentially beneficial bacteria and consumer protistan communities, while exerted a significant inhibitory effect on the Shannon diversity index and relative abundances of fungal pathogen. SEM result showed that SynCom significantly affected SMF by influencing soil nutrients, the abundance and diversity of functional microbial community. Our result also showed that the SynCom established the positive legacy effects on the abundance of rhizosphere soil beneficial bacteria, strawberry biomass and plant disease resistance-associated pathways (phenylpropanoid biosynthesis pathway, alpha-linolenic acid metabolism pathway), and negative effect on the abundance of pathogenic F. oxysporum under the 7th generation of strawberry cropping. Collectively, our study demonstrated the effectiveness of employing SynCom in mitigating soil-borne Fusarium oxysporum diseases by enhancing soil functional microbial abundance and soil multifunctionality.