To reveal the effects of different land-use types on soil enzyme activities, soil samples were collected from 0–10, 10–20 and 20–30 cm soil layers to compare and analyze soil β-glucosidase (BG), urease (URE), protease (PROT) and catalase (CAT) activities in farmland (FL), abandoned land (AL) and three plantation forests: Platycladus orientalis (L.) Franco (PO), Robinia pseudoacacia L. (RP) and Quercus variabilis Bl. (QV) in the rocky mountainous region of North China. The results showed that the soil enzyme activities varied significantly under different land-use types, and the interannual mean values of FL and PO were remarkably higher than those of other land uses in the 0–30 cm soil layer, in which the soil BG and URE activities of FL were 22% and 12% higher than those of AL, and 428% and 179% higher than those of QV, respectively; the soil PROT and CAT activities of PO were 66% and 23% higher than those of AL, and 479% and 113% higher than those of QV, respectively. Soil BG, URE and PROT activities were all higher in June and lower in December, while soil CAT activity was slightly lower in June. The soil enzymatic activities all showed a notable decrease with the depth of the soil layer. Soil BG, URE, PROT and CAT activities were remarkably (p < 0.01) or significantly (p < 0.05) positively correlated with available nitrogen, available phosphorus, available potassium, dissolved organic carbon (DOC), NO₃⁻-N, soil organic carbon, water content, clay and silt volume fraction, and significantly negatively correlated with sand volume fraction. Soil DOC and pH were important factors influencing soil enzymatic activity, implying that changes in soil enzymatic activity under different land-use types may be the result of a combination of temperature, moisture and plant type. In conclusion, PO plantations are conducive to improving the physicochemical and biological properties of soil and enhance soil fertility, which is a reasonable land-use method to achieve sustainable development in the rocky mountainous region of North China.

Climate warming has led to more frequent soil freeze–thaw (FT) events in high-latitude and high-altitude regions, leading to significant pulse releases of greenhouse gasses (GHGs) such as nitrous oxide (N₂O) and carbon dioxide (CO₂) into the atmosphere. These pulse emissions exhibit unpredictable spatiotemporal variability, which are influenced by soil type, soil moisture and FT temperature. This study employed controlled laboratory experiments to investigate the effects of varying FT intensities (−10 °C/10 °C, −5 °C/5 °C, and a control at 0 °C/0 °C) and soil moisture levels (30%, 60%, and 90% water-filled pore space, WFPS) on the dynamics of soil N₂O and CO₂ emissions (measured daily), and the availability of carbon and nitrogen, microbial biomass, and enzyme activities (measured weekly) in the soils collected from two forest stands in the Changbai mountains of northeast China, a broadleaf and Korean pine (Pinus koraiensis Sieb. et Zucc.) mixed forest (BKPF) and an adjacent secondary white birch (Betula platyphylla Suk.) forest (WBF), where FT events frequently occur. Our findings reveal that a high FT intensity (−10 °C/10 °C) significantly increased N₂O and CO₂ emissions from BKPF and WBF soils. With increasing soil moisture, soil CO₂ emissions peaked at 60% WFPS, while soil N₂O emissions were the highest at 90% WFPS. Notably, pulse emissions of N₂O were particularly intense under a high FT intensity and high moisture (i.e., 90% WFPS) in WBF soils, persisting for nearly 8 days during FT cycles. The emissions of N₂O and CO₂ under varying FT and moisture conditions are intricately regulated by soil substrate dynamics, including dissolved organic carbon, nitrogen mineralization, and nitrate concentrations. The results improve the understanding of the high variability of soil GHG emissions during the FT process and its underlying mechanisms, which are inadequately considered in current ecological and land surface process models. Consequently, it would contribute valuable insights into the interaction between soil GHG emissions and climate change in high-latitude and high-altitude zones.

The ethylene response factor (ERF) family is a prominent plant-specific transcription factor family, which plays a crucial role in modulating plant growth and stress tolerance. In this study, a total of 210 ERFs were identified in Populus trichocarpa, comprising 29 AP2 (APETALA2) subfamily members, 176 ERF subfamily members, and 5 RAV (related to ABI3/VP1) subfamily members. The duplication events of the PtERF family members exclusively occurred within the subfamilies. A total of 168 duplication pairs were found among 161 PtERF genes, and all of them were fragment duplications. Gene structure analysis revealed that most ERF subfamily members only had one exon without introns, the AP2 subfamily members had six or more introns and exons, and RAV subfamily members lacked introns except for PtERF102. Considerable cis-acting elements associated with plant growth and development, stress response, hormone response, and light response were detected in the promoters of PtERF genes. The expression levels of PtERFs were highest in roots across tissues and in winter among seasons. Furthermore, the nitrate and urea stimulated the expression of PtERF genes. The co-expression network analysis based on PtERFs indicated their potential roles in hormone signaling, acyltransferase activity, and response to chemicals. This study provides novel insights into investigating the role of PtERFs in environmental stress in poplar species.

Rosemary (Salvia rosmarinus) is a world-famous plant frequently subjected to various environmental stresses. Heat Shock Transcription Factor (HSF) has been shown to be essential for plant growth and for resistance to environmental stresses. This study utilized bioinformatics techniques to identify the SrHSF gene family in the rosemary genome. A total of 49 SrHSFs were detected, unevenly distributed across 12 chromosomes. The SrHSF genes were classifiable into 3 subfamilies and contained in 14 subgroups. They were relatively conserved during the evolutionary process based on gene structure and conserved motif analysis. There were 22 kinds of cis-acting elements in the promoter regions of SrHSF genes, mostly related to hormones, stress, growth, and development. The interactions among 16 highly conserved SrHSF proteins were also identified. Gene collinearity analysis showed that 51 segmental duplication events were undergone among 41 SrHSF genes. Ka/Ks ratios were all less than 1, suggesting a purifying selection of SrHSF homologous genes. The expression pattern of SrHSF genes revealed that the majority of them are highly expressed in the secondary stems. After 0.1% MeJA treatment, SrHSF36 and SrHSF11 showed a significant upregulation in leaves. This research provides valuable insights into the functions and regulatory mechanisms of the SrHSF gene family.

The oligopeptide transporter (OPT) family belongs to a type of proton-coupled symporter and functions in the transport of metal ions, glutathione, phytoche