With global climate change, atmospheric nitrogen deposition is intensifying. However, the specific impact of nitrogen deposition on forest ecosystem productivity remains unclear. Additionally, due to the differences in the origin of planted and natural forests, it is not clear whether the effects of nitrogen deposition on different types of forest functions are consistent. This study utilizes data from 384 planted forests and 541 natural forests in China, collected through field surveys and literature research from 2005 to 2020, to explore the specific effects of nitrogen deposition on the productivity of natural and planted forests. The results show that the levels of six forms of nitrogen deposition (gaseous NO2, HNO3, NH3, and particulate NH4+, NO3- as well as total dry nitrogen deposition (TN)) are significantly higher in planted forests than in natural forests (P < 0.001). With increasing nitrogen deposition, the NPP (Net Primary Productivity) of planted forests significantly linear increased, while that of natural forests significantly decreased. Compared to natural forests, nitrogen deposition contributes more to the spatial variability of NPP in planted forests. Under the background of nitrogen deposition, forest climate factors (MAP, MAT) and soil phosphorus content have a positive effect on the NPP of natural and planted forests, while soil pH and soil nitrogen content have a negative effect. MAT is the dominant factor for the spatiotemporal variability of NPP in natural forests, while community functional traits (Trait PC1) are the dominant factor for the spatial variability of NPP in planted forests. Nitrogen deposition can not only directly affect the NPP of natural and planted forests but also indirectly through its impact on plant functional traits, forest climate, and soil nutrient factors. Our findings reveal the specific impacts of nitrogen deposition on the productivity of natural and planted forests, providing data support for effective forest management.

Studying key leaf functional traits is crucial for understanding plant resource utilization strategies and growth. To explore the patterns and driving factors of key leaf functional traits in forests along elevational gradients under global change, we collected survey data from 697 forests across China from 2008 to 2020. This study examined the elevational patterns of Specific Leaf Area (SLA, m²/kg), Leaf Dry Matter Content (LDMC, g/g), Leaf Nitrogen (LN, mg/g), and Leaf Phosphorus (LP, mg/g), and their responses to climate, soil nutrients, and stand factors. The results showed distinct differences in these key leaf traits at different elevational gradients. Generally, as elevation increased, SLA decreased, while LDMC significantly increased (P < 0.001), and LN first increase and then decreased (P < 0.001). The direct influence of elevation on the spatial variation of key leaf traits was greater than its indirect effects (through environmental and stand factors). The elevational patterns of leaf traits related to resource utilization strategies (SLA and LDMC) were mainly influenced by climate (temperature and precipitation) and soil nutrient factors, showing opposite trends in response to environmental changes. The patterns of leaf nutrient traits (LN and LP) along elevational gradients were primarily influenced by climatic factors, with LN exhibiting greater environmental plasticity. Compared to other stand factors, forest age predominantly influenced the spatial variation of key leaf traits, especially SLA. These findings have significant theoretical implications for revealing how plants adapt to global change.

Specific leaf area (SLA) and leaf dry matter content (LDMC) are key leaf functional traits commonly used to reflect tree resource utilization strategies and predict forest ecosystem responses to environmental changes. Previous research on tree resource utilization strategies (SLA and LDMC) primarily focused on the species level within limited spatial scales, making it crucial to quantify the spatial variability and driving factors of these strategies. Whether there are discrepancies in resource utilization strategies between trees in planted and natural forests, and the dominant factors and mechanisms influencing them, remain unclear. This study, based on field surveys and the literature from 2008 to 2020 covering 263 planted and 434 natural forests in China, using generalized additive models (GAMs) and structural equation models (SEMs), analyzes the spatial differences and dominant factors in tree resource utilization strategies between planted and natural forests. The results show that the SLA of planted forests is significantly higher than that of natural forests (p < 0.01), and LDMC is significantly lower (p < 0.0001), indicating a “faster investment–return” resource utilization strategy. As the mean annual high temperature (MAHT) and mean annual precipitation (MAP) steadily rise, trees have adapted their resource utilization strategies, transitioning from a “conservative” survival tactic to a “rapid investment–return” model. Compared to natural forests, planted forest trees exhibit stronger environmental plasticity and greater variability with forest age in their resource utilization strategies. Overall, forest age is the dominant factor influencing resource utilization strategies in both planted and natural forests, having a far greater direct impact than climatic factors (temperature, precipitation, and sunlight) and soil nutrient factors. Additionally, as forest age increases, both planted and natural forests show an increase in SLA and a decrease in LDMC, indicating a gradual shift towards more efficient resource utilization strategies.

Specific leaf area (SLA) and leaf dry matter content (LDMC) are key leaf functional traits often used to reflect plant resource utilization strategies and predict plant responses to environmental changes. In general, grassland plants at different elevations exhibit varying survival strategies. However, it remains unclear how grassland plants adapt to changes in elevation and their driving factors. To address this issue, we utilized SLA and LDMC data of grassland plants from 223 study sites at different elevations in China, along with climate and soil data, to investigate variations in resource utilization strategies of grassland plants along different elevational gradients and their dominant influencing factors employing linear mixed-effects models, variance partitioning method, piecewise Structural Equation Modeling, etc. The results show that with increasing elevation, SLA significantly decreases, and LDMC significantly increases (P < 0.001). This indicates different resource utilization strategies of grassland plants across elevation gradients, transitioning from a “faster investment-return” at lower elevations to a “slower investment-return” at higher elevations. Across different elevation gradients, climatic factors are the main factors affecting grassland plant resource utilization strategies, with soil nutrient factors also playing a non-negligible coordinating role. Among these, mean annual precipitation and hottest month mean temperature are key climatic factors influencing SLA of grassland plants, explaining 28.94% and 23.88% of SLA variation, respectively. The key factors affecting LDMC of grassland plants are mainly hottest month mean temperature and soil phosphorus content, with relative importance of 24.24% and 20.27%, respectively. Additionally, the direct effect of elevation on grassland plant resource utilization strategies is greater than its indirect effect (through influencing climatic and soil nutrient factors). These findings emphasize the substantive impact of elevation on grassland plant resource utilization strategies and have important ecological value for grassland management and protection under global change.

Compared to planted forest ecosystems (PFE), natural forest ecosystems (NFE) generally have a longer history and theoretically have stronger environmental adaptability. Changes in net primary productivity (NPP) due to global change have been studied for many forest types, yet the underlying mechanism remain poorly understood. Using 926 forest plots (including both PFE and NFE) established between 2005 and 2020 in China, we found that NPP exhibited stronger climate and soil nutrient responses, with greater environmental plasticity, in PFE versus NFE. Several functional traits (e.g., leaf area, leaf nitrogen and phosphorus content) differed between NFE and PFE, but only weakly predicted spatial variation in NPP, as compared to the environmental factors. Overall, NPP in both NFE and PFE showed consistent responses to climate and soil nutrient changes. These environmental responses were weaker in coniferous forests than broadleaved forests. Direct effects of climatic factors on NPP were stronger than indirect effects. Overall, the effects of functional traits on NPP were mediated by climatic and edaphic factors. These findings provide guidance for more reliable predictions of NPP and succession in NFE and PFE in the context of global warming.

The allocation of biomass reflects a plant's resource utilization strategy and is significantly influenced by climatic factors. However, it remains unclear how climate factors affect the aboveground and belowground biomass allocation patterns on macro scales. To address this, a study was conducted using aboveground and belowground biomass data for 486 species across 294 sites in China, investigating the effects of climate change on biomass allocation patterns. The results show that the proportion of belowground biomass in the total biomass (BGBP) or root-to-shoot ratio (R/S) in the northwest region of China is significantly higher than that in the southeast region. Significant differences (p < 0.05) were found in BGBP or R/S among different types of plants (trees, shrubs, and herbs plants), with values for herb plants being significantly higher than shrubs and tree species. On macro scales, precipitation and soil nutrient factors (i.e., soil nitrogen and phosphorus content) are positively correlated with BGBP or R/S, while temperature and functional traits are negatively correlated. Climate factors contribute more to driving plant biomass allocation strategies than soil and functional trait factors. Climate factors determine BGBP by changing other functional traits of plants. However, climate factors influence R/S mainly by affecting the availability of soil nutrients. The results quantify the productivity and carbon sequestration capacity of terrestrial ecosystems and provide important theoretical guidance for the management of forests, shrubs, and herbaceous plants.

Biomass in forests sequesters substantial amounts of carbon; although the contribution of aboveground biomass has been extensively studied, the contribution of belowground biomass remains understudied. Investigating the forest biomass allocation is crucial for understanding the impacts of global change on carbon allocation and cycling. Moreover, the question of how climate factors affect biomass allocation in natural and planted forests remains unresolved. Here, we addressed this question by collecting data from 384 planted forests and 541 natural forests in China. We evaluated the direct and indirect effects of climate factors on the belowground biomass proportion (BGBP). The average BGBP was 31.09% in natural forests and was significantly higher (38.75%) in planted forests. Furthermore, we observed a significant decrease in BGBP with increasing temperature and precipitation. Climate factors, particularly those affecting soil factors, such as pH, strongly affected the BGBP in natural and planted forests. Based on our results, we propose that future studies should consider the effects of forest type (natural or planted) and soil factors on BGBP.

The allocation of plant biomass above and below ground reflects their strategic resource utilization, crucial for understanding terrestrial carbon flux dynamics. In our comprehensive study, we analyzed biomass distribution patterns in 580 broadleaved and 345 coniferous forests across China from 2005 to 2020, aiming to discern spatial patterns and key drivers of belowground biomass proportion (BGBP) in these ecosystems. Our research revealed a consistent trend: BGBP decreases from northwest to southeast in both forest types. Importantly, coniferous forests exhibited significantly higher BGBP compared to broadleaved forests (p < 0.001). While precipitation and soil nutrients primarily influenced biomass allocation in broadleaved forests, temperature and soil composition played a pivotal role in coniferous forests. Surprisingly, leaf traits had a negligible impact on BGBP (p > 0.05). Climatic factors, such as temperature and rainfall, influenced biomass partitioning in both strata by altering soil nutrients, particularly soil pH. These findings provide valuable insights into understanding carbon sequestration dynamics in forest ecosystems and improving predictions of the future trajectory of this critical carbon cycle component.

Plant functional traits are a representation of plant resource utilization strategies. Plants with higher specific leaf area (SLA) and lower leaf dry matter content (LDMC) exhibit faster investment-return resource utilization strategies. However, the distribution patterns and driving factors of plant resource utilization strategies at the macroscale are rarely studied. We investigated the relative importance of climatic and soil factors in shaping plant resource utilization strategies at different life forms in forests using data collected from 926 plots across 163 forests in China. SLA and LDMC of plants at different life forms (i.e., trees, shrubs, and herbs) differ significantly. Resource utilization strategies show significant geographical differences, with vegetation in the western arid regions adopting a slower investment-return survival strategy and vegetation in warmer and wetter areas adopting a faster investment-return survival strategy. SLA decreases significantly with increased temperature and reduced rainfall, and vegetation growing in these conditions exhibits conservative resource utilization. Mean annual precipitation (MAP) is a key climatic factor that controls the resource utilization strategies of plants at the macroscale. Plants use resources more conservatively as soil pH increases. The influence of climate and soil factors is coupled to determine the resource utilization strategies of plants occupying different life forms at the macroscale, but the relative contribution of each varies across life forms. Our findings provide a theoretical framework for understanding the potential impact of increasing global temperatures on plant resource utilization.

To investigate whether the kanamycin resistant(KanR) gene in mammary-specific expression vector p215C3LYZ for treating bovine mastitis could express active protein in mammalian cells under the control of its own promoter,KanR gene was amplified by PCR using mammary-specific expression vector p215C3LYZ as the template and subcloned into prokaryotic expression vector pQE-31.After transformation and cultivation on Kan-containing agar plates,Kan-resistant E.coli colonies were obtained and an expected recombinant protein was expressed after IPTG induction.After separation on SDS-PAGE,the protein band was excised and specific antiserum was obtained by immunization of mice for 6 times.The specificity of the antiserum was confirmed using Western blotting.The prokaryotic expression vector pQE-Kan and eukaryotic expression vector p215C3LYZ,both of which contained KanR gene,were transfected into COS-1 cells and the supernatants were collected after cultivation in antibiotic-free medium,DH5α E.coli were inoculated into the supernatants in the absence or presence of Kan and the OD600 values were detected after 24h cultivation.The results showed that growth of the indicator bacterium was inhibited significantly in the presence of Kan,indicating that the Kan resistant protein was not expressed in the supernatants of the vector-transfected cells.Western blotting of the cell lysates confirmed that Kan resistant protein was not expressed in the vector-transfected cells.In addition,no Kan resistant protein was detected in concentrated milk samples from cows after intramammary injection with vector p215C3LYZ.These experimental data demonstrate that the promoter of KanR gene is inactive in mammalian cells,providing additional safety evidence using the p215C3LYZ vector for treating bovine mastitis.

Twenty one strains of ThyA-E.coli DH5α were isolated using the selection medium containing thymine deoxyriboside and trimethoprim.The thyA genes were amplified from the wild type and 4 mutant E.coli by PCR and sequencing.Compared with the wild-type thyA,the mutant 6 had a G→A transition at the position of nucleotide 92,resulting in Gly31Asp substitution,and mutants 4,7 and 13 had a same 6 bp deletion from nucleotide 73,resulting in Gly25 and Thr26 deletions.The thyA gene of Salmo-nella typhimurium was amplified by PCR and submitted to sequence analysis,which showed an 86% homology to that of the wild-type E.coli at nucleotide and amino acid sequence levels.The thyA gene was used as the selection marker for construction of eukaryotic expression vector pDTALYZ and the chromosome-plasmid lethal-balanced system was generated using ThyA-E.coli as the host cell.Under the same conditions,the chromosome-plasmid lethal-balanced system had higher transformation efficiency and similar growth rate to the pcDNAKLYZ transforming wild-type E.coli DH5α using kanamycin resistance gene as the selection marker.During high density fermentation,the two systems had similar bacterial growth rates,plasmid loss rates of 25% and 10%,wet bacterial weights of 57.68 g/L and 51.00 g/L,and plasmid yields of 134.9 mg/L and 135.0 mg/L,respectively.