Stochastic process drives the dissimilarity in biodiversity patterns between Pinus kwangtungensis coniferous forest and evergreen deciduous broad-leaved mixed forest in karst area.

Pinus kwangtungensis is an endangered evergreen conifer tree species, and its in situ conservation has been considered one of the most critical issues. However, relative protection is limited by the lack of understanding of its community structure and underlying assembly processes. To study how the species diversity and assembly processes of Pinus kwangtungensis coniferous forest (CF) differed with regional climax community, this study established a series forest dynamic plots both in CF and evergreen deciduous broadleaved mixed forest (EDBM). By performing comparison analysis and PER-SIMPER approaches, we quantified the differences in species diversity and community assembly rules. The results showed that the species α-diversity of CF differed greatly from the EDBM both in species richness and evenness. In addition, the stochastic process acted a more important role in determining species composition, indicating the uncertainty in presence of species. The soil phosphorus and changeable calcium content were the main factors driving the differences in biodiversity, which the importance of soil nutrient factors in driving species composition. Our study highlighted that we should consider the community structure and ecological process when conducting conservation of Pinus kwangtungensis.

Deciphering the Role of SVP-Like Genes and Their Key Regulation Networks During Reproductive Cone Development in Pinus tabuliformis.

Reproductive development plays an essential role in the perpetuation of genetic material and environmental adaptation. In angiosperms, the Short Vegetative Phase (SVP) serves as a flowering repressor, influencing the development of floral organs. In this study, heterologous transformation of Arabidopsis thaliana with SVP-like genes (PtSVL1 and PtSVL2) derived from Pinus tabuliformis significantly impacted stamen formation and pollen fertility, without altering flowering time. Gene co-expression networks revealed that SVP-like and SOC1-like genes function as key coregulatory transcription factors during the initial stages of cone development in P. tabuliformis. Interestingly, the regulatory module of SOC1 regulated by SVP in angiosperms is absent in conifers and conifer SVP-like exercises its function in a form that is physically bound to SOC1-like. Furthermore, combining the yeast one-hybrid scanning with co-expression network analysis, revealed that SPLs and TPSs were the principal downstream target genes of PtSVL1. Notably, the PtSPL16 promoter is positively regulated by PtSVL1, and overexpression of PtSPL16 results in delayed flowering in Arabidopsis, suggesting that the PtSVL1-PtSPL16 module plays a crucial role in regulating reproductive development in conifers. Collectively, these findings enhance our understanding of the roles of SVP-like genes in conifers and the key regulatory networks centred on PtSVL1 during reproductive cone development.

Methyl jasmonate induced tolerance effect of Pinus koraiensis to Bursaphelenchus xylophilus.

BACKGROUND: Methyl jasmonate (MeJA) can affect the balance of hormones and regulate the disease resistance of plants. Exploring the application and mechanism of MeJA in inducing the tolerance of Pinus koraiensis to pine wood nematode (PWN) infection is of great significance for developing new strategies for pine wilt disease control. RESULTS: Different concentrations (0.1, 1, 5 and 10 mm) of MeJA treatment groups showed differences in relative tolerance index and relative anti-nematode index of P. koraiensis seedlings to PWN infection. The treatment of 5 mm MeJA solution induced the best tolerance effect, followed by the 1 mm MeJA solution. Transcriptome analysis indicated that many plant defense-related genes upregulated after treatment with 1, 5 and 10 mm MeJA solutions. Among them, genes such as jasmonate ZIM domain-containing protein, phenylalanine ammonia-lyase and peroxidase also continuously upregulated after PWN infection. Metabolome analysis indicated that jasmonic acid (JA) was significantly increased at 7 days postinoculation with PWN, and after treatment with both 1 and 5 mm MeJA solutions. Integrated analysis of transcriptome and metabolome indicated that differences in JA accumulation might lead to ubiquitin-mediated proteolysis, and expression changes in trans-caffeic acid and trans-cinnamic acid-related genes, leading to the abundance differences of these two metabolisms and the formation of multiple lignin and glucosides. CONCLUSIONS: MeJA treatment could activate the expression of defense-related genes that correlated with JA, regulate the abundance of defense-related secondary metabolites, and improve the tolerance of P. koraiensis seedlings to PWN infection. © 2024 Society of Chemical Industry.

HcZnT2 is a highly mycorrhiza-induced zinc transporter from Hebeloma cylindrosporum in association with pine.

Zinc (Zn) shortage is a common micronutrient deficiency affecting plants worldwide, while Zn toxicity may occur when this metal is in excess. Ectomycorrhizal (ECM) fungi are known to be able to modulate the transfer of macro- and microelements, among them Zn, to the plant. However, the underlying mechanisms are not well understood. We identified the HcZnT2 gene from the ECM fungus Hebeloma cylindrosporum, encoding a member of the Cation Diffusion Facilitator (CDF) family including Zn transporters, and analyzed its transcriptional regulation, the transport function by yeast complementation experiments, and its subcellular localization using a GFP fusion protein in yeast. HcZnT2 is highly induced during mycorrhization of Pinus pinaster, and upregulated in presence of the host plant root even without any direct contact. However, HcZnT2 is repressed by Zn excess conditions. By functional expression in yeast, our results strongly support the ability of HcZnT2 to transport Zn and, to a lesser extent, manganese. HcZnT2 localization was associated with the endoplasmic reticulum of yeast. Mycorrhizal gene activation at low external Zn suggests that the Zn transporter HcZnT2 might be important for the early establishment of the ECM symbiosis during Zn deficiency, rather than under Zn excess. HcZnT2 arises as an extremely remarkable candidate playing a key role in Zn homeostasis and regulation in ectomycorrhiza.

Effects of exogenous calcium additions on the ecological stoichiometric characteristics of various organs and soil nutrients and their internal stability in Pinus tabuliformis.

Introduction: Pinus tabuliformis as a crucial afforestation species in semi-arid regions, faces issues such as the reduction of plantations. Calcium plays a significant role in alleviating drought stress and promoting nutrient uptake in plants. Methods: Utilizing a pot experiment approach, seedlings were treated with exogenous calcium at five concentrations (0, 50, 100, 200, and 400 mg•kg-1). The nutrient content of the plants and soil was measured, and their ecological stoichiometric characteristics and internal stability were analyzed. This was followed by a series of related studies. Results: As the concentration of calcium increases, the contents of carbon, nitrogen, phosphorus, and potassium in various organs and the whole plant exhibit a trend of first increasing and then decreasing, peaking at calcium treatment of 50-100 mg•kg-1. Concurrently, the calcium concentration in plant organs and the entire plant gradually increases with the availability of calcium in the soil. The addition of exogenous calcium has a certain impact on the ecological stoichiometric ratios (C:N, C:P, N:P) of Pinus tabuliformis seedlings' leaves, stems, roots, and the whole plant, exhibiting distinct variation characteristics. At calcium concentrations of 50-100 mg•kg-1, the ratios of C:N and C:P are relatively lower. Under calcium concentrations of 0, 50, and 100 mg•kg-1, soil calcium shows a positive correlation with the total carbon (TC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), and calcium contents in leaves, stems, roots, and the entire plant. However, at calcium concentrations of 200 and 400 mg•kg-1, soil calcium exhibits a significant positive correlation with the calcium content in leaves, stems, roots, and the entire plant, and a significant negative correlation with the total phosphorus, total nitrogen, total phosphorus, and total potassium contents. After the addition of exogenous calcium at different concentrations, most stoichiometric indices of various organs of Pinus tabuliformis seedlings demonstrate strong balance. Discussion: Calcium, as an essential structural component and second messenger, regulates the nutrient uptake and utilization in plants, influencing the stoichiometry. However, both low and high concentrations of calcium can be detrimental to plant growth by disrupting nutrient metabolism and internal structures. Consequently, there exists an optimal calcium concentration for nutrient absorption.

Comparative Stem Transcriptome Analysis Reveals Pathways Associated with Drought Tolerance in Maritime Pine Grafts.

The maritime pine (Pinus pinaster Ait.) is a highly valuable Mediterranean conifer. However, recurrent drought events threaten its propagation and conservation. P. pinaster populations exhibit remarkable differences in drought tolerance. To explore these differences, we analyzed stem transcriptional profiles of grafts combining genotypes with contrasting drought responses under well-watered and water-stress regimes. Our analysis underscored that P. pinaster drought tolerance is mainly associated with constitutively expressed genes, which vary based on genotype provenance. However, we identified key genes encoding proteins involved in water stress response, abscisic acid signaling, and growth control including a PHD chromatin regulator, a histone deubiquitinase, the ABI5-binding protein 3, and transcription factors from Myb-related, DOF NAC and LHY families. Additionally, we identified that drought-tolerant rootstock could enhance the drought tolerance of sensitive scions by regulating the accumulation of transcripts involved in carbon mobilization, osmolyte biosynthesis, flavonoid and terpenoid metabolism, and reactive oxygen species scavenging. These included genes encoding galactinol synthase, CBL-interacting serine/threonine protein kinase 5, BEL1-like homeodomain protein, dihydroflavonol 4-reductase, and 1-deoxy-D-xylulose-5-phosphate. Our results revealed several hub genes that could help us to understand the molecular and physiological response to drought of conifers. Based on all the above, grafting with selected drought-tolerant rootstocks is a promising method for propagating elite recalcitrant conifer species, such as P. pinaster.

The Impact of Pinus koraiensis Leaf Extract Consumption on Postprandial ApoB100 and Lipid Metabolism: A Randomized, Double-Blind, Placebo-Controlled Trial in Healthy Participants Subjected to an Oral High-Fat Challenge.

Pinus koraiensis (PK) leaf extract, derived from Korean pine byproducts, holds promise for alleviating postprandial hyperlipidemia. In this study, we investigated the potential of PK leaf extract for modulating postprandial hyperlipidemia in adults with normal or borderline fasting triglyceride levels. In a randomized, double-blind, parallel design, 70 subjects were randomly assigned to either the placebo or PK group for 4 weeks. After 4 weeks of consuming PK leaf extract, the results indicated a trend toward decreased serum apolipoprotein B-100 (ApoB100) levels 2 h after a high-fat challenge. Furthermore, significant improvements were observed in the incremental area under the curve (iAUC) at 0-4 h and 2-4 h compared to baseline, particularly among individuals with a higher body weight (>61.35 kg) and daily caloric intake (>1276.5 kcal). Based on these findings, PK leaf extract may have beneficial effects on postprandial lipoprotein metabolism, especially among individuals with a relatively high body weight and caloric intake.

Comparative analysis of element and hormone content in zygotic embryos of Pinus elliottii and P. elliottii × P. caribaea.

Somatic embryogenesis is a crucial method for achieving clonal forestry in conifers. Understanding the development of zygotic embryos is essential not only for enhancing the efficiency and quality of somatic embryogenesis, but also for advancing forestry breeding programs. This study investigated dynamic changes of element and hormone contents during ZE development of Pinus elliottii and its hybrid P. elliottii × P. caribaea. Significant differences in embryo development speed among different clones were observed. Elemental analysis was conducted using inductively coupled plasma mass spectrometry (ICP-MS) and identified 68 elements, including major, minor, and beneficial elements. In both species, the contents of potassium (K), calcium (Ca), iron (Fe), boron (B) and five beneficial elements decreased during early ZE development, while phosphorus (P) and copper (Cu) increased. Significantly higher levels of K, Ca and Fe at the initial stage, and sulfur (S) and nickel (Ni) decreased at later stages were detected in P. elliottii than in the hybrid. For the other elements, except for very few significant differences at certain stages, most differences between the two species did not reach a significant level. The contents of endogenous hormones were determined and different accumulation patterns were detected in most hormones between the two species, except abscisic acid (ABA) which simultaneously decreased with developments by stage 8. Significant differences were found in indole-3-acetic acid (IAA) contents at most stages between species, while higher levels of total cytokinin (CK) at each stage were detected in the hybrid in comparison with those in P. elliottii. As a result, lower IAA to CK ratios in the hybrid than in P. elliottii. Methyl jasmonate (JA-me) and gibberellin A3 (GA3) contents showed a similar pattern and exhibited an M-shaped fluctuation in the hybrid. Furthermore, JA-me, GA3, gibberellin A4 (GA4) and brassinolide (BR) showed significantly higher levels in the hybrid than in P. elliottii. K-means clustering and correlation analyses were used to explore relationships between elements and hormones during embryo development, revealing complex interplay in both species. These data indicate different requirement in element and hormone contents for embryogenesis and suggest species-specific media composition for each step in somatic embryogenesis. The findings provide insights into their developmental processes and informing future research and applications in somatic embryogenesis and forestry breeding.

Exploring Taxonomic and Genetic Relationships in the Pinus mugo Complex Using Genome Skimming Data.

Genome skimming is a novel approach that enables obtaining large-scale genomic information based on high-copy DNA fractions from shallow whole-genome sequencing. The simplicity of this method, low analysis costs, and large amounts of generated data have made it widely used in plant research, including species identification, especially in the case of protected or endangered taxa. This task is particularly difficult in the case of closely related taxa. The Pinus mugo complex includes several dozen closely related taxa occurring in the most important mountain ranges in Europe. The taxonomic rank, origin, or distribution of many of these taxa have been debated for years. In this study, we used genome skimming and multilocus DNA barcoding approaches to obtain different sequence data sets and also to determine their genetic diversity and suitability for distinguishing closely related taxa in the Pinus mugo complex. We generated seven different data sets, which were then analyzed using three discrimination methods, i.e., tree based, distance based, and assembling species by automatic partitioning. Genetic diversity among populations and taxa was also investigated using haplotype network analysis and principal coordinate analysis. The proposed data set based on divergence hotspots is even twenty-times more variable than the other analyzed sets and improves the phylogenetic resolution of the Pinus mugo complex. In light of the obtained results, Pinus × rhaetica does not belong to the Pinus mugo complex and should not be identified with either Pinus uliginosa or Pinus rotundata. It seems to represent a fixed hybrid or introgressant between Pinus sylvestris and Pinus mugo. In turn, Pinus mugo and Pinus uncinata apparently played an important role in the origins of Pinus uliginosa and Pinus rotundata.

Transcriptome and Metabolome Based Mechanisms Revealing the Accumulation and Transformation of Sugars and Fats in Pinus armandii Seed Kernels during the Harvesting Period.

Pinus armandii seed kernel is a nutrient-rich and widely consumed nut whose yield and quality are affected by, among other things, harvesting time and climatic conditions, which reduce economic benefits. To investigate the optimal harvesting period of P. armandii seed kernels, this study determined the nutrient composition and seed kernel morphology and analyzed the gene expression and metabolic differences of P. armandii seed kernels during the harvesting period by transcriptomics and metabolomics. The results revealed that during the maturation of P. armandii seed kernels, there was a significant increase in the width, thickness, and weight of the seed kernels, as well as a significant accumulation of sucrose, soluble sugars, proteins, starch, flavonoids, and polyphenols and a significant decrease in lipid content. In addition, transcriptomic and metabolomic analyses of P. armandii seed kernels during the harvesting period screened and identified 103 differential metabolites (DEMs) and 8899 differential genes (DEGs). Analysis of these DEMs and DEGs revealed that P. armandii seed kernel harvesting exhibited gene-metabolite differences in sugar- and lipid-related pathways. Among them, starch and sucrose metabolism, glycolysis, and gluconeogenesis were associated with the synthesis and catabolism of sugars, whereas fatty acid degradation, glyoxylate and dicarboxylic acid metabolism, and glycerophospholipid metabolism were associated with the synthesis and catabolism of lipids. Therefore, the present study hypothesized that these differences in genes and metabolites exhibited during the harvesting period of P. armandii seed kernels might be related to the accumulation and transformation of sugars and lipids. This study may provide a theoretical basis for determining the optimal harvesting time of P. armandii seed kernels, changes in the molecular mechanisms of nutrient accumulation, and quality directed breeding.

Effects of Combined Nitrogen-Phosphorus on Biomass Accumulation, Allocation, and Allometric Growth Relationships in Pinus yunnanensis Seedlings after Top Pruning.

Pinus yunnanensis (Franch), a species endemic to southwestern China, provides significant ecological and economic benefits. The quality of afforestation can be enhanced by promoting high-quality sprout growth. This study analyzed the effects of six fertilization treatments following top pruning: T1 (N: 0 g/plant-1; P: 0 g/plant-1), T2 (N: 0 g/plant-1; P: 2 g/plant-1), T3 (N: 0 g/plant-1; P: 4 g/plant-1), T4 (N: 0.6 g/plant-1; P: 0 g/plant-1), T5 (N: 0.6 g/plant-1; P: 2 g/plant-1), and T6 (N: 0.6 g/plant-1; P: 4 g/plant-1). The accumulation and allocation of aboveground biomass in roots, stems, and leaves of P. yunnanensis were measured, as well as changes in biomass per plant at 90 days (early stage), 180 days (middle stage), and 270 days (late stage) post-fertilization. At 90 days, root biomass accumulation in T3 was significantly higher, by 13.31%, compared to that in T1 (p < 0.05). The growth rates of stem and plant biomass followed the order T6 > T1 > T3 > T5 > T4 > T2. The biomass of sprouts and individual plants exhibited allometric growth under T1, T5, and T6 treatments. At 180 days, needle biomass allocation in T1 and T4 increased by 7.47% and 8.6%, respectively, compared to 90 days. Combined nitrogen-phosphorus fertilization significantly influenced aboveground biomass allocation, promoting growth more effectively than other treatments. By 270 days, the stem and individual biomass in T2 and T3 treatments showed significant differences (p < 0.01) compared to other treatments. Overall, root, stem, and sprouts were primarily influenced by phosphorus fertilization, while nitrogen fertilization notably promoted needle and leaf growth in later stages. The aboveground components were more affected by phosphorus fertilization. The combination of nitrogen and phosphorus fertilizers enhanced early-stage stem and sprouts, as well as late-stage root development.

Combinative effects of thinning and prescribed burning on fuel reduction and soil arthropods: A case study in a Mediterranean pine forest.

Wildfire pressure involves today to implement silvicultural practices that provide a good compromise between reducing fire risk and maintaining ecological functioning. Thinning reduces tree density and low branches, but results in the deposition of a considerable biomass of woody debris on the ground (up to 4800 g m2 in this study). They can be eliminated by prescribed burning, but this raises questions about the fire intensity that can be generated and the impact on soil fauna. We undertook the monitoring of a thinning and prescribed burning operation, separated and combined, in November 2020, in a Pinus laricio stand prone to fire risk, located in Bavella, Corsica. Fuel load was determined, and temperature measurements in the soil were performed using K-type thermocouples. Soil arthropod populations were monitored using pitfall traps, in particular Collembola, Acari, Aranae, and Coleoptera. The combination of thinning and burning resulted in a fire intensity of 75.8 versus 8.4 kW m-1 for burning alone. Maximum temperature rise measured at -2 cm below the surface was less than 5°C for both treatments. The combination of thinning and burning did not result in higher fire intensity at ground level than burning alone, and the soil showed high insulation capacity. Most of the woody debris that burned was small-diameter, and large-diameter debris remained unconsumed. This burning, performed during a period of low biological activity, had no effect on soil arthropods, and the presence of large debris may have provided refuge areas. Collembola group was the faster to recover, and were followed by cohorts of predators in summer, especially Acari. Our results suggest that a combination of burning and thinning in autumn may be beneficial for fire prevention. However, the decomposition of woody debris in relation to fire risk, and the occurrence of pests after these treatments need to be monitored.

Wet and dry spell induced changes in the soil CO2 effluxes of Pine and Oak ecosystems of Central Himalaya: a comparative assessment for monsoon and winter seasons.

Soil efflux of CO2 ( F CO 2 ) is known to be dependent on natural drying and rewetting of the soil. Although the central Indian Himalayan region is predominantly occupied with two ecosystems, i. e. Pine (Pinus roxburghii) and Oak (Quercus leucotrichophora), differences in their F CO 2  dynamics and responses of F CO 2  to varying wet and dry spells were hardly known. To address this knowledge gap, this study provides a comparative assessment of F CO 2  variability from Pine and Oak ecosystems of central Himalaya as a response to rainfall induced wet and dry spells of monsoon and winter seasons. The F CO 2  data presented in this study are collected for 242 days of 2021-22 that include monsoon and winter seasons from a Pine and an Oak sites. The mean F CO 2 s of Pine and Oak sites are found to be 3.95(± 0.02) and 3.61(± 0.01) µmol.m-2.s-1, respectively. We find that the winter reduction in the F CO 2  in comparison to monsoon at the Pine site (78%) is more substantial than at Oak site (64.6%). The cross wavelet spectra of F CO 2  and monsoon rainfall amount at the Oak site, unlike the Pine site, indicate a negative relationship. The rainfall spell duration and amount of monsoon wet spells are noted to have an inverse relationship with F CO 2  at both sites, although, increasing rainfall spell duration in winter is noted to increase F CO 2  at Pine and Oak sites. Similarly, increasing F CO 2  is observed with increasing dry spells of monsoon at both sites. Results of this study indicate that in comparison to Oak, F CO 2  variability at Pine ecosystem is primarily driven by abiotic factors wherein wet spell is a major determinant.

Response of soil-microbe-extracellular enzyme stoichiometric characteristics to nitrogen deposition in a Pinus yunnanensis forest in central Yunnan Province, Southwest China.

To understand the effects of nitrogen deposition on element cycling and nutrient limitation status in forest ecosystems, we examined the effects of nitrogen deposition on the stoichiometric characteristics of forest soil-microbial-extracellular enzymes in Pinus yunnanensis forest. We conducted a field experiment with control (CK, 0 g N·m-2·a-1), low nitrogen (LN, 10 g N·m-2·a-1), medium nitrogen (MN, 20 g N·m-2·a-1) and high nitrogen (HN, 25 g N·m-2·a-1) since 2019. We collected soil samples (0-5 cm, 5-10 cm and 10-20 cm) at September 2022, and measured the contents of soil organic, total nitrogen, total phosphorus, microbial biomass carbon, nitrogen and phosphorus (MBC, MBN, MBP) and the activities of C, N, and P acquisition enzymes. The results showed that nitrogen deposition significantly reduced soil organic content, C:N and C:P by 6.9%-29.8%, 7.6%-45.2% and 6.5%-28.6%, and increased soil total N content and N:P by 10.0%-45.0% and 19.0%-46.0%, respectively. Nitrogen addition did not affect soil total P content. Except for soil C:N and C:P, soil nutrient content and stoichiometric ratio were highest in 0-5 cm soil layer. MN and HN treatments significantly decreased MBN by 11.0%-12.7%. MBC, MBP, and their stoichiometry did not change significantly under nitrogen deposition. Soil microbial nutrient content in 0-5 cm soil layer was significantly higher than that in other soil layers. Nitrogen deposition significantly decreased the activities of cellobiose hydrolase and leucine aminopeptidase (decreased by 14.5%-16.2% and 48.7%-66.3%). HN treatment promoted ß-1,4-glucosidase activity (increased by 68.0%), but inhibited soil enzyme stoichiometric carbon to nitrogen ratio and nitrogen to phosphorus ratio (decreased by 95.4% and 88.4%). LN and MN treatment promoted ß-1,4-N-acetylglucosaminidase activity (increased by 68.3%-116.6%), but inhibited enzyme stoichiometric carbon to phosphorus ratio (decreased by 14.9%-29.4%). Alkaline phosphatase activity had no significant change. Soil enzyme activities were significantly decreased with increasing soil depth. Soil total N and total P and microbial nutrients were negatively correlated with vector angle (representing microbial nitrogen or phosphorus limitation), while vector length (representing microbial carbon limitation) was consistently significantly positively correlated with vector angle, suggesting the synergistic promotion between microbial carbon limitation and phosphorus limitation. Nitrogen deposition gradually shifted to phosphorus limitation while alleviating microbial nitrogen limitation in P. yunnanensis forest. In addition, microbial activities in this region was limited by C availability, and the relationship between microbial C and P limitation was proportional.

Growth difference of planted Pinus koraiensis from different provenances in Maoer Mountain, China.

In order to analyze the growth pattern of tree height of planted Pinus koraiensis and screen the provenances with fastest growth, we grouped the provenances using the differences in tree height, diameter at breast height (DBH) and volume of timber of 234 individuals of planted P. koraiensis from 26 provenances in Maoershan Experimental Forest Farm. We constructed the growth equation for tree height by combining the base models of Gompertz, Korf, Richards, Logistic, and Schumacher, and then selected the optimal one. We introduced the prove-nance grouping as a dummy variable into the base model, and evaluated the optimal tree height growth equation by a comprehensive evaluation of the model according to the coefficient of determination (R2), the root-mean-square error (RMSE), the Akaikei Information Criterion (AIC), and the model's predictive precision (FP). The results showed that the growth traits of the 26 provenances had significant difference among the groups, and that tree height and DBH showed significant differences among the provenances. According to the comprehensive consideration of different growth traits, the four groups of provenance growth were divided into group A (Wuying, Hebei, Linjiang, Dongfanghong, Huanan, Lushuihe, Fangzheng) >group B (Aihuisanzhan, Liangshui, Tieli, Qinghe) > group C (Wuyiling, Zhanhe, Liangzihe, Baihe, Chaihe, Caohekou, Bajiazi) >group D (Tongzigou, Dashitou, Wangqing, Helong, Yanshou, Dahailin, Xiaobeihu, Muling). The optimal base tree height growth model of the four groups was the Gompertz model, and the fitting accuracy of the model after the introduction of dummy variables (R2=0.9353) was higher than that of the base model (R2=0.9303), and the model prediction accuracy was also improved. The tree height growth curves of each provenance group conformed to the "S"-shaped rule of change. There were obvious differences among the groups, with the best performance of the provenances in group A. The growth of P. koraiensis from different provenances was different, and the tree height growth model with dummy variables of provenance groups could effectively improve the prediction accuracy of the model, reflect the differences in height growth of P. koraiensis of different provenances, which could provide the scientific basis for the selection and cultivation of P. koraiensis plantations.

Rhizosphere effects and microbial N limitations drive the root N limitations in the rhizosphere during secondary succession in a Pinus tabuliformis forest in North China.

Introduction: Rhizosphere effects (REs) have recently been identified as important regulators of root and microbial nutrient acquisition and are positively involved in nutrient cycling of belowground carbon (C), nitrogen (N), and phosphorus (P). Nutrient conditions of the fine roots and soil N are likely to influence REs. Still, it is unclear how REs of soil nutrients themselves variably impact the supply of nutrients to plants in terms of the responses to soil N due to succession. Methods: In this study, we applied both fine roots and extracellular enzymes for vector analysis and stoichiometry of N:P to explore the metabolic limitations of roots and rhizospheric soil microbes and their relationships with REs across five levels of soil N (0, 5, 10, 15, and 20 kg N m-2 year-1) along successional age classes of 42, 55, and 65 years in a Pinus tabuliformis forest. Results: Overall, the metabolism of root and rhizospheric soil microbes was mediated by soil N. N limitation of roots initially decreased before increasing, whereas that of microbes demonstrated opposite trends to the N levels owing to competition for inorganic N between them by REs of NO3 --N. However, N limitations of both roots and microbes were alleviated in young stands and increased with succession after the application of N. In addition, root N limitations were manipulated by REs of three different soil N-related indicators, i.e., total N, NH4 +-N, and NO3 --N. Rhizospheric soil microbial N limitation was almost unaffected by REs due to their strong homeostasis but was an important driver in the regulation of root N limitation. Discussion: Our results indicated that successional age was the most critical driver that directly and indirectly affected root N metabolism. However, the level of N application had a slight effect on root N limitation. Microbial N limitation and variations in the REs of N indicators regulated root N limitation in the rhizosphere. As a result, roots utilized REs to sequester N to alleviate N limitations. These findings contribute to novel mechanistic perspectives on the sustainability of N nutrition by regulating N cycling in a system of plant-soil-microbes in the rhizosphere to adapt to global N deposition or the heterogeneous distribution of bioavailable soil N with succession.

Unveiling the Chemical Constituents and Inhibitory Roles of Extracts from Pinus pinea L. Nut and Nutshell: A Novel Source for Pharmaceutical Antimicrobials.

Antibiotic resistance in infectious diseases has been a serious problem for the last century, and scientists have focused on discovering new natural antimicrobial agents. Pinus pinea has been used as a natural pharmacotherapeutic agent with antimutagenic, anticarcinogenic, and high antioxidant properties. In this study, GC-MS and LC-HR/MS were employed to analyze Pinus pinea L. nut and nutshell extracts. DPPH radical scavenging assay was performed to analyze the antioxidant properties of the extracts, but no activity was determined. GC-MS analysis showed that linoleic, oleic, and palmitic acids were the three most dominant fatty acids in nut and nutshell extracts, with ratios between 6.75% and 47.06% (v/v). LC-HR/MS revealed that the nutshell methanol extract had a higher phenolic content than other extracts, with vanillic acid (1.4071 mg/g). Antimicrobial activity assays showed that the minimum inhibitory concentrations (MIC) of the extracts varied between 5.94 and 190 mg/mL, and the most significant inhibition was seen in the nutshell methanol extract (MICs: between 5.94 and 47.5 mg/mL). Consequently, the antimicrobial activity of the extracts can be attributed to the dense fatty acids they contain, and the nutshell methanol extract showed the most potent inhibition related to the abundance of phenolic compounds in the extract.

Watering the trees for the forest: Drought alleviation in oaks and pines by ancestral ditches.

Traditional ditches ("acequias" in Spanish) derive meltwater and infiltrate groundwater providing ecological services downstream in the semi-arid Sierra Nevada range (SE Spain). Therefore, they may act as a nature-based solution by alleviating drought stress in trees growing near ditches by enhancing growth and reducing their intrinsic water-use efficiency (iWUE). Such a mitigation role of acequias is critical given that some oak (Quercus pyrenaica) and pine (Pinus sylvestris) stands reach their xeric distribution limits in Europe. We compared tree-ring width data and wood δ13C, a proxy of iWUE, in oak and pine stands located near or far (control) from ditches with different infiltration capacity in two watersheds. We assessed how trees responded to climate data, drought stress, and vegetation greenness through correlations and resilience indices. Oak trees located near ditches grew more and responded less to precipitation, soil moisture, a drought index, and greenness than control trees. In pines, we did not find this pattern, and ditch trees grew more than control trees only during an extremely dry year (1995). Climate-growth correlations suggested a longer growing season in ditch pines. Growth of ditch oaks from the "Acequia Nueva" (AN), with high infiltration capacity, responded more to autumn soil moisture and showed the lowest δ13C. Growth was enhanced by cool-wet spring conditions in pines and also by warm-wet conditions in the prior winter in the case of oaks. Control trees showed lower resistance to drought. Control trees presented higher wood δ13C values except for old oaks from the "Acequia Grande" (AG) site which may show long-term acclimation. Traditional ditches alleviate drought stress in oak and pine stands subjected to regional xeric climate conditions.

Dependence of Pinus sylvestris (Pinaceae) Radial Growth on Meteorological Conditions and Anthropogenic Air Pollution: Data from Northwestern Part of Murmansk Oblast.

The influence of meteorological factors and anthropogenic air pollution on the radial growth of the Scots pine Pinus sylvestris L. was studied as dependent on the distance from the Pechenganickel mining and metallurgical plant (Nikel, Murmansk region). Three (control, buffer, and impact) zones of the pollution gradient were identified based on the contents of main polluting elements (S, Ni, and Cu) in the forest litter. A significant weakening of pine stands was observed in the impact zone and attributed to the combined effect of long-term anthropogenic pollution of the 1970s and unfavorable weather events of the mid-1980s. As the emission decreased from 1988 to 2018, the radial increment of P. sylvestris was observed to increase significantly (by up to 44%) in the impact zone and to remain much the same in the control and buffer zones. More recently, the radial increment of trees in the impact zone reached and even exceeded the values observed in the control zone, although the trees examined were relatively old. The finding demonstrated again the high adaptive capacity of P. sylvestris.

Hydrothermal environments lead to differences in the radial growth response of Pinus tabulaeformis to climate in the monsoon marginal zone, Northwestern China.

Regional climatic differences increase the complexity of tree radial growth responses to climate change in the monsoon marginal zones and may alter the carbon sequestration capacity of forests. In this study, we collected cores of Pinus tabulaeformis trees at nine sampling sites across different regions. We analysed the relationship between tree-ring width chronology and climatic factors at different sites using dendroecological methods. We used the tree-ring index to calculate resistance, recovery, and resilience as well as to explore the capacity of radial growth to cope with drought events. The results indicate that (1) Drought was the primary factor limiting tree growth, and tree-ring climate response patterns varied across three regions. Tree growth was sensitive to both temperature and precipitation in the eastern Qilian Mountains, while it was more sensitive to temperature in the Hassan Mountains and more sensitive to precipitation in the Helan Mountains. (2) The tree-ring climate response pattern remained unstable over time, and the relative influence of current climate on tree growth increased. (3) The ecological resilience of trees to extreme events varies across three regions, which could be attributed to regional moisture conditions and the duration of drought. In the context of the management and protection of trees in the study area in the future, more attention should be paid to the elasticity of tree growth after drought events.