Search Results (44)

Phosphorus (P) availability is a major constraint on plant growth in many forest ecosystems, yet the strategies by which different tree species acquire and utilize various forms of soil phosphorus remain poorly understood. This study investigated how coexisting tree species with contrasting mycorrhizal types, specifically arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) associations, respond to different phosphorus forms under field conditions. An in situ root bag experiment was conducted using four phosphorus treatments (control, inorganic, organic, and mixed phosphorus) across four subtropical tree species. A comprehensive set of fine root traits, including morphological, physiological, and mycorrhizal characteristics, was measured to evaluate species-specific phosphorus foraging strategies. The results showed that AM species were more responsive to phosphorus form variation than ECM species, particularly under inorganic and mixed phosphorus treatments. Significant changes in root diameter (RD), root tissue density (RTD), and acid phosphatase activity (RAP) were observed in AM species, often accompanied by higher phosphorus accumulation in fine roots. For example, RD in AM species significantly decreased under the Na₃PO₄ treatment (0.94 mm) compared to the control (1.18 mm), while ECM species showed no significant changes in RD across treatments (1.12–1.18 mm, p > 0.05). RTD in AM species significantly increased under Na₃PO₄ (0.030 g/cm³) and Mixture (0.021 g/cm³) compared to the control (0.012 g/cm³, p < 0.05), whereas ECM species exhibited consistently low RTD values across treatments (0.017–0.020 g/cm³, p > 0.05). RAP in AM species increased significantly under Na₃PO₄ (1812 nmol/g/h) and Mixture (1596 nmol/g/h) relative to the control (1348 nmol/g/h), while ECM species showed limited variation (1286–1550 nmol/g/h, p > 0.05). In contrast, ECM species displayed limited trait variation across treatments, reflecting a more conservative acquisition strategy. In addition, trait correlation analysis revealed stronger coordination among root traits in AM species. And AM species exhibited high variability across treatments, while ECM species maintained consistent trait distributions with limited plasticity. These findings suggest that AM and ECM species adopt fundamentally different phosphorus acquisition strategies. AM species rely on integrated morphological and physiological responses to variable phosphorus conditions, while ECM species maintain stable trait configurations, potentially supported by fungal symbiosis. Such divergence may contribute to functional complementarity and species coexistence in phosphorus-limited subtropical forests. Full article

Soil aggregate stability plays a pivotal role in ecosystem functioning and carbon sequestration. Nitrogen deposition influences aggregate stability and drives differential responses in AM and ECM fungi, yet the underlying mechanisms remain unclear. This study aimed to determine how N addition influences soil aggregation, mycorrhizal morphological characteristics, and soil organic carbon (SOC) across two mycorrhizal types. A temperate forest experiment was conducted in northeastern China using 12 plots subjected to four N treatments (control, low, medium, high). Soil properties, soil aggregate traits, mycorrhizal morphological characteristics, and aggregate distributions were quantified. Relationships were examined via correlation analyses, random forest models, and structural equation modeling. N enrichment substantially increased SOC and soil water content, enhancing the proportion of large soil aggregates (4–8 mm) and elevating mean weight diameter (MWD) and geometric mean diameter (GMD), two critical indicators of soil aggregate stability. AM fungi exhibited a stronger response to N addition than ECM, reflected in greater hyphal development and carbon accumulation. SOC and water content correlated positively with aggregate stability, whereas soil pH showed a negative association. N inputs enhance soil structural stability by promoting SOC and water retention, with AM fungi demonstrating heightened sensitivity to N addition. These findings emphasize the integral role of mycorrhizal dynamics in shaping soil carbon stabilization under increasing N deposition. Full article

The interaction between woody plants and mycorrhizal fungi is an important biological interaction; however, the driving factors behind the diversity of mycorrhizal trees formed through the symbiosis of mycorrhizal fungi and woody plants remain unclear. In this study, we collected and compiled the woody plant data of 34 forest dynamic plots containing 3350 species from habitats around the world and divided them into AM and EcM trees. We tested the contribution of AM and EcM trees to tree diversity and its components in forest communities worldwide. Our results showed that AM trees rather than EcM trees affect the tree diversity of forest communities, and that the diversity of AM trees has a significant latitudinal gradient pattern. Climate variables, especially temperature, are strongly correlated with the diversity patterns for AM trees rather than EcM trees. Topography is the most significant factor affecting the diversity of EcM trees. Our findings highlight the importance of AM trees for the tree diversity of forest communities worldwide. Our findings have important implications for understanding the response of complex woody plant communities with different types of mycorrhizal symbiosis to climate change. Full article

The growth of forest trees in the relatively young soils of Europe has historically been limited by nitrogen (N). The high anthropogenic N deposition and intense forest management during the last century, however, have caused forest trees in large areas to show signs of being limited by phosphorus (P) or base cations. This indicates that the current situation is not sustainable. The net addition of N to forests here stems from deposition and N fixation, both processes that add N to the topsoil. Phosphorus and cations are released by weathering in the mineral soil. Do European trees have what it takes to efficiently take up P and cation nutrients when they become scarce? Important factors influencing their capacity to take up P and cations are their roots’ distribution and function, mycorrhizal distribution and type, and the response of their root and mycorrhizal growth and function to N depositions and nutrient deficiencies. The literature shows that the ability to be limited by something other than nitrogen will be hardest for shallow-rooted conifer trees, followed by ectomycorrhizal deciduous trees; arbuscular mycorrhizal trees will handle the shift best. This knowledge should be incorporated into forest growth models to promote sustainable management decisions. Full article

This study investigates the effects of forest aging on ectomycorrhizal (EcM) fungal community and foraging behavior and their interactions with plant–soil attributes. We explored EcM fungal communities and hyphal exploration types via rDNA sequencing and investigated their associations with plant–soil traits by comparing younger (~120 years) and older (~250 years) temperate forest stands in Northeast China. The results revealed increases in the EcM fungal richness and abundance with forest aging, paralleled by plant–soil feedback shifting from explorative to conservative nutrient use strategies. In the younger stands, Tomentella species were prevalent and showed positive correlations with nutrient availability in both the soil and leaves, alongside rapid increases in woody productivity. However, the older stands were marked by the dominance of the genera Inocybe, Hymenogaster, and Otidea which were significantly and positively correlated with soil nutrient contents and plant structural attributes such as the community-weighted mean height and standing biomass. Notably, the ratios of longer-to-shorter distance EcM fungal exploration types tended to decrease along with forest aging. Our findings underscore the integral role of EcM fungi in the aging processes of temperate forests, highlighting the EcM symbiont-mediated mechanisms adapting to nutrient scarcity and promoting sustainability in plant–soil consortia. Full article

The coordination between leaf and root traits is conducive to an integrated understanding of whole-plant ecological strategies and reveals how community composition and diversity contribute to defining the functions and services of ecosystems. However, there is limited understanding regarding the impact of species richness and trait categories on the coordination between leaf and root traits. Based on a 9-year common garden experiment, we investigated the leaf and fine root traits of 56 plots (25.8 m × 25.8 m) encompassing various trait categories (trait categories were defined according to the root depth, leaf habit, and mycorrhizal type) and different levels of species richness (1, 2, 4, 8) in the context of a forest biodiversity and ecosystem functioning experiment conducted in subtropical China (BEF-China). We found the following: (1) Our findings indicate that there was generally a significant difference in leaf traits, occasionally in absorptive root traits, and no difference in transport root traits between different trait categories. (2) Conversely, species richness significantly influenced all transport root traits except root nitrogen and most leaf and absorptive root traits. (3) The results demonstrated that trait categories played a crucial role in the coordination between leaf and fine root traits. Additionally, the coordination between leaf and fine root traits increased with higher species richness, particularly in deep-rooted, evergreen, and ectomycorrhizal fungi species. Furthermore, the coordination between leaf and fine root traits was significantly lower in monocultures compared to four- and eight-species mixtures. These results suggest that a significant mixture effect exists in the coordination between leaf and fine root traits due to the comprehensive and divergent capture of above- and belowground resources and reduced intraspecific competition. Therefore, compared to monocultures, mixed-species stands can enhance the coordination of leaf and fine root traits, and it is advisable to establish forests with mixtures of more than four species, dominated by deep-rooted, evergreen, and ectomycorrhizal fungi species, to maintain ecosystem stability and functional integrity. Full article

The crucial functional arbuscular mycorrhizal fungi (AMF) and diazotrophs play pivotal roles in nutrient cycling during vegetation restoration. However, the impact of managed vegetation restoration strategies on AMF and diazotroph communities remains unclear. In this study, we investigated the community structure and diversity of AMF and diazotrophs in a karst region undergoing managed vegetation restoration from cropland. Soil samples were collected from soils under three vegetation restoration strategies, plantation forest (PF), forage grass (FG), and a mixture of plantation forest and forage grass (FF), along with a control for cropland rotation (CR). The diversity of both AMF and diazotrophs was impacted by managed vegetation restoration. Specifically, the AMF Shannon index was higher in CR and PF compared to FF. Conversely, diazotroph richness was lower in CR, PF, and FG than in FF. Furthermore, both AMF and diazotroph community compositions differed between CR and FF. The relative abundance of AMF taxa, such as Glomus, was lower in FF compared to the other three land-use types, while Racocetra showed the opposite trend. Among diazotroph taxa, the relative abundance of Anabaena, Nostoc, and Rhizobium was higher in FF than in CR. Soil properties such as total potassium, available potassium, pH, and total nitrogen were identified as the main factors influencing AMF and diazotroph diversity. These findings suggest that AMF and diazotroph communities were more sensitive to FF rather than PF and FG after managed vegetation restoration from cropland, despite similar levels of soil nutrients among PF, FG, and FF. Consequently, the integration of diverse economic tree species and forage grasses in mixed plantations notably altered the diversity and species composition of AMF and diazotrophs, primarily through the promotion of biocrust formation and root establishment. Full article

Camellia oleifera, a key economic forestry species in southern China, struggles with low productivity due to suboptimal planting management. Recently, transforming old or unadopted varieties of C. oleifera plantations has been recognized as a means to enhance economic benefits and production. However, the impact of these transformations on soil properties and fungal communities has received little attention. In this study, we targeted pre-renewal old C. oleifera and post-renewal young C. oleifera, Pinus massoniana, and Cunninghamia lanceolata. Through field sampling and soil physicochemical property analysis, we developed a soil quality evaluation system that effectively analyzes fungal community structures and identifies key arbuscular mycorrhizal fungi (AMF) species for soil health. We found that the soil quality evaluation system for this region comprises pH, TK, AK, NO₃⁻, PO₄⁻ BG, ACP, F.simpson, AMF.shannon, and AMF.ace, which collectively indicated significant improvements in soil quality following transformation. Notably, the nutritional characteristics of the dominant fungal communities underwent marked changes, with an increase in pathogenic fungi in young C. oleifera and an expansion of ectomycorrhizal fungi in P. massoniana forests. The AMF communities in all four types of forest exhibited aggregation, and Scutellospora and Diversispora emerged as key species in the AMF community of C. oleifera. Additionally, Mortierella and Trichoderma were found to enhance plant resistance to pathogenic fungi. This study demonstrates that forestland transformation positively impacts soil quality and fungal community structure in C. oleifera, which provides valuable insights for future soil management in the region, both in terms of soil quality evaluation and fungal conservation. Full article

Bryophytes were traditionally ignored in most studies of forest ecosystem processes, or they were included with litter or soil. In the last few decades we have begun to understand their many roles that permit them to be ecosystem engineers. This review serves to pull together many scattered sources into a single source on the many contributions bryophytes can perform as ecosystem engineers and to support what several authors have already stressed: that bryophytes should not be treated as a single functional group. It puts bryophytes in perspective in terms of richness and biomass, then explores their roles as ecosystem engineers; that is, their roles in altering diversity, nutrient cycling, carbon sequestering, water retention, erosion depression, temperature modification, fire protection, fire and logging recovery, interactions with mycorrhizal fungi, effects on seed germination, and seedling survival. Interactions with other species are mentioned, but those regarding animals are largely omitted in favor of more detailed description of their relationships with trees throughout the world. Bryophytes provide both positive and negative interactions with forest trees, depending on the tree species, the ecosystem, and the bryophyte species. It is clear that different bryophytes have many different functional roles in sustaining the forest and making it suitable for germination, seedling success, and maintaining the mature forest. This review indicates those important roles and how they apply differently according to both tree and bryophyte species, and that different management practices are needed, depending on both bryophyte species and tree species, to sustain different forest types. Full article

Tree species composition in forest ecosystems is an important biological factor affecting the diversity of ectomycorrhizal fungi (EMF). However, little is known about the composition and diversity of EMF communities associated with Pinus massoniana in different P. massoniana association habitats (MpAHs) in subtropical mountains. This study investigated the EMF community characteristics of P. massoniana in different MpAHs using plant community surveys, soil property analyses, and mycorrhizal identification. A total of 56 operational taxonomic units (OTUs), belonging to 20 families and 22 genera, were identified. OTU richness of Basidiomycota (58.93%) was higher than that of Ascomycota (41.07%). Unclassified Helotiales, Russula, Lactarius, and Tomentella were the dominant groups. Different stand types significantly altered the EMF communities of P. massoniana (p < 0.05, for Shannon index) and the associations of P. massoniana + Populus adenopoda (Mp_Pa) had the highest diversity of EMF, while P. massoniana + Cunninghamia lanceolata (Mp_Cl) had the lowest diversity. The number of specific OTUs was higher than shared OTUs. Similarity index and principal coordinate analysis indicated that the EMF communities of P. massoniana varied significantly in different MpAHs (R² = 0.21, p = 0.001). The linear regression model showed that the EMF diversity of P. massoniana was positively related to tree species diversity, indicating that the EMF diversity of P. massoniana is influenced by tree species diversity. The findings provide a reasonable reference for tree species configuration in the process of mixed transformation or near-natural management of plantations. Full article

Fine roots are the most dynamic and physiologically active components of belowground tree organs. However, much remains unknown regarding the changes in fine root morphological characteristics during mycorrhizal colonization, especially in natural sites. The aim of this study was to analyze seasonal heterogeneity in fine roots and the mycorrhizal colonization of mature white poplar (Populus alba L.) trees under different soil conditions. Two floodplain forests were selected in Central Europe (Poland), which differed in soil moisture and structure. Fine roots were sampled during one growing season from the upper soil layer. Poplars were characterized by dual mycorrhizal colonization on one root system. It was, therefore, possible to investigate the contribution of two mycorrhizal types (arbuscular mycorrhiza—AM; and ectomycorrhiza—ECM) in response to different habitat conditions. The season was shown to be significant for all fine root features, as well as the degree of mycorrhizal colonization. Roots were better adapted to a drier habitat with a greater proportion of sand, mainly due to a reduction in the fine root diameter (FRD), while other root characteristics did not differ significantly. The degree of mycorrhizal colonization (RLC) and the proportion of arbuscular mycorrhizal structures (AM) were significantly and negatively correlated with the soil water content. A mutual competition between arbuscular mycorrhizas and ectomycorrhizas for poplar roots was also observed, particularly with respect to the season, site, and soil moisture. Changing environmental conditions (especially soil moisture) contribute not only to the morphological and functional changes of fine roots but also to changes in the proportion of arbuscular mycorrhiza and ectomycorrhiza. Understanding the mechanisms of adaptation of tree roots to changing environmental conditions is especially important in the context of climate change. Full article

In soils, high aggregate stability often represents higher quality and anti-erosion ability; however, few studies have systematically analyzed how different forest stands affect soil aggregate stability. We selected five typical mixed forest stands on Jinyun Mountain in Chongqing, China, as research sites to evaluate soil aggregate stability. Within these sites, we analyzed the factors influencing soil aggregate stability in different stands by measuring soil characteristics and root traits. Soil aggregation stability, plant root traits, and soil properties varied among the mixed forest stands. The broadleaf tree mixed forest improved soil aggregate stability by 57%–103% over that of the Pinus massoniana mixed forest. The soil organic carbon, cation exchange capacity, Fe-Al oxides, and fine root proportion were positively correlated with soil aggregate stability. The specific root length and very fine root proportion were negatively correlated with soil aggregate stability, whereas the fine root proportion was positively correlated with this property. Specifically, we found that arbuscular mycorrhizal fungi did not affect soil aggregate stability in acid rain areas. Structural equation modeling indicated that soil aggregate stability was closely related to soil physicochemical properties and plant root characteristics. Predictive factors accounted for 69% of the variation in mean weight diameter, and plant root traits influenced soil aggregate stability by affecting soil organic matter, texture, and Fe-Al oxides. This study elucidated the impact of soil physicochemical properties and plant root characteristics on soil aggregate stability in different forest stand types, which has crucial implications for optimizing the management of various forest types. Full article

Although they are a valuable edible ectomycorrhizal fungus, truffles (Tuber spp.) nevertheless face significant difficulties in the development of their scale. As a type of high economic value nut-like economic forest tree, the pecan (Carya illinoinensis) serves as a natural host for truffles. However, the technology for mycorrhizal synthesis in pecan has not yet been developed, and it is still unclear how certain microbes affect this process. In this study, we inoculated the pecan root system with a suspension of truffle spores and investigated the growth physiology of pecan seedlings with various infestation levels, as well as changes in the soil’s physicochemical properties and the makeup of the microbial community at the root level. The findings showed that tuber inoculation significantly increased the peroxidase activity of the pecan root system, significantly decreased the pH, and effective phosphorus content of mycorrhizosphere soil, while increasing the nitrate nitrogen content, and significantly increased the abundance and diversity of the mycorrhizosphere soil fungal community. Different groups of fungal and bacterial markers were formed in the mycorrhizosphere of pecan seedlings at different levels of infestation. In the highly infested group, Rozellomycota and lasiosphaeriaceae were the difference marker fungi, and Xanthobacteraceae, Rhizobiaceae as well as Streptococcaceae were the difference marker bacteria. In the low-infestation group, sphaerosporella was differential marker fungi, and Bacillus and Tumebacillus were differential marker bacteria. The fungal marker flora of the control group consisted of Chaetomium and Gilmaniella. Pseudomonas was the marker bacterial community. Additionally, these fungi included Collarina and Rozellomycota, and several bacteria from the genera Pseudomonas, Gemmatimonas, and others showed highly significant relationships with changes in soil pH, effective phosphorus, and nitrate nitrogen. In conclusion, pecan–truffle mycorrhizal seedlings have the potential to create the ideal microbial community structure needed for mycorrhizal growth, and these microorganisms have the potential to significantly alter the pH, effective phosphorus content, and nitrate nitrogen concentration of the mycorrhizosphere soil. Our results contribute to the understanding of how the mycorrhizosphere microbial community evolves when exogenous mycorrhizal fungi infest host plants and can offer some theoretical guidelines for growing pecan–truffle mycorrhizal seedlings. Full article

Aims: Microbial residue deposition is considered an important part of soil carbon sequestration. However, there is still a lack of understanding of the link between tree species composition and diversity and microbial carbon deposition, which hampers the rational selection and allocation of tree species for artificial carbon sequestration afforestation in northern China. Methods: In this study, plots from temperate planting forests (>60 years) were examined for the importance values of tree species, mycorrhizal types, tree diversity, and soil properties. Soil amino sugar was used as the biomarker to indicate the accumulation of fungi- and bacteria-derived carbon. Results: We found that tree species diversity and the importance values of tree species and mycorrhizal types were significantly positively correlated with soil microbial residual carbon. Hierarchical partitioning modeling showed that three groups of variables significantly affected soil microbial residual carbon, accounting for a total of 26.75% of the variation. Among them, tree species diversity accounted for the largest proportion (11.5%), and tree species diversity and importance values had a high joint impact (9.74%). The importance values of all AM-associated species constituted one of the most significant individual factors and could independently account for 10.9% of the variation in microbial residues. The findings of piecewise structural equation modeling showed that the importance of tree species had a large direct impact on GluN, GalN, and the GluN/MurN ratio. By influencing soil properties, the importance values of tree species also had indirect effects on soil microbial residual carbon. Conclusions: We suggest that an increase in the importance values of AM-associated tree species, such as Acer negundo L., will be accompanied by an increase in the total importance value of AM-associated tree species, which can significantly increase soil microbial residual carbon. Full article

Conspecific negative density dependence (CNDD) and habitat filtering are critical to seedling survival. However, the relative importance of the two processes in affecting survival of seedlings with different types of mycorrhizae remains unclear. In this study, the effects of CNDD and habitat filtering on the survival of tree seedlings with different mycorrhizal types were investigated at different successional stages of a temperate forest in the Changbai Mountain Natural Reserve, Northeast China. Conspecific negative density dependence and habitat filtering significantly affected seedling survival. In the early successional stage, the interactions between conspecific neighbor tree density and light availability and soil properties significantly negatively affected survival of all species and arbuscular mycorrhizal (AM) seedlings in the community, but not that of ectomycorrhizal (EcM) seedlings, and the CNDD effect was stronger on AM seedlings than on EcM seedlings. In the mid-successional stage, CNDD effects were stronger on EcM seedlings. Therefore, different types of mycorrhizal seedlings responded differently to CNDD and habitat filtering mechanisms during community succession, and thus, tree mycorrhizal association could determine the effects of CNDD and habitat filtering on seedling survival in temperate forests. Full article