Extreme environments foster phylogenetically diverse microorganisms and unique community assembly patterns. Plateau saline marsh lakes represent understudied extreme habitats characterized by dual stressors of high salinity and low temperature. Here, we analyzed the soil bacterial and archaeal diversity in three salt marshes of the Qaidam Basin on the Qinghai-Tibetan Plateau, China. While the bacterial and archaeal alpha diversity showed no significant differences among the three salt marshes, the community composition varied significantly. Notably, soil salinity (indicated by electric conductivity, EC) exerted opposing effects on microbial diversity—suppressing bacterial while promoting archaeal communities. Stochastic processes were the predominant mechanism for both bacterial and archaeal community assembly, where the weights were, in descending order, drift, homogeneous selection, and dispersal limitation. Network analysis revealed predominantly positive co-occurrence patterns within both bacterial and archaeal communities. We did not find a direct relationship between any bacterial or archaeal co-occurrence network properties and soil EC, but there was a significant correlation of network complexity to microbial diversity, which was influenced by EC. Our findings indicate distinct responses of bacterial and archaeal diversity to varying salinity levels, while the underlying assembly processes appear to be conserved in driving shifts in community diversity in plateau salt marsh wetlands.

Soil salinization is a growing global concern in many ecosystems. Although ectomycorrhizal fungi have been shown to alleviate the effects of salinity in some tree species, uncertainties persist concerning their effectiveness when plants are exposed to different salinity levels that are commonly present in salt-affected soils. Quercus dentata seedlings either non-inoculated (mycorrhizal control) or inoculated with the ectomycorrhizal fungus Laccaria bicolor were then treated with three NaCl concentrations (0, 0.4%, and 0.8%). The physiological, stoichiometric, and growth characteristics of the plants were examined. NaCl significantly affected seedling growth and physiology. However, the impact of L. bicolor on Q. dentata seedlings could shift in response to varying salt concentrations. Under moderate salinity, inoculation of L. bicolor increased root biomass by 4.55% and leaf chlorophyll concentrations by 46.8%, and decreased leaf Na⁺ concentrations and the Na⁺/K⁺ ratios. Under high salinity, L. bicolor decreased leaf water content and fluorescence parameters, and increased leaf Na⁺ concentrations. The effect of ectomycorrhizal fungus L. bicolor on Q. dentata seedlings was dependent on NaCl concentration, and our results indicate that the use of L. bicolor in afforestation efforts with Q. dentata would only be effective under relatively low soil salinity levels.

Background Soil salinization is a growing global concern in many ecosystems. Although ectomycorrhizal fungi have been shown to alleviate the effects of salinity in some tree species, uncertainties persist concerning their effectiveness when plants are exposed to different salinity levels that are commonly present in salt-affected soils. Objective This study explored the effects of Laccaria bicolor on Quercus dentata seedlings under different levels of salt stress. Methods Q. dentata seedlings were grown in pots and were either non-inoculated (mycorrhizal control) or inoculated with the ectomycorrhizal fungus L. bicolor. The seedlings were then treated with three NaCl concentrations (0, 0.4%, and 0.8%), that was added to the soil for 30 days, after which plant physiological, stoichiometric, and growth characteristics were examined. Results NaCl exposure significantly impaired growth and physiological parameters in all seedling groups. The influence of L. bicolor on Q. dentata seedlings varied with salt concentration. Under moderate salinity, the seedlings colonized by L. bicolor exhibited an enhancement in root biomass and leaf chlorophyll concentrations, concomitant with a reduction in leaf Na⁺ concentrations and the Na⁺/K⁺ ratios. Conversely, under relatively high salinity, colonization of L. bicolor was associated with a reduction in leaf water content and fluorescence parameters, as well as an elevation in leaf Na⁺ concentrations. Conclusions The effect of ectomycorrhizal fungus L. bicolor on Q. dentata seedlings was dependent on NaCl concentration, and our results indicate that the use of L. bicolor in afforestation efforts with Q. dentata would only be effective under relatively low soil salinity levels.

Urban wetlands, encompassing both natural and constructed ecosystems, are vital for urban resilience. Understanding how plant functional traits adapt to these distinct habitats is crucial for ecological management. This study investigates the intraspecific variation and trait covariation patterns of the common reed (Phragmites australis) in two contrasting urban wetland types in Ganzhou City: a stagnant, engineered constructed wetland and a dynamic, natural riverine wetland. This contrast represents a key gradient in hydrological regime and anthropogenic influence. We measured 22 morphological and chemical traits to assess trait differences, variability (coefficient of variation), and correlation patterns. Volcano plot analysis revealed significant habitat effects: reed in natural wetlands exhibited higher levels of Cu, P, N, and leaf moisture content (LMC), whereas those in constructed wetlands had higher Ca content. Traits such as Na, Mn, and Al showed high intraspecific variability. Correlation analyses revealed significant trade-offs and integrations among traits, such as positive correlations between LMC and nutrients (K, Cu), and negative correlations between Ca and key leaf morphological traits. Principal component analysis (PCA) further confirmed a significant separation along PC1, driven primarily by nutrient elements (Cu, P, K) and LMC, with natural wetlands scoring higher. In contrast, PC2, associated with leaf morphological traits (e.g., leaf area, leaf width), showed no significant inter-habitat difference. Our findings demonstrate that P. australis employs distinct ecological strategies by adjusting its functional traits and resource allocation in response to different urban wetland environments. This highlights the critical role of intraspecific trait variation in plant adaptation and has important implications for wetland restoration and the design of constructed ecosystems.