Wangjun Li

We examined the morphological characteristics of a fungal isolate belonging to the genus Hypoxylon, isolated from rhizosphere soil of Patrinia scabiosaefolia in a phosphogypsum disposal site in Kaiyang County, Guizhou Province, China. We also analyzed its DNA sequences (ITS, LSU, tub2, and rpb2) and reconstructed a multi-gene phylogeny to determine its taxonomic placement and investigate its phylogenetic relationships with known Hypoxylon species. This isolate is characterized by production of conidiomata on water agar (WA) and one-celled hyaline, and ellipsoidal conidia. DNA-based phylogenies, inferred from a multi-locus dataset, show that our new species, H. kaiyangense sp. nov. (GT4-032) is closely related to H. ticinense in a fully supported subclade within Hypoxylon (Clade 6). However, significant nucleotide differences were observed across all gene loci between H. kaiyangense, H. ticinense and related species in Clade 6. The conidia of H. ticinense are significantly smaller than those of our new species while conidia of H. haematostroma are significantly larger. The new species possesses a rough-walled virgariella-like conidiogenous structure with roughened conidiogenous cells, whereas H. ticinense has a smooth, pale olivaceous conidiogenous structure with smooth conidiogenous cells bearing denticulate conidial secession scars. The morphological and phylogenetic evidence supports recognition of our isolate from this phosphogypsum environment as a novel species, for which the name Hypoxylon kaiyangense is proposed. This study not only enriches the diversity of Hypoxylon species in China but also provides research avenues for potential exploitation of such fungi in ecological restoration and bioremediation.

The coordinated variation between plant size and functional traits is a critical link connecting individual ecological strategies and community assembly. However, unlike angiosperms, the drivers of trait–size coordination in coexisting fern species remain unclear. This study sampled seven coexisting fern species in a subtropical secondary forest, measuring biomass (an indicator of plant size) and functional traits related to leaf and root morphology and elemental composition. The coordinated relationship between plant individual size and functional traits was investigated using regression and principal component analysis, while the relative contributions of phylogeny, species identity, and individual biomass to trait variation were quantified via Bayesian phylogenetic generalized linear mixed models. Results indicated that there is a clear trait–size coordination relationship. Specifically, significant linear or nonlinear relationships were identified between plant size and multiple functional traits (e.g., elemental concentrations, specific leaf area, and specific root length), indicating a transition from “fast-acquisitive” to “conservative” strategies. However, variance partitioning indicated that phylogeny and species identity together explained the majority of variation in leaf and root traits (71.4% on average), whereas the independent contribution of individual biomass was minimal (7.1% on average). The results suggest that although significant trait–size coordination exists in understory fern communities, this coordination is statistically dominated by evolutionary history (phylogeny and species identity), though the ecological significance of plant size remains evident in significant trait–size coordination patterns. Overall, the coordinated variation between plant size and functional traits is pivotal in forging resource-allocation strategies and fostering fern species coexistence, highlighting that evolutionary background must be foregrounded when disentangling the mechanisms of functional community assembly.

Phragmites australis is a well‐known invasive grass in North America, but its rapid expansion into new habitats within its native range is less documented. Here, we report a rapid expansion event of P. australis over the past decade in Caohai Lake, a plateau lake in China. Remote sensing and field surveys revealed that the reed population now covers 454.09 ha, constituting 3.8% of the protected area (approximately half of the total lake shoreline), with the most significant expansion occurring between 2018 and 2020. Ecological niche modeling with the previous records in China indicated a low habitat suitability (index = 0.354) for P. australis in this region. Despite this, our genetic analysis identified that all sampled individuals belong to haplotype P, an introduced octoploid lineage from eastern China. This finding excludes a natural range expansion from native populations in northern or southwestern China. The expansion is likely driven by anthropogenic habitat modification (e.g., “returning farmland to wetland”) and the introduction of this competitive genotype via constructed wetlands. Our study underscores the risk of “cryptic invasions” by introduced lineages within a species' native range and highlights the need for monitoring intraregional genotype translocations.

Phosphorus (P) availability critically limits plant growth in ecosystems. Plants adapt by regulating internal P fractions, yet how these fractions underpin ecological strategies in wild plants remains unclear. We investigated the allocation of P fractions in Yushania shuichengensis along a natural soil total P (TP) gradient (Low-P: 0.66, Moderate-P: 1.60, High-P: 2.73 g kg⁻¹) in the Yunnan-Guizhou Plateau. In leaves, concentrations of metabolic P (P_M) and lipid P (P_L) showed a unimodal response, peaking at the Moderate-P site (e.g., P_M increased by approximately 45% compared to the Low-P site), whereas the High-P site favored the storage of inorganic P (P_i) and residual P (P_R). In roots, P_i concentration increased linearly with soil TP, indicating a tight coupling with geochemical supply. Phosphorus resorption efficiency (PRE) decreased with increasing green leaf TP and P_M concentration but was unrelated to the relative allocation of P fractions. Net photosynthetic rate was governed by the absolute concentrations of P fractions rather than their reallocation. Conversely, root morphological traits were positively correlated with nucleic acid P allocation (rP_N), underscoring its role in promoting root elongation. Our findings reveal that Y. shuichengensis relies on regulating the concentrations of key P fractions in a context-dependent manner, rather than reallocating internal P, to adapt to soil P heterogeneity, with significant implications for its distribution and nutrient management.

Background: Plant leaves, branches, and roots synergistically govern survival, growth, and reproduction. However, while interspecific and community-level studies have advanced our understanding of organ coordination, intraspecific trait covariation remains poorly understood due to limited evidence. Methodology: This study investigated 28 functional traits across leaves, branches, and roots of Quercus rehderiana , a dominant species in rocky and non-rocky desertification forests, to evaluate intraspecific organ relationships. The traits, covering morphological, anatomical, and physiological aspects, reflect resource acquisition and utilization strategies. Standardized protocols were followed, with three replicates per individual for reliability. Results: Our results revealed no significant correlations among leaf, branch, and root traits in either forest type. Principal component analysis (PCA) of leaf traits indicated that the first axis was positively associated with water storage and utilization strategies, showing positive correlations with leaf thickness (LT), palisade mesophyll thickness (PT), and spongy mesophyll thickness (ST). The second axis exhibited a positive relationship with leaf nitrogen concentration (LNC) and leaf phosphorus concentration (LPC). For branch traits, the first axis reflected water transport efficiency, demonstrating positive associations with theoretical hydraulic conductivity ( K _t ) and vessel density (VD). The second axis was positively correlated with branch N concentration (BNC) and branch phosphorus concentration (BPC). In root traits, the first axis aligned with root defense traits (positive correlation) but was inversely related to resource acquisition efficiency. The second axis showed a positive correlation with root N concentration (RNC) and root phosphorus concentration (RPC). Conclusions: Organ-specific trait decoupling in Quercus rehderiana reveals independent above- and belowground adaptations to water and nutrient limitations, challenging whole-plant economic spectrum assumptions. While consistent in rocky desertification forests, they differ from other ecosystems, highlighting context-dependence. Future research should expand across environmental gradients to disentangle trait relationships. This work highlights multidimensional approaches in functional ecology for understanding plant adaptation.

Fine roots (diameter < 2 mm) play a crucial role in plants' acquisition of soil water and nutrients. Their morphological and chemical traits, which reflect resource utilization strategies, have garnered significant global research attention. However, the extent to which these traits are influenced by environmental conditions remains unclear. In this study, we measured 14 morphological and chemical traits from nine Quercus rehderiana individuals in both rocky and nonrocky desertification forest habitats. Our objectives were to identify the key factors shaping fine root traits and elucidate their adaptive strategies in the arid, nutrient‐poor conditions of rocky desertification forest ecosystems. The results revealed that Quercus rehderiana fine roots in rocky desertification forests exhibited higher root length (RL), root volume (RV), nitrogen (N), calcium (Ca), and magnesium (Mg) concentrations, along with an elevated nitrogen‐to‐phosphorus ratio (N:P ratio), compared to those in nonrocky desertification forests. Conversely, fine roots in nonrocky desertification forests showed greater phosphorus (P) and potassium (K) concentrations. Correlation analysis indicated that in rocky desertification forests, specific root length (SRL) and specific root area (SRA) were positively correlated with root P concentration, while root N concentration exhibited synergistic relationships with P and K. In contrast, nonrocky desertification forests displayed trade‐offs: SRL and SRA were negatively correlated with RV, root diameter (RD), and root tissue density (RTD), and root carbon (C) concentration was inversely related to Ca and Mg. Principal component analysis further demonstrated that rocky desertification forests favored a resource‐acquisition strategy, characterized by enhanced morphological traits and nutrient concentrations, whereas nonrocky desertification forests leaned toward a resource‐conserving strategy, prioritizing P and K accumulation. These findings highlight that Quercus rehderiana adapts to divergent environments through distinct resource allocation mechanisms, with its unique traits in rocky desertification forests underscoring its suitability for ecological restoration efforts.

Studying the response of plant leaf functional traits to elevation helps us understand plant adaptation to the environment and their distribution trends under global climate change. Currently, how plant leaf functional traits respond to elevation across different scales or among different species remains controversial. Quercus rehderiana Hand.-Mazz. is widely distributed across various altitude ranges in southwestern China, making it an ideal species to address this question. Therefore, this study established three 20 × 20 m quadrats at each of five altitude gradients (2000, 2200, 2400, 2600, and 2800 m). By measuring morphological and nutrient indicators in leaves from five individuals of Quercus rehderiana in each quadrat, we analyzed the response of leaf functional traits to elevation. The results showed that leaf thickness (LT), specific leaf area (SLA), phosphorus (P), potassium (K) concentrations, carbon phosphorus ratio (C:P ratio), and nitrogen phosphorus ratio (N:P ratio) of Quercus rehderiana varied significantly across different elevations. Regression analysis revealed that leaf area (LA), K concentration, and carbon nitrogen ratio (C:N ratio) decreased with increasing elevation, while LT and nitrogen (N) concentration increased. Correlation analysis indicated that LA was significantly negatively correlated with LT and leaf P concentration, but positively correlated with carbon (C) concentration and stoichiometric ratios (C:N, C:P, N:P). Leaf thickness (LT) was significantly negatively correlated with K and calcium (Ca) concentration. Specific leaf area (SLA) and K concentration were significantly negatively correlated with leaf dry matter content (LDMC). The leaves of Quercus rehderiana mainly adapt to different elevations through trade-offs among different morphological and chemical traits. These findings can support the conservation of germplasm resources and forest management.

Ecological stoichiometry, as a discipline investigating plant elemental coupling mechanisms, has become a research focus across various ecosystems. However, few studies have examined plant stoichiometric characteristics in the water–land ecotone of plateau karst lake wetlands. It remains unclear whether foliar nutrient contents and stoichiometric ratios in this transitional zone vary with flooding intensity. This study established three sampling gradients (near-water area, middle area, and far-water area) within the water–land ecotone of Caohai Lake wetland in Guizhou Plateau, measuring nutrient concentrations along with their stoichiometric ratios in leaves of three dominant plant species. The results revealed significant interspecific differences in leaf nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) concentrations and N:P ratios among the three dominant species, while significant spatial variations were observed in N concentration and the C:N ratio across sampling locations. Correlation analysis demonstrated significant positive relationships among leaf N, P, and K concentrations, all showing negative correlations with C concentration. Phragmites australis exhibited significantly lower C:N and N:P ratios compared to Scirpus validus and Juncus effusus, suggesting its growth advantage through rapid nutrient acquisition. This species may serve as an efficient phytoremediator for N and P absorption from both soil and water. These findings provide valuable references for vegetation selection in constructed wetlands.

Carbon (C), nitrogen (N), and phosphorus (P) stoichiometry serves as a crucial indicator of interconnected biogeochemical cycles in terrestrial ecosystems, influencing nutrient limitation patterns, elemental balance and coupling, as well as plant adaptation strategies to environmental constraints. However, the interaction mechanisms between plants and soils in karst rocky desertification forests remain poorly understood. This study comparatively analyzes the C, N, and P stoichiometric characteristics of Quercus rehderiana in both rocky and non-rocky desertification forests, aiming to elucidate the nutrient allocation strategies and element coupling mechanisms within rock desertification forest ecosystems. Five 20 m × 20 m plots were respectively established in rocky desertification and non-rocky desertification Quercus rehderiana forests, and each plot was further divided into four subplots of 10 m × 10 m. From three subplots closest to the center, we collected leaf, branch, fine root, litter, and soil samples and measured C, N, and P concentrations. The results showed that non-rocky desertification forests exhibited significantly higher P concentrations compared to their rocky desertification counterparts. Conversely, rocky desertification forests showed notably higher C: N and C: P ratios in all plant organs (leaf, branch, root) and litter. The N and P concentrations in Quercus rehderiana were higher in leaves and litter than in branches, which in turn were higher than in roots. The C: N and C: P ratios exhibited the opposite trend, with values following the order: roots > branches > litter and leaves. In rocky desertification forests, P concentration was significantly negatively correlated with the C: N, C: P, and N: P ratios across plant organs, litter, and soil, suggesting a strong coupling mechanism among these biogeochemical indicators. This research elucidates the C: N:P stoichiometric characteristics of the Quercus rehderiana plant-litter-soil system across varying rocky desertification habitats. Multivariate analysis indicated that forests in rocky desertification areas maintained strong soil nutrient coupling, whereas non-rocky desertification forests exhibited more pronounced litter decomposition-mediated nutrient coupling. These findings provide important insights for ecological restoration and vegetation management in rocky desertification regions.

Plant functional traits serve as vital tools for understanding vegetation adaptation mechanisms in changing environments. As the primary organs for nutrient acquisition from soil, fine roots are highly sensitive to environmental variations. However, current research on fine-root adaptation strategies predominantly focuses on tropical, subtropical, and temperate forests, leaving a significant gap in comprehensive knowledge regarding fine-root responses in rocky-desertification habitats. This study investigates the fine roots of Pseudotsuga sinensis across varying degrees of rocky desertification (mild, moderate, severe, and extremely severe). By analyzing fine-root morphological and nutrient traits, we aim to elucidate the trait differences and correlations under different desertification intensities. The results indicate that root dry matter content increases significantly with escalating desertification severity. Fine roots in mild and extremely severe desertification exhibit notably higher root C, K, and Mg concentrations compared to those in moderate and severe desertification, while root Ca concentration shows an inverse trend. Our correlation analyses reveal a highly significant positive relationship between specific root length and specific root area, whereas root dry matter content demonstrates a significant negative correlation with elemental concentrations. The principal component analysis (PCA) further indicates that the trait associations adopted by the forest in mild- and extremely severe-desertification environments are different from those in moderate- and severe-desertification environments. This study did not account for soil nutrient dynamics, microbial diversity, or enzymatic activity—key factors influencing fine-root adaptation. Future research should integrate root traits with soil properties to holistically assess resource strategies in rocky-desertification ecosystems. This study can serve as a theoretical reference for research on root characteristics and adaptation strategies of plants in rocky-desertification habitats.