A newly recorded drought-tolerant terrestrial cyanobacterium, Oculatella ucrainica Oxana Vinogradova & Tatiana Mikhailyuk, originally isolated from soil crusts and coastal areas in 2017, is reported in China for the first time. In this study, two filamentous cyanobacteria were isolated from moist soil at Taiyuan Normal University, Shanxi Province, and damp walls in Huaxi Park, Guizhou Province. These strains displayed morphological similarities to O. ucrainica, both featuring orange spots on the apical cells of their trichomes. Phylogenetic analysis based on 16S rRNA gene sequences demonstrated high similarity (above 99%) between the two isolates and O. ucrainica, with both strains clustering on a single branch with high bootstrap support. Furthermore, the secondary structure of these cyanobacteria closely resembled that of O. ucrainica, further corroborating their identification as members of this species. This study represents the first report of O. ucrainica in China.

Cycads, the oldest living seed plants, are primarily distributed in tropical and subtropical regions and are critically endangered. Comparative analysis of leaf traits between tropical-subtropical gymnosperm cycads and woody angiosperms offers valuable insights into the ecological strategies of cycad species. This study measured the morphological, anatomical, and hydraulic characteristics of leaves (pinnae) from 28 cycad species in the Nanning Botanical Garden. In addition, leaf traits of 79 tropical-subtropical forest tree species were compiled for comparative analysis. Results showed that: (1) Compared to angiosperms, cycads exhibited thicker leaves, higher saturated water content (SWC), stronger resistance to water loss (Ψ_tlp), and lower specific leaf area (SLA) and stomatal density (SD). However, the differences in leaf tissue thickness (MT) between the two taxa were not significant. (2) The network edge density (ED) of leaf traits in angiosperms was significantly higher than in cycads, while angiosperms showed lower network diameter and average path length. This indicates stronger correlations among angiosperm traits, facilitating more efficient resource utilization in tropical and subtropical environments. (3) Unlike angiosperms, SLA and Ψ_tlp in cycads were decoupled from SWC, suggesting that cycads rely more on water uptake through root systems or storage in stems rather than fine-tuning leaf physical properties for water regulation. This study highlights the variability and diversity of adaptive strategies across plant taxa and provides insights into the unique ecological adaptations of cycads in tropical and subtropical environments.

Leaf phenotypic variation among 10 populations of three Polyspora species was analyzed using multiple comparisons, nested variance analysis, correlation analysis, principal component analysis (PCA), and cluster analysis. Results revealed: (1) Significant differences in leaf phenotypic traits both within and among Polyspora populations (P<0.01). The average coefficient of variation was 17.03%, with trait-specific variation ranging from 0.05% to 31.37%. Mean variance components for leaf traits were higher within populations (180.79) than among populations (82.63), indicating greater differentiation within populations. (2) Dominant contributors to phenotypic variation included leaf width, petiole length, leaf area, leaf base angle, leaf roundness, and petiole index. Significant correlations among leaf traits were identified, highlighting the strong influence of environmental factors on leaf phenotypic variation. Cluster analysis grouped the 10 populations into three distinct groups based on leaf phenotypic traits. The results provide valuable insights into the adaptive evolution and exploitation of Polyspora species.

Fruit trees, vital to global agriculture, depend heavily on pollinators to facilitate successful reproduction and ensure optimal yield. Microorganisms associated with anthers can influence pollen viability, and their community composition may be affected by pollinator activity. While understanding the diversity and community assembly patterns of these microorganisms has potential implications for enhancing the reproductive fitness of fruit trees, research in this area remains relatively scarce. This study employed high-throughput sequencing to analyze the diversity and community structure of fungi and bacteria on the anthers of loquat (Eriobotrya japonica (Thunb.) Lindl.) before (bagged group) and after (nature group) pollinator visitation. Results showed that pollinator visitation had no significant effect on the diversity or composition of anther microbiomes. In the bagged group, dominant fungal taxa included Cladosporiaceae and Mycosphaerellaceae, whereas Cladosporiaceae and Metschnikowiaceae were dominant in the nature group. Bacterial communities in both groups were also dominated by Alcaligenaceae and Erwiniaceae. These findings indicate that the microbial community composition within loquat anthers is inherently stable and largely unaffected by pollinator activity.

Based on a field survey conducted during the Third Xinjiang Scientific Expedition, this study compiled a comprehensive list of seed plants in the valley forests of the Irtysh River basin in Xinjiang and analyzed their floristic characteristics using floristic geography methods. Results identified 403 seed plants belonging to 55 families and 228 genera, representing 48.67%, 29.73%, and 10.84% of seed plant families, genera, and species in Xinjiang, respectively, highlighting rich plant diversity. Herbaceous plants dominated the flora, accounting for 80.40% of the total species, whereas tree species were relatively limited, with Salicaceae serving as the dominant constructive and characteristic family within the communities. Furthermore, shrubs were notably absent, representing an important aspect of the valley forests. Geographically, the families and genera were classified into seven and 25 distribution types, respectively, with 59.09% of non-cosmopolitan families and 92.90% of non-cosmopolitan genera exhibiting temperate distribution patterns. The interaction between plant species and environmental factors has resulted in transitional adaptations, including xerophytes and hyper-xerophytes suited to arid conditions and cold-adapted hygrophytes thriving in mountain forests and alpine meadows. These valley forests act as a crucial regional species pool with significant conservation value. Moreover, the study also revealed that valley forests can be classified as piedmont or mountain according to community composition, dominant tree species, topography, and geomorphology.

Cupressus gigantea W. C. Cheng & L. K. Fu, a tree species endemic to Tibet and classified as a national first-class protected species in China, requires clear delineation of its potential suitable distribution for effective conservation, introduction, and breeding programs. This study established the MaxEnt model, using the “kuenm” R package to optimize model parameters, to predict the potential distribution of C. gigantea across China. Environmental variables influencing distribution were analyzed through percent contribution and Jackknife tests. The optimized model demonstrated superior predictive accuracy and reduced complexity compared to the default parameter model. Key factors influencing the distribution of C. gigantea included distance from rivers, temperature seasonality, isothermality, slope, and precipitation during the coldest quarter. Predicted suitable distribution areas were primarily located in Tibet and Sichuan, with the cities of Nyingchi, Lhoka, Lhasa, and Rikaze in Tibet encompassing the entirety of moderately suitable (2 298 km²) and highly suitable areas (746 km²). The high suitability area was exclusively distributed in Nyingchi (563 km²) and Lhoka (183 km²), representing about 0.062% of the total area of Tibet. The corridor between Lang County and Milin County emerged as the core habitat for C. gigantea, underscoring the need to prioritize conservation efforts in this critical region.

Based on regularly continuous observation data, this study applied the Richard growth model to analyze the growth dynamics of ground diameter (GD) and tree height (H) in plantations of four tree species, Pinus massoniana, Liquidambar formosana, Schima superba, and Elaeocarpus decipiens. Organ biomass allocation was quantified using the harvest method under consistent site conditions, soil characteristics, management measures, and stand ages. Results showed that: (1) The Richard growth model demonstrated excellent predictability and adaptability to the growth dynamics of GD and H across the four tree species plantations. Growth rates varied among species, with P. massoniana demonstrating the highest annual growth rates for GD and H, followed by S. superba, and surpassing those of L. formosana and E. decipiens in the 6th to 8th year. These differences became more pronounced with increasing stand age. Rapid GD growth in P. massoniana occurred earlier (3rd to 8th years) and lasted longer, with H entering its rapid growth phase by the 5th year. In contrast, rapid GD growth for L. formosana, E. decipiens, and S. superba was delayed by 1–2 years and shortened by 2–4 years, with S. superba showing a delayed rapid H growth period and L. formosana and E. decipiens failing to enter a rapid H growth phase. Notably, all species prioritized GD growth, especially P. massoniana. (2) Trunk biomass accounted for the largest proportion of total plant biomass (46.0%–58.8%), with L. formosana having the highest proportion. Leaf biomass contributed the least (3.0%–11.2%), with L. formosana showing the lowest share. Above-ground biomass (AGB) in P. massoniana was significantly greater than its below-ground biomass (RGB), while no significant difference was observed between AGB and RGB in three broad-leaved species. Furthermore, the three broad-leaved species exhibited higher RGB proportions (25.4%–27.6%) and root-to-shoot ratios (35.1%–40.6%) compared to P. massoniana. The biomass allocation in P. massoniana favored AGB, enhancing its competitiveness for above-ground space and light, thereby supporting rapid GD and H growth. In contrast, the distribution of AGB and RGB in the three broad-leaved trees was relatively balanced, resulting in slower GD and H growth rates, especially in E. decipiens, which exhibited well-developed root systems and strong competition for subsurface nutrients. In S. superba, AGB was preferentially allocated to branches and leaves, facilitating fast-growing characteristics, while in L. formosana, trunk biomass allocation promoted H growth. These results highlight the complementary advantages of mixed plantations. Pairing P. massoniana with S. superba enhances the cultivation of large-diameter timber, combining P. massoniana with L. formosana improves soil fertility, and integrating P. massoniana with E. decipiens optimizes resource utilization for sustainable growth.

Understanding how intertidal elevation influences the community characteristics and population dynamics of Bruguiera sexangula (Lour.) Poiret is essential for the effective conservation and sustainable management of mangrove ecosystems. This study investigated variations in community characteristics, age structure, spatial distribution pattern, static life-table parameters, and survival functions of B. sexangula along an intertidal gradient in the Hainan Dongzhaigang National Nature Reserve. Results showed the following key findings: (1) B. sexangula was the dominant species in the community. Species diversity, Pielou index, and stand density increased with increasing intertidal elevation, while the importance value, diameter at breast height, tree height, and crown width of B. sexangula decreased. (2) The spatial distribution pattern of B. sexangula exhibited significant clumping. The diameter distribution exhibited a convex-shaped pattern at low intertidal elevations and an inverted J-shaped pattern at both mid and high intertidal elevations. (3) Survival curves varied with intertidal elevation. Low intertidal zones exhibited a Deevey Type Ⅱ curve, while mid and high intertidal elevations showed Deevey Type Ⅲ curves. (4) The equilibrium points of survival and cumulative mortality functions occurred during the seedling stage across all intertidal elevations, and the magnitude of changes in the survival function curves at each intertidal elevation decreased after age Ⅴ. These findings demonstrate that intertidal elevation strongly affects the community characteristics and population dynamics of B. sexangula. This study provides critical baseline data for the protection and optimized management of mangrove ecosystems, particularly in regions experiencing dynamic intertidal changes.