Xishuangbanna Tropical Botanical Garden

Lianas are particularly abundant in seasonally dry tropical forests, where most species flower during the dry season. While hydraulic differences of vegetative organs between lianas and trees are well-documented, floral hydraulic strategies and their potential role in liana expansion remain unclear. To characterize divergence in floral water-use strategies between lianas and trees, we examined 24 floral traits related to water transport, storage, drought tolerance, and pollinator attraction in 16 liana and 16 tree species of Bauhinia s.l. from a tropical seasonal rainforest in Yunnan, China. Liana flowers exhibited greater petal vein density, stomatal density and size, flower mass per area, and drought tolerance than tree flowers, which showed higher saturated water content and hydraulic capacitance. Liana flowers exhibited a trade-off between hydraulic efficiency and safety, but trees did not. Life forms also differed in trait coordination linking hydraulic structure, function, and reproduction. Our findings reveal divergent floral hydraulic syndromes: lianas adopt structurally reinforced, drought-tolerant designs for canopy flowering under high vapor pressure deficit, while trees rely on internal water reserves to buffer water loss. This study provides the first organ-level evidence that divergent floral hydraulic strategies underpin reproductive success and may help explain liana dominance in seasonally dry tropical forests under climate change.

Tree species differ in how they acquire nutrients through arbuscular mycorrhizal fungi (AMF) and ectomycorrhizal fungi (EMF) symbioses, yet how these contrasting mycorrhizal strategies regulate soil microbial nutrient mobilization and its coupling to tree nutrient status remains poorly resolved. Here, using a 10-year temperate tree diversity experiment, we quantified soil microbial community structure, phospholipid fatty acid (PLFA)-derived carbon (C) sources tracing, ecoenzymatic stoichiometry, and foliar nutrient pools to test how tree diversity and mycorrhizal type control the linkage between soil microbial nutrient acquisition and foliar nutrient pools. We found that the tree mycorrhizal type exerted a dominant control on microbial community structure. AMF-associated tree mixtures (plots dominated by AMF tree species) were characterized by saprotrophic Ascomycota, which exhibited a higher contribution of root-derived C to fungal biomass, whereas EMF-associated mixtures were dominated by symbiotrophic Basidiomycota that relied more strongly on detritus-derived C. Ecoenzymatic strategies diverged consistently with these contrasting C acquisition pathways. AMF-associated soils exhibited higher C-acquiring enzyme activity and a greater vector length (an index of microbial C acquisition investment), indicating stronger microbial investment in C acquisition from soil organic matter. In contrast, EMF-associated soils exhibited lower vector angles (indicating relative microbial investment in nitrogen versus phosphorus acquisition) and significantly higher nitrogen (N)-acquiring enzyme activity, reflecting enhanced microbial N acquisition. Across all tree mixtures, fungal community composition was tightly linked to ecoenzymatic stoichiometry, and both were significantly associated with foliar N pools. Partial least squares path modelling revealed that mycorrhizal type influenced foliar N pools primarily through indirect pathways contributed by fungal community structure and microbial N-acquisition strategy. Together, these results demonstrate that mycorrhizal type governs how soil microbes channel C from the tree into N mobilization pathways, thereby regulating the strength of belowground–aboveground N coupling. Our findings reveal a mechanism by which mycorrhizal associations, rather than tree diversity alone, shape soil microbe–tree interactions in temperate forest ecosystems.

Abstract Tea ( Camellia sinensis ) cultivation, central to global agriculture and livelihoods, is increasingly challenged by soil degradation, heavy metal contamination, and climate stressors largely driven by intensive practices. Because tea agroecosystems typically occupy acidic, nutrient-poor soils, sustainable management is essential. Biochar, a carbon (C)-rich product of biomass pyrolysis, has emerged as a promising amendment to restore soil health, mitigate contaminants, and strengthen crop resilience. This review synthesizes recent advances on the biochar–soil–tea nexus across five dimensions: (i) soil physicochemical and structural properties, (ii) microbial diversity and functions, (iii) nutrient mobilization and efficiency, (iv) tea productivity and quality, and (v) heavy-metal detoxification. Evidence from field and controlled studies shows that biochar can buffer soil acidity, enhance nutrient retention, restructure microbial communities, reduce pollutant bioavailability, and improve tea growth and quality. In addition, it offers a practice guide for tailoring biochar application based on feedstock and pyrolysis conditions to achieve specific soil and plant health goals. Furthermore, biochar contributes to C sequestration and greenhouse gas mitigation, situating its use within the broader framework of climate-smart agriculture. Despite these benefits, outcomes are highly context-dependent, shaped by feedstock type, pyrolysis conditions, soil characteristics, and application rate. Critical research gaps remain, including scarce tropical field studies, limited long-term field evaluations, inconsistent biochar characterization, and insufficient understanding of cultivar-specific and microbial interactions. By mapping these uncertainties and outlining research priorities, this review provides a foundation for optimizing biochar use in tea systems and guiding region-specific strategies for sustainable cultivation in a changing climate.

Sacha inchi ( Plukenetia volubilis L.), a perennial oilseed crop native to the Andean tropics, is increasingly cultivated in China for its omega-rich seeds. However, the increasing incidence of root rot, primarily caused by Fusarium oxysporum , poses a significant threat to its productivity and industry viability. The study aimed to evaluate the effects of different cultivation practices—including soil amendment, intercropping, and mulching—on soil health, root disease incidence, and the yield of Sacha inchi under tropical field conditions. A three-year randomized block field experiment (2020–2023) was conducted to test five treatments: S1 (monoculture control), S2 (intercropping with soybean), S3 (quicklime sterilization of planting holes and topsoil;), S4 (sulfur fertilization), and S5 (plastic film mulching). Among all treatments, quicklime application (S3) produced the most significant improvements. It reduced abundance of Fusarium , and root rot incidence (44.44 %) compared to the control (77.78 %) and enhanced soil pH, increased exchangeable calcium (Ca) and magnesium (Mg), and reduced exchangeable aluminum (Al). Yield under S3 (6065.4 kg ha –1 ) was 48.99 % higher than the control (S1), and notably higher than all other treatments. However, S3 also reduced soil-available copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe). Overall, our results demonstrate quicklime application to planting holes and topsoil is a practical strategy to manage root rot and boost Sacha inchi productivity in tropical cropping systems, thereby ensuring the sustainable development of the Sacha inchi industry. Quicklime sterilization of planting holes and topsoil layers significantly enhanced Sacha inchi yield. • Lime sterilization significantly increased Sacha inchi yield under tropical field conditions. • Liming reduced the abundance of Fusarium in the soil and lowered root rot incidence. • Liming improved soil pH and increased exchangeable calcium and magnesium levels. • Liming depleted soil micronutrient, suggesting the need for supplementation. • Lime sterilization is a promising strategy for managing soil-borne disease and enhancing Sacha inchi productivity.

Understanding spatial and seasonal variations in leaf stoichiometry is essential for understanding plant nutrient-use strategies and their implications for ecosystem biogeochemical cycling. Although broad-scale stoichiometric patterns have been well documented for terrestrial plants, comparable evidence for vascular epiphytes remains limited. Here, we examined spatial and seasonal variation in leaf stoichiometry of vascular epiphytes by integrating field data from subtropical and tropical forests in southwestern China with a global literature synthesis. At the global scale, leaf nitrogen and phosphorus concentrations (LNC and LPC) of vascular epiphytes were significantly related to climate variables, whereas no clear latitudinal pattern was detected for leaf N:P ratios. At the regional scale, vascular epiphytes in the subtropical montane moist forest exhibited higher LNC and LPC and lower C:N and C:P ratios than those in the tropical seasonal rainforest. At the local scale, LPC of epiphytes was positively correlated with host LPC, whereas LNC showed a weak but statistically significant association with N availability in canopy soils. Seasonally, evergreen epiphytes exhibited higher leaf nutrient concentrations during the rainy season, and deciduous species showed significantly higher stem N, P, and K concentrations during the dry season, indicating contrasting seasonal nutrient-use strategies. Our results demonstrate that leaf stoichiometry of vascular epiphytes is jointly shaped by climate, canopy-level nutrient dynamics, and seasonal regulation, and differs fundamentally from patterns commonly observed in terrestrial plants. These findings highlight the importance of considering canopy-specific processes and fine-scale species turnover when assessing large-scale stoichiometric patterns and forest nutrient cycling.

Heterostemma tongbiguanense (Apocynaceae), a new species from Yunnan Tongbiguan Provincial Nature Reserve, Yunnan Province, China, is described and illustrated. It is similar to H. cucphuongense T. B. Tran & Rodda and H. tanjorense Wight & Arn.; morphological differences are mainly in the stems and leaves with densely brown-yellow tomentose, corona apically serrated, below middle are papillae on both sides. Photographs, distribution, comparison with related species, and a conservation assessment are provided for this rarely observed species.

Abstract All plant organs have the potential to harbor microbial communities and each organ may form unique niches for specialized microbial communities. There have been very few detailed investigations of microbiomes within a single plant organ along different developmental stages. Here, we investigated the bacterial and fungal communities associated with the endosphere and rhizoplane of primary aerial roots, mature aerial roots, and subterranean parts of mature aerial roots of Cissus verticillata . Our results showed that the proportions of dominant bacterial and fungal genera varied across the three aerial root types both for the endosphere and for the rhizoplane. For the endosphere bacteria, the highest diversity indices were observed in subterranean aerial roots, while mature aerial roots had a higher rhizoplane bacteria diversity. For fungal diversity indices, mature aerial roots had the highest richness for both endosphere and rhizoplane fungi. The study also found that the microbial assemblage composition of each aerial root type was distinctly unique. Generally, our network analysis revealed that fungi had higher network property values compared to bacteria. Additionally, the rhizoplane had higher network property values than the endosphere, particularly within the fungal community. Furthermore, bacterial functions were similar across the three aerial root types, which suggests the stability of bacterial functions. By contrast, considerable shifts in the relative abundance of fungal functional groups across aerial root development were observed. Additionally, fungi and bacteria show differential responses to three aerial root types. This study provides a new perspective for understanding the characteristics of plant aerial root microbial communities along developmental stages.

Vegetation carbon turnover time (τveg) dominates the uncertainty in terrestrial carbon cycle dynamics. Reports have shown that the τveg of mature or old-growth forests in North America and Europe has decreased because of faster carbon loss under global climate change. However, the temporal trend of τveg in widespread younger forests, which exhibit different growth patterns, remains inconclusive. Here, we consistently revealed a significant overall increase in τveg (0.025±0.002years per year) across China's forests that are characterized by a relatively young forest age structure, using multisource data-model assimilation and long-term network observations. In young forests that receive high nitrogen deposition, increasing levels of CO2 accelerate vegetation growth, causing it to grow faster than it dies or decomposes, leading to increases in the τveg. The effects of forest age on τveg dynamics and the high sensitivity of enhanced carbon sinks to τveg should be incorporated into future land surface models to ensure that the τveg dynamics and their impacts on terrestrial carbon cycling and climate mitigation are accurately assessed. Our results also provide valuable insights for forest management aimed at enhancing carbon retention and sequestration through optimizing age-related stand dynamics.