XTBG OpenIR

New Plio-Pleistocene flora from the Central Highlands of Vietnam-ancient analog of southern Indochina's tropical monsoon forests

2026-09-02T02:27:14Z

Title: New Plio-Pleistocene flora from the Central Highlands of Vietnam-ancient analog of southern Indochina's tropical monsoon forests Authors: Wang, Teng-Xiang; Liu, Jia; Wilf, Peter; Huang, Jian; Do, Truong Van; Nguyen, Hung Ba; Zhang, Shi-Tao; Su, Tao Description:

The biodiverse forests of southern Indochina face severe anthropogenic pressure, but understanding of their deep-time history remains limited due to the general lack of fossil evidence. Here, we present a new Plio-Pleistocene macrofossil flora from the ing 565 specimens of 44 morphotypes. The assemblage is dominated by dicotyledonous leaves with well-preserved venation or cuticles and is characterized by entiremargined leaves (with only one toothed morphotype) and relatively small leaf sizes (87% microphylls and notophylls). The flora, in rank order, has abundant Syzygium paceae) leaves, along with potential representatives from Fabaceae, Lauraceae, Phyllanthaceae, and Lecythidaceae. Both leaf physiognomy and floristic composition indicate that the Kon Tum flora represents a lowland seasonal tropical broad-leaved forest linked to extant regional forests. The diverse associated palynoflora supports this paleovegetation interpretation with mixed source environments and indicates a Pliocene to early Pleistocene age of deposition in a coastal, fluvial setting with tidal influence. The study site is currently at an elevation of over 500 m, indicating significant uplift since deposition. This study marks the first Cenozoic paleobotanical collection of southern Indochina and presents an ancient analog of the extant regional lowland monsoon forests, one of the world's most threatened forest ecosystems.

Tight regulation of Earth's long-term temperature over Phanerozoic time

2026-09-02T02:23:37Z

Title: Tight regulation of Earth's long-term temperature over Phanerozoic time Authors: Zheng, Dongyu; Lipp, Alex G.; Farnsworth, Alexander; Li, Shufeng; Merdith, Andrew S.; Gurung, Khushboo; Hou, Mingcai; Chen, Anqing; Hou, Zixi; Lunt, Daniel J.; Sperling, Erik A.; Valdes, Paul J.; Mills, Benjamin J. W. Description: Knowing the past temperature of the Earth is crucial for understanding the mechanisms driving climate change and biosphere evolution, but there is significant debate about the range of past temperature variation. Previous interpretations, largely based on oxygen isotope records, suggest that global temperature has generally declined over the past 539 million years, but substantial uncertainties persist. In this study, we introduce an independent estimate for long-term Phanerozoic temperature trends based on a large database of chemical weathering indices from siliciclastic sedimentary rocks, globally upscaled using a state-of-the-art general circulation paleoclimate model. Our results imply that Phanerozoic global temperatures remained within 10-30 degrees C, and that Paleozoic oceans had comparable temperatures to Mesozoic and Cenozoic oceans, in contrast to previous work suggesting that they were anomalously hot. This finding supports the idea that negative feedback processes, such as silicate weathering, have maintained long-term global average temperatures within a relatively tight range, contributing to the continued long-term evolution of the biosphere.

The 'stemness' trait in recalcitrant seeds of Garcinia xanthochymus is modulated by hormonal balance

2026-09-02T02:23:24Z

Title: The 'stemness' trait in recalcitrant seeds of Garcinia xanthochymus is modulated by hormonal balance Authors: Wen, Bin; Yang, Lan; Wang, Ruling; Chen, Ligang; Yang, Xiangyun; Pritchard, Hugh W. Description: Garcinia seeds have an unusual seedling regeneration trait involving Garcinia-type germination and totipotent germinability, i.e., 'stemness'. These regeneration traits are regarded as an adaptation to animal predation; however, their cellular, physiological and hormonal bases are largely unexplored. We used Garcinia xanthochymus seeds to investigate the morphological, cytological and metabolomic basis of seeds and seed fragments using diverse methods. Irrespective of the orientation of the seeds or seed segments on sowing, the shoot always emerged from the proximal region and primary root from the distal end. Likewise, no matter how the explants were inoculated in vitro, shoots emerged only from the proximal edge of the seed slices. These regeneration patterns indicated that the Garcinia xanthochymus 'stemness' trait has a clear root-shoot polarity even though the seed lacks clearly differentiated components of axis and cotyledon, based on our morphological and cytological investigations. The seeds contain diverse and abundant plant growth regulators, especially auxins, cytokinins and GAs, and these hormones exhibit concentration gradients across the distal, middle and proximal parts of the seeds. The whole seeds are composed of living cells with active metabolism, as indicated by the TTC test, and callus could grow over all cut surfaces (distal-, proximal-, transversely-, longitudinally-, horizontally-cut) except those in contact with the medium when incubated on MS medium without exogenous hormones. These results suggest that much of the 'seed' tissue has endogenous hormone levels sufficient for cell division and morphogenesis, enabling seeds to exhibit totipotency in response to physical damage.

How does plant diversity drive productivity in China's drylands: Through complementary or mass ratio effects?

2026-09-02T02:28:19Z

Title: How does plant diversity drive productivity in China's drylands: Through complementary or mass ratio effects? Authors: Guo, Hao; Meng, Hong-Hu; Yin, Jin-Fei; Li, Tong; Yin, Ben-Feng; Zhou, Xiao-Bing; Zhang, Yuan-Ming Description:

Dryland biodiversity-productivity relationships remain poorly resolved. Specifically, the environmental conditions governing the shift between complementarity and mass ratio mechanisms remain unclear, limiting the effectiveness of restoration and management strategies. To address this gap, the aim of this study was to investigate the geographical patterns of diversity and biomass production in herbaceous communities along a 2100-km precipitation gradient in North China. We studied how alpha- and beta-diversity affect community-wide productivity using linear mixed-effects models and piecewise structural equation models, along with rolling-window change-point analyses. In arid regions, biomass productivity was primarily driven by interspecific niche complementarity, where higher functional diversity (FD(alpha)) enhanced resource-use efficiency. However, in semi-arid regions, productivity was regulated by the mass ratio effect, specifically through the traits of dominant species, including community weighted mean height and specific leaf area, as these species exploited broader resource spectra with increasing water availability. A critical mechanistic shift occurred at a mean annual precipitation (MAP) threshold of similar to 168 mm (95% CI: 152-171 mm; p < 0.001). Below this threshold, productivity was driven by diversity-mediated complementarity and stress tolerant strategies. Conversely, as MAP surpassed 168 mm, the system transitioned to mass ratio control, coincident with a shift toward competitive strategies. Overall, our study provides empirical evidence to guide dryland management: prioritising the maintenance of functional diversity in arid communities, while emphasising dominant-trait optimisation (plant height and specific leaf area) in semi-arid communities to maximise aboveground biomass. (c) 2026 Kunming Institute of Botany, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Naturalist Identity and Biodiversity Conservation: The Mediating Role of Obligation

2026-09-02T02:28:49Z

Title: Naturalist Identity and Biodiversity Conservation: The Mediating Role of Obligation Authors: Meng, Yichuan; Chen, Jin Description:

Identity is a fundamental concept in social psychology; however, its application in conservation education has been limited. This study examines the impact of naturalist identity on biodiversity conservation behaviors, focusing on both direct and indirect pathways mediated by a sense of obligation. Using a mixed-methods approach, we developed and validated a 10-item Naturalist Identity Scale (NIS) using a total of 824 valid responses from naturalists and college students, demonstrating strong psychometric properties and cross-group comparability. Results from 198 naturalists revealed that naturalist identity significantly predicts biodiversity-related actions, with a sense of obligation partially mediating this relationship. Consequently, the study provides a reliable scale for measuring naturalist identity and suggests that a stronger naturalist identity is associated with a higher frequency of biodiversity actions. Our findings emphasize the importance of identity in fostering conservation behaviors and offer practical insights for environmental education strategies.

A framework for urban planning of rapidly urbanized cities from the perspective of functional zoning

2026-09-02T02:22:51Z

Title: A framework for urban planning of rapidly urbanized cities from the perspective of functional zoning Authors: Ding, Tonghui; Fang, Liping; Chen, Junfei; Fang, Zhou; Yang, Xinze Description: Integrating functional zoning based on ecosystem service (ES) supply-demand into urban planning has received little attention. Therefore, a novel framework for urban planning in rapidly urbanized cities from the functional zoning perspective is presented. Here, urban functional zones are first delineated based on the ES supply-demand. Then, key urban functional zones are designated as restricted development zones to simulate land use structures under different urban planning schemes. Next, the supply, demand, and supply-demand relationship of ESs under different schemes are re-evaluated to analyze the simulation effects. Finally, the applicability and operability of this framework is demonstrated through a case study of Suzhou, China. The results showed that Suzhou is divided into five functional zones, three of which are set as restricted development zones in the scenario simulation of corresponding schemes. The supply-demand imbalance of ESs except for soil retention and food production is significantly alleviated under the ecological protection scenario, but is aggravated under the economic development scenario. The food security scenario improves the supply-demand balance of carbon storage and food production, while detrimentally affecting other ESs. Overall, different planning schemes have distinct impacts on the ecological security of rapidly urbanized cities.

Promoting Transboundary Water Cooperation Under Scarcity: The Role of Intergovernmental Regulatory Costs and Measures

2026-09-02T02:30:08Z

Title: Promoting Transboundary Water Cooperation Under Scarcity: The Role of Intergovernmental Regulatory Costs and Measures Authors: Wang, Weiwei; Zhang, Hengjie; Zhang, Muzi; Gu, Hongbin; Zhou, Lin; Yang, Xueqian; Chen, Changgao; Fang, Zhou Description:

In transboundary river basins, achieving spontaneous cooperation over water between upstream and downstream nations is often challenging due to conflicting interests under water scarcity, especially in the absence of intergovernmental water cooperation organizations (IWCOs). Existing studies frequently assume IWCOs act as strong reciprocators, yet they often overlook the associated regulatory costs, as well as the coexistence of conflict and cooperation among riparian countries. This study develops a tripartite game model that incorporates upstream nations as water suppliers, downstream nations as water users, and an IWCO as the regulator. By integrating factors such as water supply benefits, water utilization benefits, speculative gains, and regulatory measures, the model is applied to the Lancang-Mekong River Basin. The results indicate that: First, the IWCO acts as a cost-sensitive catalyst; high supervision costs may lead it to adopt weak regulation, yet cooperation can still spontaneously emerge when driven by sufficient shared interests. Second, conflict and cooperation are not mutually exclusive but co-evolve across distinct phases; early-stage conflict acts as a functional signal triggering necessary intervention, which eventually transitions into stable cooperation sustained by later-stage benefit-sharing. Third, stability is threatened by speculative micro-conflicts, which can be suppressed through a precise mechanism combining targeted penalties and incentives. This study provides a structured framework for achieving sustainable transboundary water management.

Assessing the impacts of ecotourism on perceived ecosystem services and livelihoods: a case study in the Hani Terraces, China

2026-09-02T02:30:45Z

Title: Assessing the impacts of ecotourism on perceived ecosystem services and livelihoods: a case study in the Hani Terraces, China Authors: Huang, Zhongde; Fu, Degui; Ali, Maroof; Ma, Zhengchang; Li, Mei; Luo, Xiong; Xu, Anjian; Bai, Yang Description:

Ecotourism concerns ecosystem services and the well-being of both people and nature and is vital for promoting sustainable livelihoods in mountain communities globally. However, ecotourism often involves trade-offs and conflicts between development and conservation, requiring stakeholders to seek effective synergies. This empirical study examines ecotourism-induced changes in ecosystem services in the Hani Rice Terraces area of China and their economic and conservation impacts on local communities, drawing on 229 valid questionnaire responses regarding residents' livelihood perceptions. The results show that local ecosystem services linked to residents' livelihoods such as nutrient cycling, food supply, natural education, flood regulation, and disease and pest control were highly synergistic with the economic improvement brought about by ecotourism. In contrast, two ecosystem services (biodiversity and air quality) demonstrated near-significant trade-offs. However, a significant disparity was observed between local economic growth and the direct economic benefits accruing to residents from ecotourism, with less than 20% of household income primarily derived from ecotourism activities. Structural equation modeling analysis further indicated that while residents exhibited strong conservation willingness through their perceptions of ecosystem services, these perceptions did not indirectly influence conservation willingness via economic development or personal income. These findings suggest that although the current ecotourism model has contributed to economic growth, it may undermine residents' livelihoods and erode ecological culture rooted in the harmonious coexistence of people and nature. This divergence could threaten the sustainability of regional tourism development and ecosystem management. Therefore, we recommend that decision-makers develop stronger collaborative synergies and implement payment for ecosystem services schemes to better balance economic and ecological benefits for future sustainable management.

The transcription factor OsWRKY36 regulates leaf angle in rice by modulating brassinosteroid signaling

2026-09-02T02:31:12Z

Title: The transcription factor OsWRKY36 regulates leaf angle in rice by modulating brassinosteroid signaling Authors: Zhao, Lirong; Yu, Jianyuan; Chen, Shidie; Liu, Lei; Li, Xia; Chen, Wanqin; Xu, Zhiyu; Pan, Xingchen; Zhou, Wenyi; Chen, Ligang; Yu, Diqiu; Wang, Houping Description:

WRKY transcription factors orchestrate diverse responses to environmental stimuli in plants. Although considerable research has been conducted on the stress resistance mechanisms associated with WRKYs, little is known about the roles of WRKYs in regulating plant growth and development. Here, we identified OsWRKY36, a key regulator of rice (Oryza sativa) leaf angle and plant architecture, from a rice oswrky mutant library. OsWRKY36 is strongly expressed in the leaf lamina joint and promotes cell growth and expansion in adaxial parenchyma cells, leading to an increased leaf angle. A mechanistic investigation revealed that the E3 ubiquitin ligase OsPUB24, a negative component of brassinosteroid (BR) signaling, interacts with OsWRKY36 and facilitates its ubiquitination and degradation. Genetic evidence indicated that OsWRKY36 acts downstream of OsPUB24 to regulate the BR-induced increase in leaf angle. Furthermore, OsWRKY36 physically interacts with DWARF AND LOW-TILLERING (DLT), a positive regulator of BR, and cooperatively activates the expression of the BR-responsive gene OsBZR4. BR signaling stabilizes OsWRKY36 by inhibiting OsPUB24, allowing accumulated OsWRKY36 to interact with DLT and drive OsBZR4 expression, thereby positively regulating leaf inclination. Collectively, our study elucidates the mechanism underlying the regulation of leaf inclination and plant architecture by the BR-OsPUB24-OsWRKY36 and DLT-OsWRKY36-OsBZR4 modules. These findings not only advance the understanding of BR-mediated growth regulation but also offer a potential strategy for optimizing crop architecture through modulation of BR signaling. Brassinosteroids (BR) trigger the breakdown of an E3 ubiquitin ligase, allowing a transcription factor to accumulate and then activate BR-responsive genes, thereby controlling the leaf angle in rice.

Containment and phytoremediation: Complementary roles of vertical plant diversity for heavy metals mitigation in mining areas

2026-09-02T02:31:59Z

Title: Containment and phytoremediation: Complementary roles of vertical plant diversity for heavy metals mitigation in mining areas Authors: Rao, Jiangbo; Ahmad, Zeeshan; Zhang, Wenfu; Zhao, Jianli; Liu, Jinyang; Yang, Jie Description:

Despite decades of mining-driven pollution, the integrated role of vertical plant diversity in mitigating heavy metal risks remains insufficiently explored. Heavy metals (HMs) from mining pose significant environmental risks, with their sources and mitigation by vegetation at Southwest China's mines. This study investigated the sources and environmental risks of HMs in soils surrounding lead-zinc, manganese and limestone mines at the Southwest China and the mitigating role of vertical vegetation in controlling HMs. Manganese mining (24.2%), lead-zinc mining (22.9 %), agriculture plus oil combustion (17.4 %) and limestone mining (11.4 %) were dominant HM sources, accounting for 96 % of total concentrations. Degree of contamination (C-deg), pollution load index (PLI) and potential ecological risk index (PERI) revealed that soils in affected areas exhibited considerable to very high contamination and ecological risks along with significant declines in soil quality. Our findings demonstrate that natural vegetation significantly reduces contamination and ecological risks in vegetated areas ( p < 0.05). The high diversity of plants in different vertical layers plays a complementary role in mitigating soil HMs contamination. More diverse tree species can effectively block the spread of HMs, while more diverse herbaceous plants can effectively remediate multiple soil HMs contamination. Vegetated soil exhibited approximately 3.5-fold lower C-deg and significantly reduced PERI ( p < 0.05) as compared to adjacent bare soils. These results highlight the importance of native vegetation as a sustainable strategy for mitigating the soil HMs environmental risks of mining activities and the importance of conserving plant diversity in different layers.