Qinghai-Tibet Plateau Region Research Articles

Soil moisture content-based analysis of terrestrial ecosystems in China: Water use efficiency of vegetation systems

Water is a prerequisite for the formation of earth-biochemical-ecological systems. Differences in the spatial and temporal distribution of water resources are important factors in the formation of differences in the distribution of vegetation in terrestrial ecosystems and are key to the differences in vegetation productivity. Vegetation water use efficiency is calculated by the total amount of fixed biogenic carbon per unit mass of water consumed in photosynthesis and can be used to assess the intensity and capacity of an ecosystem to use water biomass. Based on remote satellite sensing data, this study proposes a new water use efficiency assessment model. The model was validated using flux site data, and we analyzed the relative contribution of climate factors to soil moisture use efficiency using a first-difference method. The results revealed the following: (1) The soil moisture use efficiencies (SUE) of remote sensing data inversions that were evaluated using flux site data based on correlation coefficients and Nash coefficients showed high reliability, and only the NMG (Inner Mongolia) station showed low correlation among the nine sites. (2) Among the nine agricultural sub-regions in China, only the SUE of the Qinghai-Tibet Plateau region showed a decreasing trend (−1.08 g C/m−2 kg H2O yr), while all other regions showed an increasing trend. (3) The highest vegetation soil moisture use efficiency (1.83 g C/m−2 kg H2O) was found in ferralisols, while the lowest vegetation SUE (0.17 g C/m−2 kg H2O) was found in arid soils. The SUE of different vegetation types showed the characteristics of forest > scrub > cultivated vegetation > wetland > grassland. (4) The relative contribution of gross primary productivity (GPP) to the change in SUE was 37.53%, while the relative contribution of soil moisture content to the change in SUE was −26.71%. Among the five climatic factors, temperature was the most dominant factor affecting the change in SUE, followed by precipitation, net radiation, leaf area index, and potential evapotranspiration. Revealing the relationship between terrestrial ecosystem GPP, soil moisture content, and their responses to climate factors is a prerequisite for understanding the adaptation strategies of regional terrestrial ecosystems to global climate change, which can help to inform decision-making for the sustainable development of ecosystems.

Assessment of Conservation Effectiveness of the Qinghai–Tibet Plateau Nature Reserves from a Human Footprint Perspective with Global Lessons

The intensity of human pressure (HP) has an important impact on the biodiversity and ecosystem services of nature reserves (NRs), and the conflict and the coordination between NRs and human activities are now key issues to solve in the construction of NR systems. This study improved and applied a human footprint (HF) model that considers population density, land use, night light, grazing intensity, and road construction as indicators of human activity to evaluate the effectiveness of NRs in the Qinghai–Tibet Plateau in mitigating HP from 2000 to 2020. The results indicated that during this period, the average HP in the national NRs of the plateau increased from 1.47646 to 1.76687, where values were generally high in the east and low in the west. The average value in wetland NRs was the largest and had the smallest growth rate, while that in desert NRs was the smallest and had the largest growth rate. From 2000 to 2020, the average HP in the core areas, buffer areas, and experimental areas of the NRs increased by 0.12969, 0.29909, and 0.44244, respectively. It is a challenge for the Chinese government to strengthen the ability of NRs to mitigate HP on the wetland reserves and experimental zones in the Qinghai–Tibet Plateau region.

Investigating the seasonal dynamics of surface water over the Qinghai–Tibet Plateau using Sentinel-1 imagery and a novel gated multiscale ConvNet

ABSTRACT The surface water in the Qinghai–Tibet Plateau (QTP) region has undergone dramatic changes in recent decades. To capture dynamic surface water information, many satellite imagery-based methods have been proposed. However, these methods are still limited in terms of automation and accuracy and thus prevent surface water dynamic studies in large-scale QTP regions. In this study, we developed a new fully automatic method for accurate surface water mapping by using Sentinel-1 synthetic aperture radar (SAR) imagery and convolutional networks (ConvNets). Specifically, we built a new multiscale ConvNet structure to improve the model capability in surface water body extraction. Moreover, a gating mechanism is introduced to promote the efficient use of multiscale information. According to the accuracy assessment, the proposed gated multiscale ConvNet (GMNet) achieved the highest overall accuracy of 98.07%. We applied our GMNet for monthly surface water mapping on the QTP; accordingly, we found that the QTP region experienced significant surface water fluctuations over one year. The surface water also showed distinct spatial heterogeneity on the QTP; that is, the surface water fraction of the Inner Tibetan Basin was significantly higher than that of the Mekong Basin in both the wet and dry seasons.

Does pollinator dependence decrease along elevational gradients?

Plants have long been thought to be less dependent on pollinators for seed production at higher elevations due to adverse pollination environments. However, recent research has yet to consistently support the generality of this expectation. In this study, we asked whether pollinator dependence decreases along an elevational gradient and how it varies with various reproductive traits. To answer these questions, we quantified pollinator–plant associations and various reproductive traits for 112 flowering plants spanning a large elevational gradient (990–4260 m a.s.l.) in the Qinghai-Tibet Plateau. We found that flowering plants in the Qinghai-Tibet Plateau region are highly dependent on pollinators for seed production (76.2% of seed production was contributed by animal pollinators and 44.6% of plants would produce no seed without pollinator visitation). Contrary to our expectation, there was no significant elevational gradient in pollinator dependence index. Although the pollinator dependence index was not significantly correlated with pollen limitation, flower size, floral longevity, or reward type, it was correlated with compatibility status and flowering time. These findings indicate that pollinator dependence does not decrease along an elevational gradient in the Qinghai-Tibet Plateau. Our study also highlights the severe vulnerability of flowering plant seed production to pollinator declines under global change in the Qinghai-Tibet Plateau region, particularly for early-flowering or self-incompatible plants growing at higher elevations (e.g., subnival belt).

Applications of CNOP-P Method to Predictability Studies of Terrestrial Ecosystems

In this paper, recent research on terrestrial ecosystem predictability using the conditional nonlinear optimal parameter perturbation (CNOP-P) method is summarized. The main findings include the impacts of uncertainties in climate change on uncertainties in simulated terrestrial ecosystems, the identification of key physical parameters that lead to large uncertainties in terrestrial ecosystem modeling and prediction, and the evaluation of the simulation ability and prediction skill of terrestrial ecosystems by reducing key physical parameter errors. The study areas included the Inner Mongolia region, north–south transect of eastern China, and Qinghai–Tibet Plateau region. The periods of the studies were from 1961 to 1970 for the impacts of uncertainties in climate change on uncertainties in simulated terrestrial ecosystems, and from 1951 to 2000 for the identification of the most sensitive combinations of physical parameters. Climatic Research Unit (CRU) data were employed. The numerical results indicate the important role of nonlinear changes in climate variability due to the occurrences of extreme events characterized by CNOP-P in the abrupt grassland ecosystem equilibrium state and formation of carbon sinks in China. Second, the most sensitive combinations of physical parameters to the uncertainties in simulations and predictions of terrestrial ecosystems identified by the CNOP-P method were more sensitive than those obtained by traditional methods (e.g., one-at-a-time (OAT) and stochastic methods). Furthermore, the improvement extent of the simulation ability and prediction skill of terrestrial ecosystems by reducing the errors of the sensitive physical parameter combinations identified by the CNOP-P method was higher than that by the traditional methods.

Landslide Detection Using Time-Series InSAR Method along the Kangding-Batang Section of Shanghai-Nyalam Road

Due to various factors such as urban development, climate change, and tectonic movements, landslides are a common geological phenomenon in the Qinghai–Tibet Plateau region, especially on both sides of a road, where large landslide hazards often result in traffic disruptions and casualties. Identifying the spatial distribution of landslides and monitoring their stability are essential for predicting landslide occurrence and implementing prevention measures. In this study, taking the Kangding-Batang section of Shanghai-Nyalam Road as the study area, we adopted a semi-automated time-series interferometric synthetic aperture radar (InSAR) method to identify landslides and monitor their activity. A total of 446 Sentinel-1 ascending and descending SAR images from January 2018 to December 2021 were thus collected and processed by using open-source InSAR processing software. After a series of error corrections, we obtained surface deformation maps covering the study area, and a total of 236 potential landslides were subsequently identified and classified into three categories, namely slow-sliding rockslides, debris flows, and debris avalanches, by combining deformation maps, optical images, and a digital elevation model (DEM). For a typical landslide, we performed deformation decomposition and analyzed the relationship between its deformation and rainfall, revealing the contribution of rainfall to the landslide. In addition, we discussed the effect of SAR geometric distortion on landslide detection, highlighting the importance of joint ascending and descending observations in mountainous areas. We analyzed the controlling factors of landslide distribution and found that topographic conditions are still the dominant factor. Our results may be beneficial for road maintenance and disaster mitigation. Moreover, the entire processing is semi-automated based on open-source tools or software, which provides a paradigm for landslide-related studies in other mountainous regions of the world.

The role of conventional tillage in agricultural soil erosion

Conventional tillage refers to the tillage process, especially the spring and autumn plowing process in which all the soil surface layer is disturbed, generally tilling approximately 20 cm deep. Conventional tillage is still widely used in sloping land, which leads to serious soil erosion and land degradation. The effect of tillage on soil erosion is defined by Tillage factor (T) in the model. The purpose of this study is to analyze the effect of conventional tillage on soil erosion and to calculate the value of the conventional tillage Factor T. The values of the conventional tillage factor (T value) were calculated for different soil and water conservation zones in China by collecting published literature and plot measurements from unpublished monitoring sites. The results showed that (1) the tillage factors of conventional tillage in China ranged from 0.27 to 0.55, with the largest being the North earth-stony region, the smallest being the Qinghai-Tibet plateau region, and the other six regions, namely, the Northeastern mollisol, the Northern wind erosion, the Northwest Loess Plateau, the South red soil, the Southwestern purple soil and the Southwestern karst region, were 0.34, 0.28, 0.53, 0.37, 0.35 and 0.29, respectively. In the regional soil erosion evaluation, the values can be taken by each of the eight main erosion type regions. (2) In the water erosion area except for the northeast, there is an obvious northsouth difference in the distribution of the T value, showing a decreasing trend from north to south. In practical use, the T value of the corresponding latitude area can be determined according to the Equation T = 0.2351φ- 0.02225, where φ is the latitude (°). (3) The T values of contour tillage, no-till, and monopoly tillage measures are significantly lower than the T values of conventional tillage, which have significant soil and water conservation benefits. The study initially determined the conventional tillage T values for each water conservation subzone, which can provide basic parameters for soil loss prediction on sloping land.

Threat of air pollution in the cleanest plateau

Threat of air pollution in the cleanest plateau

"The Yak"-A remarkable animal living in a harsh environment: An overview of its feeding, growth, production performance, and contribution to food security.

Yaks play an important role in the livelihood of the people of the Qinghai-Tibet Plateau (QTP) and contribute significantly to the economy of the different countries in the region. Yaks are commonly raised at high altitudes of ~ 3,000-5,400 m above sea level. They provide many important products, namely, milk, meat, fur, and manure, as well as social status, etc. Yaks were domesticated from wild yaks and are present in the remote mountains of the QTP region. In the summer season, when a higher quantity of pasture is available in the mountain region, yaks use their long tongues to graze the pasture and spend ~ 30-80% of their daytime grazing. The remaining time is spent walking, resting, and doing other activities. In the winter season, due to heavy snowfall in the mountains, pasture is scarce, and yaks face feeding issues due to pasture scarcity. Hence, the normal body weight of yaks is affected and growth retardation occurs, which consequently affects their production performance. In this review article, we have discussed the domestication of yaks, the feeding pattern of yaks, the difference between the normal and growth-retarded yaks, and also their microbial community and their influences. In addition, blood biochemistry, the compositions of the yaks' milk and meat, and reproduction are reported herein. Evidence suggested that yaks play an important role in the daily life of the people living on the QTP, who consume milk, meat, fur, use manure for fuel and land fertilizer purposes, and use the animals for transportation. Yaks' close association with the people's well-being and livelihood has been significant.

Sustainable Development Strategy of Ecotourism Marketing Based on New Media: A Case Study of Qinghai Tibet Plateau in China

At present, improving the ecological environment and green development has become the new concept and new normal of society. Ecotourism is a new tourism form and tourism development mode, which can not only meet the diversified needs of tourists for ecology, culture and tourism but also drive the development of the regional economy. The Qinghai Tibet Plateau is an important ecological barrier to the country, and its ecological strategic position is extremely important. Exploring how to promote regional economic development while protecting the ecological environment and reducing the negative impact of tourism activities is the key to the sustainable development of eco-tourism marketing in the Qinghai Tibet Plateau. Taking the Qinghai Tibet plateau region, which is rich in tourism resources and has a fragile ecological environment, as an example, based on the characteristic ecotourism resources of the Qinghai Tibet plateau region, this paper summarizes the existing problems and their causes and on this basis, discusses the implementation of active ecotourism marketing and sustainable development strategies in this region, with a view to exploring eco-friendly, green and low-carbon. The high-quality development road with plateau characteristics provides reference and reference.

Miocene Equisetum tubers from the Wulan Basin, Northeast Qinghai-Tibetan Plateau and their paleoecological significance

Equisetum fossils are often reported from the Cenozoic strata in the Northern Hemisphere, but their occurrence in the Qinghai-Tibetan Plateau (QTP) region is scarce. In this investigation, two new species of tuber fossils of Equisetum — Equisetum wulanense Zhang and Xie, n. sp. and Equisetum kekeense Zhang and Xie, n. sp. from the Miocene Youshashan Formation of the Wulan Basin, Qinghai Province are reported. The extant Equisetum plants are usually living in wet habitats. Therefore, fossil species, E. wulanense and E. kekeense, were likely to live in moist environments during Miocene too. The discovery of E. wulanense and E. kekeense in the late Middle Miocene (∼13.4 Ma) indicates that the local climate of the Wulan Basin was more favorable during this period. This new finding confirmed the previous view that the Neogene aridification in the northern QTP was varying: the climate in the Early Miocene and the Middle Miocene were relatively warm and humid and then the climate gradually became colder and drier since the Late Miocene. It is widely accepted that the uplift of the QTP intensified the trend of cooling and drying since the Late Miocene, and eventually formed a cold and dry climate pattern in the northeast margin of the QTP. The discovery of Equisetum fossils in this investigation improved our understanding on the Cenozoic diversity of Equisetum plants in the northern QTP, as well as on the paleoecological environments of the Wulan Basin in Miocene.

青藏高原牧区家庭能源消费对生态环境和人体健康的影响研究现状与展望

PDF HTML阅读 XML下载 导出引用 引用提醒 青藏高原牧区家庭能源消费对生态环境和人体健康的影响研究现状与展望 DOI: 10.5846/stxb202202190395 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（72174197，41901241，71904189）；第二次青藏高原综合科学考察研究项目（2019QZKK0304） Research status and prospect of household energy consumption impact on eco-environment and human health in the pastoral of Qinghai-Tibet Plateau Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:探究家庭能源消费对生态环境和人体健康的研究是系统推进家庭能源绿色低碳转型和实现联合国2030可持续发展目标的关键。重点综述了目前家庭能源消费、影响因素及其对生态环境和居民健康影响的国际研究现状。目前研究不足主要聚焦在以下两个方面：一方面，影响家庭能源消费因素的贡献率和影响消费行为的驱动机制尚不清晰；另一方面，目前主要针对家庭能源消费或者生态系统或者环境或者居民健康其中的某一方面或者某两个方面开展研究，鲜有研究系统的考虑家庭能源消费对生态环境和人体健康影响的综合研究。基于上述研究现状，结合青藏高原的实际情况，提出未来需要在宏观层面和微观层面加强研究。宏观层面：（1）亟需厘清青藏高原家庭能源与生态环境和人体健康之间的内在联系与驱动机制，形成青藏高原牧区"家庭能源-生态效应-环境效应-健康效应"的理论分析框架；（2）构建模块化的牧区"能源-生态-环境-健康-经济"等多学科交叉的综合评估模型，形成完整的、系统的评估方法。微观层面：（1）迫切开展青藏高原家庭能源消费特征与变化规律的研究；（2）深入开展家庭能源消费特征和变化规律与生态系统的反馈机制与量化研究；（3）加强牧区室内空气污染物浓度测定，丰富高寒地区室内污染物浓度数据以及人群暴露特征及其健康风险的研究。 Abstract:Exploring the household energy consumption and its impacts on eco-environment and human health is essential to promote the green and low-carbon transition of household energy system and achieve the 2030 United Nations Sustainable Development Goals. This paper presents a review on the state of the art for the domestic and international research on the factors that influencing the household energy consumptions and the impacts on eco-environment and residents' health. At present, particular attention should be given to the following two research deficiencies. On one hand, the contribution rate of factors that influencing the household energy consumption and the mechanism that driving the consumption behavior are not well understood; on the other hand, the comprehensive studies that systematically consider the correlations among household energy consumption, ecological environment and human health are still lacking. Based on the research status and the actual situation of Qinghai-Tibet Plateau, this paper strengthens the study of household energy consumption and its impact on eco-environment and human health through macro level and micro level. On the macro level, we need to (1) clarify the correlation and driving mechanism between household energy, grassland ecology and human health and form the theoretical framework for analysis in the pastoral region of Qinghai-Tibet Plateau; (2) build a comprehensive modular assessment method around the energy-ecology-environment-health-economy nexus. On the micro -level, we should (1) carry out the research on the characteristics and dynamics changes of household energy consumption on the Qinghai-Tibet Plateau; (2) establish and quantify the feedback mechanism between household energy consumption and ecosystem; (3) strengthen the measurement of indoor air pollutant concentration in the pastoral areas and complete the data collection on the exposure characteristics and the associated health risks for the residents living in the alpine areas. 参考文献 相似文献 引证文献

Evaluation method and empirical application of construction land suitability and arable land suitability in alpine-gorge region of Qinghai-Tibet Plateau: A case study of Nyingchi city

Evaluation method and empirical application of construction land suitability and arable land suitability in alpine-gorge region of Qinghai-Tibet Plateau: A case study of Nyingchi city

Modernization Measures for Sustainable Development of Alpine Grassland Husbandry on the Qinghai-Tibet Plateau: An Example of Countermeasures to Pasture Degradation

The Qinghai-Tibet Plateau, also known as the "third pole of the world", consists of widespread alpine grasslands, and the local community has taken advantage of this natural condition to develop alpine grassland livestock farming. In recent years, climate change and irrational human activities have led to serious degradation of the alpine grasslands on the Qinghai-Tibet Plateau, which has constrained the development of traditional grassland husbandry. In order to promote the ecological protection of the plateau and improve the livelihood of the people in this region, the traditional grassland livestock industry needs to be transformed and upgraded. The Qinghai-Tibet Plateau should study and reasonably learn from efficient modern pastoralism and development measures such as grass farming and migrant urbanization in the USA, Australia, and Northern Europe. Due to the special peculiarities of the natural environment and the limitations of the local socio-economic conditions, this essay combines the local natural and humanistic environment of the Qinghai-Tibet Plateau region and proposes modern measures such as grass-based storage, grazing in specific areas, and ecological migration to realize the sustainable development of alpine grassland animal husbandry, which is conducive to promote regional high quality development.

Does China’s poverty alleviation policy improve the quality of the ecological environment in poverty-stricken areas?

Poverty eradication and environmental protection as the two global goals of sustainable development. China’s poverty alleviation policy attempts to achieve green development in poverty-stricken areas by eliminating poverty while also promoting environmental protection. Since the Poverty-stricken counties on the Qinghai-Tibet Plateau also have the dual attributes of ecological degradation and ecological fragility, it is of great significance to study the impact of poverty alleviation policy on their environment. In this research, taking poverty alleviation policy as the entry point, based on panel data and Remote Sensing Ecological Index for poverty-stricken counties on the Qinghai-Tibet Plateau from 2011 to 2019, and using the difference-in-differences (DID) method to verify the impact of policy on environmental quality. The main findings of the study were: 1) The poverty alleviation policy has a significant improvement effect on the ecological environment quality of counties in the Qinghai-Tibet Plateau region, and this conclusion still holds in a series of robustness tests using methods including the changing sample size method and the variable replacement method. Moreover, the policy effect has a certain time lag and its effect persists in the long term; 2) It is mainly due to the increased level of government public expenditure and the easing of government financial pressure that has contributed to the improvement of environmental quality in poverty-stricken areas; 3) Policy heterogeneity suggests that industrial poverty eradication policies are more conducive to promoting synergistic economic and environmental development in poverty-stricken areas.

Extensive reorganization of the chloroplast genome of Corydalis platycarpa: A comparative analysis of their organization and evolution with other Corydalis plastomes.

The chloroplast (cp) is an autonomous plant organelle with an individual genome that encodes essential cellular functions. The genome architecture and gene content of the cp is highly conserved in angiosperms. The plastome of Corydalis belongs to the Papaveraceae family, and the genome is comprised of unusual rearrangements and gene content. Thus far, no extensive comparative studies have been carried out to understand the evolution of Corydalis chloroplast genomes. Therefore, the Corydalis platycarpa cp genome was sequenced, and wide-scale comparative studies were conducted using publicly available twenty Corydalis plastomes. Comparative analyses showed that an extensive genome rearrangement and IR expansion occurred, and these events evolved independently in the Corydalis species. By contrast, the plastomes of its closely related subfamily Papaveroideae and other Ranunculales taxa are highly conserved. On the other hand, the synapomorphy characteristics of both accD and the ndh gene loss events happened in the common ancestor of the Corydalis and sub-clade of the Corydalis lineage, respectively. The Corydalis-sub clade species (ndh lost) are distributed predominantly in the Qinghai-Tibetan plateau (QTP) region. The phylogenetic analysis and divergence time estimation were also employed for the Corydalis species. The divergence time of the ndh gene in the Corydalis sub-clade species (44.31 - 15.71 mya) coincides very well with the uplift of the Qinghai-Tibet Plateau in Oligocene and Miocene periods, and maybe during this period, it has probably triggered the radiation of the Corydalis species. To the best of the authors' knowledge, this is the first large-scale comparative study of Corydalis plastomes and their evolution. The present study may provide insights into the plastome architecture and the molecular evolution of Corydalis species.

Root uptake dominates mercury accumulation in permafrost plants of Qinghai-Tibet Plateau

Uptake of atmospheric elemental mercury via foliage is thought to be the dominant pathway of mercury accumulation in terrestrial ecosystems, including those in the Arctic permafrost regions. Whether a similar process operates in alpine permafrost regions remains unknown. Here we report mercury concentrations and stable isotopic signatures in a large cluster alpine permafrost regions of mid-latitude Qinghai-Tibet Plateau. We find a transition from foliage to root uptake of mercury as elevation increases. In alpine permafrost regions, we find that root uptake of mercury from the surrounding soil is the dominant accumulation pathway. We estimate that root uptake accounts for 70 ± 19% of plant mercury in permafrost regions of the Qinghai-Tibet Plateau and propose that this may be related to the harsh climate conditions suppressing foliage growth and promoting lateral root growth.

An Empirical Analysis of the Role of Forage Product Trade on Grassland Quality and Livestock Production in China

The restoration of grassland ecosystems and the development of the livestock industry in China are constrained by a gap in livestock feed supply and demand. The importation of forage products, as an important means to bridge this feed gap, deserves attention for its relationship with grassland quality and livestock production. This paper empirically examines the relationship between forage products trade and grassland quality, as well as livestock production. The paper uses a cointegration test and error correction model based on data on forage product trade, grassland quality, and livestock production in seven livestock-type regions from 2006 to 2020. The results show that forage product trade has a long-term stable equilibrium relationship with grassland quality in China. The relationships between forage product trade and livestock production in different livestock-type regions are heterogeneous. Among these heterogeneous results, livestock production in the Qinghai-Tibet Plateau region, Loess Plateau Region, Southwest Mountain Region, and Northeast Region are closely related to forage product trade. It appears that importation of feed reduces pressure on natural grasslands, as well as providing high-quality feed that improves livestock production. The above findings can help explain the characteristics of livestock production in different livestock-type regions in China, as well as provide empirical evidence and new ideas for restoring grassland environments and developing herbivorous animal husbandry.

Between allopatry and secondary contact: differentiation and hybridization among three sympatric Gentiana species in the Qinghai-Tibet Plateau

BackgroundMountains of the world host a significant portion of all terrestrial biodiversity, and the region of the Qinghai-Tibet Plateau (QTP) stands as one of the most remarkable mountain regions on Earth. Because many explosive radiations occurred there, the QTP is a natural laboratory which is ideal to investigate patterns and processes linked to speciation and diversification. Indeed, understanding how closely related and sympatric species diverged is vital to explore drivers fostering speciation, a topic only rarely investigated in the QTP. By combining genomic and environmental data, we explored the speciation process among three closely related and sympatric species, Gentiana hexaphylla, G. lawrencei and G. veitchiorum in the QTP region.ResultsCombining genome sizes and cytological data, our results showed that G. hexaphylla and G. veitchiorum are diploid, whereas G. lawrencei is tetraploid. Genetic clustering and phylogenetic reconstruction based on genomic SNPs indicated a clear divergence among the three species. Bayesian clustering, migrant, and D-statistic analyses all showed an obvious signature of hybridization among the three species, in particular between G. lawrencei and both G. hexaphylla and G. veitchiorum in almost all populations. Environmental variables related to precipitation and particularly temperature showed significant differences among the three gentians, and in fact a redundancy analysis confirmed that temperature and precipitation were the major climatic factors explaining the genetic differentiation among the three species.ConclusionOur study suggested that ancient hybridization, polyploidization, geological isolation and the evolution of different climatic preferences were all likely to be involved in the divergence of the three Gentiana species, as may be the case for many other taxa in the QTP region.

Salt Tolerant Bacillus Strains Improve Plant Growth Traits and Regulation of Phytohormones in Wheat under Salinity Stress.

Soil salinity is a major constraint adversely affecting agricultural crops including wheat worldwide. The use of plant growth promoting rhizobacteria (PGPR) to alleviate salt stress in crops has attracted the focus of many researchers due to its safe and eco-friendly nature. The current study aimed to study the genetic potential of high halophilic Bacillus strains, isolated from the rhizosphere in the extreme environment of the Qinghai–Tibetan plateau region of China, to reduce salt stress in wheat plants. The genetic analysis of high halophilic strains, NMCN1, LLCG23, and moderate halophilic stain, FZB42, revealed their key genetic features that play an important role in salt stress, osmotic regulation, signal transduction and membrane transport. Consequently, the expression of predicted salt stress-related genes were upregulated in the halophilic strains upon NaCl treatments 10, 16 and 18%, as compared with control. The halophilic strains also induced a stress response in wheat plants through the regulation of lipid peroxidation, abscisic acid and proline in a very efficient manner. Furthermore, NMCN1 and LLCG23 significantly enhanced wheat growth parameters in terms of physiological traits, i.e., fresh weight 31.2% and 29.7%, dry weight 28.6% and 27.3%, shoot length 34.2% and 31.3% and root length 32.4% and 30.2%, respectively, as compared to control plants under high NaCl concentration (200 mmol). The Bacillus strains NMCN1 and LLCG23 efficiently modulated phytohormones, leading to the substantial enhancement of plant tolerance towards salt stress. Therefore, we concluded that NMCN1 and LLCG23 contain a plethora of genetic features enabling them to combat with salt stress, which could be widely used in different bio-formulations to obtain high crop production in saline conditions.