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Forest height inversion with Polarimetric SAR Interferometry (PolInSAR) has become a research hotspot in the field of radar remote sensing. In this paper, we systematically studied a modified two-step, three-stage inversion simulating the L-band (L = 23 cm) full-polarization interferometric SAR data with an average forest height of 18 m using ESA PolSARpro-SIM software. We applied this method to E-SAR L-band single-baseline full PolInSAR data in 2003. In the first step, we modified the three-stage inversion algorithm based on phase diversity (PD)/maximum coherence difference (MCD) coherence optimization methods, corresponding to PD, MCD, respectively. In the second step, we introduced the coherence amplitude inversion term and modified the fixed weight to the variable of ε times the ground scattering ratio, which improved the accuracy of forest height inversion. The mean of forest height inversion by the HV method was the lowest (15.83 m) and the RMSE was the largest (4.80 m). The PD method was superior to the HV method with RMSE (4.60 m). The MCD method was slightly better than using the PD method with the smallest RMSE (4.43 m). After adding the coherence amplitude term, the RMSE was improved by 0.15 m, 0.14 m, and 0.08 m, respectively. The smallest RMSE was obtained by MCD, followed by the PD and HV methods. Although the robustness of the forest height inversion algorithm was reduced, the underestimation was improved and the RMSE was reduced. Due to the complexity of the real SAR E-SAR L-band single-baseline full PolInSAR data and the small sample sizes, the three-stage inversion methods based on coherent optimization were lower than the three-stage in-version method. After introducing the coherent magnitude term, the overestimation of the forest height was significantly weakened in HVWeight, PDweight, and MCDWeight, and PDWeight was optimal. The modified two-step, three-stage inversion algorithm had significant effects in alleviating forest height underestimation and overestimation, improving the accuracy of forest height inversion, and laying a foundation for the upcoming L-band SAR satellite generation, new SAR and LIDAR systems combined with RPAs (remotely piloted aircrafts)/UAVs (unmanned aerial vehicles) for small areas mapping initiatives, and promoting the depth and breadth of the SAR applications of the new SAR system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Combined metabolomics and transcriptomics strategy was established for comparison study. • Cultivated and wild O. sinensis showed notable differences in the expression patterns of metabolites and genes. • Wild O. sinensis exhibited higher levels of nucleotides and nucleosides, while cultivated O. sinensis contained large amounts of amino acids, carbohydrates and phenolic acids. • Differentially expressed genes involved in purine nucleotide metabolism were identified. Ophiocordyceps sinensis is a traditional medicinal fungus endemic to the alpine and high-altitude areas of the Qinghai-Tibet plateau. The scarcity of the wild resource has led to increased attention to artificially cultivated O. sinensis. However, little is known about the metabolic differences and the regulatory mechanisms between cultivated and wild O. sinensis. This study exploited untargeted metabolomics and transcriptomics to uncover the differences in accumulated metabolites and expressed genes between wild and cultivated O. sinensis. Metabolomics results revealed that 368 differentially accumulated metabolites were mainly enriched in biosynthesis of amino acids, biosynthesis of plant secondary metabolites and purine nucleotide metabolism. Cultivated O. sinensis contained more amino acids and derivatives, carbohydrates and derivatives, and phenolic acids than wild O. sinensis , whereas the contents of most nucleosides and nucleotides in wild O. sinensis were significantly higher than in cultivated O. sinensis. Transcriptome analysis indicated that 4430 annotated differentially expressed genes were identified between two types. Integrated metabolomics and transcriptomics analyses suggested that IMPDH , AK , ADSS , guaA and GUK genes might be related to the synthesis of purine nucleotides and nucleosides. Our findings will provide a new insight into the molecular basis of metabolic variations of this medicinal fungus. [ABSTRACT FROM AUTHOR]

Ophicordyceps sinensis is a well-known traditional Chinese medicine and cultured mycelium is a substitute for wild O. sinensis . Metabolic profiles of wild O. sinensis from three geographical locations and cultivated mycelia derived from three origins were investigated using 1 H nuclear magnetic resonance (NMR) analysis combined with multivariate statistical analysis. A total of 56 primary metabolites were identified and quantified from O. sinensis samples. The principle component analysis (PCA) showed significant differences between natural O. sinensis and fermentation mycelia. Seven metabolites responsible for differentiation were screened out by orthogonal partial least squares discriminant analysis (OPLS-DA). The concentrations of mannitol, trehalose, arginine, trans-4-hydroxyproline, alanine and glucitol were significantly different between wild and cultured groups. The variation in metabolic profiling among artificial mycelia was greater than that among wild O. sinensis . Furthermore, wild samples from different origins were clearly distinguished by the levels of mannitol, trehalose and some amino acids. This study indicates that 1 H NMR-based metabolomics is useful for fingerprinting and discriminating O. sinensis of different geographical regions and cultivated mycelia of different strains. The present study provided an efficient approach for investigating chemical compositions and evaluating the quality of medicine and health food derived from O. sinensis . [ABSTRACT FROM AUTHOR]

Insect tea is a traditional health drink produced by the Miao, Dong and Yao ethnic minorities in southwest China. However, little information is available on the chemical differences of various insect teas. The present study aimed to comprehensively compare the chemical profiles of three typical insect teas (Hawk, Sanye and Huaxiang insect teas) using ultra-performance liquid chromatography coupled to Q Exactive hybrid quadrupole-Orbitrap mass spectrometry (UPLC-Q-Exactive-MS) based metabolomics approach and evaluate their antioxidant activities. Totally, 283 metabolites were tentatively identified. Multivariate analyses demonstrated that three types of insect teas significantly varied in metabolite distribution patterns, and 180 compounds were identified as potential biomarkers. Hawk samples were characterized by higher levels of flavonoids, whereas Huaxiang had higher contents of phenolic acids and amino acids. Moreover, Hawk also revealed the highest contents of total phenolics, and possessed the strongest 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) scavenging activity and ferric reducing antioxidant power. The well positive correlations were found between the antioxidant properties with their contents of phenolic compounds. These results indicate that insect teas are rich in phenolic compounds and could be used as promising source of natural antioxidants. • UPLC-Q-Extractive-MS-based metabolomics was applied to insect teas. • Three insect teas were clearly discriminated according to metabolite profiles. • Hawk and Huaxiang insect teas stood out with greater antioxidant activity. • Phenolic compounds contributed to higher antioxidant activity of insect teas. [ABSTRACT FROM AUTHOR]

• Differences in metabolites between natural Ophiocordyceps sinensis and its cultured mycelia were compared. • Multivariate analysis showed a clear discrimination between natural and cultured O. sinensis. • Sixteen differential metabolites were found as the chemical markers responsible for the discrimination. • Natural O. sinensis collected from different geographical regions were completely separated by OPLS-DA. Ophiocordyceps sinensis , one of the well-known traditional Chinese medicine, has multiple health-promoting effects. It is used as herbal remedy and health food in Asian countries, together with its cultured mycelia used as a substitute of natural O. sinensis. In the present study, natural O. sinensis collected from three geographical regions and its cultured mycelia derived from three strains were analyzed by gas chromatography-mass spectrometry (GC–MS) combined with chemometrics. A total of 72 metabolites were identified from all samples with different metabolic profiles observed between natural O. sinensis and cultured mycelia. Among them, 50 metabolites showed significant differences between natural O. sinensis and cultured mycelia. Higher levels of trehalose, glycerol and citric acid in natural O. sinensis were found compared to those in cultured mycelia, while myo -inositol and some amino acids were more abundant in cultured mycelia. In addition, chemical compositions of natural O. sinensis varied depending on the geographical regions. Natural O. sinensis from three locations were clearly differentiated by the concentrations of meso -erythritol, D -mannitol, glucose and organic acids. The current study provides a comprehensive metabolic profiles of natural O. sinensis and its cultured mycelia, which is potentially important for understanding the metabolism of O. sinensis and facilitating the application of cultured mycelia as a supplement of natural O. sinensis. [ABSTRACT FROM AUTHOR]

Global greening and its eco-environmental outcomes are getting mounting international focus. The important contribution of China to the global greening is highly appreciated. However, the basic driving forces are still elusive. The Loess Plateau (LP) and Three-River Source Region (TRSR) were chased as study areas in Northern China. The prior one represents the region experiencing intensive human interventions from ecological engineering projects, while the latter is a typical region that is experiencing faster climate change. Hypothesized to be driven by a disproportionate rate of human activities and climates, also being regions of typical large-scale ecological engineering projects, the study goal is to identify the actual driving forces on vegetation dynamics in these two regions. Trend analysis, correlation analysis, and residual trend-based method (RESTREND) were utilized to understand the relationships between climate variability, human activities, and vegetation dynamics. The spatiotemporal variations of vegetation from 1982 to 2019 were evaluated and the respective impacts of climatic and anthropogenic factors on vegetation dynamics were disentangled. Indicating apparent vegetation restoration in LP and TRSR, the results depict that annual LAI has remarkably increased during the 38 years. Temperature and precipitation promoted vegetation growth, whereas the solar radiation and vapor pressure deficit hampered it. After implementing the ecological engineering projects, the primary climatic factor changed from temperature to precipitation. Meanwhile, human activities act as the major driving factor in vegetation greening in the entire study area, with a contribution rate exceeding 70%. This information highlights that ecological engineering can significantly reduce the risks of ecosystem degradation and effectively restore vegetation, especially in ecologically sensitive and vulnerable areas. [ABSTRACT FROM AUTHOR]

• Vegetation greening slows land surface warming in Chinese drylands. • Biogeophysical feedback of vegetation greening to climate is seasonally asymmetric. • Land use change amplifies the greening-induced cooling effects. Vegetation change can provide strong feedback to climate system, but there is a severe shortage of understanding regarding how biogeophysical (BGP) processes related to vegetation changes and their impact on local temperature in arid and semi-arid regions of China (ASAC), a unique region where large-scale ecological engineering projects have been implemented. To address this knowledge gap, this study is aims to investigate the BGP effects of vegetation changes (including growth change and type conversion) and elucidate the BGP mechanisms that link vegetation and surface temperature (T s) through integrating the Intrinsic Biophysical Mechanism (IBM) method and pairwise comparison analysis. The findings reveal that vegetation change slows down climate warming rate of T s in ASAC, with a cooling magnitude of -0.0096 K/year (Non-radiative forcing: -0.0114 K/year; Radiative forcing: 0.0018 K/year) from 2000 to 2018, embodied as cooling in summer-autumn and warming in winter-spring. Vegetation-induced BGP effects in ASAC are dominated by non-radiative mechanisms. During the study period, compared to the stable land use/land cover (LULC), cropland expansion and grassland restoration usually led to cooling exceeding -0.05 K and -0.01 K, respectively. However, afforestation and urbanization generally cause warming about 0.02 K and 0.04 K, respectively. From a BGP point of view, avoiding large-scale afforestation in extremely arid regions is an effective strategy. This study highlights the importance of land use/ land cover change (LULCC) in regulating regional climates, and emphasizes the necessity of fully considering the multiple effects of LULCC in the formulation or evaluation of climate change mitigation policies. [ABSTRACT FROM AUTHOR]