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Background: Festuca kryloviana is a significant native grass species in the Qinghai Lake region, and its low emergence rate is a primary factor limiting the successful establishment of cultivated grasslands. The region's arid and low-rainfall climate characteristics result in reduced soil moisture content at the surface. Despite the recognized impact of water availability on plant growth, the specific role of moisture in seedling development remains not fully elucidated. This study aims to investigate the germination rate and seedling growth velocity of F. kryloviana seeds under varying moisture conditions, and to integrate physiological and transcriptomic analyses of seedlings under these conditions to reveal the mechanisms by which water influences seedling development. Results: The emergence rate of F. kryloviana seedlings exhibited an initial increase followed by a decrease with increasing moisture content. The highest emergence rate, reaching 75%, was observed under 20% soil moisture conditions. By the eighth day of the experiment, the lengths of the plumules and radicles under the optimal emergence rate (full water, FW) were 21.82% and 10.87% longer, respectively, than those under closely matching the soil moisture content during the background survey (stress water, SW). The differential development of seedlings under varying moisture regimes is attributed to sugar metabolism within the seeds and the accumulation of abscisic acid (ABA). At FW conditions, enhanced sugar metabolism, which generates more energy for seedling development, is facilitated by higher activities of α-amylase, sucrose synthase, and trehalose-6-phosphate synthase compared to SW conditions. This is reflected at the transcriptomic level with upregulated expression of the α-amylase (AMY2) gene and trehalose-6-phosphate synthase (TPS6), while genes associated with ABA signaling and transduction are downregulated. Additionally, under FW conditions, the expression of genes related to the chloroplast thylakoid photosystems, such as photosystem II (PSII) and photosystem I (PSI), is upregulated, enhancing the seedlings' light-capturing ability and photosynthetic efficiency, thereby improving their autotrophic capacity. Furthermore, FW treatment enhances the expression of the non-enzymatic antioxidant system, promoting metabolism within the seeds. In contrast, SW treatment increases the activity of the enzymatic antioxidant system, including peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), to cope with water stress. Conclusions: Our experiment systematically evaluated the impact of moisture conditions on the growth and development of F. kryloviana seedlings. Physiological and transcriptomic data collectively indicate that adequate water (20%) supply enhances seedling growth and development by reducing ABA levels and increasing α-amylase activity within seeds, thereby boosting sugar metabolism and promoting the growth of seedling, which in turn leads to an improved emergence rate. Considering water management in future cultivation practices may be a crucial strategy for enhancing the successful establishment of F. kryloviana in grassland ecosystems. [ABSTRACT FROM AUTHOR]

Changes in the habitats of species can provide insights into the impact of climate change on their habitats. Species in the genus Morina (Morinoideae) are perennial herbaceous plants that are mainly distributed in the South Asian Mountains and Eastern Mediterranean. In China, there are four species and two varieties of this genus distributed across the Yunnan, Sichuan, Qinghai, and Gansu provinces. This study used the optimal MaxEnt model to simulate past, current, and future potentially suitable habitats of Morina kokonorica and Morina chinensis. Seventy data of M. kokonorica occurrences and 3 of M. chinensis were used in the model to predict potentially suitable habitats. The model prediction results indicated that both M. kokonorica and M. chinensis exhibited trends of northward migration to higher latitudes and westward migration along the Himalayas to higher elevations, suggesting that the northern valleys of Hengduan Mountains and northern and eastern parts of the Himalayas were potential refugia for M. kokonorica, and the potential refugia for M. chinensis was located in the eastern part of Qinghai‐Tibet Plateau. The results of this niche analysis showed that the two species had higher levels of interspecific competition and that the environmental adaptability of M. chinensis was stronger. This research could help further understand the response pattern of Morina to environmental change, to understand the adaptability of species to the environment, and promote the protection of species. [ABSTRACT FROM AUTHOR]

In recent years, lakes on the Qinghai–Tibet Plateau have become more responsive to climate change. In September 2011, Zonag Lake in Hoh Xil experienced sudden drainage, the water eventually flowed into Yanhu Lake, which caused Yanhu Lake to continue to expand. The potential collapse of Yanhu Lake could directly threaten the operational safety of the adjacent Qinghai–Tibet Highway, Qinghai–Tibet Railway. To explore the implications of expanding lakes on the surrounding permafrost, we selected Hoh Xil Yanhu Lake on the Qinghai–Tibet Plateau to study the effect of lake expansion on permafrost degradation. The permafrost degradation in the Yanhu Lake basin from October 2017 to December 2022 was inverted using Sentinel–1 satellite image data and small baseline subset interferometry synthetic aperture radar (SBAS–InSAR) technology. Additionally, permafrost degradation from February 2007 and February 2010 was analyzed using advanced land observing satellite phased array–type L–band synthetic aperture radar (ALOS PALSAR) satellite images and differential interferometric synthetic aperture radar (D–InSAR) technique. The results showed that the permafrost around Yanhu Lake experienced accelerated degradation. Prior to the expansion of Yanhu Lake, the average annual deformation rate along the line of sight (LOS) direction was 6.7 mm/yr. After the expansion, the rate increased to 20.9 mm/yr. The integration of spatial-temporal distribution maps of surface subsidence, Wudaoliang borehole geothermal data, meteorological data, Yanhu Lake surface area changes, and water level changes supports the assertion that the intensified permafrost degradation could be attributed to lake expansion rather than the rising air temperature. Furthermore, permafrost degradation around Yanhu Lake could impact vital infrastructure such as the adjacent Qinghai–Tibet Highway and Qinghai–Tibet Railway. [ABSTRACT FROM AUTHOR]

Potassium is the active element of potash fertilizer, its concentration determines the quality of the product. Self-absorption occurs in laser-induced breakdown spectroscopy (LIBS) analysis of potash, since potassium is the major element with a concentration that can reach the level of 95 wt.%. The present work simulated an online analysis of potassium in potash with a laboratory setup, LIBS spectra were recorded on 27 potash samples collected from a factory in Qinghai province in China with different potassium concentrations in the range from 90 to 97 wt.%. The self-absorption correction was applied to the spectra for K I 404.4 nm and K I 693.9 nm lines. Multivariate regression based on machine learning were processed with the self-absorption corrected spectra in order to get a better potassium determination performance compared to that with uncorrected spectra. The results show the effectiveness of self-absorption correction in the improvement of the analytical performance. The obtained multivariate regression model presents a satisfactory performance to fill the requirements of the aimed application of online and real-time analysis of potash on a product transportation belt in a production site with respect to the specific requirements of the related current national standards. [ABSTRACT FROM AUTHOR]

Prevailing lake changes on the Qinghai–Tibetan Plateau (QTP) have occurred. Selin Co, a representative saline lake in the central region of the QTP, has had the largest increase and become the largest endorheic lake in Tibet, but the main cause for its dramatic expansion is still under debate. Based on Landsat images, meteorological data and glacier and permafrost data, the dynamic changes in Selin Co and its surrounding small lakes were systematically discussed, and the driving factors behind these changes were further explored. The results suggest that during 1988–2017, the areas of Bange Co and Cuoe Lake showed slow, overall increasing trends at the rates of 0.28 km2/year and 0.11 km2/year, respectively, and upward trends before 2005 but downward trends afterward. The area of Selin Co substantially increased by 685.8 km2 with a growth rate of 30.39 km2/year, with a slow increase of 27.11 km2 during the period of 1988–1997, a rapid increase of 510.53 km2 during 1997–2005 and an increase of 148.16 km2 during 2005–2017. Accordingly, the lake level and water volume of Bange Co slightly increased by 1.64 m and 0.088 km3, respectively, whereas those of Selin Co significantly rose by 8.138 m and 17.47 km3, respectively. The changes in the areas of Bange Co and Cuoe Lake were mostly related to annual precipitation (AP). The expansion of Selin Co may be partly explained as the discharge from the glacier retreat and permafrost degradation in the watershed. Glacial meltwater has enhanced owing to rising, with a rapid reduction of 165.1 km2 (39%) in the glacier area in the basin between 1980 and 2010. Permafrost degradation has significantly accelerated, with increases in the active layer thickness (ALT) (7.44 cm/year) and soil temperatures at a 15-m depth (0.0346 °C/year). [ABSTRACT FROM AUTHOR]

The availability of suitable native plant species for local animal husbandry development and ecological restoration is limited on the Qinghai-Tibetan Plateau. Therefore, comparisons of the ecological adaptability of native species to alternative habitats and their introduction into new habitats are of high importance. This study is aimed at identifying the alteration in morphological and physiological characteristics by measuring photosynthetic physiology, nutrient content, and growth associated with adaptation of plants to conditions at different altitudes 2450, 2950, 3100, and 3300 m above sea level (a. s. l.) on the plateau. Seeds of the dominant grass, Elymus nutans, were collected from locations at these altitudes and grown at a test location of 2950 m a. s. l. Results indicated that altitude had no significant effect on plant height and root depth. However, the leaf area and total root surface area of plants derived from 2950 and 3300 m a. s. l. showed a parabolic response, being greater than those of plants derived from the lowest (2450 m) and highest (3300 m a. s. l.). Total (root plus shoot) dry matter reduced progressively from 2450 to 3300 m a. s. l, while root : shoot ratio increased progressively with altitude. Seed yield of plants originating from the test altitude (2950 m a. s. l) was significantly higher than at any other altitude, being 20% lower at 2450 m, and 38% and 58% less in populations originating from the higher altitudes (3100 and 3300 m a. s. l.). There was also a parabolic decline in response of Elymus nutans germplasm from 3100, 3300, and 2450 m, compared with plants from 2950 m a. s. l., to photosynthetic rate, total N, soluble sugar, and starch contents. Germplasm from 2450 m a. s. l. had significantly lower shoot and higher root carbon content, lower shoot nitrogen, and lower root carbon-to-nitrogen ratio compared with plants derived from the other three altitudes. It is suggested that the stable, genetically determined morphological and physiological features of ecotypes showed parabolic responses which means these ecotypes have become adapted to local habitats, whereas parameters such as dry matter, total root : shoot ratio, photosynthetic rate, and intercellular CO2 concentration of plants reflected phenotypic linear response to current abiotic conditions. It is postulated that introduced ecotypes from 2450, 3100, and 3300 m could adapt to the environment at 2950 m a. s. l. gradually. We conclude that the increased thermal regime experienced by plants introduced from high altitude to low altitude may facilitate the increased growth of Elymus nutans subtypes. It is important to preserve local strains of native species, or ecotypes, for reintroduction into degraded environments and to maintain the greatest ecosystem stability in the northeastern Tibetan Plateau. [ABSTRACT FROM AUTHOR]

The Qinghai plateau has long grappled with a host of issues, such as grassland overloading and a severe shortage of forage supply, significantly jeopardizing the sustainable development of animal husbandry. Chicory (Cichorium intybus L.) has been regarded as an ideal and sustainable supplemental or alternative feed for livestock. To introduce this high-quality forage grass and enhance pasture resources on the Qinghai Plateau. We explored the adaptability of chicory on the Qinghai Plateau through 2384 chicory distribution records, 8 major environmental variables, and 5 cultivation validation pilots using the Maxent model and actual cultivation planting. The results emphasized that the primary environmental factors affecting the suitable areas for chicory included the precipitation of the driest month, mean temperature of the coldest quarter, annual mean temperature, annual precipitation, minimum temperature of the coldest month, and temperature of the coldest month. The regions with high and medium suitability for chicory cultivation are predominantly situated in the eastern, central, and southern areas of Qinghai. The high suitable area covers 29,479 km2, while the medium suitable area extends over 85,090 km2, and the arable land appropriate for chicory cultivation encompasses approximately 40.45 × 104 hm2, constituting 71.7% of the province's arable land. Moreover, practical chicory cultivation across different arable zones revealed that growth and yield in high arable regions significantly outperformed those in medium arable zones. We developed a multivariate linear regression (MLR) model, which identified annual precipitation (AP), evaporation (E), and sunshine duration (SD) as the key climatic factors influencing chicory yield on the Qinghai plateau. These findings furnish a theoretical foundation for the establishment of high-yield, high-efficiency cultivation systems, digital production management, and the future promotion of chicory cultivation on the Qinghai plateau. • Main environmental variables effecting chicory include temperature and precipitation. • Potential cultivation areas of chicory on the Qinghai plateau have been identified. • The primary climatic factors effecting chicory yield on the Qinghai plateau have been substantiated. [ABSTRACT FROM AUTHOR]

The soil freeze-thaw phenomenon is one of the most distinguishing peculiarities of the land surface processes over the Qinghai-Tibetan Plateau. By utilizing soil temperature/moisture and air temperature data from the GLDAS-NOAH product, 4 observing networks and 10 meteorological stations over the Qinghai-Tibetan Plateau, the spatio-temporal distribution of the start/end date and the duration of soil freezing and their relationships with air temperature and altitude were investigated with the analytical methods of linear regression model, correlation analysis, sliding t -test and Mann-Kendall test. As a result, the spatial distribution of top-layer soil freeze-thaw processes was characterized by a trend of delaying freezing and advancing thawing from the northwest to the southeast throughout the Qinghai-Tibetan Plateau. Moreover, in the period 1948–2019, the begin date of soil freezing was delayed at a rate of 1.2 d/10a (p-lev <0.0001, R2 = 0.40), and the end date of the soil freezing was advanced at a rate of 0.5 d/10a (p-lev = 0.105, R2 = 0.04). The duration of the soil freeze was shortened with a rate of 2.1 d/10a (p-lev <0.0001, R2 = 0.23) in the southern Changtang but 0.4 d/10a (p-lev <0.0001, R2 = 0.47) in Qinghai and the southern Tibet Plateau. Additionally, the start date of the soil freeze is to be delayed by 2.8 days (p-lev <0.0001, R2 = 0.53), and the end date of the soil freeze is to be advanced by 3.6 (p-lev <0.0001, R2 = 0.61) days as the air temperature rises by 1.0 °C. In the high cold climatological zone on the Qinghai-Tibetan Plateau, there is a trend toward earlier start date of soil freezing by 9.9 days (p-lev <0.0001, R2 = 0.36), and later end date of soil freezing by 14.4 days (p-lev <0.0001, R2 = 0.56) as the altitude increases by 1000.0 m. Furthermore, the seasonal variations of soil temperature and moisture were significantly different from typical strong and weak freezing years, which were defined according to the duration of soil freezing period. These results are of great significance for understanding the soil freeze-thaw process and its variation over the Qinghai-Tibetan Plateau. • The soil freeze-thaw process over the Qinghai-Tibetan Plateau is analyzed by utilizing observing and reanalysis data. • Notable variability of the soil freeze-thaw process was observed at spatio-temporal scales. • The soil freeze-thaw process over the Qinghai-Tibetan Plateau is closely related to the air temperature and altitude. • Soil water and heat vary with intensity of freezing over the Qinghai-Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Lakes on the Qinghai–Tibetan Plateau (QTP) have experienced significant changes, especially the prevailing lake expansion since 2000 in the endorheic basin. The influence of permafrost thawing on lake expansion is significant but rarely considered in previous studies. In this study, based on Landsat images and permafrost field data, the spatial-temporal area changes of lakes of more than 5 km2 in the endorheic basin on the QTP during 2000–2017 is examined and the impact of permafrost degradation on lake expansion is discussed. The main results are that permafrost characteristics and its degradation trend have close relationships with lake changes. Lake expansion in the endorheic basin showed a southwest–northeast transition from shrinking to stable to rapidly expanding, which corresponded well with the permafrost distribution from island-discontinuous to seasonally frozen ground to continuous permafrost. A dramatic lake expansion in continuous permafrost showed significant spatial differences; lakes expanded significantly in northern and eastern continuous permafrost with a higher ground ice content but slightly in southern continuous permafrost with a lower ground ice content. This spatial pattern was mainly attributed to the melting of ground ice in shallow permafrost associated with accelerating permafrost degradation. Whereas, some lakes in the southern zones of island-discontinuous permafrost were shrinking, which was mainly because the extended taliks arising from the intensified permafrost degradation have facilitated surface water and suprapermafrost groundwater discharge to subpermafrost groundwater and thereby drained the lakes. Based on observation and simulated data, the melting of ground ice at shallow depths below the permafrost table accounted for 21.2% of the increase in lake volume from 2000 to 2016. [ABSTRACT FROM AUTHOR]