Alpine grassland restoration, a critical strategy for enhancing soil organic carbon (SOC) sequestration in high-altitude ecosystems, profoundly influences plant-soil-microbe interactions that govern the magnitude of carbon (C)-climate feedback. However, the mechanisms driving plant and microbial regulation of SOC mineralization (i.e., soil CO2-C release) during degraded alpine grassland restoration remain unresolved, limiting predictions of SOC cycling in these vulnerable ecosystems. Here, by integrating passive and active restoration experiments with aerobic incubation, high-throughput sequencing, and biomarker analyses, we disentangled how restoration-induced shifts in SOC composition (plant- and microbial-derived C) and microbial activity and diversity regulate soil CO2-C release in degraded alpine grassland on the Qinghai-Tibetan Plateau. Our results showed that soil CO2-C release increased significantly with restoration progression under both passive and active approaches. Alpine grassland restoration markedly enhanced plant-derived C accumulation and its SOC contribution, while microbial-derived C remained unchanged due to reduced necromass accumulation coefficients. Notably, although active restoration accelerated plant-derived C accumulation, its oxidation decomposition degree was lower compared to passive restoration and even to unrestored heavily degraded grasslands, increasing SOC pool lability. Fungal community restructuring, particularly in the saprophytic fungal community, emerged as a hallmark of restoration. More importantly, we found that elevated soil CO2-C release during degraded alpine grassland restoration was not primarily mediated by microbial activity and diversity shifts but was strongly linked to divergent plant- and microbial-derived C accumulation patterns, especially the dynamics of plant-derived C. These insights underscore the critical roles of plant- and microbial-derived C redistribution in grassland restoration and suggest new mechanisms for restoration-induced soil C dynamics.

Biological soil crusts (BSCs) play key roles in arid, semi-arid regions and ecological marginal habitats. This study focused on four types of sand-fixing plantations established in 1990 in alpine sandy land (Salix psammophila, SL; Caragana korshinskii, NT; Salix cheilophila, WL; Populus simonii, XYY). Soil samples were collected from bare sand, algae crusts, and moss crusts. Soil particle size distribution, physicochemical properties, and enzyme activity were determined. Then bacterial communities were analyzed using high-throughput (Illumina) sequencing and the correlations among these three factors were examined. The results showed that: (1) From bare sand to algae and moss crusts, the content of fine particles (clay + silt) gradually increased. (2) Soil water content (SWC), nutrients and enzyme activities increased progressively. (3) In the study area, the dominant bacterial phyla of BSCs included Pseudomonadota, Cyanobacteria, Actinobacteriota and Vibrionota. Principal Coordinates Analysis (PCoA) and Analysis of Similarities (ANOSIM) results showed that BSCs drive the differentiation of bacterial communities during succession, while forest stands influence their spatial distribution. (4) Spearman’s correlation and redundancy analysis (RDA) showed that available phosphorus (AP), alkaline hydrolyzable nitrogen (AN), soil organic matter (SOM), catalase (CAT), pH, soil water content (SWC), and alkaline phosphatase (ALP) are key physicochemical factors shaping the bacterial community structure of BSCs. Mantel’s test confirmed that these variables mediated BSCs’ bacterial community structure. This study elucidates the mechanisms underlying ecological restoration via BSCs and provides a theoretical basis for future restoration efforts in alpine sandy land.

Epichloë endophytes enhance tolerance to metal stress in various cool-season grasses, but the mechanism of Epichloë-associated grasses responding to different concentrations of Na2SeO3 are still unclear. After Festuca sinensis infected with (EI) or without (EF) Epichloë sinensis were grown for 90 days, the physiochemical and transcriptional profiling of glutathione metabolism in both shoots and roots over a period of 3 days was investigated in pot trials supplied with 0, 20, and 50 mg/L Na2SeO3 using high-throughput RNA sequencing technology. Results of the study showed that Epichloë endophytes increased the glutathione reductase (GR) levels in shoots and roots and reduced the glutathione (GSH) and GSH/GSSG ratio in shoots. Treatment with 20 mg/L Na2SeO3 resulted in elevated levels of GR and GSSG in both shoots and roots of EI and EF plants. In line with the accumulation of GSH in plant tissues, the endophyte enhanced the expression of GCLC (glutamate-cysteine ligase catalytic subunit), GR, APX (ascorbate peroxidase), and 5-OPase (5-oxoprolinase) in shoots in response to 20 mg/L Se, and Grx (glutaredoxin) on day 2 in the presence of Se, while reducing most GST (glutathione S-transferase) genes. Under selenium treatment, the expression of most GST and GR genes was upregulated in shoots of both EI and EF plants, with a higher accumulation of GST genes observed in roots. Our findings suggest that the Epichloë endophyte differentially activated plant glutathione metabolism depending on treatment duration under Se application and could represent a promising strategy for enhancing Se tolerance in F. sinensis.

Active restoration is predominant to reverse grassland degradation and soil organic carbon (SOC) loss. However, early studies focused on the bulk soil carbon (C) dynamics upon grassland degradation and restoration, with limited evidence involving SOC fractions. Here, we explored how the particulate and mineral‐associated OC (POC and MAOC), metal‐bound OC, soil aggregate‐associated OC, SOC molecular structure and microbial‐derived OC respond to grassland degradation and restoration on the Tibetan Plateau, and also studied the effects of active restoration on SOC fractions across grassland ecosystems through a global‐scale meta‐analysis. We found that POC and soil aggregate‐associated OC contents substantially decreased, while MAOC content remained stable after grassland degradation. In contrast, short‐term active restoration induced a significant decrease in MAOC and metal‐bound OC due to lower soil pH, but POC content remained stable, indicating that grassland restoration resulted in a decrease in SOC stability. Moreover, soil aggregate structure and its stability recovered rapidly during short‐term active restoration, but aggregate‐associated OC did not recover or even declined, suggesting asynchrony between them. Nuclear magnetic resonance spectroscopy revealed no significant changes in the SOC molecular composition between intact, degraded and restored grasslands, suggesting that molecular structure alone does not mirror SOC stability. Furthermore, the meta‐analysis revealed that the response of bulk SOC, MAOC and POC in degraded grassland to active restoration occurred sequentially in three phases characterized by vulnerability, retention and re‐loss of SOC, respectively. Synthesis and applications . Combining a field experiment with a global synthesis, we found that grassland restoration induces divergent shifts in SOC fractions, with threshold effects during the grassland restoration chronosequence. Relying solely on overall changes in bulk SOC may misrepresent the true impact of grassland restoration on SOC retention. Therefore, it is essential to pay more attention to the response of the functionally distinct SOC fractions to grassland restoration, which could help us more accurately assess and predict the grassland soil C–climate feedback.

ABSTRACT The biodiversity of CO 2 -assimilating bacterial communities is pivotal for carbon sequestration in agricultural systems. Changes in the diversity, structure, and activity of the soil chemolithoautotrophic bacteria were examined in four agricultural areas, Dulan (DL), Gonghe (GH), Huzhu (HZ), and Datong (DT) counties in Qinghai Province, where wheat, oilseed rape, and barley were planted. This process was performed using Illumina amplicon sequencing of the ribulose-1,5-bisphosphatecarboxylase/oxygenase (RubisCO) gene ( cbbL Form I) and activity data. The diversity, community, and activity of soil autotrophic CO 2 -fixing bacteria differed significantly across soil sites, whereas cbbL -bearing bacterial diversity and activity were similar across different crop types. RubisCO activity in the HZ region was significantly greater than in the other three regions ( P < 0.001). The overall relative abundance trend of the bacterial taxa was similar among the three crop samples. Moreover, 31, 27, 10, and 8 significant linear discriminant analysis effect sizes were identified in the four regions collected from HZ, DL, DT, and GH, respectively. No significant biomarkers were detected in any of the crop groups. Some soil properties had significant relationships with the autotrophic bacterial community composition. IMPORTANCE Agricultural soil plays important roles in carbon fixation during carbon capture and storage. Autotrophic bacteria that utilize inorganic compounds as electron donors for growth fix CO 2 photosynthetically or chemo-autotrophically in diverse ecosystems and affect soil organic carbon sequestration. Soil properties, agronomic management measures, and environmental factors can influence the community composition, abundance, and activity of CO 2 -assimilating bacteria. This study aims at evaluating the effects of different regions and crop types on the abundance, composition, and activity of CO 2 -fixing bacteria in agricultural soil.

Hairgrass (Deschampsia caespitosa), a widely distributed grass species considered promising in the ecological restoration of degraded grassland in the Qinghai-Xizang Plateau, is likely to be subjected to frequent drought and waterlogging stress due to ongoing climate change, further aggravating the degradation of grassland in this region. However, whether it would acclimate to water stresses resulting from extreme climates remains unknown. Proline accumulation is a crucial metabolic response of plants to challenging environmental conditions. This study aims to investigate the changes in proline accumulation and key enzymes in hairgrass shoot and root tissues in response to distinct climate extremes including moderate drought, moderate waterlogging, and dry–wet variations over 28 days using a completely randomized block design. The proline accumulation, contribution of the glutamate and ornithine pathways, and key enzyme activities related to proline metabolism in shoot and root tissues were examined. The results showed that water stress led to proline accumulation in both shoot and root tissues of hairgrass, highlighting the importance of this osmoprotectant in mitigating the effects of environmental challenges. The differential accumulation of proline in shoots compared to roots suggests a strategic allocation of resources by the plant to cope with osmotic stress. Enzymatic activities related to proline metabolism, such as Δ1-pyrroline-5-carboxylate synthetase, ornithine aminotransferase, Δ1-pyrroline-5-carboxylate reductase, Δ1-pyrroline-5-carboxylate dehydrogenase, and proline dehydrogenase, further emphasize the dynamic regulation of proline levels in hairgrass under water stress conditions. These findings support the potential for enhancing the stress resistance of hairgrass through the genetic manipulation of proline biosynthesis and catabolism pathways.

Selenium (Se) has garnered increasing attention in the field of nutrition, as it is essential for both humans and animals. Certain microorganisms can enrich inorganic selenium and convert it into organic selenium. The growth and metabolomic profiles of six lactobacilli strains exposed to 50 μg/mL of sodium selenite were performed using gas chromatography tandem time-off light mass spectrometry (GC-TOF-MS) analysis. The addition of selenium significantly increased both the population and weight of the Lacticaseibacillus rhamnosus PS5, Lbs. rhamnosus RT-B, Limosilactobacillus reuteri 3630, and Lmb. reuteri 1663 strains, while those of the other two strains decreased. A total of 271 metabolites were determined, with their concentrations ranked from highest to lowest as follows: organic acids and derivatives, oxygen compounds, lipids and lipid-like molecules, and benzenoids. In certain groups, the concentrations of serine, aspartic acid, trehalose, palmitic acid, methylthreonine, and melibiose increased significantly, whereas glucuronic acid, ribose, ornithine, and methionine were downregulated. The metabolic pathways were significantly associated with ABC transporters, glycine, serine, threonine metabolism, and aminobenzoate degradation and other pathways. Based on these findings, we concluded that the transport, absorption, assimilation, and stress response to selenium by lactobacilli in metabolomic changed. Furthermore, the metabolomic alterations among different types of lactobacilli varied primarily due to their distinct properties.

Objective:Based on transcriptome sequencing analysis,the effect of grape seed procyanidins on HepG2 cell genes and related functions was identified.The key genes and metabolic pathways involved in the treatment of HepG2 cells with procyanidins were confirmed.Methods:Through transcriptome sequencing,screening differential genes,gene functional annotation and enrichment analysis of the KEGG pathway,transcriptome studies were conducted on grape proanthocyanidin-treated cells.Results:After treating HepG2 cells with grape anthocyanins,the main biological processes enriched are cellular processes,metabolic processes,biological regulatory processes,immune system processes,reproductive regulation,and growth regulation.Research has found that 12 key differentially expressed genes in cell apoptosis are associated with TNF,p53,MAPK,PI3K-Akt and NF-κB signaling pathway is closely related.Conclusion:Cell apoptosis is closely related to the TNF signaling pathway,p53 signaling pathway,PI3K/Akt signaling pathway,NF-κB signaling pathway and MAPK signaling pathway.

Fungal endophytes exhibit symbiotic relationships with their host plants and convert inorganic selenium to organoselenium and Se0. In order to elucidate how Epichloë sinensis from Festuca sinensis adapts to different concentrations of sodium selenate, the dynamic changes of mycelial enzyme activities and metabolic changes at the transcriptional level were documented over a period of 36 h. The activity of enzymes (superoxide dismutase, glutathione reductase, glutathione S-transferase, cysteine synthetase, and methionine synthesis) in mycelia increased in the presence of increased Se concentrations during the cultivation period. The strain with selenium enrichment showed differential changes in gene expression compared to the strain without selenium enrichment, with more changes observed at higher Se concentrations over time. Notably, genes related to ribosomes or ribosome biogenesis in eukaryotes showed significant expression differences among certain groups, with up-regulation of genes involved in oxidoreductase activity, superoxide dismutase, and siderophore biosynthetic processes, and down-regulation of genes involved in steroid biosynthesis. These findings contribute to a better understanding of the transcriptional response of Epichloë sinensis to selenium.

Global climate warming and shifts in rainfall patterns are expected to trigger increases in the frequency and magnitude of drought and/or waterlogging stress in plants. To cope with water stress, plants develop diverse tactics. However, the adoption capability and mechanism vary depending upon the plant species identity as well as stress duration and intensity. The objectives of this study were to evaluate the species-dependent responses of alpine herbaceous species to water stress. Nine herbaceous species were subjected to different water stresses (including moderate drought and moderate waterlogging) in pot culture using a randomized complete block design with three replications for each treatment. We hypothesized that water stress would negatively impact plant growth and metabolism. We found considerable interspecies differences in morphological, physiological, and biochemical responses when plants were exposed to the same water regime. In addition, we observed pronounced interactive effects of water regime and plant species identity on plant height, root length, root/shoot ratio, biomass, and contents of chlorophyll a, chlorophyll b, chlorophyll (a+b), carotenoids, malondialdehyde, soluble sugar, betaine, soluble protein and proline, implying that plants respond to water regime differently. Our findings may cast new light on the ecological restoration of grasslands and wetlands in the Qinghai-Tibetan Plateau by helping to select stress-tolerant plant species.

以发草（Deschampsia caespitosa）为供试材料，通过盆栽模拟水分胁迫，研究重度干旱、中度干旱、轻度干旱、植物正常需水量（对照）、轻度水涝、中度水涝、重度水涝处理下发草叶片脯氨酸（Pro）积累状况及其代谢途径中底物、中间产物和关键酶的动态变化，以期从脯氨酸代谢途径对发草抗旱/涝机理进行初步探讨。结果显示，干旱和水涝胁迫前期发草叶片Pro含量显著升高，谷氨酸（Glu）和鸟氨酸（Orn）含量显著下降，Δ~1-吡咯琳-5-羧酸合成酶（P5CS）活性、鸟氨酸转氨酶（δ-OAT）活性、Δ~1-吡咯琳-5-羧酸还原酶（P5CR）活性均显著增强，而脯氨酸脱氢酶（ProDH）活性显著降低，表明干旱和水涝胁迫前期发草叶片通过脯氨酸合成代谢的加强和分解代谢的抑制共同积累脯氨酸，以缓解干旱和水涝胁迫产生的危害，Glu途径和Orn途径协同作用于叶片脯氨酸合成代谢过程。中度、轻度干旱和轻度水涝处理21 d后Pro含量趋于稳定，持续21 d的重度干旱处理和持续28 d的重度水涝处理时发草死亡，共同显示了发草对水涝和干旱具有较强的耐受性。结论为高寒沼泽湿地旱涝“共耐性”植物的研究提供理论基础，同时为利用发草开展退化高寒沼泽湿地植被恢复提供科学依据。

Abstract Selenium (Se) is a member of trace elements which are critical for proper functioning of an organism, and is one of the abiotic stressors which affect living organisms growth and metabolite. In this study, Epichloë sp. from Festuca sinensis was submitted to increasing Na 2 SeO 3 concentrations (0, 0.1, and 0.2 mmol/L) in the liquid media for 8 weeks. Epichloë sp. mycelia and fermentation broth were collected by centrifuging at 4, 5, 6, 7, 8 weeks of cultivation, respectively. About 157 and 198 metabolites were respectively determined in fermentation broth and mycelia using gas chromatography-mass spectrometer (GC-MS) analysis. Diverse changes in extracellular and intracellular metabolites were observed as Epichloë sp. exposured to selenite conditions and cultivation time. Eight common contributed metabolites (alanine, valine, isoleucine, glycine, serine, aminomalonic acid, 4-aminobutyric acid, and phenylalanine) were determined in fermentation broth and mycelia using principal component analysis (PCA). Some metabolites had highly accumulated in fermentation broth while others decreased after different time of exposure to Se as compared to the control media. However some metabolites were presented at lower concentrations in mycelia cultivated at selenite concentrations. These metabolites changed were involved in amino acids, carbohydrates, organic acids, fatty acids, and nucleotides under Se conditions, as well as ones over time. Based on these results, we conclude that selenite concentrations and culture time influenced the extracellular and intracellular metabolite profiles of Epichloë sp. from F. sinensis .

设置不同亚硒酸钠浓度(0、0.1、0.2、0.3、0.4 mmol·L-1)和不同培养时间(4、5、6、7、8周)试验因素,研究其对中华羊茅内生真菌Epichlo? sp.液体培养发酵液中pH、氨态氮、还原糖、总糖、可溶性蛋白质、蛋白酶、硒含量的影响.结果表明:硒浓度、培养时间以及硒浓度与培养时间互作对内生真菌发酵液各指标的影响达极显著水平.随着培养时间的延长,发酵液中pH、可溶性蛋白质呈先下降后上升趋势,总糖则呈先升后降再升趋势,硒含量呈先降后升再降动态变化.对照组培养7周时发酵液氨态氮和可溶性蛋白质含量最多,培养8周时发酵液中蛋白酶和还原糖含量分别在0.3、0.4 mmol·L-1亚硒酸钠浓度下达到最大值,培养5周时添加硒浓度为0.3、0.4 mmol·L-1的发酵液中总糖含量最多,在0.4 mmol·L-1硒浓度下发酵液硒含量于培养4周时达到最高值.

Plant growth and development are closely related to water availability. Water deficit and water excess are detrimental to plants, causing a series of damage to plant morphology, physiological and biochemical processes. In the long evolutionary process, plants have evolved an array of complex mechanisms to combat against stressful conditions. In the present study, the duration-dependent changes in ascorbate (AsA) and glutathione (GSH) contents and activities of enzymes involved in the AsA-GSH cycle in hairgrass (Deschampsia caespitosa) in response to water stress was investigated in a pot trial using a complete random block design. The treatments were as follows: (1) heavily waterlogging, (2) moderate waterlogging, (3) light waterlogging, (4) light drought, (5) moderate drought, (6) heavily drought, and (7) a control (CK) with plant be maintained at optimum water availability. The hairgrass plants were subjected to waterlogging or drought for 7, 14, 21 and 28 days and data were measured following treatment. Results revealed that hairgrass subjected to water stress can stimulate enzymatic activities of ascorbate peroxidase (APX), glutathione peroxidase (GPX), glutathione reductase (GR), dehydroascorbate reductase (DHAR), monodehydroascorbate reductase (MDHAR) and L-galactono-1, 4-lactone dehydrogenase (GalLDH), switched on the ascorbate-glutathione (AsA-GSH) cycle and the L-galactose synthesis, up-regulated the contents of AsA and GSH, and maintained higher ratios of ascorbate to dehydroascorbate (AsA/DHA) and reduced glutathione to oxidized glutathione (GSH/GSSG) to alleviate potential oxidative damage. However, the light waterlogging did not induce hairgrass under stress to switch on the AsA-GSH pathway. In general, the critic substances and enzyme activities in AsA-GSH metabolic pathway increased as the increase of water stress intensity. As the increase of exposure duration, the critic antioxidant substances content and enzyme activities increased first and then maintained a relatively stable higher level. Our findings provide comprehensive information on biochemical responses of hairgrass to hydrological change, which would be a major step for accelerating ecological restoration of degradation alpine marshes in the Qinghai-Tibetan Plateau.

>Every year,millions of people travel to high-elevation regions(≥2500 m above sea level) for sightseeing,mountaineering,trekking,skiing or commercial and scientific research activities.As the largest and highest plateau of the world,the Qinghai-Tibet Plateau (QTP) is one of the most attractive tourist destinations because of its multiple splendid sceneries.High-altitude illnesses occur when the rate of ascent to a high altitude overcomes the ability of the individual to acclimatize.Chronic mountain sickness(CMS) is one of the most important high-altitude pathologies in most high-altitude regions over the world.Its hallmark sign is excessive erythrocytosis.In more advanced and severe stages,

Incarvillea compacta Maxim is a traditional Tibetan medicine used to treat inflammation-related diseases, such as pneumonia, fever, jaundice, and otitis media. However, no studies have examined its anti-inflammatory mechanism. To validate the anti-inflammatory activity of I. compacta extract (ICE) and its protective effect on acute alcoholic gastritis, Phytochemicals of I. compacta were identified using Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Lipopolysaccharide (LPS)-induced RAW 264.7 macrophages were used in vitro along with an in vivo a mouse acute gastritis model. Pro-inflammatory mediators and cytokines were measured using the Griess reagent and Cytometric bead array (CBA) assay. Furthermore, inflammation-related molecules were analysed by Western blotting, RNA-Seq, and real-time quantitative PCR (RT-qPCR). The experimental results revealed that ICE decreased the nitric oxide (NO), IL-6, MCP-1, and TNF-α levels in LPS-stimulated RAW 264.7 cells, and downregulated the expression and phosphorylation of PDK1, AKT, and GSK3β. Moreover, ICE also downregulated the activation of NLRP3. The RNA-Seq analysis revealed that 340 differentially expressed genes (DEGs) response to ICE treatment was enriched in several inflammation-related biological processes. The results of the in vivo mouse acute gastritis model showed that ICE significantly reduced inflammatory lesions in the gastric mucosa and remarkably downregulated the expression of iNOS, TNF-α, IL-1β, and IL-6 mRNA in gastric tissue. Therefore, the results of this study obtained scientific evidence supporting the use of I. compacta.

Selenium (Se) is not only an essential trace element critical for the proper functioning of an organism, but it is also an abiotic stressor that affects an organism’s growth and metabolite profile. In this study, Epichloë sp. from Festuca sinensis was exposed to increasing concentrations of Na2SeO3 (0, 0.1, and 0.2 mmol/L) in a liquid media for eight weeks. The mycelia and fermentation broth of Epichloë sp. were collected from four to eight weeks of cultivation. The mycelial biomass decreased in response to increased Se concentrations, and biomass accumulation peaked at week five. Using gas chromatography-mass spectrometry (GC-MS), approximately 157 and 197 metabolites were determined in the fermentation broth and mycelia, respectively. Diverse changes in extracellular and intracellular metabolites were observed in Epichloë sp. throughout the cultivation period in Se conditions. Some metabolites accumulated in the fermentation broth, while others decreased after different times of Se exposure compared to the control media. However, some metabolites were present at lower concentrations in the mycelia when cultivated with Se. The changes in metabolites under Se conditions were dynamic over the experimental period and were involved in amino acids, carbohydrates, organic acids, fatty acids, and nucleotides. Based on these results, we conclude that selenite concentrations and culture time influence the growth, extracellular and intracellular metabolite profiles of Epichloë sp. from F. sinensis.

为测定亚硒酸钠浓度和培养时间对中华羊茅内生真菌液体培养菌丝体干物质和矿质元素的影响,菌丝体样品经微波消化后,采用钼蓝比色法、四苯硼钠法、偶氮氯膦III法、邻菲啰啉比色法、氢化物原子荧光光谱法分别测定磷、钾、钙、铁、硒的含量.结果表明,当培养时间为4周、5周、6周、7周或8周时,亚硒酸钠浓度0.1～0.4 mmol/L抑制内生真菌菌丝体生长,5～6周时菌丝体干物质达到最大值;加亚硒酸钠组菌丝体磷、钾、铁、硒含量显著高于对照组(P<0.05);当培养4周时,添加亚硒酸钠浓度0.3、0.4 mmol/L液体培养菌丝体钙含量明显高于其他处理组(P<0.05).在亚硒酸钠浓度为0.1、0.2、0.4 mmol/L条件下,随着培养时间的延长菌丝体磷、钾、钙、铁含量变化呈现先升后降,均于第6周达到最大值,其含量显著高于其他培养时间(P<0.05).在0.3 mmol/L亚硒酸钠浓度条件下,菌丝体磷、钾、钙、硒变化趋势为先升后降,分别于培养时间7、5、7、7周达到最大值;菌丝体铁含量随着培养时间延长而下降.当培养4～8周时,对照组菌丝体钙、硒含量呈现先升后降变化,铁含量变化不明显,磷、钾含量分别下降和上升.结果表明,亚硒酸钠能提高中华羊茅内生真菌菌丝体吸收矿质元素的能力.

重金属污染土壤的修复治理工作迫在眉睫.为研究适合在青藏高原种植的Cd污染土壤修复植物,以11个青稞品种为试验材料,研究不同浓度Cd(0,5,10,20,40,80,160和320 rag/L)胁迫对青稞种子萌发情况及幼苗生长的影响.结果 显示,(1)重金属Cd对青稞种子萌发表现出低浓度[p(CdCl2)=20 rag/L]促进和高浓度(p (CdCl2)≥80 mg/L)抑制效应;Cd胁迫对青稞幼苗生长过程的抑制效应强于种子萌发过程.(2) 11个品种青稞种子耐Cd胁迫能力加权隶属函数D值依次为'昆仑14号'＞'昆仑10号'＞'黑青稞'＞'柴青1号'＞'门农1号'＞'门源亮兰'＞'昆仑15号'＞'北青3号'＞'昆仑12号'＞'肚里黄'＞'北青6号'.结果 表明:'昆仑14号'及'昆仑10号'对重金属Cd的耐受性最强,能较好地适应重金属土壤环境,具有作为青藏高原地区Cd污染土壤修复植物的潜力.

本研究以发草为研究对象,通过盆栽模拟水分胁迫,研究干旱、水涝胁迫下发草地上部分及根系中脯氨酸(Pro)积累状况及其代谢途径中底物、中间产物和关键酶的变化.结果显示:1)干旱胁迫和水涝胁迫均使发草Pro含量显著升高(P<0.05),相同的水分处理下发草地上部分及根系中Pro含量相差不大.2)干旱胁迫和水涝胁迫下,发草地上部分和根系中谷氨酸(Glu)含量均显著下降(P<0.05),相同的水分处理下根系中Glu含量大于地上部分.水分胁迫使发草地上部分的鸟氨酸(Orn)含量显著下降(P<0.05),而根系中Orn含量没有显著变化.同时,干旱胁迫和水涝胁迫下,发草地上部分和根系中Δ1-吡咯琳-5-羧酸合成酶、鸟氨酸转氨酶(δ-OAT)、Δ1-吡咯琳-5-羧酸还原酶的活性均显著增强(P<0.05),且地上部分δ-OAT活性强于根系.另外,Δ1-吡咯琳-5-羧酸脱氢酶和脯氨酸脱氢酶活性显著降低(P<0.05).研究结果表明发草通过积累Pro缓解干旱和水涝胁迫,地上部分Pro的积累是Glu途径和Orn途径协同作用的结果,但根系中Pro的积累以Glu途径为主.