NIP1;2 is a plasma membrane-localized transporter mediating aluminum uptake, translocation, and tolerance in Arabidopsis.

Members of the aquaporin (AQP) family have been suggested to transport aluminum (Al) in plants; however, the Al form transported by AQPs and the roles of AQPs in Al tolerance remain elusive. Here we report that NIP1;2, a plasma membrane-localized member of the Arabidopsis nodulin 26-like intrinsic protein (NIP) subfamily of the AQP family, facilitates Al-malate transport from the root cell wall into the root symplasm, with subsequent Al xylem loading and root-to-shoot translocation, which are critical steps in an internal Al tolerance mechanism in Arabidopsis We found that NIP1;2 transcripts are expressed mainly in the root tips, and that this expression is enhanced by Al but not by other metal stresses. Mutations in NIP1;2 lead to hyperaccumulation of toxic Al3+ in the root cell wall, inhibition of root-to-shoot Al translocation, and a significant reduction in Al tolerance. NIP1;2 facilitates the transport of Al-malate, but not Al3+ ions, in both yeast and Arabidopsis We demonstrate that the formation of the Al-malate complex in the root tip apoplast is a prerequisite for NIP1;2-mediated Al removal from the root cell wall, and that this requires a functional root malate exudation system mediated by the Al-activated malate transporter, ALMT1. Taken together, these findings reveal a critical linkage between the previously identified Al exclusion mechanism based on root malate release and an internal Al tolerance mechanism identified here through the coordinated function of NIP1;2 and ALMT1, which is required for Al removal from the root cell wall, root-to-shoot Al translocation, and overall Al tolerance in Arabidopsis.

UV-B Radiation Effects on the Alpine Plant Kobresia humilis in a Qinghai-Tibet Alpine Meadow.

Enhanced UV-B radiation resulting from stratospheric ozone depletion has been documented both globally and on the Qinghai-Tibet Plateau in China. The response of Kobresia humilis, an important alpine meadow plant species, to enhanced UV-B radiation was experimentally investigated at the Haibei Alpine Meadow Ecosystem Research Station (37°29'−37°45' N, 101°12'−101°23' E; alt. 3200 m). K. humilis was exposed to UV-B radiation including ambient UV-B and enhanced UV-B (simulating a 14% reduction in the ozone layer) in a randomized design with three replications of each treatment. Enhanced UV-B radiation resulted in a significant increase of both leaf area and fresh weight chlorophyll and carotenoid but had no effect on UV-B absorbing pigments. Similarly, enhanced UV-B radiation did not significantly change the photosynthetic O2 elevation rate while leaf thickness, width, and length significantly increased (p < 0.01). The enhanced UV-B radiation was associated with 2−3 days earlier flowering and a larger number of flowers per spikelet. The enhanced UV-B generally resulted in larger leaves and more flowers but earlier phenology. In summary, these findings suggest that alpine species of K. humilis have adapted to the strong solar UV-B radiation intensity presented on the Qinghai-Tibet Plateau, but the interspecies differences and their influence on trophic level should be more concerning.

Characterization of the Evolutionary Pressure on Anisodus tanguticus Maxim. with Complete Chloroplast Genome Sequence.

Anisodus tanguticus Maxim. (Solanaceae), a traditional endangered Tibetan herb, is endemic to the Qinghai-Tibet Plateau. Here, we report the de novo assembled chloroplast (cp) genome sequences of A. tanguticus (155,765 bp). The cp contains a pair of inverted repeated (IRa and IRb) regions of 25,881 bp that are separated by a large single copy (LSC) region (86,516 bp) and a small single copy SSC (17,487 bp) region. A total of 132 functional genes were annotated in the cp genome, including 87 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. Moreover, 199 simple sequence repeats (SSR) and 65 repeat structures were detected. Comparative plastome analyses revealed a conserved gene order and high similarity of protein-coding sequences. The A. tanguticus cp genome exhibits contraction and expansion, which differs from Przewalskia tangutica and other related Solanaceae species. We identified 30 highly polymorphic regions, mostly belonging to intergenic spacer regions (IGS), which may be suitable for the development of robust and cost-effective markers for inferring the phylogeny of the genus Anisodus and family Solanaceae. Analysis of the Ka/Ks ratios of the Hyoscyameae tribe revealed significant positive selection exerted on the cemA, rpoC2, and clpP genes, which suggests that protein metabolism may be an important strategy for A. tanguticus and other species in Hyoscyameae in adapting to the adverse environment on the Qinghai-Tibetan Plateau. Phylogenetic analysis revealed that A. tanguticus clustered closer with Hyoscyamus niger than P. tangutica. Our results provide reliable genetic information for future exploration of the taxonomy and phylogenetic evolution of the Hyoscyameae tribe and related species.

Characterization of the complete chloroplast genome of traditional Chinese herb, Solanum japonense Nakai. (Solanaceae).

Solanum japonense Nakai. (Solanaceae) is a traditional Chinese medicine and animal fodder in Asian continent. Here, the complete chloroplast genome sequence of S. japonense was determined by the Illumina Hiseq technology. The complete chloroplast genome of S. japonense was 155,415 bp and the GC content was 37.81%. The typical circular quadripartite structure was composed with two inverted repeat (IR) regions with 25,588 bp, a large single-copy (LSC) region (85,931 bp) and a small single-copy (SSC) region (18,344 bp). The chloroplast genome of S. japonense contained 132 unigenes, which contained 86 protein-coding genes, 37 tRNA and 8 rRNA genes and one pseudo-gene. Moreover, 183 SSRs were identified and 65% (119)of them located at LSC region. A Maximum-Likelihood (ML) phylogenetic analysis based on chloroplast genomes indicated that S. japonense was closely related to S.dulcamara, S.nigrum. Our results would provide a valuable resource for resource utilization and the phylogenetic studies of species of Dulcamara sect. in Solanaceae.

Quantitative analysis of the profiles of twelve major compounds in Gentiana straminea Maxim. Roots by LC-MS/MS in an extensive germplasm survey in the Qinghai-Tibetan plateau.

ETHNOBOTANICAL RELEVANCE: Gentiana straminea Maxim. is a well-known Tibetan traditional herb, which has been used to treat rheumatic arthritis, iceteric hepatitis, and other diseases for thousands years. However, there is still lack of comprehensive active constituents profiling of this species throughout the Qinghai-Tibet Plateau (QTP). AIM OF STUDY: This study was designed to provide a comprehensive quality map of G.straminea germplasm based on twelve active constituents (loganic acid, gentiopicroside, swertiamarin, sweroside, 6-O-ß-D-glucosylgentiopicroside, oleanic acid, morroniside, trilobatin, isoorientin, isovite, Shanzhisidemethylester and quercetin) on the QTP. MATERIALS AND METHODS: G.straminea root samples collected throughout QTP in the flowering period were analyzed by the LC-MS/MS. Statistics analysis methods PCA, clustering and ecological regions analysis for G.straminea constituents differentiation was demonstrated. RESULTS: The active constituents varied greatly across the QTP; the majority of constituents were secoiridoid derivatives, with gentiopicroside being the most abundant compound. Most constituents were significantly affected by the latitudes and altitudes other than longitudes. PCA and hierarchical clustering analysis showed that all samples could be separated into six distinct groups, and 15 populations showed the highest constituent abundances. Further, geographical region analysis showed that the highest quality populations mainly located near the source region of Yellow River, especially in the Qinghai and Sichuan areas. Additionally, correlation analysis showed that there were relationships among genetiopicroside, loganic acid, and other compounds, which might be related to the enzymatic pathways involved in the metabolism of these constituents. CONCLUSION: LC-MS/MS method allowed separation of quality profiling of G.straminea on the QTP, 15 populations showed the highest constituent abundances. In six geographical groups, the highest quality populations mainly located near the source region of Yellow River, especially in the Qinghai and Sichuan areas, which may be due to the climate caused by the westerlies and Indian Ocean monsoons in the QTP.

Concentrations of the active constituents of the Tibetan folk medicine Qinjiao (Gentiana sect. Cruciata) within and between taxonomic species across the Qinghai-Tibetan Plateau.

The Tibetan folk medicine Qinjiao is traditionally used to treat various conditions, and its main active constituents comprise four iridoid glycosides, i.e., loganic acid, swertiamarin, gentiopicroside, and sweroside. The traditional crude medicine Qinjiao is derived from the dried roots of three species belonging to Gentiana sect. Cruciata (Gentianaceae) growing in the Qinghai-Tibetan Plateau (QTP). In this study, we determined by HPLC the contents of the four main active constituents in the dried roots collected from 83 localities at different altitudes across the QTP. The material was classified under the seven taxonomic species G. straminea, G. dahurica, G. crassicaulis, G. waltonii, G. officinalis, G. ihassica, and G. macrophylla. Our results suggested that the four constituents were present in the roots of all seven species for all localities, but their concentrations varied greatly within and between species. The level of gentiopicroside revealed to be the most dominant for all examined localities (2.1-12.4 mg/g), and G. macrophylla Pall. contained the highest concentration of all the four constituents at the species level. Except for loganic acid in G. officinalis, there was no significant correlation between the contents of these constituents and the altitude of the sampling localities. These results suggest that all species of all origins can be used as reliable resource for the crude medicine Qinjiao. However, a few species contain higher concentrations of the main active constituents, irrespective of their origin.

Morphology, genetic characterization and molecular phylogeny of pinworm Skrjabinema longicaudatum n. sp. (Oxyurida: Oxyuridae) from the endangered Tibetan antelope Pantholops hodgsonii (Abel) (Artiodactyla: Bovidae).

BACKGROUND: The Tibetan antelope Pantholops hodgsonii (Abel) (Artiodactyla: Bovidae) is an endangered species of mammal endemic to the Qinghai-Tibetan Plateau. Parasites and parasitic diseases are considered to be important threats in the conservation of the Tibetan antelope. However, our present knowledge of the composition of the parasites of the Tibetan antelope remains limited. METHODS: Large numbers of nematode parasites were collected from a dead Tibetan antelope. The morphology of these nematode specimens was observed using light and scanning electron microscopy. The nuclear and mitochondrial DNA sequences, i.e. small subunit ribosomal DNA (18S), large subunit ribosomal DNA (28S), internal transcribed spacer (ITS) and cytochrome c oxidase subunit 1 (cox1), were amplified and sequenced for molecular identification. Moreover, phylogenetic analyses were performed using maximum likelihood (ML) inference based on 28S and 18S + 28S + cox1 sequence data, respectively, in order to clarify the systematic status of these nematodes. RESULTS: Integrated morphological and genetic evidence reveals these nematode specimens to be a new species of pinworm Skrjabinema longicaudatum (Oxyurida: Oxyuridae). There was no intraspecific nucleotide variation between different individuals of S. longicaudatum n. sp. in the partial 18S, 28S, ITS and cox1 sequences. However, a high level of nucleotide divergence was revealed between the new species and its congeners in 28S (8.36%) and ITS (20.3-23.7%) regions, respectively. Molecular phylogenetic results suggest that the genus Skrjabinema should belong to the subfamily Oxyurinae (Oxyuroidea: Oxyuridae), instead of the subfamily Syphaciidae or Skrjabinemiinae in the traditional classification, as it formed a sister relationship to the genus Oxyuris. CONCLUSIONS: A new species of pinworm Skrjabinema longicaudatum n. sp. (Oxyurida: Oxyuridae) is described. Skrjabinema longicaudatum n. sp. represents the first species of Oxyurida (pinworm) and the fourth nematode species reported from the Tibetan antelope. Our results contribute to the knowledge of the species diversity of parasites from the Tibetan antelope, and clarify the systematic position of the genus Skrjabinema.

Comparison of Profiling of Hairy Root of Two Tibetan Medicinal Plants Przewalskia tangutica Maxim. and Anisodus tanguticus Maxim.

BACKGROUND: Tropane Alkaloids (TAs) are important drugs for curing many diseases in the medical industry. METHODS: To sustainably exploit TA resources in endangered traditional Tibetan herbs, the hairy root (HR) systems of Przewalskia tangutica Maxim. and Anisodus tanguticus Maxim. were compared under the same culture conditions. RESULTS: The results indicated that both the Agrobacterium rhizogenes strains and explants affected the HR induction frequency, MSU440, A4 and LBA9402 strains could induce hairy roots following infection of cotyledon and hypocotyl of A. tanguticus while LBA9402 could not induce HR on either explants of P. tangutica. The efficiency of LBA9402 was higher than A4 and MSU440 on A. tanguticus and A4 was better strain than MSU440 on P. tangutica. The hypocotyl explant was more suitable for P.tangutica and cotyledon explant was better for A.tangutica with a transformation frequency of 33.3% (P. tangutica) and 82.5% (A. tanguticus), respectively. In a flask reactor system, both the growth curves of HR for two species both appeared to be "S" curve; however, the HR of P. tangutica grew more rapidly than that of A. tanguticus, and the latter accumulated more biomass than the former. As the culture volume increased, the HR proliferation coefficient of both the species increased. HPLC analysis results showed that the content of TAs in the HR of P. tangutica was 257.24mg/100g·DW, which was more than that of A. tanguticus HR (251.08mg/100g·DW), and the anisodamine in the Pt- HR was significantly higher than that in At-HR. Moreover, tropane alkaloids in the HR of the two species were all significantly higher than that of the roots of aseptic seedlings. CONCLUSION: Our results suggest that HR of P. tangutica and A. tanguticus both could provide a useful platform for sustainable utilization of two Tibetan medicinal plants in the Qinghai-Tibetan Plateau in the future.

Characterization of the complete chloroplast genome of Pterygocalyx volubilis (Gentianaceae).

Pterygocalyx volubilis Maxim. (Gentianaceae) is a traditional Chinese medicine, and its whole grass is used in the treatment of pulmonary tuberculosis and other conditions. Here, the complete chloroplast genome sequence of P. volubilis was reported based on the Illumina HiSeq Platform. The chloroplast genome genome is 154,365 bp in length, containing a pair of inverted repeated (IR) regions (25,928 bp) that are separated by a large single copy (LSC) region of 84,033 bp, and a small single copy (SSC) region of 18,476 bp. Moreover, a total of 130 functional genes were annotated, including 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. In the maximum-likelihood (ML) phylogenetic tree, Pterygocalyx clustered with the genus Swertia. This sequenced chloroplast genome of P. volubilis supports that Pterygocalyx belongs to subtribe Swertiinae.

Complete plastome sequence of Eustoma grandiflorum (Gentianaceae), a popular cut flower.

Eustoma grandiflorum (Raf.) Shinners is a popular cut flower due to its beautiful morphological characteristics and extended vase life. Here, the complete plastome sequence of E. grandiflorum was reported based on the Illumina HiSeq Platform. The plastome sequence is 154,230 bp in length with a typical quadripartite structure, containing a pair of inverted repeated (IR) regions (25,755 bp) that are separated by a large single copy (LSC) region of 84,297 bp, and a small single copy (SSC) region of 18,423 bp. A total of 130 functional genes were annotated, including 84 protein-coding genes, 38 tRNA genes, and 8 rRNA genes. The complete plastome sequence of E. grandiflorum will provide a valuable resource for its garden utilization and the phylogenetic studies of Gentianaceae.

Characterization of the complete chloroplast genome of traditional Tibetan herb, Rheum Pumilum Maxim. (Polygonaceae).

The complete chloroplast genome sequence of traditional Tibetan herb, Rheum pumilum Maxim. was analyzed. The complete chloroplast genome of R. pumilum is 162,213 bp in size and has a 27.27% GC content. In the typical circular quadripartite structure, there was a pair of inverted repeat (IR) regions with 31,023 bp in length, which separated by a large single-copy (LSC) region (87,424 bp) and a small single-copy (SSC) region (12,743 bp). The chloroplast genome of R. pumilum contained 131 unigenes, which was composed of 86 protein-coding genes, 37 tRNA and 8 rRNA genes. Moreover, 238 SSRs were identified and 58.8% of them existed in LSC region. A maximum likelihood (ML) phylogenetic analysis based on chloroplast genomes indicated that R. pumilum was closely related to R. pulmatum, R. tangutica, and R. officinale. Our results would provide a valuable resource for resource utilization and the phylogenetic studies of Rheum in Polygonaceae.

Complete chloroplast genome of Meconopsis integrifolia (Papaveraceae).

Meconopsis integrifolia (Maxim.) Franch is a traditional Tibetan medicinal material. In this study, we sequenced and assembled the complete chloroplast genome of M. integrifolia. The chloroplast genome is 152,714 bp in length, containing a pair of inverted repeated (IR) region of 25,627 bp that are separated by a large single copy (LSC) region of 83,706 bp, and a small single copy (SSC) region of 17,754 bp. Moreover, a total of 126 functional genes were annotated, including 86 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. In the maximum likelihood phylogenetic tree, M. integrifolia clustered closely with three Papaver species.

Two new diterpenes from Euphorbia kansuensis.

Two new lathyrane diterpenes, 3beta,5alpha-dihydroxy-15beta-cinnamoyloxy-14-oxolathyra-6Z,12E -diene (1) and 3beta,5alpha,20-trihydroxy-15beta-cinnamoyloxy-14-oxolathyra-6Z,12E-diene (2), were isolated from the roots of Euphorbia kansuensis. Their structures were determined by spectroscopic methods.

Genetic transformation of the endangered Tibetan medicinal plant Przewalskia tangutica Maxim and alkaloid production profiling revealed by HPLC.

To achieve a high yield of tropane alkaloids (TA) and exploit the alpine plant sustainably, an optimized protocol for induction and establishment of hairy roots culture of Prezwalskia tangutica Maxim was developed through selection of appropriate Agrobacterium strain and the explant type. The hypocotyl is more readily facile to induce the HR than the cotyledon is when infected with the three different agrobacterium strains. MUS440 has an efficiency (of up to 20%), whereas the ATCC10060 (A4) can induce HR on both types of explants with the highest frequency (33.33%), root length (21.17 ± 2.84 cm), and root number (10.83 ± 1.43) per explant than the other strains. The highest HR production resulted from using hypocotyl as explants. Independent transformed HR was able to grow vigorously and to propagate on a no-hormone 1/2MS liquid medium. The presence of pRi rolB gene in transformation of HR was confirmed by PCR amplification. In the liquid medium, the HR growth curve appeared to be "S" shaped, and ADB had increased to 4.633 g/l. Moreover, HPLC analysis showed that HR lines have an extraordinary ability to produce atropine (229.88 mg/100 g), anisodine (4.09 mg/100 g), anisodamine (12.85 mg/100 g), and scopolamine (10.69 mg/100 g), which were all more significant than the control roots. In conclusion, our study optimized the culture condition and established a feasible genetics reactor for P. tangutica green exploration and biological study in the alpine region.

Quantitative iTRAQ Proteomics Revealed Possible Roles for Antioxidant Proteins in Sorghum Aluminum Tolerance.

Aluminum (Al) toxicity inhibits root growth and limits crop yields on acid soils worldwide. However, quantitative information is scarce on protein expression profiles under Al stress in crops. In this study, we report on the identification of potential Al responsive proteins from root tips of Al sensitive BR007 and Al tolerant SC566 sorghum lines using a strategy employing iTRAQ and 2D-liquid chromatography (LC) coupled to MS/MS (2D-LC-MS/MS). A total of 771 and 329 unique proteins with abundance changes of >1.5 or <0.67-fold were identified in BR007 and SC566, respectively. Protein interaction and pathway analyses indicated that proteins involved in the antioxidant system were more abundant in the tolerant line than in the sensitive one after Al treatment, while opposite trends were observed for proteins involved in lignin biosynthesis. Higher levels of ROS accumulation in root tips of the sensitive line due to decreased activity of antioxidant enzymes could lead to higher lignin production and hyper-accumulation of toxic Al in cell walls. These results indicated that activities of peroxidases and the balance between production and consumption of ROS could be important for Al tolerance and lignin biosynthesis in sorghum.

De novo sequencing transcriptome of endemic Gentiana straminea (Gentianaceae) to identify genes involved in the biosynthesis of active ingredients.

Gentiana straminea is a popular Tibetan medicine that has been used for thousands of years in China to treat various diseases and conditions. Although it has multiple pharmaceutical purposes and important economic plant resource in China, transcriptome and molecular base still known limited. In flowering season, samples were collected from different tissues, using the NGS Illumina. Solexa platform, about 58.85 million sequencing reads were generated and assembled de novo, yielding 78,764 high quality unigenes with an average length of 1090bp. Gene Ontology (GO), KEGG pathway mapping showed that 49,033 of these were identified as putative homologs of annotated sequences in the protein databases. Among them, candidate genes associated with iridoid, flavonoid and anthocyanin were identified. Further the key enzymes involved to iridoid and flavonoid synthesis pathway were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) on different tissues, the flower and root had the higher expression than leaves. In addition, 7591 SSR markers were identified from the unigenes of the G. straminea transcriptome. The foundation of G. straminea provided the important resource for facilitating to study molecular and functional genomics of it and related this species on the Qinghai-Tibet Plateau.

Spatial variation profiling of four phytochemical constituents in Gentiana straminea (Gentianaceae).

Gentiana straminea is the famous Tibetan folk medicine thought to cure various diseases. Historically, the Qinghai-Tibetan region has been considered as the geo-authentic production area of "Mahua Jiao," where large quantities of the medicine are grown. However, there is still little known about the phytochemical constituent spatial variation of this species. In order to find the differences between the main phytochemical constituents of G. straminea and to provide comprehensive information for quality evaluation, four main bioactive compounds (loganic acid, swertiamarin, gentiopicroside and sweroside) were analysed in 26 populations grown in areas with elevations ranging from 2320 to 4720 m across the Qinghai-Tibetan Plateau. The results showed that the four phytochemical constitutes' concentrations varied greatly in the spatial profiling of the Qinghai-Tibetan region. Throughout the range of distribution of this species, no altitudinal, latitudinal or longitudinal trends have proven to be significant in any of the four constitutes' concentrations or their summation. Furthermore, hierarchical clustering analysis and statistical tests showed that four populations (Liu0609-18, Liu0609-15, Liu2006-13-9 and Liu0609-22) had total constitute contents that were higher than other populations. The spatial profiling of the four phytochemical constituents suggests that the geo-authentic producing area of this species exists at a few regions within the Qinghai province, which could be attributed to specific environmental or genetic factors.

Duplication and adaptive evolution of the COR15 genes within the highly cold-tolerant Draba lineage (Brassicaceae).

Plants have evolved diverse adaptive mechanisms that enable them to tolerate abiotic stresses, to varying degrees, and such stresses may have strongly influenced evolutionary changes at levels ranging from molecular to morphological. Previous studies on these phenomena have focused on the adaptive evolution of stress-related orthologous genes in specific lineages. However, heterogenetic evolution of the paralogous genes following duplication has only been examined in a very limited number of stress-response gene families. The COR15 gene encodes a low molecular weight protein that plays an important role in protecting plants from cold stresses. Although two different copies of this gene have been found in the model species, Arabidopsis thaliana, evolutionary patterns of this small gene family in plants have not been previously explored. In this study, we cloned COR15-like sequences and performed evolutionary analyses of these sequences (including those previously reported) in the highly cold-tolerant Draba lineage and related lineages of Brassicaceae. Our phylogenetic analyses indicate that all COR15-like sequences clustered into four clades that corresponded well to the morphological lineages. Gene conversions were found to have probably occurred before/during the divergence of Brassica and Draba lineage. However, repeated, independent duplications of this gene have occurred in different lineages of Brassicaceae. Further comparisons of all sequences suggest that there have been significant inter-lineage differences in evolutionary rates between the duplicated and original genes. We assessed the likelihood that the differences between two well-supported gene subfamilies that appear to have originated from a single duplication, COR15a and COR15b, within the Draba lineage have been driven by adaptive evolution. Comparisons of their non-synonymous/synonymous substitution ratios and rates of predicted amino acid changes indicate that these two gene groups are evolving under different selective pressures and may be functionally divergent. This functional divergence was confirmed by comparing site-specific shifts in evolution indexes of the two groups of predicted proteins. The evidence of differential selection and possible functional divergence suggests that the duplication may be of adaptive significance, with possible implications for the explosive diversification of the Draba lineage during the cooling Quaternary stages and the following worldwide colonization of arid alpine and artic regions.

[CO2 flux characteristics from degenerated mat cryo-sod soil during plant growing period].

The carbon dioxide (CO2) emission rate was studied in the degenerated mat cryo-sod soil covered with alpine Kobresia humilis meadow at the Haibei alpine meadow ecosystem research station, with CID-301 ps CO2 analytical instrument during plant growth period (May-Sep, in 1998). The results showed that the CO2 emission rate had obvious daily variation and seasonal dynamics. The maximum rate of CO2 emission appeared at 12:00-14:00, and the minimum rate appeared at 6:00-8:00. The max daily amplitude was 462.49 mg.m-2.h-1, while the minimum daily amplitude was 114.97 mg.m-2.h-1. The CO2 emission rate varied with phonological periods, and the order was exuberance > withering > green up. The maximum daily average value was 480.76 mg.m-2.h-1 (Aug.18th), and the minimum daily average value was 140.77 mg.m-2.h-1 (May.9th). Correlation analysis showed that there was a significant relationship between CO2 emission rate and air temperature, soil surface temperature and soil temperature in 5 cm, 10 cm, 15 cm, 20 cm, and 30 cm. Temperature was the dominant factor that affected the CO2 emission rate in degenerated mat cryo-sod soil.