Berberine chloride suppresses pancreatic adenocarcinoma proliferation and growth by targeting inflammation-related genes: an in silico analysis with in vitro and vivo validation.

PURPOSE: Targeting inflammatory crosstalk between tumors and their microenvironment has emerged as a crucial method for suppressing pancreatic adenocarcinoma (PAAD) progression. Berberine (BBR) is a natural pentacyclic isoquinoline alkaloid known for its anti-inflammatory and antitumor pharmacological effects; however, the mechanism underlying PAAD suppression remains unclear. We aim to investigate the effects of BBR on PAAD progression and their underlying mechanisms. METHODS: The prognostic value of inflammation-related genes in PAAD was assessed using bioinformatics analyses, then the pharmacological effects and potential mechanisms of BBR on PAAD will be investigated in silico, in vitro, and in vivo. RESULTS: Fifty-eight prognostic inflammation-related genes were identified in PAAD, which were shown to have good sensitivity and specificity using a novel inflammation-related gene risk-prognosis prediction model. Among these, four candidate genes (CAPS3, PTGS2, ICAM1, and CXCR4) were predicted as targets of BBR in PAAD in silico. Molecular docking simulations showed that the four key targets docked well with BBR. Further BBR treatment suppressed cell proliferation, colony formation, and induced cell cycle arrest in vitro. Moreover, BBR exhibited a significant tumor-suppressive effect in murine subcutaneous xenografts without macroscopic hepatic and renal toxicities. In addition, BBR downregulated CAPS3, PTGS2, ICAM1, and CXCR4 protein expression. CONCLUSION: This study not only elucidated the prognostic value of inflammation-related genes in PAAD but also demonstrated the potential of BBR to inhibit PAAD by targeting these genes.

Keep a watchful eye on methionine adenosyltransferases, novel therapeutic opportunities for hepatobiliary and pancreatic tumours.

Methionine adenosyltransferases (MATs) synthesize S-adenosylmethionine (SAM) from methionine, which provides methyl groups for DNA, RNA, protein, and lipid methylation. MATs play a critical role in cellular processes, including growth, proliferation, and differentiation, and have been implicated in tumour development and progression. The expression of MATs is altered in hepatobiliary and pancreatic (HBP) cancers, which serves as a rare biomarker for early diagnosis and prognosis prediction of HBP cancers. Independent of SAM depletion in cells, MATs are often dysregulated at the transcriptional, post-transcriptional, and post-translational levels. Dysregulation of MATs is involved in carcinogenesis, chemotherapy resistance, T cell exhaustion, activation of tumour-associated macrophages, cancer stemness, and activation of tumourigenic pathways. Targeting MATs both directly and indirectly is a potential therapeutic strategy. This review summarizes the dysregulations of MATs, their proposed mechanism, diagnostic and prognostic roles, and potential therapeutic effects in context of HBP cancers.

Integrating network pharmacology and experimental models to investigate the efficacy of QYHJ on pancreatic cancer.

ETHNOPHARMACOLOGICAL RELEVANCE: The Qingyihuaji decoction (QYHJ) is composed of seven herbs: Scutellaria barbata D.Don (Banzhilian, HSB), Gynostemma pentaphyllum (Thunb.) Makino (Jiaogulan, GP), Oldenlandia diffusa (Willd.) Roxb. (Baihuasheshecao, HDH), Ganoderma lucidum (Leyss. ex Fr.) Karst. (Lingzhi, GL), Myristica fragrans Houtt. (Doukou, AK), and Amorphophallus kiusianus (Makino) Makino (Sheliugu, RA), and Coix lacryma-jobi var. ma-yuen (Rom.Caill.) Stapf (Yiyiren, CL). QYHJ has been reported to exhibit clinical efficacy in the treatment of pancreatic adenocarcinoma (PAAD). However, the molecular mechanism remains unclear. AIM OF THE STUDY: This study explores the therapeutic mechanism of QYHJ in the treatment of PAAD using network pharmacology to identify related targets and pathways in vivo and in vitro. MATERIALS AND METHODS: The bioactive compounds of QYHJ were retrieved and screened using the ADME network pharmacology approach, followed by compound-target prediction and overlapping genes between PAAD oncogenes and QYHJ target genes. The compound-target-pathway network was established using The KEGG pathway, GO analysis, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) analysis to identify potential action pathways. The effects of QYHJ on PAAD were evaluated in vivo and in vitro, and the predicted targets and potential pathways related to QYHJ in PAAD treatment were evaluated using qRT-PCR and immunoblotting. RESULTS: A total of 68 bioactive compounds of QYHJ fulfilled the ADME screening criterion, and their respective 242 target genes were retrieved. The compound-target-disease network identified 11 possible target genes. The KEGG pathway analysis showed significant enrichment of pathways in cancers, involving regulating cancer-related pathways of inflammation, oxidative stress, and apoptosis. Furthermore, QYHJ inhibited PAAD growth in vivo; suppressed cell proliferation, invasion, and migration of PAAD; and induced cellular apoptosis in vitro. The qRT-PCR results showed that QYHJ suppressed the mRNA expression of ICAM1, VCAM1, and Bcl2, and increased that of HMOX1 and NQO1. Immunoblotting revealed changes in the PI3K/AKT/mTOR, Keap1/Nrf2/HO-1/NQO1, and Bcl2/Bax pathways upon QYHJ treatment. CONCLUSIONS: QYHJ can suppress PAAD growth and progression through various mechanisms, including anti-inflammation and apoptosis-induction.

Evidence-Based Dampness-Heat ZHENG (Syndrome) in Cancer: Current Progress toward Establishing Relevant Animal Model with Pancreatic Tumor.

Cancer is one of the deadliest diseases affecting the health of human beings. With limited therapeutic options available, complementary and alternative medicine has been widely adopted in cancer management and is increasingly becoming accepted by both patients and healthcare workers alike. Chinese medicine characterized by its unique diagnostic and treatment system is the most widely applied complementary and alternative medicine. It emphasizes symptoms and ZHENG (syndrome)-based treatment combined with contemporary disease diagnosis and further stratifies patients into individualized medicine subgroups. As a representative cancer with the highest degree of malignancy, pancreatic cancer is traditionally classified into the "amassment and accumulation". Emerging perspectives define the core pathogenesis of pancreatic cancer as "dampness-heat" and the respective treatment "clearing heat and resolving dampness" has been demonstrated to prolong survival in pancreatic cancer patients, as has been observed in many other cancers. This clinical advantage encourages an exploration of the essence of dampness-heat ZHENG (DHZ) in cancer and investigation into underlying mechanisms of action of herbal formulations against dampness-heat. However, at present, there is a lack of understanding of the molecular characteristics of DHZ in cancer and no standardized and widely accepted animal model to study this core syndrome in vivo. The shortage of animal models limits the ability to uncover the antitumor mechanisms of herbal medicines and to assess the safety profile of the natural products derived from them. This review summarizes the current research on DHZ in cancer in terms of the clinical aspects, molecular landscape, and animal models. This study aims to provide comprehensive insight that can be used for the establishment of a future standardized ZHENG-based cancer animal model.

Infection with a human-derived enteroinvasive Escherichia coli strain altered intestinal barrier function in guinea pigs.

BACKGROUND/AIMS: The aim was to characterize a bacterium causing intestinal mucosal barrier damage and to identify the possible invasion mechanism. MATERIALS AND METHODS: The intestinal permeability and tight junction protein levels were detected in guinea pigs infected with Escherichia coli D-09 via immunofluorescence analysis and western blotting. In order to explain this invasion mechanism at the gene level, whole genome sequencing analysis was performed on this bacterium. RESULTS: The results showed an increased intestinal permeability and upregulated expression of the leaky protein claudin-2 in both the colon and liver of the infected animals. In addition, the draft genome of E. coli D-09 comprised 42 scaffolds (size, > 645 bp) with a total size of 4,679,567 bp. A total of 4379 protein coding genes were identified, which contained 45 antibiotic resistance and 86 virulence-related genes and covered 88.0% of the whole genome. CONCLUSIONS: This study verified that the human-derived enteroinvasive E. coli strain could destroy intestinal barrier function in guinea pigs. Additionally, our data first characterized the genome features of E. coli O124:K72 D-09, which may provide new insights into the possible invasion mechanism.

[Distribution and enrichment characteristics of soil nutrients in the nebkhas profile of Nitraria tangutorum in Gahai Lake Area, Qaidam Basin.] / æŸ´è¾¾æœ¨ç›†åœ°å°•æµ·æ¹–åŒºç™½åˆºçŒä¸›æ²™å †å‰–é¢åœŸå£¤å »åˆ†çš„åˆ†å¸ƒå’Œå¯Œé›†ç‰¹å¾.

As a special bio-geomorphic landscape in the Qaidam desert area, Nitraria tangutorum nebkhas play a critical role in fixing quicksand, improving soil quality, and maintaining the stability of regional ecological environment. Taking the N. tangutorum nebkhas with coverage of approximately 15%, 25%, 45% and 60% in Gahai Lake area of Qaidam Basin as the research objects, we analyzed the vertical distribution and enrichment characteristics of soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkali-hydrolyzable nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the contents of SOM, TN, TP, TK, AN, AP and AK varied in the range of 1.67-10.22 g·kg-1, 0.05-0.42 g·kg-1, 0.31-0.54 g·kg-1, 15.87-18.84 g·kg-1, 2.26-11.68 mg·kg-1, 0.80-15.00 mg·kg-1 and 45-161 mg·kg-1, respectively. Vertically, soil nutrients in the N. tangutorum nebkhas with 15% coverage showed a decreasing trend first then increased, and then decreased again with the increase of soil depth, except for TP, which did not show any significant change. In the nebkhas with 25%, 45% and 60% coverage, SOM, TN, AN, TP and AP all showed a decreasing trend with increasing soil depth ,whereas TK and AK did not change significantly with soil layer. Above the nebkhas ground level of N. tangutorum, SOM, TN, TK, AN, AP and AK were all enriched, especially in the surface layer.Aamong all the nutrients, the enrichment rate of AN reached 5.19. In addition, below the nebkhas ground level of N. tangutorum, TN, AN, TK, AK and AP also showed enrichment. SOM, TN, AN, TP, AP, TK and AK were all significantly positively correlated with soil water content, and negatively correlated with altitude. All nutrients except TP were mainly affected by altitude. In conclusion, soil nutrient content of N. tangutorum nebkhas was the highest in the surface layer, the enrichment effect of which was not only reflected in the interior of the nebkhas, but also below the ground level of the nebkhas. Our results could provide reference for the scientific utilization of N. tangutorum nebkhas and ecological environment protection in Qaidam Basin area.

Matrine injection inhibits pancreatic cancer growth via modulating carbonic anhydrases- a network pharmacology-based study with in vitro validation.

ETHNOPHARMACOLOGICAL RELEVANCE: Matrine injection is a complex mixture of plant bioactive substances extracted from Sophora flavescens Aiton and Smilax glabra Roxb. Since its approval by the Chinese Food and Drug Administration (CFDA) in 1995, Matrine injection has been clinically used as a complementary and alternative treatment for various cancers; however, the underlying mechanism of pancreatic cancer treatment is yet to be elucidated. AIM OF THE STUDY: The present study explores the potential mechanism of matrine injection on pancreatic cancer through network pharmacology technique and in vitro experimental validation. MATERIALS AND METHODS: Genes differentially expressed in pancreatic cancer were obtained from the Gene Expression Omnibus (GEO) database (GSE101448). The potential active components of matrine injection were selected following a literature search, and target prediction was performed by the SwissTarget Prediction database. Overlapping genes associated with survival were screened by the Gene Expression Profiling Interactive Analysis (GEPIA) database. In vitro experimental validation was performed with cell counting kit-8 (CCK-8) assay, apoptosis detection, cell cycle analysis, immunoblotting, and co-immunoprecipitation of the identified proteins. RESULTS: One thousand seven hundred genes differentially expressed among pancreatic tumor and non-tumor tissues were screened out. Sixteen active components and 226 predicted target genes were identified in matrine injection. A total of 25 potential target genes of matrine injection for the treatment of pancreatic cancer were obtained. Among them, the prognostic target genes carbonic anhydrase 9 (CA9) and carbonic anhydrase 12 (CA12) based on the GEPIA database are differently expressed in tumors compared to adjacent normal tissue. In vitro experiments, the results of CCK-8 assay, apoptosis and cell cycle analysis, immunoblotting, and co-immunoprecipitation showed that matrine injection inhibited Capan-1 and Mia paca-2 proliferation, arrested the cell cycle at the S phase, and induced apoptosis through up-regulated CA12 and down-regulated CA9. CONCLUSIONS: In this study, bioinformatics and network pharmacology were applied to explore the treatment mechanism on pancreatic cancer with matrine injection. This study demonstrated that matrine injection inhibited proliferation, arrested the cell cycle, and induced apoptosis of pancreatic cancer cells. The mechanism may be related to the induction of CA12 over-expression, and CA9 reduced expression. As novel targets for pancreatic cancer treatment, Carbonic anhydrases require further study.

HELLS serves as a poor prognostic biomarker and its downregulation reserves the malignant phenotype in pancreatic cancer.

BACKGROUND: SMARCAs, belonged to SWI/SNF2 subfamilies, are critical to cellular processes due to their modulation of chromatin remodeling processes. Although SMARCAs are implicated in the tumor progression of various cancer types, our understanding of how those members affect pancreatic carcinogenesis is quite limited and improving this requires bioinformatics analysis and biology approaches. METHODS: To address this issue, we investigated the transcriptional and survival data of SMARCAs in patients with pancreatic cancer using ONCOMINE, GEPIA, Human Protein Atlas, and Kaplan-Meier plotter. We further verified the effect of significant biomarker on pancreatic cancer in vitro through functional experiment. RESULTS: The Kaplan-Meier curve and log-rank test analyses showed a positive correlation between SMARCA1/2/3/SMARCAD1 and patients' overall survival (OS). On the other hand, mRNA expression of SMARCA6 (also known as HELLS) showed a negative correlation with OS. Meanwhile, no significant correlation was found between SMARCA4/5/SMARCAL1 and tumor stages and OS. The knockdown of HELLS impaired the colony formation ability, and inhibited pancreatic cancer cell proliferation by arresting cells at S phase. CONCLUSIONS: Data mining analysis and cell function research demonstrated that HELLS played oncogenic roles in the development and progression of pancreatic cancer, and serve as a poor prognostic biomarker for pancreatic cancer. Our work laid a foundation for further clinical applications of HELLS in pancreatic cancer.

Qing-Yi Decoction in the Treatment of Acute Pancreatitis: An Integrated Approach Based on Chemical Profile, Network Pharmacology, Molecular Docking and Experimental Evaluation.

Background: Qing-Yi Decoction (QYD) is a classic precompounded prescription with satisfactory clinical efficacy on acute pancreatitis (AP). However, the chemical profile and overall molecular mechanism of QYD in treating AP have not been clarified. Methods: In the present study, a rapid, simple, sensitive and reliable ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS)-based chemical profile was first established. An integration strategy of network pharmacology analysis and molecular docking based identified ingredients was further performed to screen out the potential targets and pathways involved in the treatment of QYD on AP. Finally, SD rats with acute pancreatitis were constructed to verify the predicted results through a western blot experiment. Results: A total of 110 compounds, including flavonoids, phenolic acids, alkaloids, monoterpenes, iridoids, triterpenes, phenylethanoid glycosides, anthraquinones and other miscellaneous compounds were identified, respectively. Eleven important components, 47 key targets and 15 related pathways based on network pharmacology analysis were obtained. Molecular docking simulation indicated that ERK1/2, c-Fos and p65 might play an essential role in QYD against AP. Finally, the western blot experiments showed that QYD could up-regulate the expression level of ERK1/2 and c-Fos, while down-regulate the expression level of p65. Conclusion: This study predicted and validated that QYD may treat AP by inhibiting inflammation and promoting apoptosis, which provides directions for further experimental studies.

[Soil anti-erodibility of abandoned lands during different succession stages of plant community in hilly-gullied region of the Loess Plateau: Take Fangta small watershed as an example].

Field survey and laboratory experiment were conducted to study the soil anti-erodibility of abandoned croplands during different vegetation succession stages in hilly-gullied region of the Loess Plateau, based on the analysis of soil particle composition, size distribution and group characteristics, soil aggregate fractal dimensions and stability. The results showed that in the earlier stages of succession from annual to perennial herbs in abandoned croplands, soil size distribution changed a little bit, the fractal dimension of soil particle increased, soil structure improved, fractal dimension and damage percent of soil aggregate structure decreased, soil stability increased, thus soil anti-erodibility increased. Therefore, natural restoration of vegetation is of great significance to improve the soil structure, increase soil erosion resistance, reduce soil erosion and promote sustainable development of regional ecological environment.

An approach for detecting five typical vegetation types on the Chinese Loess Plateau using Landsat TM data.

Remote sensing can provide large-scale spatial data for the detection of vegetation types. In this study, two shortwave infrared spectral bands (TM5 and TM7) and one visible spectral band (TM3) of Landsat 5 TM data were used to detect five typical vegetation types (communities dominated by Bothriochloa ischaemum, Artemisia gmelinii, Hippophae rhamnoides, Robinia pseudoacacia, and Quercus liaotungensis) using 270 field survey data in the Yanhe watershed on the Loess Plateau. The relationships between 200 field data points and their corresponding radiance reflectance were analyzed, and the equation termed the vegetation type index (VTI) was generated. The VTI values of five vegetation types were calculated, and the accuracy was tested using the remaining 70 field data points. The applicability of VTI was also tested by the distribution of vegetation type of two small watersheds in the Yanhe watershed and field sample data collected from other regions (Ziwuling Region, Huangling County, and Luochuan County) on the Loess Plateau. The results showed that the VTI can effectively detect the five vegetation types with an average accuracy exceeding 80 % and a representativeness above 85 %. As a new approach for monitoring vegetation types using remote sensing at a larger regional scale, VTI can play an important role in the assessment of vegetation restoration and in the investigation of the spatial distribution and community diversity of vegetation on the Loess Plateau.

[Characteristics of seed rain on abandoned slopes in the hilly-gullied Loess Plateau, Northwest China].

The objective of this study was to analyze the dynamic characteristics of seed rain on abandoned slopes in the hilly-gullied Loess Plateau region and identify the relationship between seed rain and standing vegetation. Three abandoned slopes were chosen as sampling sites in Zhifanggou watershed. Thirty traps were installed at each site to collect seed rain from October 2010 to April 2013. Standing vegetation was surveyed to identify dominant species in August 2011 and 2012, respectively. Thirty-seven species belonging to seventeen families were identified in the seed rain, and the dominant species, i.e., Lespedeza davurica, Astragalus scaberrimus, Setaria viridis, Cleistogenes squarrosa, Stipa bungeana, Bothriochloa ischcemum, Artemisia scoparia, A. gmelinii, and Heteropappus altaicus, took up to 95.8% of the total seed rain. Three species in seed rain were not found in the standing vegetation. The Sorensen similarity index between seed rain and standing vegetation was 0.77. Seed rain densities were 3737 and 6449 seeds · m(-2) in May 2011-April 2012 and May 2012-April 2013, respectively, and alternate bearing existed. During the study period, seed rain from different positions varied from 3853 to 37923 seeds · m(-2) and belonged to 7-15 species. The results indicated the space limitation of seed dispersal. Seed rain densities were in the middle of the pack compared with similar ecosystems in other studies. High temporal and spatial heterogeneity of seed rain was observed because of rainfall, microtopography and so on.

[Seasonal dynamics and vertical distribution pattern of bud bank in different erosion environments on hilly-gully Loess Plateau of Northwest China].

This paper studied the vegetation composition, bud composition, and the seasonal dynamics and vertical distribution pattern of bud bank in five erosion environments (sunny gully slope, sunny hilly slope, hilltop, shady hilly slope, and shady gully slope) on the hilly-gully Loess Plateau of North Shaanxi. In the study area, the perennial species with perennial bud bank accounted for 80.3% of the total species, while the annual species with seasonal bud bank took up 19.7% of the total. In vegetation turning-green season, there was a relatively large perennial bud bank stock on the sunny hilly-gully slope where serious erosion occurred, while seasonal bud bank showed a higher bud bank density in blossom and fruit-setting season on the hilltop and two shady slopes where soil erosion intensity was relatively gentle. The proportion of underground bud bank to total perennial bud bank in different erosion environments was relatively stable. On the land surface, the perennial bud bank stock was larger on the sunny slope where the soil disturbance often occurred, whereas the seasonal bud bank stock was larger on the shady slope and hilltop. Due to the different species composition of plant communities in different erosion environments, in addition to the disturbance of soil erosion and the seasonal plant regeneration, the seasonal dynamics and vertical distribution pattern of bud bank changed. It was suggested that bud bank played an important role in the vegetation regeneration after the disturbance of soil erosion on the hilly-gully Loess Plateau of North Shaanxi.

Relationship between seedling and mature vegetation on the hilly-gullied Loess Plateau.

Seedling is an indispensable stage in plant cycle life, and seedling survival is important during natural vegetation restoration, especially on the Loess Plateau. In 2007, we selected 4 plots of Artemisia scoparia communities (ASC) and 4 plots of Artemisia gmelinii + Artemisia giraldii communities (AGC), examined seedling richness, diversity during the rainy season, and examined mature vegetation richness, coverage, and frequency in August. The results showed that seedlings density of ASC were 29 n m(-2), 33 n m(-2), 20 n m(-2) and 31 n m(-2) in July to October respectively, and that of AGC were 14 n m(-2), 12 n m(-2), 6 n m(-2) and 9 n m(-2) respectively; A. scoparia seedlings represented 53.2% of the total seedlings in ASC, the dominant species in AGC only account for less than 5% of the total seedlings. Most of the seedlings found were belonged to Compositae, Leguminoseae and Gramineae; 80% of seedlings in ASC were mainly comprised of A. scoparia and Lespedeza davurica, while in AGC that consisted of more than 6 species, such as L. davurica, Sophora viciifolia, Dracocephalum moldavicaand, A. gmelinii, Patrinia heterophylla, Heteropappus altaicus so on. Sørensen similarity index between monthly seedlings was approximately 0.47 in ASC and 0.35 in AGC; Sørensen similarity index between seedlings and mature vegetation ranged from 0.18 to 0.34 in ASC, and varied from 0.26 to 0.39 in AGC. These results suggested that seedling establishment would be a bottleneck for natural vegetation restoration when seed supply and seedling emergence were possible.

[Ecological adaptability of leaf epidermis of erosion-resistant plants in hilly-gully area of Loess Plateau, Northwest China].

By the temporary slide method of leaf epidermis, an observation was made on the morphological characteristics of the leaf epidermis of six erosion-resistant plant species in different soil erosion environments (gully, inter-gully, and inter-gully artificial Robinia pseudoacacia forest land) in hilly-gully area of Loess Plateau. Compared with those in the gully, the stomata aperture, stomata density, stomata index, stomata apparatus length/width plasticity, stomata apparatus area plasticity, epidermal hair density, and epidermal cell density of the leaf upper and lower epidermis of the plants in the inter-gully were 93.8% and 90.4%, 66.8% and 76.6%, 17.9% and 9.8%, 36.4% and 47.1%, 42.3% and 43.9%, 199.4% and 98.2%, and 46.5% and 50.1% higher, respectively; while in the inter-gully artificial R. pseudoacacia forest land, the same morphological indices of the leaf upper and lower epidermis of the plants were 66.7% and 106.7%, 20.5% and 45.8%, 11.9% and 11.9%, 37.9% and 41.3%, 19.8% and 21.2%, 113.1% and 52.2%, and 10.8% and 28.1% higher than those in the gully, respectively. The epidermal hair length and epidermal cell area of the leaf upper and lower epidermis of the plants in the inter-gully were 58.8% and 29.7%, and 40.3% and 37.0% lower than those in the gully, and the same morphological indices of the leaf upper and lower epidermis of the plants in the intergully artificial R. pseudoacacia forest land were respectively 25.0% and 23.6%, and 22.2% and 19.2% lower than those in the gully, respectively. The results suggested that the erosion-resistant plants in the study area were able to adapt to various soil erosion environments by increasing their leaf stomata aperture, stomata density, stomata index, stomata apparatus length/width plasticity, stomata apparatus area plasticity, epidermal hair density, and epidermal cell density, and by reducing their epidermal hair length and epidermal cell area.

Germinable soil seed banks and the restoration potential of abandoned cropland on the Chinese hilly-gullied loess plateau.

Poor vegetation cover is generally considered to be a major factor causing soil erosion on the Loess Plateau in China. It has been argued that tree planting restoration is ineffective, and natural re-vegetation is an alternative ecological solution for restoring abandoned cropland and controlling soil erosion. The aims of this study were to investigate the characteristics of soil seed banks and to assess the natural restoration potential of abandoned cropland in the hilly-gullied Loess Plateau. The soil seed bank was identified by the germination method with the soil samples, which were collected at four sampling times (April, August, and October 2005 and August 2006) from 12 plots abandoned 3-30 years prior to sampling. The seed bank densities of all of the samples in the 0-10 cm soil layer varied from 1,067 ± 225 to 14,967 ± 1,606 seeds m(-2). Fifty-one species (24 annual and 27 perennial species) belonging to 18 families were identified, and 39% of these species belonged to the families Compositae and Gramineae. The pioneer species Artemisia scoparia dominated the seed bank, with an average seed density of 3,722 seeds m(-2), and accounted for 74.4% of the seeds in the bank. The local dominant species (such as Lespedeza davurica, Artemisia gmelinii, Bothriochloa ischaemun and Stipa bungeana) of the later succession stages also existed at densities varying from 17 to 1, 383 seeds m(-2). The combination of soil seed bank characteristics, reproductive traits of the species, the specific landscape conditions indicates that the potential to restoring the abandoned croplands in the hilly-gullied Loess Plateau via natural re-vegetation could be substantial.

[Prediction and mapping of potential vegetation distribution in Yanhe River catchment in hilly area of Loess Plateau].

The prediction and mapping of potential vegetation distribution is of instructive to the ecological restoration planning. By using generalized additive model (GAM) and in combining with GIS spatial analyst and environmental stratification sampling techniques, a distribution model for 24 dominant species in Yanhe River catchment was developed, and, based on the interspecific relationships in plant communities and the distribution probability, the spatial distribution of plant species was calculated, and the distribution of 37 plant communities and of the potential vegetation in Yanhe River catchment was predicted. The results showed that there were no significant differences between predictive values and actual data, and the predictive spatial distribution of vegetation could actually reflect the distribution of potential vegetation in Yanhe River catchment, suggesting that the established model had good ability for the vegetation distribution prediction, which was of significance to the goal-setting and planning of vegetation restoration.