Choroid plexus and its relations with age-related diseases.

The choroid plexus is composed of epithelial cells situated on the basal layer. The tight junctions between adjacent choroid plexus epithelial cells establish the blood-cerebrospinal fluid barrier. This barrier, in conjunction with the blood-brain barrier, is crucial for the homeostasis of the brain microenvironment. The choroid plexus epithelium secretes cerebrospinal fluid, growth factors, neuropeptides, and lipids into the ventricles and also serves as a gateway for immune cells to enter the brain. The pathophysiology of aging and neurodegenerative diseases remains largely enigmatic, with an increasing body of research linking the choroid plexus to the etiology of these age-related disorders. In this review, we summarize the known relationship between the choroid plexus epithelium and age-related diseases, aiming to provide new therapeutic clues for these disorders.

FGF19 protects skeletal muscle against obesity-induced muscle atrophy, metabolic derangement and abnormal irisin levels via the AMPK/SIRT-1/PGC-α pathway.

Obesity is associated with biological dysfunction in skeletal muscle. As a condition of obesity accompanied by muscle mass loss and physical dysfunction, sarcopenic obesity (SO) has become a novel public health problem. Human fibroblast growth factor 19 (FGF19) plays a therapeutic role in metabolic diseases. However, the protective effects of FGF19 on skeletal muscle in obesity and SO are still not completely understood. Our results showed that FGF19 administration improved muscle loss and grip strength in young and aged mice fed a high-fat diet (HFD). Increases in muscle atrophy markers (FOXO-3, Atrogin-1, MuRF-1) were abrogated by FGF19 in palmitic acid (PA)-treated C2C12 myotubes and in the skeletal muscle of HFD-fed mice. FGF19 not only reduced HFD-induced body weight gain, excessive lipid accumulation and hyperlipidaemia but also promoted energy expenditure (PGC-1α, UCP-1, PPAR-γ) in brown adipose tissue (BAT). FGF19 treatment restored PA- and HFD-induced hyperglycaemia, impaired glucose tolerance and insulin resistance (IRS-1, GLUT-4) and mitigated the PA- and HFD-induced decrease in FNDC-5/irisin expression. However, these beneficial effects of FGF19 on skeletal muscle were abolished by inhibiting AMPK, SIRT-1 and PGC-1α expression. Taken together, this study suggests that FGF19 protects skeletal muscle against obesity-induced muscle atrophy, metabolic derangement and abnormal irisin secretion partially through the AMPK/SIRT-1/PGC-α signalling pathway, which might be a potential therapeutic target for obesity and SO.

Effect of sarcolipin-mediated cell transdifferentiation in sarcopenia-associated skeletal muscle fibrosis.

Fibrosis is a key pathological event during muscle aging that accelerates the development of sarcopenia. We show that sarcolipin (SLN) is highly expressed during aging, promotes intracellular calcium overload and participates in impaired myogenic differentiation. d-Galactose (D-gal) was used to induce senescence in C2C12 myoblasts. Conventional AAV-mediated SLN knockdown cells were used to study the role of SLN in muscle physiology and pathophysiology. C2C12 cells were treated with D-gal, which promoted fibrosis and SLN upregulation. The expression of TGF-ß1 and α-SMA, which participate in myogenic transdifferentiation, were also elevated. C2C12 cells with reduced sarcolipin expression produced decreased amounts of collagen. Our study identified an unrecognized role of SLN in regulating myogenic transdifferentiation during aging-associated skeletal muscle cell fibrosis. Targeting SLN may be a novel therapeutic strategy to relieve sarcopenia-associated muscle fibrosis.

[Effects of Water-salt Environment on Freshwater Wetland Soil C, N, and P Ecological Stoichiometric Characteristics in the Yellow River Estuary Wetland].

Carbon (C), nitrogen (N), and phosphorus (P) are important nutrients, and their ecological stoichiometric characteristics can reflect the quality and fertility capacity of soil, which is critical to understanding the stable mechanisms of estuarine wetland ecosystems. Under global changes, the increase in salinity and flooding caused by sea level rise will lead to changes in biogeochemical processes in estuarine wetlands, which is expected to affect the ecological stoichiometric characteristics of soil C, N, and P and ultimately interfere with the stability of wetland ecosystems. However, it remains unclear how the C, N, and P ecological stoichiometric characteristics respond to the water-salt environment in estuarine wetlands. We differentiated changes in the C, N, and P ecological stoichiometric characteristics through an ex-situ culture experiment for 23 months in the Yellow River Estuary Wetland. The five sites with distinct tidal hydrology were selected to manipulate translocation of soil cores from the freshwater marsh to high-, middle-, and low-tidal flats in June 2019. The results showed that soil water content (SWC); electrical conductivity (EC); and C, N, and P ecological stoichiometric characteristics of freshwater marsh soil significantly changed after translocation for 23 months. SWC decreased on the high- and middle-tidal flats (P<0.05) and increased on the low-tidal flat (P<0.05). EC increased to different degrees on all three tidal flats (P<0.05). Soil total organic carbon (TOC) and total nitrogen (TN) were significantly lower on the high-tidal flat (P<0.05), whereas total phosphorus (TP) was significantly lower on the middle- and high-tidal flats (P<0.05). C:N was decreased on the high- and middle-tidal flats (P<0.05); C:P and N:P were lower on the high-tidal flat; and all C, N, and P ecological stoichiometric characteristics showed no change on the low-tidal flat (P>0.05). Pearson's analysis showed that the ecological stoichiometric characteristics of C, N, and P were related to some properties of soil over the culture sites. The PLS-SEM model showed that the water-salt environment had different effects on soil C:N, C:P, and N:P through the main pathways of negative effects on soil TOC and TP. The results suggest that sea level rise may impact the C, N, and P ecological stoichiometric characteristics in freshwater marsh soil, resulting in some possible changes in the nutrient cycles of estuarine wetlands.

The causality between gut microbiome and liver cirrhosis: a bi-directional two-sample Mendelian randomization analysis.

Background and aim: Previous studies have reported an association between gut microbiota and cirrhosis. However, the causality between intestinal flora and liver cirrhosis still remains unclear. In this study, bi-directional Mendelian randomization (MR) analysis was used to ascertain the potential causal effect between gut microbes and cirrhosis. Methods: Large-scale Genome Wide Association Study (GWAS) data of cirrhosis and gut microbes were obtained from FinnGen, Mibiogen consortium, and a GWAS meta-analysis of Alcoholic cirrhosis (ALC). Two-sample MR was performed to determine the causal relationship between gut microbiota and cirrhosis. Furthermore, a bi-directional MR analysis was employed to examine the direction of the causal relations. Result: In MR analysis, we found that 21 gut microbiotas were potentially associated with cirrhosis. In reverse MR analysis, 11 gut microbiotas displayed potentially associations between genetic liability in the gut microbiome and cirrhosis. We found that the family Lachnospiraceae (OR: 1.59, 95% CI:1.10-2.29) might be harmful in cirrhotic conditions (ICD-10: K74). Furthermore, the genus Erysipelatoclostridium might be a protective factor for cirrhosis (OR:0.55, 95% CI:0.34-0.88) and PBC (OR:0.68, 95% CI:0.52-0.89). Combining the results from the MR analysis and reverse MR analysis, we firstly identified the Genus Butyricicoccus had a bi-directional causal effect on PBC (Forward: OR: 0.37, 95% CI:0.15-0.93; Reverse: OR: 1.03, 95% CI:1.00-1.05). Conclusion: We found a new potential causal effect between cirrhosis and intestinal flora and provided new insights into the role of gut microbiota in the pathological progression of liver cirrhosis.

Artificial intelligence improves accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor for adult refractometry.

AIM: To evaluate the accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor (hICA) with artificial intelligence (AI) by comparing its refraction measurements to those recorded using hICA and a clinical table-mounted automatic refractor (TAR). METHODS: A cross-sectional study using three optometers, including hICA with or without AI and TAR, for refractometry of adults (aged 19-49 years old) with no signs of ocular disease or trauma in the absence of cycloplegia. Right and left eye refraction data were recorded, including the spherical equivalent (SE), diopter of spherical power (DS), diopter of cylindrical power (DC) decomposed into vectors J0 and J45, and measurement times. To avoid analytical difficulties associated with the interdependence of observations between eyes from the same individual, the Generalized Estimation Equation was used to compare the SE, DS, J0 and J45 measurements, and the times thereof, among the different groups. The intraclass correlation coefficient (ICC) and Spearman's rank correlation coefficient were used to evaluate correlations among the measurements recorded by the three different instruments. Bland-Altman were used to analyze the precision of the equipment by the agreement. RESULTS: A total of 70 patients (140 eyes; mean age: 31.37y; range: 19-49y) were assessed using refractometry. In a brightly lit environment, there was no significant difference between the mean SE recorded using TAR and that recorded using hICA with AI or without AI (both P>0.05). In an intense-light environment, hICA equipped with AI showed a better detection rate than without AI. Light intensity had a greater effect on dioptric measurements recorded using hICA without AI (P<0.001) than on those recorded using the one equipped with AI (P<0.05). Measurement times varied significantly between the different light intensities and instruments (P<0.05). CONCLUSION: For the normal human eyes, AI may improve the accuracy, efficiency, and reliability of measurements recorded using hICA in various light environments.

Porous and Ultra-Flexible Crosslinked MXene/Polyimide Composites for Multifunctional Electromagnetic Interference Shielding.

Lightweight, ultra-flexible, and robust crosslinked transition metal carbide (Ti3C2 MXene) coated polyimide (PI) (C-MXene@PI) porous composites are manufactured via a scalable dip-coating followed by chemical crosslinking approach. In addition to the hydrophobicity, anti-oxidation and extreme-temperature stability, efficient utilization of the intrinsic conductivity of MXene, the interfacial polarization between MXene and PI, and the micrometer-sized pores of the composite foams are achieved. Consequently, the composites show a satisfactory X-band electromagnetic interference (EMI) shielding effectiveness of 22.5 to 62.5 dB at a density of 28.7 to 48.7 mg cm-3, leading to an excellent surface-specific SE of 21,317 dB cm2 g-1. Moreover, the composite foams exhibit excellent electrothermal performance as flexible heaters in terms of a prominent, rapid reproducible, and stable electrothermal effect at low voltages and superior heat performance and more uniform heat distribution compared with the commercial heaters composed of alloy plates. Furthermore, the composite foams are well attached on a human body to check their electromechanical sensing performance, demonstrating the sensitive and reliable detection of human motions as wearable sensors. The excellent EMI shielding performance and multifunctionalities, along with the facile and easy-to-scalable manufacturing techniques, imply promising perspectives of the porous C-MXene@PI composites in next-generation flexible electronics, aerospace, and smart devices.

The Whole-transcriptome Landscape of Diabetes-related Sarcopenia Reveals the Specific Function of Novel lncRNA Gm20743.

While the exact mechanism remains unclear, type 2 diabetes mellitus increases the risk of sarcopenia which is characterized by decreased muscle mass, strength, and function. Whole-transcriptome RNA sequencing and informatics were performed on the diabetes-induced sarcopenia model of db/db mice. To determine the specific function of lncRNA Gm20743, the detection of Mito-Sox, reactive oxygen species, Ethynyl-2'-deoxyuridine, and myosin heavy chain was performed in overexpressed and knockdown-Gm20743 C2C12 cells. RNA-seq data and informatics revealed the key lncRNA-mRNA interactions and indicated a potential regulatory role of lncRNAs. We characterized three core candidate lncRNAs Gm20743, Gm35438, 1700047G03Rik, and their potential function. Furthermore, the results suggested lncRNA Gm20743 may be involved in regulating mitochondrial function, oxidative stress, cell proliferation, and myotube differentiation in skeletal muscle cells. These findings significantly improve our understanding of lncRNAs that may mediate muscle mass, strength, and function in diabetes and represent potential therapeutic targets for diabetes-induced sarcopenia.

Comparison of delta-shaped anastomosis and Billroth I reconstruction after laparoscopic distal gastrectomy for gastric cancer.

BACKGROUND: This study intends to compare the short-term effects and long-term survival of gastric cancer patients who underwent delta-shaped anastomosis (DA) and Billroth I reconstructions after laparoscopic distal gastrectomy. METHODS: We retrospectively collected data from 257 patients with gastric cancer who underwent laparoscopic distal gastrectomy between January 2013 and December 2017. Patients were classified into 2 groups according to the reconstruction method used: the DA group (n=91) and the Billroth I group (n=166). The clinical data, short-term efficacy, and long-term results were compared between the 2 groups. RESULTS: The operation time (P<0.001) and the post-operative length of hospital stay (P<0.001) were shorter in the DA group than in the Billroth I group. The time to the first oral intake of a soft diet after surgery was earlier in the DA group than in the Billroth I group (P=0.014). Kaplan-Meier (log-rank test) analysis showed no significant difference in the 5-year survival rates between the 2 groups for patients at the same pathological stage. Multivariate analysis showed that abnormal carcinoembryonic antigen (CEA) (P=0.006), chemotherapy (P<0.001), T stage (P<0.001), and N stage (P<0.001) were independent prognostic factors for survival. CONCLUSIONS: DA and Billroth I are feasible and safe reconstruction methods of the digestive tract after gastric cancer. DA is the recommended reconstruction method for laparoscopic distal gastrectomy.

MICU3 regulates mitochondrial Ca2+-dependent antioxidant response in skeletal muscle aging.

Age-related loss of skeletal muscle mass and function, termed sarcopenia, could impair the quality of life in the elderly. The mechanisms involved in skeletal muscle aging are intricate and largely unknown. However, more and more evidence demonstrated that mitochondrial dysfunction and apoptosis also play an important role in skeletal muscle aging. Recent studies have shown that mitochondrial calcium uniporter (MCU)-mediated mitochondrial calcium affects skeletal muscle mass and function by affecting mitochondrial function. During aging, we observed downregulated expression of mitochondrial calcium uptake family member3 (MICU3) in skeletal muscle, a regulator of MCU, which resulted in a significant reduction in mitochondrial calcium uptake. However, the role of MICU3 in skeletal muscle aging remains poorly understood. Therefore, we investigated the effect of MICU3 on the skeletal muscle of aged mice and senescent C2C12 cells induced by D-gal. Downregulation of MICU3 was associated with decreased myogenesis but increased oxidative stress and apoptosis. Reconstitution of MICU3 enhanced antioxidants, prevented the accumulation of mitochondrial ROS, decreased apoptosis, and increased myogenesis. These findings indicate that MICU3 might promote mitochondrial Ca2+ homeostasis and function, attenuate oxidative stress and apoptosis, and restore skeletal muscle mass and function. Therefore, MICU3 may be a potential therapeutic target in skeletal muscle aging.

[Vegetative reproduction characteristics of Leymus chinensis in heterogeneous habitats in Songnen Plain, China]. / æ¾å«©å¹³åŽŸå¼‚è´¨ç”Ÿå¢ƒç¾Šè‰ç§ç¾¤è¥å »ç¹æ®–ç‰¹å¾.

The perennial clonal grasses rely mainly on vegetative reproduction to achieve continuous regeneration. Buds and juvenile tillers formed by buds are potential populations for vegetative reproduction. We compared the composition and size of potential population of Leymus chinensis in the enclosure meadow, long-term mowing meadow, enclosing sand-covered meadow, and forest-grassland, with excavation sampling by unit area and using vegetative reproduction generations to classify the age of tillers, rhizomes and various types of buds and juvenile tillers. The results showed that at the end of the growing season, potential population of L. chinensis was composed of rhizome buds and buds of tiller growing upwards at different ages, as well as juvenile tillers on the tillers and rhizomes. Across the four habitats, the potential population of tillers of L. chinensis was composed of 3-4 age classes, and the rhizomes' potential population consisted of four age classes, of which the potential population formed by rhizomes accounted for 68.3% of the total potential population. The potential population produced by 1st age class tillers and rhizomes accounted for 60.2% of the total, which was the main part of the potential population composition and the main source of population renewal. The potential population of tillers was the most abundant in long-term mowing meadow. The potential population of rhizomes was the most abundant in enclosing sand-covered meadow. The vegetative fertility of tillers and rhizomes was the highest in young age. The vegetative fertility of rhizomes was 10.0 times as that of tillers, which dominated the vegetative reproduction of L. chinensis. The potential population composition of L. chinensis varied greatly across different habitats, reflecting the divergent adaptation to habitat variation.

Type 2 diabetes-induced overactivation of P300 contributes to skeletal muscle atrophy by inhibiting autophagic flux.

AIMS: Although autophagy impairment is a well-established cause of muscle atrophy and P300 has recently been identified as an important regulator of autophagy, the effects of P300 on autophagy and muscle atrophy in type 2 diabetes (T2D) remain unexplored. We aimed at characterizing the role of P300 in diabetic muscle and its underlying mechanism. MAIN METHODS: Protein levels of phosphorylated P300, total P300, acetylated histone H3, LC3, p62 and myosin heavy chain, and mRNA levels of Atrogin-1 and MuRF1 were analyzed in palmitic acid (PA)-treated myotubes and db/db mice. Autophagic flux was assessed using transmission electron microscopy, immunofluorescence and mRFP-GFP-LC3 lentivirus transfection in cells. Muscle weight, blood glucose and grip strength were measured in mice. Hematoxylin and eosin (H&E) staining was performed to determine changes in muscle fiber size. To investigate the effects of P300 on autophagy and myofiber remodeling, a P300 specific inhibitor, c646, was utilized. 3-Methyladenine (3-MA) was utilized to inhibit autophagosomes formation, and chloroquine (CQ) was used to block autophagic flux. KEY FINDINGS: Phosphorylation of P300 in response to PA enhanced its activity and subsequently suppressed autophagic flux, leading to atrophy-related morphological and molecular changes in myotubes. Inhibition of P300 reestablished autophagic flux and ameliorated PA-induced myotubes atrophy. However, this effect was largely abolished by co-treatment with the autophagy inhibitor CQ. In vivo results demonstrated that inhibition of P300 partially rescued muscle wasting in db/db mice, accompanied with autophagy reactivation. SIGNIFICANCE: The findings revealed that T2D-induced overactivation of P300 contributes to muscle atrophy by blocking autophagic flux.

Effect of aridification on the replacement of zonic species, Stipa baicalensis Roshev., by azonic species, Leymus chinensis Tzvel., in the steppe of China.

The perennial grass Stipa baicalensis is the zonic species in the steppe of China, but is currently being replaced by the azonic species of Leymus chinensis. In this area, aridification is on the increase; therefore, we hypothesize that water competition plays a significant role in this succession. The limit of osmotic adjustment in S. baicalensis (13.94%-16.30% PEG) was much lower than that in L. chinensis (17.20%-24.50% PEG) in response to drought. The synoptic causal model accounted for most of the variation in the process of physiological regulation as indicated by the small residual effect (0.121-0.161). These results demonstrated that the two species dealt with drought in different ways. Stomata of L. chinensis acted more directly on transpiration, and the advantage in water competition resulted from the powerful stomatal control. On the other hand, S. baicalensis was more easily affected by non-stomatal limitation which was physiologically inactive in response to drought. Results supported the hypothesis above. S. baicalensis was more susceptible to the damage of aridification and was less competitive to water than L. chinensis.

Phenotypic plasticity of life history characteristics: quantitative analysis of delayed reproduction of green foxtail (Setaria viridis) in the Songnen Plain of China.

Green foxtail (Setaria viridis L.) is a common weed species in temperate regions. Research on the effect of delayed reproduction on the phenotypic plasticity and regularity of the vegetative and reproductive growth is of vital significance for understanding population regulation and control of the weed in the growing season. Green foxtail seeds were sown every 10 days from 25 June to 24 August of 2004. The growth and production metrics were measured via harvesting tufts and statistical analysis was carried out. The results showed that the reproductive tillers, seed number, seed biomass and one thousand-seed weight of plants at the first sowing (25 June) approximately increased 28.8, 7 827.0, 1 104.0 and 12.3 times compared with that at the last sowing (24 August), respectively. Total tillers, reproductive tillers and height increased linearly as the reproductive period delayed, however, biomass increased exponentially. Quadratic equations best explained the relationships between the delayed reproductive period and seed number, inflorescence length, one thousand-seed weight, seed biomass. Based on the quantity and quality of seed production, weeding young seedlings emerging before July can be the most effective weed-control strategy in the Songnen Plain.

Gene cloning, sequencing, expression and biological activity of giant panda (Ailuropoda melanoleuca) interferon-alpha.

The giant panda (Ailuropoda melanoleuca) is an endangered species and indigenous to China. In mammals, multiple subtypes of interferon-alpha (IFN-alpha) exist, most of which possess antiviral activity. Little is known about giant panda IFN-alpha genes and the role they may play in giant panda immunological responses to viruses. We have cloned genes encoding 12 giant panda IFN-alpha (AmIFN-alpha or AmIFNA) subtypes that share from 90 to 99% amino acid sequence identity. AmIFN-alpha12 has one additional amino acid at position 57, which is not present in other subtypes. Sequence identity of the AmIFN-alpha proteins encoded by the 12 genes compared to human IFN-alpha2 is approximately 58%. Unlike most of the human subtypes, each of the 12 giant panda IFN sequences has an N-glycosylation recognition site. Expression of all 12 AmIFN-alpha subtypes in 293 cells was confirmed by SDS-PAGE and Western blotting analysis. The antiviral activity and antiproliferative activity of each AmIFN-alpha subtype produced in transiently transfected 293 cell cultures were tested in vitro. All AmIFN-alpha subtypes were found to be stable at pH 2 or 65 degrees C and to exhibit antiviral activity. Some IFN subtypes (AmIFN-alpha8 and AmIFN-alpha4) showed higher biological activity levels than others, whereas AmIFN-alpha11 exhibited lower activity. AmIFN-alpha had various antiproliferative activities to different target cells. To B16 cells, AmIFN-alpha3, AmIFN-alpha4, AmIFN-alpha8 had the highest activities, while to K562 cells, AmIFN-alpha3, AmIFN-alpha7, AmIFN-alpha10 had the highest activities. The various IFN-alpha subtypes displayed a good correlation between their antiviral and antiproliferative potencies.

[Effect of red and blue spectrum on photosynthesis physiological characteristics of two ecotypes of Leymus chinensis].

Photosynthesis physiological characteristics of two ecotypes of Leymus chinensis were studied under different red and blue light excitation by LED red and blue lamp-house. Photosynthesis did not carry on under red and blue light of 50 micromol x m(-2) x s(-1). When red and blue light intensity was increased, photosynthesis rate, stoma limit value and transpiration rate of the two ecotypes of Leymus chinensis were all increased. But photosynthesis rate stopped increasing under red and blue light of 1 150 micromol x m(-2) x s(-1) for grey-green ecotype Leymus chinensis and of 907 micromol x m(-2) x s(-1) for yellow-green ecotype Leymus chinensis, which is known as light saturation. And the effect of blue light on photosynthesis became weaker than red light under higher light intensity. Increasing light intensity can promote plant photosynthesis rate in the range of low light intensity. But when light intensity reaches light saturation, photosynthesis rate does not increases but decreases. Because though light quantum numbers is increasing, the numbers of coloring mater does not change and is saturated. On the other hand, when the light intensity is of light saturation, the stoma limit value was increased and the transpiration rate was decreased in order to reduce water waste. When light intensity reaches the value that plant can bear, the plant will automatically close stoma in order to decrease transpiration and to save water. Plant balances every physiological index and makes sure that physiology damage is the least and production is the greatest. Although grey-green ecotype Leymus chinensis has lower stoma limit and higher water waste, it also has higher photosynthesis rate than yellow-green ecotype Leymus chinensis. And the photosynthesis capability and physiology adaptation of grey-green ecotype Leymus chinensis is greater than that of yellow-green ecotype Leymus chinensis.

[Module growth and biomass allocation of Chloris virgate clone at different growth stages in Songnen Plain, China]. / æ¾å«©å¹³åŽŸä¸åŒç”Ÿè‚²æœŸè™Žå°¾è‰æ— æ€§ç³»æž„ä»¶ç”Ÿé•¿ä¸Žç”Ÿç‰©é‡åˆ†é .

The growth characteristic and strategies of Chloris virgate at different growth stages were examined in Songnen Plain by analyzing the quantitative characters and biomass allocation of aboveground and belowground parts at shooting and ripening stages in C. virgate population, with a large amount of sampling. The results showed that height, total root length, total root surface area, root volume, aboveground biomass, belowground biomass, and total biomass were significantly different between the two growth stages. There was power allometric relationship between total biomass and biomass allocation of aboveground and belowground, respectively. At shooting stage, there was a significant linear isometric growth between the total biomass and the number of ramets, total root length, total root surface area and root volume, but there was a power allometric growth at ripening stage. C. virgate clone showed different growth strategies under different growth stages, with a priority expansion strategy of clonal outer space at shooting stage and a complementary and expansive strategy in the inner and outer space of the clones at ripening stage.

[Age structure and growth characteristics of Juglans cathayensis seedling populations at different slope aspects in Wild Walnut Natural Conservation Area of Xinjiang, China]. / æ–°ç–†é‡Žæ ¸æ¡ƒè‡ªç„¶ä¿æŠ¤åŒºä¸åŒå¡å‘é‡Žæ ¸æ¡ƒå¹¼è‹—ç§ç¾¤å¹´é¾„ç»“æž„åŠç”Ÿé•¿ç‰¹å¾.

For grasping the composition and growth characteristics of seedling populations of Juglans cathayensis, a national grade 2 endangered plant, four 2-hm2 plots were set up at different slope aspects in Wild Walnut Natural Conservation Area of Xinjiang, China. Adjacent lattice method was used to survey J. cathayensis seedlings. The relationships between the number, basal diameter and plant height of J. cathayensis seedling populations were analyzed. The results showed that seedlings at 1st age were more abundant on sunny, semi-sunny, shady and semi-shady slopes. The number of seedlings was predominant at 1st-3rd age. Seedling populations at different slope aspects showed an expanding age structure. 5.7% of 1st age seedlings could survive to 4th age, and 1.7% could survive to 7th age. The number of J. cathayensis seedlings had a critical turning point at the 3rd age. The seedlings of J. cathayensis were considered as r-strategists in their lives. The basal diameter and plant height of seedlings were slow-growing before 3rd age and fast-growing after 3rd age. Average growth rate of basal diameter was 3.6 mm·a-1and decreased in the order of shady slope, sunny slope, semi-shady slope and semi-sunny slope. Average growth rate of plant height was 9.0 cm·a-1 and decreased in the order of sunny slope, semi-sunny slope, semi-shady slope and shady slope. Basal diameter and plant height of seedlings exponentially increased with the increase of age. The relationships between plant height and basal diameter showed power function. Growth rates of seedling traits could be reflected by the properties and parameters of functions.

[Distribution patterns of Juglans cathayensis populations at different slope aspects in Tianshan valley in Xinjiang, China]. / æ–°ç–†å¤©å±±å³¡è°·ä¸åŒå¡å‘é‡Žæ ¸æ¡ƒç§ç¾¤åˆ†å¸ƒæ ¼å±€.

Eight 4000 m2 plots were set up at eight sites distributed on sunny and shady slopes of four valleys, and adjacent lattice method was used to survey Juglans cathayensis populations. At different scales, aggregation intensity index such as variance/mean ration and deviation index (Cx), negative binomial parameter (K), clumping index (I), mean crowding index (m*), patchiness index (PAI) and aggregation index (Ca) were used to analyze distribution patterns of populations. With the increase of surveying scales, the distribution patterns changed from cluster to random. Populations presented a clustered distribution when the scale was 25 m2. Aggregation intensity had great differences among different plots, and the maximum one located on west shady slope and the minimum one did on south shady slope. However, populations presented a random distribution when the scale was 50-400 m2. When scale was 25 m2, saplings, young and mature trees showed a clustered distribution. Aggregation intensity of mature trees was the maximum one and that of saplings was the minimum one. When the scale was 200-400 m2, saplings, young and mature trees showed random distribution. The pattern size of J. cathayensis populations was 25 m2 and pattern intensity was 2.49-9.38 m2. The pattern intensity of young trees was the largest and that of mature trees was the least in population components. In a word, when sampling scale was close to population patch size, a reliable conclusion usually could be obtained by using adaptive determination method and multi-index comprehensive decision.