Current patterns of plant diversity and phylogenetic structure on the Kunlun Mountains.

Large-scale patterns of biodiversity and the underlying mechanisms that regulate these patterns are central topics in biogeography and macroecology. The Qinghai-Tibet Plateau serves as a natural laboratory for studying these issues. However, most previous studies have focused on the entire Qinghai-Tibet Plateau, leaving independent physical geographic subunits in the region less well understood. We studied the current plant diversity of the Kunlun Mountains, an independent physical geographic subunit located in northwestern China on the northern edge of the Qinghai-Tibet Plateau. We integrated measures of species distribution, geological history, and phylogeography, and analyzed the taxonomic richness, phylogenetic diversity, and community phylogenetic structure of the current plant diversity in the area. The distribution patterns of 1911 seed plants showed that species were distributed mainly in the eastern regions of the Kunlun Mountains. The taxonomic richness, phylogenetic diversity, and genera richness showed that the eastern regions of the Kunlun Mountains should be the priority area of biodiversity conservation, particularly the southeastern regions. The proportion of Chinese endemic species inhabiting the Kunlun Mountains and their floristic similarity may indicate that the current patterns of species diversity were favored via species colonization. The Hengduan Mountains, a biodiversity hotspot, is likely the largest source of species colonization of the Kunlun Mountains after the Quaternary. The net relatedness index indicated that 20 of the 28 communities examined were phylogenetically dispersed, while the remaining communities were phylogenetically clustered. The nearest taxon index indicated that 27 of the 28 communities were phylogenetically clustered. These results suggest that species colonization and habitat filtering may have contributed to the current plant diversity of the Kunlun Mountains via ecological and evolutionary processes, and habitat filtering may play an important role in this ecological process.

Multimode Gesture Recognition Algorithm Based on Convolutional Long Short-Term Memory Network.

Gesture recognition utilizes deep learning network model to automatically extract deep features of data; however, traditional machine learning algorithms rely on manual feature extraction and poor model generalization ability. In this paper, a multimodal gesture recognition algorithm based on convolutional long-term memory network is proposed. First, a convolutional neural network (CNN) is employed to automatically extract the deeply hidden features of multimodal gesture data. Then, a time series model is constructed using a long short-term memory (LSTM) network to learn the long-term dependence of multimodal gesture features on the time series. On this basis, the classification of multimodal gestures is realized by the SoftMax classifier. Finally, the method is experimented and evaluated on two dynamic gesture datasets, VIVA and NVGesture. Experimental results indicate that the accuracy rates of the proposed method on the VIVA and NVGesture datasets are 92.55% and 87.38%, respectively, and its recognition accuracy and convergence performance are better than those of other comparison algorithms.

Development of genomic microsatellite markers for Aconitum gymnandrum (Ranunculaceae) by next generation sequencing (NGS).

Mating plays key roles in the demographic and genetic dynamics of populations. Estimates of mating portfolios and system based on progeny array (PA) method required highly polymorphic genetic markers, of which microsatellite is a good choice. In this study, we reported 19 polymorphic microsatellite loci for Aconitum gymnandrum. The number of alleles per locus ranged from 2 to 12. Observed and expected heterozygosity ranged from 0.000 to 1.000 and from 0.219 to 0.842, respectively. Seven loci showed significant deviation from Hardy-Weinberg equilibrium. These markers will provide a useful tool for pollination ecology and population genetic studies of A. gymnandrum in Qinghai-Tibet plateau.

[Relation between species distribution of plant community and soil factors under grazing in alpine meadow]. / æ”¾ç‰§ä½œç”¨ä¸‹é«˜å¯’è‰ç”¸ç¾¤è½ç‰©ç§åˆ†å¸ƒä¸ŽåœŸå£¤å› å­çš„å ³ç³».

The research selected the alpine meadow located in the northeastern margin of the Qinghai-Tibet Plateau to study the changes of vegetation community and soil properties under different grazing intensities, as well as the quantitative relation between the distribution patterns of plant species and the physical and chemical properties of soil. The results showed that the grazing caused the differentiation of the initial vegetation community with the dominant plants, Elymus nutans and Stipa grandis. In the plots with high and low grazing intensities, the dominant plants had changed to Kobresia humilis and Melissitus ruthenica, and E. nutans and Poa crymophila, respectively. With the increase of grazing intensity, the plant richness, importance value and biomass were significantly decreased. The sequence of plant species importance value in each plot against grazing intensity could be fitted by a logarithmic model. The number of required plant species was reduced while the importance value of the remaining plant species accounted for 50% of the importance value in the whole vegetation community. The available P, available K, soil compaction, soil water content, stable infiltration rate and large aggregate index were significantly changed with grazing intensity, however, the changes were different. The CCA ordination showed that the soil compaction was the key factor affecting the distribution pattern of the plant species under grazing. The variance decomposition indicated that the soil factors together explained 30.5% of the distribution of the plant species, in particular the soil physical properties alone explained 22.8% of the distribution of the plant species, which had the highest rate of contribution to the plant species distribution. The soil physical properties affected the distribution pattern of plant species on grazed alpine meadow.

[Response of soil ciliate to diammonium phosphate addition in alpine meadow of southern Gansu, Northwest China]. / ç”˜å—é«˜å¯’è‰ç”¸åœŸå£¤çº¤æ¯›è™«å¯¹ç£·é ¸æ°¢äºŒé“µæ·»åŠ çš„å“åº”.

In typical alpine meadow of southern Gansu Province, five sampling sites by fertilizer diammonium phosphate (DAP) addition ranging from 0 g·m-2 to 120 g·m-2 were set in order to examine the response of soil ciliate communities to different concentrations of DAP. An investigation on the abundance and species richness of soil ciliates was carried out by non-flooded Petri dish, observation in vivo and three-level ten-fold dilution methods. Soil physicochemical factors including soil water content, pH value, contents of soil total nitrogen, total phosphorus and organic carbon at different sites were also measured. It was found that there was a total of 129 species belonging to 9 classes, 17 orders, 31 families and 46 genera. Lower species richness and diversity but higher ciliate abundance were observed in the soils with higher concentrations of DAP compared with the control. The dominant group Haptorida was substituted by Colpodida from the control to the soils with the increase of fertilizer application. The results of redundancy analysis indicated that the gradient changes of total phosphorus, soil temperature and water content were the main driving factors for the change of soil ciliate community distribution.

Niche and Neutral Processes Together Determine Diversity Loss in Response to Fertilization in an Alpine Meadow Community.

Fertilization via nutrient deposition and agricultural inputs is one of the most important factors driving decreases in plant diversity. However, we still do not fully understand which processes (niche process or neutral process) are more important in leading to decreases in plant diversity caused by fertilization. A hypothesis-based approach was used to test the relative importance of niche versus neutral processes along a fertilization gradient in an alpine meadow community on the eastern Tibetan plateau, China. Niche overlap values were calculated for species biomass, and the null model was used to generate the values of niche overlap expected at random. A linear regression modeling was used to evaluate the relationship between functional traits (specific leaf area, leaf dry matter content, and leaf total nitrogen concentration) and species relative abundance. Our results demonstrated that observed niche overlap for species biomass was significantly higher than expected at lower fertilization gradients. Moreover, we also found a significantly negative correlation between species relative abundance and specific leaf area and leaf dry matter content, but a significantly positive correlation between relative abundance and leaf nitrogen concentration at lower fertilization gradients. However, these relationships were not significant at higher fertilization gradients. We concluded that community assembly is dynamic progression along the environmental gradients, and niche and neutral processes may together determine species diversity loss in response to fertilization.

Plant Functional Diversity Can Be Independent of Species Diversity: Observations Based on the Impact of 4-Yrs of Nitrogen and Phosphorus Additions in an Alpine Meadow.

Past studies have widely documented the decrease in species diversity in response to addition of nutrients, however functional diversity is often independent from species diversity. In this study, we conducted a field experiment to examine the effect of nitrogen and phosphorus fertilization ((NH4)2 HPO4) at 0, 15, 30 and 60 g m-2 yr-1 (F0, F15, F30 and F60) after 4 years of continuous fertilization on functional diversity and species diversity, and its relationship with productivity in an alpine meadow community on the Tibetan Plateau. To this purpose, three community-weighted mean trait values (specific leaf area, SLA; mature plant height, MPH; and seed size, SS) for 30 common species in each fertilization level were determined; three components of functional diversity (functional richness, FRic; functional evenness, FEve; and Rao's index of quadratic entropy, FRao) were quantified. Our results showed that: (i) species diversity sharply decreased, but functional diversity remained stable with fertilization; (ii) community-weighted mean traits (SLA and MPH) had a significant increase along the fertilization level; (iii) aboveground biomass was not correlated with functional diversity, but it was significantly correlated with species diversity and MPH. Our results suggest that decreases in species diversity due to fertilization do not result in corresponding changes in functional diversity. Functional identity of species may be more important than functional diversity in influencing aboveground productivity in this alpine meadow community, and our results also support the mass ratio hypothesis; that is, the traits of the dominant species influenced the community biomass production.

Intraspecific competition and light effect on reproduction of Ligularia virgaurea, an invasive native alpine grassland clonal herb.

The relationship between sexual reproduction and clonal growth in clonal plants often shows up at the ramet level. However, only a few studies focus on the relationship at the genet level, which could finally account for evolution. The sexual reproduction and clonal growth of Ligularia virgaurea, a perennial herb widely distributed in the alpine grasslands of the Qinghai-Tibetan Plateau of China, were studied under different competition intensities and light conditions at the genet level through a potted experiment. The results showed that: (1) sexual reproduction did not depend on density or light, and increasing clonal growth with decreasing density and increasing light intensity indicated that intraspecific competition and light intensity may affect the clonal life history of L. virgaurea; (2) both sexual reproduction and clonal growth show a positive linear relationship with genet size under different densities and light conditions; (3) a threshold size is required for sexual reproduction and no evidence of a threshold size for clonal growth under different densities and light conditions; (4) light level affected the allocation of total biomass to clonal and sexual structures, with less allocation to clonal structures and more allocation to sexual structures in full sunlight than in shade; (5) light determined the onset of sexual reproduction, and the genets in the shade required a smaller threshold size for sexual reproduction to occur than the plants in full sunlight; and (6) no evidence was found of trade-offs between clonal growth and sexual reproduction under different densities and light conditions at the genet level, and the positive correlation between two reproductive modes indicated that these are two integrated processes. Clonal growth in this species may be viewed as a growth strategy that tends to maximize genet fitness.

[Effects of UV-B radiation on the growth and reproduction of Vicia angustifolia].

A simulation experiment with supplementation and exclusion of solar ultraviolet-B (UV-B) radiation was conducted to study the effects of enhanced and near ambient UV-B radiation on the growth and reproduction of alpine annual pasture Vicia angustifolia on Qinghai-Tibet Plateau. Enhanced UV-B decreased the plant height and biomass, biomass allocation to fruit, flower number, and 100-seed mass significantly, delayed flowering stage, increased the concentration degree of flowering and success rate of reproduction, but had little effect on seed yield. Near ambient UV-B radiation made the plant height increased after an initial decrease, decreased biomass allocation to fruit and 100-seed mass, but little affected flowering duration, flower number, and seed yield. Both enhanced and near ambient UV-B radiation could inhibit the growth and production of V. angustifolia, and the effect of enhanced UV-B radiation was even larger.

Effects of positive interactions, size symmetry of competition and abiotic stress on self-thinning in simulated plant populations.

BACKGROUND AND AIMS: Competition drives self-thinning (density-dependent mortality) in crowded plant populations. Facilitative interactions have been shown to affect many processes in plant populations and communities, but their effects on self-thinning trajectories have not been investigated. METHODS: Using an individual-based 'zone-of-influence' model, we studied the potential effects of the size symmetry of competition, abiotic stress and facilitation on self-thinning trajectories in plant monocultures. In the model, abiotic stress reduced the growth of all individuals and facilitation ameliorated the effects of stress on interacting individuals. KEY RESULTS: Abiotic stress made the log biomass-log density relationship during self-thinning steeper, but this effect was reduced by positive interactions among individuals. Size-asymmetric competition also influenced the self-thinning slope. CONCLUSIONS: Although competition drives self-thinning, its course can be affected by abiotic stress, facilitation and competitive symmetry.

The effect of flower position on variation and covariation in floral traits in a wild hermaphrodite plant.

BACKGROUND: Floral traits within plants can vary with flower position or flowering time. Within an inflorescence, sexual allocation of early produced basal flowers is often female-biased while later produced distal flowers are male-biased. Such temporal adjustment of floral resource has been considered one of the potential advantages of modularity (regarding a flower as a module) in hermaphrodites. However, flowers are under constraints of independent evolution of a given trait. To understand flower diversification within inflorescences, here we examine variation and covariation in floral traits within racemes at the individual and the maternal family level respectively in an alpine herb Aconitum gymnandrum (Ranunculaceae). RESULTS: We found that floral traits varied significantly with flower position and among families, and position effects were family-specific. Most of the variance of floral traits was among individuals rather than among flowers within individuals or among families. Significant phenotypic correlations between traits were not affected by position, indicating trait integration under shared developmental regulation. In contrast, positive family-mean correlations in floral traits declined gradually from basal to distal flowers (nine significant correlations among floral traits in basal flowers and only three in distal flowers), showing position-specificity. Therefore, the pattern and magnitude of genetic correlations decreased with flower position. CONCLUSIONS: This finding on covariation pattern in floral reproductive structures within racemes has not been revealed before, providing insights into temporal variation and position effects in floral traits within plants and the potential advantages of modularity in hermaphrodites.

[Effects of compensation capacity and palatability on the dominance of plant species in grazing community].

With simulated mowing experiment and field survey, the compensation capacity and dominance shift of nine alpine plant species in grazing community were studied. The results showed that for most test species, there existed definite correlations between their compensation capacity and palatability. The species with better palatability, i.e., Astragalus polycladus, Medicago rythenica, Kobresia humilis, and Polygonum viviparvum, had higher compensation capacity, with their compensation index being 1.013, 0.907, 0.849, and 0.802, respectively, followed by Elymus nutans, with its compensation index being 0.668, while the species with poorer palatability, i.e., Taraxacum tibetanum, Swertis bimaculata, and Ajania tenuifolia had lower compensation capacity, with their compensation index being 0.649, 0.587, and 0.553, respectively. Festuca sinensis was more palatable but had the lowest compensation index (0.473). The nine species had three types of dominance shift, i.e., decreasing, increasing, and neutral. F. sinensis was of decreasing type, E. nutans, A. polycladus and P. viviparvum were of neutral, and the other five species were of increasing type. The compensation capacity and palatability of plant species in grazing community could explain their dominance shift to a certain extent.

[Effects of nutrient and light on seedlings morphological plasticity of four Saussurea species with different ecological breadth].

Taking four Saussurea species with different ecological breadth in the eastern Qinghai-Tibetan Plateau as test materials, their seedlings relative growth rate (RGR), root mass to shoot mass ratio (R/S), and specific leaf area (SLA) were determined under different nutrient and light treatments. The results showed that nutrient and light had significant effects on the seedlings RGR, R/S and SLA of the four Saussurea species, and there existed a certain interactive effect between nutrient and light. The plasticity of these morphological characteristics and their response patterns to the variation of nutrient and light conditions varied with species. Significant interactive effects (P < 0.001) between light, nutrient, and species were observed on the R/S and SLA of Saussurea. For the four Saussurea species, the mean phenotypic plasticity index of their seedlings was positively correlated with their ecological distribution, being the highest (0.71) for S. japonica, the best widespread species in the four species. The morphological plasticity of Saussurea species was positively related to their distribution ecological breadth.

Covariance of floral and vegetative traits in four species of Ranunculaceae: a comparison between specialized and generalized pollination systems.

Theory predicts that tighter correlation between floral traits and weaker relationship between floral and vegetative traits more likely occur in specialized flowers than generalized flowers, favoring by precise fit with pollinators. However, traits and trait correlations frequently vary under different environments. Through detecting spatiotemporal variation in phenotypic traits (floral organ size and vegetative size) and trait correlations in four Ranunculaceae species, we examined four predictions. Overall, our results supported these predictions to a certain degree. The mean coefficient of variation (CV) of floral traits in two specialized species (Delphinium kamaonense and Aconitum gymnandrum) was marginally significantly lower than that of another two generalized species (Trollius ranunculoides and Anemone obtusiloba). The two specialized species also showed marginally significantly smaller CV in floral traits than vegetative size across the two species. The absolute mean correlation between floral and vegetative traits, or that between floral traits in species with specialized flowers was not significantly lower, or higher than that in generalized plants, weakly supporting the predictions. Furthermore, we documented a large variation in trait correlations of four species among different seasons and populations. Study of covariance of floral and vegetative traits will benefit from the contrast of results obtained from generalized and specialized pollination systems.

Effects of light on the growth and clonal reproduction of Ligularia virgaurea.

Ligularia virgaurea is a perennial herb that is widely distributed in the alpine meadow on the eastern Qinghai-Tibet plateau. We investigated the patterns of growth and reproduction of L. virgaurea under two contrasting levels of light conditions for two continuous growing seasons. Our results showed that the light effects on the maximum relative growth rate, the shoot weight ratio and the root weight ratio differed between the two growing seasons. L. virgaurea reproduced initially through rhizome in the second growing season, rather than sexual reproduction. The proportion of genets with clonal reproduction decreased under shaded conditions. A minimum genet size should be attained for clonal reproduction to begin under the shaded conditions. There was a positive linear relationship between clonal reproduction and genet size. Light level affected the allocation of total biomass to clonal structures, with less allocation under the full natural irradiance than under the shaded conditions. There seemed to be a trade-off between vegetative growth and clonal reproduction under the full natural irradiance, in terms of smaller relative growth rates of genets with clonal reproduction than those without clonal reproduction. L. virgaurea emphasized clonal reproduction under the full natural irradiance, while the plant emphasized vegetative growth under the shaded conditions.

[Relationships between seed size and seedling growth strategy of herbaceous plant: a review].

Seed size and seedling recruitment strategy are of importance in the life-history strategy of plant. In this paper, the current ecological researches at home and aboard on the relationships between seed size and seedling growth were reviewed from the aspects of the effects of seed size on seed germination and seedling emergence, the relationships between seed size and seedling growth traits, and the relationships between seed size and seedling survival and competition ability. Some suggestions on future researches in this field were put forward. There were likely different relationships between seed size and seedling growth in different microenvironments and vegetation types, and the effects of seed size on seedling growth could result in different contributions of different seed-size species to the seedling recruitment of vegetation. The large-scale community level and the small-scale intra- and inter-species level researches on this issue should be strengthened, which would have significance for the recruitment and renewing of natural vegetation.

On the balance between niche and neutral processes as drivers of community structure along a successional gradient: insights from alpine and sub-alpine meadow communities.

BACKGROUND AND AIMS: Neutral theory predicts that the diversity and relative abundance of species in ecological communities do not depend on their specific traits. This prediction remains controversial, as many studies suggest that variations in the niches of species determine the structure of communities. The aim of this study was to test empirically the relative importance of niche and neutral processes as drivers of species abundance within plant communities along a successional gradient. METHODS: Information on the abundance (density and frequency) and traits (aboveground individual biomass and seed mass) of > 90 species was collected in alpine and sub-alpine meadows of the Tibet Plateau (China). A successional gradient (1, 3, 15 and 30 years after abandonment) was established in a sub-alpine meadow. The relationships between species traits and their abundance were evaluated using regression models. KEY RESULTS: Seed mass was negatively related to both species density (r = -0.6270, P < 0.001) and frequency (r = -0.5335, P = 0.005) in the 1-year meadow. Such relationships disappeared along the successional gradient evaluated (P > 0.07 in the 3-, 15- and 30-year meadows). Data gathered in all sites showed a significant negative relationship between the average individual biomass of a given species and its density within the community (r < -0.30, P < 0.025 in all cases). CONCLUSIONS: The results show that seed mass was a key driver of species abundance in early successional communities, and that niche forces may become more important as succession progresses. They also indicate that predictions from neutral theory, in its current form, do not hold for the meadow communities studied.

Attenuation of beryllium induced hepatorenal dysfunction and oxidative stress in rodents by combined effect of gallic acid and piperine.

We determined a minimum effective dose of gallic acid (3,4,5-trihydroxy benzoic acid; 50 mg/ kg, i.p.) and piperine (10 mg/kg, p.o.) through their therapeutic potential and further evaluated them individually and in combination against beryllium-induced biochemical alterations and oxidative stress consequences in female albino rats. The administration of beryllium altered blood biochemical variables by significantly depleting hemoglobin, albumin and urea, whereas it enhanced bilirubin and creatinine. The release of serum transaminase, lactate dehydrogenase and gamma-glutamyl transpeptidase was significantly greater, and was concomitant with a decrease in serum alkaline phosphatase. A significant increase in lipid peroxidation and a decrease in glutathione, superoxide dismutase and catalase in the liver and kidney was an indication of oxidative stress due to beryllium exposure. Individual administration of gallic acid and piperine moderately reversed the altered biochemical variables, whereas the combination of these was found to completely reverse the beryllium-induced biochemical alterations and oxidative stress consequences. We concluded that gallic acid exerts a synergistic effect when administered with piperine and provides a more pronounced therapeutic potential in reducing beryllium-induced hepatorenal dysfunction and oxidative stress consequences.

Copper deficiency in yaks on pasture in western China.

The clinical signs of a disorder in yaks (Bos grunniens), known locally as "swayback ailment," in the Qing Hai-Tibetan Plateau are described. The purpose of this study is to investigate the possibility that swayback ailment is iron (Fe)-induced copper (Cu) deficiency. The mean concentrations of Cu in soil and forage from affected areas and unaffected areas are similar and within the normal ranges. The mean concentrations of Cu in blood and hair from the affected yaks was significantly lower (P < 0.01) than that in unaffected yaks. The mean concentrations of Fe in soil and forage were significantly higher (P < 0.01) in affected than in unaffected areas. Affected yaks showed a hypochromic microcytic anemia and a low level of ceruloplasmin. Oral administration of copper sulphate prevented and cured the disease. We conclude that "swayback disorder" of yaks is caused by secondary Cu deficiency, mainly due to the high Fe content in forage.