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Objective To observe the clinical therapeutic effect on migraine treated with acupuncture combined with blood-letting therapy. Methods A total of 90 patients of migraine were included in compliance with the requirement and divided into a blood-letting therapy group, a western medication group, an acupuncture plus blood-letting therapy group, 30 cases in each one according to the random number table. In the two control groups, the simple blood-letting therapy was exerted at Dazhuī (大椎 GV14) and the oral administration with carbamazepine were provided respectively. In the acupuncture plus blood-letting therapy group, acupuncture was exerted at Baihui (百会 GV20) and other points, with blood-letting therapy combined. The treatment was given once daily and 12 treatments were as one course. After 2 courses of treatment, the score of therapeutic effect on symptoms and signs, pain score of visual analogue scale(VAS) and clinical therapeutic effect were compared among the three groups before and after treatment. Results At the end of treatment, the scores for symptoms and signs and VAS score were reduced obviously as compared with those before treatment in the three groups (all P 0.05). The total effective rate in the acupuncture plus blood-letting therapy group was higher obviously than either the blood-letting therapy group or the medication group (both P Conclusion Acupuncture combined with blood-letting therapy achieves a better clinical therapeutic effect on migraine as compared with either simple blood-letting therapy or medication. Such combined treatment obtains a satisfactory therapeutic results and deserves to be promoted in clinical application.

Plant diversity exerts significant effects on ecosystem functioning. However, it remains unclear that whether the ecological consequences of genotypic diversity of the dominant species is similar to that of species diversity. In this study, diversity effects on biomass of 12 companion species and 12 genotypes of the dominant species (Stipa grandis) in the Inner Mongolia Steppe of China were examined by two independent diversity experiments. In order to explain the diversity effects, seven plant functional traits for each species or each genotype of S. grandis per mixture treatment were measured and their Rao’s quadratic entropy (FDQ) was estimated. There was significantly positive net species diversity effect on aboveground biomass, which was mainly contributed by complementarity effect; however, net diversity effects were not significant in genotypic diversity experiment. The FDQ among S. grandis genotypes was significantly lower than that among the companion species, and the relatively lower FDQ would increase niche overlap and limit complementarity effect among genotypes. Neither species diversity nor genotypic diversity of S. grandis showed significant influences on belowground biomass, suggesting the non-consistent results of diversity effect between belowground and aboveground systems. The present finding highlighted the species diversity effects on biomass, the role of FDQ on explaining complementarity effect by niche overlap or resource use efficient.

Plant phenotypic plasticity is a common feature that is crucial for explaining interspecific competition, dynamics and biological evolution of plant communities. In this study, we tested the effects of soil CaCO3 (calcium carbonate) on the phenotypic plasticity of a psammophyte, Artemisia ordosica, an important plant species on sandy lands in arid and semi-arid areas of China, by performing pot experiments under different CaCO3 contents with a two-factor randomized block design and two orthogonal designs. We analyzed the growth responses (including plant height, root length, shoot-leaf biomass and root biomass) of A. ordosica seedlings to different soil CaCO3 contents. The results revealed that, with a greater soil CaCO3 content, A. ordosica seedlings gradually grew more slowly, with their relative growth rates of plant height, root length, shoot-leaf biomass and root biomass all decreasing significantly. Root N/P ratios showed significant negative correlations with the relative growth rates of plant height, shoot-leaf biomass and root length of A. ordosica seedlings; however, the relative growth rate of root length increased significantly with the root P concentration increased, showing a positive correlation. These results demonstrate that soil CaCO3 reduces the local P availability in soil, which produces a non-adaptive phenotypic plasticity to A. ordosica seedlings. This study should prove useful for planning and promoting the restoration of damaged/degraded vegetation in arid and semi-arid areas of China.

A dominant species of steppe in northern China, Stipa grandis, is gradually being replaced by S. krylovii due to climate change events. The aim of this study was to explore how conditioned soil, nitrogen (N) resource, and competitor influenced the responses of S. grandis and S. krylovii. We planted S. grandis and S. krylovii monoculture and mixture in each of four conditioned soils with two N treatments and analyzed which factor(s) significantly influenced the plant–soil feedbacks (PSFs), competitiveness, and N-addition effects of each species by general linear model univariate analysis. Competitor but not nitrogen significantly influenced PSFs of both S. grandis and S. krylovii. Compared with PSFs in monoculture, the negative PSFs of S. grandis were suppressed and PSFs of S. krylovii shifted from positive to negative in mixture. Competitor only significantly influenced the N-addition effects on S. krylovii; nitrogen only significantly influenced the competitiveness of S. krylovii. The highest competitiveness of S. krylovii was obtained in S. grandis conditioning soil with high N treatment. Compared with any of the other growth conditions, soil conditioned by S. grandis with high N treatment could increase S. krylovii’s competition superiority by increasing its competitiveness and N-addition effect.

Terrestrial plants in natural populations can adjust their morphologies and structures in response to different environmental conditions by genetic differentiation and environmental modification (phenotypic plasticity). The adaptive mechanisms for quantitative variation of 7 Stipa krylovii populations were evaluated using a combination of experiments performed in a field and a common garden. (1) In the common garden experiment, the quantitative traits of S. krylovii differed significantly (P

Endophytic fungi and arbuscular mycorrhizal (AM) fungi are important components of grassland ecosystem. Endophytes can reduce colonization rates of their host plants by AM fungi. In this study, Achnatherum sibiricum, infected by Epichlo sibiricum (Es) or E. gansuensis (Eg), was adopted as experimental material. The effect of Epichlo endophyte culture filtrate, root exudates and aqueous extracts from the leaves (including fresh and dead leaves) on the spore germination rates of AM fungi (Glomus mosseae and Glomus etunicatum) were evaluated. The results showed that culture filtration of Epichlo endophyte significantly inhibited the germination rate of AM fungi spores. Root exudates of infected plants only significantly inhibited the germination of G. etunicatum spores, and such effect was not related to the endophytic species. The leaf aqueous extracts had no significant effect on the germination rate of G. mosseae spores. Only the aqueous extract of Es-infected dead leaves significantly reduced the spore germination rate of G. etunicatum. In natural ecosystem, Epichlo endophytes are normally internally hosted in plants, which may affect the spore germination of AM fungi by affecting the root exudates of the host plants.内生真菌与丛枝菌根(AM)真菌是构成草原生态系统的重要组成部分.内生真菌会抑制其宿主植物的AM真菌侵染率.本研究以感染2种香柱菌属内生真菌[

Whether plants are able to adapt to environmental changes depends on their genetic characteristics and phenotypic plastic responses. We investigated the phenotypic responses of 7 populations of an important dominant species in semi-arid steppe of China - Stipa grandis, and then distinguished which adaptive mechanism(s), phenotypic plasticity or local adaptation, was/were involved in this species to adapt to environmental changes. (1) All traits were significantly influenced by the interaction of population and growth condition and by population in each condition, and inter-population variability (CVinter) was larger in the field than in the common garden for 8/9 traits, indicating that both phenotypic plasticity and genetic differentiation controlled the phenotypic differences of S. grandis. (2) From a functional standpoint, the significant relationships between the values of traits in the common garden and the environmental variables in their original habitats couldn’t support local habitat adaptation of these traits. (3) Low CVintra, low quantitative differentiation among populations (Q ST ), and low plasticity shown in the western populations indicated the very low adaptive potential of S. grandis to environmental changes. (4) From the original habitats to the common garden which is far away from S. grandis distribution region, positive phenotypic responses were found in several populations, indicating that some original habitats have become unfavorable for S. grandis.

Enclosures (fenced, grazing or clipping) within a certain period of years are the most common tools for restoration of degraded grasslands in temperate regions. Short-term enclosures can improve biodiversity and productivity by effectively relieving grazing pressure, while long-term enclosures can reduce species diversity. We therefore carried out a field experiment to investigate the specific causes of the reduced species diversity in Hulunbeier grassland of northern China. After eight years of enclosure, the significantly increased soil available nitrogen (AN) and available phosphorus (AvP) in enclosure community reduced nitrogen (N) limitation but most vegetation was still N limited. Many environmental factors led to decreased species richness, but increased soil AN and decreased light intensity at the community bottom were the most significant ones. Community density decreased independently of soil nutrition but significantly related to decreased species richness. Density of dominant canopy species increased, while dominant understory species decreased during assemblage-level thinning; therefore, the random-loss hypothesis was not supported. The dominant understory species responded to lower light availability by increasing their height, leaf area, and chlorophyll content. Moreover, our results were expected to provide some specific guidance for the restoration mode selection of degraded grasslands in northern China.

Switching expansion reduction (SER) uses a switch valve instead of the throttle valve to realize electronically controlled pressure reduction for high pressure pneumatics. A comprehensive and interactive pneumatic simulation model according to the experimental setup of SER has been built. The mathematical model considers heat exchanges, source air pressure and temperature, environmental temperatures and heat transfer coefficients variations. In addition, the compensation for real gas effect is used in the model building. The comparison between experiments and simulations of SER indicates that, to compensate the real gas effect in high pressure discharging process, the thermal capacity of air supply container in simulation should be less than the actual value. The higher the pressure range, the greater the deviation. Simulated and experimental results are highly consistent within pressure reduction ratios ranging from 1.4 to 20 and output air mass flow rates ranging from 3.5 to 132 g/s, which verifies the high adaptability of SER and the validity of the mathematic model and the compensation method.

The effect of infection by the fungal endophyte Neotyphodium, host genotype, and their interaction on growth and physiology, as well as photosynthesis, was investigated in the native grass Achnatherum sibiricum. We artificially inoculated the endophyte into mature tillers of endophyte-free A. sibiricum. Plants were clipped to 5 cm height after recording growth traits, and analyzed for total nonstructural carbohydrates (TNC %), the percentage of nitrogen (N %), and carbon (C %) in leaves before and after clipping. In our study, the prominent host genotype–endophyte infection interactions detected in A. sibiricum indicates that, for many growth and storage traits, endophyte infection can impact a little change. However, there is no overriding consistently positive effect of the endophyte on growth or storage in A. sibiricum before or after clipping. Our study showed that the interaction between endophyte and host grasses was highly contingent on plant genotypes. We found host genotype overrode fungal endophyte infection in influencing tiller number and photosynthetic properties of A. sibiricum before clipping. After clipping, host genotype accounted for more of the variation in regrowth and above-ground biomass of A. sibiricum than endophyte infection. Our study showed that host genotype affected the total nonstructural carbohydrates of A. sibiricum before and after clipping, whereas endophyte infection increased the carbon content after clipping. Genotype by infection interactions for plant height, leaf mass, total nonstructural carbohydrates, and photosynthetic characteristics indicated genotype-specific effects of endophytes on A. sibiricum physiology and photosynthetic capacity. The host genotype–endophyte infection interactions detected in A. sibiricum suggest that host genotype overrides fungal endophyte infection on growth, physiology, and nutrient content of this native grass. In contrast, endophyte effects did not appear to positively affect growth, physiology, or photosynthetic capacity before or after clipping.

Multi-layers parallel plates perfusion bioreactor has the potential advantage in cells cultivation of tissue engineering and good scalability for cells cultivation on a large scale. It is necessary to analyze the distribution of flow shear stress (FSS) of bioreactors which has strong influence on the growth of cells. The result of meshing was not satisfactory because of the complexity of multi-layers parallel plates when using computational fluid dynamics (CFD) to analyze the FSS, and the amount of calculation was great and complex especially under the process of influence on FSS caused by analyzing the different structure. The new method of simplified flow field analysis was presented in this paper, which was based on relation between FSS and flow and made the process simpler by analyzing distribution of rate instead of FSS. The simulation result showed that this method can satisfy the requirement of precision and provide reference for the analysis of the flow field which had the established relationship between structural parameters and laminar flow within it.

Caragana species are commonly distributed in desert regions. We hypothesized that the photosynthetic traits of desert Caragana species could acclimated well to the desert environments, which are characterized by high temperature, intense radiation, and low moisture. To test our hypothesis, we studied the responses of photosynthesis to light, temperature and humidity, and fluorescence parameters of four Caragana species from desert region and one Caragana species from steppe region in Inner Mongolian Plateau. The desert Caragana species had higher light compensation point, light saturation point, optimum temperature for photosynthesis, and lower optimum relative air humidity for photosynthesis than the steppe Caragana species, and their net photosynthesis rates (Pn) were higher under high temperature, intense sunlight, and low humidity. The nonphotochemical quenching efficiency (NPQ) and minimal fluorescence (Fo) of the desert Caragana species were higher, and the values of maximum fluorescence (Fm), maxim...

Disturbance can affect biomass allocation of plants, but can it influence plant reproductive behavior? To address this issue, we performed field plant community investigations and explored the reproductive behaviors of Stipa grandis and Stipa krylovii in response to grazing and mowing treatments at Maodeng pasture of Xilinguole League of Inner Mongolia, China during 2007–2009. The results showed that, with a similar niche width for the two plant species under mowing and grazing treatments, mowing significantly increased the ratio of ramet to genet number of S. krylovii and the carbon to nitrogen ratio of S. grandis, and grazing significantly decreased the ratio of vegetative to reproductive tiller biomass of S. grandis and increased the ratio of vegetative to reproductive tiller number of S. krylovii. Regression analysis showed that the significantly positive effect of root to shoot biomass ratio was stronger on the ratio of vegetative to reproductive tiller number of S. grandis than on that of S. krylovii. These results indicated that grazing and mowing influenced the reproductive manner and the process of sexual reproduction of S. grandis and S. krylovii.

Over the past several decades, grassland degradation has become severe in Inner Mongolia, leading to decreased grass coverage and increased distribution of Caragana microphylla. In order to find out new explanation for the expansion of C. microphylla in degraded grassland, we grew two-year seedlings in phosphorus (P) deficient soil supplemented with P supply ranging from 0 to 60 mg kg-1. The simulation parameters of light response curves and chlorophyll fluorescence parameters were all generally similar among different soil P supplies. Only maximum total photosynthetic rate (Pmax) and PSII potential activity (Fv/Fo) were reduced at 0 mg kg-1 soil supply, and high P supply caused P toxicity. C. microphylla was non-limited by P-deficiency and adapted well to the low-P Inner Mongolia steppe. The advantage of C. microphylla in P-limited natural grassland provided new explanation for the expanding of C. microphylla in degraded Inner Mongolia steppe.

Trade-off between vegetative growth and reproduction is an important plant adaptive strategy to environmental variability. The study investigated the Stipa grandis resource allocation and the relationship between its sexual reproduction and climate factors among three sites located along a typical environmental gradient in the Inner Mongolian Plateau. The results show that different climatic characteristics among three habitats cause the growth differentiation of S. grandis. S. grandis exhibits a prominent change on the resource allocation patterns. The number of reproductive tillers and panicles biomass allocation are significantly increased along the gradient of water availability and temperature whereas the number of vegetative tillers and root biomass allocation are reduced. The rate of the percentage increase is prominently reduced although the foliage allocation increased. It suggests that under the environments with drought and high temperature, S. grandis allocates more resources to sexual reproduction but reduces the investment in vegetative growth and asexual reproduction. Moreover, the amount of precipitation in April and May are significantly correlated with the sexual reproductive allocation of S. grandis.

Phosphorus (P) is one of the limiting mineral nutrient elements in the typical steppe of Inner Mongolia, China. In order to find out the adaptive strategy of Caragana microphylla to low soil P status, we grew plants in P-deficient soil in April 2009 and gave a gradient of P addition ranging from 0 to 60 mg(P) kg−1(soil) from May 2010. Leaf traits were measured in September 2010. Both leaf growth and light-saturated photosynthetic rate (P max) were similar among different groups. Leaf nitrogen (N):P ratio indicated that the growth of C. microphylla was not P-limited in most of the Inner Mongolia typical steppe, which had an average soil available P content equal to 3.61 mg kg−1. The optimal P addition was 20 mg(P) kg−1(soil) for two-year-old plants of C. microphylla. Leaf mass area (LMA) and leaf dry matter content (LDMC) were enhanced with low P, and significantly negatively correlated with photosynthetic N-use efficiency (PNUE). Photosynthetic P-use efficiency (PPUE) increased with decreasing soil P and increasing leaf inorganic P (Pi): organic P (Po) ratio, and showed no significant negative correlation with LMA or LDMC. P max of C. microphylla did not decline so sharply as it was anticipated. The reason for this phenomenon might be due to the increased PPUE through regulating the leaf total P allocation. C. microphylla had high P-use efficiency via both high PPUE and long P-retention time at low-P supply. The adaptation of C. microphylla to low-P supply provided a new explanation for the increased distribution of the species in the degraded natural grassland in Inner Mongolia, China.

In this study, we examined the alterations in canopy size and reproduction of Caragana stenophylla along the climatic drought gradient on the Inner Mongolia Plateau, China. We found that the canopy area and height of C. stenophylla increased gradually with increase of drought stress from the semi-arid zone to the strongly arid zone. The proportions of sexual reproduction decreased and the asexual reproduction increased with increase of the climatic drought stress. The majority of C. stenophylla offspring grew (separately) outside shrubs in the semi-arid (63.9%) and the arid zones (45.8%). But in the strongly arid zone, C. stenophylla offspring only grew inside shrubs. With the increase of climatic drought stress the ramet radius increased, while the spacer length decreased. In both the semi-arid and arid zones, the spacer length was more than 2 times of the ramet radius. Thus, some spaces were kept between the crowns of ramets. On the other hand, the spacer length was less than 2 times of the ramet radius in the strongly arid zone, so that the crowns were closely intertwined. Our results demonstrate that with the increase of climatic drought stress and associated desertification, the reproduction of C. stenophylla changes from more sexual reproduction to more clonal propagation; offspring establishment strategy changes from having more outside-shrub offspring to having only inside-shrub offspring; the clonal architecture changes from guerrilla type to phalanx type. Alterations in the reproduction of C. stenophylla along the climatic drought gradient result due to an increase of its canopy size from the northeast to the southwest on the Inner Mongolia Plateau.

There has been a dramatic shift in dominance from Stipa grandis communities to S. krylovii communities in the Inner Mongolia steppe of China, in recent decades due to climate change and human activity. We examined the growth and carbohydrate allocation pattern of S. grandis and S. krylovii under controlled conditions. The experimental approach involved a drought stress treatment and a simulated defoliation (clipping) treatment of both species. Growth (above ground biomass and root biomass) and carbon allocation (concentration of leaf total phenolics and pool of total non-structural carbohydrate) variables were evaluated at the end of the experiment. Responses to drought stress differed significantly between S. grandis and S. krylovii. For S. krylovii, growth and the pool of total non-structural carbohydrate were more negatively affected by drought stress, whereas concentration of total phenolics was positively affected. Drought stress reinforced responses to defoliation, and drought stress × defoliation interaction was significant for all of the variables. There was a distinct defoliation response level for growth after drought stress between the two species. For aboveground biomass, both species responded positively to drought stress, which changed from responses equivalence to S. krylovii being superior; for root biomass, the two species responded oppositely to drought stress, which changed from S. grandis being superior to S. krylovii being superior. There was a weak and reverse defoliation response level for the carbon allocation pattern after drought stress between the two species, with S. krylovii changing from superior in defense to superior in storage. These results suggested that S. grandis utilized an avoidance strategy (investment in defense compounds) and S. krylovii utilized a tolerance strategy (investment in storage for regrowth) in response to defoliation under drought stress, supporting the idea that stress-tolerant species may become the new dominant species because of their ability to re-grow after disturbance. This provided a possible explanation for the replacement of S. grandis communities from the view point of adaptive strategy.

Nutrient nitrogen and water availability are co-limiting factors for grassland productivity in the Inner Mongolian steppe. The objective of this study was to evaluate the interactive effects of water and nitrogen (N) addition on soil abiotic factors and soil nematode community composition. A 3-year experiment with addition of water (with and without irrigation simulating wet year precipitation) and nitrogen (0, 25, and 50 kg N ha−1) was conducted at two sites in Inner Mongolia with histories of heavy grazing (HG) and moderate grazing (MG). The results showed that HG had several lower nematode ecological indicators; namely, the Simpson index (P

Genetic variability in random amplified polymorphic DNA (RAPD) was studied in 90 individuals of Caragana microphylla, an outcrossing perennial shrub species, from five natural populations sampled in Inner Mongolia steppe of China on a small scale. Nineteen selected primers were used to amplify DNA samples, and totally 225 bands were detected. The percentage of polymorphic bands within populations ranged form 58.22% to 63.56%, with an average of 60% at the population level and 71.11% at the species level, indicating relatively high genetic variations in C. microphylla species. Shannon’s information index (l) and Nei’s gene diversity (h) showed the similar trend with each other. According to the analysis of Nei’s gene diversity, the percentage of genetic variation among populations was 7.13%, indicating a low level of genetic differentiation among populations. There existed a strong gene flow (N m = 3.26) among populations. Although AMOVA analysis also revealed most variation was within populations (ΦST = 4.1%), a significant proportion was observed among populations (P < 0.001) in the present study, suggesting genetic differentiation occurred among populations at a certain extent. Based on Mantel’s tests and the results of previous studies, the genetic structure pattern of C. microphylla accorded with the isolation-by-distance model on a very large scale, however, on a small scale, the significant genetic differentiation among populations might be enhanced by the micro-environmental divergence among the sampling sites, rather than by geographic factors. Analysis of the genetic variations of C. microphylla populations provided useful information for the adaptive strategy of Caragana species.

Symbiotic relationships with microbes may influence how plants respond to environmental change. Here, we investigated how fungal endophyte infection affected the growth of a native grass under altered water and nutrient availability. In a two-month field experiment, we compared the performance of endophyte-infected (EI) and endophyte-free (EF) Achnatherum sibiricum subjected to four treatments comprised of a factorial combination of two levels of water availability and two levels of fertilization. The greatest benefits of endophyte infection occurred in the well-watered fertilized treatment. With reduced water and/or nutrient availability, the benefits declined. EI plants subjected to drought and fertilization had higher root:shoot ratios and allocated more nitrogen to photosynthetic machinery and thus had a higher net photosynthetic rate than EF counterparts. In the well-watered unfertilized treatment, EF plants allocated more nutrients to photosynthetic machinery, while EI plants allocated more resources to defense. Thus EI plants were superior to EF plants in terms of nutrient conservation. In the drought unfertilized treatment, no significant difference occurred between EI and EF plants. Our results support the idea that the endophyte-grass interactions are dependent on available resources. However, we did not find a clear cost of endophyte infection. For A. sibiricum, fertilizer addition resulted in greater benefits of the symbiosis for plant growth, but this advantage decreased under drought.

Little attention has been paid to the role of soil organic matter (OM) in the formation of pedogenic carbonate in desert soils. The relationships among soil OM, soil dehydrogenase activity (DHA), and soil CaCO3 inaplantcommunity dominated by Artemisia ordosica, located on the eastern boundary of Tengger Desert in the Alxa League, Inner Mongolia, China, were studied to understand whether OM was directly involved in the formation of pedogenic carbonate. The results showed that DHA and CaCO3 positively correlated with OM content, and DHA, OM, and CaCO3 were correlated with each other in their spatial distribution, indicating that abundant OM content contributed to the formation of CaCO3. Therefore, the formation of pedogenic CaCO3 was a biotic process in the plant community dominated by A. ordosica.

The physiological characteristics of four dominant Caragana species (Caragana korshinskii, Caragana stenophylla, Caragana tibetica and Caragana roborovskyi) in the desert region of the Inner Mongolia Plateau were studied. These were compared with a semi-arid species of the same genus, Caragana microphylla, in order to understand physiological adaptation mechanisms of Caragana species to desert environments. Leaf osmotic potential of the four desert Caragana species was more negative than that of C. microphylla, and turgor potential was higher. The concentrations of soluble sugars and inorganic ions in the desert Caragana species were higher than those of the semi-arid species. Leaf water content and water potential of the four desert Caragana species were relatively low, as was the free water content, while bound water content and the ratio of bound water to free water were high. These characters favoured extracting and retaining water and enhanced resistance to drought and heat stresses. The four desert Caragana species had low stomatal conductance and transpiration rate, and high water-use efficiency (WUE), indicating a water-saving strategy. In addition, the four desert Caragana species had higher peroxidase (POD) and superoxide dismutase (SOD) activities. As a result, the free radical content was not higher, and sometimes lower, than that of C. microphylla in the semi-arid area. In conclusion, Caragana species adapt to the arid environment through effective osmotic adjustment, low transpiration, high WUE, and by efficient removal of free radicals.

We studied the vessel features of ten populations of three Caragana species (C. microphylla Lam, C. davazamcii Sancz, C. korshinskii Kom.), which form a geographical cline in the inner Mongolia Plateau of China. All sampled shrubs had common vessel features of xeric plants, such as coexistence of wide and narrow vessels in one xylem, high vessel density, short element length, distinct helical thickenings, which were all associated with strong drought resistance. The quantitative vessel features changed gradually along the geographical gradient of the three Caragana species. Mean vessel diameter, D100, generally decreased from the east to the west. However, D95 (the mean diameter of vessels responsible for 95% of the total stem conductance) changed in an opposite direction to D100, which might be attributed to different proportions of wide and narrow vessels of the ten populations. The more xeric the habitat was, the smaller the proportion of wide vessels (which contributed mainly to water conductance). There was also a tradeoff between efficiency and safety in water transport. The intervessel pit size, density of vessel elements, intervessel pits and helical thickenings increased from the east to the west with the increase of environmental aridity. The trend of vessel element length and wall thickness was similar to that of D100, i.e. they decreased from the east to the west. All these gradually changing features confirmed the geographical transition among the three Caragana species, and indicated an order of drought resistance as C. korshinskii>C. davazamcii>C. microphylla.

We used Achnatherum sibiricum, a native grass as test material and application of methyl jasmonate (MJ) to simulate herbivory, and compared the growth and physiological characters of endophyte-infected (EI) and endophyte-free (EF) plants. The results showed that MJ treatment significantly decreased the shoot growth, but significantly increased the concentrations of defensive substances such as total phenolic and lignin, and decreased the size of aphid population. Endophyte infection significantly increased the tiller number, total phenolic and lignin contents in the shoot. As for shoot biomass and total phenolic in the root, they were affected by MJ treatment. Without MJ treatment, no significant differences were found in shoot biomass or root phenolic content whether the plants were infected by endophyte or not. With MJ treatment, the shoot biomass was significantly lower and the shoot phenolic content was significantly higher in EI plants than in EF plants. Endophyte infection significantly increased resistance of the host plant to aphids, and the beneficial effect was enhanced by MJ treatments, after three applications with MJ, there were no aphids on EI plants. Overall, endophyte infection could alter the allocation pattern of the host plant between growth and defense, and MJ treatments further strengthened the defensive ability of the host plant at the cost of growth.

Random amplified polymorphic DNA (RAPD) analysis was used to characterize the genetic diversity and population genetic structure of Stipa krylovii populations in Inner Mongolia steppe of North China. Thirteen 10-bp oligonucleotide primers, which generated 237 RAPD bands, were used to analyze 90 plants of five populations from three regions, meadow steppe, typical steppe and desert steppe, from the east to the west. The genetic diversity of Stipa krylovii that was revealed by observed number of alleles (na), expected number of alleles (ne), Nei’s diversity index (h), Shannon’s diversity index (H), amplificated loci, polymorphic loci and the percentage of polymorphic loci (PPB) increased from the east to the west. The Pearson’s correlation analysis between genetic diversity parameters and ecological parameters indicated that the genetic diversity of Stipa krylovii was associated with precipitation and cumulative temperature variations along the longitude (humidity were calculated by precipitation and cumulative temperature). Dendrogram based on Jaccard’s genetic distance showed that the individuals from the same population formed a single subgroup. Although most variation (56.85%) was within populations, there was high genetic differentiation among populations of Stipa krylovii, high differentiation within and between regions by AMOVA analysis. Either Nei’s unbiased genetic distance (G ST) or gene flow (Nm) among pairwise populations was not correlated with geographical distance by Mantel’s test (P > 0.05), suggesting that there was no consistency with the isolation by distance model in these populations. Natural selection may have played a role in affecting the genetic diversity and population structure, but habitat destruction and degradation in northem grassland in China may be the main factor responsible for high genetic differentiation among populations, within and among regions.

Domestic rubbish compost is a complex-polluted system, containing multiple heavy metals, which limits its application. In the present study, Cr, Mn, Ni, Cu, Zn, Cd, and Pb accumulation and ecological responses of turfgrass to rubbish compost were investigated following the addition of EDTA. The results showed that the addition of EDTA significantly increased heavy metal accumulation in Lolium perenne L. and Festuca arundinacea L. Most heavy metal concentrations in L. perenne increased with increasing EDTA supply. The concentrations of Cr, Mn, Ni, Cu, and Cd in L. perenne were highest following the addition of 30 mmol/kg EDTA and the concentrations of Cr and Ni at this point reached concentrations of 1914.17 and 521.25 μg/g, respectively. When the EDTA level was 20 mmol/kg. The highest concentrations of Mn, Ni, Cu, and Zn in F. arundinacea reached 268.01, 110.94, 161.52and 1 354.97 μg/g, respectively, following the addition of 20 mmol/kg EDTA. The EDTA-induced increase in the accumulation of heavy metals in turfgrass was plant-and metal-specific. L. perenne had a relatively high ability to accumulate Cr, Ni, and Zn. The highest Zn concentration was 2 979.58 μg/g and, following the addition of EDTA, the concentrations of the three metals were increased 26.23, 20.03, and 10.49–fold, respectively, compared with control. However, F. arundinacea showed a high ability to accumulate Cr, with the highest concentration (596.02 μg/g) seen following the addition of 30 mmol/kg EDTA; the concentration of Cr increased 15.51-fold compared with control. With EDTA addition, ecological responses of both turfgrass species showed that EDTA at concentrations 20 mmol/kg inhibited these parameters significantly for both species. Moreover, EDTA increased the chlorophyll and proline content at all concentrations tested. On the basis of the synthetic remediation index, the optimal EDTA concentration for turfgrass remediation of heavy metals in compost is approximately 10 mmol/kg. (Managing editor: Ya-Qin HAN)

A study on the effects of silicon supply on the resistance to drought in cucumber plants was conducted in pot experiments. The results suggested that in the absence of stress, silicon slightly enhanced the net photosynthetic rate, but significantly decreased the transpiration rate and stomatal conductance in cucumber plants. Silicon enhanced the net photosynthetic rate of cucumber plants under drought stress. Since silicon decreased the stomatal conductance, enhanced the capacity of holding water, and kept the transpiration rate at a relatively steady rate during drought stress, the photosynthesis of the cucumber plants was sustained. And under drought stress, silicon increased the biomass and water content of leaves in cucumber plants. Silicon decreased the decomposition of chlorophyll in cucumber plants under drought stress, limited the increase of the plasma membrane permeability and malondialdehyde (MDA) content in leaves, alleviated the physiological response of peroxidase (POD) to drought s...

Plant calcium (Ca) is composed of dissociated Ca2+ and easily soluble, slightly soluble, and hard soluble combined Ca salts. The hard soluble Ca salts can often engender Ca crystals. To understand the Ca status in different growth form plants in salinized habitats, 54 plant species were sampled from the salinized habitats in Tianjin, with the Ca crystals examined by microscope and the Ca components determined by sequential fractionation procedure. More Ca crystals were found in 38 of the 54 plant species. In 37 of the 38 plant species, drusy and prismatic Ca oxalate crystals dominated, whereas the cystolith of Ca carbonate crystal only appeared in the leaves of Ficus carica of Moraceae. The statistics according to growth form suggested that deciduous arbors and shrubs had more Ca oxalate crystal, liana had lesser Ca oxalate crystal, and herbs and evergreen arbors had no Ca oxalate crystal. From arbor, shrub, liana to herb, the concentration of HCl-soluble Ca decreased gradually, while that of water soluble Ca was in adverse. The concentration of water soluble Ca in herbs was significantly higher than that in arbors and shrubs. This study showed that in salinized habitats, plant Ca crystals and Ca components differed with plant growth form, and the Ca oxalate in deciduous arbors and shrubs played an important role in withstanding salt stress.

A pot experiment was conducted to study the effects of inoculation with root-knot nematodes on the cucumber leaf N and P contents, and the rhizospheric and non-rhizospheric soil pH and enzyme activities. The rhizospheric soil pH didn't have a significant decrease until the inoculation rate reached 6000 eggs per plant. With the increase of inoculation rate, the leaf N and P contents, rhizospheric soil peroxidase activity, and rhizospheric and non-rhizospheric soil polyphenol oxidase activity all decreased gradually, rhizospheric soil catalase activity was in adverse, non-rhizospheric soil pH decreased after an initial increase, and non-rhizospheric soil catalase activity had no regular change. After inoculation, rhizospheric soil urease activity decreased significantly, but rhizospheric and non-rhizospheric soil phosphatase activity and non-rhizospheric soil peroxidase activity only had a significant decrease under high inoculation rate. In most cases, there existed significant correlations between rhizospheric soil pH, enzyme activities, and leaf N and P contents; and in some cases, there existed significant correlations between non-rhizospheric soil pH, enzyme activities, and leaf N and P contents.

An investigation was conducted on the vegetative and reproductive biomass allocation of Stipa grandis at the hill-top and hill-foot of Xilingol grassland, and relatedness- and factor analyses were made to study the effects of hill position on the S. grandis seed biomass. Significant differences were observed in the vegetative and reproductive growth of S. grandis plants at the hill-top and hill-foot. At hill-foot, the height and number of non-flowering S. grandis ramets increased by 24.69% and 35.37%, respectively, the number of flowering ramets increased by 102.97%, the vegetative, reproductive, and total biomass increased by 44.14%, 95.59% and 47.45%, respectively, and the 100-grain mass increased by 25.00%, as compared with those at hill-top. The seed biomass of S. grandis at hill-top was mainly affected by soil moisture content, while that at hill-foot was mainly affected by soil pH. Hill position induced the differentiation of soil moisture and N contents, and made the S. grandis at the fertile hill-foot allocating more energy to its sexual reproduction.

Seven kinds of heavy metal accumulation of rubbish compost in turfgrass by EDTA chelating were investigated. With EDTA application, heavy metal accumulation by two species of turfgrass was increased significantly. The enrichment coefficients of Lolium perenne L(L) and Festuca arundinacea L(F) to Cr reached 9.45 and 6.15 respectively. In the range of EDTA dosages given, heavy metal accumulation in turfgrass increased with increasing EDTA level. There were significant differences in remediation of different metals by applying EDTA. L had high ability to accumulate Cr, Cd, Ni and Zn, showing better remediation to heavy metals of rubbish compost. In contrast, F showed high ability to accumulate Cr, Ni, Cu and Zn. Low EDTA level increased aboveground net primary production (ANP) of turfgrass, but EDTA would considerably inhibit it when EDTA was higher than 20 mmol/kg. The results demonstrated that the optimum dosage of EDTA for remediating heavy metals in rubbish compost by turfgrass was between 10 mmol/kg and 20 mmol/kg.

Aims: In cool-season grasses, systemic and vertically transmitted Epichloe infections often provide a suite of benefits including increased growth, reproduction and competitive abilities. However, these effects of Epichloe endophytes on their hosts often depend upon host and endophyte genotype and environmental factors. Methods: Achnatherum robustum (sleepygrass) harbors at least two Epichloe species within natural populations in the Southwest USA. We tested the effects of endophyte infection and species, host population and plant genotype (by experimentally removing the endophyte), and soil moisture (a key limiting factor) on growth and drought stress response of infected A. robustum plants from two populations (Weed and Cloudcroft) in the Sacremento Mountains of New Mexico, USA). Important Findings: Although the two populations harbor distinct Epichloe species each with very different chemoprofiles, neither endophyte status (infected vs. uninfected) nor endophyte species affected most growth parameters at 8 or 25 weeks of the experiment, except for leaf length. In high water treatment, infected plants from the Weed population had longer leaf length compared with uninfected plants. In contrast, the population of origin affected all growth parameters, including plant height, leaf number, length and width, tiller number and shoot and root biomass, as well as wilting time. Grasses from the Cloudcroft population generally showed greater growth than grasses from the Weed population. Endophyte infection did affect wilting time, with infection in the Weed population generally reducing time to wilting under low and high water, whereas infection in the Cloudcroft population reduced time to wilting only under high water conditions. Our results suggest that plant population and their associated plant genotypes may play a much larger role in endophyte–host grass interactions in varying environments than previously thought. Asexual Epichloe species may be compatible with only specific host genotypes within populations such that the phenotypic effects due to population may be greater than phenotypic changes influenced by variation in the endophyte.