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Mangrove soil is a reliable source for screening cellulose-degrading bacteria due to the high diversity of microbes. To effectively utilize crop straw resources, a cellulolytic bacterium, Paenibacillus silvae strain CH2 was isolated from mangrove soil. We determined the carboxymethyl cellulose (CMC) and filter paper assay (FPA) activities of CH2 at different incubation times, NaCl concentrations, pH and temperatures, estimated the degradation efficiencies of rice and maize straw by CH2, sequenced and analyzed the whole genome of CH2. The results showed that along with the increases of incubation time, NaCl concentration, pH and temperature, the CMC and FPA activities increased first and then decreased . The highest CMC and FPA activities were observed at incubation time of 72-84 h, NaCl concentration of 6.0 g·L -1 , pH of 7 and temperature of 36 ℃. Degradation of straw assays revealed that CH2 could effectively degrade rice and maize straw. At 0 g·L -1 NaCl (the control), the 10-day degradation rates of rice and maize straw were 30.4% and 47.0%, respectively. In the presence of 15 g·L -1 NaCl, the degradation rates were not significantly different from the control, indicating that CH2 had a high tolerance to salts. The whole genome of P. silvae CH2 was 6797325 bp, containing 6312 coding genes. P. silvae CH2 contained multiple genes encoding cellulose and hemicellulose degrading enzymes. These enzymes mainly belonged to the GH family, including endo-1,4-β-xylanase, Xylan 1,4-β-xylosidase, β-glucosidase, and endoglucanase. The results indicated that the bacterium had the potential to be used in crop straw degradation.

High intensity grazing is considered as an important cause of grassland degradation. Numerous studies have explored effects of grazing activities on grassland ecosystems. Nevertheless, the research regarding grazing activity itself, especially the quantification methods and gradient division of grazing pressure, is relatively insufficient. Based on a total of 141 Chinese and English papers containing keywords such as 'grazing pressure', 'grazing intensity', and giving specific quantification methods and classification standards, we sorted out the definition, quantification methods, and grading standards of grazing pressure. The results showed that the definition of grazing pressure in current studies could be classified into two categories: considering the number of livestock carried in the current grassland ecosystem only from the perspective of the amount of grazing livestock; or considering the impacts or consequences on grassland ecosystems. Small-scale manipulative experiments mainly quantified and divided gra-zing pressure by controlling the number of livestock, grazing duration, grazing area, etc . Ecosystem responses to grazing activities were also converted by the above indicators, while the large-scale data spatialization method only considered number of livestock per unit area. The method of remote sensing inversion focused on ecosystem responses, that is, the impacts of grazing activities on grasslands, and it was difficult to separate the role of climatic factors. The quantitative standards of grazing pressure in different grassland types were quite different, even in the same grassland type, and such difference was directly related to grassland productivity.

In order to clarify the influence of livestock grazing managements on C:N:P stoichiometry of grassland ecosystem and improve grassland management ability at global scale, 83 Chinese and English papers were selected for meta-analysis in this study. We explored the effects of grazing herbivore assemblage (sheep alone, cattle alone, and mixed cattle and sheep) and grazing intensity (light grazing, moderate grazing and heavy grazing) on leaf, litter, root and soil C, N and P stoichiometry of grassland ecosystems. The results showed that grazing significantly decreased C content, C/N and C/P, and increased N, P content and N/P in leaf and litter. C content, N content, C/P and N/P were significantly reduced, and P content and C/N were increased in root and soil. Leaf and litter stoichiometry were more sensitive to cattle and sheep grazing alone, while root and soil stoichiometry were more sensitive to mixed grazing. Heavy grazing had a greater impact on the stoichiometry of grassland ecosystems. Grazing reduced soil N content and increased P content, indicating that grazing had different pathways of influence on grassland N and P content. Further research on the mechanisms of N and P content changes in response to unbalanced grazing activities and the incorporation of the effects of grazing herbivore assemblage and intensity into models for predicting and managing grassland ecosystems could effectively improve grassland ecosystem management.

Amorpha fruticosa and Amygdalus pedunculata are common plant species used for greening construction in arid and semi-arid region of Northwest China. In order to explore the feasibility of greening construction and ecological restoration by A. fruticose with A. pedunculata , we exami-ned the allelopathic effects of five concentrations of aqueous leaf extracts of A. fruticosa (0.025, 0.05, 0.10, 0.15 and 0.20 g·mL -1 ) on eight A. pedunculata varieties (YY 1 , YY 3 , YY 4 , YY 5 , YY 6 , SM 6 , SM 7 and SM 8 ), using the methods of paper-petri dish and soilless culture. The results showed that when the concentration of A. fruticosa leaf extracts were 0.025 and 0.05 g·mL -1 , the seed germination and seedling growth of YY 1 and SM 6 were significantly better than other varieties. With increasing concentration of A. fruticosa leaf extracts, the catalase activity of A. pedunculata seedlings first increased and then decreased. The activities of peroxidase and superoxide dismutase, and the contents of soluble protein and chlorophyll showed a downward trend, while the contents of malondialdehyde and soluble sugar and the permeability of cell membrane gradually increased. Results of the principal component and cluster analysis showed that the growth potential of A. pedunculata decreased with the order of YY 1 , SM 6 , SM 8 , SM 7 , YY 6 , YY 3 , YY 5 and YY 4 under the allelopathic effect of A. fruticose . In conclusion, the artificial collocation and mixed planting of low-density of A. fruticosa with YY 1 and SM 6 were beneficial to seed germination and seedling growth of A. pedunculata .

Landscape structure and spatial pattern are the core issues in landscape ecology. The application of graph theory provides a research framework for landscape pattern analysis. Landscape graph based on graph theory is gradually applied to the connectivity modeling of biodiversity conservation and decision support of landscape planning. The representation, analysis and application of landscape graph have become a hot topic in conservation biology and landscape ecology. In this review, we first introduced the graph theory basis of landscape map. Based on the Scopus database, 257 published journal papers with the words "landscape graph", "connectivity" and "network" in titles, abstracts, and keywords from 1993 to 2019 were retrieved. We analyzed the research progress and development trend of this field from the aspects of annual published papers, journal sources, research areas, research institutions and landscape types involved. The results showed that before 2017, the number of journal papers published showed an overall increasing trend, and after 2017, the annual number of published papers decreased year by year. The main research forces were concentrated in United States, France, Canada, and China, contributing to 86.8% of the total published papers. Most of the research results were published in "Landscape Ecology", "Landscape and Urban Planning", and "Biological Conservation". In the research content, the representation of landscape graph mainly included the definition of nodes, the measurement of edges and the simulation of landscape. The analysis of landscape graph involved analysis index and landscape graph partitioning. This study mainly focused on the application of landscape graph in science and practice, including biodiversity conservation, landscape (ecological network) planning and management, the assessment of landscape impacts. Landscape graph based on graph theory influences conservation science and planning practitioners by helping understand landscape connectivity changes, animal behavior and habitat conservation. The impact of graph theory on conservation science and planning comes from the rich theoretical basis and mature research methods. Landscape graph based on graph theory provides a springboard for ecological understanding of landscape structure and pattern, and is an important tool for global researchers and practitioners.

Velvetleaf ( Abutilon theophrasti ) is a common weed in dryland, which can reduce crop yield. Allelopathy is one of the possible reasons resulting in crop yield reduction. In this study, we analyzed the allelopathic effect of velvetleaf volatile oil components on germination and seedling growth of three dryland crops, wheat ( Triticum aestivum ), maize ( Zea mays ), and soybean ( Glycine max ). A total of 26 compounds in velvetleaf volatile oil were identified by GC-MS, accounting for 98.1% of the total chromatographic peak areas. The terpenes with lower molecular weight in the volatile oil were α-pinene, eucalyptol, α-terpinolene, β-terpinene, trans-α-ionone, and trans-β-ionone. The saturated aqueous solution of velvetleaf volatile oil could inhibit seed germination of three crops by filter paper and soil. Velvetleaf volatile oil could inhibit the seedling growth of three crops through air, filter paper, and soil. Wheat was the most susceptible to volatile oil, followed by maize and soybean. The inhibitory effect of volatile oil on the growth of wheat was the strongest in air medium, followed by filter paper and soil medium. The lower molecular weight of terpene components from volatile oil might be the important allelochemicals.

We examined the effects of root extracts of Haloxylon ammodendron and Beta vulgaris in Chenopodiaceae extracted by water and ethanol on seed germination and haustorium formation of Cistanche deserticola by filter paper culture dish method. The results showed that only adding root extract had no effect on seed germination and haustorium formation of C. deserticola . The germination rate of C. deserticola seeds treated by adding 10 mg·kg -1 gibberellin to the root extracted by ethanol was not significantly different from that of the control (GA 3 ), whereas those treated by adding gibberellin to the ethanol extract of two kinds of host root was increased by more than 10 times. The germination rate of C. deserticola seeds in the treatment with adding 1 mg·kg -1 fluridone (FL) to root extract was not significantly different from that in the control with only fluridone, while those in the treatment with B. vulgaris root water extraction was the highest (39.4%). Compared to the treatment of adding gibberellin to the root extract, the germination rate of C. deserticola seeds was only increased. When FL was added to the host root extract, the haustorium was formed on the germination tube, with the formation rate of the ethanol extraction group being the highest (16.2%). Seed germination rate of C. deserticola increased to 52.3% when GA 3 and FL were added to the ethanol extract of H. ammodendron , but the formation rate of haustorium was not different from that of FL treatment. Only 6.7% of the seed formation haustorium in the control was significantly lower than that in FL treatment. There were differences in the position and shape of the haustorium of C. deserticola seeds under different treatments. The haustorium produced by adding the extract of the host root mostly appeared at the top of the bud tube, and many papillae raised into claws. The haustorium of FL treatment without adding the extract of the host root mostly appeared at the bottom or the top of the bud tube splitting. The results indicated that ethanol extraction and water extraction could extract the substances that could promote the formation of C. deserticola seeds haustorium from the host root, but did not affect seed germination. GA 3 and FL could significantly improve the germination rate of C. deserticola seeds, but the formation of the haustorium was affected by some substances in the host root extract.

Mycorrhizae, formed through the colonization of soil mycorrhizal fungi into the roots of host plants, are common symbiosis in the terrestrial ecosystems. The establishment of mycorrhizae is mainly based on the bidirectional nutrient exchanges between the symbiotic partners. Mycorrhizal fungi can absorb mineral nutrients, such as nitrogen and phosphorus, from soil and transport them to the host plants for their growth. As an exchange, host plants supply mycorrhizal fungi with the carbohydrates in the form of lipids or sugars, which are essential for fungal growth. In recent years, the mechanism of nutrient exchange between the mycorrhizal fungi and host plants has been a hot research topic. Important progresses have been achieved in mechanisms of host plants nutrient uptake and transport mediated by the mycorrhizal fungi. In this review, recent advances in nutrient exchange between arbuscular mycorrhizal fungi, ectomycorrhizal fungi and host plants were summarized, especially in the absorption and bidirectional transfer mechanisms of important nutrients, such as carbon, nitrogen and phosphorus. The potential regulatory effects of nutrient exchange in the mycorrhizal development were also reviewed. In addition, key problems and prospects of related researches were analyzed. This paper would be meaningful for the establishment of mycorrhizal model and the optimization of mycorrhizal effects.

Atmospheric nitrogen deposition has complex effects on individual plants and terrestrial ecosystems. We synthesized results from 39 published papers (16 papers in English and 23 papers in Chinese) and conducted a meta-analysis to evaluate the general responses of tree root traits to nitrogen addition, and further analyzed the difference of N-induced results between English papers and Chinese papers. Our results showed that N addition significantly increased fine root diameter (+6.7%), fine root N content (+8.9%), and root respiration rate (+17.5%), but did not affect fine root biomass, fine root length, specific root length, fine root C content, and fine root C:N ratio. Different climatic zone and fertilizer types had different effects on the experimental results. In addition, experimental results published in English papers were generally more significant than those in Chinese papers. We summarized the general effects of N addition on tree root systems, and further analyzed the mechanisms underlying the effects of N enrichment on forest ecosystem carbon cycle.

The health of wetland ecosphere in an estuarine delta is determined by many factors, such as continuity of natural processes, ecosystem connectivity, habitat heterogeneity, and food web diversity. The contradiction between ecological and environmental protection and regional development in the estuarine delta is becoming more and more prominent. A series of man-made and natural processes directly and indirectly resulted in habitat fragmentation of wetlands, which has direct and strong impacts on the ecosphere health and the habitat function of wetlands. In this paper, we provided a perspective on researches on the basic theory of healthy wetland ecosphere, landscape ecological network system, hydrologic network construction, key food webs, and habitat heterogeneity. At the regional and landscape scales, with the linkages between land use and ecosystem integrity as the main line, we clarified the influences of habitat fragmentation on wetland ecological functions, especially the effects of landscape integrity and river connectivity on wetland habitat. At the community and ecosystem scales, emphasis should be given on the relationship between food web and ecosystem stability, especially the supporting role of food web diversity and habitat heterogeneity on the construction of wetland biosphere. Further efforts should focuse on the wetland habitats construction based on landscape integrity, hydrologic connectivity, habitat heterogeneity and food web diversity. These efforts could help to develop and optimize the theory and method of constructing wetland ecosphere and enhancing its ecological function, and promote the sound development of regional ecological environment and resource utilization in estuarine deltas.

FQA, which uses the conservatism of plant species for particular habitats and the species richness of plant communities, is a rapid method for the assessment of habitat quality. This method is based on species composition of quadrats and coefficients of conservatism for species which assigned by experts. Floristic Quality Index (FQI) that reflects vegetation integrity and degradation of a site can be calculated by a simple formula and be used for space-time comparison of habitat quality. It has been widely used in more than ten countries including the United States and Canada. This paper presented the principle, calculation formulas and application cases of this method, with the aim to provide a simple, repeatable and comparable method to assess habitat quality for ecological managers and researchers.

Soil environmental function regionalization is of significance for soil environmental classification management in China. In this paper, we discussed the broad and narrow concept of soil environmental function and its corresponding attributes. Based on the constraint analysis on the soil environmental quality to function, relationship between soil environmental function and quality was illustrated. Compared with different methods and indices of soil environmental function regionalization, we established the index system of soil environmental function regionalization according to the soil environmental suitability and function. The proposed draft of soil environmental function regionalization included four first-class function types, 10 second-class function types, and 75 soil environmental functional areas. According to the differences among those functional areas, we proposed corresponding management countermeasures. The results provided scientific basis for the control and prevention of soil pollution and the control of regional risk in China.

The paper studied the effects of altitude on reproductive characteristics in 12 populations of Saussurea przewalskii at the eastern Qinhai-Tibetan Plateau, China. The results showed that the size, reproductive organ biomass, vegetative organ biomass, capitulum number, and seed number of individual plant decreased with the increasing altitude, and the capitulum mass and hundred-grain mass increased continuously. S. przewalskii could ensure its reproduction by reducing plant body size to decrease resource consumption, and increasing the allocation of limit resources to flower biomass. In order to ensure sexual reproduction, the reproductive allocation of the plants increased with increasing the altitude. There was a trade-off between capitulum number and capitulum mass, and between seed number and hundred-grain mass, which allowed the plants to maximize their fitness under stressful conditions.

The ecological process models are powerful tools for studying terrestrial ecosystem water and carbon cycle at present. However, there are many parameters for these models, and weather the reasonable values of these parameters were taken, have important impact on the models simulation results. In the past, the sensitivity and the optimization of model parameters were analyzed and discussed in many researches. But the temporal and spatial heterogeneity of the optimal parameters is less concerned. In this paper, the BIOME-BGC model was used as an example. In the evergreen broad-leaved forest, deciduous broad-leaved forest and C3 grassland, the sensitive parameters of the model were selected by constructing the sensitivity judgment index with two experimental sites selected under each vegetation type. The objective function was constructed by using the simulated annealing algorithm combined with the flux data to obtain the monthly optimal values of the sensitive parameters at each site. Then we constructed the temporal heterogeneity judgment index, the spatial heterogeneity judgment index and the temporal and spatial heterogeneity judgment index to quantitatively analyze the temporal and spatial heterogeneity of the optimal values of the model sensitive parameters. The results showed that the sensitivity of BIOME-BGC model parameters was different under different vegetation types, but the selected sensitive parameters were mostly consistent. The optimal values of the sensitive parameters of BIOME-BGC model mostly presented time-space heterogeneity to different degrees which varied with vegetation types. The sensitive parameters related to vegetation physiology and ecology had relatively little temporal and spatial heterogeneity while those related to environment and phenology had generally larger temporal and spatial heterogeneity. In addition, the temporal heterogeneity of the optimal values of the model sensitive parameters showed a significant linear correlation with the spatial heterogeneity under the three vegetation types. According to the temporal and spatial heterogeneity of the optimal values, the parameters of the BIOME-BGC model could be classified in order to adopt different parameter strategies in practical application. The conclusion could help to deeply understand the parameters and the optimal values of the ecological process models, and provide a way or reference for obtaining the reasonable values of parameters in models application.

In recent years, studies on carbon sequestration of biochar in soil has been in spotlight owing to the specific characteristics of biochar such as strong carbon stability and well developed pore structure. However, whether biochar will ultimately increase soil carbon storage or promote soil carbon emissions when applied into the soil? This question remains controversial in current academic circles. Further research is required on priming effect of biochar on mineralization of native soil organic carbon and its mechanisms. Based on the analysis of biochar characteristics, such as its carbon composition and stability, pore structure and surface morphology, research progress on the priming effect of biochar on the decomposition of native soil organic carbon was reviewed in this paper. Furthermore, possible mechanisms of both positive and negative priming effect, that is promoting and suppressing the mineralization, were put forward. Positive priming effect is mainly due to the promotion of soil microbial activity caused by biochar, the preferential mineralization of easily decomposed components in biochar, and the co-metabolism of soil microbes. While negative priming effect is mainly based on the encapsulation and adsorption protection of soil organic matter due to the internal pore structure and the external surface of biochar. Other potential reasons for negative priming effect can be the stabilization resulted from the formation of organic-inorganic complex promoted by biochar in the soil, and the inhibition of activity of soil microbes and its enzymes by biochar. Finally, future research directions were proposed in order to provide theoretical basis for the application of biochar in soil carbon sequestration.

As a kind of globally widely distributed soil microorganism, arbuscular mycorrhizal (AM) fungi form the symbiosis with the majority of land plants, which is important for plant nutrition and ecosystem functioning. Few vascular species are considered to be nonmycorrhizal, especially those within the families Amaranthaceae, Chenopodiaceae, Carophyllaceae and Brassicaceae. At present, the interactions between these non-host plants and AM fungi are few and scattered, lacking systematic summary. In this paper, the type of non-host plants, the reason of low mycotrophy, and the effect of AM network formed by neighbor plants on AM fungi colonization on the non-host, and the possible interaction between AM fungi and non-host, as well as the material exchange between plants and AM fungi and their possible ecological functions were reviewed in order to give some new ideas on the function of the nonmycorrhizal plants in the fragile ecosystems.

Under the background of "missing carbon sink" mystery and carbon capture and storage (CCS) technology development, this paper summarized the lime material flow process carbon sink from the lime carbonation principles, impact factors, and lime utilization categories in chemical industry, metallurgy industry, construction industry, and lime kiln ash treatment. The results showed that the lime carbonation rate coefficients were mainly impacted by materials and ambient conditions; the lime carbon sink was mainly in chemical, metallurgy, and construction industries; and current researches focused on the mechanisms and impact factors for carbonation, but their carbon sequestration calculation methods had not been proposed. Therefore, future research should focus on following aspects: to establish a complete system of lime carbon sequestration accounting method in view of material flow; to calculate lime carbon sequestration in both China and the world and explain their offset proportion of CO 2 emission from lime industrial process; to analyze the contribution of lime carbon sequestration to missing carbon sink for clarifying part of missing carbon sinks; to promote the development of carbon capture and storage technology and provide some scientific bases for China's international negotiations on climate change.

Ecosystem service flow is the key point and difficulty of ecosystem services research, which is now at the initial stage and show a developing trend of quantity and spatialization. However, the term "ecosystem service flow" is ambiguous. In this paper, we presented two descriptions about the term, and two corresponding theories and methods: the transmission of a service from ecosystems to people and distributed ecosystem model, and the flow of benefits accruing to people as generated by stocks of ecosystem structure and grey/black box theory. Then the latest researches related to the two descriptions were listed, and their merit and demerit were summarized. Finally, we pointed out several directions for future research in ecosystem service flow. Especially, the use of newest space technology and information technology (such as big data) and comprehensive understanding of ecosystem services (such as taking urban ecosystem services flow and abiotic flow into account) should be stressed in the future research.

This paper analyzed the niche breadth and niche overlap of dominant species of forest community in Xiaowutai Mountain, and fitted the response patterns of dominant species to the environment gradients by generalized additive models. The results showed that a total of 392 species of vascular plants, belonging to 222 genera, 75 families were recorded in 148 quadrats. A total of 36 dominant species were selected from the tree layer, shrub layer and herb layer by importance va-lues. Betula albosinensis, Betula platyphylla, Larix principis-rupprechtii, Pinus tabuliformis at the tree layer, Spiraea pubescens, Abelia biflora, Rosa bella, Corylus mandshurica at the shrub layer, Carex breviculmis, Deyeuxia arundinacea, Sanguisorba officinalis, Carex siderosticta at the herb la-yer had higher niche breadth, and these species had greater competitiveness and stronger environmental adaptability. In the same layer, niche overlap index was high indicating that species had similar habitats, and there was competitive relationship between them. Although Acer momo and Quercus wutaishanica had high niche overlap, their competition was not strong in the condition of rich resources. There was niche overlap between B. platyphylla and a variety of mixed tree species including A. momo, Q. wutaishanica, Sorbus alnifolia, and limited resources leaded to strong competition in these communities. The adaptability of each species to environmental factors was diffe-rent. The response of most dominant species to altitude showed a single peak curve, and they distri-buted within a certain altitude range. The response of some dominant species to altitude was linearly increased or decreased, and concentrated at high altitudes or low altitudes. The response of dominant species to slope position was similar to altitude. The dominant species showed a linear change along the slope, showed significantly positive correlation with soil temperature, and showed the cha-racteristics of shade-requiring or sunny-requiring. The response of B. albosinensis, A. biflora, H. bretschneideri, C. breviculmis, C. dahurica to litter layer thickness and soil thickness showed linearly increased. The response of L. principis-rupprechtii, B. albosinensis, P. fruticosa, D. arundinacea to soil moisture showed linearly increased, while linearly decreased to soil electrical conductivity. Most dominant species to soil pH and environmental disturbance showed a single peak curve, and the others showed linearly decreased.

The winter reproductive areas of Puccinia striiformis var. striiformis in Sichuan Basin are often the places mostly affected by wheat stripe rust. With data on the meteorological condition and stripe rust situation at typical stations in the winter reproductive area in Sichuan Basin from 1999 to 2016, this paper classified the meteorological conditions inducing wheat stripe rust into 5 grades, based on the incidence area ratio of the disease. The meteorological factors which were biologically related to wheat stripe rust were determined through multiple analytical methods, and a meteorological grade model for forecasting wheat stripe rust was created. The result showed that wheat stripe rust in Sichuan Basin was significantly correlated with many meteorological factors, such as the ave-rage (maximum and minimum) temperature, precipitation and its anomaly percentage, relative humidity and its anomaly percentage, average wind speed and sunshine duration. Among these, the average temperature and the anomaly percentage of relative humidity were the determining factors. According to a historical retrospective test, the accuracy of the forecast based on the model was 64% for samples in the county-level test, and 89% for samples in the municipal-level test. In a meteorological grade forecast of wheat stripe rust in the winter reproductive areas in Sichuan Basin in 2017, the prediction was accurate for 62.8% of the samples, with 27.9% error by one grade and only 9.3% error by two or more grades. As a result, the model could deliver satisfactory forecast results, and predicate future wheat stripe rust from a meteorological point of view.

Heterotrophy of zooxanthellae symbiotic corals refers to the nutrition directly coming from food absorption, not the nutrition obtained from photosynthesis. Most ex situ propagation of symbiotic corals focused on the effects of irradiation, flow rate and water quality on corals, few of them involved in the demand and supply of coral heterotrophic nutrition. This paper reviewed the significance of heterotrophic nutrient supply to symbiotic corals from the sources of coral heterotrophic nutrition, the factors affecting the supply of coral heterotrophic nutrient, and the methods of how to study the coral heterotrophy. In general, the research of coral heterotrophy is just at the beginning stage, and future studies should focus on the inherent mechanism of coral feeding selection and developing more effective research methods.

Eco-innovation is an important way to realize sustainable development. It has the dual positive externality of "knowledge spillover" and "environmental spillover", which has attracted much attention from theory and practice. In order to systematically grasp the current situation of eco-innovation, this study collected the relevant foreign literatures on eco-innovation in the past ten years, and made a systematic review of the definition, characteristics and dimensions of eco-innovation. Focusing on the theory of institutional theory, stakeholder theory and resource-based view, this paper explored the antecedents of eco-innovation. Then, this paper also demonstrated the positive and negative effects of eco-innovation on corporate financial performance, and the meditating and moderating mechanisms between eco-innovation and financial performance. Finally, based on the limitations of existing research, the future research direction was put forward.

Thermal dissipation probe (TDP) was used to continuously measure the sap flux density (F d ) of Pinus tabuliformis and Hippophae rhamnoides individuals in hilly Loess Plateau, from June to October 2015, and the environmental factors, i.e., photosynthetic active radiation (PAR), water vapor pressure deficit (VPD), and soil water content (SWC), were simultaneously monitored to clarify the difference of rainfall utilization between the two tree species in a mixed plantation. Using the methods of a Threshold-delay model, stepwise multiple regression analyses, and partial correlation analyses, this paper studied the process of F d in these two species in response to the rainfall pulses and then determined the effects of environmental factors on F d . The results showed that, with the increase of rainfall, the response percentages of F d in both P. tabuliformis and H. rhamnoides increased at first but then decreased; specifically, in the range of 0-1 mm rainfall, the F d of P. tabuliformis (-16.3%) and H. rhamnoides (-6.3%) clearly decreased; in the range of 1-5 mm rainfall, the F d of P. tabuliformis decreased (-0.4%), whereas that of H. rhamnoides significantly increased (9.0%). The lower rainfall thresholds (R L ) of F d for P. tabuliformis and H. rhamnoides were 6.4 and 1.9 mm, respectively, with a corresponding time-lag (τ) of 1.96 and 1.67 days. In the pre-rainfall period, the peak time of F d of P. tabuliformis converged upon 12:00-12:30 (70%), while the F d of H. rhamnoides peaked twice, between 10:30 and 12:00 (48%) and again between 16:00 and 16:30 (30%). In the post-rainfall period, the peak time of F d of P. tabuliformis converged upon 11:00-13:00 (40%), while that of H. rhamnoides peaked twice, between 12:00 and 13:00 (52%) and again between 16:30 and 17:00 (24%). Among the environmental factors, the rank order of factors associated with the F d of both P. tabuliformis and H. rhamnoides was PAR>VPD, before rainfall. However, the rank order of factors influencing the F d of P. tabuliformis was PAR>VPD>0-20 cm SWC (SWC 0-20 ), whereas this order was different for H. rhamnoides: SWC 0-20 >PAR >VPD, after rainfall. This mixed plantation of P. tabuliformis and H. rhamnoides trees had a high stability of water utilization.

By using the open top chambers (OTCs) fumigation method, this paper investigated the changes of foliar injury, level of reactive oxygen species (ROS), activities and gene expression of antioxidant enzymes in Ginkgo biloba leaves under different ozone (ambient ozone≈40, 80, 160, 200 nmol·mol -1 ) concentrations, in order to study the effects of elevated ozone (O 3 ) concentrations on reactive metabolism. The results showed that the obvious foliar injuries were observed in 160 and 200 nmol·mol -1 O 3 treatments, while no visible injury was observed in 80 nmol·mol -1 O 3 and ambient O 3 treatments. After 20 d, a significant increase in O 2 -· generation rate was observed in G. biloba leaves exposed to 160, 200 nmol·mol -1 O 3 , compared with ambient ozone and 80 nmol·mol -1 O 3 , and there were no significant differences between ambient O 3 and 80 nmol·mol -1 treatments. After 40 d, H 2 O 2 content of G. biloba leaves in 160 and 200 nmol·mol -1 O 3 was significantly higher than that in 80 nmol·mol -1 and ambient ozone, respectively. The activities of catalase (CAT) in 160 and 200 nmol·mol -1 treatments were also significantly higher than that in 80 nmol·mol -1 and ambient O 3 treatments. The ascorbate peroxidase (APX) activity of leaves for each elevated O 3 treatment was lower than that of ambient ozone. The level of CAT and APX expression increased progressively after 40 d O 3 treatment. The expression intensity of GbD was conspicuously strengthened along with the increase of ozone concentration and fumigation time. Le-vel of reactive oxygen increased, activities of antioxidant enzyme decreased, level of gene expression down-regulated, and foliar visible injury was observed in leaves of G. biloba in elevated ozone stress.

The effects of different intensities of UV-B radiation on photosynthetic characteristics, photosynthetic pigment content and chloroplast ultrastructure of Phragmites australis were studied in this paper. The results showed that enhanced UV-B radiation significantly reduced the net photosynthetic rate, stomatal conductance and transpiration rate, and the degree of degradation increased with the increasing irradiation intensity. The intercellular CO 2 content increased and the photosynthetic efficiency decreased significantly compared with the control. Enhanced UV-B radiation decreased photosynthetic pigment contents, including chlorophyll a, chlorophyll b, total chlorophyll and carotenoid, and the decrement increased with the increasing irradiation intensity. Under the enhanced UV-B radiation treatment, chloroplast structure was damaged, and thylakoid lamellae was disorde-red, swelling and even blurred. The effect of high intensity of radiation on chloroplast ultrastructure was greater than that of lower intensity of radiation.

The changing trend of soil available phosphorus (Olsen-P) content in soil and its relationship with soil phosphorus surplus and crop yield are fundamental when making appropriate phosphate fertilizer recommendations. In this paper, the influences of long-term fertilization on crops phosphorus uptake, soil phosphorus surplus, changing trend of soil available phosphorus content and relationships of soil available phosphorus content with soil phosphorus surplus and crop yield were investigated through 34 years (1981-2015) long-term trial in loessial soil region on the Loess Plateau. The experiment had a completely-randomized-block split-plot design in triplicate. Two main-plot treatments were no farmyard manure and farmyard manure (M), and four subplot treatments were CK (no fertilizer), N (application of chemical fertilizer N), NP (application of chemical fertilizer NP) and NPK (balanced application of chemical fertilizer NPK), respectively. The results showed that fertilization treatments and crop types significantly influenced uptake amount of phosphorus and soil phosphorus surplus. Averaged over time from 1981 to 2015, wheat mean phosphorus uptake amounts of CK, N, NP, NPK, M, MN, MNP and MNPK were 8.63, 10.64, 16.22, 16.21, 16.25, 17.83, 20.39 and 20.27 kg·hm -2 , while rape phosphorus uptakeamounts of eight treatments were 4.40, 8.38, 15.08, 15.71, 10.52, 11.23, 17.96 and 17.66 kg·hm -2 , respectively. The surplus amount of soil phosphorus significantly correlated with the amount of phosphorus applied to soil. When soil phosphorus surplus amount equal zero, wheat and rape phosphorus input amounts were 10.47 kg·hm -2 and 6.97 kg·hm -2 , respectively. Soil phosphorus surplus amount significantly influenced the changing trend of available phosphorus content in soil. CK and N treatments had no phosphorus input, and soil available phosphorus content exhibited a declining trend, annually decreased by 0.16 mg·kg -1 and 0.15 mg·kg -1 , respectively. In contrast, NP, NPK, M, MN, MNP and MNPK six treatments were applied with phosphate fertilizer every years, and available phosphorus content gradually increased along with the duration of trial, with annual increase by 0.02-0.33 mg·kg -1 . Soil available phosphorus content significantly correlated with phosphorus accumulative surplus amount, and the linear models were y=0.012x+9.33 and y=0.009x+11.72 in manure and no manure treatments, respectively. In no manure treatments, wheat yields significantly positively correlated with soil available phosphorus content, however, in manure treatments, their relationships did not reach a significant level. The relationship of wheat grain yield with available phosphorus content could be significantly fitted by piecewise linear model, and available phosphorus agronomy threshold of wheat was 14.99 mg·kg -1 . Rape grain yield also increased with increasing soil available phosphorus content, but the relationship was not significant. This indicated when soil available P content is higher than 14.99 mg·kg -1 , application of phosphate fertili-zer should be reduced or even avoided for planting wheat in loessial soil region on the Loess Plateau.

Soil reservoir is the basis of stable grain production and sustainable development in dry farming area. Based on the long-term field experiment, this paper investigated the changes of soil moisture in wheat field located in the rain-fed Changwu Tableland, and analyzed the interannual and annual variation characteristics and dynamics trends of soil reservoir from 2012 to 2015. The results showed that the vertical distribution curves of average soil water content were double peaks and double valleys: first peak and valley occurred in the 10-20 and 50 cm soil layer, respectively, while for the second peak and valley, the corresponding soil layer was the 100 and 280 cm soil layer. Soil reservoir did not coincide with precipitation for all yearly precipitation patterns but lagged behind. Yearly precipitation patterns had a great influence on the interannual and annual dynamic changes of soil reservoir. Compared with rainy year, the depth of soil moisture consumption decreased and supplementary effect of precipitation on soil moisture became obvious under effects of drought year and normal year. In rainy year, soil reservoir had a large surplus (84.2 mm), water balance was compensated; in normal year, it had a slight surplus (9.5 mm), water balance was compensated; while in drought year, it was slightly deficient (1.5 mm), water balance was negatively compensated. The dynamics of soil water in winter wheat field in the rain-fed Changwu Tableland could be divided into four periods: seedling period, slow consumption period, large consumption period, and harvest period, the order of evapotranspiration was large consumption period> seedling period> harvest period> slow consumption period.

Iron oxide is the main form of iron element existing in the soil. In subtropical areas, the high-content iron oxide constitutes the soil's important coloring components, or its mineral substances, such as goethite and hematite, making the soil color apparently different from that in other climatic zones. The present paper, with the Pearl River Delta, a typical subtropical area, as illustration, and through analysis of the correlation between different spectral forms and the content of soil iron oxide, created inversion models of soil iron oxide by extracting characteristic spectral bands. The findings showed that there was a negative correlation between the content of soil iron oxide and the reflection spectrum, and the sensitive bands were mainly found in such visible near-infrared regions such as 404, 574, 784, 854 and 1204 nm. The correlation between the spectrum through differential processing and the soil iron oxide was significantly improved. On the basis of the correlation-prominent bands, the methods of both multiple linear regression and principal component analysis were adopted so as to remove collinear bands, and finally, characteristic bands were selec-ted to serve as the input parameters of inversion models. A comparison of the results revealed that the best inversion model of soil iron oxide content in the Pearl River Delta was BP artificial neural network (i.e., RMSEC=0.22, RMSEP=0.81, R 2 =0.93, RPD=12.20). It was applicable with excellent stability to the fast estimation of the iron oxide content in the soil and could hopefully serve as the research basis for the measure of the spatial distribution of the soil iron oxide.

Dryland wheat has gone through double selections, including natural and artificial selection, in the evolutionary process. During this process, artificial selection played a key role in variety domestication and improvement. This paper summarized a few relatively independent but interrelated issues including evolutionary characteristics, physiological plasticity, morphological plasticity and population attribute transition in dryland wheat under artificial selection. It provided an overview on physiological and ecological mechanism of dryland wheat adapting to stress conditions, and an outline of wheat evolution route. In the long-term evolutionary history of dryland wheat from diploid to hexaploid, natural selection acted as a key role for wheat adaptation to stress environments. With the intervention of artificial selection, the yield-oriented phenotyping has been continuously strengthened, and morphological characteristics of wheat tended to display a fine adaptation to adverse environments at population level. As a product of artificial selection, water and nutrient use efficiencies were improved constantly, and biomass allocation pattern showed the characteristics of lowering below-ground parts and increasing above-ground parts. In the meantime, the tolerance to density and high temperature stresses tended to be enhanced, while photosynthetic rate per unit area was decreased gradually. Dryland wheat production was a complex population process, rather than a simple individual performance. Artificial selection increased population fitness and individual reproductive allocation in dryland wheat, which in turn strengthened its coordination with environment, but weakened its attributes of natural population. This paper also drew an outline of dryland wheat evolution, and provided a few suggestions for breeding strategies and cultivation management of dryland wheat under climate change.

Soil black carbon (BC) is considered to be the main component of passive C pool because of its inherent biochemical recalcitrance. In this paper, soil BC in the middle part of Great Xing'an Mountains was quantified, the distribution of BC in different particle size fractions was analyzed, and BC stabilization mechanism and its important role in soil C pool were discussed. The results showed that BC expressed obvious accumulation in surface soil, accounting for about 68.7% in the whole horizon (64 cm), and then decreased with the increasing soil depth, however, BC/OC showed an opposite pattern. Climate conditions redistributed BC in study area, and the soil under cooler and moister conditions would sequester more BC. BC proportion in different particle size fractions was in the order of clay>silt>fine sand>coarse sand. Although BC content in clay was the highest and was enhanced with increasing soil depth, BC/OC in clay did not show a marked change. Thus, the rise of BC/OC was attributed to the preservation of BC particles in the fine sand and silt fractions. Biochemical recalcitrance was the main stabilization mechanism for surface BC, and with the increasing soil depth, the chemical protection from clay mineral gradually played a predominant role. BC not only was the essential component of soil stable carbon pool, but also took up a sizable proportion in particulate organic carbon pool. Therefore, the storage of soil stable carbon and the potential of soil carbon sequestration would be enhanced owing to the existence of BC.

The transition zone from the Loess Plateau to the Qinghai-Tibet Plateau is one of the regions with most dramatic changes in agricultural production mode and most sensitive response to the carbon balance effect. This paper analyzed the carbon balance of the agriculture system along the altitude gradient in Tongwei, Weiyuan and Xiahe counties. The results showed that with the increase of altitude, the carbon emission, carbon fixation and carbon sink capacity of crops per unit area decreased accordingly, while the average carbon emission, carbon fixation and carbon source capacity of each household in livestock system increased. The integrated crop-livestock production system changed from carbon sink to carbon source. The average carbon emission of each household rose with altitude, but the carbon fixation was the opposite. The change of percentage ofhousehold in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau with carbon balance could be fitted with Logistic equation. In the crop system of Tongwei, Weiyuan and Xiahe with the altitude increase, carbon emission at the inflection point where the household percentage accounted for 50.0% was 1491, 857 and 376 kg CE·household -1 , and carbon fixation was 6187, 3872 and 778 kg CE·household -1 , respectively. For the livestock system, carbon emission was 2218, 3725 and 49511 kg CE·household -1 , and carbon fixation was 138, 230 and 2706 kg CE·household -1 , respectively. For the integrated crop-livestock system, carbon emission was 3615, 4583 and 49918 kg CE·household -1 , and carbon fixation was 6289, 4113 and 3819 kg CE·household -1 , respectively, which could be the key point for the regulation of regional carbon balance.

Continuous improvement of urban water environment and overall control of black and odorous water body are not merely national strategic needs with the action plan for prevention and treatment of water pollution, but also the hot issues attracting the attention of people. Most previous researches concentrated on the study of cause, evaluation and treatment measures of this phenomenon, and there are few researches on the monitoring using remote sensing, which is often a strain to meet the national needs of operational monitoring. This paper mainly summarized the urgent research problems, mainly including the identification and classification standard, research on the key technologies, and the frame of remote sensing screening systems for the urban black and odorous water body. The main key technologies were concluded too, including the high spatial resolution image preprocessing and extraction technique for black and odorous water body, the extraction of water information in city zones, the classification of the black and odorous water, and the identification and classification technique based on satellite-sky-ground remote sensing. This paper summarized the research progress and put forward research ideas of monitoring and screening urban black and odorous water body via high spatial resolution remote sensing technology, which would be beneficial to having an overall grasp of spatial distribution and improvement progress of black and odorous water body, and provide strong technical support for controlling urban black and odorous water body.

Pb stable isotope signatures analysis can be used to identify its sources precisely and the spatial transportation process to achieve precise management of target areas. In this study, 12 surface (0-10 cm) soil samples (3-5 replications for each site) were collected on the Yancheng coast. Pb isotopes ( 206 Pb, 207 Pb and 208 Pb) and Pb contents were analyzed by inductively coupled plasma mass spectrometry. Results showed that the soil Pb contents were as high as 1.7 times of the background Pb content value. Referencing the national criteria of GB 15618-2008, the study area was polluted by Pb to a relatively serious extent. The analysis indicated that main Pb sources of the area were local, including Sheyang Power Plant, Shuangdeng Paper Mill Sewage Plant, and Huafeng industrial area near Wanggang. Based on the normalized difference vegetation index (NDVI) and distance analysis, we figured out the key patterns of Yancheng coast to cope with the press sources.

The trophic relations of the red-crowned crane species in Zhalong Wetland, northeastern China may change significantly withrapid decrease of biological resources. In this paper, the influence of food resource exhausting on the trophic levels of this vulnerable species was determined by using stable isotope (δ 13 C and δ 15 N) methods. The results indicated that the mass of δ 13 C and 15 N in the red-crowned cranes were in the range of -17.8‰ to -18.5‰ and 6.9‰ to 8.1‰, respectively. The dominant food chain length of large water fowls in the ecosystem of Zhalong Wetland was 3.8±0.2 in average, of which the examined species, i.e., red-crowned cranes were 3.1 in average, with the range of 2.9 to 3.3. The annual fluctuation range of δ 15 N values in the red-crowned cranes was from 7.4‰ to 8.8‰ (with the gap of approximately 1.4, which was below the threshold 3.4 that was considered as a trophic level significant change in an ecosystem), indicating the trophic level of this vulnerable species did not change significantly with the losses of large area of their habitats and foods. Nevertheless, the rapid decrease of the target species population with the food resource exhausting indicated that the conflict of food demand of the red-crowned cranes versus resource need of local residents should be resolved for better protecting this extinguishable species.

As one of three major greenhouse gases, nitrous oxide (N 2 O) has solicited substantial attention. Stable isotope has been widely used to explore the sources of N 2 O emissions. Here, we briefly introduced the microbial processes involved in N 2 O emissions, and the main influencing factors. We further summarized the development of N 2 O isotope signature of δ 15 N, δ 18 O and SP (site preference of 15 N in different positions of N 2 O molecule) in exploring the N 2 O formation mechanism. The application of these techniques, especially the SP values, is still at the primary stage in China. Therefore, this paper focused on the development of the isotope ratios analysis in partitioning N 2 O sources from foreign countries, and put forward suggestions on the future research in China.

Karst regions, which account for about 15% of the terrestrial surface area, are characte-rized by specific hydrogeological structure different from most non-karst regions. Thus, many research methods that are used in non-karst regions cannot be directly used in karst regions. This issue is especially relevant to research on plant water sources. In this paper, origins and possible solutions to the common problems associated with research on water sources used by karst plant species were reviewed. Four questions were addressed: 1) why is it important to determine plant water source in karst regions? 2) Why are stable isotopes used? 3) What are the challenges associated with using stable isotopes in karst regions? 4) What are the probable solutions for these challenges? This review emphasized the advantages of using stable isotope techniques to identify sources of water used by karst plant species and the challenges associated with satisfying the prerequisites of this method. It is suggested that sources of water used by plant species in karst regions need not to be divided into specific depths and the method of identifying sources of water used by plant species based on their hydrologic properties was much applicable.

The trophic dynamics of wetland organisms is the basis of assessing wetland structure and function. Stable isotopes of carbon and nitrogen have been widely applied to identify trophic relationships in food source, food composition and food web transport in wetland ecosystem studies. This paper provided an overall review about the current methodology of isotope mixing model and trophic level in wetland ecosystems, and discussed the standards of trophic fractionation and baseline. Moreover, we characterized the typical food sources and isotopic compositions of wetland ecosystems, summarized the food sources in different trophic levels of herbivores, omnivores and carnivores based on stable isotopic analyses. We also discussed the limitations of stable isotopes in tra-cing food sources and in constructing food webs. Based on the current results, development trends and upcoming requirements, future studies should focus on sample treatment, conservation and trophic enrichment measurement in the wetland food web, as well as on combing a variety of methodologies including traditional stomach stuffing, molecular markers, and multiple isotopes.

Stable isotope analysis has been widely used in marine food web studies. An appropriate isotopic baseline is essential for calculating diet or trophic position of marine organisms when using stable isotopic data. This paper provided an overview of the selection of isotopic baselines for four ty-pical marine ecosystems, i.e. estuary and bay, neritic zone, oceanic zone, and deep sea. The interferential factors of baseline selection and the significance of compound specific stable isotope in minimizing the effects of temporal-spatial variations of isotopic baseline were summarized, and the issues needed to be solved in this field and several directions for further research were presented. It would provide a beneficial reference for further research on stable isotope ecology in marine ecosystems.

The spatiotemporal dynamic patterns of vegetation in mining area are still unclear. This study utilized time series trajectory segmentation algorithm to fit Landsat NDVI time series which generated from fusion images at the most prosperous period of growth based on ESTARFM algorithm. Combining with the shape features of the fitted trajectory, this paper extracted five vegetation dynamic patterns including pre-disturbance type, continuous disturbance type, stabilization after disturbance type, stabilization between disturbance and recovery type, and recovery after disturbance type. The result indicated that recovery after disturbance type was the dominant vegetation change pattern among the five types of vegetation dynamic pattern, which accounted for 55.2% of the total number of pixels. The follows were stabilization after disturbance type and continuous disturbance type, accounting for 25.6% and 11.0%, respectively. The pre-disturbance type and stabilization between disturbance and recovery type accounted for 3.5% and 4.7%, respectively. Vegetation disturbance mainly occurred from 2004 to 2009 in Shengli mining area. The onset time of stable state was 2008 and the spatial locations mainlydistributed in open-pit stope and waste dump. The reco-very state mainly started since the year of 2008 and 2010, while the areas were small and mainly distributed at the periphery of open-pit stope and waste dump. Duration of disturbance was mainly 1 year. The duration of stable period usually sustained 7 years. The duration of recovery state of the type of stabilization between disturbances continued 2 to 5 years, while the type of recovery after disturbance often sustained 8 years.

Methane bio-oxidation plays an important role in the global methane balance and greenhouse gases mitigation. Oxygen (O 2 ) is one of the significant factors in methane bio-oxidation. The O 2 concentration in the environments not only can affect community structure and activity of aerobic methanotrophs and the distribution of methane-derived carbon, but also aerobic methanotrophs have various ways of metabolism at different O 2 concentrations. It is meaningful for carbon cycle and biodiversity of methane-driven ecosystem to understand the hypoxia-tolerance mechanisms of aerobic methanotrophs and methane bio-oxidation in O 2 -limited environments. In this paper, the activity and community structure of aerobic methanotrophs in O 2 -limited environments were summarized. The hypoxia-tolerance mechanism of aerobic methanotrophs and the relationship between methanotrophs and non-methanotrophs in O 2 -limited environments were reviewed. Future studies about aerobic methanotrophs were also discussed.

The relationship between the distribution of halobios and environmental variables has been a focus of present research in marine ecology. Species distribution models (SDMs) have been widely employed to predict the distribution patterns and potential habitat suitability assessments of marine species and provide an efficient approach for marine biodiversity conservation, invasive species prevention, and fishery management. SDMs mainly include habitat suitability index models, mechanism models, and statistical models. In this paper, the theoretical basis of SDMs was firstly concluded and summarized. Next, the exploitation and case-studies of SDMs, especially the statistical models, for predicting potential distribution of marine species were reviewed. Then, comparisons of various methods for variable selection and model validation were made. Conclusions could be drawn that Akaike information criterion showed excellent performance when it came to variable selection, while Kappa coefficient and Area Under receiver operating character Curve (AUC) were widely used in relation to model validation. Finally, problems and prospects of SDMs were discussed. With the development of research on physiological characteristics, using mechanism models to predict potential habitats of halobios would become a trend.

Silver nanoparticles (AgNPs) as one of the most widely used metal nanomaterials can enter soil and water environment via various pathways, exert toxicity on water-borne organisms and deteriorate the aquatic eco-environment. With complex composition of natural water, the physicochemical property of AgNPs as nano materials makes their transformation process more complicated in water system. Therefore, understanding of the fate and transport of AgNPs in aqueous environment is extremely important for water quality management and protection of the eco-environment. Deve-lopment of modern science and technology has made it possible to study the process of the dissolution of AgNPs in environment. This paper summarized the source and risk of AgNPs in environment, analyzed impacts of environmental factors such as pH, dissolved oxygen, ionic strength and intrinsic factors of AgNPs such as particle size and coating on the AgNPs transformation in water environment, and summarized the main analytical techniques for the AgNPs size, potential and morphology. Finally, this paper pointed out the major research gaps in the current research and provided prospective for the future research.

The secondary Picea forest is one of the dominant vegetation types in Guandi Mountain. It's also the representative type of evergreen cold-temperate coniferous forests in subalpine region of north China. A 4 hm 2 fixed monitoring Picea forest plot was established in Pangquangou Nature Reserve, Guandi Mountain (GDS plot) to better understand the basic characteristics such as species composition, community structure and its potential ecological process and mechanisms. We analyzed species composition, structure and spatial distribution of sample forest based on the first background survey data in this paper. The results showed that a total of 30 woody plant species existed in the sample area, which belonged to 11 families, 22 genera. The total individual number (including branches) was 26218 (independent individual number was 10266). Floristic composition in the region was defined as north temperate elements. Big differences of individual number, average diameter at breast height (DBH) and basal area among different species caused significant community layering effect, and the dominant species in each layer was obvious. Size-class structure of species showed bimodal skewed normal distribution at the canopy layer, approximate normal distribution at the subtree layer, and 'L' type distribution at the shrub layer. Spatial distribution of the dominant tree species such as Picea wilsonii and Larix principis-rupprechtii showed different pattern features with the changing size class, whether in individual number or in aggregation degree. Compared with the above two species with the same size class, a large number of L. principis-rupprechtii with DBH≥30 cm aggregated in the center of sample plot, but few P. wilsonii individuals with DBH≥30 cm occurred in the plot and had no clustering distribution. Only a few L. principis-rupprechtii with DBH≤10 cm occurred in the plot with a scattering distribution, and a large number of P. wilsonii with DBH≤10 cm aggregated in the center of the plot. There were also many P. wilsonii individuals with DBH≤10 cm distributed in the northwest area of the plot, but Betula albo-sinensis individuals with DBH≤10 cm mostly distributed in the southeast area of the plot. Shrub species such as Cotoneaster acutifolius, Spiraea pubescens and Lonicera szechuanica also showed heterogeneous spatial distribution. Species distribution pattern was affected by habitat conditions, and related to its own development, regeneration traits and ecological habits.

Quorum sensing (QS), a cell-to-cell communication, regulates a variety of social beha-viors, such as biofilm formation, public goods produce and gene horizontal transfer of bacteria. In the process of quorum sensing, public goods could be utilized by any members in the population, which was termed as cooperation. Notably, public goods also could be shared by the individuals who could not produce them, which was termed as cheating. Once cheaters come up, they possibly maintain equilibrium with cooperators, meanwhile they also possibly induce the collapse of population due to their rapid growth and shortage of public goods. Therefore, invasion of cheaters arouses wide attentions in medicine, agriculture, food science and so on regarded as a new strategy to control pathogens. In this study, based on the introduction about the theory of bacterial quorum sensing cooperation and cheating, we analyzed the factors influencing the formation and development of the relationship between cooperator and cheater. Moreover, we discussed the mechanism of stabilization in the relationship between cooperator and cheater, including kin selection, metabolic prudence, metabolic constraint (gene pleiotropy) and policing quorum sensing. Finally, some problems in current researches of quorum sensing cooperation and cheating were presented as well as the future research directions. We hoped this paper could deepen the understanding of bacterial quorum sen-sing and ecology of bacterial population.

Taking'Kyoho' as the test material, the effect of white, green, red and blue bags on volatile compounds in mature grape berries was explored in this study. The results indicated that bags with different colors could create special light conditions, which resulted in the difference of volatile compounds in grape berries. A total of 37, 38, 32, 34 kinds of volatile compounds which included esters, aldehydes, alcohols, ketones, terpenes and aromatic compounds, were detected in 'Kyoho' berries covered with the white, green, red and blue bags respectively, and 33 in the control. Compared with the control, the contents of ethyl acetate, ethyl hexanoate and some other esters decreased, while hexanal, E-2-hexenal and decanal increased in berries with white bags, the contents of the major common compounds, except ethyl 3-hexenoate, ethyl (E)-hex-2-enoate, ethyl 3-hydroxybutyrate, E-2-hexenal, (E,E)-2,4-hexadienal, decanal, and phenethyl alcohol, decreased in berries with green bags, the contents of ethyl acetate, ethyl hexanoate and hexanal, E-2-hexenal decreased in berries with red bags, the contents of ethyl acetate, ethyl hexanoate and some other esters changed slightly in berries with blue bags, except for the increase of hexanal and E-2-hexenal. For those characteristic compounds, the kinds of alcohols in berries covered with bags decreased while the kinds of terpenes and aromatic compounds increased. In general, the fruits with the blue bags had the highest volatile esters, and those with the white bags had high volatile esters and aldehydes, while those with the green and red bags had low aromatic compounds.

Since China's reform and opening-up, the rapid growth of China's economy has greatly accelerated the expansion of built-up land, which has affected regional ecological environment to a great extent. Taking Jinjiang County of Fujian Province, one of the fastest economic-developing counties in the coastal areas of southeastern China, as a case study area, this paper focused on analyzing the rapid built-up land expansion process of the county and its impact on county's ecological quality using remote sensing techniques. Based on two Landsat images of 1996 and 2015 of Jinjiang, the built-up land of the county was extracted using the index-based built-up index (IBI) and its change was analyzed. In the meantime, the ecological status of Jinjiang was evaluated with a recently-proposed remote sensing based ecological index (RSEI) and the relationship between the built-up land dynamics and the ecological status changes of the county was quantitatively examined. The results showed that during the period from 1996 to 2015, the area of built-up land of Jinjiang had a net increase of 68.54 km 2 , a growth of 45%, and the expansion intensity was 0.55. The expansion of the built-up lands has caused overall degradation of the county's ecological quality. The mean value of RSEI of the county had declined from 0.532 in 1996 to 0.460 in 2015, a drop of13.5%. The area proportion of high ecological-quality grades also significantly fell from 39% in 1996 to 21% in 2015. The built-up land expansion intensity was negatively correlated with the ecological quality change.

With the development of urbanization, the effect of urban heat island has become increasingly evident. As an essential component of the urban natural landscapes, urban green space plays an important role in mitigating the effect of urban heat island. However, facing the rapid urbanization and changing environment, how to rationally plan and design the green space and realize its best cooling effect which can improve the urban environment and microclimate is still an urgent problem to be solved. So there is a strong need for mulitiscale researches on the cooling effect of urban green space. This paper systematically gave a review on the cooling effect of urban green space based on field measurement of air temperature, the main factors that influenced the cooling effect of green space were explored from three aspects including the area and shape characteristics of urban green space, the structure characteristics of vegetation and the external factors which affected the cooling effect, and the characteristics of the cooling effect of the green space were summarized from the aspect of time variation and distance decay. Then, the main problems and future research prospects of urban green space cooling effect were put forward.

The nature reserve is very important to biodiversity maintenance. However, due to the urbanization, the nature reserve has been fragmented with reduction in area, leading to the loss of species diversity. Establishing ecological network can effectively connect the fragmented habitats and plays an important role in species conversation. In this paper, based on deciding habitat patches and the landscape cost surface in ArcGIS, a minimum cumulative resistance model was used to simulate the potential ecological network of Fujian provincial nature reserves. The connectivity and importance of network were analyzed and evaluated based on comparison of connectivity indices (including the integral index of connectivity and probability of connectivity) and gravity model both before and after the potential ecological network construction. The optimum ecological network optimization measures were proposed. The result demonstrated that woodlands, grasslands and wetlands together made up the important part of the nature reserve ecological network. The habitats with large area had a higher degree of importance in the network. After constructing the network, the connectivity level was significantly improved. Although interaction strength between different patches va-ried greatly, the corridors between patches with large interaction were very important. The research could provide scientific reference and basis for nature protection and planning in Fujian Province.

In this paper, we took the leaves of shrubland plants in rocky desertification area in Southwestern Hunan as the research object to analyze the nitrogen (N) and phosphorus (P) stoichiometry characteristics for different functional groups and different grades of rocky desertification, i.e., light rocky desertification (LRD), moderate rocky desertification (MRD) and intense rocky desertification (IRD). The results showed that the average contents of N and P were 12.89 and 1.19 g·kg -1 , respectively, and N/P was 11.24 in common shrubland plants in the study area, which indicated that the growth of most plants were mainly limited by N. The content of N was declined in order of deciduous shrubs > evergreen shrubs > annual herbs > perennial herbs. The content of P and N/P were higher in deciduous shrubs than in perennial herbs. Significant differences were found among the main families of plants in terms of the contents of N, P and N/P in the study sites. The plants of Gramineae had the lowest contents of N and P, andtheir growth was mostly restricted by N, while Leguminosae had the highest content of N and N/P, and their productivity was majorly controlled by P. The contents of N and P in the leaves were significantly higher in dicotyledon plants and C3 plants than in monocotyledon plants and C4 plants, but the N/P was not significantly diffe-rent between these two plant categories. The nitrogen-fixing plants had higher content of N and N/P than the non-nitrogen-fixing plants, but the P content was not significantly different between these two plant groups. There were significant correlations between contents of N and P, N/P and N in all study plots. No significant correlation was found between N/P and P content in the examined rocky desertification sites, except for that in MRD. There were no significant differences of the contents of N, P and N/P under different grades of rocky desertification.

Study of impacts of land uses on spatiotemporal dynamics of soil water content (SWC) is of great significance for understanding the performance characteristics of regional water cycling under changing environment. Based on long-term located field observations, this paper explored the temporal dynamics of soil water in 0-15 m soil profile under four land use types on the Loess Tableland from September 2012 to December 2015. Results showed that the annually averaged SWCs over the 0-15 m soil profile for alfalfa field, fallow field, fertilized cropland and unfertilized cropland were 15.1%, 22.0%, 19.6% and 21.1%, respectively. Soil water contents along the shallow soil profile exhibited seasonal and annual wetting and drying cycle from March to June and July to October, and the profile depths were 0-2, 0-4.6, 0-3 and 0-4.2 m, respectively. Soil water contents along the deep soil profiles had better temporal stability and were influenced by land-use types. Du-ring the observation years, the yield and water consumption in alfalfa field increased, which caused the increase of deep soil desiccation, the 2-10 m soil profile had become stable dry layer, blocking the way of precipitation recharge.As for the soil water balance in other three land use types, it was negative in cropland and fallow field during winter wheat growing season, however, during spring maize growing season, it was negative in fertilized cropland but positive in unfertilized cropland and fallow field. During the fallow period, it was positive in the three land use types. The crop water use efficiency in the fertilized cropland was increased by more than 3 times than the unfertilized cropland.