Application of CITYgreen5.0 model to tender appraisement of small-scale green-space designs

Developed by the American Forests, CITYgreen5.0 model has been widely applied to urban forestry research and has played an important role in analyzing quantitatively the ecological benefits produced by varied green-space ecosystems. One of the functions of this model is to evaluate quickly and objectively on parts of the ecological benefits possibly produced by different design schemes for the same small-scale green-space project before the establishment. A comparative analysis was conducted by modeling partial ecological benefits potentially produced by green-spaces of two different design schemes for the same roof garden of Chuangfushidai-Junjingyuan in Shenzhen, given the growth status of plants both immediately after the establishment and 20 years later. Meanwhile, the project costs for each design scheme were also taken into consideration. The results showed that scheme II, mainly designed with a natural style of plant disposition, had a better greenery structure than that of scheme I, which was basically designed with a regular style of plant disposition. The estimated value of the partial ecological benefits produced by scheme II was larger than that of scheme I and the benefit-cost ratio of scheme II was more rational. It was suggested that scheme II be put into practice.     

Modulation of leaf conductance by root to shoot signaling under water stress in Arabidopsis

Signal communication between root and shoot plays a crucial role in plant resistance to water stress. While many studies on root to shoot signals have been carried out in many plant species, no information is available for the model plant, Arabidopsis, whose adoption has great significance for further probing the molecular aspects of long distance stress signals. Here, we introduced the establishment of techniques for investigations of root to shoot signals in Arabidopsis. Stomatal movements in relation to root signals were probed by using these techniques. The results show that Arabidopsis is a suitable plant species for partial roots drying (PRD) experiments. In the PRD system, while no significant differences were found in leaf water potential between well-watered and stressed plants, water stress led to a decrease in leaf conductance, which suggests a regulation of stomatal movements by root to shoot signals. While water stress caused a significant increase in the concentration of sap abscisic acid (ABA) of xylem, no increase in xylem sap pH was observed. Moreover, the increase in the ABA content of xylem coincided with the decrease in leaf conductance, which suggests a possible role of ABA in the regulation of stomatal movements. Infrared temperature images showed that leaf temperatures of PRD plant were higher compared with those of well-watered plants, which further indicates that stomatal movements can be modulated by root signals. The confirmation of root to shoot signaling in Arabidopsis has established a basis for further investigation into the molecular mechanisms of the root to shoot signaling under water stress.     

Temperature-induced hormesis in plants

Environmental change attracts particular attention by biologists concerned with the performance of biological systems under stress. To investigate these, dose–response relationships should be clarified. It was previously assumed that the fundamental nature of biological dose–responses follows a linear model, either with no threshold or with a threshold below which no effects are expected to occur in biological endpoints. However, substantial literature, including widespread documentation in plants, has revealed that hormesis commonly occurs. Hormesis is highly generalized and can be utilized as a quantitative measure of biological plasticity. Conditioning induced by adaptive responses also occurs in the framework of hormesis and is of particular importance to environmental change biology with regards to evolutionary adaptations.This paper presents additional evidence for hormetic dose responses induced by temperature in plants. The current understanding on hormesis provides a perspective for next generation environmental change research. Hormesis should have a central role in environmental change biology of vegetation.     

Review on Factors Affecting Plant Competition

The competition refers to the interactions of two or more individuals which compete for resources,and is a key process of plant populations and communities.A comprehensive understanding of plant competition is necessary to predict the responses of ecological systems to environmental changes.The inside factors affecting competition include plant density,biological factors and the biomass.The environmental factors related to competition include light,soil moisture,soil nutrient and altitude.High density affects plant competition by controlling plant growth.Allelochemicals produced by plants directly affect their neighbors. Trees and grasses may compete for resources where their root systems overlap.Herbivorous animals chose to eat some plants,resulting in reduction of competition ability of the plants.Plants make morphological shifts and alter the competitive ability between above-ground and below-ground parts in response to the environmental changes.When shade- tolerant species are absent in mixed forest,less shade tolerant species could maintain their dominance for a long period.In contrast,mixed forest with tolerant species would reduce the dominance of less-tolerant species,maintain and probably increase the dominance through the decline of less-tolerant species.Smaller plants should have longer survival time due to their smaller total water requirements when water is scarce,and the longer survival of plants with higher root allocation could be due to a relative reduction in transpiring surface per unit root length.In nutrient-deficient soils,plants are stressed directly by the lack of adequate nutrients and competitive interactions may be controlled by a plant’s ability to efficiently take up available nutrients.In nutrient-sufficient soils,plants with the highest maximum growth rates may well be the superior competitors.Intensity of light competition declines with altitude.The future research about competition will focus on large scale,long term and multi-population research,the multi-disciplinary cooperat     

Quantity of plant leaf area on three major public squares in Kunming City,China

Regressive formulae to calculate the quantity of plant leaf area for 13 species of ornamental plants were set up based on investigation data of 30 species on 3 major public squares (Dongfeng square, Shengli square and Guandu square) in Kunruing City, China, which were applied to calculate quantities of plant leaf area of these 13 species. The quantities of plant leaf area for the other 17 ornamental plant species on these squares were directly measured, and the total quantity of plant leaf area of each studied square was obtained individually. The results showed that the quantity of plant leaf area on Shengli square with ornamental plants structure composed of arbor tree species, shrub tree species and turf grass was highest among the three squares. It is believed that the design model of multi-storied vertical structure and proper tending of plant community could not only increase the quantity of plant leaf area, but also play an important role in generating ecological and landscaping benefits.Some corresponding suggestions were put forward on the basis of comprehensive analyses on the plant leaf area quantity of the three representative squares in Kunming urban area.     

Impact of urbanization on plant diversity: A case study in built-up areas of Beijing

Urbanization is developing rapidly in the world, which seriously changes the habitat of organisms and has clearly a negative effect on biodiversity. Preservation of biodiversity is crucial in urban planning and management, which is also an important symbol for the level of greening. Problems such as scarcity of urban green space and plant species have become obstacles to the establishment of ecological friendly cities. However, coexistence of nature and modernization, as well the coordination of economic development and biodiversity, are goals that people are seeking. We have taken the builtup areas of Beijing as a study case and discussed the impacts of urbanization on plant diversity, with the support of fieldwork and SPOT remote sensing data. The results are as follows： 1） in the process of urbanization, exotic plants have been widely introduced, which has affected species composition and the proportion of native plants; it is clear that artificial green spaces always will have a lower level of plant diversity than natural green spaces; 2） functional differences of green space types partially decide their species abundance, so that plant diversity in greenbelts and streets is generally lower than in parks; 3） the spatial variety of plant diversity contributes much to the imbalance of district de- velopment and the planning of different functional zones; this variation is embodied in different ring-belts and directions; 4） habitat fragmentation also affects plant diversity to a great extent; there is a significant positive correlation between high fragmentation and low plant diversity. According our results, some suggestions are proposed, which would be suitable for the preservation of plant di- versity and ecological improvement during urbanization.     

Effect of livestock grazing and human uses on herbaceous species diversity in oriental beech （Fagus orientalis Lipsky） forests,Guilan, Masal,northern Iran

Plant diversity plays key ecological roles in forest ecosystems, including influencing succession, resilience and nutrient cycling. This study was conducted to investigate the effect of livestock grazing and human uses on herbaceous species diversity. We surveyed 50 ha of protected area and 50 ha of unprotected area to evaluate herbaceous species diversity in oriental beech （Fagus orientalis Lipsky） forests in northern Iran. We calculated and compared three indices each of diversity and evenness, and species richness between the two areas. Herbaceous cover was higher in the unprotected area while leaf litter depth and tree canopy cover were higher in the protected area. The diversity indices, H （Shan- non-Wiener index ）, N~ （McArthur index）, N2 （Hill＇s index）, EQ （Modified Nee index）, E,ar （Smith-Wilson index）, E5 （modified index of Hill） and R=S （species richness） and species richness R=S were greater in the protected area than in the unprotected area, suggesting that protection from grazing results in increased numbers of plants and species. The effect of land protection on plant diversity was more pronounced for evenness than for species richness and the positive correlation between diversity and evenness indices was higher than that between diversity and richness.     

Evaluation method of the ecological benefits of urban green spaces and application conditions

The importance of ecological benefit analyses about green space systems has been widely discussed on the basis of a per-ceived bias towards the landscaping effect of green spaces to be built in urban areas as opposed to the perception of comprehensive ecological benefits of designed plant communities. Given the basic principle of ecological benefit analyses and evaluation methods widely applied today, the methodology to calculate ecological benefits and to model the expansion of urban green spaces by CITY-green 5.0 and its conditions for application were explored. We propose that aerial images can be substituted by AutoCAD graphics of a green space containing detailed information of plant dispositions by digitizing the key features during the working process in order to evaluate the ecological benefits quickly and to offer proper guidance to the establishment of small scale green spaces in urban areas. The theoretical foundation, potential application range and prospects for extension of the method are introduced by using the analysis of ecological benefits of the green spaces on the campus of Southwest Forestry College, Kunming, as an example.     

Distribution of Malpighia mexicana in Mexico and its implications for Barranca del Río Santiago

Wild plants represent relatively unexplored resource of high economic potential, especially as an alternative to developing new crops and, even more relevant, for improving existing crops and contributing to nutrition and health. The wild species M alpighia mexicana(manzanita) has a wide tradition of food, medicinal and ornamental use in Mexico. It is part of the American-origin group of tropical shrubs that produce edible red fruits, such as A cerola, which is considered the most important natural source of vitamin C in the world. Given the role played by M. mexicana in Mexico, and particularly in Barranca del Río Santiago(Santiago River Canyon), we modelled its potential distribution in both geographical areas. We used species' records from databases, local herbaria and records collected by the authors as well as climatic variables representing long term average, variability and extreme conditions of temperature and precipitation. To fit the models we used the modelling algorithm Maxent and selected an adequate configuration by testing a range of model complexity settings. The results indicate a clear species preference for warm-dry tropical forest, most extensively in the Balsas river depression and the central valleys of Oaxaca. The probability of the species presence in the western region was also high, although the probability was also high for smaller surface areas, such as the region of Santiago river canyons, which are covered by warm-dry tropical forests.     

Dendrochronology and climatic signals in the wood of Nectandra oppositifolia from a dense rain forest in southern Brazil

Nectandra is one of the most representative genera of Lauraceae in the subtropical Atlantic Forest of Brazil. The objective of this work was to study the dendrochronological potential of Nectandra oppositifolia Nees and Mart. from two sites in Santa Catarina State in southern Brazil. A tree-ring chronology of 34 trees was developed. The time span ranged from 1843 to 2013. The oldest and youngest trees were 171 and 47 years-old and the average length of the series was 103 years. Average diameter and annual increment were 20.64 cm and0.74 mm a-1; diameter and age were unrelated. The species has good dendrochronological potential with an intercorrelation of 0.61 between sites, indicating the existence of a synchronous pattern in the development of the trees. The climate response of the species could be seen by negative tree growth effects for previous hot and current rainy growth seasons.     

Ethno-medicinal plants used by Bengali communities in Tripura,northeast India

Northeastern India has high medicinal plant diversity due to variance in topography and physiognomy. We documented the uses of various medicinal plants by the Bengali people of West district and South district of Tripura state for their own health care as well as for domesti-cated animals. Based on semi structured interviews, group discussions and information from local informants, a total of 93 species of medicinal plants of 52 families and 83 genera were documented. These plants were used to treat more than 55 different human diseases and 6 diseases of livestock. Sixty-eight plant species were used singly and the rest were used in combination with other species for therapeutic formulations of various diseases. Leaves of plants were most often used for most of the ethnobotanical preparations. Maximum consensus value of 96% was recorded for Chromolaena odorata （L.） King ＆amp;H. Rob., and the mini-mum was 15%for Bambusa balcooa Robx. Of the 93 plant species, 75 species showed pharmacological properties. Prospects for augmenting existing knowledge and enhancing the use of traditional medicinal plants are discussed.     

The diversity of arbuscular mycorrhizal fungi of Rosa acicularis ’Luhe’ in saline areas

Arbuscular mycorrhizal fungi(AMF)in the soil encompass a diversity of species and play an important role in maintaining ecosystem balance.However,little research has focused on the AMF diversity of Rosa acicularis Lindl.’Luhe’,which has been cultivated in northeastern saline areas,because of its strong salt tolerance and cold resistance.In the present study the AMF in the rhizosphere of R.acicularis Luhe were identified and AMF diversity and community composition were assessed using morphological and molecular techniques.Vesicles,hyphae,and arbuscular structures were observed in seedlings of different ages.Result shows that AMF established a good symbiotic relationship with R.acicularis Luhe.The colonization rate and spore density tended to increase over time.The AMF diversity in the rhizosphere of R.acicularis Luhe was low and four species of AMF were validated:Rhizophagus irregularis,Glomus aggregatum,Septoglomus furcatum,and Funneliformis mosseae.Of these,R.irregularis and G.aggregatum were dominant and have high salt tolerance.Determining the AMF diversity in the rhizosphere of R.acicularis Luhe will aid in screening AMF species with strong resistance and using mycorrhizas for plant establishment in breeding programs.     

Decomposition and nutrient release patterns of Phyllostachys bambusoides and Arundinaria racemosa, India

We investigated decomposition and nutrient release patterns of leaf and sheath litter of two important highland bamboo species (viz. Phyllostachys bambusoides Sieb. (Zucc.) and Arundinaria racemosa Munro) by using a litter bag technique. Our objective was to improve understanding of the addition of organic matter and nutrients to soil from the litter of two abundant highland bamboo species, species that support the local population of the region in many ways. N concentration and N/P ratio were significantly higher (p<0.01) in leaf litter of P. bambusoides. Significantly, larger values of lignin concentration, C/N ratio, and lignin/N ratio were found in the sheath litter of A racemosa. Weight loss of both leaf and sheath litter was strongly positively correlated with N and N/P ratio, and significantly negatively correlated (p<0.01) with C/N ratio. Lignin/N had a negative correlation with decay rate. In both species, only lignin concentration of the litter showed strong positive correlation with N release. Litter decomposition and N release patterns were similar for the two bamboo species, whereas, P release rate from leaf litter was higher in P. bambusoides and differed significantly between sheath and leaf litter for both species. The complex pattern of nutrient release through mineralization and immobilization during litter decomposition ensures nutrient availability in both managed and natural bamboo stands subjected to anthropogenic disturbances.     

Transcriptome and degradome sequencing reveals changes in Populus × euramericana 'Neva' caused by its allelopathic response to p-hydroxybenzoic acid

Plant species produce different types of allelopathic chemicals in nature;however,little is known about the differential regulation of plant allelopathy.Because allelopathy caused by p-hydroxybenzoic acid(pHBA) is one of the main obstacles to continuous cropping of Populus × euramericana 'Neva',we examined gene expression dynamics in Neva leaves induced by pHBA.The expression of genes related to photosynthesis and respiration changed,while mRNA involved in regulating gene expression during allelopathy was degraded.Some miRNAs that are involved in plant allelopathy target crucial genes for regulating reactive oxygen species.Moreover,coexpression regulatory networks were constructed based on profiles of the identified miRNA-target interactions and the differentially expressed miRNA-target pairs.These findings provide a mechanistic framework for understanding allelopathy in plants.     

Changes induced by osmotic stress in the morphology,biochemistry, physiology,anatomy and stomatal parameters of almond species （Prunus L. spp.） grown in vitro

We investigated the influence of different levels of osmotic stress on growth and development in selected wild almond species(eight Prunus spp.) grown in vitro. The study, while endorsing the efficacy of in vitro screening of auxiliary buds of wild almond for osmotic stress tolerance, showed species variability in its response to osmotic stress. Osmotic stress reduced growth and development of all the species. However, the putative tolerant Prunus spp. showed better performance than the putative susceptible genotypes. On average there was an 80% decrease in shoot dry weight at-1.2 MPa. Reduction in shoot weight was more common in osmotic stress-susceptible species in the section labeled ‘Euamygdalus'. The tolerant Prunus species produced smaller changes in biochemical responses than the sensitive cultivars for malondialdehyde content, catalase activity, relative permeability of protoplast membranes, and net photosynthetic rate. The tolerant species maintained cell integrity better than drought sensitive species. Wild almond species in the section labeled ‘Spartioides'(Prunus arabica(Olivier) Neikle, Prunus glauca (Browicz) A.E. Murray, Prunus scoparia Spach) and ‘Lycioides'(Prunus lycioides Spach, Prunus reuteri Bossi. et Bushe) were best adapted to osmotic stress. Increase in chlorophyll concentration and leaf thickness under high osmotic stress can be considered as preliminary selection parameters for osmotic stress tolerance in Prunus spp. The study confirmed the efficacy of the in vitro method for screening of large number of genotypes for osmotic stress tolerance in wild almond species.     

Characteristics of soil seed bank in plantation forest in the rocky mountain region of Beijing, China

We investigated characteristics (scales and composition) of soil seed banks at eight study sites in the rocky mountain region of Beijing by seed identification and germination monitoring. We also surveyed the vegetation communities at the eight study sites to explore the role of soil seed banks in vegetation restoration. The storage capacity of soil seed banks at the eight sites ranked from 766.26 to 2461.92 seeds·m -2 . A total of 23 plant species were found in soil seed banks, of which 63 80% of seeds were herbs in various soil layers and 60% of seeds were located in the soil layer at 0 5cm depth. Biodiversity indices indicated clear differences in species diversity of soil seed banks among different plant communities. The species composition of aboveground vegetation showed low similarity with that based on soil seed banks. In the above- ground plant community, the afforestation tree species showed high importance values. The plant species originating from soil seed banks represented natural regeneration, which also showed relatively high importance values. This study suggests that in the rocky mountain region of Beijing the soil seed banks played a key role in the transformation from pure plantation forest to near-natural forest, promoting natural ecological processes, and the role of the seed banks in vegetation restoration was important to the improvement of ecological restoration methods.     

Osmoregulation mechanism of drought stress and genetic engineering strategies for improving drought resistance in plants

Drought, one of the main adverse environmental factors, obviously affected plant growth and development. Many adaptive strategies have been developed in plants for coping with drought or water stress, among which osmoregulation is one of the important factors of plant drought tolerance. Many substances play important roles in plant osmoregulation for drought resistance, including proline, glycine betaine, Lea proteins and soluble sugars such as levan, trehalose, sucrose, etc. The osmoregulation mechanism and the genetic engineering of plant drought-tolerance are reviewed in this paper.     

Floristic composition and ecological gradient analyses of the Liakot Forests in the Kalam region of District Swat,Pakistan

Kalam Kohistan is a dry,temperate hilly region in the Hindu Raj Series of the Greater Hindu Kush Mountains with diverse forests.As plant distribution and composition is expression of a range of various environmental variables,ecological and floristic attributes of vegetation in the Laikot Forests were therefore evaluated via consecutive explorative trips.These forests have not been evaluated ecologically before due to harsh climatic conditions and issues of accessibility and the study in hand is one of the first in its nature.Quantitative ecological techniques were used to sample forest vegetation and identify species in quadrats of 2 m×2 m for herbs,5 m×5 m for shrubs and 10 m×10 m for trees.All the data of 195 plant species and environmental factors were analyzed via Two-way Cluster Analysis and Canonical Correspondence Analysis using PCORD and CANOCO software.Among 195 plant species from 63 families were 27 species of Asteraceae,the most-speciose family,followed by Poaceae(20 spp.).The dominant life form was therophyte(86 spp.;44%share),followed by phanerophyte(41 spp.;21%share).For the leaf size spectrum,most prevalent was nanophyll(73 spp.;44%)followed by microphyll(66 spp.,34%)and mesophyll(44 spp.;23%).Calcium carbonate,pH,potassium,sand,silt,organic matter,slope aspect and grazing significantly influenced species composition,distribution and habitat.The floristic variation in the region was diverse due to elevational and aspect gradients and thus devided into three zones.This vegetation zonation can be utilized for forest management,species and habitat conservation.Both in situ and ex situ conservation of threatened plant species may improve their conservation status in future if address properly.