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Hedychiums are multipurpose plants cultivated as ornamentals because of their multicolor and showy and scented flowers and as medicinal plants because of their essential oils that have been found to possess antimicrobial and insecticidal properties. There is often taxonomic and botanical confusion about Hedychium species and cultivars because of the apparent existence of more than one cytotype within several Hedychium species, most likely because of the ease with which these species hybridize. Nuclear DNA content (2C-DNA) was determined for the first time in 23 Hedychium species and hybrids. The 2C-values ranged from 1.70 pg to 3.98 pg. We also determined the chromosome number of one species, Hedychium stenopetalum, which was found to be diploid (2n = 2x = 34), supporting the widely held view that the basic chromosome number in Hedychium is x = 17, and the existence of different cytotypes is most probably attributable to natural hybridization. Our results should be helpful not only in clarifying the botanical and taxonomic confusion in Hedychium but also in paving the way for a sound breeding program for this increasingly important ornamental ginger.  相似文献   
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Toxicological observations indicate that pulegone-1,2-epoxide, isolated from the medicinal plant, poleo (Lippia stoechadifolia), is an insect neurotoxin. These observations prompted studies of the action of pulegone-1,2-epoxide on acetylcholinesterase activity. Kinetic analyses of the hydrolysis of acetylthiocholine by eel acetylcholinesterase in the presence of pulegone-1,2-epoxide shows an irreversible inhibition of the enzyme in a manner similar to that shown for carbamates. Five other monoterpenoids were similarly tested for their effects on acetylcholinesterase, and comparison of the inhibitions suggests that both the epoxy and keto groups are required for irreversible inhibition. Although pulegone-1,2-epoxide inhibits both house fly and Madagascar roach (Gromphadorhina portentosa) acetylcholinesterases in vitro, no correlation between inhibition of roach acetylcholinesterases in vivo and the onset of symptoms preceding death was shown.  相似文献   
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A review of research and research needs in urban forestry was carried out in Denmark, Estonia, Finland, Latvia, Norway and Sweden during 2005. A questionnaire addressing post-2000 and ongoing research was sent to 146 researchers and generated 76 completed questionnaires. Universities were found to lead urban forestry research, while municipalities headed funding organisations in terms of number of projects funded. Planning, ecological and management aspects were the most common research themes, but socially oriented research also played an important role. The research needs questionnaire was sent to 192 key research actors (assignors, users and researchers), resulting in 63 completed needs assessments. The research themes of ‘urban forest management’, ‘social and cultural values’ and ‘urban forest and green planning’ were prioritised for future research. Comparison of ongoing research and research needs showed discrepancies, as ongoing research does not always cover the same themes identified as primary research needs. Priorities for future research as identified by the research community respective those assigning and using research also differed. Economic assessment of benefits, for example, scored much higher as a need among researchers than other respondents. In terms of present weaknesses in the research ‘infrastructure’, research actors emphasised lack of funding, fragmentation of research and insufficient critical mass. The region's urban forestry research can be enhanced and made more meaningful by strengthening national and international networking within the research community, across disciplines, as well as between researchers and those commissioning and using research.  相似文献   
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The demand for sound scientific information and public participation is particularly great in urban forestry. Urban society's manifold perceptions, preferences and demands for urban forest goods and services need to be considered, indicating the necessity for socially inclusive planning processes. Successful policies can only be formulated by establishing close links with, for example, urban planning and municipal policies. Inherently, this means that close ties between research and policy are required. This article discusses the outcomes of the NeighbourWoods research and development project in which a wide range of tools for public participation were tested in six urban woodland case-studies across Europe. A distinction was made between characteristics of the specific participatory tools and those of the communication process between the facilitators (scientists) of the participation process and the end-users of information (local policy-makers). Public willingness to participate depends on factors such as existing controversy, emotions attached to the forest, and perceived dangers, e.g., in terms of threats to the status quo. Policy makers’ willingness to involve themselves depends on political interests, on prior experience with public participation processes, and on their trust in the facilitators of the public participation process. Findings confirm that a set of tools comprising a step-wise process from informing the public in an attractive way, collecting information on public opinion, towards fully participatory approaches such as direct involvement in decision-making is most likely to ensure socially inclusive planning. Communication with policy-makers requires a high degree of openness, clearly explaining every phase of the process, being open about each other's expectations, in short, by developing relationships based on mutual trust.  相似文献   
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A comprehensive European overview of recent and ongoing research in Europe has been carried out within the framework of COST Action E12 'Urban Forests and Trees', a pan-European research network. This paper presents some of the main findings of a comparative analysis of 20 individual country reports. The analysis shows that research on urban forests and urban trees in Europe has a wide scope and is rather fragmented and uncoordinated. Universities and state research institutes, mostly with a forestry or horticultural background, dominate the research. Relevant research is primarily funded from state and municipal sources. Significant differences exist between countries with regards to the level of activity, research topics and institutions involved.  相似文献   
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