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西藏色季拉山杜鹃花种质资源的初步研究 总被引：5，自引：0，他引：5
色季拉山杜鹃花有２５个种及变种，其中７种分布于东坡，３种分布于西坡，４种分布于山顶地带，１１种在东西坡均有分布。其生境类型可分为林缘灌丛型、森林型、高山灌丛型３类，以森林型种类居多，占４８％。其观赏类群可分为香花类、团花类、雅致类和黄花类４群，以香花类和黄花类观赏价值最高，雅致类最易被驯化利用。 相似文献
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报春花,以它的迎风傲雪向人们传递春天到来的信息,所以被人们比作春天的信使。报春花属报春花科,全世界有约500余种,我国就有300余种。国产报春花栽培历史悠久,已成为早春的主要盆栽植物。作为观赏花卉,按其生境,可分为林内阴湿型、疏林透光型、林缘草甸型和高山冷湿型等类型。当今,国产报春花属植物的流行种类有如下各种： 相似文献
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<正>四季海棠为秋海棠科秋海棠属,原产巴西,又称秋海棠、虎耳海棠、瓜子海棠。四季海棠是多年生常绿草本花卉,东北地区一般作为一年生露地栽培,在园林绿化上将其应用于花坛布置,效果极佳,目前已成为最主要的花坛花卉之一,具有株型圆整、花多而密集、极易与其它花坛植物配植、观赏期长等优点,因而越来越受到欢迎。1品种筛选四季秋海棠的叶片,可分成两大种类,其一为接受日照后变成红绿色,另一则为红铜色。花色有红、桃红、粉 相似文献
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‘昆明鸟’秋海棠系由大王秋海棠和掌叶秋海棠杂交F1选育而成，常有多节短茎，叶浅型、被浅白斑，直立性较强，抗倒伏，抗白粉病，具较高的观赏价值。‘康儿’秋海棠由大王秋海棠和长翅秋海棠杂交F1选育而成，常用1－3节花茎，叶大型、浅裂，长势旺盛，抗白粉病极强，适宜栽培观赏。‘白雪’秋海棠为野外发现的自然杂交新品种，通过研究证实其为变色秋海棠和掌叶秋海棠的杂交F1代个体，为根茎类秋海棠，无地上茎或地上茎不明显，叶片中型、被毛、浅裂且密被白色斑点，十分美丽，对白粉病有较强的抗性。 相似文献
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‘昆明鸟’秋海棠系由大王秋海棠和掌叶秋海棠杂交F1 选育而成, 常有多节短茎, 叶浅裂、被浅白斑, 直立性较强, 抗倒伏, 抗白粉病, 具较高的观赏价值。‘康儿’秋海棠由大王秋海棠和长翅秋海棠杂交F1 选育而成, 常有1～3 节花茎, 叶大型、浅裂, 长势旺盛, 抗白粉病极强, 适宜栽培观赏。‘白雪’秋海棠为野外发现的自然杂交新品种, 通过研究证实其为变色秋海棠和掌叶秋海棠的杂交F1 代个体, 为根茎类秋海棠, 无地上茎或地上茎不明显, 叶片中型、被毛、浅裂且密被白色斑点, 十分美丽, 对白粉病有较强的抗性。 相似文献
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三种室内观叶植物光合特性与抗SO2能力研究 总被引：5，自引：0，他引：5
对常春藤、鸭跖草和棕榈３种适于室内栽培的观叶植物光合特性和抗ＳＯ２能力进行研究,结果显示：棕榈光饱和点、光补偿点较高,属半阴性至半阳性植物,在室内较明亮处有光合积累;常春藤、鸭跖草光饱和点和光补偿点均低,属阴性植物,宜于室内环境栽培。对ＳＯ２抗性以棕榈最强,鸭跖草最弱。常春藤具抗ＳＯ２和阴生性特点,适于光能资源不足地区和ＳＯ２污染地区室内栽培利用。 相似文献
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Shade factors, defined as the percentage of sky covered by foliage and branches within the perimeter of individual tree crowns, have been used to model the effects of trees on air pollutant uptake, building energy use and rainfall interception. For the past 30 years the primary source of shade factors was a database containing values from 47 species. In most cases, values were obtained from measurements on a single tree in one location. To expand this database 11,024 shade factors were obtained for 149 urban tree species through a photometric process applied to the predominant species in 17 U.S. cities. Two digital images were taken of each tree, crowns were isolated, silhouette area defined and shade factors calculated as the ratio of shaded (i.e., foliage and woody material) pixels to total pixels within the crown silhouette area. The highly nonlinear relationship between both age and diameter at breast height (DBH), and shade factor was captured using generalized additive mixed models.We found that shade factors increased with age until trees reached about 20 years or 30 cm DBH. Using a single shade factor from a mature tree for a young tree can overestimate actual crown density. Also, in many cases, shade factors were found to vary considerably for the same species growing in different climate zones. We provide a set of tables that contain the necessary values to compute shade factors from DBH or age with species and climate effects accounted for. This new information expands the scope of urban species with measured shade factors and allows researchers and urban foresters to more accurately predict their values across time and space. 相似文献
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Determining how suburbanization shapes tree-species composition and diversity is vital in Canadian and most nations’ cities, as suburban and peri-urban areas continue to grow faster than any other region. These areas, characterized by various land types and uses, represent differences in management and governance, jurisdiction, planting practices and species selection, and professional and political agendas. Such complexities emphasize the importance of exploring the influence of various environmental and location attributes of suburban neighbourhoods. Using hierarchical cluster analysis to classify urban forest species assemblages, we found that location attributes such as land type, development decade, and geography are influential on species composition and diversity − but only to an extent. We found that street-tree assemblages were classified more distinctly than remnant woodlands, which were in turn more distinct than tree communities found on residential properties. Residential land types had a high degree of species heterogeneity, highlighting the importance of not only considering the location attributes chosen for this study, but also including socioeconomic and cultural variables in future ecological classification schemes. Identifying drivers of species composition and diversity is useful for developing and implementing forest management strategies for urban and peri-urban areas, as different species assemblages give rise to different challenges and management opportunities, as well as varying quantities of ecosystem services, values, and benefits. 相似文献
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研究了宿根性阔叶补血草（ＬｉｍｏｎｉｕｍｌａｔｉｆｏｌｉｕｍＯ．Ｋｕｎｔｚｅ）和里海补血草（Ｌ．ｃａｓｐｉｕｍＧｏｕａｎ）各植株间花粉和柱头的异型性，采用异型授粉方法进行种间杂交，克服了同型杂交不孕的困难，获得了种间杂种。通过染色体组型分析确认了杂种的真实性。入选的里海补血草×阔叶补血草杂种Ｆ１４号株性状优良，可通过组培繁殖形成无性系，作为补血草新类型推广。试验也为我国补血草野生资源的开发利用提供杂交育种技术参考 相似文献
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Jess K. Zimmerman Liza S. Comita Jill Thompson María Uriarte Nicholas Brokaw 《Landscape Ecology》2010,25(7):1099-1111
Where large disturbances do not cause landscape-wide mortality and successional change, forested ecosystems should exhibit
landscape metastability (landscape equilibrium) at a scale equal to the dominant patch size of disturbance and recovery within
the landscape. We investigated this in a 16-ha contiguous plot of subtropical wet forest in Puerto Rico, the Luquillo Forest
Dynamics Plot (LFDP), which experienced two major hurricanes during the 15-year study and has a land use history (logging
and agriculture 40 or more years hence) that differs in intensity between two areas of the plot. Using he LFDP as our “landscape,”
we studied the spatial pattern of community change through time (3–5 year intervals) by calculating community dissimilarity
between tree censuses for two size classes of trees (1 to <10 cm DBH and ≥10 cm DBH) in quadrats ranging in size from 0.010–1 ha
and for the entire landscape, i.e., plot or land use type. The point at which the decline in community dissimilarity with
quadrat size showed maximum curvature identified the dominant patch size (i.e., point of metastability). For canopy trees
≥10 cm dbh, there was no evidence that the community experienced landscape-wide successional changes in either land use type,
and we found a consistent patch size of community change around 0.1 ha (range 0.091–0.107). For the understory tree and shrub
community (1 to <10 cm dbh) there was some evidence of landscape-wide community changes over time in response to hurricane
damage, apparently driven by interactions with the dominant canopy species, whose composition varied with land use intensity,
and their species-specific susceptibility to hurricane damage. 相似文献
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Two studies were conducted on a third-story rooftop to quantify the effect of solar radiation (full sun versus full shade) on several US native and non-native species for potential use on extensive green roofs. In the first study, plugs of six native and three non-native species were planted in May 2005 on substrates of two different depths (8.0 and 12.0 cm) both in sun and shade. Absolute cover (AC) was recorded using a point-frame transect during the growing season beginning in June 2005 and every 2 weeks thereafter for a period of 4 years. By week 174 (23 September 2008), most species exhibited different AC within a depth between sun and shade. However, when all species were combined, overall AC did not differ between sun and shade within a depth. This indicated that while species make-up was changing among solar radiation levels, that overall coverage was not significantly different between sun and shade. For all substrate depths and solar levels, the most abundant species were Sedum acre, Allium cernuum, Sedum album ‘Coral Carpet’, and Talinum calycinum. Less abundant species included Talinum parviflorum, Carex flacca, Sedum stenopetalum, and Sedum divergens, which all exhibited 0 or near 0 AC regardless of depth or solar radiation levels. With the exception of T. calycinum, native species were less abundant than non-native species.In the second study, six common extensive green roof species of Sedum established from seed in May 2005 on a 10.0 cm (3.9 in) substrate depth were compared in both sun and shade over four growing seasons. AC was evaluated as in the previous study. Solar radiation did not affect AC, but overall species composition differed between sun and shade levels. The most abundant species in full sun were S. acre (0.57 AC) and S. album ‘Coral Carpet’ (0.51 AC). Sedum kamtschaticum (0.57 AC) and Sedum spurium ‘Coccineum’ (0.35 AC) performed the best in the shade. For both solar levels, the least abundant species at week 174 were Sedum pulchellum (0.0 AC) and S. album ‘Coral Carpet’ (0.1 AC). 相似文献
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Small-scale effects of historical land use and topography on post-cultural tree species composition in an Alpine valley in southern Switzerland 总被引：1，自引：0，他引：1
Investigations of spatial patterns in forest tree species composition are essential in the understanding of landscape dynamics,
especially in areas of land-use change. The specific environmental factors controlling the present patterns, however, vary
with the scale of observation. In this study we estimated abundance of adult trees and tree regeneration in a Southern Alpine
valley in Ticino, Switzerland. We hypothesized that, at the present scale, spatial pattern of post-cultural tree species does
not primarily depend on topographic features but responds instead to small-scale variation in historical land use. We used
multivariate regression trees to relate species abundances to environmental variables. Species matrices were comprised of
single tree species abundance as well as species groups. Groups were formed according to common ecological species requirements
with respect to shade tolerance, soil moisture and soil nutrients. Though species variance could only be partially explained,
a clear ranking in the relative importance of environmental variables emerged. Tree basal area of formerly cultivated Castanea sativa (Mill.) was the most important factor accounting for up to 50% of species’ variation. Influence of topographic attributes
was minor, restricted to profile curvature, and partly contradictory in response. Our results suggest the importance of biotic
factors and soil properties for small-scale variation in tree species composition and need for further investigations in the
study area on the ecological requirements of tree species in the early growing stage. 相似文献
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2006－2007年,对甘肃省酒泉、定西、天水等地9个花卉制种繁育、示范生产基地种植的旱金莲、唐菖蒲、孔雀草、万寿菊、波斯菊、大丽花等56种花卉根际线虫类群进行了研究。经鉴定111076条线虫分属43个属,4个营养类群（食细菌、食真菌、杂食/捕食和植物寄生线虫）,其中有益的非植物线虫属32个,有害的植物线虫属11个,占总调查属数量的1/4,相对比例较大,特别是垫刃属（Tylenchus）和 丝尾垫刃属（Filenchus）的线虫出现的频率较高,涉及花卉51种和42种,分别占调查花卉总数的91％和75％。本研究结果将为进一步分析甘肃省各种花卉根际线虫的潜在风险提供参考数据,为甘肃省花卉进出口贸易的线虫争端提供谈判和决策依据。 相似文献
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We explored patterns of plant species richness at different spatialscales in 14 habitats in a Swedish rural landscape. Effects of physicalconditions, and relationships between species richness and management historyreaching back to the 17th century were examined, using old cadastralmaps andaerial photographs. The most species-rich habitats were dry open semi-naturalgrasslands, midfield islets and road verges. Alpha diversity (species richnesswithin sites) was highest in habitats on dry substrates (excluding bedrock withsparse pines) and beta diversity (species richness among sites) was highest inmoist to wet habitats. Alpha and beta components of species richness tended tobe inversely related among habitats with similar species richness. Managementhistory influenced diversity patterns. Areas managed as grasslands in the17th and 18th century harboured more species than areasoutside the villages. We also found significant relationships between speciesrichness and soil type. Silt proved to be the most species-rich topsoil(10–20 cm) in addition to thin soils top of on green- orlimestone bedrock. The variation in species richness due to local relief orform of thesite also showed significant relationships, where flat surfaces had the highestnumber of species. In contrast, no significant relationship was found betweenspecies richness and aspect. Our study suggests that present-day diversitypatterns are much influenced by management history, and that small habitat,e.g., road verges and midfield islets, are important for maintaining speciesrichness.This revised version was published online in May 2005 with corrections to the Cover Date. 相似文献
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百合属植物种子发芽试验研究 总被引：1，自引：0，他引：1
对8种百合属植物的种子性状和发芽特性进行了试验研究.结果表明,仅毛百合属于地下子叶类型,朝鲜百合、垂花百合、有斑百合、大花卷丹、细叶百合、麝香百合杂种系品种罗瑞拉、亚洲百合杂种系品种布鲁拉诺均属于地上子叶类型.有斑百合、大花卷丹、朝鲜百合、细叶百合、罗瑞拉和布鲁拉诺种子发芽率高,其中罗瑞拉发芽率最高,达91%.毛百合和垂花百合种子发芽率低,低于20%,其中毛百合发芽率仅8.8%.有斑百合种子储藏2 a后其发芽率仍较高,可高达92%. 相似文献