上海地区屋顶绿化植物调查研究

报道了上海地区屋顶绿化植物种类,结果为用于屋顶绿化的植物材料共43科90属.通过调查及分析,屋顶绿化植物在特殊的环境条件下己形成自己的形态特征并具有重要的生态功能.     

轻型屋顶绿化中景天属植物栽培基质配比研究

以国产泥炭、椰糠、珍珠岩、陶粒等为原料,进行不同配比的轻型屋顶绿化栽培基质配方研究,依据其理化性质,筛选出2种较适配方。以金叶佛甲草Sedum lineare ‘Aurea’等5种景天属植物为试材,对2种配比基质中扦插植株的生长效果进行比较,以筛选适于景天属植物屋顶绿化栽培基质。结果表明,除松塔景天S. nicaeense在2种栽培基质上生长差异不显著外,其余4种景天属植物均在配比为国产泥炭∶椰糠∶珍珠岩= 2∶3∶1的基质(F3)中生长旺盛,覆盖迅速,地上及地下部分生物量积累较大。因此,初步确定基质F3为适宜景天属植物生长的轻型屋顶绿化基质。     

绿色屋顶径流调控研究进展

绿色屋顶在屋顶径流调控方面发挥着重要作用,能够有效减少径流量、延缓产流时间、降低径流峰值和改善径流水质.本文从绿色屋顶的分类及界定、绿色屋顶对径流的调控机制、绿色屋顶对径流量和水质的调控作用及其影响因素等方面阐述了国内外的研究现状,并从绿色屋顶植物的选择、高效绿色屋顶构建模式筛选、绿色屋顶径流调控规律研究、绿色屋顶截流能力的价值评估、绿色屋顶径流污染物的源 汇解析及缓解措施等方面提出了绿色屋顶径流调控的研究趋势,以期为城市绿色屋顶的建设提供理论和方法支持.     

8种轻型屋顶绿化植物种间竞争性研究

以8种常见的轻型屋顶绿化植物为试材,在不同厚度基质上采用随机混植模式配置,通过观测植物覆盖度和植被景观变化,分析不同植物种间竞争性。结果表明,松叶牡丹Portulaca grandiflora具有较强的侵占性,在构建多植物混植景观中宜慎用;垂盆草Sedum sarmentosum和黄花景天S.mexicanum具有较强竞争力和抗逆性,随着基质层厚度降低覆盖度占比增大;万点星S.acre和凹叶景天S.emarginatum竞争能力次之,在不同厚度基质层中覆盖度占比差异不大;玉吊钟Kalanchoe fedtschenkoi‘Rosy Dawn’、高景天S.kamtschaticum‘ellacombeanum’和棒槌玉莲S.nussbaumerianum匍匐竞争能力弱,适宜做竖向景观营建。综合考虑植被稳定性和建设成本,营建多样性轻型屋顶绿化植物景观选择基质层厚度10 cm为宜。     

高度城市化地区既有建筑屋顶绿化建设潜力评析——以上海中心城区为例

广泛的屋顶绿化是改善城市生态环境的重要举措。为探求中国高度城市化地区屋顶绿化建设推广的可行途径,综述了国外先进国家的屋顶绿化建设历程以及针对既有建筑的拓展型屋顶绿化的建设难点,并以中国屋顶绿化发展较早的上海为例,对其中心城区（即上海市外环线以内的区域,总面积约667.80km2）既有建筑的屋顶绿化进行了适建性评估。国外屋顶绿化建设领先的国家大多经历了从鼓励到强制、从新建建筑到既有建筑的历程;针对既有建筑的拓展型屋顶绿化的建设更具技术挑战性,必须进行构造创新、基质优化、植物精选和成本控制;上海已率先发布屋顶绿化建设的强制性政策,相关技术研发已有相当基础,但推广建设类型仍有局限,拓展型屋顶绿化极具建设潜力。     

加州科学院——新潮自然博物馆

在美国旧金山的金门公园中,坐落着一座屋顶长满植物,屋顶四周被太阳能电池板环绕的建筑,别致且富有浓郁的现代气息,加州科学院（以下简称为科学院）就位于其中。虽然这座新潮的绿色建筑落成于2008年,但加州科学院却已有160年历史,可谓集古老和现代于一身。     

四种鸭跖草科屋顶绿化植物对水分管控的响应

以牛轭草(Murdannia loriformis)、细竹篙草(M. simplex)、假紫万年青(Belosynapsis ciliata)及假紫万年青毛叶变种(B. ciliata var. vilosa)等4种植物为试材,探讨不同屋顶绿化植物在不同水分管理条件下的生长情况以及对干旱胁迫的响应。结果表明,4种植物在浇水周期较短(2 DIW和6 DIW,即每隔2 d和6 d浇一次水)的处理下,其地上部分和根系生物量积累较快,植株根系体量较大,侧根生长较多;而浇水周期较长(10 DIW和15 DIW)的处理减缓植株地上部分及根系生物量的积累;根系形态明显受到控制性浇水管理的影响。非充分浇水管理下(6 DIW和10 DIW)的植株在持续干旱胁迫下表现出较稳定的叶片相对含水量、根系活力和较好的抗旱性,而在频繁浇水管理(2 DIW)和浇水周期较长处理(15 DIW)后,4种植物在持续干旱胁迫下的生理响应都较为剧烈,表现出较差的抗旱能力。因此,在4种鸭跖草科植物建植期间可通过适度浇水(6～10 DIW),以维持植株较稳定的根系活力和较强的抗旱性。     

植物的根

大多数植物的根生长在土壤中,有的却不是这样.如吊兰的一些根生长在空气中;浮萍的根飘浮在水中;瓦松的根长在屋顶上;卷柏的根长在石缝中;檞寄生的根则是扎进树皮里. 1.根的功能根的主要功能是固定植物体,并从土壤中吸收水分、无机盐和一些CO_2以及少量的有机物.根除了吸收外还是个有机物的合成器官.有人用[~(15)N]进行示踪试验,证明根在30—40分钟内就能把吸收进来的含氮无机物转变(合成)为氨基酸或植物碱.玉米中有14种氨基酸可以在根部合成.烟草中的尼古丁、橡胶草中的橡胶等都是在根部合成的.     

佛甲草(Sedum lineare)在干旱条件下的气体交换

在干旱条件下,测定了广州市1、4、5和年期屋顶绿化植物佛甲草叶片的气体交换参数、相对含水量(RWC)和比叶重(LMA),探讨了佛甲草在屋顶绿化中的生理生态适应性.结果表明不同生长期佛甲草叶片的RWC和LMA相对较低,分别在81.79%～87.58%和0.059～0.072 kg·m^-2之间,RWC和LMA在不同生长期的差异不显著(P>0.05).不同生长期佛甲草的气体交换参数CO₂同化速率(A)、气孔导度(g_s)和蒸腾速率(E)均呈现相似的日变化格型,A、g_s和E的日均值差异不显著(P>0.05).A、g_s和E之间的日变化呈明显的正相关关系(P<0.01).根据植物的RWC和气体交换参数的特征,推断佛甲草属兼性CAM植物,不同生长期佛甲草的主要生理生态指标相似.     

屋顶柱式无土栽培法

在屋顶用标准和简易型立柱分别组建树林式光合生产单位,种植番茄、番薯等,营养液浇灌,结果都生长良好.此法栽培技术可供屋顶绿化时参考.     

Performance evaluation of native plants suited to extensive green roof conditions in a maritime climate

Assessing plant species performance on extensive green roofs can inform about and improve green roof functioning, aesthetics, longevity and the diversity of plant palettes available for the green roof industry. In this study, we evaluate survival, cover, roof cooling and stormwater retention properties of 15 plant species native to coastal regions of Atlantic Canada in extensive green roof monocultures. After a complete growing season (May-October 2009), all but one species had greater than 80% survival, and 10 species reached greater than 90% groundcover. Over the growing season, the top performing species reduced roof surface temperature by an average of 3.44 °C and increased solar reflectivity by 22.2% over the growing-medium only controls. Moreover, the best species retained 75.3% of experimentally added stormwater. Our results demonstrate that several species (mainly graminoids) performed better than creeping shrubs and forbs for most functions, although significant variation existed within life-form groups.     

Performance of dryland and wetland plant species on extensive green roofs

Background and Aims

Green roofs are constructed ecosystems where plants perform valuable services, ameliorating the urban environment through roof temperature reductions and stormwater interception. Plant species differ in functional characteristics that alter ecosystem properties. Plant performance research on extensive green roofs has so far indicated that species adapted to dry conditions perform optimally. However, in moist, humid climates, species typical of wetter soils might have advantages over dryland species. In this study, survival, growth and the performance of thermal and stormwater capture functions of three pairs of dryland and wetland plant species were quantified using an extensive modular green roof system.

Methods

Seedlings of all six species were germinated in a greenhouse and planted into green roof modules with 6 cm of growing medium. There were 34 treatments consisting of each species in monoculture and all combinations of wet- and dryland species in a randomized block design. Performance measures were survival, vegetation cover and roof surface temperature recorded for each module over two growing seasons, water loss (an estimate of evapotranspiration) in 2007, and albedo and water capture in 2008.

Key Results

Over two seasons, dryland plants performed better than wetland plants, and increasing the number of dryland species in mixtures tended to improve functioning, although there was no clear effect of species or habitat group diversity. All species had survival rates >75 % after the first winter; however, dryland species had much greater cover, an important indicator of green roof performance. Sibbaldiopsis tridentata was the top performing species in monoculture, and was included in the best treatments.

Conclusions

Although dryland species outperformed wetland species, planting extensive green roofs with both groups decreased performance only slightly, while increasing diversity and possibly habitat value. This study provides further evidence that plant composition and diversity can influence green roof functions.     

小良热带人工阔叶混交林中屋顶鼠施氏亚种的食性及其生态学意义

Rattus rattus slandeni的食性资料是在小良人工阔叶混交林中通过200个鼠箱观察残留食物的方法收集到的。屋顶鼠摄食植物39种,主要为果实、种子部分,并大量捕食金龟子、蝉和蝗虫等昆虫,偶尔捕食小脊椎动物。植物性和动物性两大类残食的总出现率相近,5-10月以动物性食物为主,11-4月以植物性食物为主。该鼠搬运和遗弃果实、种子的行为,有助于植物种类的传布,大量捕食害虫,有利于该系统的生态平衡,故对其益害问题应作客观评价。     

Sedum cools soil and can improve neighboring plant performance during water deficit on a green roof

Green roofs have the potential to function as islands of biodiversity within urban and suburban environments. However, plant diversity is constrained by the harsh environment of a green roof, especially summertime water deficit and heat stress. We hypothesized that Sedum species, which are highly tolerant of the roof-top environment, would reduce peak soil temperature and increase performance of neighboring plants during summer water deficit. To test these hypotheses, we grew focal plant species with and without Sedum on a green roof. We then monitored growth during wet periods and drought tolerance during dry periods. During a three-year experiment, S. album reduced maximum growth of neighbor plants, Agastache rupestris and Asclepias verticillata, during favorable growth conditions, but increased performance of neighbors during summer water deficit. In a second experiment, four species of Sedum were each found to decrease peak soil temperature by 5-7 °C. All species decreased total growth of neighboring Agastache ‘Black Adder’ during favorable growth conditions, but again increased performance during summer water deficit. These results suggest that the palette of green roof plants can be expanded by using Sedum species as nurse plants.     

Multifunctionality is affected by interactions between green roof plant species,substrate depth,and substrate type

Green roofs provide ecosystem services through evapotranspiration and nutrient cycling that depend, among others, on plant species, substrate type, and substrate depth. However, no study has assessed thoroughly how interactions between these factors alter ecosystem functions and multifunctionality of green roofs. We simulated some green roof conditions in a pot experiment. We planted 20 plant species from 10 genera and five families (Asteraceae, Caryophyllaceae, Crassulaceae, Fabaceae, and Poaceae) on two substrate types (natural vs. artificial) and two substrate depths (10 cm vs. 30 cm). As indicators of major ecosystem functions, we measured aboveground and belowground biomasses, foliar nitrogen and carbon content, foliar transpiration, substrate water retention, and dissolved organic carbon and nitrates in leachates. Interactions between substrate type and depth strongly affected ecosystem functions. Biomass production was increased in the artificial substrate and deeper substrates, as was water retention in most cases. In contrast, dissolved organic carbon leaching was higher in the artificial substrates. Except for the Fabaceae species, nitrate leaching was reduced in deep, natural soils. The highest transpiration rates were associated with natural soils. All functions were modulated by plant families or species. Plant effects differed according to the observed function and the type and depth of the substrate. Fabaceae species grown on natural soils had the most noticeable patterns, allowing high biomass production and high water retention but also high nitrate leaching from deep pots. No single combination of factors enhanced simultaneously all studied ecosystem functions, highlighting that soil–plant interactions induce trade‐offs between ecosystem functions. Substrate type and depth interactions are major drivers for green roof multifunctionality.     

The inorganic component of green roof substrates impacts the growth of Mediterranean plant species as well as the C and N sequestration potential

Extensive green roofs substrates should meet a list of physicochemical and biochemical requirements to be used as a basis for plant growth: high water holding capacity, good aeration, low bulk density, and proper drainage are some of them. In recent years, the impact of different organic matter doses and the substrate depth on the subsequent plant growth have been deeply studied. By contrast, there are not many publications about the effect of the inorganic component of these substrates on plant development and C and N sequestration potential by the green roof system, and even more under semi-arid Mediterranean conditions. Four substrates were made by mixing the same compost, at 10% by volume, with different inorganic materials: CsB (compost, silica sand, and crushed bricks; 1:1:8), CB (compost and crushed bricks; 1:9), CSB (compost, clay-loam soil, and crushed bricks; 1:1:8), and CsS (compost, silica sand, and clay-loam soil; 1:1:8). These were placed, a depth of 10 cm, on “cultivation tables” in an experimental farm located in the SE of Spain. Two native species were sown in each substrate: Lotus creticus and Asteriscus maritimus. Physicochemical, nutritional, and biochemical properties of the substrates as well as the plant development were evaluated during a 10-month experiment. The CsB and CSB mixtures had good physicochemical properties (high porosity and acceptable water holding capacity) although the levels of C, N, and humic substances were higher in the soil-containing substrates than in the CB and CsB mixtures. The hydrolytic enzyme activity was also promoted in these mixtures. The plant growth pattern showed differences regarding the inorganic composition of the substrate; L. creticus had superior development in the CsB substrate and A. maritimus was able to grow in all tested substrate mixtures, although its cover was low, being a more versatile candidate to establish a green roof cover. The greatest C and N sequestration potential was achieved by the CsS mixture, reaching 1.06 kg TC m⁻² of green roof substrate. Therefore, substrate composition impacts the growth of native plant species as well as the C and N sequestration by the green roof system.     

Fine‐scale substrate heterogeneity in green roof plant communities: The constraint of size

Heterogeneity–diversity relationship (HDR) is commonly shown to be positive in accordance with classic niche processes. However, recent soil‐based studies have often found neutral and even negative HDRs. Some of the suggested reasons for this discrepancy include the lack of resemblance between manipulated substrate and natural settings, the treated areas not being large enough to contain species' root span, and finally limited‐sized plots may not sustain focal species’ populations over time. Vegetated green roofs are a growing phenomenon in many cities that could be an ideal testing ground for this problem. Recent studies have focused on the ability of these roofs to sustain stable and diverse plant communities and substrate heterogeneity that would increase niches on the roof has been proposed as a method to attain this goal. We constructed an experimental design using green roof experimental modules (4 m²) where we manipulated mineral and organic substrate component heterogeneity in different subplots (0.25 m²) within the experimental module while maintaining the total sum of mineral and organic components. A local annual plant community was seeded in the modules and monitored over three growing seasons. We found that plant diversity and biomass were not affected by experimentally created substrate heterogeneity. In addition, we found that different treatments, as well as specific subplot substrates, had an effect on plant community assemblages during the first year but not during the second and third years. Substrate heterogeneity levels were mostly unchanged over time. The inability to retain plant community composition over the years despite the maintenance of substrate differences supports the hypothesis that maintenance of diversity is constrained at these spatial scales by unfavorable dispersal and increased stochastic events as opposed to predictions of classic niche processes.     

Dandelion diaspore dispersal: frictional anisotropy of cypselae of Taraxacum officinale enhances their interlocking with the soil

Plant and Soil - Green roofs are important novel urban ecosystems, but their shallow substrates can create plant water deficits in dry climates. Physiological approaches can improve green roof...     

High water users can be drought tolerant: using physiological traits for green roof plant selection

Background and aims

Green roofs are often installed to reduce urban stormwater runoff. To optimally achieve this, green roof plants need to use water when available, but reduce transpiration when limited to ensure survival. Succulent species commonly planted on green roofs do not achieve this. Water availability on green roofs is analogous to natural shallow-soil habitats including rock outcrops. We aimed to determine whether granite outcrop species could improve green roof performance by evaluating water use strategies under contrasting water availability.

Methods

Physiological and morphological responses of 12 granite outcrop species with different life-forms (monocots, herbs and shrubs) and a common green roof succulent were compared in well watered (WW) and water deficit (WD) treatments.

Key results

Granite outcrop species showed a variety of water-use strategies. Unlike the green roof succulent all of the granite outcrop species showed plasticity in water use. Monocot and herb species showed high water use under WW but also high water status under WD. This was achieved by large reductions in transpiration under WD. Maintenance of water status was also related to high root mass fraction.

Conclusions

By developing a conceptual model using physiological traits we were able to select species suitable for green roofs. The ideal species for green roofs were high water users which were also drought tolerant.