Sedum Spurium Research Articles

ANATOMICAL STRUCTURE OF THE LEAFS OF ORNAMENTAL STONECROPS OF THE GENERA SEDUM L. AND HYLOTELEPHIUM H. OHBA UNDER CONDITIONS OF DIFFERENT LIGHT LEVELS

The paper presents the results of determining the quantitative and qualitative characteristics of the anatomical structure of the leaf of the ornamental stonecrops of the genera Sedum L. and Hylotelephium H. Ohba during the seasonal development at different levels of illumination in the conditions of the Kryvyi Rih Botanical Garden of the NAS of Ukraine, which is located in the steppe zone of Ukraine (arid agroclimatic zone).The objects of the study were the plants Hylotelephium ewersii, Hylotelephium spectabile, Sedum album, Sedum reflexum and Sedum spurium. Research was carried out on sites with different levels of illumination: a well-lit place of growth (control site) - the level of illumination at lunchtime reached 39,000–56,500 lux in clear weather and 14,500–23,500 lux on an overcast day; shadow area - the light level at lunch time in clear weather reached 2,500-3,500 lux, and on an overcast day 1,200-2,000 lux. The research was conducted in three stages: the end of May, the end of July, and the end of September. We used 5 individuals of each species, which were grown in open ground (ordinary black soil) at a natural level of moisture supply. Anatomical studies were performed on live specimens using standard methods. The material for the studies was preparations of morphologically mature leaves taken from the middle tier of individuals. It was found that during the seasonal development of plants, changes occur in the anatomical structure of leaves. In plants of H. ewersii, H. spectabile, S. reflexum and S. spurium, leaf thickness was greater in conditions of sufficient light and there was a decrease in leaf blade thickness during seasonal development (from May to September), both in the sun and in the shade. Under conditions of shade at the end of the season, leaf thickness decreased most significantly in H. spectabile and S. spurium - almost twice. On the other hand, in S. spurium, under insufficient lighting, the thickness of the lower and upper epidermis increased more than twice, and in H. spectabile, the thickness of the cuticle increased in both variants of the experiment - in the sun by 2.1 times, in the shade by 1.4 times. In stonecrops with flat leaves, the diameter of the central conducting bundle during the season in sunny conditions was 26 % (S. spurium) – 52 % (H. spectabile) larger than in the shade. Only in S. album, from May to September, leaf thickness and the diameter of the central conductive bundle, in absolute terms, were larger in the shade than in the sun. The obtained results indicate high plasticity of the studied species and peculiarities of phenotypic changes in the anatomical structure of leaves. Key words: family Crassulaceae, leaf anatomy, light level, steppe zone, Krуvorіzhzhуа, seasonal development

A novel stomatal resistance equation for modeling heat and mass transfer of extensive vegetative roofs

The cooling potential of vegetated roofs depends on the stomatal resistance (rs), leaf area index, and other factors. Sailor (2008) and Tabares-Velasco and Srebric (2012) are among the most cited heat and mass transfer vegetative roof models. They include different equations to estimate rs, which show large differences, and significantly overestimate rs under certain conditions. Therefore, their models offer particular opportunities for improvement to reflect the actual vegetation cooling potential. This is necessary to predict the impact of vegetative roofs more accurately on the building energy performance and the urban heat island effect. The rs of both vegetative roof heat and mass transfer models have been developed based on studies with species that are not commonly planted on vegetative roofs. It was found that both models overestimate the rs under certain conditions that could turn into the underestimation of the transpiration rates and the cooling potential. Consequently, this paper aims to develop a novel equation for rs based on field measurements in a semiarid climate. The species tested were Glandularia berterii (C3), Selliera radicans (C3), Phyla reptans (C3), Aptenia cordifolia (CAM), Sedum palmeri (CAM), and Sedum spurium (CAM). A New Linear Model (NLM) was formulated to estimate rs. The regressors of NLM are minimum stomatal resistance (rs,min), incident solar radiation (Rsh), leaf area index (LAI), substrate volumetric water content (VWC), and vapor pressure difference (VPD). The results show that rs,min and Rsh reflect 64 % of rs; the species with higher cooling potential were Selliera radicans, Sedum palmeri, and Sedum spurium due to higher LAI and lower/moderate rs,min; and, the NLM showed a better agreement with the measured rs, correcting points where Sailor (2008) and Tabares-Velasco and Srebric (2012) equations significantly overestimated rs. Finally, it was demonstrated that the developed NLM better represents the stomatal behavior and distinguishes the responses between C3 and CAM species.

Influence of vegetation type and climatological conditions on evapotranspiration from extensive green roofs

Evapotranspiration (ET) is the key hydrologic process governing the capacity of a green roof to retain rainfall as it regenerates available water storage space in the green roof substrate (soil) between rainfall events. In this field study, the impact of climatological conditions, vegetation type, and substrate depth on ET rates were evaluated from experimental, modular extensive green roofs installed in three climate regions in Canada: Calgary AB (Prairies), London ON (Great Lakes/St. Lawrence), and Halifax NS (Atlantic/ Maritime). Daily ET rates and cumulative ET over two field seasons were quantified for two substrate depths (10 and 15 cm), substrate only treatments (no vegetation), and four vegetation treatments (monoculture treatments of Sedum spurium, Sporobolus heterolepis, and Aquilegia canadensis, and a mixed species treatment consisting of the three aforementioned species). 73 %, 67 % and 33 % of the cumulative rainfall was returned to the atmosphere via ET over the two field seasons in Calgary, London and Halifax, respectively. Importantly, ET rates were shown to be a strong function of substrate moisture content as well as atmospheric forcing with the relative importance of each varying between the different cities. ET rates were typically greater in the mixed species treatment in comparison to the three monoculture treatments (Sedum spurium, Sporobolus heterolepis, and Aquilegia canadensis) and for deeper substrate depths, although ET rate enhancement with substrate depth was comparatively small. This study provides valuable insights on the impact of climatological conditions and green roof design parameters (i.e., vegetation type and substrate depth) on ET rates.

Promising species of the genus Sedum (<i>Crassulaceae</i>) of the Orenburg branch of the Federal Horticulture Center for Breeding, Agrotechnology and Nursery

The article summarizes the results of observations of the promising samples of the genus Sedum of the genetic collection of ornamental crops of the Orenburg branch of the Federal Horticultural Center for Breeding, Agrotechnology and Nursery. Investigation of the features of the development phases and evaluation of the prospects of introduction of 7 species and 1 variety (Sedum selskianum Regel & Maack, Sedum dasyphyllum L., Sedum spurium cv. Rubi Glou, Sedum gybridum L., Sedum rupestre L., Sedum acre L., Sedum album L., Sedum ewersii Ledeb.) were held in 2019-2021. The phenological phases of the development of collection samples were studied, the prospects of introduction in the conditions of the steppe zone of the Southern Urals were evaluated. The studied groundcover perennials are assigned to the group of long-term vegetating plants. The beginning of the growing season of the studied samples was observed in the second decade of April, the sum of positive temperatures during the study period ranged from 158.7 to 207.4 ˚C; the temperature index above 5 ˚C over the years of research ranged from 50.6 to 81.9 C. The deployment of young leaves and the beginning of spring regrowth was noted after 7-12 days at the sum of active temperatures from 56.4 to 153.4 ˚C. The duration of the flowering period varies among the studied samples, the longest flowering is characteristic of S. selskianum, S. srurium cv., S. album. The onset of fruit maturity in various species is observed from the second decade of June to the second decade of July, in S. ewersii – in the second decade of September. Groundcover species of the genus Sedum in the conditions of the steppe zone of the Southern Urals are distinguished by a long (from 49 ± 4 days in S. acre to 64 ± 3 days in S. ewersii) period from the beginning of spring regrowth to the onset of flowering. The period from the onset of flowering to fruit ripening ranges from 29 ± 4 days for S. selskianum to 62 ± 3 days for S. album. According to the results of the study, 3 promising samples were identified for widespread use in landscaping.

Effects of biodiversity in green roofs and walls on the capture of fine particulate matter

Exposure to ambient PM2.5 poses serious threats to human health. In such cases, the presence of green roofs (GRs) and green walls (GWs) has several environmental benefits, including the capture of pollutants. Choosing appropriate designs of GWs and GRs to improve urban air quality is challenging because their performances depend on their constituent species and environmental characteristics of the particular locality. Capture of PM2.5 by different plant species of GRs and GWs has been measured only on monocultures. The impact of planting different species together (polycultures) on capturing PM2.5 remains unexplored. This paper aims to evaluate the impact of biodiverse GRs and GWs on PM2.5 capture. Seven species were analyzed as polycultures: Sedum album, Lampranthus spectabillis, Sedum spurium P, Lavandula angustifolia, Erigeron karvinskianus, Aptenia cordifolia, and Sedum palmeri. PM2.5 capture was measured by two methods: gravimetric determination and decay curve. Gravimetric results suggest that higher the biodiversity of plants in GRs and GWs, higher the PM2.5 capture, particularly for species with relatively low capture when used as monocultures. The ability to capture PM2.5 is dependent on the plant species, relative position of plants within the polyculture, and horizontal (GRs) or vertical (GWs) layout. Decay method results suggest that polycultures could be more effective in long-term reduction of high PM2.5 concentrations.

Vegetation recovery in open cast mines of Tver Region

In the study natural plant communities appearing at the first stages of vegetation recovery in open cuts are described. Sixty-three species of higher vascular plants were found, six of which are adventive (Bunias orientalis L., Cichorium intybus L., Cirsium arvense (L.) Scop., Melilotus albus Medik., Sedum spurium M.Bieb., Solidago canadensis L.). Species from the Asteraceae (15), Gramíneae (8), Fabáceae (7) families prevail. The predominant life form according to I. Serebryakov are long-rhizome. According to G. Zozulin’s classification, plants belonging to the meadow and birch formations are most common. The associations of Calamagrostis epigejos and Bromus inermis predominate. Cirsium arvense (L.) Scop., Heracleum sibiricum L., Campanula glomerata L. are single.

АНАЛІЗ ВЕГЕТАТИВНОГО РОЗВИТКУ ЖИВЦІВ РОСЛИН РОДУ SEDUM L. (CRASSULACEAE) ЗА УМОВ ОЗЕЛЕНЕННЯ ДАХІВ м. КИЄВА

The traits of vegetative parts (the length of the overground part of the cutting (shoot), the length of the underground part of the cutting (rhizome), the volume of the overground part of the cutting (shoot), the volume of the root system, the weight of the cutting (plant), and absolute cover area) for cuttings of five Sedum species (S. ewersii Ledeb., S. spathulifolium Hook. 'Cape Blanco', S. kamtschaticum Fisch. 'Variegatum', Sedum spurium M. Bieb., S. rupestre L.) were determined. The plants were cultivated for 86 days on a low roof (height = 6 m), in a soil mixture in 7-liter containers with a substrate height of 7 cm. The percentage of rooted cuttings reached 100% for S. ewersii, S. kamtschaticum 'Variegatum', S. spurium, S. rupestre and 66 % for S. spathulifolium 'Cape Blanco'. The highest ability to create absolute substrate cover was noted for species with creeping stems and flattened succulent leaves – S. kamtschaticum 'Variegatum' and S. spurium. This index was slightly lower for a species with vertical stems and stiff pointed, succulent leaves (S. rupestre), and plants with decumbent stems, that bear only the terminal rosettes of leaves (S. ewersii). The ability to substrate consolidation was not significantly different for S. ewersii, S. kamtschaticum 'Variegatum', S. spurium. Root development was lower for S. rupestre and very weak for S. spathulifolium 'Cape Blanco'. The results support planting S. ewersii, S. kamtschaticum 'Variegatum', S. rupestre, S. spurium with fresh harvested cuttings without previous rooting. Cuttings of S. spathulifolium 'Cape Blanco' increased their mass and projective cover slowly and required rooting before planting in a green roof

A comparison of the growth status, rainfall retention and purification effects of four green roof plant species

Vegetation is a key component of green roofs and one of the most important factors affecting the rainfall quantity and quality of green roofs. Four plant species (Sedum lineare Thunb., Sedum spurium ‘Coccineum’, Sedum aizoon L. and Sedum spectabile) and two planting methods (single-plant and mixed-plant) were tested on extensive green roofs (EGRs) in 2019. Plant growth status (plant height and vegetation coverage), rainfall volume control, nutrient concentration and load reduction were used to analyse the impact of the situation and the different plant growth conditions. The results showed that the growth status of Sedum lineare Thunb., Sedum aizoon L. and Sedum spectabile was great, and the vegetation coverage was more than 95% in summer. Each EGR with different sedum species had strong rainfall retention effects. The average retention rates of Sedum spectabile, Sedum lineare Thunb, mixed plants, Sedum aizoon L. and Sedum spurium ‘Coccineum’ were 90.98% and 91.38%, 88.51%, 83.42% and 84.17%, respectively. The average total nitrogen (TN) and nitrate nitrogen (NO3−-N) concentrations of Sedum lineare Thunb. were 13.77 mg/L and 7.64 mg/L, which were higher than those of other sedum species, and the average concentrations of ammonia nitrogen (NH4+-N) and total phosphorus (TP) of mixed plants were 4.01 mg/L and 0.48 mg/L, which were higher than those of single plants. Different plant species had different effects on nutrient loads. The EGRs of single plants and mixed plants indicated sinks of TN and NH4-N and sources of TP, but the performance of NO3−-N was inconsistent. Comprehensively, Sedum lineare Thunb., Sedum aizoon L. and Sedum spectabile were suitable for the green roofs. This study provides scientific support for the green roofs' application of actual projects and has a strong reference value for the development of green infrastructure.

Evaluation of the development of five Sedum species on extensive green roofs in a continental Mediterranean climate

Because of their easy implementation and low maintenance, extensive green roofs have become established during the last few decades as one of the best options for integrating vegetation on the built environment. The success of these systems involves having of a plant species palette well adapted to extreme conditions, especially in drought environments. Among the available ones, the Sedum genus has stood out due to its tolerance to climate extreme conditions and its use has been widespread throughout the world. In previous research, efforts have been mainly concentrated on selecting the most drought tolerant Sedum species, without considering other important parameters for the suitable provision of ecosystem services from the green roof, such as coverage capacity, shape and structure or growth strategy, among others. In this study, five species of Sedum (Sedum album, S. sediforme, S. sexangulare, Sedum spurium cf. öCoccineum’ (syn. Phedimus spurius cf. öCoccineum’) and Sedum spurium cf. öSummer Glory’ (syn. Phedimus spurius cf. öSummer Glory’) were tested in a dry continental Mediterranean climate with the aim of observing their patterns of growth and development. Results revealed that Sedum album, S. sediforme, S. sexangulare are recommended species for their use on extensive green roofs in this climate, whereas both varieties of S. spurium, particularly var. “Coccineum”, present some limitations for their use, basically due to their shape, plant structure, pigmentation and lack of adaptation to winter conditions. Shape Index could be an adequate tool for decision-making in the selection of plant species in the design of green roofs because it provides information not only about the shape and size but also related to the growth strategy of these plants.

The influence of plant type on green roof rainfall retention

Green roofs can mitigate the flood risk by reducing the volume of runoff through direct interception and subsequent evapotranspiration (ET), but the planting choices can influence the extent of this service. Glasshouse experiments were carried out in spring/summer using simulated rainfall to compare the rainfall retention capacity of three physiologically active broadleaf species (Heuchera micrantha, Salvia officinalis and Stachys byzantina), which have previously shown to provide improved rooftop cooling, to an industry standard green roof species, Sedum spurium. Furthermore, the impact of varying ambient temperature and humidity conditions on the ability of these species to restore the substrate retention capacity through ET was also tested in a series of controlled-environment experiments simulating a range of potential UK summertime scenarios. Canopies alone retained up to 17% (Sedum) of the total rainfall in this study, with Salvia and Stachys also retaining in excess of 10%, and can make a substantial contribution to rainfall retention on a green roof. Rainfall retention was also strongly correlated with total ET in the preceding 72 h (R2 = 0.94; P < 0.001). Species with high ET rates (Salvia and Stachys) were able to provide the greatest stormwater management service (up to 72% retention due to ET component). Furthermore, species ‘rankings’, in terms of ET and thus restoration of substrate retention capacity, were the same in all simulated potential UK summertime temperature and relative humidity scenarios, indicating that ‘superior’ species will be able to provide the greatest stormwater management provision in all climatic conditions.

Plant survival and growth on extensive green roofs: A distributed experiment in three climate regions

Green rooftops are installed in many climates worldwide to support urban ecosystem services. Across North America, green roofs often make use of the same limited set of plant species, but the effects of regional climates on the survival and growth of a core set of plant species has seldom been investigated. To identify the impact of climate on green roof plant performance, we installed an identical green roof system in three Canadian cities that experience different climate conditions: Calgary, Alberta; London, Ontario; and Halifax, Nova Scotia. The green roofs were monitored across three growing seasons for plant survival, plant height, and canopy density of three species grown in monoculture: Aquilegia canadensis, Sporobolus heterolepis, and Sedum spurium, and a mixture planting with all three species. Green roof vegetation canopy density, plant height and growth rates differed by city, plant species, substrate depth and planting type (monoculture or mixture treatment). Between sites, plant species exhibited different growth phenologies. Mixture treatments performed slightly better than monoculture plantings at each site in canopy density measures but were not significantly greater in plant height measures. The growth rate between years two and three was greatest for the mixture treatment, indicating greater potential for long term survival and performance of mixture plantings. The London, Ontario site, with a relatively moderate climate, supported the best green roof growth and performance compared to the cooler and drier Calgary and the rainier Halifax.

Evaluation of different establishment methods of sedum cuttings for summer vegetation of green roofs in Venetian Plain conditions

Sedum species are the most commonly used plants to vegetate green roofs because of their tolerance to extreme conditions. Despite the easier and faster establishment of sedums by plugs or mats, the direct spreading of cuttings is still an interesting cost-effective installation method, especially for large-scale roofs. To improve cutting establishment in the difficult conditions of the Venetian plain during summer, a three-way experimental design was set up on June 5, 2015. Rooted and un-rooted cuttings of five Sedum species (Sedum acre, S. album, S. reflexum, S. sexangulare and S. spurium) were compared with and without ground cover with non-woven fabric (fabric) in the first four weeks after cutting spreading (WAS). Cuttings survival and plant growth was evaluated over 20 weeks: 4 WAS (at fabric removal), after 12 and 20 WAS. Plant growth was measured by means of growth index, and shoot and root dry weights. After 4 WAS sedum cuttings were negatively affected by covering with fabric as only 68.5% of cuttings had survived compared to 98.5% of the uncovered control. Shoot and root dry weights were also negatively affected by fabric cover. At the end of the study both the fabric cover and Sedum species affected plant survival. Uncovered treatment exhibited better survival compared to the fabric cover (71.5 vs. 60.5%) while S. spurium and S. sexangulare had only 50% survival compared to the over 80% survival for S. acre. The sedum cuttings of the fabric cover treatment recovered over time, providing similar growth as the uncovered treatment at the end of the experiment. Sedum spurium had the highest growth index, shoot and root dry weights and S. album growth was also good. Pre-rooted cuttings did not affect survival but favored aerial growth of S. spurium and S. reflexum.

Design and Development of Low P-Emission Substrate for the Protection of Urban Water Bodies Collecting Green Roof Runoff

Urbanization leads to higher phosphorus (P) concentration in urban catchments. Among different stormwater retention measures, green roofs are the least efficient in phosphorus retention. Moreover, much research has shown that green roofs act as sources of phosphorus, and they can emit P in significant loads. In this study low P emission green roof substrate was developed based on the proposed step by step procedure for the selection of materials including laboratory tests, column experiments, and the monitoring of the open air green roof model. Developed substrate is the mixture of crushed red brick (35% of volume), crushed limestone (20% of volume), and sand (45% of volume), and is characterized by a bulk density of 1.52 g/cm3, water permeability of 9 mm/min, water capacity of 24.6% of volume, and granulometric composition that meets the Landscaping and Landscape Development Research Society (FLL) guidelines. Limestone was added to limit the potential P leaching from crushed red brick and vegetated mate consisted of Sedum album, Sedum acre, Sedum kamtschaticum, Sedum spurium, Sedum reflexum, Sedum sexangulare, Dianthus deltoides, Dianthus carthusianorum, and Thymus vulgaris. The open air model experiment was run for 319 days, from March 2015 to February 2016. The total water runoff from the green roof model amounted to 43.3% of runoff from the reference roof. The only one runoff event polluted with phosphorus was connected with the outflow of melted snow from an unfreezing green roof model.

Phytochemical Content, Antioxidant and Cytotoxic Activities of Sedum spurium

Sedum L. species are used for their hemostatic, antidiarrheal, antifungal, diuretic and wound healing properties, and there is growing interest in these species because of their usage in folk medicine. DPPH, SO, NO, and ABTS radical scavenging activities and protective effects against H(2)(02) induced cytotoxicity, as well as cytotoxic activities against the Hep-2 cell line of various extracts from Sedum spurium Bieb. were investigated. Besides, the total phenol, flavonoid, and flavonol contents of the extracts were determined to clarify their biological and phytochemical properties. Chromatographic studies on the most active extract led to the isolation of the major compound, identified as 2-methyl-erythritol by (1)H and (13)C NMR techniques. The EtOAc extract is found to be the most active extract in all tests. However, major compound of EtOAc extract did not possess tested activities. The EtOAC extract of S. spurium could be effective to improve antihemolytic defences of erythrocytes, and radical scavenging potential of the antioxidant mechanism. The extracts should be investigated in detail for their cytotoxic activities because of their possible pro-oxidant effects at high concentrations.

Unseen beauty of flowers – hidden signals or spectacular by-product?

The picture on the cover of this issue shows the ultraviolet-induced visible fluorescence of the Caucasian Stonecrop flower Phedimus spurius (sometimes referred to as Sedum spurium) collected in St...

Colonization of green roof plants by mycorrhizal and root endophytic fungi

Green roof plants must survive hot and dry conditions in low nutrient artificial growing media. Although soil microorganisms such as arbuscular mycorrhizal fungi (AMF) can ameliorate these constraints by increasing water and mineral uptake, virtually nothing is known about the microbes associated with the roots of green roof plants. We determined levels of AMF and dark septate endophyte (DSE) colonization of plants grown for four years on an experimental green roof in Halifax, Nova Scotia. Green roof plant species included the forb Solidago bicolor, the grasses Danthonia spicata and Poa compressa and the succulent Sedum acre. We also assessed root colonization of these same species, as well as three additional succulents (Sedum spurium, Rhodiola rosea and Hylotelephium telephium), collected from their natural habitats. We further assessed the inoculum potential of a commercial green roof substrate before and after the introduction of host plants. Levels of AMF colonization were similar within plant species, regardless of collecting location (roof or field). All plant species were colonized except for the succulent S. acre, which is commonly utilized as a green roof plant. The commercial growing medium contained extremely low levels of viable AMF propagules, but this increased significantly after planting with Solidago. Conversely, all species (from roof, field and bioassay) were well colonized by DSE, which appear to differ from the AMF with respect to their pattern of dispersal onto the green roof. Although the widespread use of non-mycorrhizal succulent species such as S. acre precludes the ecosystem services provided by the AMF symbiosis, the benefits of both succulent tissue and AMF could be obtained simultaneously with careful green roof plant selection.

Carbon dioxide sequestration model of a vertical greenery system

A dynamic model simulating carbon dioxide (CO2) sequestration by plants embedded in a vertical greenery system (VGS) was developed. The aim of the model was to demonstrate the advantages, in terms of CO2 sequestration, obtained by installation of large vegetated wall surfaces in urban areas. The ability of various plants, tested separately or in a mixed-species set, to accumulate carbon in different compartments and moments of their life (plants, compost, soil and microbial biomass in soil) was quantified. The model simulates a series of processes, from planting and growth of herbaceous plants in the VGS to the end of their lives, when compost is produced from green residues and is added to agricultural soil. The amount of CO2 removed from the atmosphere is the portion finally stocked in the soil in the form of microbial biomass.The plants considered are commonly used in VGS because they are perennial and suitable for hydroponic culture. Typical Mediterranean climate was assumed for the VGS model. The herbaceous species selected were the perennial grass Zoysia matrella, the succulent Sedum spurium, Mediterranean shrubs Salvia nemorosa and Rosmarinus officinalis and flowering ornamental plants Geranium sanguineum, Carex brunnea and Fatsia japonica.As estimated by the model, the mean yearly CO2 flow absorbed by plant biomass of these species (expressed in carbon dioxide equivalents, CO2eq) was 0.44–3.18kg CO2eqm−2 of vertical garden. Green residues from plant replacement and trimming/pruning were treated to produce compost and added to agricultural soil. We estimated that a 98m2 VGS can capture an average carbon dioxide flow of 13.41–97.03kg CO2eq per year. The model predicts increasing long-lasting carbon dioxide accumulation in the VGS over time, indicating a feasible solution for climate change mitigation in urban areas. The model can be adapted to different plant species and different geographical, climatic and biological conditions.

Evaluation of Plantable Containers for Groundcover Plant Production and Their Establishment in a Landscape

The demand for groundcover plants for landscape use is increasing. Plantable containers are becoming available in sizes appropriate for groundcover plants. Landscapers are seeking ways to decrease the time required to prepare and plant groundcover beds. Studies were conducted in 2011 and 2012 to evaluate plantable containers for a variety of groundcover plants. The study has shown that ‘Bronze Beauty’ ajuga (Ajuga reptans), ‘Herman’s Pride’ lamiastrum (Lamiastrum galeobdolon), ‘Beacon Silver’ lamium (Lamium maculatum), ‘Immergrunchen sedum (Sedum hybridum), ‘Red Carpet Stonecrop’ sedum (Sedum spurium), and ‘Vera Jameson’ sedum (Sedum telephium) were grown to a marketable size from 1.5-inch plugs in 8 weeks in Lexington, KY, when transplanted in May through August. ‘Big Blue’ liriope (Liriope muscari) from bare root bibs required 12 weeks. Plant growth in a 90-mm paper container and 80-mm bioplastic container was similar to that of plants grown in standard 3-inch rigid plastic containers and required 20% less time to transplant into the landscape and grew rapidly after transplanting in the field. Peat containers in this production system yielded smaller plants and slower ground coverage after transplanting in the field than plants grown in the other containers.

Changes of osmotic adjustment substances and activities of protective enzymes in Sedum spurium 'Coccineum' introduced to Xigaze, Tibet.

Sedum spurium ‘Coccineum' has carmine leaves and red flowers,which is an excellent urban greening plant with strong cold and drought tolerance.In order to expand its application range and enrich the greening materials for hostile habitats,S.spurium‘Coccineum'was introduced from Harbin to Xigaze,Tibet and grew well.The physiological adaptability of S.spurium ‘Coccineum'was studied in the present study.The results showed that with the extension of planting time,the content of malondialdehyde(MDA) in S.spurium ‘Coccineum'leaves gradually increased,the increment was not significant.Proline content first decreased and then increased.The activities of superoxide dismutase(SOD),peroxidase(POD) and catalase(CAT) all presented the tendency of "first increase then decrease".It was suggested that S.spurium could adjust its physiological metabolism through increasing the contents of osmotic adjustment substances and enhancing the activities of protective enzymes,hence,adapted the high radiation,drought conditions of Xigaze.

Optimal Growing Substrate pH for Five Sedum Species

To determine the optimal growing substrate pH values for Sedum plants, Sedum album, Sedum reflexum ‘Blue Spruce’, Sedum spurium ‘Dragon’s Blood’, Sedum hybridum ‘Immergrunchen’, and Sedum sexangulare were grown in containers using peatmoss and perlite-based substrates at five target pH levels (i.e., 4.5, 5.5, 6.5, 7.5, and 8.5). Optimal pH levels, calculated from dry weight regression models, were 6.32, 6.43, 5.71, 6.25, and 5.91 for S. album, S. reflexum, S. spurium, S. hybridum, and S. sexangulare, respectively, and 5.95 overall. Sedum spurium dry weight varied the most among pH treatments (i.e., 9.5 times greater at pH 6.3 vs. 8.3), whereas S. reflexum varied the least (i.e., 1.3 times greater at pH 6.3 vs. 4.4), indicating species-specific growth responses to growing substrate pH. These findings identified a narrow range of optimal growing substrate pH levels within a wider pH range tolerated by five Sedum spp. Therefore, by adjusting substrate pH to optimal levels, Sedum growth can be maximized.