Time-Dependent Changes in the Physico-Chemical Parameters and Growth Responses of Sedum acre (L.) to Waste-Based Growing Substrates in Simulation Extensive Green Roof Experiment

Over the last decade, an increase in the use of locally available, recycled, and waste materials as growing media components have occurred in various regions of the world in extensive green roof technology. For eco-concept reasons, such a strategy appears to be appropriate, but can be problematic due to difficulties in obtaining proper parameters of growing substrate. The growing media should be properly engineered in order to enable the proper functioning of green roofs and provide suitable environment for ideal root growth. The aim of the study was to assess the utility of locally occurring waste materials for growing media composition and estimate plant- and time-dependent changes in the physico-chemical parameters of waste-based substrates in a simulated extensive green roof system during a two-year Sedum acre L. cultivation. Five different substrate compositions were prepared using silica waste, crushed brick, Ca- and Zn-aggregates, melaphyre, tuff, sand, muck soil, urban compost, spent mushroom, and coconut fibres. Optimal water capacity, particle-size distribution, pH and salts concentration were found in all substrates. A higher concentration of macronutrients (N, P, K, Mg) and trace elements (B, Cu, Fe, Mn, Zn, Cd, Ni, Pb, and Cr) was found in waste-based substrates than in the commercial medium. In comparison to the parameters determined before establish the experiment, bulk density of tested growing media decreased, except for the substrates where the source of organic matter was the rapidly mineralising spent mushroom. The organic matter content in substrates after the two-year vegetation increased in relation to the ready-made substrate, with the exception of the composition with spent mushroom. After two years of the experiment, all available macronutrients and trace elements (with the exception of mineral N, K, SO4-S, and B) concentration were higher than in 2014, while pH, salt concentration was lower. In general, plants grown in waste substrates had lower dry matter content and higher biomass. A significantly higher biomass of S. acre L. was found in the first year of the experiment. In the second year of the research, the plants grown in the commercial medium, the substrate with silica waste, and the substrate with spent mushroom produced higher biomass than in the first year. No symptoms of abnormal growth were observed, despite the higher trace element concentrations in plants collected from waste-based substrate. Waste-based growing media can be considered as a valuable root environment for S. acre L. in an extensive green roof system.

Vegetation cover and plant diversity on cold climate green roofs

Both vegetation abundance and community composition play important roles in functions of green roofs (e.g. stormwater retention, habitat provision, aesthetic appearance). However, green roofs’ vegetation, and hence their functions, can change significantly over time. More understanding of these changes is required, particularly in cold climates. Therefore, this study investigated vascular plant covers and species compositions on 41 roof sections located in Sweden’s subarctic and continental climate zones. For the roof sections with a known originally intended vascular plant composition (n = 32), on average 24 ± 9% of the intended species were detected in surveys, and unintended species accounted for 69 ± 3% of the species found. However, most colonizing species formed sparse cover on the roofs. Thus, they may make less contributions to green roofs’ potential functionalities related to vegetation density (e.g. social perception, effectiveness in stormwater management and thermal performance) than the intended vegetation. The intended species dominated plant cover (93 ± 3%) and Sedum acre (58 ± 36% cover) was the most commonly detected species and as found in previous studies, substrate depth was positively related to both plant cover and species richness. Contrary to a hypothesis, the roofs’ vascular plant cover was not related to species richness but was significantly and negatively correlated with moss cover. The results highlight the importance of substrate depth for both plant abundance and species diversity and show that even in a cold climate, colonizing unintended species can strongly contribute to green roofs’ species richness.

Antioxidant potentials of the extracts from 14 selected medicinal plants

Most of the medicinal plants possess interesting antioxidant properties. The present study aimed to evaluate the antioxidant capacity of some medicinal plants from Turkey, such as Anthemis tinctoria L. (Compositae), Inula britannica L. (Compositae), Malabaila secacul Banks & Sol (Apiaceae), Zosima absinthifolia (Vent) Link (Apiaceae), Thymus sipyleus Boiss. (Lamiaceae), Phlomis armeniaca Willd. (Lamiaceae), Sideritis galatica Bornm. (Lamiaceae), Sedum acre L. (Crassulaceae), Potentilla erecta Uspenski ex Ledeb. (Rosaceae), Digitalis lamarckii Ivan (Scrophulariaceae), Glaucium grandiflorum Boiss. & Huet var. grandiflorum (Papaveraceae), Fumaria asepala Boiss. (Papaveraceae), Centranthus longiflorus Stev. (Valerianaceae), Allium rotundum L. (Amaryllidaceae). The ethyl acetate and methanol extracts of the 14 species were screened by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, superoxide anion (SO) radical scavenging, and lipid peroxidation (LPO) assays. The methanol and ethyl acetate extracts of Potentilla erecta have the highest DPPH scavenging activity (IC50=0.014 and 0.03 mg/mL, respectively). The maximum inhibition of LPO has been exhibited by ethyl acetate extract of Glaucium grandiflorum var. grandiflorum (IC50=0.34 mg/mL) followed by methanol extracts of T. sipyleus (IC50=0.38 mg/mL). The methanol extract of A. rotundum demonstrated the highest SO activity (IC50=0.11 mg/mL). In conclusion, these extracts have a high potential for antioxidant activity may be considered to use free radical-related diseases.

EFFECT OF SUBSTRATE DEPTH AND TYPE ON PLANT GROWTH FOR EXTENSIVE GREEN ROOFS IN A MEDITERRANEAN CLIMATE

Although numerous examples of green roofs can be found in Turkey, limited research has been conducted on plant material and substrate type in this climate. Both plants and substrate are very important components in green roof design, it is essential to determine the proper substrates and plants in green roof systems for domestic green roof design. Two types of growing substrates: a commercial substrate consisting of crushed brick and clay (45%), pumice (45%), and organic matter (10%), and a recycled substrate including 90% coarse pumice (10–20 mm) and municipal compost (10%), were tested in three depths of 4, 7 and 10 cm. Tested plant species included Achillea millefolium , Armeria maritima , Sedum acre and Sedum album . Overall, the commercial substrate performed better than the recycled pumice. In addition, deeper substrates promoted greater survival and growth for nearly all species tested. Either A. maritima or A. millefolium survived in the recycled pumice at any depth, whereas they did survive when grown in the commercial substrate in greater than 7 cm and 10 cm, respectively. They both likely would require supplemental irrigation to be acceptable for green roofs in Istanbul or locations with a similar climate. Both Sedum species survived in all substrate types and depths. Information gained can be utilized by green roof professionals in the Istanbul region and in other parts of the world with a similar climate.

Evaluating Native germplasm for extensive green roof systems for semiarid regions

Extensive green roofs (EGR) spaces constitute harsh and stressful growing environments, and consequently a limited range of plants species that can be routinely used there. The habitat template hypothesis suggests that EGR can be analogous as natural environments, what makes native plants as an alternative for these conditions. This paper aimed to assess the potential use of 15 native plants from Córdoba Province (Argentina) for green roofs, based on cover ability, survived rates and health status observations during a period of 414 days. Sedum acre L. was used as the control. Glandularia x hybrid, Phyla nodiflora (L.) Greene, Melica macra Nees, Eustachys retusa (Lag.) Kunth and Grindelia cabrerae Ariza kept up a 60% of coverage during all the period of study. The first two species had an outperformed green coverage (at 72th day; 95% and 98% respectively) in relation to the control species (Sedum acre; 87%). Eustachys retusa and Grindelia cabrerae grew progressively and kept their coverage constant proximally to 65%. Sedum acre, Grindelia cabrerae, Hysterionica jasionoides Willd, Melica macra, Phyla nodiflora, stood out in plant survival rates; but S. acre suffered changes in health status throughout the evaluation period, especially with low temperatures or at high humidity conditions. It is necessary to underline the reseeding potential of Eustachys retusa, a process that could guarantee perpetuation of the species on EGR.

Effect of Cold Storage on the Germination Success of Four Stonecrop Species

Green roof construction is constrained by cost of labor to install the plant material. Optimizing seed germination and establishment could significantly reduce installation costs but would require specific growing conditions that are difficult to provide during installation. Plants of the stonecrop (Sedum) genus are commonly used for the roof top because they will tolerate the high temperatures. This study compared the germination rates of four stonecrop species {goldmoss sedum (Sedum acre), ‘Oracle’ sedum (Sedum forsterianum), blue spruce sedum (Sedum reflexum), and amur sedum [Sedum selskianum (synonm Phedimus selskianum)]} at two temperatures, 70 and 90 °F, following storage of seed in dry, cool (40 °F) conditions of different durations (54, 98, 157, 197, 255, or 343 days). At 70 °F seed of goldmoss sedum, ‘Oracle’ sedum, and blue spruce sedum produced minimum germination rates of 60% at 21 days in seed stored for 54, 98, 157, 197, 255, or 343 days. Goldmoss sedum, ‘Oracle’ sedum, and blue spruce sedum showed reduced germination in 90 °F, probably due to temperature-induced dormancy. Amur sedum had germination of at least 83% at 21 days in both temperatures tested. As amur sedum germination rates appear to be unaffected in the temperatures tested, it could provide an excellent seed for use on green roofs where ideal temperatures are rarely available.

Evaluating a Natural Zeolite as an Amendment for Extensive Green Roof Substrate

This research examined soilless green roof substrate blends on an existing modular extensive green roof in Denver, Colorado, USA. Substrate blends evaluated include an extensive green roof substrate, Green Grid® and Green Grid® plus varying percentages of ZeoPro™ H-Plus. Plant taxa used included Sedum acre L., Sedum album L., Sedum spurium Marsch-Bieb. ‘Dragon's Blood’ and S. spurium ‘John Creech’. Substrate blends were evaluated based on plant taxa growth performance. Data collected included digital images to measure plant area covered using digital image analysis (DIA) and substrate volumetric moisture content (VMC). All data were analyzed over two growing seasons using the GLIMMIX procedure in SAS as multiple comparisons of substrate blends for each taxa, DIA data were analyzed from eight dates and VMC data were analysed from seven dates. The addition of zeolite (ZeoPro™) to the typical extensive green roof substrate improved establishment year plant cover for S. acre and S. album but hindered overwintering. Conversely, the two cultivars of S. spurium did not show a benefit of plant cover from the addition of ZeoPro™ in the first year but did the second year. As the percentage of ZeoPro™ in the substrate increased, VMC also increased.