Search Results (21)

Urban expansion has led to two significant environmental challenges: the reduction in green spaces and the rise in urban temperatures, decreasing city livability. Green roofs have emerged as a sustainable solution to mitigate these issues, offering ecological and economic benefits while improving building energy efficiency. Some species of the genus Sedum, particularly Sedum sediforme and Sedum album, are ideal for such green infrastructure due to their non-aggressive and superficial root system, high drought tolerance, low nutrient needs, pest and disease resistance, and metabolic adaptability during dry periods. This study aims to optimize the large-scale production of two native ecotypes of S. sediforme and S. album from the Valencian Community through an efficient propagation system that enables uniform plant production in limited space. For this purpose, we have developed micropropagation systems that allow a rapid multiplication of these two species. A direct morphogenesis system was established using axenic plant shoots, and a protocol for adventitious organogenesis from leaves was also developed. These methods significantly enhance propagation speed, spatial efficiency, and plant uniformity. Notably, the metabolic plasticity of S. sediforme and S. album reduces abiotic stress during acclimatization, promoting efficient ex vitro establishment and functional integration into extensive green roof ecosystems. Full article

Soil cadmium (Cd) pollution is a critical environmental issue that requires urgent remediation. Sedum alfredii Hance, known for its high biomass, strong stress tolerance, and suitability for harvesting, serves as an excellent hyperaccumulator. This study used field experiments to investigate the enhancement of Cd phytoremediation in soil using three activators: citric acid (CA), malic acid (MA), and polyaspartic acid (PASP). The results showed that the biomass of Sedum alfredii was increased by 8.95–28.37% by the addition of these activators, significantly boosting its Cd accumulation efficiency, with an average removal rate increase of 12%. Among all activators, CA exhibited the most substantial enhancement effect, with enrichment coefficients of 36.26% and 11.56% for the aboveground parts and roots of Sedum alfredii, respectively, and a 21.15% increase in the Cd removal rate. Although PASP had a less pronounced effect on biomass and Cd uptake, with decreases of 15.25% and 35.34% in the aboveground parts and roots, respectively, it significantly impacted soil Cd speciation and increased the activation rate by 20%. Full article

Crassulaceae plants are valued for their horticultural, ecological, and economic significance, but their genetic improvement is hindered by the absence of efficient and stable genetic transformation methods. Therefore, the development of a tailored genetic transformation method is crucial for enhancing the progress of the genetic improvement of Crassulaceae plants. The results indicate that, in the transformation experiments conducted on Kalanchoe tetraphylla, the K599 strain exhibited the highest transformation efficiency (76.67%), while C58C1 was least efficient (21.43%). An acetosyringone concentration of 100 μM was optimal for the hairy root transformation, and the immersion method yielded the highest efficiency. Additionally, the Silwet L-77 concentration significantly influenced the transformation efficiency, with 0.05% leading to a decrease. Upon four Crassulaceae species, notable differences were observed, with K. tetraphylla exhibiting the highest efficiency of 100%, and Sedum alfredii displaying the lowest efficiency of 5%. The RUBY reporter gene offers a more distinct advantage over GFP in observing the transformation effects. This study developed a simple, feasible, and cost-effective method for obtaining transgenic roots from leaves of Crassulaceae. The methodology provides technical support for the genetic improvement and gene function research of Crassulaceae plants. Full article

One of the most effective means of increasing urban green areas is the establishment of roof gardens. They have many positive properties and ecological functions, such as filling empty spaces with plants, protecting buildings, dust retention and air cleaning. In the case of extensive constructions, mostly Sedum species are used, planted as carpet-like “grass” sods or by installing modular units as plugs; however, with the use of other plant genera, the efficiency of ecological services could be increased by expanding the diversity. Festuca taxa have good drought resistance, and these plants tolerate temperature alterations well. Their application would increase the biodiversity, quality and decorative value of roof gardens. Experiments were carried out on nursery benches imitating a roof garden, with the use of modular elements intended for Sedum species, which facilitate the establishment of green roofs. In our trial, varieties of two European native species, Festuca glauca Vill. ‘Uchte’ and F. amethystina L. ‘Walberla’, were investigated. In order to find and determine the differences between the cultivars and the effects of the media (leaf mold and rhyolite tuff), we drew inferences after morphological (height, circumference, root weight, fresh and dry weight) and physiological tests (peroxidase and proline enzyme activity). We concluded that F. glauca ‘Uchte’ is recommended for roof garden conditions, planted in modular elements. Although the specimens were smaller in the medium containing fewer organic components than in the version with larger amounts, they were less exposed to the effects of drought stress. This can be a key factor for survival in extreme roof gardens or even urban conditions for all plants. Full article

The chemical composition of Sedum ewersii Ledeb., a plant indigenous to Kazakhstan and traditionally utilized in folk medicine, was comprehensively investigated, with a focus on its various plant parts. Fresh samples collected in May 2023 from the Almaty region underwent hydrodistillation to extract volatile components, followed by analysis using gas chromatography coupled with mass spectrometric detection, which identified a total of 71 compounds across different plant parts, including the root (underground part), root (aerial part), leaf, stem, and flowering aerial part. The predominant biologically active compound identified across all plant parts was Ethyl α-D-glucopyranoside. Monoterpenes, recognized as primary secondary metabolites, were notably abundant in each plant part, with varying compositions: the root (underground part) contained 28.58% aliphatic monoterpenes, 54.41% oxygenated monoterpenoids, 1.42% diterpenoids, and 15.59% other compounds; the root (aerial part) exhibited 1.34% aliphatic monoterpenes, 31.28% oxygenated monoterpenoids, 6.16% diterpenoids, and 61.22% other compounds; the stem and leaves showed 3.06% aliphatic monoterpenes, 21.49% oxygenated monoterpenoids, 17.99% diterpenoids, and 57.46% other compounds; and the flowering aerial part displayed 8.20% aliphatic monoterpenes, 53.18% oxygenated monoterpenoids, 23.75% diterpenoids, and 14.87% other compounds. Diterpenes, particularly Phytol, were prominently present in the leaf, stem, and flowering aerial parts. Additionally, a diverse array of organic acids, ketones, and phenolic compounds were identified across the plant parts, each potentially offering distinct pharmacological benefits. The presence of exclusive compounds in specific plant parts, such as Dihydroxyacetone in the root (aerial part), underscored the pharmacological diversity of S. ewersii. This study provides valuable insights into the chemical diversity and pharmacological potential of S. ewersii, suggesting promising applications in pharmaceutical and medicinal fields. Further research aimed at elucidating the individual and synergistic pharmacological effects of these compounds is crucial to fully harness the therapeutic benefits of this plant. Full article

Phytoextraction is a promising technology for remediating heavy metal-contaminated soil. Continuously screening potential plants is important for enhancing the efficiency of remediation. In this study, fourteen local native plant species and four cultivated plant species, along with their paired soils, were collected from around a copper smelter. The characteristics of soil pollution were evaluated using contaminant factors (CF) and a geoaccumulation index (Igeo). The phytoextraction potential of plants was investigated using the translocation factor (TF) and bioconcentration factor (BCF). The soils around the smelter were very acidic, with a mean pH of 5.01. The CF for copper and cadmium were 8.67–32.3 and 5.45–44.2, and the Igeo values for copper and cadmium were 2.43–4.43 and −0.12–2.29, respectively, indicating that the level of soil contamination was moderate to severe. The copper concentrations in the root (357 mg/kg), shoot (219 mg/kg), and leaf (269 mg/kg) of Elsholtzia splendens Nakai were higher than that in the other species. The cadmium in the shoot (32.2 mg/kg) and leaf (18.5 mg/kg) of Sedum plumbizincicola was the highest, and Phytolacca acinosa Roxb. had the highest cadmium level (20 mg/kg) in the root. Soil total and CaCl₂-extractable copper and cadmium were positively correlated with copper and cadmium in the plant roots, respectively. The results of TF and BCF for copper and cadmium suggested that the accumulation and translocation capacities for cadmium were higher than those of copper in the eighteen plant species. Although not all plants met the criteria of being hyperaccumulators, Sedum plumbizincicola, Mosla chinensis Maxim, and Elsholtzia splendens Nakai showed the most potential as candidates for the phytoextraction of copper and cadmium contaminated soils, as indicated by their TF and BCF values. Full article

The cadmium hyperaccumulator Sedum plumbizincicola has remarkable abilities for cadmium (Cd) transport, accumulation and detoxification, but the transcriptional regulation mechanisms responsible for its Cd hyperaccumulation remain unknown. To address this knowledge gap, we conducted a comparative transcriptome study between S. plumbizincicola and the non-hyperaccumulating ecotype (NHE) of Sedum alfredii with or without Cd treatment. Our results revealed many differentially expressed genes involved in heavy metal transport and detoxification that were abundantly expressed in S. plumbizincicola. Additionally, we identified a large number of differentially expressed transcription factor genes, highlighting the complexity of transcriptional regulatory networks. We further screened four transcription factor genes that were highly expressed in the roots of S. plumbizincicola as candidate genes for creating CRISPR/Cas9 knockout mutations. Among these, the SpARR11 and SpMYB84 mutant lines exhibited decreased Cd accumulation in their aboveground parts, suggesting that these two transcription factors may play a role in the regulation of the Cd hyperaccumulation in S. plumbizincicola. Although further research will be required to determine the precise targeted genes of these transcription factors, combined transcriptome analysis and CRISPR/Cas9 technology provides unprecedented opportunities for identifying transcription factors related to Cd hyperaccumulation and contributes to the understanding of the transcriptional regulation mechanism of hyperaccumulation in S. plumbizincicola. Full article

This research paper presents a case study analysis of the behavior of three Sedum varieties and their growth in three different types of substrates without additional watering or fertilizing. The study aims to identify a suitable substrate for propagation and to provide insight into the plant’s growth patterns. By analyzing the growth of the Sedum species and varieties—SS’PW’, SS’CB’, and SS’P’—without intervening in their growth process, we were able to identify factors that play a more crucial role in promoting root growth, plant growth, aesthetic value, and use. Over a 20-month period, various technical tools were employed to conduct observations and measurements for both plants and weather conditions. The type of substrate significantly affected plant growth, with the green roof substrate exhibiting the highest overall average monthly root growth rate (0.92 ± 0.05 d, 1.01 ± 0.05 b, 0.96 ± 0.05 c) while in the case of stem growth, among all three varieties, the best results were obtained in the commercial mix (0.87 ± 0.04 a, 0.40 ± 0.02 c, 0.35 ± 0.02 d). Based on the morphological analyses, all values were significantly lower than the control. Best results for leaf weight and surface area were noticed in the green roof substrate with an average growth of 46%, 53%, 55%, and for stem weight, length, and thickness in the commercial mix with 64%, 61%, and 55% compared to the control, respectively. Leaves had varying morphological characteristics, but the chromatic characteristics were preserved. The plants had an overall poor growth which may not be desirable in landscape designs. The findings of this study are applicable in the planning and execution of eco-friendly infrastructure initiatives, leading to the development of more robust and environmentally friendly urban settings. Full article

This study was conducted to identify soil cadmium (Cd) removal pathways and their contribution rates during phytoremediation by Pennisetum hybridum, as well as to comprehensively assess its phytoremediation potential. Multilayered soil column tests and farmland-simulating lysimeter tests were conducted to investigate the Cd phytoextraction and migration patterns in topsoil and subsoil simultaneously. The aboveground annual yield of P. hybridum grown in the lysimeter was 206 ton·ha⁻¹. The total amount of Cd extracted in P. hybridum shoots was 234 g·ha⁻¹, which was similar to that of other typical Cd-hyperaccumulating plants such as Sedum alfredii. After the test, the topsoil Cd removal rate was 21.50–35.81%, whereas the extraction efficiency in P. hybridum shoots was only 4.17–8.53%. These findings indicate that extraction by plant shoots is not the most important contributor to the decrease of Cd in the topsoil. The proportion of Cd retained by the root cell wall was approximately 50% of the total Cd in the root. Based on column test results, P. hybridum treatment led to a significant decrease in soil pH and considerably enhanced Cd migration to subsoil and groundwater. P. hybridum decreases Cd in the topsoil through multiple pathways and provides a relatively ideal material for phytoremediation of Cd-contaminated acid soils. Full article

The ascorbate (AsA)–glutathione (GSH) metabolism pathway is an important antioxidant system in cadmium (Cd) detoxification; the AsA–GSHpathway is generally regulated by a specific set of functional genes. However, transcription factors involved in AsA–GSH pathway have yet to be identified. Herein, we transformed a heat shock transcription factor SpHsfA4c from Sedum plumbizincicola into Populus. × canescens. Under 100 μM CdCl₂ stress for 30 d, the leaf chlorosis of wild-type poplars (WT) is more serious than that in transgenic poplars. The root biomass, shoot biomass and tolerance index (TIs) of transgenic poplars were higher than those in WT. In addition, transgenic poplars have higher Cd²⁺ uptake and Cd content. Compared with WT, the contents of hydrogen peroxide (H₂O₂) and superoxide anion (O₂^•−) in transgenic poplars were significantly reduced in leaves under Cd treatment. The expression levels of five enzymes (ascorbate peroxidase (APX), catalases (CAT), superoxide dismutase (SOD), peroxidase (POD) and glutathione S-transferase (GST)) were higher in transgenic poplars than those in WT. Transgenic poplars contained higher concentrations of intermediate metabolites, including GSH, AsA and phytochelatins (PCs), and a higher GSH/GSSG ratio in the AsA–GSH metabolism pathway. In Fourier transform infrared (FTIR) spectra, the characteristic peaks indicated that the contents of cysteine, GSH and AsA in transgenic poplars were exceeded compared to those in WT. These results suggested that SpHsfA4c can activate the AsA–GSH metabolism pathway to reduce Cd-associated oxidative stress. Therefore, overexpressing SpHsfA4c in P. × canescens can give rise to a superior Cd tolerance. Our results provide a theoretical significance for breeding potential new germplasm resources with high biomass and high Cd tolerance for remediation of soil heavy metal pollution. Full article

The occurrence of preferential flow in vegetated artificial substrates can weaken the stormwater management performance of green roofs. To explore preferential flow, various plant–substrate combinations that involved two Sedum species (Sedum sarmentosum and Sedum lineare) and two artificial substrates for three depths of 6, 10, and 14 cm were established. Artificial substrates without plants were either perlite-based (namely, PAS) or vermiculite-based (namely, VAS), and they were also set as controls. Thereafter, solute breakthrough experiments were conducted, followed by inverse and forward modeling in Hydrus-1D. Skewness coefficients of all solute breakthrough curves were non-zero, suggesting a prevalence of preferential flow. The Nash–Sutcliffe efficiency coefficients during calibration and validation were greater than 0.7. The obtained hydraulic parameters were different among various vegetated PAS and pure PAS without plants, but appeared the same for the VAS case. Rainfall intensity, plant species, and substrate depth, and the interaction of plant species and substrate depth all had significant effects on PAS preferential flow outflow and index (PFI). Substrate depth had a significant effect on VAS preferential flow and PFI. Since a 10 cm-PAS with S. lineare had the smallest PFI of 43.16% in simulation scenarios, its use may better control preferential flow in green roofs. Full article

Sedum alfredii Hance (S. alfredii) is a native hyperaccumulator plant species in China that has strong tolerance and accumulation ability for Zn and Cd. In addition, it is a good material for the phytoextraction of soil heavy metal pollutants. However, the specific effect of high Zn concentrations on the growth of S. alfredii and its metabolic mechanisms are not clear. Using an untargeted metabolomics method, we analysed the differential metabolites of the two ecotypes in S. alfredii roots under different Zn treatments. The results showed that high Zn levels significantly promoted plant growth in the hyperaccumulating ecotype (HE), while growth was inhibited in the non-hyperaccumulating ecotype (NHE). We detected 624 metabolites in the roots of S. alfredii. Under the high Zn treatment, lots of lipids and lipid-like molecules, such as glyceryl monooleate and 9,12,13-trihydroxyoctadecane-10-enoic acid, along with organic acids, such as lauramidopropylbetaine, L-malic acid, and their derivatives, decreased significantly in HE roots. Differential metabolites, such as some lipids and lipid-like molecules, were significantly upregulated in NHE roots. The above results indicate that the exogenous high Zn treatment induces the downregulation of HE differential metabolites in response to Zn, but significantly induces the upregulation of differential metabolites in NHE. Full article

Zinc (Zn)-regulated and iron (Fe)-regulated transporter-like proteins (ZIP) are key players involved in the accumulation of cadmium (Cd) and Zn in plants. Sedum plumbizincicola X.H. Guo et S.B. Zhou ex L.H. Wu (S. plumbizincicola) is a Crassulaceae Cd/Zn hyperaccumulator found in China, but the role of ZIPs in S. plumbizincicola remains largely unexplored. Here, we identified 12 members of ZIP family genes by transcriptome analysis in S. plumbizincicola and cloned the SpZIP2 gene with functional analysis. The expression of SpZIP2 in roots was higher than that in the shoots, and Cd stress significantly decreased its expression in the roots but increased its expression in leaves. Protein sequence characteristics and structural analysis showed that the content of alanine and leucine residues in the SpZIP2 sequence was higher than other residues, and several serine, threonine and tyrosine sites can be phosphorylated. Transmembrane domain analysis showed that SpZIP2 has the classic eight transmembrane regions. The evolutionary analysis found that SpZIP2 is closely related to OsZIP2, followed by AtZIP11, OsZIP1 and AtZIP2. Sequence alignment showed that most of the conserved sequences among these members were located in the transmembrane regions. A further metal sensitivity assay using yeast mutant Δyap1 showed that the expression of SpZIP2 increased the sensitivity of the transformants to Cd but failed to change the resistance to Zn. The subsequent ion content determination showed that the expression of SpZIP2 increased the accumulation of Cd in yeast. Subcellular localization showed that SpZIP2 was localized to membrane systems, including the plasma membrane and endoplasmic reticulum. The above results indicate that ZIP member SpZIP2 participates in the uptake and accumulation of Cd into cells and might contribute to Cd hyperaccumulation in S. plumbizincicola. Full article

Zn pollution is a potential toxicant for agriculture and the environment. Sedum alfredii is a Zn/Cd hyperaccumulator found in China and has been proven as a useful resource for the phytoremediation of Zn-contaminated sites. However, the molecular mechanism of Zn uptake in S. alfredii is limited. In this study, the function of SaPCR2 on Zn uptake in S. alfredii was identified by gene expression analysis, yeast function assays, Zn accumulation and root morphology analysis in transgenic lines to further elucidate the mechanisms of uptake and translocation of Zn in S. alfredii. The results showed that SaPCR2 was highly expressed in the root elongation zone of the hyperaccumulating ecotype (HE) S. alfredii, and high Zn exposure downregulated the expression of SaPCR2 in the HE S. alfredii root. The heterologous expression of SaPCR2 in yeast suggested that SaPCR2 was responsible for Zn influx. The overexpression of SaPCR2 in the non-hyperaccumulating ecotype (NHE) S. alfredii significantly increased the root uptake of Zn, but did not influence Mn, Cu or Fe. SR-μ-XRF technology showed that more Zn was distributed in the vascular buddle tissues, as well as in the cortex and epidermis in the transgenic lines. Root morphology was also altered after SaPCR2 overexpression, and a severe inhibition was observed. In the transgenic lines, the meristematic and elongation zones of the root were lower compared to the WT, and Zn accumulation in meristem cells was also reduced. These results indicate that SaPCR2 is responsible for Zn uptake, and mainly functions in the root elongation zone. This research on SaPCR2 could provide a theoretical basis for the use of genetic engineering technology in the modification of crops for their safe production and biological enhancement. Full article

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. Full article