Potentilla sericea stress-responsive spermine synthase PsSPMS enhances cadmium tolerance in Arabidopsis thaliana.

Potentilla sericea is resistant and tolerates rough management. It is an excellent garden groundcover for ecological restoration and soil consolidation for slope protection. Polyamines have functions such as promoting tissue growth and physiological resistance, while spermine synthase catalyzes the production of spermine. The PsSPMS gene from Potentilla sericea was cloned and transformed into Arabidopsis thaliana to study the response of transgenic Arabidopsis thaliana to cadmium stress. The results showed that the contents of spermidine, spermine as well as glutathione were higher in PsSPMS overexpressing Arabidopsis thaliana than the control, while the contents of putrescine were less than the control. Net photosynthetic rate, stomatal conductance, chlorophyll content, water use efficiency, electron transfer rate, PSII-related parameters, proline content, superoxide dismutase, and glutathione reductase activities were higher in PsSPMS overexpressing Arabidopsis thaliana than the control, while malondialdehyde, superoxide anion, and hydrogen peroxide contents were lower than the control. Correlation analysis showed significant differences between the indicators (P < 0.05 and P < 0.01). Expression of AtSPMS, AtSPD3, AtGSH2 and AtGR in transgenic Arabidopsis thaliana was higher than that of the control. Therefore, this study provides a genetic reference for the cultivation of cadmium-tolerant plants through genetic engineering and lays the foundation for further research on cadmium-tolerant Potentilla sericea.

Antiinflammatory effect of the ethanolic extract of Korean native herb Potentilla rugulosa Nakai in Bisphenol-a-stimulated A549 cells.

Potentilla rugulosa Nakai (P. rugulosa) is a perennial herb in the Rosaceae family and found in the Korean mountains. Previously, our findings demonstrated that P. rugulosa contains numerous polyphenols and flavonoids exhibiting important antioxidant and anti-obesity bioactivities. Bisphenol A (BPA) is a xenoestrogen that was shown to produce pulmonary inflammation in humans. However, the mechanisms underlying BPA-induced inflammation remain to be determined. The aim of this study was to examine whether ethanolic extract of P. rugulosa exerted an inhibitory effect on BPA-induced inflammation utilizing an adenocarcinoma human alveolar basal epithelial cell line A549. The P. rugulosa extract inhibited BPA-mediated cytotoxicity by reducing levels of reactive oxygen species (ROS). Further, P. rugulosa extract suppressed the upregulation of various pro-inflammatory mediators induced by activation of the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. In addition, inhibition of the NF-κB and MAPK signaling pathways by P. rugulosa extract was found to occur via decrease in the transcriptional activity of NF-κB. Further, blockade of phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and stress-activated protein kinase/Jun N-terminal kinase (SAPK/JNK) was noted. Thus, our findings suggest that the ethanolic extract of P. rugulosa may act as a natural anti-inflammatory therapeutic agent.

Potentilla anserina polysaccharide alleviates cadmium-induced oxidative stress and apoptosis of H9c2 cells by regulating the MG53-mediated RISK pathway.

Oxidative stress plays a crucial role in cadmium (Cd)-induced myocardial injury. Mitsugumin 53 (MG53) and its mediated reperfusion injury salvage kinase (RISK) pathway have been demonstrated to be closely related to myocardial oxidative damage. Potentilla anserina L. polysaccharide (PAP) is a polysaccharide with antioxidant capacity, which exerts protective effect on Cd-induced damage. However, it remains unknown whether PAP can prevent and treat Cd-induced cardiomyocyte damages. The present study was desgined to explore the effect of PAP on Cd-induced damage in H9c2 cells based on MG53 and the mediated RISK pathway. For in vitro evaluation, cell viability and apoptosis rate were analyzed by CCK-8 assay and flow cytometry, respectively. Furthermore, oxidative stress was assessed by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining and using superoxide dismutase (SOD), catalase (CAT), and glutathione/oxidized glutathione (GSH/GSSG) kits. The mitochondrial function was measured by JC-10 staining and ATP detection assay. Western blot was performed to detect the expression of proteins related to MG53, the RISK pathway, and apoptosis. The results indicated that Cd increased the levels of reactive oxygen species (ROS) in H9c2 cells. Cd decreased the activities of SOD and CAT and the ratio of GSH/GSSG, resulting in decreases in cell viability and increases in apoptosis. Interestingly, PAP reversed Cd-induced oxidative stress and cell apoptosis. Meanwhile, Cd reduced the expression of MG53 in H9c2 cells and inhibited the RISK pathway, which was mediated by decreasing the ratio of p-AktSer473/Akt, p-GSK3ßSer9/GSK3ß and p-ERK1/2/ERK1/2. In addition, Cd impaired mitochondrial function, which involved a reduction in ATP content and mitochondrial membrane potential (MMP), and an increase in the ratio of Bax/Bcl-2, cytoplasmic cytochrome c/mitochondrial cytochrome c, and Cleaved-Caspase 3/Pro-Caspase 3. Importantly, PAP alleviated Cd-induced MG53 reduction, activated the RISK pathway, and reduced mitochondrial damage. Interestingly, knockdown of MG53 or inhibition of the RISK pathway attenuated the protective effect of PAP in Cd-induced H9c2 cells. In sum, PAP reduces Cd-induced damage in H9c2 cells, which is mediated by increasing MG53 expression and activating the RISK pathway.

Phenols from Potentilla anserina L. Improve Insulin Sensitivity and Inhibit Differentiation in 3T3-L1 Adipocytes in Vitro.

Potentilla anserina L., a well-known perennial herb, is widely used in traditional Tibetan medicine and used as a delicious food in humans. The present investigation reports on the activity of P. anserina phenols (PAP) in regulating glycolipid metabolism in 3T3-L1 adipocytes. Insulin sensitivity tests showed that PAP improved insulin-stimulated glucose uptake by promoting the phosphorylation of serine/threonine kinase Akt. Moreover, an assay involving the differentiation of 3T3-L1 preadipocytes demonstrated that PAP also decreased the accumulation of lipid droplets by suppressing the expression of adipokines during the differentiation process. In addition, the underlying mechanism from the aspects of energy metabolism and oxidative stress is also discussed. The improvement in energy metabolism was supported by an increase in mitochondrial membrane potential (MMP) and intracellular ATP. Amelioration of oxidative stress was supported by decreased levels of intracellular reactive oxygen species (ROS). In summary, our findings suggest that PAP can ameliorate the disorder of glycolipid metabolism in insulin resistant 3T3-L1 adipocytes by improving energy metabolism and oxidative stress and might be an attractive candidate for the treatment of diabetes.

Potentilla fulgens upregulate GLUT4, AMPK, AKT and insulin in alloxan-induced diabetic mice: an in vivo and in silico study.

OBJECTIVE: This study was designed to investigate whether the glucose lowering effects of Potentilla fulgens acts by modulating GLUT4, AKT2 and AMPK expression in the skeletal muscle and liver tissues. METHODOLOGY: Alloxan-induced diabetic mice treated with Potentilla fulgens was assessed for their blood glucose and insulin level, mRNA and protein expression using distinguished methods. Additionally, GLUT4, AKT2 and AMPK were docked with catechin, epicatechin, kaempferol, metformin, quercetin and ursolic acid reportedly present in Potentilla fulgens. RESULTS: Potentilla fulgens ameliorates hyperglycaemia and insulin sensitivity via activation of AKT2 and AMPK, increases the expression of GLUT4, AKT2, AMPKα1 and AMPKα2 whose levels are reduced under diabetic condition. Molecular docking revealed interacting residues and their binding affinities (-4.56 to -8.95 Kcal/mol). CONCLUSIONS: These findings provide more clarity vis-avis the mechanism of action of the phytoceuticals present in Potentilla fulgens extract which function through their action on GLUT4, PKB and AMPK.

Potentilla anserina polysaccharide alleviates cadmium-induced oxidative stress and apoptosis of H9c2 cells by regulating the MG53-mediated RISK pathway / 中国天然药物

Oxidative stress plays a crucial role in cadmium (Cd)-induced myocardial injury. Mitsugumin 53 (MG53) and its mediated reperfusion injury salvage kinase (RISK) pathway have been demonstrated to be closely related to myocardial oxidative damage. Potentilla anserina L. polysaccharide (PAP) is a polysaccharide with antioxidant capacity, which exerts protective effect on Cd-induced damage. However, it remains unknown whether PAP can prevent and treat Cd-induced cardiomyocyte damages. The present study was desgined to explore the effect of PAP on Cd-induced damage in H9c2 cells based on MG53 and the mediated RISK pathway. For in vitro evaluation, cell viability and apoptosis rate were analyzed by CCK-8 assay and flow cytometry, respectively. Furthermore, oxidative stress was assessed by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining and using superoxide dismutase (SOD), catalase (CAT), and glutathione/oxidized glutathione (GSH/GSSG) kits. The mitochondrial function was measured by JC-10 staining and ATP detection assay. Western blot was performed to detect the expression of proteins related to MG53, the RISK pathway, and apoptosis. The results indicated that Cd increased the levels of reactive oxygen species (ROS) in H9c2 cells. Cd decreased the activities of SOD and CAT and the ratio of GSH/GSSG, resulting in decreases in cell viability and increases in apoptosis. Interestingly, PAP reversed Cd-induced oxidative stress and cell apoptosis. Meanwhile, Cd reduced the expression of MG53 in H9c2 cells and inhibited the RISK pathway, which was mediated by decreasing the ratio of p-AktSer473/Akt, p-GSK3βSer9/GSK3β and p-ERK1/2/ERK1/2. In addition, Cd impaired mitochondrial function, which involved a reduction in ATP content and mitochondrial membrane potential (MMP), and an increase in the ratio of Bax/Bcl-2, cytoplasmic cytochrome c/mitochondrial cytochrome c, and Cleaved-Caspase 3/Pro-Caspase 3. Importantly, PAP alleviated Cd-induced MG53 reduction, activated the RISK pathway, and reduced mitochondrial damage. Interestingly, knockdown of MG53 or inhibition of the RISK pathway attenuated the protective effect of PAP in Cd-induced H9c2 cells. In sum, PAP reduces Cd-induced damage in H9c2 cells, which is mediated by increasing MG53 expression and activating the RISK pathway.

[Potentilla anserina polysaccharide alleviates the damage of mouse glomerular mesangial cells induced by high glucose via promoting the expression of circ-AKT3].

Objective To explore the effect of Potentilla anserina polysaccharide on the injury of glomerular mesangial cells induced by high glucose and its possible mechanism. Methods High glucose was used to induce SV40 MES 13 mouse glomerular mesangial cells to establish a cell injury model, and 0.1, 0.3, 0.6 mg/mL Potentilla anserina polysaccharides were added to treat the cells. pcDNA and pcDNA-circ-AKT3 were respectively transfected into mesangial cells induced by high glucose. si-NC and si-circ-AKT3 were transfected into glomerular mesangial cells induced by high glucose and Potentilla anserina polysaccharide was added to the cells. The levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialedhyde (MDA) were tested according to the kit. The levels of IL-6, IL-18 and monocyte chemoattractant protein-1 (MCP-1) were detected by ELISA. Flow cytometry was used to detect the apoptosis rate. The real time quantitative PCR was used to detect the expression of circ-AKT3 mRNA. Results In glomerular mesangial cells induced by high glucose, the levels of SOD and GSH-Px were decreased, but the levels of MDA, IL-6, IL-18, and MCP-1 were increased, along with the increased rate of apoptosis, and decreased the expression level of circ-AKT3. After Potentilla anserina polysaccharide treatment of glomerular mesangial cells induced by high glucose, the levels of SOD and GSH-Px were increased whereas the levels of MDA, IL-6, IL-18, and MCP-1 were decreased, together with decreased apoptosis rate, and increased expression level of circ-AKT3. The difference was significant among different concentration groups. pcDNA-circ-AKT3 was transfected into glomerular mesangial cells induced by high glucose, followed by the increased levels of SOD and GSH-Px, with the decreased levels of MDA, IL-6, IL-18 and MCP-1. The apoptosis rate was also reported decreased. Interference of circ-AKT3 expression, on the other hand, can restore the protective effect of Potentilla anserina polysaccharide on high glucose induced glomerular mesangial cell injury. Conclusion Potentilla anserina polysaccharide can alleviate the damage of glomerular mesangial cells induced by high glucose by increasing the expression of circ-AKT3.

Potentilla anserine L. polysaccharide inhibits cadmium-induced neurotoxicity by attenuating autophagy.

Cadmium (Cd), a heavy metal with cytotoxicity, can activate autophagy. This study aimed to explore the effects and mechanisms of Potentilla anserine L. polysaccharide (PAP) on autophagy in N2a cells, primary neurons, and the brain of BALB/c mice exposed to Cd. The CCK-8 assay results showed that the cell viability decreased and the number of acidic vesicular organelles, autophagic vacuoles, lysosomes, and dysfunctional mitochondria increased in the cytoplasm of Cd-exposed N2a cells and primary neurons, as revealed by acridine orange staining, monodansylcadaverine staining, and transmission electron microscopy. PAP mitigated Cd-induced neuronal death and characteristic changes in autophagy. The expression of LC3 IILC3 II, Bcl-2, p62, Beclin-1, and PI3K class III was examined by Western blot analysis. Furthermore, the PI3K inhibitor (LY294002 or 3-MA) and/or PAP reversed the Cd-induced upregulated expression of LC3 II, Beclin-1, and PI3K class III, with a synergy between PI3K inhibitor and PAP against Cd-induced autophagy. The findings suggested that PAP partially prevented Cd-induced autophagic cell death in neurons by inhibiting the PI3K class III/Beclin-1 signaling pathway in vitro and in vivo.

Ectopic expression of SOD and APX genes in Arabidopsis alters metabolic pools and genes related to secondary cell wall cellulose biosynthesis and improve salt tolerance.

Hydrogen peroxide (H2O2) is known to accumulate in plants during abiotic stress conditions and also acts as a signalling molecule. In this study, Arabidopsis thaliana transgenics overexpressing cytosolic CuZn-superoxide dismutase (PaSOD) from poly-extremophile high-altitude Himalayan plant Potentilla atrosanguinea, cytosolic ascorbate peroxidase (RaAPX) from Rheum australe and dual transgenics overexpressing both the genes were developed and analyzed under salt stress. In comparison to wild-type (WT) or single transgenics, the performance of dual transgenics under salt stress was better with higher biomass accumulation and cellulose content. We identified genes involved in cell wall biosynthesis, including nine cellulose synthases (CesA), seven cellulose synthase-like proteins together with other wall-related genes. RNA-seq analysis and qPCR revealed differential regulation of genes (CesA 4, 7 and 8) and transcription factors (MYB46 and 83) involved in secondary cell wall cellulose biosynthesis, amongst which most of the cellulose biosynthesis gene showed upregulation in single (PaSOD line) and dual transgenics at 100 mM salt stress. A positive correlation between cellulose content and H2O2 accumulation was observed in these transgenic lines. Further, cellulose content was 1.6-2 folds significantly higher in PaSOD and dual transgenic lines, 1.4 fold higher in RaAPX lines as compared to WT plants under stress conditions. Additionally, transgenics overexpressing PaSOD and RaAPX also displayed higher amounts of phenolics as compared to WT. The novelty of present study is that H2O2 apart from its role in signalling, it also provides mechanical strength to plants and aid in plant biomass production during salt stress by transcriptional activation of cellulose biosynthesis pathway. This modulation of the cellulose biosynthetic machinery in plants has the potential to provide insight into plant growth, morphogenesis and to create plants with enhanced cellulose content for biofuel use.

Proteomic analysis of Potentilla fruticosa L. leaves by iTRAQ reveals responses to heat stress.

High temperature is an important environmental factor that affects plant growth and crop yield. Potentilla fruticosa L. has a developed root system and characteristics of resistance to several stresses (e.g., high temperature, cold, drought) that are shared by native shrubs in the north and west of China. To investigate thermotolerance mechanisms in P. fruticosa, 3-year-old plants were subjected to a high temperature of 42°C for 1, 2, and 3 days respectively before analysis. Then, we studied changes in cell ultrastructure using electron microscopy and investigated physiological changes in the leaves of P. fruticosa. Additionally, we used isobaric tags for relative and absolute quantification (iTRAQ) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to study proteomic changes in P. fruticosa leaves after 3 d of 42°C heat stress. we found that the cell membrane and structure of chloroplasts, especially the thylakoids in P. fruticosa leaves, was destroyed by a high temperature stress, which might affect the photosynthesis in this species. We identified 35 up-regulated and 23 down-regulated proteins after the heat treatment. Gene Ontology (GO) analysis indicated that these 58 differentially abundant proteins were involved mainly in protein synthesis, protein folding and degradation, abiotic stress defense, photosynthesis, RNA process, signal transduction, and other functions. The 58 proteins fell into different categories based on their subcellular localization mainly in the chloroplast envelope, cytoplasm, nucleus, cytosol, chloroplast, mitochondrion and cell membrane. Five proteins were selected for analysis at the mRNA level; this analysis showed that gene transcription levels were not completely consistent with protein abundance. These results provide valuable information for Potentilla thermotolerance breeding.

The accumulation of elements in plants growing spontaneously on small heaps left by the historical Zn-Pb ore mining.

The study evaluated the levels of nine metals, namely Ca, Cd, Fe, K, Mg, Mn, Pb, Tl, and Zn, in soils and tissues of ten plant species growing spontaneously on heaps left by historical mining for Zn-Pb ores. The concentrations of Cd, Pb, Tl, and Zn in heap soils were much higher than in control soils. Plants growing on heaps accumulated excessive amounts of these elements in tissues, on average 1.3-52 mg Cd kg(-1), 9.4-254 mg Pb kg(-1), 0.06-23 mg Tl kg(-1) and 134-1479 mg Zn kg(-1) in comparison to 0.5-1.1 mg Cd kg(-1), 2.1-11 mg Pb kg(-1), 0.02-0.06 mg Tl kg(-1), and 23-124 mg Zn kg(-1) in control plants. The highest concentrations of Cd, Pb, and Zn were found in the roots of Euphorbia cyparissias, Fragaria vesca, and Potentilla arenaria, and Tl in Plantago lanceolata. Many species growing on heaps were enriched in K and Mg, and depleted in Ca, Fe, and Mn. The concentrations of all elements in plant tissues were dependent on species, organ (root vs. shoot), and species-organ interactions. Average concentrations of Ca, K, and Mg were generally higher in shoots than in roots or similar in the two organs, whereas Cd, Fe, Pb, Tl, and Zn were accumulated predominantly in the roots. Our results imply that heaps left by historical mining for Zn-Pb ores may pose a potential threat to the environment and human health.

Bio-synthesis of silver nanoparticles using Potentilla fulgens Wall. ex Hook. and its therapeutic evaluation as anticancer and antimicrobial agent.

The present study aims to develop an easy and eco-friendly method for the synthesis of silver nanoparticles using extracts from the medicinal plant, Potentilla fulgens and evaluation of its anticancer and antimicrobial properties. The various parts of P. fulgens were screened and the root extract was found to have the highest potential for the synthesis of nanoparticles. The root extracts were able to quickly reduce Ag(+) to Ag(0) and stabilized the nanoparticles. The synthesis of nanoparticles was confirmed by UV-Visible spectrophotometry and further characterized using Zeta sizer, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM) and X-ray diffraction (XRD). Electron microscopic study showed that the size of the nanoparticle was in the range of 10 to 15 nm and spherical in shape. The studies of phytochemical analysis of nanoparticles indicated that the adsorbed components on the surface of nanoparticles were mainly flavonoid in nature. Furthermore, nanoparticles were evaluated as cytotoxic against various cancer cell lines and 0.2 to 12 µg/mL nanoparticles showed good toxicity. The IC50 value of nanoparticles was found to be 4.91 and 8.23 µg/mL against MCF-7 and U-87 cell lines, respectively. Additionally, the apoptotic effect of synthesized nanoparticles on normal and cancer cells was studied using trypan blue assay and flow-cytometric analysis. The results indicate the synthesized nanoparticle ability to kill cancer cells compared to normal cells. The nanoparticles also exhibited comparable antimicrobial activity against both Gram-positive and Gram-negative bacteria.

Physiological, biochemical and proteomics analysis reveals the adaptation strategies of the alpine plant Potentilla saundersiana at altitude gradient of the Northwestern Tibetan Plateau.

This study presents an analysis of leave and rood morphology, biochemical and proteomics approach as adaptation strategies of the alpine plant Potentilla saundersiana in an altitude gradient. Several plant physiological parameter, including root and leaf architecture, leaf photosynthesis capacity, specific leaf area (SLA) and leaf nitrogen concentration, histology and microscopy, anthocyanin and proline contents, antioxidant enzyme activity assay, in-gel enzyme activity staining, H2O2 and O2(-) content, immunoblotting, auxin and strigolactone content and proteomics analysis were evaluated at five different altitudes. P. saundersiana modulated the root architecture and leaf phenotype to enhance adaptation to alpine environmental stress through mechanisms that involved hormone synthesis and signal transduction, particularly the cross-talk between auxin and strigolactone. Furthermore, an increase of antioxidant proteins and primary metabolites as a response to the alpine environment in P. saundersiana was observed. Proteins associated with the epigenetic regulation of DNA stability and post-translational protein degradation was also involved in this process. Based on these findings, P. saundersiana uses multiple strategies to adapt to the high-altitude environment of the Alpine region. BIOLOGICAL SIGNIFICANCE: The alpine environment, which is characterized by sharp temperature shifts, high levels of ultraviolet radiation exposure, and low oxygen content, limits plant growth and distribution. Alpine plants have evolved strategies to survive the extremely harsh conditions prevailing at high altitudes; however, the underlying mechanisms remain poorly understood. The alpine plant Potentilla saundersiana is widespread in the Northwestern Tibetan Plateau. Here we adopted a comparative proteomics approach to investigate the mechanisms by which P. saundersiana withstands the alpine environment by examining plants located at five different altitudes. We detected and functionally characterized 118 proteins spots with variable abundance. Proteins involved in antioxidant activity, primary metabolites, epigenetic regulation, and protein post-translational modification play important roles in conferring tolerance to alpine environments. Furthermore, our results indicate that P. saundersiana modulates the root architecture and leaf phenotype to enhance adaptation to alpine environmental stress. These results provide novel insight into the multiple strategies underlying P. saundersiana adaptation to the high-altitude environment of the Northwestern Tibetan Plateau.

Effects of Potentilla fulgens as a Prophylactic Agent for Ischemia/Reperfusion Injury in the Rat Ovary.

OBJECTIVE: To investigate the effects of Potentilla fulgens as a prophylactic agent on ischemia/reperfusion (I/R) injury in the rat ovary. STUDY DESIGN: A total of 32 Wistar rats were divided into 4 equal groups: (I) sham, (II) ischemia, (III) ischemia + reperfusion, and (IV) IR + Potentilla fulgens. In groups I and II, ovary torsion was not performed and no drug was administered. In group III, 1 hour of ischemia and 2 hours of reperfusion were performed and no drug was given. Group IV received 400 mg/kg/day Potentilla fulgens intraperitoneally 5 days before I/R injury. RESULTS: The detorsion group showed preantral ovarian follicles and corpus luteum around the blood vessels and positive expression of vascular endothelial growth factor (VEGF). In the Potentilla fulgens group (IV) the stromal vascular endothelium with weak expression of VEGF was detected in small areas, and the ovarian follicles and the corpus luteum showed negative expression of VEGF. In the detorsion group the theca cells and apoptotic cells in preantral follicles showed positive expression of E-cadherin in the ovarian surface epithelium. Moreover, the E-cadherin expression was found to be positive in terms of follicular development, theca cells, granulosa cells, and corpus luteum. Potentilla fulgens, given after ischemic injury and apoptosis, was seen to decrease the effect of Bcl-2 expression. CONCLUSION: These results provide compelling evidence that the expression of E-cadherin in the ovary is an important component of ovarian function.

Whole-canopy carbon gain as a result of selection on individual performance of ten genotypes of a clonal plant.

Game theoretical models predict that plant competition for light leads to reduced productivity of vegetation stands through selection for traits that maximize carbon gains of individuals. Using empirical results from a 5-year competition experiment with 10 genotypes of the clonal plant Potentilla reptans, we tested this prediction by analyzing the effects of the existing leaf area values on the carbon gain of the different genotypes and the consequent whole canopy carbon gain. We focused on specific leaf area (SLA) due to its role in the trade-off between light capture area and photosynthetic capacity per unit area. By combining a canopy model based on measured leaf area and light profiles with a game theoretical approach, we analyzed how changes in the SLA affected genotypic and whole-stand carbon gain. This showed that all genotypes contributed to reduced stand productivity. The dominant genotype maximized its share of total carbon gain, resulting in lower than maximal absolute gain. Other genotypes did not maximize their share. Hypothetical mutants of the dominant genotype were not able to achieve a higher carbon gain. Conversely, in other genotypes, some mutations did result in increased carbon gain. Hence, genotypic differences in the ability to maximize performance may determine genotype frequency. It shows how genotypic selection may result in lower carbon gains of the whole vegetation, and of the individual genotypes it consists of, through similar mechanisms as those that lead to the tragedy of the commons.

Effects of increased nitrogen deposition and precipitation on seed and seedling production of Potentilla tanacetifolia in a temperate steppe ecosystem.

BACKGROUND: The responses of plant seeds and seedlings to changing atmospheric nitrogen (N) deposition and precipitation regimes determine plant population dynamics and community composition under global change. METHODOLOGY/PRINCIPAL FINDINGS: In a temperate steppe in northern China, seeds of P. tanacetifolia were collected from a field-based experiment with N addition and increased precipitation to measure changes in their traits (production, mass, germination). Seedlings germinated from those seeds were grown in a greenhouse to examine the effects of improved N and water availability in maternal and offspring environments on seedling growth. Maternal N-addition stimulated seed production, but it suppressed seed mass, germination rate and seedling biomass of P. tanacetifolia. Maternal N-addition also enhanced responses of seedlings to N and water addition in the offspring environment. Maternal increased-precipitation stimulated seed production, but it had no effect on seed mass and germination rate. Maternal increased-precipitation enhanced seedling growth when grown under similar conditions, whereas seedling responses to offspring N- and water-addition were suppressed by maternal increased-precipitation. Both offspring N-addition and increased-precipitation stimulated growth of seedlings germinated from seeds collected from the maternal control environment without either N or water addition. Our observations indicate that both maternal and offspring environments can influence seedling growth of P. tanacetifolia with consequent impacts on the future population dynamics of this species in the study area. CONCLUSION/SIGNIFICANCE: The findings highlight the importance of the maternal effects on seed and seedling production as well as responses of offspring to changing environmental drivers in mechanistic understanding and projecting of plant population dynamics under global change.

Do clonal plants show greater division of labour morphologically and physiologically at higher patch contrasts?

BACKGROUND: When growing in reciprocal patches in terms of availability of different resources, connected ramets of clonal plants will specialize to acquire and exchange locally abundant resources more efficiently. This has been termed division of labour. We asked whether division of labour can occur physiologically as well as morphologically and will increase with patch contrasts. METHODOLOGY/PRINCIPAL FINDINGS: We subjected connected and disconnected ramet pairs of Potentilla anserina to Control, Low, Medium and High patch contrast by manipulating light and nutrient levels for ramets in each pair. Little net benefit of inter-ramet connection in terms of biomass was detected. Shoot-root ratio did not differ significantly between paired ramets regardless of connection under Control, Low and Medium. Under High, however, disconnected shaded ramets with ample nutrients showed significantly larger shoot-root ratios (2.8∼6.5 fold) than fully-lit but nutrient-deficient ramets, and than their counterparts under any other treatment; conversely, fully-lit but nutrient-deficient ramets, when connected to shaded ramets with ample nutrients, had significantly larger shoot-root ratios (2.0∼4.9 fold) than the latter and than their counterparts under any other treatment. Only under High patch contrast, fully-lit ramets, if connected to shaded ones, had 8.9% higher chlorophyll content than the latter, and 22.4% higher chlorophyll content than their isolated counterparts; the similar pattern held for photosynthetic capacity under all heterogeneous treatments. CONCLUSIONS/SIGNIFICANCE: Division of labour in clonal plants can be realized by ramet specialization in morphology and in physiology. However, modest ramet specialization especially in morphology among patch contrasts may suggest that division of labour will occur when the connected ramets grow in reciprocal patches between which the contrast exceeds a threshold. Probably, this threshold patch contrast is the outcome of the clone-wide cost-benefit tradeoff and is significant for risk-avoidance, especially in the disturbance-prone environments.

Interaction of cadmium and zinc on accumulation and sub-cellular distribution in leaves of hyperaccumulator Potentilla griffithii.

Potentilla griffithii Hook is a newly found hyperaccumulator plant capable of high tolerance and accumulation of Zn and Cd. We investigated the interactive effects between Cd and Zn on accumulation and vacuolar sequestration in P. griffithii. Stimulatory effect of growth was noted at 0.2 mM Cd and 1.25 and 2.5 mM Zn tested. Accumulation of Zn and Cd in roots, petioles and leaves were increased significantly with addition of these metals individually. However, the Zn supplement decreased root Cd accumulation but increased the concentration of Cd in petioles and leaves. The results from sub-cellular distribution showed that up to 94% and 70% of the total Zn and Cd in the leaves were present in the protoplasts, and more than 90% Cd and Zn in the protoplasts were localized in the vacuoles. Nearly, 88% and 85% of total Cd and Zn were extracted in the cell sap of the leaves suggesting that most of the Cd and Zn in the leaves were available in soluble form. The present results indicate that Zn supplement significantly enhanced the petiole accumulation of Cd and further vacuolar sequestration plays an important role in tolerance, detoxification and hyperaccumulation of these metals in P. griffithii.

[Characteristics of 23 species of weed in northeast of China hyperaccumulating PAHs in contaminated soils].

Pot experiments were conducted to investigate the 23 species of weed accumulation characteristics of phenanthrene, as a representative of polycyclic aromatic hydrocarbons (PAHs), from soil in the northeast of China. The result indicated that among the 23 species, the bioconcentration factors of Taraxacum ohwianum K., Potentilla aiscolor B. and Chelidonium majus L. were all higher than 1, which were 1.01, 4.98, 38.24 respectively. The phenanthrene concentrations in roots were 2.83, 16.34 and 9.66 mg/kg which were lower than those in aboveground part with phenanthrene concentrations were 15.18, 74.70 and 573.62 mg/kg, respectively. The hyperaccumulators were indicated by strong conveyance of phenanthrene from root to aboveground part. The analysis of phenanthrene concentration in aboveground weed and aboveground plant biomass showed that the accumulation of phenanthrene in plant were not correlated with their biomass. It concluded that Taraxacum ohwianum K., Potentilla aiscolor B. and Chelidonium majus L. had hyperaccumulative characteristics of phenanthrene, and it is possible to screen out plants with high biomass and hyperaccumulation capability.

[The relationship between cytokines and the amount of nitrogen in the wintering organs of herbaceous plants].

The dynamics of cytokine content and the total protein and nonprotein forms of nitrogen in tissues of wintering organs of clary sage Salvia sclarea L. and cinquefoil Potentilla alba L. in abnormally cold (2005-2006 years) and abnormally warm (2006-2007 years) winters in Moscow have been studied. A direct correlation between the content of total cytokines and the total and protein nitrogen forms in tissues of wintering leaves and buds has been determined. A correlation link between the level of single cytokines and the protein nitrogen forms has been found.