Schoenoplectus Tabernaemontani Research Articles

Chromosome-Scale Genome Assembly for Soft-Stem Bulrush (Schoenoplectus tabernaemontani) Confirms a Clade-Specific Whole-Genome Duplication in Cyperaceae.

Schoenoplectus tabernaemontani (C. C. Gmelin) Palla is a typical macrophyte in diverse wetland ecosystems. This species holds great potential in decontamination applications and carbon sequestration. Previous studies have shown that this species may have experienced recent polyploidization. This would make S. tabernaemontani a unique model to study the processes and consequences of whole-genome duplications in the context of the well-documented holocentric chromosomes and dysploidy events in Cyperaceae. However, the inference was not completely solid because it lacked homology information that is essential to ascertain polyploidy. We present here the first chromosome-level genome assembly for S. tabernaemontani. By combining Oxford Nanopore Technologies (ONT) long reads and Illumina short reads, plus chromatin conformation via the Hi-C method, we assembled a genome spanning 507.96 Mb, with 99.43% of Hi-C data accurately mapped to the assembly. The assembly contig N50 value was 3.62 Mb. The overall BUSCO score was 94.40%. About 68.94% of the genome was comprised of repetitive elements. A total of 36,994 protein-coding genes were predicted and annotated. Long terminal repeat retrotransposons accounted for ∼26.99% of the genome, surpassing the content observed in most sequenced Cyperid genomes. Our well-supported haploid assembly comprised 21 pseudochromosomes, each harboring putative holocentric centromeres. Our findings corroborated a karyotype of 2n = 2X = 42. We also confirmed a recent whole-genome duplication occurring after the divergence between Schoenoplecteae and Bolboschoeneae. Our genome assembly expands the scope of sequenced genomes within the Cyperaceae family, encompassing the fifth genus. It also provides research resources on Cyperid evolution and wetland conservation.

Response of the functional traits of Schoenoplectus tabernaemontani to simulated warming in the Napahai wetland of northwestern Yunnan, China

The impact of climate warming on wetland ecosystems is a current focal point in ecological research. In this study, the Napahai wetland, a typical plateau wetland in northwest Yunnan Province, was selected as the study site to understand the growth and survival strategies of emergent plants in a plateau wetland under climate warming conditions. Open-top chambers (OTCs) were used to simulate warming in three treatments (i.e., control group, 2.0 ± 0.5°C, and 4.0 ± 0.5°C) in order to study the responses of the functional traits of the dominant emergent plant Schoenoplectus tabernaemontani to simulated warming. The results showed that simulated warming significantly reduced the photosynthetic carbon assimilation capacity and biomass accumulation of S. tabernaemontani, as well as its nitrogen content and vascular bundle density, while it significantly increased the vascular bundle size. The growing season accumulated temperature (AT) and the mean temperature of the hottest month (WT) were the main temperature factors influencing the functional traits of S. tabernaemontani. In summary, simulated warming significantly affected the functional traits of S. tabernaemontani, which demonstrated effective adaptation to warming conditions. As the temperature rises and the light and productivity decrease, S. tabernaemontani prioritizes the supply of limited resources to the underground part to ensure the biomass supply of the reproductive structure. This study provides a case for revealing the response patterns and ecological adaptation strategies of plateau wetland plants to climate warming.

Renoprotective effects of Schoenoplectus tabernaemontani rhizomes aqueous extracts against Adriamycin-induced nephropathy in rats

In recent years, chronic kidney disease (CKD) has emerged as an increasingly significant issue due to the growing prevalence and high treatment costs. While recorded the positive diuretic effect of Schoenoplectus tabernaemontani, there is a lack of reports on its efficacy in treating CKD. The pharmacological effects and mechanisms of Schoenoplectus tabernaemontani rhizomes aqueous extracts (STE) in CKD were investigated by inducing a rodent model of CKD via injection of Adriamycin (ADR; 7.5 mg/kg) into the tail vein of Wistar rats. In summary, our findings suggest that STE has a beneficial effect on anti-renal fibrosis and can reverse ADR-induced renal injury by suppressing oxidative stress and inflammation. Therefore, STE holds promising potential as a treatment option for CKD.

Plant trait-mediated drag forces on seedlings of four tidal marsh pioneer species

Salt marshes play an important role in coastal protection by reducing the impact of waves and shoreline erosion risks. While mature vegetation is responsible for the persistence and stability of marsh ecosystems, seedling survival of pioneer species is especially crucial for marsh propagation. Marsh seedlings, however, may be threatened by climate change induced increased coastal storm surge intensity and accompanying (extreme) wave conditions, imposing stronger drag forces on marsh seedlings. We test the hypothesis that drag forces experienced by seedlings increase with horizontal orbital velocity (Uw) in a species-specific manner, and that the drag forces experienced are individual-plant trait-mediated. To test our hypotheses, seedlings of four contrasting pioneer marsh species (Bolboschoenus maritimus, Schoenoplectus tabernaemontani, Spartina anglica, and Puccinellia maritima) were exposed to storm wave conditions in a flume, where Uw and experienced drag forces were measured. Linear mixed effect models demonstrated that seedling’s susceptibility to storm wave conditions is at least partly mediated by individual plant traits. Drag forces experienced by seedlings tended to increase with Uw, and with stem length and diameter. The interplay of both traits was complex, with increasing stem length being the most important trait accounting for increases in drag forces experienced at low to moderate Uw, while the stem diameter became more important with increasing Uw. Furthermore, experienced drag forces appeared to be affected by species-specific traits such as rigidity and leaf growth, being highest for Bolboschoenus maritimus and lowest for Puccinellia maritima. Our results provide important mechanistic insights into the drivers of tidal marsh seedling vulnerability to storm wave conditions due to experienced drag, both based on the traits of individual plants and species-specific ones. This type of knowledge is of key importance when modelling saltmarsh establishment and resilience under climate change.

Both species richness and growth forms affect nutrient removal in constructed wetlands: A mesocosm experiment

IntroductionPlant richness is thought to improve the function of constructed wetlands (CWs), but most CWs are planted with monocultures, with only a few employed polycultures, which have drawn contradictory conclusions. We suppose functional diversity is the key to better performance of plant communities and hypothesize that CWs planted with diverse growth forms are superior in plant growth and nutrient removal.MethodsIn this study, six emergent plant species categorized into slender type (Schoenoplectus tabernaemontani, Typha orientalis), fan type (Iris sibirica, Acorus calamus) and large type (Canna indica and Thalia dealbata) were planted in monocultures, combinations (two species of the same growth form) and mixed polycultures (six species of three growth forms). We then compared how plant growth and nutrient uptake differed among treatments.ResultsIt showed that the polyculture considerably increased the removal of total nitrogen (TN) and total phosphorus (TP), but the combination did not outperform monoculture. High consistency in the patterns between underground biomass and total biomass indicated that plant roots were essential for nutrient consumption. Compared with slender and fan plants, the large plants had a greater biomass increase in polycultures, which greatly accelerated the absorption and assimilation of TN and TP.ConclusionOur study indicated that plant community with various growth forms reduced the intensity of interspecific competition, increased the functional diversity, and greatly enhanced the ability of pollutant removal. Our results also provide some suggestions for plant selection and combination designs in CWs.

Effects of Hydrologic Pulsing and Vegetation on Invertebrate Communities in Wetlands

Constructed, mitigation wetlands in the midwestern United States are frequently dominated by a Typha spp. monoculture and their hydrologies are often determined by adjustable control structures. Wetlands provide habitat for multiple macroinvertebrate species, which in turn provide food for other organisms inhabiting the wetlands, such as waterfowl. This study examined the impacts of plant diversity and manipulated hydrology on macroinvertebrate communities. Forty 1-m2 wetland mesocosms were either planted with a monoculture of Typha spp. or with a more diverse plant community of Schoenoplectus tabernaemontani, Juncus effusus, and Sparganium eurycarpum. They were also assigned to one of four hydrologic regimes: steady state, pulsing, deep spring/shallow fall, and shallow spring/deep summer. After one year, macroinvertebrates were sampled in the mesocosms. Mesocosms with deep spring hydrologies were found to have greater taxon diversity than those with other hydrologies, but Chironomidae biomass was the lowest under the deep spring hydrology. Culicidae and Chironomidae were found in higher numbers in mixed vegetation than in Typha spp. Taxon richness and Chironomid biomass were significantly higher in mixed vegetation mesocosms than in Typha spp. monocultures. Results suggest vegetation diversity and hydrological regimes impact macroinvertebrate communities, with potential implications for constructed wetland design and management.

Responses of Four Peatland Emergent Macrophytes to Salinity and Short Salinity Pulses

Sea-level rise intensifies saltwater influx into coastal wetlands causing osmotic stress and probably changing vegetation composition. To determine especially the impact of salinity pulses that occur during flooding events, Typha latifolia, Carex acutiformis, Schoenoplectus tabernaemontani and Phragmites australis were exposed to different salinity regimes consisting of control (permanently freshwater and permanently brackish water) and alternating freshwater and brackish water with different exposure durations (2 days brackish – 2 days fresh; 4 days brackish – 4 days fresh; 2 days brackish – 4 days fresh). Plant height, leaf area, chlorophyll fluorescence, root:shoot ratio and photosynthetic pigments were measured. Salinity suppressed the growth of T. latifolia resulting in shorter height, smaller mean leaf area and higher root:shoot ratio. Carex acutiformis had smaller mean leaf area and higher root:shoot ratio. Photosynthetic pigment and chlorophyll fluorescence of both species were not affected. Shorter but frequent salinity pulses (alternate 2 days brackish – 2 days freshwater, and 2 days brackish – 4 days freshwater) decreased the leaf area of T. latifolia while C. acutiformis was not affected. Salinity and salinity pulses did not affect the height and root:shoot ratio of P. australis and S. tabernaemontani. Phragmites australis showed signs of successful acclimation through decreased chlorophyll a:carotenoid ratio and high fluorescence Δyield at low and high irradiance. Our results imply that with increasing seawater influx into coastal peatlands, T. latifolia and C. acutiformis may experience growth retardation or may even be replaced by S. tabernaemontani or P. australis since they are more resilient against salinity and frequent salinity pulses.

Using marsh organs to test seed recruitment in tidal freshwater marshes.

PremiseSeed recruitment niches along estuarine elevation gradients are seldom experimentally field‐tested under tidal regimes of the Pacific Northwest of North America. Addressing this knowledge gap is important to better understand estuary restoration and plant community response to sea level rise.MethodsGermination was tested in marsh organ mesocosms across an elevation gradient (0.5–1.7 m above mean sea level). Seeds were sown on sterile peat moss, and the tops of pipes were secured with horticultural “frost cloth” to ensure no experimental seeds were washed out and no new seeds were introduced. The trials tested artificial and overwinter chilling regimes, as well as the presence and/or absence of a near‐neighbor transplant.Results Carex lyngbyei had significant elevation‐driven germination after overwinter and artificial chilling. Schoenoplectus tabernaemontani had near‐significant germination across elevation after overwinter chilling, and germination in the absence of competition was significantly greater than with a near‐neighbor transplant.Discussion Carex lyngbyei had the highest germination rate at higher elevations, which suggests restricted seed recruitment potential and required clonal expansion to extend into lower marsh elevations. Identifying species‐specific recruitment niches provides insight for restoration opportunities or invasive species monitoring, as well as for estuary migration under sea level rise.

Responses of leaf hydraulic traits of Schoenoplectus tabernaemontani to increasing temperature and CO2 concentrations

BackgroundAgainst the background of a changing climate, the responses of functional traits of plateau wetland plants to increasing temperatures and CO2 concentrations need to be understood. Hydraulic traits are the key for plants to maintain their ecological functions and affect their growth and survival. However, few studies have comprehensively considered the response strategies of wetland plants' hydraulic traits to environmental changes in the context of water and matter transport, loss, and retention. According to the latest IPCC prediction results, we performed experiments under increased temperature (2 °C) and CO2 levels (850 μmol/mol) in an artificial Sealed-top Chamber (STC) to investigate the responses of the hydraulic characteristics of Schoenoplectus tabernaemontani, the dominant species in plateau wetlands in China.ResultsCompared with the CK group, net photosynthetic rate, transpiration rate, stomatal length, cuticle thickness, vascular bundle length, vascular bundle width, and vascular bundle area of S. tabernaemontani in the ET group were significantly reduced, whereas stomatal density and vein density increased significantly. Compared with the CK group, the hydraulic traits of S. tabernaemontani in the EC group were reduced considerably in stomatal length and cuticle thickness but increased dramatically in stomatal density, and there were no significant differences between other parameter values and the control group. Net photosynthetic rate was significantly positively correlated with stomatal length, cuticle thickness, and vascular bundle length, and stomatal conductance was significantly positively correlated with cuticle thickness. The transpiration rate was significantly positively correlated with cuticle thickness, epidermal cell area, vascular bundle length, vascular bundle width, and vascular bundle area. Regarding the hydraulic traits, there was a significant negative correlation between stomatal density and stomatal length, or cuticle thickness, and a significant positive correlation between the latter two. The epidermal cell area was significantly positively correlated with epidermal thickness, vascular bundle length, vascular bundle width, and vascular bundle area.ConclusionsIncreased temperature and CO2 levels are not conducive to the photosynthetic activity of S. tabernaemontani. Photosynthetic rate, stomatal density and size, vein density, epidermal structure size, and vascular bundle size play an essential role in the adaptation of this species to changes in temperature and CO2 concentration. In the process of adaptation, hydraulic traits are not isolated from each other, and there is a functional association among traits. This study provide a scientific basis for the management and protection of plateau wetlands.

Traits of tidal marsh plants determine survival and growth response to hydrodynamic forcing: implications for nature-based shoreline protection

Tidal marshes are increasingly valued for their nature-based shoreline protection function, as they reduce waves, currents and erosion. The effectiveness of this function depends on the ability of tidal marsh plants to grow and survive under pressure from waves and currents. However, how this varies with species-dependent plant traits is poorly understood. We performed a field transplantation experiment to quantify species-specific growth responses to different levels of hydrodynamic exposure and tidal inundation for 3 NW European marsh species: Schoenoplectus tabernaemontani, Bolboschoenus maritimus and Phragmites australis. In this order, these species showed increasing shoot stiffness, length and biomass, which are traits that increase hydrodynamic drag forces experienced by plants. Increased exposure to tidal inundation and hydrodynamics reduced the growth of all 3 species, but species with lower biomass and shorter, thinner and more flexible shoots could better cope with higher hydrodynamic exposure and tidal inundation. Furthermore, transplants of S. tabernaemontani (i.e. the species with the lowest shoot stiffness, length and biomass that survived under all tested conditions) developed smaller, thinner and more flexible shoots in response to higher hydrodynamic exposure and inundation. Hence our study indicates that similar inter- and intra-specific plant traits drive plant growth in response to hydrodynamics and inundation. This suggests that the spatial distribution of species typically observed in tidal marshes results not only from species-specific tolerance to tidal inundation gradients but also from hydrodynamic gradients. Allowing enough space for development of species zonation may be important to increase the efficiency of nature-based shoreline protection by tidal marshes.

Salinity exerted little effect on decomposition of emergent macrophytes in coastal peatlands

Climate-warming-driven sea level rise may change the vegetation composition of coastal wetlands, influencing ecosystem functions including photosynthetic activity, biomass production, litter decomposability and nutrient cycling. Litter decomposition rates of the most dominant macrophytes, Phragmites australis, Carex sp. and Schoenoplectus tabernaemontani, in two nearby freshwater and oligohaline peatlands were compared to determine the impact of salinity on litter decomposition. Electrical conductivity difference of 1.2–8.0 mS cm-1 (mean difference = 4.8 mS cm-1) between freshwater and oligohaline peatlands did not significantly affect the decomposition of macrophyte litter. Between species, S. tabernaemontani lost a significantly higher mass (29%) in the first month of decomposition compared to P. australis and Carex sp. Overall, litter decay rates for S. tabernaemontani was k = 0.0064–0.0078 d-1 while P. australis and Carex sp. both had k = 0.0017–0.0028 d-1. After one year, S. tabernaemontani litter was totally decomposed while the other species had 40–60% mass remaining relative to their initial dry mass confirming that P. australis and Carex sp. contribute to peat formation while S. tabernaemontani does not. Apparent differences in decomposition kinetics between S. tabernaemontani and the other species tested indicated that litter quality, especially C:P, C:N, N:P and C:Ca, is of great importance for both microbial colonization (initial phase) as well as for sustaining decomposition after colonization. This study shows that litter quality controls litter decomposition more than narrow salinity ranges. Hence, we suggest that sea level rise, combined with increased precipitation, may not have significant impact on the decomposition of these macrophytes in the future. However, sea level rise may lead to changes in vegetation composition replacing the peat-forming species by S. tabernaemontani which favors relatively deep, oligohaline wetlands. This would eventually affect carbon sequestration rates.

Survival of the thickest? Impacts of extreme wave‐forcing on marsh seedlings are mediated by species morphology

AbstractAlthough tidal marshes are known for their coastal defense function during storm surges, the impact of extreme wave forcing on tidal marsh development is poorly understood. Seedling survival in the first season after germination, which may involve exposure to extreme wave events, is crucial for the natural establishment and human restoration of marshes. We hypothesize that species‐specific plant traits plays a significant role in seedlings survival and response to wave induced stress, i.e., through stem bending and uprooting. To test this hypothesis, seedlings of pioneer species (Bolboschoenus maritimus, Schoenoplectus tabernaemontani, Spartina anglica, and Puccinellia maritima) with contrasting biophysical traits were placed in the Large Wave Flume in Hannover (Germany) and exposed to storm wave conditions. Seedlings of P. maritima and S. anglica experienced a lower loss rate and bending angle after wave exposure compared to S. tabernaemontani and especially B. maritimus. The higher loss rates of B. maritimus and S. tabernaemontani result from deeper scouring around the stem base. Scouring depth was larger around stems of greater diameter and higher resistance to bending. Here, B. maritimus and S. tabernaemontani have both thicker and stiffer stems than S. anglica and P. maritima. Our results show that especially seedlings with thicker stems suffer from erosion and scouring, and have the highest risk of being lost during extreme wave events. This implies that for successful seedling establishment and eventually the establishment of a mature tidal marsh vegetation, the species composition and their capacity to cope with storm wave disturbances is crucial.

Effects of a spatially heterogeneous nutrient distribution on the growth of clonal wetland plants

BackgroundClonal plants are important in maintaining wetland ecosystems. The main growth types of clonal plants are the guerrilla and phalanx types. However, little is known about the effects of these different clonal growth types on plant plasticity in response to heterogeneous resource distribution. We compared the growth performance of clonal wetland plants exhibiting the two growth forms (guerrilla growth form: Scirpus yagara, Typha orientalis, Phragmites australis and Sparganium stoloniferum; phalanx growth form: Acorus calamus, Schoenoplectus tabernaemontani and Butomus umbellatus) grown in soil substrates that were either homogeneous or heterogeneous but had the same total amount of nutrients.ResultsWe found that the morphological traits (plant height, ramet number, spacer diameter and length) and biomass accumulation of the guerrilla clonal plants (T. orientalis) were significantly enhanced by heterogeneity, but those of the phalanx clonal plants (A. calamus, S. tabernaemontani and B. umbellatus) were not. The results showed that the benefits of environmental heterogeneity to clonal plants may be correlated with the type of clonal structure.ConclusionsGuerrilla clonal plants, which have a dispersed, flexible linear structure, are better suited to habitats with heterogeneous resources. Phalanx clonal plants, which form compact structures, are better suited to habitats with homogeneous resources. Thus, wetland clonal species with the guerrilla clonal structure benefit more from soil nutrient heterogeneity.

Plant litter decomposition in wetlands is closely associated with phyllospheric fungi as revealed by microbial community dynamics and co-occurrence network

Phyllospheric microbes play a crucial role in the biological decomposition of plant litter in wetland ecosystems. Previous studies have mainly focused on single stages of decomposition process, and to date there have been no reports on dynamic changes in the composition of phyllospheric microbes during the multiple stages of decomposition from living plant to death. Here we investigated fungal and bacterial community succession in the leaf litter of Schoenoplectus tabernaemontani, a wetland plant species using sequencing of the both fungal ITS and bacterial 16S genes. Our results revealed that, over the whole period of decomposition, the fungal communities underwent more distinct succession than did the bacterial communities. Proteobacteria dominated throughout the entire period, while, across different decomposition stages, the Ascomycete fungi were gradually replaced by the Ciliophora and Rozellomycota as the dominant fungi. Network analysis revealed higher degrees of species segregation and shorter average path lengths between species of fungi compared with species of bacteria. This suggests that fungal communities may harbor more niches and functional diversity and are potentially more susceptible to external interference than are bacterial communities. During decomposition, the contents of leaf cellulose, hemicellulose and lignin in the litter were significantly (p < 0.01) correlated with the fungal communities, and abiotic factors accounted for 89.8% of the total variation in the fungal communities. In contract, abiotic factors only explained 6.10% of the total variation in bacterial communities, suggesting external environments as drivers of fungal community succession. Overall, we provide evidence that the complex litter decay in wetlands is the result of a dynamic cross-kingdom succession, and this process is accompanied by distinct phyllospheric fungal community dynamics.

Influence of hydrologic conditions on nutrient retention, and soil and plant development in a former central Ohio swamp: A wetlaculture mesocosm experiment

Agricultural runoff is a major contributor of nutrients to downstream freshwater and marine waters that, in turn, cause harmful algal blooms. “Wetlaculture,” a new landscape management approach defined as “integrating wetland nutrient removal with recycling of these nutrients to agriculture,” has the dual goals of reducing the need for fertilizer in agriculture while mitigating fluxes of nutrients to downstream aquatic ecosystems with created or restored wetlands. A mesocosm compound consisted of twenty-eight 380 L, 1-m2 tubs filled with local hydric soil was initiated in mid-2016 near a highly eutrophic Buckeye Lake in central Ohio, USA, to investigate the wetlaculture approach in an experimental fashion. In October 2016, each mesocosm tub was inserted in the ground and planted with the sedge Schoenoplectus tabernaemontani. The mesocosms were assigned to four hydrologic treatments involving two water depths and two hydraulic loading rates (HLRs). Nearby river water containing significant agricultural runoff was added weekly into a water feed tank system to provide weekly hydraulic loadings to the mesocosms. Inflow and outflow water samples from each wetland mesocosm were collected and analyzed for five species of nitrogen and phosphorus. By August 2019, 17 plant species, including the planted S. tabernaemontani, were present in the wetland mesocosms. The wetland mesocosms soon became nutrient sinks with average removal efficiencies of total phosphorus (TP) and total nitrogen (TN) of 38 ± 2.5% and 44 ± 1%, respectively, through the three-year experiment. The combination of a high HLR (30 cm week−1) and 10 cm of standing water achieved the best nitrogen removal efficiencies while highest phosphorus removal occurred with the combination of a high HLR (30 cm week−1) and no standing water.This paper discusses the following integrative findings:•Seasonal flooding had positive impacts on removal efficiency of NOx and a negative impact on the removal efficiency of TP and TKN.•No standing water resulted in a higher removal efficiency of TP and TKN than standing water, results consistent with previous studies.•Macrophyte plant community richness was influenced more by water depth than by hydraulic loading rate. Wetlands with 10 cm of standing water instead of saturated soils developed lower species richness but were more dominated by true wetland (OBL and FACW) species.•Study scale does matter. Annual nutrient accumulation rates in the mesocosms (1 m2) soils were lower than in the full-scale (10,000-m2) multi-year wetlands at the nearby Olentangy River Wetland Research Park (ORWRP) in central Ohio. Annual accumulation rates of phosphorus and nitrogen in the full-scale wetlands ranged from 3.3 to 3.5 g-P m−2 yr−1 and 16.4 to 19.5 g-N m−2 yr−1, while in our mesocosms, the annual rates ranged from 0.66 to 1.40 g-P m−2 yr−1 and 7.85 to 15.08 g-N m−2 yr−1. Our experimental wetland mesocosms could only function in the non-freezing months and have been in operation for only three years.

Nature-based shoreline protection by tidal marsh plants depends on trade-offs between avoidance and attenuation of hydrodynamic forces

In face of growing land-flooding and shoreline-erosion risks along coastal and estuarine shorelines, tidal marshes are increasingly proposed as part of nature-based protection strategies. While the effect of plant species traits on their capacity to attenuate waves and currents has been extensively studied, the effect of species traits on their capacity to cope with and grow under wave and current forces has received comparatively less attention. We studied the relationships between species zonation and the associated two-way interactions between species traits and hydrodynamics, by quantifying the effectiveness of avoidance and attenuation of hydrodynamic forces under field conditions. Measurements were done for two pioneer tidal marsh species in the brackish part of the Elbe estuary (Germany). Schoenoplectus tabernaemontani (S. tabernaemontani), which grows as a single stem without leaves and Bolboschoenus maritimus (B. maritimus) which grows as a triangular stem with multiple leaves. Our results reveal that S. tabernaemontani grows more seaward being exposed to stronger hydrodynamic forces than B. maritimus. The stems of S. tabernaemontani have, in comparison to B. maritimus, a lower flexural stiffness and less biomass, which decrease the experienced drag forces, thereby favoring its capacity to avoid hydrodynamic stress. At the same time, these plant traits which favor such avoidance capacity, were shown to also result in a lower capacity to attenuate waves and currents. Hence this implies that there are trade-offs between avoiding and attenuating hydrodynamic forces. Most efficient attenuation of waves and currents is thus only reached when species have the ability to grow under the prevailing hydrodynamic forces. Therefore, we argue that the two-way interaction between plants and hydrodynamics contributes to species zonation. The presence of this species zonation in turn enhances the overall efficiency of nature-based shoreline protection in pioneer tidal marshes.

Effects of resource heterogeneity and environmental disturbance on the growth performance and interspecific competition of wetland clonal plants

Resource heterogeneity significantly influences the growth, reproduction, and vegetation composition of wetland plants. However, the effect of the interaction of resource heterogeneity and environmental disturbance on growth performance and interspecific relationships among emergent plants is far from clear. In this study, we used a mesocosm experiment to examine the plasticity in clonal growth responses of Acorus calamus and Schoenoplectus tabernaemontani to different levels of flooding disturbance and soil sediment heterogeneity types. Soil nutrient heterogeneity treatments did not always have a positive effect on the growth of A. calamus and S. tabernaemontani because species-specific characteristics and environmental disturbance can influence the positive effect of environmental heterogeneity on clonal plants. A. calamus exhibited longer root length, behavior advantageous for heterogeneous distributions of nutrients. To adapt to deep water habitats, A. calamus and S. tabernaemontani transform clonal growth in the horizontal direction into the vertical direction. Soil nutrient heterogeneity can cause interspecific competition between A. calamus and S. tabernaemontani. However, with increasing water level, the effects of interspecific competition on S. tabernaemontani and A. calamus decreased gradually. The two wetland species compete for heterogeneously distributed soil nutrients under low water levels. However, an increase in water level results in limited illumination, so vertical growth is employed to compete for light resources. Our results show that S. tabernaemontani and A. calamus used both plasticity strategies to cope with resource heterogeneity and environmental disturbance. These spatial and temporal variations may modify growth and vegetation stability in disturbed environments.

Five macrocyclic glycosides from Schoenoplectus tabernaemontani

Macrocyclic glycosides with unique 22-membered dimeric lactone skeleton, are rare occurring natural products. There are only ten compounds reported so far. Herein we reported the isolation and characterisation of five macrocyclic glycosides from Schoenoplectus tabernaemontani, including three new compounds (Schoenopolide A-C, 1–3) and two known ones, Berchemolide (4) and Clemoarmanoside B (5). Their structures were established on the basis of extensive analysis of spectroscopic data. In addition, the anti-oxidative activity of Berchemolide (4) against H2O2-induced of renal tubular epithelial (HK-2) cells was also evaluated.

Urban wetland seed bank profiles in south-central New York State1,2

Wetlands are important habitats in urban landscapes that reduce flooding and improve water quality, yet urban wetland seed banks are rarely studied. Our main objective was to profile urban wetland seed banks in south-central New York. We exposed sediment cores from four wetlands in Broome County, New York, to flooded and drawdown treatments for 16 mo, and recorded community composition and seedling density. We found high spatial variation in species richness and seedling density among the four sites. Species richness ranged from 28 to 56 species, with sample-based extrapolation (Sest), Jackknife1, and Chao1 analyses estimating similar expected species richness values (Sest projected 37.9–77.0 species, Jackknife1 analysis estimated 40.5–77.8 species, and Chao1 projected 32.2–79.1 species). Mean seedling density ranged from 3,367 seedlings/m2 to 19,132 seedlings/m2. These seed banks were dominated by obligate wetland species (75.8–93.3%). Invasive species comprised a high percentage of seedlings for three wetlands (40.8–80.9%), but not for the fourth site (4.2%). Lythrum salicaria, Typha sp., and Ludwigia palustris were common species based on relative seedling density for three seed banks, while Leersia oryzoides, Schoenoplectus tabernaemontani, and Alisma triviale were common species in the fourth site. Similarity indices between the standing vegetation and their respective seed banks, based on presence/absence data, were low (13–34%). Species richness and seedling densities were within the ranges of natural wetland seed bank studies.

Response of seed reproduction of two dominant lakeside species to experimental warming in a typical plateau wetland in Northwestern Yunnan Plateau, China

Based on the forecasted warming scenarios by IPCC, we studied the impacts of warming (increased by 2.0 and 3.5 ℃) on seed reproduction of two lakeside dominant species (Schoeno-plectus tabernaemontani and Sparganium stoloniferum) in a typical plateau wetland (Napahai) in Northwestern Yunnan, by using "open-top chamber" technique. The results showed that warming had significant effects on the seed setting rate of both species, though with interspecific variation. The seed setting rate of S. tabernaemontani was significantly increased under two warming treatments, while that of S. stoloniferum was significantly decreased under the 2.0 ℃ warming treatment and had no variation under the 3.5 ℃ warming treatment. Warming promoted the spike growth of both species. For S. tabernaemontani, under the warming of 2.0 and 3.5 ℃ treatments, the spike length was increased by 82.9% and 89.0%, the spikelet number was increased by 133.3% and 150.0%, the biomass of each individual was increased by 10.1% and 89.6%, and the rate between biomass of per plant panicle and total biomass was increased by 79.5% and 409.3%, respectively. For S. stoloniferum, under the warming of 2.0 and 3.5 ℃ treatments, the spike length was increased by 66.1% and 95.2%, and the rate between biomass of per plant panicle and total biomass was increased by 878.8% and 1052.6%, respectively. Warming significantly increased seed yield of both species. Under the warming of 2.0 and 3.5 ℃ treatments, the seed yield per panicle of S. tabernaemontani was increased by 33.7% and 58.3%, respectively. For S. stoloniferum, the seed yield was increased by 3.4% and 69.5%, respectively. Under the warming of 2.0 and 3.5 ℃ treatments, the seed length of S. tabernaemontani was increased by 5.4% and 6.9%, and the seed length/width was increased by 9.1% and 5.3%, respectively. Warming had no significant effects on the seed shape of S. stoloniferum. The maximum and minimum temperatures were dominant factors affecting seed reproductions of both species. The advance of growing season, the prolonging of nutrition growing period, and accumulation of organic matter induced by warming would provide sufficient nutrient and energy accumulation for the reproduction and development of plants, which would promote seed reproduction capability of both species under the warming conditions.