[Bioinformatics analysis and expression pattern of NAC transcription factor family of Angelica dahurica var. formosana from Sichuan province].

NAC(NAM/ATAF/CUC) protein plays an important role in plant growth and development, secondary cell wall formation and stress response. In this study, based on the sequencing data of Angelica dahurica, the NAC family was systematically analyzed using bioinformatics methods and its expression pattern was analyzed. Studies showed that 75 candidate genes had been selected from the NAC transcription factor family of A. dahurica, with the protein size of 148-641, all of which were unstable hydrophilic proteins. Most NAC proteins were localized in the nucleus, and had complete NAC domain. Phylogenetic analysis of NAC family proteins of A.dahurica and Arabidopsis thaliana showed that among the 17 subfamilies, NAC members were unevenly distributed in each subfamily, indicating that the evolution of species is developing in multiple directions. Among them, ANAC063 subfamily contained no NAC sequence of A. dahurica, which might be due to the functional evolution of the species. Analysis of protein transmembrane structure and signal peptide showed that NAC transcription factor could carry out transmembrane transportation, but its signal peptide function had not been found. Expression analysis showed that most transcription factors responded to abiotic stress and hormones to varying degrees, and the effects of hormones were obvious, especially ABA and IAA. In different organs of A. dahurica, most members of the NAC family had higher expression in root phloem, followed by root xylem. This study lays a foundation for further research on the function of A. dahurica NAC transcription factor and for solving the biological problems of A. dahurica.

Coronavirus disease 2019 in renal transplant recipients: Report of two cases.

Coronavirus disease 2019 (COVID-19) has been a pandemic worldwide. The data about COVID-19 in renal transplant recipient are deficiency. Herein, we report two COVID-19 cases in renal transplant recipients. Both cases were discharged following a treatment regimen including discontinued immunosuppressant and low-dose methylprednisolone-based therapy. There were no signs of rejection during the treatment. These successfully treated cases can provide helpful information about the management of COVID-19 in renal transplant recipients.

Clonal integration ameliorates the carbon accumulation capacity of a stoloniferous herb, Glechoma longituba, growing in heterogenous light conditions by facilitating nitrogen assimilation in the rhizosphere.

BACKGROUND AND AIMS: Enhanced availability of photosynthates increases nitrogen (N) mineralization and nitrification in the rhizosphere via rhizodeposition from plant roots. Under heterogeneous light conditions, photosynthates supplied by exposed ramets may promote N assimilation in the rhizosphere of shaded, connected ramets. This study was conducted to test this hypothesis. METHODS: Clonal fragments of the stoloniferous herb Glechoma longituba with two successive ramets were selected. Mother ramets were subjected to full sunlight and offspring ramets were subjected to 80 % shading, and the stolon between the two successive ramets was either severed or left intact. Measurements were taken of photosynthetic and growth parameters. The turnover of available soil N was determined together with the compostion of the rhizosphere microbial community. KEY RESULTS: The microbial community composition in the rhizosphere of shaded offspring ramets was significantly altered by clonal integration. Positive effects of clonal integration were observed on NAGase activity, net soil N mineralization rate and net soil N nitrification rate. Increased leaf N and chlorophyll content as well as leaf N allocation to the photosynthetic machinery improved the photosynthetic capability of shaded offspring ramets when the stolon was left intact. Clonal integration improved the growth performance of shaded, connected offspring ramets and whole clonal fragments without any cost to the exposed mother ramets. CONCLUSIONS: Considerable differences in microbial community composition caused by clonal integration may facilitate N assimilation in the rhizosphere of shaded offspring ramets. Increased N content in the photosynthetic machinery may allow pre-acclimation to high light conditions for shaded offspring ramets, thus promoting opportunistic light capture. In accordance with the theory of the division of labour, it is suggested that clonal integration may ameliorate the carbon assimilation capacity of clonal plants, thus improving their fitness in temporally and spatially heterogeneous habitats.

Effect of an Airbag-selective Portal Vein Blood Arrester on the Liver after Hepatectomy: A New Technique for Selective Clamping of the Portal Vein.

OBJECTIVE: A novel technique was explored using an airbag-selective portal vein blood arrester that circumvents the need for an intraoperative assessment of anatomical variations in patients with complex intrahepatic space-occupying lesions. METHODS: Rabbits undergoing hepatectomy were randomly assigned to 4 groups: intermittent portal triad clamping (PTC), intermittent portal vein clamping (PVC), intermittent portal vein blocker with an airbag-selective portal vein blood arrester (APC), and without portal blood occlusion (control). Hepatic ischemia and reperfusion injury were assessed by measuring the 7-day survival rate, blood loss, liver function, hepatic pathology, hepatic inflammatory cytokine infiltration, hepatic malondialdehyde levels, and proliferating cell nuclear antigen levels. RESULTS: Liver damage was substantially reduced in the APC and PVC groups. The APC animals exhibited transaminase levels similar to or less oxidative stress damage and inflammatory hepatocellular injury compared to those exhibited by the PVC animals. Bleeding was significantly higher in the control group than in the other groups. The APC group had less bleeding than the PVC group because of the avoidance of portal vein skeletonization during hepatectomy. Thus, more operative time was saved in the APC group than in the PVC group. Moreover, the total 7-day survival rate in the APC group was higher than that in the PTC group. CONCLUSION: Airbag-selective portal vein blood arresters may help protect against hepatic ischemia and reperfusion injury in rabbits undergoing partial hepatectomy. This technique may also help prevent liver damage in patients requiring hepatectomy.

Clonal integration of stress signal induces morphological and physiological response of root within clonal network.

Clonal integration of defense or stress signal induced systemic resistance in leaf of interconnected ramets. However, similar effects of stress signal in root are poorly understood within clonal network. Clonal fragments of Centella asiaticas with first-young, second-mature, third-old and fourth-oldest ramets were used to investigate transportation or sharing of stress signal among interconnected ramets suffering from low water availability. Compared with control, oxidative stress in root of the first-young, second-mature and third-old ramets was significantly alleviated by exogenous ABA application to the fourth-oldest ramets as well as enhancement of antioxidant enzyme (SOD, POD, CAT and APX) activities and osmoregulation ability. Surface area and volume in root of the first-young ramets were significantly increased and total length in root of the third-old ramets was significantly decreased. POD activity in root of the fourth-oldest and third-old ramets was significantly enhanced by exogenous ABA application to the first-young ramets. Meanwhile, total length and surface area in root of the fourth-oldest and third-old ramets were significantly decreased. Ratio of belowground to aboveground biomass in the whole clonal fragments was significantly increased by exogenous ABA application to the fourth-oldest or first-young ramets. It is suggested that transportation or sharing of stress signal may induce systemic resistance in root of interconnected ramets. Specially, transportation or sharing of stress signal against phloem flow was observed in the experiment. Possible explanation is that rapid recovery of foliar photosynthesis in first-young ramets subjected to exogenous ABA application can partially reverse phloem flow within clonal network. Thus, our experiment provides insight into ecological implication on clonal integration of stress signal.

Treatment with exogenous hydrogen sulfide attenuates hyperoxia-induced acute lung injury in mice.

The aim of this work was to test the effect of treatment with hydrogen sulfide (H2S) on hyperoxia-induced acute lung injury in mice. Mice were exposed to room air or 95 % O2, and treated with NaHS (intraperitoneal injection of 0.1 ml/kg/day of 0.56 mol/l NaHS). Treatment with H2S partly restored the reduced H2S levels in plasma and lungs of mice exposed to hyperoxia. Treatment with H2S attenuated hyperoxia-induced acute lung injury marked by reduced ratio of lung weight to body weight, ratio of lung wet weight to dry weight, and cell numbers and protein content in bronchoalveolar lavage (BAL) and decreased apoptosis. Treatment with H2S markedly prolonged the survival of mice under oxygen exposure. Treatment with H2S abated hyperoxia-induced oxidative stress marked by reduced malondialdehyde and peroxynitrite formation, reduced NADPH oxidase activity, enhanced translocation of nuclear factor E2-related factor (Nrf2) into nucleus and increased activity of HO-1. Treatment with H2S decreased IL-1ß, MCP-1, and MIP-2, and increased IL-10 expression in lungs of mice exposed to hyperoxia. Treatment with H2S decreased NFκB activity and iNOS expression in lungs, and reduced NOx content in BAL of mice exposed to hyperoxia. Treatment with H2S reduced lung permeability and suppressed VEGF release and VEGFR2 expression in lungs of mice under oxygen exposure. Treatment with exogenous H2S attenuated hyperoxia-induced acute lung injury through abating oxidative stress, suppressing inflammation, and reducing lung permeability in mice.

Timing of systemic resistance induced by local exogenous ABA application within clonal network of stoloniferous herb Centella asiatica subjected to low water availability.

Resistance traits of plants can be activated both at the damaged site and undamaged parts. Systemic resistance induced by local exogenous abscisic acid (ABA) application alleviated negative effect of low water availability on growth performance of clonal plant. However, timing of systemic resistance was poorly understood. Timing of systemic resistance refers to its activation and decay time within clonal network. Clonal fragment of Centella asiatica with four successive ramets (including first-oldest, second-older, third-old and fourth-young ramets) subjected to low water availability (20% soil moisture content) was used to explore effects of local exogenous ABA application on the timing of resistance activation and decay. Systemic resistance activated by local exogenous ABA application after 4 days remained at least 28 days. Compared with control, biomass accumulation of whole clonal fragment, root biomass and ratio of belowground to aboveground biomass significantly increased by local exogenous ABA application after 28 days. It is suggested that rapid activation and delay of resistance response induced by local exogenous ABA application within clonal network may improve fitness of clonal plant subjected to abiotic stress.

Clinical significance of decreased nidogen-2 expression in the tumor tissue and serum of patients with hepatocellular carcinoma.

BACKGROUND AND OBJECTIVES: Nidogen-2 is a ubiquitous component of basement membrane (BM), which is modified by tumor cells to facilitate tumor invasion. However, the expression and function of nidogen-2 in hepatocellular carcinoma (HCC) remains unknown at present. In this study, we sought to investigate the potential role of nidogen-2 in HCC. METHODS: Nidogen-2 expression in HCC tissues, cell lines, and serum was evaluated by immunohistochemistry, immunoassay, and real-time PCR assays. The regulation of nidogen-2 expression was investigated using doxycycline induction and small interfering RNA analyses. RESULTS: Nidogen-2 was significantly decreased in both HCC tissues and serum (P < 0.001). The decreased expression of nidogen-2 in HCC tissues was significantly correlated with tumor progression factors (P < 0.05). Inhibition of matrix metalloproteinase (MMP)-9 led to significantly upregulate nidogen-2 expression in vitro assays. Moreover, patients with HCC had lowest serum nidogen-2 levels compared with patients with benign liver diseases and normal volunteers. Furthermore, the receiver operating characteristic curve analysis revealed a good diagnostic performance of nidogen-2 for HCC. CONCLUSIONS: These findings suggest that decreased expression of nidogen-2 may have a potential pathogenetic role in the development of HCC and may also have potential diagnostic value for HCC.

Clonal integration benefits an invader in heterogeneous environments with reciprocal patchiness of resources, but not its native congener.

Many of the world's most invasive plants are clonal, and clonal functional traits are suggested to contribute to their invasiveness. Clonal integration is one of the most important clonal functional traits, but it is still unclear whether clonal integration can benefit invasive alien clonal plants more than native ones in heterogeneous environments with reciprocal patchiness of resources and whether invasive plants show a higher capacity of division of labor than native ones in such environments. We grew connected (allowing clonal integration) and disconnected (preventing clonal integration) ramet pairs of an invasive plant Wedelia trilobata and its occurring native congener W. chinensis in the environment consisting of reciprocal patches of light and soil nutrients (i.e., a high-light but low-nutrient patch and a low-light but high-nutrient patch). Clonal integration greatly promoted the growth of the invasive species, but had no significant effect on the native one. Both invasive and native species showed division of labor in terms of morphology, biomass allocation, and/or photosynthetic physiology, but the capacity of labor division did not differ between the invasive and the native species. We conclude that in heterogeneous environments consisting of reciprocal patches of resources, which are common in nature, clonal integration can confer invasive plants a competitive advantage over natives, but this difference is not related to their capacity of labor division. This study highlights the importance of clonal integration for plants in heterogeneous environments and suggests that clonal integration can contribute to the invasion success of alien clonal plants.

Effects of nutrient supply on leaf stoichiometry and relative growth rate of three stoloniferous alien plants.

Different nutrient supply brings about changes in leaf stoichiometry, which may affect growth rate and primary production of plants. Invasion of alien plants is a severe threat to biodiversity and ecosystem worldwide. A pot experiment was conducted by using three stoloniferous alien plants Wedelia trilobata, Alternanther philoxeroides and Hydrocotyle vulgaris to investigate effects of nutrient supply on their leaf stoichiometry and relative growth rate. Different nitrogen or phosphorus supply was applied in the experiment (N1:1 mmol L-1, N2:4 mmol L-1, and N3:8 mmol L-1, P1:0.15 mmol L-1, P2:0.6 mmol L-1 and P3:1.2 mmol L-1). Nitrogen and phosphorus concentrations in leaves of the three alien plants significantly increased with increase of nitrogen supply. With increase of phosphorus supply, nitrogen or phosphorus concentration of leaf was complex among the three alien plants. N:P ratio in leaf of the three alien plants subjected to different levels of nutrient supply was various. A positive correlation between relative growth rate and N:P ratio of the leaf is observed in W. trilobata and A. philoxeroides suffering from N-limitation. A similar pattern was not observed in Hydrocotyle vulgaris. We tentatively concluded that correlations between relative growth rate and N: P ratio of the leaf could be affected by species as well as nutrient supply. It is suggested that human activities, invasive history, local abundance of species et al maybe play an important role in the invasion of alien plants as well as relative growth rate.

Soil heterogeneity in the horizontal distribution of microplastics influences productivity and species composition of plant communities.

Contamination of soils by microplastics can have profound ecological impacts on terrestrial ecosystems and has received increasing attention. However, few studies have considered the impacts of soil microplastics on plant communities and none has tested the impacts of spatial heterogeneity in the horizontal distribution of microplastics in the soil on plant communities. We grew experimental plant communities in soils with either a homogeneous or a heterogeneous distribution of each of six common microplastics, i.e., polystyrene foam (EPS), polyethylene fiber (PET), polyethylene bead (HDPE), polypropylene fiber (PP), polylactic bead (PLA) and polyamide bead (PA6). The heterogeneous treatment consisted of two soil patches without microplastics and two with a higher (0.2%) concentration of microplastics, and the homogeneous treatment consisted of four patches all with a lower (0.1%) concentration of microplastics. Thus, the total amounts of microplastics in the soils were exactly the same in the two treatments. Total and root biomass of the plant communities were significantly higher in the homogeneous than in the heterogeneous treatment when the microplastic was PET and PP, smaller when it was PLA, but not different when it was EPS, HDPE or PA6. In the heterogeneous treatment, total and root biomass were significantly smaller in the patches with than without microplastics when the microplastic was EPS, but greater when the microplastic was PET or PP. Additionally, in the heterogeneous treatment, root biomass was significantly smaller in the patches with than without microplastics when the microplastic was HDPE, and shoot biomass was also significantly smaller when the microplastic was EPS or PET. The heterogeneous distribution of EPS in the soil significantly decreased community evenness, but the heterogeneous distribution of PET increased it. We conclude that soil heterogeneity in the horizontal distribution of microplastics can influence productivity and species composition of plant communities, but such an effect varies depending on microplastic chemical composition (types) and morphology (shapes).

Indication of the expression of transgene in rice plant based on hyperspectral remote sensing technique II--growth monitoring of samples in the contrast experiment.

Since the complication of monitoring and evaluating the problems about the transgenic expression and its impacts on the receptor in the transgenic crop breeding and other relevant evaluated works, the authors in the present work tried to assess the differences of spectral parameters of the transgenic rice in contrast with its parent group quantitatively and qualitatively, fulfilling the growth monitoring of the transgenic samples. The spectral parameters (spectral morphological characteristics and indices) chosen are highly related to internal or external stresses to the receipts, and thus could be applied as indicators of biophysical or biochemical processes changes of plant. By ASD portable field spectroradiometer with high-density probe, fine foliar spectra of 8 groups were obtained. By analyzing spectral angle and continuum removal, the spectral morphological differences and their locations of sample spectra were found which could be as auxiliary priori knowledge for quantitative analysis. By investigating spectral indices of the samples, the quantitative differences of spectra were revealed about foliar chlorophyll a+b and carotenoid content. In this study both the spectral differences between transgenic and parent groups and among transgenic groups were investigated. The results show that hyperspectral technique is promising and a helpful auxiliary tool in the study of monitoring the transgenic crop and other relevant researches. By this technique, quantitative and qualitative results of sample spectra could be provided as prior knowledge, as certain orientation, for laboratory professional advanced transgenic breeding study.

Distinct responses of frond and root to increasing nutrient availability in a floating clonal plant.

Current knowledge on responses of aquatic clonal plants to resource availability is largely based on studies manipulating limited resource levels, which may have failed to capture the "big picture" for aquatic clonal plants in response to resource availability. In a greenhouse experiment, we grew the floating clonal plant Spirodela polyrhiza under ten nutrient levels (i.e., 1/64×, 1/32×, 1/16×, 1/8×, 1/4×, 1/2×, 1×, 2×, 4× and 8×full-strength Hoagland solution) and examined their responses in terms of clonal growth, morphology and biomass allocations. The responses of total biomass and number of ramets to nutrient availability were unimodal. A similar pattern was found for frond mass, frond length and frond width, even though area per frond and specific frond area fluctuated greatly in response to nutrient availability. In contrast, the responses of root mass and root length to nutrient availability were U-shaped. Moreover, S. polyrhiza invested more to roots under lower nutrient concentrations. These results suggest that nutrient availability may have distinct influences on roots and fronds of the aquatic clonal plant S. polyrhiza, resulting in a great influence on the whole S. polyrhiza population.

Imbalance of matrix metalloproteinases/tissue inhibitor of metalloproteinase-1 and loss of fibronectin expression in patients with congestive heart failure.

OBJECTIVE: Previous studies have demonstrated that an imbalance of matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinase-1 (TIMP-1) and a loss of fibronectin are associated with postmyocardial infarction remodeling in rats. The present study was designed to examine this issue in patients with congestive heart failure (CHF). METHODS: We measured plasma levels and the cardiac protein expression of MMPs/TIMP-1 and fibronectin in 39 patients with CHF and 38 controls. RESULTS: Plasma levels of MMP-2, MMP-3, and MMP-9 tended to be higher in patients with CHF (NYHA II: 276 +/- 18, 613 +/- 118, and 245 +/- 43 microg/l, respectively; NYHA III: 302 +/- 20, 850 +/- 132, and 310 +/- 39 microg/l, respectively; NYHA IV: 367 +/- 15, 998 +/- 99, and 392 +/- 27 microg/l, respectively) than in controls (213 +/- 23, 485 +/- 102, and 158 +/- 31 microg/l, respectively), while the plasma TIMP-1 level tended to be lower in patients with CHF (NYHA II: 126 +/- 12 microg/l, NYHA III: 83 +/- 11 microg/l, and NYHA IV: 61 +/- 12 microg/l) than in controls (208 +/- 15 microg/l). Interestingly, the changes in protein expression of MMPs/TIMP-1 were consistent with their plasma concentration. Furthermore, the fibronectin level in the patients with CHF was significantly lower than in the controls. CONCLUSIONS: These data suggest that human CHF is associated with an imbalance of MMPs/TIMP-1 and a concurrent loss of fibronectin.

[Clinicopathological features and surgical treatment of large hepatocellular carcinoma].

OBJECTIVE: To investigate the clinicopathological features and the safety of surgical treatment of large hepatocellular carcinoma (HCC). METHODS: A total of 316 HCC patients undergoing hepatectomy at our hospital from December 2005 to December 2008 were divided into HCC > 10 cm (large HCC) group (n = 119) and HCC < or = 10 cm group (n = 197). The clinicopathological data and surgical outcomes were compared between two groups. RESULTS: The HCC > 10 cm group had a higher rate of symptoms and physical findings than the HCC < or = 10 cm group. Compared with HCC < or = 10 cm group, intrahepatic metastasis, vascular invasion, adjacent organ invasion and poorly differentiated tumor were more common in HCC > 10 cm group. The preoperative serum levels of alpha-fetoprotein, aspartate aminotransferase and alkaline phosphatase were higher in HCC > 10 cm group. The patients with HCC > 10 cm received more major hepatectomies, suffered more intraoperative blood loss, had greater blood transfusion requirements and needed a longer operative duration. However, the incidences of postoperative complications and mortality rate were similar in two groups. CONCLUSION: Large HCC is characterized by more clinical manifestations, higher incidences of vascular invasion and adjacent organ invasion, and worse histological grades. Surgical resection for large HCC is both safe and feasible.

[Detection of the expression of transgene in rice plant based on hyperspectral remote sensing technique].

The present study aims to identify the expression of transgene in given rice plant samples in certain conditions. To avoid external noise caused by temperature change and water-loss, field spectrum was collected with ASD field spectrometer in natural state. The study calculated the mean spectrum of samples as main data set analyzed which were controlled by inner clustering coefficient to ensure data quality. By mean spectrum, the noise from random distinctions in few individual cultivators, which could not be expressed in the class stably, could be weakened even with filtering. With the help of parameters, such as red edge and green peak, this study gave qualitative spectral differences between transgenic samples and their parents. The results show that the transgenes in rice plant were expressed and influenced the samples. Moreover, it was found that the parameters of area are more suitable for describing the differences/changes of the samples, while PRI and SR-PRI are more sensitive to indicate them. Most of the above results could be found on the continuum-removal spectrum curve of samples. These conclusive results demonstrate that hyperspectral remote sensing technique has good prospects and application potential in transgene expression detection and monitoring, especially in plant breeding process.

Therapeutic effects of Co-Venenum Bufonis Oral Liquid on radiation-induced esophagitis in rats.

To investigate the effects of Co-Venenum Bufonis Oral Liquid (cVBOL) on radiation-induced esophagitis in rats. Irradiation (30 Gy) with X-RAD 225 x-ray was applied to induce esophagitis in 64 Wistar rats and treated by different methods. The body weight of rats either in RT group, cVBOL+RT, or EM+RT group was significantly decreased when compared with that in normal group (P<0.0001). After irradiation, histopathological studies, immunohistochemistry, and MRI scanning on esophagus were performed. Serum TNF-α,IL-6 and IL-10 were also determined by ELISA at 7, 14, 21 and 28 days after radiation treatment. The results demonstrated that radiation caused esophageal injury and thickening of esophageal tissue layers. The esophageal tissues after radiation treatment showed typical pathological changes of esophagitis. Radiation also caused esophagus edema. Treatment of cVBOL reduced the severity of histological esophageal lesion, decreased the expression of bFGF and TGF-ß1, and lowered serum levels of inflammatory cytokines including TNF-α, IL-6 and IL-10 over 28 days after radiation treatment. In conclusion, cVBOL treatment is effective to prevent radiation induced esophagitis and reduces radiation induced esophagitis may be mediated through its ant-inflammatory effects.

Growth and Morphological Responses of Duckweed to Clonal Fragmentation, Nutrient Availability, and Population Density.

Connected ramets of aquatic clonal plants are susceptible to fragmentation by disturbance. Such clonal fragmentation may interact with nutrient availability and individual density to affect growth and morphology of aquatic clonal plants. We grew the widespread floating clonal plant Spirodela polyrhiza (duckweed) under three levels of population density (low, medium, or high), two levels of nutrient availability (low or high), and two levels of clonal fragmentation (with or without). Clonal fragmentation and high nutrients increased biomass and ramet number, but decreased frond width, frond length, and specific frond area of S. polyrhiza. Increasing population density decreased growth (biomass and ramet number) and frond and root size, and increased frond thickness of individual ramets of S. polyrhiza. The negative effect of population density on growth of S. polyrhiza was greater under high than under low nutrient availability. Furthermore, the negative effect of population density on total mass and frond mass of S. polyrhiza was greater with fragmentation than without. These results suggest that clonal fragmentation, nutrient availability and population density can interact to affect growth and morphology of clonal floating plants. Competition for nutrients and space, rather than light, may be the mechanisms underlying reduced growth of clonal floating plants. As clonal fragmentation can increase biomass and ramet production of S. polyrhiza, disturbance that potentially causes clonal fragmentation cannot be recommended as a measure to limit the spread of clonal floating plants.

Physical space interacts with clonal fragmentation and nutrient availability to affect the growth of Salvinia natans.

Physical space, clonal fragmentation and nutrient availability can each affect the growth of clonal plants, but their interactive effect has been little studied. We grew un-fragmented (connected) and fragmented (disconnected) ramet pairs of the floating, clonal plant Salvinia natans in cylindrical containers with different diameters and heights (volumes) filled with solutions of two nutrient levels (high vs. low). To simulate competition environments that are commonly confronted by S. natans, we also added two ramets of another floating plants Spirodela polyrrhiza in each container. Biomass (total biomass, floating biomass and submerged biomass) and number of ramets of S. salvinia were higher in the containers with a larger diameter. Compared to the low nutrient level, the high nutrient level increased number of ramets, and altered submerged to floating mass ratio of S. salvinia. The impacts of physical space on floating mass and number of ramets were stronger under the high than under the low nutrient level. Clonal fragmentation positively affected biomass in the containers with a smaller volume (a smaller height and diameter), but had little impact in the containers with a larger volume (a larger height or diameter). Our results suggest that physical space can interact with nutrients and clonal fragmentation to affect the performance of S. salvinia under competition.