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.

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.

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).

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.

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.

[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.

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.

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.

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.

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.

Influence of increased epicardial adipose tissue volume on 1-year in-stent restenosis in patients who received coronary stent implantation.

BACKGROUND: Epicardial adipose tissue (EAT) is significantly associated with the formation and composition of coronary atherosclerotic plaque, cardiac events and the clinical prognosis of coronary heart disease. But, whether increased EAT deposition may affect the incidence of in-stent restenosis (ISR) is currently unclear. This study used coronary computed tomography angiography (CCTA) as a mean to investigate whether increased EAT volume was associated with ISR. METHODS: A total of 364 patients who underwent 64-slice CCTA examination for the evaluation of suspected coronary artery disease, and subsequently underwent percutaneous coronary intervention (PCI) for the first time, and then accepted coronary angiography (CA) follow-up for ISR examination in one year, were retrospectively included in this study. EAT volume was measured by CCTA examination. CA follow-up was obtained between 9 and 15 months. ISR was defined as ≥ 50% luminal diameter narrowing of the stent segment or peri-stent segment. EAT volume was compared between patients with and without ISR and additional well-known predictors of ISR were compared. RESULTS: EAT volume was significantly increased in patients with ISR compared with those without ISR (154.5 ± 74.6 mL vs. 131.0 ± 52.2 mL, P < 0.001). The relation between ISR and EAT volume remained significant after adjustment for conventional cardiovascular risk factors and angiographic parameters. CONCLUSIONS: EAT volume was related with ISR and may provide additional information for future ISR.

Delayed reendothelialization with rapamycin is rescued by the addition of nicorandil in balloon-injured rat carotid arteries.

Rapamycin is an immunosuppressive agent that is added to drug eluting stents. It prevents restenosis, but it also impairs reendothelialization. Nicorandil is a hybrid agent with adenosine triphosphated (ATP)-sensitive K+ (KATP) channel opener and nitrate properties. It prevents oxidative stress and cell apoptosis induced by rapamycin in endothelial cells in vitro. However, whether nicorandil promotes reendothelialization after angioplasty delayed by rapamycin remains to be determined. Balloon injury model was established in SD rats. Nicorandil increased reendothelialization impaired by rapamycin, and it decreased xanthine oxidase (XO)-generated reactive oxygen species (ROS) induced by rapamycin. In addition, eNOS expression inhibited by rapamycin was increased by nicorandil in vivo. In vitro, rapamycin-impeded cardiac microvascular endothelial cells (CMECs) migration, proliferation and rapamycin-induced ROS production were reversed by nicorandil. Knockdown of XO partially inhibited rapamycin-induced ROS production and cell apoptosis in CMECs, and it promoted CMECs migration and proliferation suppressed by rapamycin. Knockdown of Akt partially prevents eNOS upregulation promoted by nicorandil. The beneficial effect of nicorandil is exhibited by inhibiting XO and up-regulating Akt pathway. Nicorandil combined with rapamycin in effect rescue the deficiencies of rapamycin alone in arterial healing after angioplasty.

[Pooled Umbilical Cord Blood Plasma for Culturing UCMSC and Ex Vivo Expanding Umbilical Cord Blood CD34⁺ Cells].

OBJECTIVE: To investigate the feasibility of umbilical cord blood plasma (UCP) as a replacement for fetal bovine serum (FBS) for culturing mesenchymal stem cells (MSC) derived from umbilical cord, and to observe the supporting effects of these cells (served as a feeder layer) on ex vivo expanding of human umbilical cord blood CD34(+) cells. METHODS: Umbilical cord blood (UCB) units were suitable if the Guangzhou cord blood bank donor selection criteria strictly were fulfilled. UCP were ready to use after the collection from the plasma depletion/reduction during the processing and pooling of suitable UCB units (at least 30 units were screened for pathogens and microorganisms, and qualified). Umbilical cord mesenchymal stem cells (UCMSC) were harvested from the umbilical cord tissue of health full-term newborns after delivery by enzyme digestion and divided into 3 groups: group 1 and 2 were cultured in the presence of DMEM/F12 containing either FBS or UCP; and group 3 was cultured in serum-free medium (StemPro® MSC SFM CTS™). Morphology, proliferation and surface marker expression were examined by flow cytometry, and the differentiation toward adipogenic and osteogenic lineages was used for investigating the effect of media on UCMSC after 3-5 passages. Next, the cells cultured in the three different media were cryopreserved and thawed, then prepared as feeder layers with the name of UCMSC(FBS), UCMSC(UCP), and UCMSC(SFM), respectively. The CD34⁺ cells were separated from UCB by magnetic activated cell sorting (MACS) and divided into 4 groups cultured in StemPro(-34) SFM medium added with hematopoietic cytokine combination (StemSpan® CC100). The control group included only CD34⁺ cells as group A (blank control) and experimental groups included UCMSC(FBS) + CD34⁺ cells as group B, UCMSC(UCP) + CD34⁺ cells as group C, UCMSC(SFM) + CD34⁺ cells as group D, and cells in all groups were cultured ex vivo for 7 days. The nucleated cell (NC) number was counted by cell counter, CD34⁺ cells were measured by flow cytometry, and clonogenic assay was conducted at day 0 and 7 of culture. The expansion efficiency was assessed. RESULTS: The morphology (spindle-shaped and plastic-adherent), the immunophenotype (high positive percentage of CD73, CD90, CD105 and CD166) and the differentiation potential (osteogenic and adipogenic) were almost indistinguishable among the cells cultured in any of these three media except for the expression of CD105 in group 3 (serum-free medium) was lower than that in other 2 groups (P < 0.05). UCMSC grown in UCP medium demonstrated significantly higher proliferation rates than that in media containing FBS or commercial serum-free supplement (P < 0.05). After co-culture for 7 days, the CD34⁺ cell percentage decreased in all the groups, while NC were amplified effectively and the CD34⁺ cell number increased with the same order as group C or D group B or A (control group) (P < 0.05). As compared with the colony-forming unit (CFU) number at day 0, there was no significant difference in the expansion multiple between group C and D, while the expansion of CFU in group C were higher than that in group B and A. CONCLUSION: The UCP can be used as a better animal-free serum supplement for growth, maintenance and differentiation of UCMSC, thus would be a safe choice for clinical-scale production of human MSC.

BK Virus-Associated Nephropathy with Plasma Cell-Rich Infiltrates Treated by Bortezomib-Based Regimen.

BK virus infection accompanied with plasma cell-rich infiltrates is a dilemma in renal transplant recipients. One young female patient diagnosed as BK virus-associated nephropathy with plasma cell-rich infiltrates at 16 months after renal transplant was treated with bortezomib and a sequential immuno-suppressive protocol of tacrolimus combined with leflunomide. After a short period of reduction, her serum creatinine increased slowly with stable BK viruria. The patient underwent repeat biopsy. The histologic changes showed a decrease in plasma cells and CD20+ cells in the allograft, but the other mononuclear cells showed no difference from the first biopsy. The immunosuppressive protocol was converted to tacrolimus combined with enteric-coated mycophenolate sodium. Her serum creatinine decreased gradually during 6 months of follow-up. We speculate that bortezomib can be used in BK virus-associated nephropathy accompanied with plasma cell-rich infiltrates, and this effect might be mediated through a decrease of plasma cells and CD20+ cells in the allograft. The dosage and time of therapy need to be explored in the future; additional studies of large samples are needed.

Recurrent Proliferative Glomerulonephritis With Monoclonal IgG Deposits After a Renal Transplant Which Was Insensitive to Pulse Therapy Remitted by Double Filtration Plasmapheresis.

Proliferative glomerulonephritis with monoclonal IgG deposits manifesting as a nephrotic syndrome recently has been described as a renal disease with the pathological features of mesangial and subendothelial deposits of monoclonal IgG. Eight cases of recurrent proliferative glomerulonephritis with monoclonal IgG deposits after a renal transplant have been reported. Almost all of these patients had a certain remission of proteinuria by steroids alone or with cyclophosphamide, and had further remission through other special treatments (ie, rituximab and plasmapheresis). We present a case of recurrent proliferative glomerulonephritis with monoclonal IgG deposits of the IgG3? subtype after a renal transplant, which was insensitive to pulse intravenous methyl-prednisolone and cyclophosphamide remitted by double filtration plasmapheresis. This case report reveals that recurrent proliferative glomerulo-nephritis with monoclonal IgG deposits may be insensitive to intravenous pulse therapy of methylprednisolone and cyclophosphamide. We advocate double filtration plasmapheresis as an effective treatment of proliferative glomerulo-nephritis with monoclonal IgG deposits on remission of proteinuria.

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.

Genetic structure in dwarf bamboo (Bashania fangiana) clonal populations with different genet ages.

Amplified fragment length polymorphism (AFLP) fingerprints were used to reveal genotypic diversity of dwarf bamboo (Bashania fangiana) clonal populations with two different genet ages (≤30 years versus >70 years) at Wolong National Natural Reserve, Sichuan province, China. We generated AFLP fingerprints for 96 leaf samples, collected at 30 m intervals in the two populations, using ten selective primer pairs. A total of 92 genotypes were identified from the both populations. The mean proportion of distinguishable genotypes (G/N) was 0.9583 (0.9375 to 0.9792) and Simpson's index of diversity (D) was 0.9982 (0.9973 to 0.9991). So, two B. fangiana populations were multiclonal and highly diverse. The largest single clone may occur over a distance of about 30 m. Our results demonstrated that the genotypic diversity and genet density of B. fangiana clonal population did not change significantly (47 versus 45) with genet aging and low partitioned genetic differentiation was between the two populations (Gst = 0.0571). The analysis of molecular variance consistently showed that a large proportion of the genetic variation (87.79%) existed among the individuals within populations, whereas only 12.21% were found among populations. In addition, the high level of genotypic diversity in the two populations implies that the further works were needed to investigate the reasons for the poor seed set in B. fangiana after flowering.