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Abstract Allochthonous (e.g., riparian) plant litter is among the organic matter resources that are important for wetland ecosystems. A compact canopy of free‐floating vegetation on the water surface may allow for riparian litter to remain on it for a period of time before sinking to the bottom. Thus, we hypothesized that canopy of free‐floating vegetation may slow decomposition processes in wetlands. To test the hypothesis that the retention of riparian leaf litter on the free‐floating vegetation in wetlands affects their subsequent decomposition on the bottom of wetlands, a 50‐day in situ decomposition experiment was performed in a wetland pond in subtropical China, in which litter bags of single species with fine (0.5 mm) or coarse (2.0 mm) mesh sizes were placed on free‐floating vegetation (dominated by Eichhornia crassipes, Lemna minor, and Salvinia molesta) for 25 days and then moved to the pond bottom for another 25 days or remained on the pond bottom for 50 days. The leaf litter was collected from three riparian species, that is, Cinnamomum camphora, Diospyros kaki, and Phyllostachys propinqua. The retention of riparian leaf litter on free‐floating vegetation had significant negative effect on the carbon loss, marginal negative effects on the mass loss, and no effect on the nitrogen loss from leaf litter, partially supporting the hypothesis. Similarly, the mass and carbon losses from leaf litter decomposing on the pond bottom for the first 25 days of the experiment were greater than those from the litter decomposing on free‐floating vegetation. Our results highlight that in wetlands, free‐floating vegetation could play a vital role in litter decomposition, which is linked to the regulation of nutrient cycling in ecosystems.

Abstract Examining the coordination of leaf and fine root traits not only aids a better understanding of plant ecological strategies from a whole‐plant perspective, but also helps improve the prediction of belowground properties from aboveground traits. The relationships between leaf and fine root traits have been extensively explored at global and regional scales, but remain unclear at local scales. Here, we measured six pairs of analogous leaf and fine root traits related to resource economy and organ size for coexisting dominant and subordinate vascular plants at three successional stages of temperate forest swamps in Lingfeng National Nature Reserve in the Greater Hinggan Mountains, NE China. Leaf and fine root traits related to resource acquisition (e.g., specific leaf area [SLA], leaf N, leaf P, root water content, and root P) decreased with succession. Overall, we found strong linear relationships between leaf dry matter content (LDMC) and root water content, and between leaf and root C, N, and P concentrations, but only weak correlations were observed between leaf area and root diameter, and between SLA and specific root length (SRL). The strong relationships between LDMC and root water content and between leaf and root C, N, and P held at the early and late stages, but disappeared at the middle stage. Besides, C and P of leaves were significantly correlated with those of roots for woody plants, while strong linkages existed between LDMC and root water content and between leaf N and root N for herbaceous species. These results provided evidence for the existence of strong coordination between leaf and root traits at the local scale. Meanwhile, the leaf–root trait relationships could be modulated by successional stage and growth form, indicating the complexity of coordination of aboveground and belowground traits at the local scale.

Plant functional composition, defined by both community-weighted mean (CWM) traits and functional diversity, can provide insights into plant ecological strategies and community assembly. However, our understanding of plant functional composition during succession is largely based on aboveground traits. Here we investigated community-level traits and functional diversity for six pairs of analogous leaf and fine root traits of understory plants in a temperate forest swamp during succession with a decrease in soil pH and nutrient availability. CWMs of traits related to resource acquisition (including specific leaf area, specific root length, leaf N, leaf P, root N, and root P) decreased with succession, whereas those related to resource conservation (leaf dry matter content, root dry matter content, leaf tissue density, leaf C, and root C) increased along the forest swamp successional gradient. Multi-trait functional dispersion (FDis) of both leaf and fine root traits tended to decrease along the successional gradient, but functional richness and evenness were highest at the middle successional stage. Moreover, FDis of individual plant traits except N showed the same pattern as multi-trait FDis. Soil pH and nutrient availability were the main drivers of successional changes in both CWM traits and FDis. The changes of community-level traits along succession indicated a shift from acquisitive to conservative strategy of understory plants during forest swamp succession. Similar trends in leaf and fine root functional diversity along succession may indicate above- and belowground functional diversity are coordinated during the processes of plant community assembly. These findings of linkages between above- and belowground plant functional composition have important implications for plant community dynamics and assembly rules.

AIM: To investigate and analyze the changes of corneal biomechanics of normal eyes, forme frusta keratoconus eyes, subclinical keratoconus eyes and clinical keratoconus eyes by Corneal visualization Scheimpflug technology(Corvis ST), and provide clinical basis for early diagnosis of keratoconus. METHODS: Case-control study. We randomly selected 40 normal eyes as normal group, 15 forme frusta keratoconus eyes as forme frusta keratoconus group, 23 subclinical keratoconus eyes as subclinical keratoconus group, and 40 clinical keratoconus eyes as keratoconus group. The biomechanical parameters of each group were measured by Corvis ST. The receiver operating characteristic(ROC)curves was plotted to distinguish keratoconus from the normal cornea. RESULTS: There was no significant difference in the parameters of biomechanics between normal group and forme frusta keratoconus group (P>0.05). Compared to normal group and subclinical keratoconus group, the parameters second applanation length(AL2), first velocity of applanation(AV1), central curvature radius at highest concavity(HC-radius), deformation amplitude(DA)were revealed statistically significant differences(PCONCLUSION: The corneal biomechanical parameters of forme frusta keratoconus group are not changed compared with normal group. The changes between normal group and subclinical keratoconus group should combine with other technology to further improve subclinical keratoconic screening. Compared with normal corneas, keratoconus has a great change in biomechanics, which DA diagnosis of the highest efficiency.

The as-cast and annealed mechanical properties of 00Cr18Nb ferritic stainless steel prepared by investment casting process were studied. Experimental results indicated that the problem of unstable plastic fluctuations in the as-cast state can be effectively solved by annealing treatment. The plasticity of the investment-cast 00Cr18Nb steel after annealing at 800 and 850 °C was more stable than that of 900 °C. It showed that the optimum annealing condition was 850 °C for 2 h with the appropriate elongation and tensile strength of 26.3 ± 0.4% and 513 ± 4 MPa, respectively. The main reason for annealing to improve plasticity is the Laves phase in the microstructure, which has better effects on mechanical properties than (Ti,Nb)(C,N) particles and grain size. With the increase of annealing temperature and time, the size of Laves phase tended to increase. The size, quantity, morphology and distribution of Laves phase after annealing are closely related to the mechanical properties. The Laves phase with a large amount of uniform distribution in the form of small particles can effectively improve the mechanical properties after annealing treatment.

AIM: To demonstrate the changes in ultrastructure and histopathology of the cornea in acute corneal alkaline burns after femtosecond laser-assisted deep lamellar keratoplasty. METHODS: The New Zealand white rabbits treated with alkaline corneal burn were randomized into two groups, Group A (16 eyes) with femtosecond laser-assisted deep lamellar keratoplasty 24h after burn and Group B (16 eyes) without keratoplasty as controls. All eyes were evaluated with transmission electron microscopy (TEM) at 1, 2, 3, and 4wk follow-up, then all corneas were tested by hematoxylin and eosin staining histology. RESULTS: The corneal grafts in Group A were transparent, while those in Group B showed corneal stromal edema and loosely arranged collagen fibers. One week after treatment, TEM revealed the intercellular desmosomes in the epithelial layers and intact non-dissolving nuclei in Group A. At week 4, the center of the corneas in Group A was transparent with regularly arranged collagen fibers and fibroblasts in the stroma. In Group B, squamous cells were observed on the corneal surface and some epithelial cells were detached. CONCLUSION: Femtosecond laser-assisted deep lamellar keratoplasty can suppress inflammatory responses, prevent toxic substance-induced injury to the corneal endothelium and inner tissues with quicker recovery and better visual outcomes.

This study was the first report about the complete chloroplast genome of Aster hersileoides (Asteraceae, Astereae). The circular whole cp genome of A. hersileoides was 152,345 bp in length, contained a large single copy (LSC) region of 84,124 bp and a small single copy (SSC) region of 18,243 bp. These two regions were separated by a pair of inverted repeat regions (IRa and IRb), each of them 24,989 bp in length. A total of 134 functional genes were encoded, consisted of 89 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The overall GC content of the chloroplast genome sequence was 37.3% and the GC contents of the LSC, SSC, and IR regions were 32.6, 31.2, and 43.0%, respectively. The phylogenetic hypotheses obtained based on the analyses of 20 cp genomes places A. hersileoides within the tribe Astereae of Asteraceae.

AIM: To evaluate the visual quality between femtosecond laser small incision lenticule extraction(SMILE)and femtosecond laser in situ keratomileusis(LASIK)in the treatment of myopia. METHODS: This study comprised 22 eyes(11 patients)underwent SMILE and 43 eyes(23 patients)received LASIK with femtosecond laser to correct myopia and myopic astigmatism. The two groups were recorded bydouble-pass optical quality analysis system(OQAS)at preoperative and postoperative 1mo. The two groups were compared: modulation transfer function cutoff frequency(MTF cutoff), strehl ratio(SR), objective scattering index(OSI). The early visual quality after operation between two groups were analyzed and evaluated.RESULTS: The MTF cutoff after operation one month were 34.835±10.113c/deg(SMILE group)and 38.362±10.623c/deg(LASIK group)(t=0.925, P=0.362). The SR after operation one month were 0.204±0.077(SMILE group)and 0.218±0.072(LASIK group)(t=0.557, P=0.582). The OSI after operation one month were 0.608±0.291(SMILE group)and 0.545±0.405(LASIK group)(t=-0.473, P=0.640). CONCLUSION: The double-pass OQAS tell us that there was not statistically significant between femtosecond laser SMILE and femtosecond LASIK in the treatment of myopia.

AIM: To compare the postoperative visual outcomes of VisuMax small incision lenticule extraction(SMILE)and femtosecond laser assisted LASIK(FEMTO LASIK)for myopia. METHODS:Eighty-tree eyes(42 patients)underwent VisuMax SMILE and 94 eyes(47 patients)received FEMTO LASIK to correct myopia were comprised. The safety, efficacy, predictability, stability and adverse events were assessed preoperatively and 1d, 1 week, 1 month, 3 months postoperatively. RESULTS: At 3 months, the mean safety index was 1.10±0.16 in the SMILE group and 1.09±0.16 in the FEMTO LASIK group; the mean efficacy index was respectively 1.10±0.16 and 1.08±0.12; Spherical equivalent(SE)was respectively 0.11±0.23D and 0.08±0.25D within ±1.00D of the targeted SE correction in 82 eyes(98.8%)of the SMILE group and 91 eyes(96.8%)of the FEMTO LASIK group and SE within ±0.50D in 73 eyes(88.0%)of the SMILE group and 78 eyes(83.0%)of the FEMTO LASIK group. There were no significant complications in both groups. CONCLUSION: SMILE and FEMTO LASIK have equal safety, efficacy, predictabilityand stability in the treatment of myopia.

AIM: To observe the predictability of corneal flap creation with the VisuMax femtosecond laser and preliminarily analyze the factors correlated to the thickness and diameter of the flap. METHODS: This retrospective case series study included 300 eyes of 150 consecutive patients. The eyes were assigned to two groups according to intended flap thickness, 100μm(204 eyes)and 110μm(96 eyes), which created with the VisuMax femtosecond laser. Intended flap diameters were 7.9mm and 8.3mm. Difference analysis of flap diameter and intended diameter as well as flap thickness and intended thickness were made. The data were analyzed with SPSS to sum up a multiple stepwise regression formula that could express their quantitative relationship. RESULTS: The 100μm flap group had an average flap thickness of 103.11±4.07μm, while for the 110μm group the average flap thickness was 113.35±5.71μm. The difference between right and left eyes was not statistically significant(t100μm =-0.901, t 110μm=-0.490; P>0.05). Corneal flap thickness was not related to flap diameter(r=0.003, 0.018; P>0.05), preoperative patient age(r=0.022, 0.050; P>0.05), corneal thickness(r=0.051, 0.101; P>0.05), keratometric value K(r=-0.048, -0.136; P>0.05)or intraocular pressure(r=-0.113, 0.047; P>0.05). Preoperative corneal keratometric value K was positively correlated with corneal flap diameter(r=0.359, 0.532; P=0.01, 0.007CONCLUSION:The LASIK flap creation with the VisuMax femtosecond laser has relatively good predictability. There is no influencing factor for flap thickness.

AIM: To evaluate the safety, efficacy and stability of posterior chamber phakic intraocular lens(ICL)implanation and clear lens extraction for the correction of high myopia. METHODS: The study enrolled 56 cases(100 eyes)of high myopia. Group I comprised 32 cases(58 eyes)receiving ICL implantation and Group II comprised 24 cases(42 eyes)undergoing clear lens extraction. In this study, we evaluated the two groups of subject's the visual and refractive results, intraocular pressure(IOP), endothelial cell density(ECD), anterior chamber depth(ACD), lens transparency, the surgical complications as well as visual adverse symptoms before and after surgery.RESULTS: The postoperative subjects in group I and group II were followed, uncorrected vision acuity(UCVA)>0.5 were 69.0% in group I and 71.4% in group II after 3mo. UCVA>0.5 were 72.4% in group I and 73.8% in group II after 1a. Predictability of the manifest spherical equivalent refraction within ±1.00D was achieved in 62.1% of eyes in group I and 57.1% in group II after 1a. The central vault of the ICL(distance from posterior surface of ICL to the crystalline lens)measured with anterior segment optical coherence tomography(AS-OCT)was 0.35-0.54(0.40±0.16)mm. Twelve point one percent of eyes in group I and 7.1% of eyes in group II had transient mild increase in IOP. Here were statistically significant differences between preoperative and postoperative ECD(PCONCLUSION: ICL implantation and clear lens extraction are effective, safe and predictable surgical option for the management of high myopia. No severe complications occurred, but its long time effect and safety still need more time to prove.

Plant leaf litter is an important source of soil chemicals that are essential for the ecosystem and changes in leaf litter chemical traits during decomposition will determine the availability of multiple chemical elements recycling in the ecosystem. However, it is unclear whether the changes in litter chemical traits during decomposition and their similarities across species can be predicted, respectively, using other leaf traits or using the phylogenetic relatedness of the litter species. Here we examined the fragmentation levels, mass losses, and the changes of 10 litter chemical traits during 1-yr decomposition under different environmental conditions (within/above surrounding litter layer) for 48 temperate tree species and related them to an important leaf functional trait, i.e. leaf toughness. Leaf toughness could predict the changes well in terms of amounts, but poorly in terms of concentrations. Changes of 7 out of 10 litter chemical traits during decomposition showed a significant phylogenetic signal notably when litter was exposed above surrounding litter. These phylogenetic signals in element dynamics were stronger than those of initial elementary composition. Overall, relatively hard-to-measure ecosystem processes like element dynamics during decomposition could be partly predicted simply from phylogenies and leaf toughness measures. We suggest that the strong phylogenetic signals in chemical ecosystem functioning of species may reflect the concerted control by multiple moderately conserved traits, notably if interacting biota suffer microclimatic stress and spatial isolation from ambient litter.

Aim: Coastal wetlands provide crucial ecosystem functions and services, such as coastal protection, nutrient retention and C sequestration. Despite the important roles in global C, N and P cycling, the global variation in leaf stoichiometry across coastal wetlands remains unclear. Location: Global. Time period: 1980-2018. Major taxa studied: Vascular plants. Methods: By compiling a global dataset of 698 data records in 205 sites, we carried out systematic analyses of the world-wide trends and their determinants of leaf element contents and ratios of plants across coastal wetlands. Results: Leaf N and P contents increased significantly, but C:N, C:P and N:P ratios decreased with increasing latitude in coastal wetlands. The mean annual temperature was the predominant driver of leaf N, P and C:N, whereas soil N:P was a good predictor of leaf C:P and N:P ratios. Furthermore, N increased faster with P in plant leaves of coastal wetlands compared with terrestrial ecosystems. Within coastal wetlands, herb-dominated salt marshes had a significantly higher leaf P content, lower leaf N:P ratio and lower scaling exponent of leaf N to P than tree-dominated mangroves. Main conclusions: The similar latitudinal patterns of leaf stoichiometry in coastal wetlands compared with terrestrial ecosystems reflected the similar influences of temperature. However, different slopes of leaf P and N:P ratios and N and P scaling relationships between these two ecosystems suggested that different salinity and tidal inundation levels result in different strategies of N and P use in coastal wetland plants. These differences in leaf stoichiometry between ecosystems and between different types of coastal wetlands might need to be emphasized in future biogeochemical modelling owing to their different roles in global nutrient and carbon cycling. [ABSTRACT FROM AUTHOR]

According to the 171 Å observation of Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) in 2013 December 25∼26, a series of homologous jets were continuously found in the southwestern area of the active region NOAA 11931, from which 12 typical jets were selected and studied in this paper. The magnetic field structures in most jets had an obviously untwisting motion in the ejection process, though a few of them didn’t have. The process of some jets was divided into two phases: the slow ejection without untwisting, and the rapid untwisting ejection. Before some jets started, a bright point grew along the bottom of magnetic arcade, and extended from the end remote from the jet to the end proximate to the jet, and there were two parts of magnetic structures near the bottom of magnetic arcade untwisted simultaneously in the ejection process. During the final one jet, two magnetic arcades appeared successively in the southeastern end of the magnetic structure on the jet bottom, while a small magnetic loop emerged in the northwestern end. Compared with the line-of-sight magnetogram of SDO/Helioseismic and Magnetic Imager (SDO/HMI), in about 4 h before the first jet appeared, a pair of magnetic dipoles emerged from the bottom of magnetic structure, and continuously lifted during the whole jet event. Although overall the bottom magnetic field emerged before and after the 12 jets, but for each individual jet, the variation of the bottom magnetic field was different from one another: in some jets, the magnetic field near the magnetic arcade on the jet bottom exhibited both magnetic emergence and cancellation; but in other jets, the magnetic field near the jet bottom exhibited only an obvious emergence or cancellation. [ABSTRACT FROM AUTHOR]

Resource allocation to different functions is central in life-history theory. Plasticity of functional traits allows clonal plants to regulate their resource allocation to meet changing environments. In this study, biomass allocation traits of clonal plants were categorized into absolute biomass for vegetative growth vs. for reproduction, and their relative ratios based on a data set including 115 species and derived from 139 published literatures. We examined general pattern of biomass allocation of clonal plants in response to availabilities of resource (e.g., light, nutrients, and water) using phylogenetic meta-analysis. We also tested whether the pattern differed among clonal organ types (stolon vs. rhizome). Overall, we found that stoloniferous plants were more sensitive to light intensity than rhizomatous plants, preferentially allocating biomass to vegetative growth, aboveground part and clonal reproduction under shaded conditions. Under nutrient- and water-poor condition, rhizomatous plants were constrained more by ontogeny than by resource availability, preferentially allocating biomass to belowground part. Biomass allocation between belowground and aboveground part of clonal plants generally supported the optimal allocation theory. No general pattern of trade-off was found between growth and reproduction, and neither between sexual and clonal reproduction. Using phylogenetic meta-analysis can avoid possible confounding effects of phylogeny on the results. Our results shown the optimal allocation theory explained a general trend, which the clonal plants are able to plastically regulate their biomass allocation, to cope with changing resource availability, at least in stoloniferous and rhizomatous plants. [ABSTRACT FROM AUTHOR]

Leaf economics spectrum (LES), characterizing covariation among a suite of leaf traits relevant to carbon and nutrient economics, has been examined largely among species but hardly within species. In addition, very little attempt has been made to examine whether the existence of LES depends on spatial scales. To address these questions, we quantified the variation and covariation of four leaf economic traits (specific leaf area, leaf dry matter content, leaf nitrogen and phosphorus contents) in a cosmopolitan wetland species (Phragmites australis) at three spatial (inter-regional, regional, and site) scales across most of the species range in China. The species expressed large intraspecific variation in the leaf economic traits at all of the three spatial scales. It also showed strong covariation among the four leaf economic traits across the species range. The coordination among leaf economic traits resulted in LES at all three scales and the environmental variables determining variation in leaf economic traits were different among the spatial scales. Our results provide novel evidence for within-species LES at multiple spatial scales, indicating that resource trade-off could also constrain intraspecific trait variation mainly driven by climatic and/or edaphic differences. [ABSTRACT FROM AUTHOR]

The rapid increase of pasture containing lucerne (Medicago sativa) has increased demands for the continual supply of high quality seed, especially in China. Irrigation times are important for seed production. Five irrigation treatments, including (1) irrigation at podding and flowering and regrowth (when the shoots start emerging from the crown); (2) irrigation at podding and regrowth stages; (3) irrigation at flowering and regrowth; (4) irrigation at branching and regrowth; (5) irrigation at the regrowth stage only, were used to determine the effect of irrigation times on seed yield, its components, and seed distribution within plant in this field experiment. Treatment 5 is the local farmer irrigation practice, and was used as the control treatment. There were significant differences in seed yields between treatments, but not between two successive seasons. Irrigation at regrowth and podding produced the greatest seed yield, followed by, in decreasing order: regrowth stage; flowering and regrowth stage; podding and flowering and regrowth stage; branching and regrowth stage. Compared with irrigation at the regrowth stage only, irrigation at podding and regrowth stages significantly increased the fertile shoots per plant, racemes per plant and pods per raceme, which contributed to higher seed yield. Irrigation at flowering or branching greatly increased the shoots per plant, but reduced the fertile shoots per plant, and further decreased the seed yield. Seed weight per 100 pods in the treatment irrigated in the podding and regrowth stages was significantly greater than that in the other irrigation treatments. This study also showed that irrigation influenced the seed distribution in the plant, with more frequent irrigations producing seeds on the tops of plants. [ABSTRACT FROM AUTHOR]