Strong evidence for latitudinal diversity gradient in mosses across the world

Species richness generally decreases with increasing latitude,a biodiversity gradient that has long been considered as one of the few laws in ecology.This latitudinal diversity gradient has been observed in many major groups of organisms.In plants,the latitudinal diversity gradient has been observed in vascular plants,angiosperms,ferns,and liverworts.However,a conspicuous latitudinal diversity gradient in mosses at a global or continental scale has not been observed until now.Here,we analyze a comprehensive data set including moss species in each band of 20° in latitude worldwide.Our results show that moss species richness decreases strongly with increasing latitude,regardless of whether the globe is considered as a whole or different longitudinal segments(e.g.,Old World versus New World) are considered separately.This result holds when variation in area size among latitudinal bands is taken into account.Pearson's correlation coefficient between latitude and species richness is-0.99 for both the Northern and Southern Hemispheres.Because bryophytes are an extant lineage of early land plants and because mosses not only include most of extant species of bryophytes but also are important constituents of most terrestrial ecosystems,understanding geographic patterns of mosses is particularly important The finding of our study fills a critical knowledge gap.

Establishment of In Vitro Regeneration System of the Atrichum Mosses

In vitro regeneration systems of Atrichum mosses, Atrichurn undulatum (Hedw.) P. Beauv. and A. undulatum var. minus (Hedw.) Par. were established. After one month, soft, friable and green calli were induced successfully from inoculated protonema of Atrichum mosses on MS medium containing glucose (4%) and 6-BA (0.2-2.0 mg/L). The suitable culture medium for the callus induction and regular subculture was MS medium with 1.0-2.0 mg/L 6-BA and 4% glucose. The calli of Atrichum mosses developed into protonema, when it was transferred to phytohormone-free MS medium with 4% glucose. Meanwhile, the calli developed into erect gametophytes through protonema phase on carbohydrate-free Benecke medium.

Early Miocene Mosses from Weichang, North China, and their Environmental Significance

Twenty-seven moss specimens collected from the Guangfayong section （Early Miocene,22.1 Ma） of the Weichang District,North China were investigated in the present study.Based on the morphological and anatomical features of gametophytes,all specimens were found to belong to three species：Leptodictyum riparium,Drepanocladus subtrichophyllus sp.nov.,and Amblystegium varium,all of which belong to the family Amblystegiaceae.The microhabitats and living environments of fossil mosses were also investigated based on comparison with living mosses.The results suggest that these mosses grew primarily at the edges of rivers,streams,and lakes and favored being submerged in streams or lakes in the Weichang District in the Early Miocene.

Early Snowmelt Enhances the Carbon Sequestration of Hummock-Forming Sphagnum Mosses on Boreal Wetlands

Sphagnum mosses are globally important owing to their considerable peat-forming ability and their potential impact on global climatic cycles acting as a long-term net carbon sink. However, changes in climatic conditions due to global warming may affect the relations between Sphagnum mosses and vascular plants but also the competition among Sphagnum, and thus alter the accumulation of carbon on boreal wetlands. Sphagnum mosses are a plant genus with a favorable ability to grow in low solar irradiance and temperature conditions compared to vascular plants. This may be increasingly beneficial in increased wintertime temperatures and predated snowmelt conditions. To understand particularly the importance of early spring photosynthetic activity and thus the role of the length of growing season on carbon balance, we analyzed the CO2 exchange of Sphagnum mosses with closed chamber technique in two categories of microtopographical habitats, hummocks and lawns, during four seasons 2010-2013 on a raised bog in Central Finland. During CO2 exchange measurements, instantaneous net ecosystem exchange (NEE) and ecosystem respiration (RE) were measured. Our results show that the mean measured seasonal NEE, i.e. the instantaneous net carbon sequestration, of hummocks was generally only slightly higher than the NEE of lawns, but the mean measured seasonal RE of hummocks was clearly and significantly higher than the RE of lawns in every study year. A reason for the observed still higher seasonal carbon sequestration of hummocks than that of lawns besides the slightly higher rate of carbon accumulation was the longer duration of physiologically active growing season. Therefore, hummock-forming Sphagnum mosses exposed firstly from snow cover showed to get the extra time for photosynthesis and thus extra benefit compared to other mire plants. This may be further enhanced by the expansion of hummock-forming Sphagnum moss dominated raised bogs towards northern aapa-mire region due to the global warming.

Discrepancies in Growth Measurement Methods of Mosses: An Example from Two Keystone Species Grown under Increased CO₂and N Supply in a Restored Peatland

Bryophytes dominate northern peatlands. Obtaining reliable measurements of moss-growth and how it may be affected by global changes are therefore important. Several methods have been used to measure moss-growth but it is unclear how comparable they are in different conditions and this uncertainty undermines comparisons among studies. In a field experiment we measured the growth and production of Sphagnum fallax (Sphagnum) and Polytrichum strictum (Polytrichum) using two handling methods, using cut and uncut plants, and three growth-variables, height-growth, length-growth, and mass-growth. We aimed “benchmarking” a combination of six methodological options against exactly the same set of factorial experiments: atmospheric CO2 enrichment and N addition. The two handling methods produced partly different results: in half of the cases, one method revealed a significant treatment effect but the other one did not: significant negative effects on growth were only observed on uncut plants for elevated CO2 and on cut plants for N addition. Furthermore, the correspondence between measurements made with various growth-variables depended on the species and, to a lesser extent, treatments. Sphagnum and Polytrichum growth was inhibited under elevated CO2, and correlated to higher ammonium values. Sphagnum was however less affected than Polytrichum and the height difference between the two species decreased. N addition reduced the P/N ratio and probably induced P-limiting conditions. Sphagnum growth was more inhibited than Polytrichum and the height difference between the two species increased. Our data show that such a problem indeed exists between the cut and uncut handling methods. Not only do the results differ in absolute terms by as much as 82% but also do their comparisons and interpretations depend on the handling method—and thus the interpretation would be biased—in half of the cases. These results call for caution when comparing factorial studies based on different handling methods.

Comparison of Mosses as Bioindicator of Heavy Metal Pollution in Aramoko-Ekiti and Are-Ekiti, Nigeria

The increasing global concern over the public health impacts attributed to environmental pollution led us to investigate and compare the deposition of some heavy metals in mosses from an urban area, Aramoko Ekiti and a rural area, Are Ekiti. Both towns are located in the SouthWest, Nigeria. Moss samples were collected at different sites in the two towns. These samples were then digested in acid and analysed for Cd, Cr, Ni, Pb and Cu, using a flame atomic absorption spectrometer. The results of the study show variations in the concentrations of the heavy metals among the different sites in each town as well as between the two towns. Apart from cd which was suspected to have originated from natural sources in the investigated samples, the relatively higher concentrations of the other metals in Aramoko-Ekiti suggests an important anthropogenic source which we suspect to be automobiles since there are little or no industrial or mining activities within the town. Furthermore, the relatively higher concentrations of the metals exhibited by moss samples collected around locations prone to higher traffic situations in the two towns such as roadsides, filling stations and garages stresses the significance of traffic density in heavy metal pollution of the environment. These places （filling stations and garages） should be sited far away from residential areas. Also, residences should be sited at considerably far distances from major roads. These will prevent the bioaccumulation of the heavy metals in residents. Though, the results show that Aramoko-Ekiti is more polluted with the heavy metals than Are-Ekiti, the concentration of the heavy metals were still within the permissible limits. Given the results of this work and similar ones, there is need to evaluate the pollution status of the environment from time to time especially the urban areas and high traffic areas.

Progress in the study of algae and mosses in biological soil crusts

Algae and mosses are not only two of the familiar communities in the process of desert vegetational succession,but also have the highest biomass in biological soil crusts.Meanwhile,being the pioneer plants,algae and mosses are involved in the establishment of biological soil crusts,which have great importance in arid environments and play a major role in desert ecosystems,such as being the indicator of the vegetation type,soil-holding,preventing erosion by water and wind,and sand fixation.This paper reviews the advances in the study of algae and mosses in arid and semi-arid areas.It mainly describes the ecological functions of algae and mosses including their influences on water cycle,circulation of substances,and community succession.In addition,the relationships between algae and mosses are discussed.Finally,some suggestions are proposed for the research orientations of algae and mosses in biological soil crusts.Ecologically,algae and mosses have significant ecological importance in arid areas,especially in those areas where environmental problems are becoming increasingly serious.

Nitrogen and phosphorus translocation of forest floor mosses as affected by a pulse of these nutrients

Aims Mosses are dominant in many ecosystems where nutrients from deposition are one of the main nutrient sources.However,it is difficult to evaluate mosses’role in nutrient cycling without knowledge of how mosses use deposited nutrient inputs.To fill this gap,the present study aims to investigate:(i)how nitrogen(N)and phosphorus(P)concentrations of new-grown segments change along a gradient of N or P amount in a pulse treatment?(ii)how do a pulse of major nutrient(N or P)affect N or P translocation rate along a moss shoot?and(iii)to what extent do N or P translocation rates link to nutrient status of the new-grown segments of mosses?Methods We measured N and P concentrations of segments with different ages in two dominant forest floor mosses,Actinothuidium hookeri and Hylocomium splendens,on 8 days and 1 year after N and P pulse treatment with an in situ experiment in a subalpine fir forest in eastern Tibetan Plateau.Important Findings Both mosses were efficient in taking up nutrients from a pulse of either N or P.Nitrogen and P concentrations of new-grown segments were affected by nutrient pulse treatments.These N and P concentration changes were attributed to the initial N and P concentration of the young segments harvested 8 days after nutrient pulse treatments,suggesting that the captured nutrients were reallocated to the new-grown segments via translocation,which was largely controlled by a source-sink relationship.While no significant relationship was found between N translocation rate and N:P ratio of the new-grown segments,P translocation rate explained 21%-23%of the variance of N:P ratio of the new-grown segments,implying importance of P transport in supporting the new-grown sections.These results suggest that nutrient(N,P)translocation is a key process for mosses to utilize intermittent nutrient supply,and thus make mosses an important nutrient pool of the ecosystem.

Comparisons of photosynthesis-related traits among understory lichens,mosses and vascular plant leaves in a high-elevation subalpine forest

Many mosses and lichens thrive in high-elevation subalpine forests and even become dominant species on the forest foor.Although they play an irreplaceable ecological role in the forest,less is known about their ecophysiological status,and how their photosynthesis-related functional traits differ from those of co-occurring vascular plants.We determined the carbon,nitrogen and phosphorus concentrations and stoichiometric ratios,tissue mass per area,chlorophyll concentrations and photosynthetic light–response curves of three lichens,three mosses and four vascular plants in a subalpine forest in the eastern Tibetan Plateau of China.Trait values were compared among and within each group.The lichens possessed a higher nitrogen concentration than that of mosses.In addition,the two poikilohydric groups exhibited lower concentrations of nitrogen,phosphorus and chlorophyll,light-saturated assimilation rates and photosynthetic nutrient use effciencies,and higher light compensation points than those of vascular plant leaves.Furthermore,variations in photosynthesis-related traits for lichen species refect their different adaptation strategies to their corresponding environments.In contrast,the differences were weak among the three forest-foor mosses and the three herb species.These results demonstrate that the high abundance of understory lichens and mosses in the high-elevation subalpine forest cannot be explained by the photosynthesis-related traits.

基于机器视觉的目标跟踪算法研究

针对遮挡情况下目标跟踪产生漂移的问题,提出一种基于MOSSE和Kalman滤波的目标跟踪算法以改善跟踪效果。算法使用MOSSE滤波器与目标图像的相关性度量来判断遮挡情况。无遮挡时,以MOSSE滤波器为主跟踪器,获取目标位置,更新MOSSE滤波器,并修正Kalman滤波器;遇到遮挡时,将Kalman滤波器设置为主跟踪器,预测目标位置,并保持MOSSE滤波器不变。实验从跟踪速度、精度、成功率等角度进行定性与定量分析,结果表明算法在遮挡情况下,实现目标的快速有效的跟踪。与同类算法比较,能有效改善遮挡情况下的跟踪效果,具有很强的鲁棒性。

Spatial Variation and Sources of Atmospheric Sulfur Deposition in Nanchang

[Objective] The paper aimed to discuss the relationship between sulfur contents of mosses and the concentration of SO2-4 and the source of Atmospheric sulfur in Nanchang.[Method] 29 moss samples （Bryohaplocladium micriophyllum （Hedw.） R.Watanabe et Iwats） were collected from four sampling points,including North campus and Qianhu campus of Nanchang Power Station were determined.[Result] The results showed that sulfur contents of mosses tissues in North campus of Nanchang University （0.45±0.059%） were higher than Qianhu campus of Nanchang University （0.26±0.002%）,which coincided with the changing law of the concentration of SO2-4.Sulphur isotope of mosses tissues was-0.64‰-9.71‰.Sulphur isotope of mosses tissues in Meling （4.02‰-9.71‰） was higher than Qianhu campus of Nanchang University （0.55‰-0.56‰） and power plant （-0.64‰-0.45‰）.[Conclusion] Relationship between sulphur contents and sulphur isotopes of mosses tissues showed sulfur source of sulphur deposition in Nanchang city was mainly affected by 34S-enriched sulphur transported from northerly air masses and biogenic sulfur.

Distribution Patterns of Ground Moss Species and Its Relationships with Environmental Factors in Changbai Mountain, Northeast China

The relationships of 42 species of ground moss with six environmental factors in 41 sites on Changbai Mountain Biosphere Reserve were analyzed. Four site groups and four groups of ground moss ecological species were identified using the method of Two-way Indicator Species Analysis (TWINSPAN). The results of Detrended Canonical. Correspondence Analysis (DCCA) showed that altitude, soil sand content, soil acidity, forest canopy coverage and soil water content are the five major environmental factors influencing the distributional patterns of the moss species. The four groups of ecological species, which correspond well with the four site groups, are projected on the species-environment biplot of DCCA. Group 1 dominated in the bogs of Larix olgensis forest, group 2 in the alpine tundra, group 3 in the dense conifer forest, and group 4 mainly in the Betula ermanii community and the Betula ermanii-Larix olgensis forest in sub-alpine respectively.

Recent developments in synthesis,properties,and applications of 2D Janus MoSSe and MoS_(x)Se_((1-x))alloys

The Janus MoSSe and alloy MoS_(x)Se_((1-x)),belonging to the family of two-dimensional(2D)transition metal dichalcogenides(TMDs),have gained significant attention for their potential applications in nanotechnology.The unique asymmetric structure of Janus MoSSe provides intriguing possibilities for tailored applications.The alloy MoS_(x)Se_((1-x))offers a tunable composition,allowing for the fine-tuning of the properties to meet specific requirements.These materials exhibit remarkable mechanical,electrical,and optical properties,including a tunable band gap,high absorption coefficient,and photoconductivity.The vibrational and magnetic properties also make it a promising candidate for nanoscale sensing and magnetic storage applications.Properties of these materials can be precisely controlled through different approaches such as size-dependent properties,phase engineering,doping,alloying,defect and vacancy engineering,intercalation,morphology,and heterojunction or hybridisation.Various synthesis methods for 2D Janus MoSSe and alloy MoS_(x)Se_((1-x))are discussed,including hydro/solvothermal,chemical vapour transport,chemical vapour deposition,physical vapour depositio,and other approaches.The review also presents the latest advancements in Janus and alloy MoSSe-based applications,such as chemical and gas sensors,surface-enhanced Raman spectroscopy,field emission,and energy storage.Moreover,the review highlights the challenges and future directions in the research of these materials,including the need for improved synthesis methods,understanding of their stability,and exploration of new applications.Despite the early stages of research,both the MoSSe-based materials have shown significant potential in various fields,and this review provides valuable insights for researchers and engineers interested in exploring its potential.

Moss Miami内固定及椎管减压治疗胸腰椎骨折的探讨

目的:探讨Moss Miami内固定及椎管减压治疗胸腰椎骨折的临床疗效.方法对18例胸腰椎骨折患者应用Moss Miami内固定系统进行复位内固定.结果:18例患者术中均获得良好复位,平均随访14个月(9～20个月),骨折全部愈合,无断钉、断棒、内固定松动等情况.结论:Moss Miami内固定操作简便,复位满意,固定牢靠,是治疗胸腰椎骨折有效治疗方法之一.

新一代温室气体排放情景

温室气体排放情景,是对未来气候变化预估的基础。过去应用的情景设计是在2000年完成的,早就需要更新与补充了,IPCC第4次评估报告已经提出了这个要求[1]。对于这种必要性Moss等[2]在2010年就进行了深入的讨论。通过2～3年的工作,新一代排放情景已经形成。

土法炼锌地区大气中镉的迁移

利用苔藓口袋(Moss bag)和总悬浮颗粒物(TSP)同步监测相结合,研究在上世纪80—90年代土法炼锌地区排放到大气中镉的迁移影响.结果发现,土法炼锌区域100 m内大气TSP中镉含量达129.4 mg·kg-1,土壤中镉含量为12.64 mg·kg-1,Moss bag监测镉总沉降速率达到47.20 mg·m-2·mon-1;在污染源下风方向10 km处TSP中镉含量仍达到27.3 mg·kg-1,土壤中镉含量为2.75 mg·kg-1,Moss bag监测镉总沉降速率达到5.18 mg·m-2·mon-1;随着与污染源距离增加,大气TSP和Moss bag镉沉降速率、土壤中镉含量均呈现逐渐降低的一致性趋势;Moss bag监测镉干沉降速率占总沉降速率的比例变化范围为58%—79%,说明从大气向地面沉降的镉总量中以干沉降为主,是重力影响的由大气向地面沉降的过程.

改进的基于特征融合MOSSE冠脉目标追踪算法

CT血管造影(computed tomography angiography,CTA)作为一种无创、检测精确较高的辅助诊断方法,尚急需能有效消除冠脉目标附近干扰噪声并寻求可全自动快速准确追踪目标的新算法以大幅减轻医生阅片压力、辅助其进行可靠诊断与治疗。提出了一种特征融合的误差最小平方和(minimum output sum of squared error,MOSSE)冠脉目标追踪新算法,通过提取冠脉血管多个特征,将其融合加入现有的MOSSE追踪方法,实现全自动准确快速追踪冠脉目标。使用河北大学附属医院9位患者(5男4女,均龄65岁,其中6位有冠心病史)的CTA数据进行了算法验证,并与文献已报道基于中心线提取和基于区域生长的现有冠脉目标提取算法进行了处理结果对比分析。结果表明,新算法处理追踪一例患者切片数据仅需耗时0.02 s,多个病例的平均准确度达94.30%,性能优于上述现有冠脉目标提取算法,能实现全自动准确高效追踪到形态变化剧烈的冠脉目标,可为冠心病的临床诊治起到更为高效的辅助作用。

后路椎板切除减压+横突间植骨融合+椎弓根钉内固定治疗老年退行性腰椎滑脱症疗效分析

目的探讨后路椎板切除减压+横突间植骨融合+椎弓根钉内固定治疗老年退行性腰椎滑脱症的临床效果.方法回顾性分析18例老年退行性腰椎滑脱症患者,均行后路椎板切除减压+横突间植骨融合+椎弓根钉内固定手术治疗,其中Moss-Miami固定4例,USS固定3例,GSS固定8例,RF固定3例.结果经6～24个月的随访,按Steffee分级:优10例(56%),良6例(33%),可2例(11%).结论后路椎板切除减压+横突间植骨融合+椎弓根钉内固定是治疗老年退行性腰椎滑脱症的有效方法.

Moss Miami内固定系统后路治疗胸腰椎骨折

目的探讨Moss Miami系统后路治疗胸腰椎骨折的经验。方法对收治的15例胸腰椎骨折病人应用Moss Miami钉棒系统后路进行复位固定。结果15例患者术中均获得良好复位,术中术后无死亡及神经损伤。平均随访11.5个月,矫正角丢失<5°;9例不全瘫病人,术后神经功能完全恢复3例,部分改善6例。结论Moss Miami内固定系统具有良好的复位和固定作用,术后维持复位效果良好,是治疗胸腰椎骨折有效治疗方法之一。