Prediction of Suitable Habitat for Lycophytes and Ferns in Northeast China: A Case Study on Athyrium brevifrons

Suitable habitat is vital for the survival and restoration of a species.Understanding the suitable habitat range for lycophytes and ferns is prerequisite for effective species resource conservation and recovery efforts.In this study, we took Athyrium brevifrons as an example, predicted its suitable habitat using a Maxent model with 67 occurrence data and nine environmental variables in Northeast China.The area under the curve(AUC) value of independent test data, as well as the comparison with specimen county areal distribution of A.brevifrons exhibited excellent predictive performance.The type of environmental variables showed that precipitation contributed the most to the distribution prediction, followed by temperature and topography.Percentage contribution and permutation importance both indicated that precipitation of driest quarter(Bio17) was the key factor in determining the natural distribution of A.brevifrons, the reason could be proved by the fern gametophyte biology.The analysis of high habitat suitability areas also showed the habitat preference of A.brevifrons: comparatively more precipitation and less fluctuation in the driest quarter.Changbai Mountains, covering almost all the high and medium habitat suitability areas, provide the best ecological conditions for the survival of A.brevifrons, and should be considered as priority areas for protection and restoration of the wild resource.The potential habitat suitability distribution map could provide a reference for the sustainable development and utilisation of A.brevifrons resource, and Maxent modelling could be valuable for conservation management planning for lycophytes and ferns in Northeast China.

Genome size evolution of the extant lycophytes and ferns

Ferns and lycophytes have remarkably large genomes.However,little is known about how their genome size evolved in fern lineages.To explore the origins and evolution of chromosome numbers and genome size in ferns,we used flow cytometry to measure the genomes of 240 species(255 samples)of extant ferns and lycophytes comprising 27 families and 72 genera,of which 228 species(242 samples)represent new reports.We analyzed correlations among genome size,spore size,chromosomal features,phylogeny,and habitat type preference within a phylogenetic framework.We also applied ANOVA and multinomial logistic regression analysis to preference of habitat type and genome size.Using the phylogeny,we conducted ancestral character reconstruction for habitat types and tested whether genome size changes simultaneously with shifts in habitat preference.We found that 2 C values had weak phylogenetic signal,whereas the base number of chromosomes(x)had a strong phylogenetic signal.Furthermore,our analyses revealed a positive correlation between genome size and chromosome traits,indicating that the base number of chromosomes(x),chromosome size,and polyploidization may be primary contributors to genome expansion in ferns and lycophytes.Genome sizes in different habitat types varied significantly and were significantly correlated with habitat types;specifically,multinomial logistic regression indicated that species with larger 2 C values were more likely to be epiphytes.Terrestrial habitat is inferred to be ancestral for both extant ferns and lycophytes,whereas transitions to other habitat types occurred as the major clades emerged.Shifts in habitat types appear be followed by periods of genomic stability.Based on these results,we inferred that habitat type changes and multiple whole-genome duplications have contributed to the formation of large genomes of ferns and their allies during their evolutionary history.

Chemical constituents and biological activities of lycophytes and ferns

Lycophytes and ferns are unique and charismatic members of many terrestrial ecosystems and occupy the pivotal position in land plant origin and evolution.The Chinese lycophytes and ferns flora,with approximately 2000 species,contributes a substantial component to the global lycophytes and ferns diversity,with estimates of 12000 species.Among them,about 433 species are medicinally recorded and researches based on their phytochemical properties are important topics in natural medicines.This paper reviewed the research history and current status of chemical constituents and biological activities of lycophytes and ferns,which had highlighted the research progress of our group.

贵州省野生观赏蕨类植物资源及其开发利用

1自然概况贵州省位于中国西南地区的云贵高原东部,地处103°36′～109°35′E、24°37′～29°13′N,东接湖南,南邻广西,西毗云南,北连四川和重庆。总面积17.6万km2。贵州地貌属中国西部高原山地,境内地势西高东低,自中部向北、东、南3面倾斜,岩溶地貌发育非常典型,平均海拔约1100m。贵州省气候属亚热带湿润季风气候。

基于多分类的虹膜匹配方法

在传统的虹膜识别系统中,虹膜匹配被认为是一个二分类问题:类内匹配和类间匹配。许多已存在的方法简单地利用距离来执行虹膜匹配。由于这些方法不能很好地利用虹膜特征,所以会产生很高的拒识率和误识率,且鲁棒性不强。为了解决这些问题,提出把虹膜匹配当作一个多分类问题,采用一种新颖的蕨算法(Ferns)分类器来完成该工作。相比支持向量机(SVM)分类器,在执行虹膜匹配时,Ferns分类器有诸多优点。为了对提出的算法给出全面评价,实验中分别在认证和识别这2种模式下对该算法进行测试。实验结果证明,提出的方法可以极大地改善虹膜识别系统的性能。

融合多重Bayesian决策的多视角视频车辆快速检索算法

从图像特征点匹配的角度出发,提出一种融合多重Bayesian决策的多视角视频车辆快速检索算法.算法基于随机Ferns特征,对目标车辆的多视角图片进行特征点提取,融合多视角图片特征点进行特征训练,构建双层贝叶斯分类器,融合两重Bayesian决策计算视频图像中检测出的特征点集的联合概率,为当前视频图像分配类标签,完成多视角视频车辆的快速检索.对比试验表明,该算法与其他利用图像匹配算法进行视频检索的方法相比具有较高的识别率和较低的时间复杂度,并具备一定的实际使用价值.

Extending harmonized national forest inventory herb layer vegetation cover observations to derive comprehensive biomass estimates

Background:National forest inventories(NFI)have a long history providing data to obtain nationally representative and accurate estimates of growing stock.Today,in most NFIs additional data are collected to provide information on a range of forest ecosystem functions such as biodiversity,habitat,nutrient and carbon dynamics.An important driver of nutrient and C cycling is decomposing biomass produced by forest vegetation.Several studies have demonstrated that understory vegetation,particularly annual plant litter of the herb layer can contribute significantly to nutrient and C cycling in forests.A methodology to obtain comprehensive,consistent and nationally representative estimates of herb layer biomass on NFI plots could provide added value to NFIs by complementing the existing strong basis of biomass estimates of the tree and tall shrub layer.The study was based on data from the Swiss NFI since it covers a large environmental gradient,which extends its applicability to other NFIs.Results:Based on data from 405 measurements in nine forest strata,a parsimonious model formulation was identified to predict total and non-ligneous herb layer biomass.Besides herb layer cover,elevation was the main statistically significant explanatory variable for biomass.The regression models accurately predicted biomass based on absolute percentage cover(for total biomass:R2=0.65,p=0;for non-ligneous biomass:R2=0.76;p=0)as well as on cover classes(R2=0.83;p=0;and R2=0.79,p=0),which are typically used in NFIs.The good performance was supported by the verification with data from repeated samples.For the 2 nd,3 rd,and 4 th Swiss NFI estimates of non-ligneous above-ground herb layer biomass 586.6±7.7,575.2±7.6,and 586.7±7.9 kg·ha-1,respectively.Conclusions:The study presents a methodology to obtain herb layer biomass estimates based on a harmonized and standardized attribute available in many NFIs.The result of this study was a parsimonious model requiring only elevation data of sample plots in addition to NFI cover estimates to provide unbiased estimates at the national scale.These qualities are particularly important as they ensure accurate,consistent,and comparable results.

A survey of arsenic and other heavy metals in vegetation from markets or mine tailings

This research includes two investigations. The first one is a market basket survey of the levels of arsenic （As） and trace elements in bracken fern （Pteridium aquilinum） originated from three countries： South Korea, China and North Korea. The results showed that the mean As concentrations in stems of samples were significantly higher than those in leaves. As concentrations in all samples did not exceed food safety limits for vegetables. Generally, concentrations of Fe, Mn, Cu and Zn in leaves were higher than those in stems. The second investigation is a survey on the levels of As and other heavy metals in vegetation in the vicinity of Myoungbong mine tailings. The results demonstrated that As, Pb and Cu concentrations and bioaccumulation factors （BCF） in seedlings of the fern（A splenium achilleifolium） were the highest, whereas Marsh horsetail（Equisetum polustre） accumulated the highest levels of Zn. Concentrations of As, Pb, Zn and Cu in vegetable-cress （Lepidium sativum） and the edible herb-aromatic madder （Elasholtzia splendens） were higher than food safety limits. Therefore, a risk assessment of As and other heavy metals in vegetables and herbs on local human health should be conducted in the future.

Importance of Quercus spp.for diversity and biomass of vascular epiphytes in a managed pine-oak forest in Southern Mexico

Background:Forestry management modifies the diversity,structure,and functioning of intervened forests.Timber extraction reduces tree density and basal area,leading to changes in the communities of vascular epiphytes.The objective of this study was to evaluate the diversity and biomass of vascular epiphytes in Quercus trees remaining in two pine-oak forest stands that have been subjected to two stages of the Silvicultural Development Method(release cutting,and thinning)in comparison with an unharvested old-secondary forest in southern Mexico.For each treatment,richness of epiphytes present on 60 oak trees was recorded and their dry biomass estimated.We calculated the true diversity(Hill numbers)and beta diversity using the Jaccard coefficient of similarity,and generated rank abundance curves per taxonomic epiphyte group(bromeliads,orchids,ferns and others).For each treatment,the relationships between overall diversity and epiphyte biomass to the host trees basal area were analyzed using log linear models.Results:We recorded a total of 67 species of epiphytes species belonging to 10 families hosted by five species of oaks.The greatest species richness(^(0)D)was recorded in the old-secondary forest.Fewer common(^(1)D)and dominant(^(2)D)species were recorded in the release cutting than in the other treatments.Epiphyte diversity and biomass were both slightly related to host tree basal area.Composition of epiphytes was similar(60%)among treatments,although orchids,bromeliads,and other families were more diverse in the old-secondary forest.Most bromeliad species were shared across all treatments,although orchids presented the most exclusive species in the unharvested forest.The bromeliad Tillandsia seleriana provided the greatest contribution to biomass in all treatments,followed by the orchid Camaridium densum.Generalized linear models indicated that epiphyte diversity was significantly related to treatment,and epiphyte biomass to basal area of host trees.Conclusions:Although forest management affects diversity,composition,and abundance of vascular epiphytes,most of their diversity and biomass can be maintained despite timber harvesting.This requires sparing some mature oaks during logging,as they contribute to conservation,establishment,and development of epiphytic communities,and maintaining untreated areas as a source of propagules for these communities.

Fern extracts potentiate fluconazole activity and inhibit morphological changes in Candida species

Objective: To investigate the antifungal activity of the fern species Lygodium venustum(L. venustum) and Pityrogramma calomelanos(P. calomelanos) against Candida albicans and Candida tropicalis strains.Methods: The microdilution method was used to evaluate the antifungal activity, as well as the modulating effects of ethanolic extracts of these plants in combination with fluconazole. The minimum inhibitory concentration(MIC), minimum fungicide concentration and morphological changes were also determined.Results: The extract obtained from L. venustum presented a MIC > 8 192 mg/m L, while the extract obtained from and P. calomelanos presented a MIC = 8 192 mg/m L, indicating that they present weak antifungal activity. However, combination of the extracts with Fluconazole potentiated the antifungal activity of this drug. At different experimental conditions, such as concentration of the extract and type of strain, the extracts inhibited hyphae and pseudohyphae formation, indicating that these fern species can affect the morphology of the fungi.Conclusions: The extracts obtained from the fern species L. venustum and P. calomelanos dose not present significant antifungal activity. However, P. calomelanos potentiates the activity of fluconazole and both extracts inhibits the morphological changes in Candida species, indicating that they have potential pharmacological activity as modulators of fungal biology. Therefore, novel studies are required to characterize the interference of these extracts in the virulence and pathogenicity of Candida species as well as the potential of fern species to treat fungal infections.

Novelties in <i>Campyloneurum</i>(Polypodiaceae) from Mesoamerica

Three new species are described and another is recognized in Campyloneurum. Two species occur in Mexico to El Salvador and the others two are present in Nicaragua, Costa Rica and Panama. The new species are Campyloneurum acutum A. Rojas, C. leoniae A. Rojas and C. madrense A. Rojas. The first species differs from C. xalapense by broader rhizome scales, acute to attenuate blade apex, commonly two series of areoles between parallel veins, commonly one sori per areole and hydathodes absent or few evident. Campyloneurum leoniae differs from C. irregulare by more compact and non-pruinose rhizomes, thinner stipes, relatively broader, thinner and more opaque laminae, and distribution at lower elevations. Campyloneurum madrense is different to C. angustifolium because it has narrower and darker rhizome scales with denticulate margin, long scales cells and distributed at lower elevations. Finally, Campylonerum pittieri is here recognized as valid species and it differs from the similar C. amphostenon by longer rhizomes with appressed scales that have a patent, long acuminate apices, relative broader laminae, veins evident and distribution at higher elevations.

Four New Species and Additional Distributions of <i>Elaphoglossum</i>Section <i>Elaphoglossum</i>(Dryopteridaceae) from the Neotropics

Four new species of Elaphoglossum sect. Elaphoglossum are described: E. Amparoanum A. Rojas, E. Chocoense A. Rojas, E. Fayorum A. Rojas and E. Luciae A. Rojas. The first species is related to E. Variolatum Mickel, but differs from it by having rhizome scales bicolorous and long ciliate margin. The second species is different to E. moranii Mickel by having narrower rhizome, shorter stipe, elliptic blade, attenuate blade base, shorter fertile fronds with blackish costa and present at lower altitudinal distribution. After that, the third species differs from E. lingua (C. Presl) Brack. by pale rhizome scales with long ciliate margin, shorter fronds and blade scales denser and lighter. Finally, the fourth species is related to E. atrosquamatum Mickel, but with relative longer fronds and broader blade. The geographical distributions of E. guatemalense (Klotzsch) T. Moore, E. longicrure Christ, E. minutum (Pohl ex Fée) T. Moore and E. nicaragüense A. Rojas are expanded.

Five New Species of <i>Diplazium</i>Sw. (Athyriaceae) from Nicaragua, Costa Rica and Colombia

Five new species are described in the genus Diplazium Sw. from Nicaragua, Costa Rica and Colombia, as results of studies in the Neotropical ferns. The new species are Diplazium chirripoense A. Rojas, Diplazium cornutum A. Rojas, Diplazium crassirhizoma A. Rojas, Diplazium lustrosum A. Rojas and Diplazium rodriguezii A. Rojas. The first species is related to D. skutchii Lellinger, but differs from it by having glabrous stipe, glabrous blade abaxially, hyaline and entire indusia, and distributed and higher elevations. The second species is different to D. diplazioides (Klotzsch et H. Karst.) Alston by having densely scaly stipe, rachis and costa, relative bigger pinnae and entire to erose indusia. After that, the third species differs from D. werckleanum Christ by thicker rhizome, bigger rhizome scales and blade with 1 - 2 buds at apex. Consecutively, the fourth species differs from D. lindbergii (Mett.) H. Christ by thinner rhizome, shorter fronds, longer stipe, smaller blade, less pinnae pairs, shiny laminar tissue and veins 3 - 5 pairs per segment. Finally, the fifth species is related to D. tungurahuae (Sodiro) C. Chr., but with abaxially glabrous rachis and costae, pinnules 4 - 5 times longer than wide and entire, costules adaxially without wings, veins abaxially glabrous and reticulate along costae and between pinnate veins.

Palynological Studies of Some Species of Aspleniaceae-Pteridophyta

Palynology of six fern species belonging to the family Aspleniaceae from Saudi Arabia are investigated by light microscope (LM). These are: Asplenium aethiopicum, Asplenium trichomanes, Asplenium adiantum-nigrum, Asplenium sp.1, Asplenium sp.2 and Ceterach officinarum. All studied spores are oblate-spheroidal in shape class, with 11 - 50 μm in equatorial diameter and with 12 - 49 μm in polar diameter. Two types of spores are recognized: monolete spores in Asplenium aethiopicum, Asplenium trichomanes, Asplenium adiantum-nigrum, Asplenium sp.2 and trilete spores in Asplenium sp.1 and Ceterach officinarum. The exospore (perine) is homogeneous and apparently double-layered in all the studied spores. The perispore is single or double-layered with a microlacunouse structure. The perispore layers can be distinguished by their different contrast, structure and thickness. The exospore sculpture varies from cristates-ridged (Asplenium aethiopicum), cristates granulate (Asplenium adiantum-nigrum), cristates scabrate (Asplenium trichomanes), regulate-scabrates (Asplenium sp.1 and Ceterach officinarum) to papillate or tuberculate sculpture (Asplenium sp.2). Comparison between the earlier studies of some species from Saudi Arabia is given. General characteristics like spore type, ornamentation and laesurae features as well as the number of exospore layers could be useful for taxonomy of Aspleniaceae.

Late Triassic flora of the northern part of the Fore-Caspian depression(Kazakhstan)as exemplified by data from the S.Nurzhanov-509 borehole

The Late Triassic Nurzhanov flora is characterized on the basis of the material originated from the S.Nurzhanov-509 borehole disposed in the northern part of the Fore-Caspian depression,near the City of Atyrau,Republic of Kazakhstan.Taxonomic composition of the Nurzhanov flora includes equisetophytes Neocalamites sp.,ferns Phlebopteris hazarensis Naugolnykh et Pronin,Todites sp.,Cladophlebis sp.,ginkgophytes Ginkgoites spp.,conifers Podozamites sp.Palaeophytogeographic status of the Nurzhanov flora is discussed.According to the data obtained,this flora belongs to a transitional zone(an ecotonous belt),which existed between the Euro-Sinian and the Siberian-Canadian palaeofloristic realms during most of the Mesozoic time.

Ce、Mn、Cr对高铁共晶铝硅活塞合金组织和性能的影响

采用正交试验方法，研究了Ce、Mn、Cr对高铁共晶铝硅合金组织和性能的影响。发现：Mn、Cr改善了β（Al9FeSi3）相的形貌，形成含Mn、Cr铁相；稀土Ce对共晶硅的细化作用明显，在高的Ce质量分数下，Ce进入含Mn、Cr的铁相，很好地改善其形貌、减小铁相的尺寸，并能代替Ni的位置形成耐高温Al-Ni-Cu-Ce相。Ce、Fe、Mn、Cr的最佳加入量为0．8％、1．0％、0．4％、0．1％，合金常温（25℃）和高温（300℃）抗拉强度分别达到270．3MPa、136．7MPa，完全能满足新型活塞高温负荷的使用要求。

Global patterns of fern species diversity:An evaluation of fern data in GBIF

Despite that several studies have shown that data derived from species lists generated from distribution occurrence records in the Global Biodiversity Information Facility(GBIF)are not appropriate for those ecological and biogeographic studies that require high sampling completeness,because species lists derived from GBIF are generally very incomplete,Suissa et al.(2021)generated fern species lists based on data with GBIF for 100 km×100 km grid cells across the world,and used the data to determine fern diversity hotspots and species richness-climate relationships.We conduct an evaluation on the completeness of fern species lists derived from GBIF at the grid-cell scale and at a larger spatial scale,and determine whether fern data derived from GBIF are appropriate for studies on the relations of species composition and richness with climatic variables.We show that species sampling completeness of GBIF is low(<40%)for most of the grid cells examined,and such low sampling completeness can substantially bias the investigation of geographic and ecological patterns of species diversity and the identification of diversity hotspots.We conclude that fern species lists derived from GBIF are generally very incomplete across a wide range of spatial scales,and are not appropriate for studies that require data derived from species lists in high completeness.We present a map showing global patterns of fern species diversity based on complete or nearly complete regional fern species lists.

Late Pliocene diversity and distribution of Drynaria(Polypodiaceae) in western Yunnan explained by forest vegetation and humid climates

The palaeodiversity of flowering plants in Yunnan has been extensively interpreted from both a molecular and fossil perspective. However, for cryptogamic plants such as ferns, the palaeodiversity remains poorly known. In this study, we describe a new ferny fossil taxon, Drynaria lanpingensis sp. nov. Huang,Su et Zhou(Polypodiaceae), from the late Pliocene of northwestern Yunnan based on fragmentary frond and pinna with in situ spores. The frond is pinnatifid and the pinnae are entirely margined. The sori are arranged in one row on each side of the primary vein. The spores have a semicircular to bean-shaped equatorial view and a tuberculate surface. Taken together with previously described fossils, there are now representatives of three known fossil taxa of Drynaria from the late Pliocene of western Yunnan.These finds suggest that Drynaria diversity was considerable in the region at that time. As Drynaria is a shade-tolerant plant, growing preferably in wet conditions in the understory of forests, its extensive existence may indicate forest vegetation and humid climates in western Yunnan during the late Pliocene.This is in line with results from floristic investigations and palaeoclimatic reconstructions based on fossil floras.

基于改进的TLD算法的手势跟踪算法

该文在分析表征手势特征基础上,分别根据金字塔LK原理、FERN分类原理和P-N学习原理及手运动轨迹的连续性规律来研究适用于手势识别的关键技术,即手势目标跟踪技术、P-N学习的样本增长和修剪技术的算法。针对目前在手的局部区域跟踪过程中,手势目标跟踪失败后难以恢复和容易受到脸部、肤色和手臂的干扰等问题,该文在TLD单目标跟踪算法的基础上,提出了一种改进的多目标手势局部区域跟踪TLD算法,针对算法的检测模块,在FERN分类器的基础上,采用颜色特征相交系数的方法,改进FERN分类器的第一级方差分类器;还提出一种自适应坐标系的方法,缩小了检测模块扫描窗口的滑动区域。通过仿真实验证明,相对于原算法,这一改进算法在客观评价指标和主观视觉效果上都有明显提高。

基于直接法和特征法的融合实时双目SLAM系统

为了实时获取城市楼宇三维模型,以及估计楼宇遮蔽对目标探测的影响,构建了基于直接法和特征法的融合实时双目同步定位和地图构建(SLAM)系统。该系统主要由前端追踪、局部建图和闭环检测3个部分组成。前端追踪在无人机做有速运动时,采用直接法估计当前帧位姿;若直接法失败或无人机近似静止时,采用基于极线和三角测量精度2种约束条件的特征法估计当前帧位姿。局部建图和闭环检测部分采用随机蕨(Fern)模型构建查询数据库,从而简化了查询数据库的构建流程。在EuRoC开源数据集下进行了系统有效性验证,并与快速特征点提取描述(ORB)-SLAM2开源系统进行了试验对比分析。试验结果表明,该系统减少了追踪耗时,提高了定位精度,增强了系统实时性与鲁棒性。