Control of preharvest and postharvest fruit rot in Strawberry by Metschnikowia fructicola

The yeast Metschnikowia fructicola was tested as a preharvest treatment to control preharvest and postharvest rots of strawberry fruit in Turkey and Israel. In greenhouse trials, the efficacy of the yeast antagonist against preharvest rots was equal to that of a chemical control (fenhexamid) in two growing seasons. In an open-field experiment, the yeast reduced the incidence of rot to commercially acceptable levels. M. fructicola reduced the incidence of fruit rot by 56-69% in greenhouses, open-field culture, and in low plastic tunnels. The yeast suppressed postharvest incidence of fruit rot significantly better than fenhexamid. Among fruit from greenhouses, open-field culture, or tunnels, M. fructicola treatment reduced the incidence of fruit rot during postharvest storage by 70, 64, and 72%, respectively. When applied weekly in the greenhouse or in the field, the population density of M. fructicola was about 1×10⁵ cfu/fruit. Similar population density of the antagonist was also observed during storage of the fruit at 0° C.     

基于多基因分析对我国红曲霉属Monascus真菌的系统发育研究

红曲霉属Monascus具有重要的经济和生态价值,但对该属的物种识别和系统发育学研究有限。本研究首先对红曲霉属红色组内物种开展ITS和LSU序列的测定并综合分析,结合GenBank中相关物种序列及菌株的形态学特征,探讨红曲霉属的系统发育关系,鉴定出红色组3个种,弗罗里达组7个种。其次采用红曲霉色素表型控制基因簇部分基因pksKS序列进行分析,以期解决ITS和LSU等基因序列分析无法有效区分红色红曲与紫色红曲不同形态种的问题。通过分子克隆测序与直接测序结果的比较,以及对3个血红红曲菌株单核苷酸多态性的分析,解析了血红红曲种内遗传差异,首次在红曲霉属真菌中发现疑似红色红曲血红自然杂交种。最后综合ITS、LSU、pksKS序列和形态学分析的结果,统一了红曲霉属内物种的系统发育关系,确认红色组包括3个种：红色红曲M. ruber、紫色红曲M. purpureus、血红红曲M. sanguineus;发现3个变种：红色红曲发白变种M. ruber var. albidulus、紫色红曲橙色变种M. purpureus var. aurantiacus及紫色红曲火红色变种M. purpureus var. rutilus;弗罗里达组包括7个种：弗罗里达红曲M. floridanus、苍白红曲M. pallens、新月红曲M. lunisporas、阿根廷红曲M. argentinensis、累西腓红曲M. recifensis、黄色红曲M. flavipigmentosum、蜂蜜红曲M. mellicola。另外,发现1个疑似杂交种：红色红曲血红杂种M. ruber × sanguineus。结果表明,红曲霉属具有丰富的物种多样性,而且通过多基因和形态学分析可以将相近种区分开来。     

果生刺盘孢CfHAC1调控应答二硫苏糖醇胁迫的转录组分析

果生刺盘孢Colletotrichum fructicola是油茶炭疽病优势病原菌。前期研究发现bZIP转录因子CfHac1参与调控该菌的生长发育和致病性。为了揭示转录因子CfHac1调控果生刺盘孢响应内质网压力和致病机理,本研究测定了ΔCfhac1突变体对内质网压力胁迫剂的敏感性,发现突变体对二硫苏糖醇（dithiothreitol,DTT）的耐受性下降,说明CfHAC1基因可能参与调控果生刺盘孢响应内质网压力胁迫过程。进一步利用高通量RNA-seq技术对该病菌野生型菌株和CfHAC1敲除突变体菌株在DTT胁迫下的转录组进行了比较分析,结果表明差异表达基因共有2 680个,其中上调表达基因有1 181个,下调表达基因有1 499个。Gene Ontology 功能分析结果显示,差异表达基因主要参与催化活性、结合、代谢过程、细胞过程、细胞成分合成、生物过程调控和应激反应等生物学过程。KEGG功能富集分析表明,上调表达基因主要被富集到核糖体、真核细胞的核糖体生物合成、RNA转运和氰基氨基酸代谢通路中;下调表达基因显著富集在内质网蛋白质加工、N-聚糖生物合成、类固醇合成和蛋白质分泌等通路中。分析发现转录因子CfHac1调控内质网胁迫应答和致病相关基因的表达。本研究提供了在全基因组水平上对CfHAC1基因与内质网压力胁迫应答之间关联的新认识,为阐明果生刺盘孢响应内质网压力胁迫和致病机制奠定了基础。     

bZIP转录因子CfHac1参与调控果生刺盘孢菌的生长发育和致病力

油茶炭疽病是油茶Camellia oleifera上最重要病害之一,引起该病害的主要致病菌为果生刺盘孢菌Colletotrichum fructicola。本研究以果生刺盘孢菌bZIP类转录因子CfHac1为研究对象,研究其在果生刺盘孢菌的营养生长、产孢量、附着胞形成、致病力及耐受性等方面的生物学功能,为油茶炭疽病的防控提供理论依据。研究结果表明,果生刺盘孢菌中具有一个与灰色大角间座壳（稻瘟菌）bZIP转录因子MoHac1直系同源的基因,命名为CfHAC1。该基因全长1 627bp,编码526个氨基酸,该蛋白含有一个碱性亮氨酸链（bZIP）结构域和3个未知功能结构域。CfHAC1基因敲除突变体的菌丝生长速度显著变慢,分生孢子产量显著减少且不能正常形成附着胞,并对山梨糖醇和KCl渗透压胁迫敏感性增加;致病力测试结果表明,果生刺盘孢菌基因敲除突变体ΔCfhac1对油茶的致病力显著下降。转录因子CfHac1参与调控果生刺盘孢菌的生长、产孢、附着胞的形成、致病力以及响应外界渗透压胁迫过程。     

Selection and preliminary characterization of β-glycosidases producer Patagonian wild yeasts

Four pre-selected indigenous yeast strains belonging to Candida guilliermondii (V₂ and V₅), Candida pulcherrima (V₆) and Kloeckera apiculata (V₉), were used as β-glucosidase (βGL) and β-xylosidase (βXL) sources. The optimization of yeast culture conditions was carried out and the effects of oenological parameters on β-glycosidase activities were evaluated. C. guilliermondii V₂ and C. pulcherrima V₆ strains were selected. These strains showed intracellular (C. pulcherrima V₆) and parietal (C. guilliermondii V₂) constitutive βGL and βXL. The enzymatic activities were active at pH, glucose, ethanol and SO₂ concentrations usually found in winemaking and they were able to release monoterpenols and alcohols from grape juice glycoside extracts. Additionally, these yeast strains were not able to produce volatile acidity and off flavour. Regional ecological relevance of these species was also discussed. Our results evidence that the selected C. guilliermondii V₂ and C. pulcherrima V₆ strains have interesting oenological characteristics and allow us to think in their potential application in winemaking.     

Enzyme polymorphism in three species of Metanephrops (Decapoda: Nephropidae) from Taiwan

Electrophoretic analysis of 22 genetic Loci coding for 17 enzymes was used to investigate relationships among three species of Metanephrops (M. thomsoni M. formosanus and M. japonicus var) from Taiwan. Eleven Ioci are identically monomorphic in the three species. Only one Iocus Sdh was diagnostic for identification of the three species. Electrophoretically detectable variation was confined to three species of Metanephrops with Iow frequency — the unique alleles of ALk, Gdh, Gpi, Me-1 and 6-Pgdh. The proportion of polymorphic loci (0.95 level) ranged from 0.047 to 0.091 and expected average heterozygosity 0.0043–0.0232. Estimates of Nei's genetic distances between the three species suggest that M. formosanus and M. japonicus var. are closely related.     

Population genetics and evolutionary history of Miscanthus species in China

Miscanthus species have received considerable attention as a potential biomass source for renewable energy production because of their ability to produce high yields of biomass and adapt to a wide range of climates and soils. To explore the genetic diversity and phylogenetic relationship of Miscanthus species in China, we used 24 simple sequence repeat markers to genotype 100 natural populations representing all four Chinese Miscanthus species (M. sinensis Andersson, M. floridulus (Lab.) Warb. ex K. Schum. & Lauterb., M. sacchariflorus (Maxim.) Hack., and M. lutarioriparius L. Liu ex Renvoize & S. L. Chen). Based on phylogenetic, principal coordinate, and Structure analyses, we found that the 100 populations formed two major groups corresponding to sect. Triarrhena and sect. Miscanthus. Group 1 (i.e., sect. Triarrhena) was further subdivided into two subgroups corresponding to M. sacchariflorus and M. lutarioriparius; Group 2 (i.e., sect. Miscanthus) was subdivided into three subgroups, group 2a (M. sinensis populations in southern China), group 2b (M. sinensis populations in northern China), and group 2c (all the M. floridulus populations). Population genetics analyses indicated high levels of the genetic diversity at both population (H_E = 0.468–0.599) and species (H_E = 0.559–0.708) levels, indicative of the potential of these wild resources in future breeding programs. The species distribution modeling showed that M. sacchariflorus and M. lutarioriparius have experienced population reductions during the last glacial maximum and population expansion afterward; in contrast, M. sinensis and M. floridulus both underwent gradual population expansions from the last interglaciation to the present. We also suggest that M. floridulus originated from M. sinensis in southeast China through ecological speciation. The understanding of the evolutionary history and population dynamics of these species not only provides valuable information for further genetic improvement and breeding of this energy crop but also gives important insights into the origin and speciation processes of the Miscanthus species.     

Africa goes Europe: The complete phylogeography of the marbled white butterfly species complex Melanargia galathea/M. lachesis (Lepidoptera: Satyridae)

Climatic oscillations influence the distribution of species in time. Thermophilic species survived the ice ages in refugia around the Mediterranean. Northern Africa is one of the possibly important refugia. In this study we test the genetic differentiation between northern African and European populations, using the marbled white butterfly species complex, Melanargia galathea/M. lachesis, as a model. We studied 18 allozyme loci in 876 individuals from 23 populations representing a major part of Europe (northern Spain to Romania) and the western part of northern Africa (Atlas Mountains). The African populations resemble the European ones in allelic richness; their genetic diversity is higher than in Europe. Cluster analysis discriminated five European genetic groups: M. lachesis, a western European lineage, and three eastern European lineages. However, the African samples did not form a separate cluster within this phenogram, but clustered randomly within the Balkan/southeastern European groups. The genetic differentiation among the African populations (F_ST 8.8%) was higher than that within any of the European lineages (F_ST 2.6–5.5%). The high genetic diversity and the relatively strong differentiation of the four African populations sampled in a comparatively limited area of the Atlas Mountains indicate that the most probable origin of M. galathea is northern Africa, with its sibling species, M. lachesis, evolving in parallel in Iberia. Most probably, M. galathea colonised Europe first during the Eem interglacial, some 130 ky ago. Since M. lachesis must have existed on the Iberian peninsula during that period already, M. galathea should have reached Europe via Italy. The genetic differentiation to distinct groups in Europe most probably evolved during the following Würm glacial period.     

Mass-spectrometry based minisequencing method for the rapid detection of drug resistance in Mycobacterium tuberculosis

A MALDI TOF MS based minisequencing method has been developed and applied for the analysis of rifampin (RIF)- and isoniazid (INH)-resistant M. tuberculosis strains. Eight genetic markers of RIF resistance-nucleotide polymorphisms located in RRDR of rpoB gene, and three of INH resistance including codon 315 of katG gene and − 8 and − 15 positions of the promoter region of fabG1-inhA operon were worked out. Based on the analysis of 100 M. tuberculosis strains collected from the Moscow region in 1997–2005 we deduced that 91% of RIF-resistant and 94% of INH-resistant strains can be identified using the technique suggested. The approach is rapid, reliable and allows to reveal the drug resistance of M. tuberculosis strains within 12 h after sample isolation.     

Serotiny and seed germination in three threatened species of Mammillaria (Cactaceae)

Individuals of some species of Mammillaria (Cactaceae) store some seeds on the plant over periods exceeding 1 year (serotiny). We examined the phenomenon of serotiny and germination behaviour of three rare and endangered Mammillaria species that occur in central Mexico. The species with the highest seed retention was Mammillaria solisioides, whose individuals kept on average 24% of their total seed crop throughout their observable lifetime. Individuals of Mammillaria napina and Mammillaria hernandezii did not differ in their degree of seed retention (about 5%). In M. solisioides and M. hernandezii, seed germination declined significantly with seed age, whereas in M. napina germination increased slightly. In all three species, over 70% of retained seeds were still alive after 8 years. Increasing fractions of dormant seeds were observed with seed age in M. solisioides and M. hernandezii, whereas in M. napina this fraction followed the opposite trend. All three species showed strict light dependence for germination. Serotiny was positively correlated with the harshness of the environment when species and populations were assumed independent. However, these correlations were not significant at the 5% level when the degree of relatedness of species and populations was taken into account using phylogenetically independent constrasts. We hypothesise that serotiny in these species represents a mechanism by which they can cope with a harsh, unpredictable environment. To our knowledge, this is the first assessment of serotiny in cacti.     

Systematics of Mukdenia and Oresitrophe (Saxifragaceae): Insights from genome skimming data

Oresitrophe and Mukdenia (Saxifragaceae) are epilithic sister genera used in traditional Chinese medicine. The taxonomy of Mukdenia, especially of M. acanthifolia, has been controversial. To address this, we produced plastid and mitochondrial data using genome skimming for Mukdenia acanthifolia and Mukdenia rossii, including three individuals of each species. We assembled complete plastomes, mitochondrial CDS and nuclear ribosomal ETS/ITS sequences using these data. Comparative analysis shows that the plastomes of Mukdenia and Oresitrophe are relatively conservative in terms of genome size, structure, gene content, RNA editing sites and codon usage. Five plastid regions that represent hotspots of change (trnH-psbA, psbC-trnS, trnM-atpE, petA-psbJ and ccsA-ndhD) are identified within Mukdenia, and six regions (trnH-psbA, petN-psbM, trnM-atpE, rps16-trnQ, ycf1 and ndhF) contain a higher number of species-specific parsimony-informative sites that may serve as potential DNA barcodes for species identification. To infer phylogenetic relationships between Mukdenia and Oresitrophe, we combined our data with published data based on three different datasets. The monophyly of each species (Oresitrophe rupifraga, M. acanthifolia and M. rossii) and the inferred topology ((M. rossii, M. acanthifolia), O. rupifraga) are well supported in trees reconstructed using the complete plastome sequences, but M. acanthifolia and M. rossii did not form a separate clade in the trees based on ETS + ITS data, while the mitochondrial CDS trees are not well-resolved. We found low recovery of genes in the Angiosperms353 target enrichment panel from our unenriched genome skimming data. Hybridization or incomplete lineage sorting may be the cause of discordance between trees reconstructed from organellar and nuclear data. Considering its morphological distinctiveness and our molecular phylogenetic results, we strongly recommend that M. acanthifolia be treated as a distinct species.     

基于孢子形态和分子证据探讨鳞盖蕨属(碗蕨科)系统分类

孢粉学是解决植物分类中疑难类群物种微形态分化的重要方法, 随着分子系统学的发展, 结合这两门学科的优势可以更加有效地解决疑难类群的分类学问题。鳞盖蕨属(Microlepia)是一个分类困难的疑难类群, 采用孢粉学与分子系统学一一对应的方法, 以及居群取样方式, 选取280份样本, 联合4个叶绿体片段(rbcL、trnL-F、psbA-trnH和rps4), 采用最大似然法和贝叶斯法构建该属的系统发生关系, 在此基础上对凭证标本中100份材料的孢子进行观察和分析。综合分子系统学和孢粉学的研究结果, 得出结论: (1) 在形态学研究中广泛被接受的15个物种得到了单系支持, 并厘清了分类困难的复合群; (2) 发现边缘鳞盖蕨(M. marginata)可能存在隐性种; (3) 建议恢复过去归并处理为异名的瑶山鳞盖蕨(M. yaoshanica)、罗浮鳞盖蕨(M. lofoushanensis)、四川鳞盖蕨(M. szechuanica)以及滇西鳞盖蕨(M. subspeluncae); (4) 提出鳞盖蕨属可能存在杂交现象; (5) 提出鳞盖蕨属完整的属下分类建议。     

麂属(Muntiacus)的分类及其系统发育研究

麂属(Muntiacus)是一群中小型草食有蹄类,为东洋界的特有属,是典型的热带、亚热带类群。在我国,麂属的分布仅限于长江流域及其以南各地,为我国南方的重要毛皮兽。 以往对麂属的研究多限于一般的形态分类,对其系统发育尚未深入研究。在种级分类上至今还存在一些混乱现象。本文试图用分支系统学(Cladistics)的方法,对麂属的种级分化进行系统整理,并对其系统发育作一初步探讨。     

组蛋白去乙酰化酶CfSnt2调控果生刺盘孢生长发育和致病力

炭疽病是油茶Camellia oleifera的重要病害,该病害的优势致病菌是刺盘孢属Colletotrichum的果生刺盘孢C. fructicola,在全国的油茶产区普遍发生。我们前期发现组蛋白乙酰转移酶CfGcn5调控油茶果生刺盘孢的生长发育和致病过程,但组蛋白去乙酰化酶在该病菌中的生物学功能尚不清楚。本研究以组蛋白去乙酰化酶CfSnt2为研究对象,利用反向遗传学的方法,通过对野生型、CfSNT2基因敲除突变体及互补菌株的生物学表型进行比较分析,发现CfSNT2基因敲除突变体的菌丝生长速率明显减缓、分生孢子的产量显著减少、附着胞形成率降低、对细胞壁胁迫剂的响应异常,同时对油茶致病力显著减弱。以上现象说明CfSnt2调控果生刺盘孢的生长、产孢、附着胞的形成、对细胞壁完整性胁迫剂的耐受性及致病力。     

中国巢鼠属分类与分布的讨论

巢鼠属（Micromys Dehne,1841）隶属于啮齿目（Rodentia）鼠科（Muridae）,是最小的啮齿动物之一。此前的研究显示该属包含巢鼠（M.minutus）和红耳巢鼠（M.erythrotis）两个物种,但由于数据缺乏,红耳巢鼠的有效种地位仍存争议,且两个物种在中国的地理分布也不确定。本研究在安徽清凉峰国家级自然保护区采集到一批巢鼠属标本,经形态与分子学鉴定发现其包含巢鼠和红耳巢鼠两个物种,它们在清凉峰海拔1 600 m处同域分布,支持红耳巢鼠的有效种地位。基于安徽清凉峰巢鼠和红耳巢鼠的外形特点,本文对国家动物标本资源库的巢鼠属照片进行了分析,并结合相关文献资料,对中国巢鼠属的地理分布进行了整理,同时绘制了地理分布图。结果显示：在我国巢鼠主要分布在黑龙江、吉林、辽宁、内蒙古、河北、陕西、甘肃、新疆、江苏、安徽、浙江、湖南、江西、广东、福建、台湾;红耳巢鼠主要分布在云南、四川、陕西、湖北、西藏、贵州、重庆、安徽、福建、广西;两者在安徽清凉峰和陕西镇巴县、城固县皆有分布。此外,分子系统学分析显示,我国巢鼠属多样性仍被低估,极有可能存在未知的分类单元,巢鼠属的分类研究工作仍需加强。     

Cryptococcus zeae, a new yeast species associated with Zea mays

A new yeast, Cryptococcus zeae (type strain HB 1207^T) is described. Six strains were isolated from corn and pests of corn in Austria. Microsatellite-primed polymerase chain reaction (MSP-PCR) fingerprints showed that the strains are members of the same species. Phylogenetical analyses of domains D1/D2 26S rDNA and ITS 1-5,8S–ITS 2 sequences showed C. zeae to have the closest relationship to C. luteolus. The D1/D2 sequences of C. zeae fit with three Korean Cryptococcus sp. strains (AF459690, AF459691, AF459692). The new species is separable from the closest relative C. luteolus using only two physiological tests.     

林冠环境对润楠幼苗构型和生物量分配的影响

植物幼苗早期适应对策对种群的更新具有决定性的作用。润楠(Machilus nanmu)是国家Ⅱ级保护植物,是重庆缙云山常绿阔叶林优势乔木树种之一。研究润楠幼苗的适应对策对于维持种群更新和保护常绿阔叶林生物多样性具有重要意义。本研究采集了重庆缙云山常绿阔叶林中不同林冠环境(林窗/林下)下不同年龄阶段(阶段1: 1～3年;阶段2: 4～6年;阶段3: 7～9年)的润楠幼苗,从构型和生物量分配角度研究其早期适应对策的时间动态及其对异质生境的响应。结果表明: 林窗中润楠幼苗的茎构型各指标(除枝倾角)和叶倾角在阶段2和阶段3显著大于林下,根构型各指标(除根直径)和叶面积在阶段1和阶段2显著大于林下;而林窗中润楠幼苗的比叶面积在3个阶段均显著小于林下。不同林冠环境和年龄阶段的生物量分配均以叶为主,但林窗中润楠幼苗从阶段2开始增加了茎的生物量分配,减少了根的生物量分配,林下润楠幼苗根的生物量分配则无显著变化。润楠幼苗各器官的协调性随生境条件不同产生适应性进化,即林窗中润楠幼苗的根与叶之间显著相关,且此相关关系随年龄增大由正到负;林下润楠幼苗的根和茎呈显著正相关,根和叶之间无显著相关。不同林冠环境下润楠幼苗枝干重与枝长的标准化主轴回归(SMA)方程斜率仅在阶段3差异显著,而叶、根生物量与构型间的SMA方程斜率的差异均不显著;大部分生物量与构型间的SMA方程截距在阶段2差异显著。     

新古尼异虫草内菌核的多菌定殖现象

基于高通量测序技术,对采自中国江西省宜丰县杨柳镇、贵州省石阡县白沙镇、贵州省湄潭县、贵州省凤岗县和贵州省施秉县5个不同地区的新古尼异虫草Metacordyceps neogunnii的真菌生态位进行研究。结果显示,新古尼异虫草生境土壤、菌表及其内菌核的真菌类群共涉及子囊菌门Ascomycota、担子菌门Basidiomycota、接合菌门Zygomycota、类原生动物门Rozellomycota 4个门及一些未定门的真菌;共17纲、43目、77科、129个属的177种真菌。在属的水平上,新古尼异虫草生境土壤（Cg1）的优势属为被孢霉Mortierella,相对丰度为84.86%,其次是分类地位未定的真菌（4.58%）,毛壳菌科Chaetomiaceae 1属（1.22%）;虫草菌表（Cg2）的优势属或种为新古尼异虫草M. neogunnii（83.66%）,其次是粉红螺旋聚孢霉Clonostachys rosea（9.48%）,帚枝霉属Sarocladium（2.07%）和被孢霉属（1.12%）。而来自江西（JX）、石阡（SX）、凤岗（FG）、施秉（Cg3）4个不同地区的新古尼异虫草样本的内菌核优势属真菌均为新古尼异虫草,其相对丰度分别为：99.74%、99.50%、99.73%和98.82%,其余属相对丰度均小于1%。来自湄潭的干标本内菌核优势属为麦角菌科Clavicipitaceae的一个未定属,相对丰度则高达99.97%。综上结果表明,来自5个不同地区的新古尼异虫草种群的内菌核中不仅是新古尼异虫草M. neogunnii,同时有其他真菌存在。施秉样本周围的土壤真菌群落较虫草样本内菌核具明显的多样性。但有趣的是,采集虫草的土壤中不含新古尼异虫草,而具有相对丰度较大的被孢霉Mortierella spp.和木霉Trichoderma spp.。来自湄潭的干标本,不含新古尼异虫草而是相对丰度较高的麦角菌科Clavicipitaceae一未知成员,其分类地位值得进一步研究。     

水杉原生种群结构及空间分布格局

水杉(Metasequoia glyptostroboides)是我国特有濒危极小种群物种, 其种群的状态一直被国内外学者广泛关注。分析现存水杉原生种群结构和空间分布格局及其空间关联性, 可以从空间格局角度深入认识水杉原生种群结构和分布格局及可能的形成机理。本文基于湖北利川境内水杉原生种群的野外调查数据, 分析其径级和高度级结构, 同时运用点格局分析中的成对相关函数g(r)以及3个零模型(完全空间随机模型、异质泊松模型、先决条件模型)分析水杉原生种群空间分布格局、各龄级空间分布格局及空间关联性。结果表明: (1)分布于研究区域内的水杉原生种群个体数共5,663株, 已死亡33株, 现存活5,630株, 其中40株濒临死亡, 465株处于衰弱状态, 部分个体呈现不同的形态特征和生长状况, 断梢和蚁害最为常见, 雷击是最致命的危害。(2)水杉原生种群结构分析显示, 其径级结构和高度级结构均呈纺锤型, 自然更新不良。(3)基于完全空间随机模型, 水杉原生种群在各尺度下均呈现聚集分布, 中龄树在较小尺度(r < 3,300 m)上呈现聚集分布, 成年树和老龄树在较大尺度(r < 4,700 m)上呈现聚集分布; 排除生境异质性影响后, 聚集尺度均减小, 所以种群及不同龄级的聚集尺度分别为0-3,000 m、0-2,100 m、0-2,900 m和0-2,500 m, 随后呈现为微弱的随机分布和均匀分布。(4)基于完全空间随机模型, 3个龄级之间在所有尺度均为正关联; 在排除生境异质性影响后, 不同龄级的正关联尺度减小, 均在0-2,800 m呈正关联。综上, 水杉原生种群个体数量正呈现逐步减少的趋势, 种群主要呈聚集分布, 各个龄级间具有正向的关系, 从现有的空间格局来看, 生境异质性、扩散限制和种内竞争是导致该格局的主要原因。     

小口盘菌属一新种及该属分种检索表

本文报道了采自内蒙古地区的肉杯菌科一新种：根小口盘菌Microstoma radicatum。提供了新种的详细描述、生态照片、线条图和ITS序列GenBank登录号,编制了小口盘菌属世界已知种的分种检索表。研究标本保存在赤峰学院菌物标本室（CFSZ）和中国科学院菌物标本馆（HMAS）。