Species composition and correlation of understory woody plants in Chinese fir plantation in the lower subtropical area

There are 71 species in the shrub layer of the Cunninghamia lanceolata plantation after natural succession. The species richness and diversity have increased with slight anthropogenic disturbance. The status and function of understory woody species were judged by the analysis of the important value (IV). x ² statistics and r test were used for testing the significance of interspecific association and correlation among 25 main understory woody plants selected from the woody population. The results clearly showed their interspecific relationships and their differences in resource utilization. Species-pairs of positive association were in the majority. Most species were accommodated in the shady habitat. There was a positive correlation between the IV of the species and the interspecific association. The higher the IV of the species, the closer and more significant was the interspecific association. Based on analytical results of interspecific association and correlation, 25 woody plants in the shrub layer could be divided into four ecological species groups: I. Ficus hispida + Antidesma bunius + Mallotus barbatus + Ficus cunia + Saurauia tristyla + Mallotus philippinensis + Maesa japonica + Ficus hirta + Alchornea rugosa + Ficus fulva + Mallotus apelta; II. Cudrania tricuspidata + Schefflera octophylla; III. Cunninghamia lanceolata + Clerodendron cytophyllum + Millettia semicastrata + Randia spinosa + Litsea cubeba + Litsea pungens; IV. Ardisia japonica + Psychotria rubra + Vitex quinata + Cephalanthus occidentalis + Pithecellobium lucidum + Mycetia sinensis. If species group III or II is the advantaged species in the shrub layer, the community would change from a coniferous forest to a sparse evergreen broad-leaved forest. For group IV, the community would be relatively stable. For group I, the coniferous forest would be mixed with coniferous-broad leaved forest. The classification of ecological species groups would provide a theoretical basis on judging its ecological function, adjusting the stand structure of the plantation and directing the suitable natural vegetation type through the close-natural restoration process. __________ Translated from Acta Ecologica Sinica, 2005, 25(9): 2173–2179 [译自: 生态学报, 2005, 25(9): 2173–2179]     

放牧藏猪、舍饲藏猪与商品猪粪便真菌群落组成及其与饲粮纤维消化的相关性研究

【目的】研究饲养在西藏高原的放牧藏猪、舍饲藏猪和商品猪(杜长大猪,DLY猪)粪便中真菌群落组成的差异性,获取与饲粮粗纤维消化相关的真菌群落。【方法】以饲养在西藏高原的5月龄放牧藏猪、舍饲藏猪和DLY猪为研究对象,采用消化试验测定放牧藏猪、舍饲藏猪和DLY猪对饲粮粗纤维的表观消化率。采集粪便样品利用单分子实时测序技术(SMRT),测定粪便真菌ITS基因全长序列,分析粪便真菌群落的结构和多样性,采用Pearson相关分析获取饲粮粗纤维表观消化率与真菌群落的相关性。【结果】在放牧藏猪、舍饲藏猪和DLY猪的粪便样品中共鉴定出了4个门、13个纲、23个目、39个科、55个属、58个种,放牧藏猪在各分类水平的分类单元数均显著高于舍饲藏猪与DLY猪(P<0.05)。子囊菌门(Ascomycota)和担子菌门(Basidiomycota)是优势菌门,在门水平下,放牧藏猪、舍饲藏猪和DLY猪间无显著差异(P≥0.05),但在纲、目、科、属、种水平下,放牧藏猪多个真菌类群相对丰度显著高于舍饲藏猪与DLY猪(P<0.05)。放牧藏猪具有更高的菌群丰富度和独有分类操作单元(OTU)(P<0....     

米槁根际土壤真菌多样性及其与果实药用活性成分含量的相关性分析

为了解不同产地米槁Cinnamomum migao根际土壤真菌多样性及其差异,探讨米槁活性成分、土壤理化因子与其土壤真菌群落的联系。本文采用高通量测序技术对云南、贵州及广西的9个产点米槁根际土壤真菌群落组成和结构进行分析,测定不同产地米槁的主要活性成分及土壤理化因子,同时对米槁活性成分及其与土壤理化因子和根际土壤真菌种群多样性进行相关性分析。结果表明,米槁根际土壤真菌物种可归入8门、30纲、89目、200科、440属,优势类群为一未能分类的属,相对丰度为18.76%,其次为被孢霉属Mortierella（16.37%）等;不同产地米槁根际土壤真菌群落组成存在差异,最高多样性指数出现在贵州罗甸,随后依次为贵州望谟、广西乐业、广西天峨、贵州册亨、贵州荔波、云南富宁、云南那坡、贵州贞丰;总体而言,广西乐业、贵州望谟和广西天峨3地米槁果实样本活性成分1,8-桉叶素（1,8-cineole）、香桧烯（sabinene）、柠檬烯（limonene）和α-松油醇（α-terpineo）的含量均高于其他样本;冗余分析（redundancy analysis,RDA）结果表明,部分真菌类群与米槁药用活性成分呈正相关。     

不同产地杜仲根际土真菌群落结构的差异性分析

基于宏条码技术对采自贵州遵义县、湖南慈利县和四川旺苍县3个杜仲产地根际土壤的真菌群落组成进行了分析。研究获得根际土壤真菌有效序列共10 775条,聚类后OTUs对应的真菌类群涉及子囊菌门Ascomycota、担子菌门Basidiomycota、接合菌门Zygomycota、球囊菌门Glomeromycota、壶菌门Chytridiomycota、类原生动物门Rozellomycota的22纲、59目、103科、108个属的550个真菌分类单元(OTUs)。在属的水平上,湖南慈利样本(ECS)有119个属,优势属为镰刀菌属Fusarium,相对丰度为16.31%,其次是被孢霉属Mortierella(14.67%)、毛壳菌科Chaetomiaceae一未定属(13.01%)和木霉属Trichoderma(11.37%)等。四川旺苍样本(EWS)共有116个属,优势属为丝齿菌属Hyphodontia,相对丰度32.32%,其次为镰刀菌Fusarium(13.41%)等。贵州遵义样本(EZS)有110个属,优势属为被孢霉属Mortierella,相对丰度30.74%,其次是木霉属Trichoderma(25.96%)和镰刀菌属Fusarium(4.85%)等。α多样性分析表明,不同产地杜仲根际土壤真菌群落组成有明显差异。遵义样本(EZS)、慈利样本(ECS)和旺苍样本(EWS)的Shannon多样性指数从高到低为:ECS(2.7661)> EZS(2.4841)>EWS(2.1326)。不同杜仲产区土壤理化因子及4个主要活性成分(松脂醇二葡萄糖苷、绿原酸、京尼平苷酸和京尼平苷)与根际土真菌群落组成的相关性分析表明,4个主要活性成分皆为四川旺苍(EWS)产地含量最高,其次是湖南慈利,贵州遵义最低甚至不含京尼平苷。杜仲根际土壤样品真菌物种组成丰富,不同地区杜仲根际土壤真菌群落组成、分类单元的相对丰度及优势分类单元皆存在不同程度差异。杜仲根际土真菌群落结构的多样性与土壤理化因子及杜仲主要有效成分含量具有一定相关性。杜仲根际土真菌群落组成的结构谱是杜仲道地性的重要特征。     

月季F1代群体表型性状变异分析

以月季（Rosa spp.）品种‘云蒸霞蔚’和‘太阳城’正交获得的184株F₁代群体为研究对象,采用方差分析、变异系数、遗传分析、相关性分析对花部形态性状以及叶片形态性状进行测定分析。结果表明：该杂交群体表型变异丰富,变异系数在7.33%~68.08%,其中花瓣数量在群体中的变异程度最高;杂交后代各个性状上均发生分离变异,出现不同于亲本的表现型,且离散程度较高。表型性状的遗传特点与关联分析,为挖掘控制表型性状的优良基因及辅助选择育种提供参考。     

云南松苗木生长与生物量的相关性及通径分析

为了解云南松苗木生长对生物量的影响程度和相对重要性,以采自云南省昆明市宜良县禄丰村林场种子培育的2年生云南松苗木为材料,对苗高、地径、主根长、侧根长、针叶长和侧根数6个生长性状及各组分生物量进行测定,运用相关性分析和逐步回归分析剔除了对生物量影响不大的性状,在此基础上采用通径分析方法研究了云南松苗木生长性状指标与生物量指标间的关系。结果表明：云南松苗木生长性状和生物量之间均呈现极显著的正相关关系。各生长性状对生物量均有直接或间接的正向效应,直接影响云南松苗木生物量的优势因素为地径和苗高,针叶长、侧根长和主根长对生物量的影响也起正向效应。各生长性状对生物量的直接效应均较大,而通过其他性状的间接效应均较小,其中侧根长通过其他性状对生物量产生的间接影响最大。依据相关性分析和通径分析,建立了云南松各组分生物量与生长性状之间的数学模型,可用于云南松苗期生物量的估测。     

Surface analysis of sheep menisci after meniscectomy via infrared attenuated total reflection spectroscopy

Menisci are very important fibrocartilaginous tissue, which maintain biomechanical functions and physiological stabilization of knee joint. Meniscectomy is known as a surgery to recover partial functions from acute meniscus tears. However, the late consequences of total or partial meniscectomy include signs of osteoarthritis and even ligament instability. Infrared attenuated total reflection (IR‐ATR) spectroscopy is a very useful technique, which can reveal molecular characteristics via the analysis of vibrational bands. The present study has employed IR‐ATR spectroscopy to investigate sheep menisci samples after meniscectomy in a label‐free fashion. Several differences of peak absorbance change and peak shift were observed between the native healthy samples and the meniscectomy samples in distinct IR wavenumber regions, such as amide I band, amide II band, C‐H bending band as well as the sugar band region. Combining the results from the collagen protein IR spectra, it can be speculated that six months after meniscectomy collagen fibrils on the incision lose its ordered arrangement and a decrease in the triple helical structure of collagen fibril is observed. In addition, the collagen fibrils and proteoglycan content might also be slight varied after meniscectomy.      

Heterozygosity at neutral and immune loci is not associated with neonatal mortality due to microbial infection in Antarctic fur seals

Numerous studies have reported correlations between the heterozygosity of genetic markers and fitness. These heterozygosity–fitness correlations (HFCs) play a central role in evolutionary and conservation biology, yet their mechanistic basis remains open to debate. For example, fitness associations have been widely reported at both neutral and functional loci, yet few studies have directly compared the two, making it difficult to gauge the relative contributions of genome‐wide inbreeding and specific functional genes to fitness. Here, we compared the effects of neutral and immune gene heterozygosity on death from bacterial infection in Antarctic fur seal (Arctocephalus gazella) pups. We specifically developed a panel of 13 microsatellites from expressed immune genes and genotyped these together with 48 neutral loci in 234 individuals, comprising 39 pups that were classified at necropsy as having most likely died of bacterial infection together with a five times larger matched sample of healthy surviving pups. Identity disequilibrium quantified from the neutral markers was positive and significant, indicative of variance in inbreeding within the study population. However, multilocus heterozygosity did not differ significantly between healthy and infected pups at either class of marker, and little evidence was found for fitness associations at individual loci. These results support a previous study of Antarctic fur seals that found no effects of heterozygosity at nine neutral microsatellites on neonatal survival and thereby help to refine our understanding of how HFCs vary across the life cycle. Given that nonsignificant HFCs are underreported in the literature, we also hope that our study will contribute toward a more balanced understanding of the wider importance of this phenomenon.     

两种荒漠豆科植物化学计量特征与生境土壤因子的关系

豆科植物是荒漠等干旱生态系统的重要先锋物种,也是生态系统中有效氮的主要来源。为了明确荒漠豆科植物与生境土壤因子之间的关系,该研究以古尔班通古特沙漠广泛分布的荒漠豆科植物弯花黄芪(Astragalus flexus)、镰荚黄芪(Astragalus arpilobus)为对象,测定不同土壤深度(0~5、5~10、10~15 cm)的理化性质,比较分析2种荒漠豆科植物化学计量特征与土壤因子的关系。结果表明:(1)弯花黄芪碳(C)、氮(N)、磷(P)含量分别为373.35、25.66、1.03 mg·g^-1,高于镰荚黄芪的331.53、19.59、0.66 mg·g^-1,且二者的N、P含量均差异显著(P<0.05);弯花黄芪的C∶P、N∶P分别为374.38、25.75,均极显著高于镰荚黄芪的166.09、10.12(P<0.01),而弯花黄芪的C∶N(14.62)低于镰荚黄芪(16.99),两种植物的C和C∶N均无显著差异。(2)豆科植物生境土壤在0~5 cm土层的有机碳(SOC)、全氮(TN)、全磷(TP)含量最高,且随土层的加深逐渐减少;土壤化学计量比SOC∶TN、SOC∶TP均随土层加深逐渐增大,而TN∶TP值随土层加深逐渐减少;较低的N含量及TN∶TP 显示该区域土壤属于N素缺乏类型。(3)2种荒漠豆科植物与各层次土壤化学计量特征的相关性无一致规律。其中,弯花黄芪立地0~10 cm土层的TN与N∶P间呈负相关关系,TP与P间呈极显著负相关关系,而TP与C∶N间呈正相关关系,SOC∶TN与N∶P间呈极显著正相关关系;在10~15 cm土层中,SOC∶TN与N∶P间呈正相关关系。镰荚黄芪中仅P含量与其立地0~5 cm土层的SOC∶TP具有极显著正相关关系,而大部分化学计量特征间未显示出相关性。(4)弯花黄芪的植物化学计量指标P含量与5~10 cm土层的电导率(EC)间呈极显著正相关关系,N含量与10~15 cm土层的速效钾(AK)间呈正相关关系;而镰荚黄芪N、AP与N∶P与0~5 cm土层的速效磷(AP)间均呈极显著负相关关系,与其他土层未出现相关关系。研究认为,古尔班通古特沙漠土壤N含量以及TN∶TP较低,土壤N元素贫瘠,且该区豆科植物立地土壤养分含量总体偏低;该区弯花黄芪生长的主要限制元素为P,而镰荚黄芪生长的主要限制元素为N和P;植物化学计量特征并非全部由土壤养分特征直接决定,其明显的种间差异显示植物自身遗传特性在土壤 植物计量特征耦合关系的重要性。     

秦岭皇冠优势灌木苦糖果的空间分布格局及种内种间关联

以秦岭皇冠暖温性落叶阔叶林25 hm²森林样地中的优势灌木苦糖果为对象,研究了苦糖果不同径级个体的空间分布格局以及种内种间关系。结果表明: 苦糖果径级结构呈现出下宽上窄的金字塔型,小径级植株数量最多,更新状态较好,处于稳定增长阶段,有利于群落更新和演替。以Ripley's K函数为基础,采用单变量和双变量成对相关函数,在3个零模型(完全空间随机模型、异质泊松模型和先决条件模型)的处理下,树种整体和不同径级以聚集分布为主,且聚集程度随研究尺度的加大而逐渐减小,逐渐趋向随机分布。受到生境异质性、扩散限制、负密度制约等影响,种内不同径级个体之间以正关联为主,但也有一定程度的无关联,未出现负关联的情况。种间关系较为复杂,既有无关联,也有正关联和负关联,但以负关联和无关联为主。