巴山松针叶群体数量和寿命的水平与垂直变化趋势分析

根据对巴山松针叶群体的水平和垂直主特征及趋势进行的研究,得到如下结果：（１）单株木的针叶总数和各龄针总数随胸径增加而增多,随密度增加而减少,当年生针叶数量所占比例随径阶增加而增大,２年生针叶比例与此林反,而１年生和３年生针叶比例基本保持稳定。（２）单株木的径阶愈小,针叶平均寿命亦愈长;就针叶平均生存期则言,劣势本最短,成势木次之,而平均木最长。（３）各龄级针叶群体的数量一般在树冠中部所占比例最大,     

锥栗种质资源遗传多样性的SRAP分析

应用SRAP分子标记法,采用筛选出的15个引物组合,对采自湖南、浙江、四川、贵州、福建5省的17个野生锥栗居群资源及23份锥栗栽培品种进行了遗传多样性分析,旨在为锥栗遗传背景分析和种质创新提供依据。17个野生锥栗居群共扩增出221个位点,平均多态性位点数为155.06,多态性位点百分率为70.16%。总遗传多样性指数(Ht)、居群内遗传多样性指数(Hs)、Nei's基因多样性指数、Shannon's信息指数分别为0.3636、0.2466、0.2460、0.3677,说明野生锥栗居群具有较高的遗传多样性和变异度。其中,衡山(HS)居群的多态性位点百分率最高,为85.07%,吉首小溪村(JS)居群次之,为83.26%,表明衡山、湘西一带为湖南省野生锥栗居群遗传多样性最丰富的区域。UPGMA聚类分析表明,浏阳溪江居群和衡山居群间的遗传相似性最大,亲缘关系最近;贵州黎平居群和岳阳月田镇居群间的遗传相似性最小,遗传差异较大。23个锥栗品种多态性位点百分率占比为89.14%,遗传相似性系数在0.66~0.85之间,且在遗传相似性系数0.66处,大尖嘴单独聚为一类,反映出它的遗传基础与其他品种具有较大的差异;在遗传相似性系数0.85处,华栗2号和铁锥被聚为一类,表明这2个品种亲缘关系最近,遗传差异最小。此外,还构建了Em1-Me2、Em2-Me1、Em2-Me2和Em2-Me3共4个引物组合的SRAP数字指纹图谱,为锥栗品种的快速鉴定提供了参考依据。     

大盘山自然保护区香果树群落结构特征

对浙江省大盘山国家级自然保护区香果树群落结构特征以及香果树种群结构进行了调查研究。研究表明,香果树主要伴生种为具有热带性质的樟科和山茶科的一些物种;该群落乔木层、灌木层、草本层的物种丰富度、多样性、均匀度都偏低,优势度相对较高;其生活型以包括藤本在内的高位芽植物占绝对优势,达75.90%;叶级以中型叶为主,占53.97%,小型叶次之,占36.51%;叶型以单叶占有较大的优势,达74.70%;叶质以纸质叶为主,占63.86%。香果树在群落水平结构上整体成聚集分布状态,垂直结构上明显分成3个亚层;种群更新不良,具有明显的衰退趋势。     

Pollination of Schisandra henryi (Schisandraceae) by female, pollen-eating Megommata species (Cecidomyiidae, Diptera) in south-central China

BACKGROUND AND AIMS: The mutualistic interaction between insects and flowers is considered to be a major factor in the early evolution of flowering plants. The Schisandraceae were, until now, the only family in the ANITA group lacking information on pollination biology in natural ecosystems. Thus, the objective of this research was to document the pollination biology and breeding system of Schisandra henryi. METHODS: Field observations were conducted in three populations of S. henryi and the floral phenology, floral characters and insect activities were recorded. Floral fragrances were sampled in the field and analysed using TCT-GC-MS. Floral thermogenesis was measured with a TR-71U Thermo Recorder. Pollen loads and location of pollen grains on insect bodies (including the gut) were checked with a scanning electron microscope and under a light microscope. KEY RESULTS: Schisandra henryi is strictly dioecious. Male flowers are similar to female flowers in colour, shape, and size, but more abundant than female flowers. The distance between tepals and the androecium or gynoecium is narrow. Neither male nor female flowers are fragrant or thermogenic. Schisandra henryi is pollinated only by adult female Megommata sp. (Cecidomyiidae, Diptera) that eat the pollen grains as extra nutrition for ovary maturation and ovipositing. Both male and female flowers attract the pollinators using similar visual cues and thus the female flowers use deceit as they offer no food. CONCLUSIONS: Schisandra henryi exhibits a specialized pollination system, which differs from the generalized pollination system documented in other ANITA members. Pollen is the sole food resource for Megommata sp. and the female flowers of S. henryi attract pollinators by deceit. This is the first report of predacious gall midges utilizing pollen grains as a food source. The lack of floral thermogenesis and floral odours further enforces the visual cues by reducing attractants for other potential pollinators.     

栗属中国特有种居群的遗传多样性及地域差异

采用超薄平板聚丙烯酰胺等电聚焦技术对栗属（Ｃａｓｔａｎｅａ（Ｔｏｕｒｎ．）Ｌ．）３个中国特有种即中国板栗（Ｃ．ｍｏｌｉｓｉｍａＢＬ．）、茅栗（Ｃ．ｓｅｇｕｉｎｉＤｏｄｅ．）和锥栗（Ｃ．ｈｅｎｒｙｉ（Ｓｋａｎ）Ｒｅｈｄ．ｅｔＷｉｌｓ．）的３０个居群,１２个酶系统的２０个位点进行了遗传多样性与遗传结构分析。结果表明：中国板栗在种和居群水平都具有较茅栗、锥栗高的遗传多样性（Ｐ分别为９０．０％和８４．７％,Ｈｅ分别为０．３１１和０．２９５）,尤以长江流域居群表现显著,揭示了长江流域的神农架及周边地区为中国板栗的遗传多样性中心。Ｎｅｉ的遗传一致度测量结果显示中国板栗和茅栗的亲缘关系最近,并且地理距离和遗传距离有一定的相关性。中国板栗、茅栗和锥栗的遗传分化程度逐渐增大,Ｇｓｔ分别为７．５％、１０．９％和２２．１％;基因流（Ｎｍ）分别为３．２０、２．０５和０．８８。研究结果为探明栗属起源、系统进化及制定保育策略提供了科学依据。     

大盘山自然保护区香果树种群结构与分布格局

在大盘山自然保护区设置了4个有代表性的样地,应用相邻格子法进行调查获得野外资料。对香果树种群进行统计,绘制径级结构图和高度结构图、编制种群的特定时间生命表;应用理论分布模型和聚集强度指数进行种群分布格局分析。结果表明：香果树种群结构呈纺锤型,幼苗严重不足,种群有衰退的趋势;其更新是以无性繁殖为主;种群格局整体上呈集群分布,但在不同发育阶段,分布格局有所差异：幼树阶段一般为集群分布,中树和大树向随机分布发展,这种分布格局变化与其生物学和生态学特性密切相关;其格局规模在介于8S和32S之间。分析认为,香果树的种群结构和分布格局受到了多种因素的影响,如群落区域小生境、香果树生物学特征以及人为干扰外等,在以上各因素的综合作用下,使得该种群形成典型的小种群。     

大盘山香果树(Emmenopterys henryi)种内及其与常见伴生种之间的竞争关系

应用了生态位和单木竞争模型对浙江省大盘山国家级自然保护区香果树(Emmenopterys henryi)种内及其与常见伴生种之间的竞争关系进行了研究.结果表明,群落中,香果树的生态位宽度最大,香果树与其伴生种生态位的重叠值顺序为:杉木 > 红脉钓樟 > 山胡椒 > 七子花 > 尖连蕊茶;对生境的要求非常相近的山胡椒、红脉钓樟和尖连蕊茶之间,其生态位重叠值极高.采用Hegyi单木竞争模型的研究结果表明,在早期阶段,香果树的种内竞争强度随着径级的增加而增大,胸径大于15 cm后,其竞争强度又逐渐降低.种间竞争强度的大小顺序为:香果树 > 杉木 > 七子花 > 红脉钓樟 > 山胡椒 > 尖连蕊茶.两种方法的研究结果表现出较高的一致性,如种内竞争大于种间竞争;种间竞争又以香果树-杉木之间的竞争最大,而香果树-尖连蕊茶之间竞争最小,且两种方法的结果具有一定的互补性.因此,建议在对群落竞争关系的研究中,将生态位和单木竞争模型相结合,更能客观的反映其竞争关系.另外,在经营香果树人工林时,为了给香果树创造一个良好的生存环境,应选择灌木树种作为其主要的伴生种而不宜选择生长迅速的常绿树种.     

栗属中国特有种居群的遗传多样性及地域差异

Genetic variability in 30 populations of three endemic Castanea (Tourn.) L. species (C. moUissima BI., C. seguinii Dode. and C. henryi (Skan) Rehd. et Wils. ) in China was investigated using isoelectric focusing in thin-layer polyacrylamide slab gels at 20 loci coding for 12 enzyme systems. C. mollissima was found to possess a significant higher value of genetic variability than that of the other two species. The percentage of polymorphic loci (P) and the expected heterozygosity (He) were 90.0% and 0. 311 at the species level, respectively; while P = 84.7 %, He = 0.295 at the population level. Comparison of the population genetic variability of C. mollissima in three regions of China, the populations from the Yangtze River valley showed a markedly higher mean expected gene heterozygosity. The results provided additional evidence that the Yangtze River valley, particularly in Shennongjia area, was the center of the genetic diversity of C. moUissima. Genetic relationships among populations and species were assessed by Nei genetic identity (I) and standard genetic distance (D), suggesting that C. mollissima and C. seguinii have a closer relationship, and genetic distances were correlated with geographical distances among populations. Genetic differentiation between populations in C. mollissima, C. seguinii and C. henryi was 7.5%, 10.9% and 22.1%, respectively, and the gene flow rate (Nm) was 3.20, 2.05 and 0.88 respectively. The study provides useful imfonnation for understanding of the origin and evolutionary events in genus Castanea and planning an effective conservation strategy.     

锥栗不同造林密度试验

在福建建瓯锥栗主产区进行锥栗不同造林密度试验,结果表明,锥栗栽培最佳密度为4m×5m或5m×5m,既充分利用林地,又有利于锥栗结实,最大限度地发挥林地的生产力,达到高产、稳产。     

Studies on Chemical Constituents of Emmenopterys henrys Oliv. Native to China

Emmenopterys henryi Oliv. is native to China. Only one species is involved in this genus Emmenopterys. This species is distributed in the western part and southern part of China. No datum of chemical constituents on Emmenopterys henryi has been recorded. Nine crystalline substances have been isolated from ether and ethanol extractions of trunk of E. henryi. Eight of them have been identified as taraxerone, taraxerol, ursolic acid acetate, β-sitosterol, scopoletin, umbelliferone, daucosterol, and umbelliferone-7-β-D-glucoside, respectively, by chemical and spectral (IR, UV, NMR, and MS) analysis.