生物多样性保护优先区对重庆苔藓植物多样性保护的重要性

生物多样性保护优先区的生物多样性十分丰富, 对于生物多样性保护具有重要意义。本文基于野外调查数据和文献资料, 整合大巴山和武陵山两个中国生物多样性保护优先区重庆境内的苔藓植物名录, 通过分析物种丰富度、中国特有种和受威胁物种, 比较了这两个地区的苔藓植物组成特点和相似性。结果显示, 两个保护优先区重庆境内共有苔藓植物77科221属722种, 其物种数分别占重庆市和中国苔藓植物总种数的76.0%和23.9%。两个区域分布有中国特有苔藓植物56种, 占中国苔藓植物总种数的1.9%; 分布有极危苔藓植物1种、濒危4种和易危3种。科、属、种的Jaccard相似性系数分别为0.7、0.6和0.3, 表明两个区域物种组成差异较大。大巴山和武陵山两个中国生物多样性保护优先区都具有较高的苔藓植物物种多样性, 其种类组成具有一定代表性, 对重庆市和中国苔藓植物多样性保护具有重要价值。     

浙江西天目山30年来苔藓物种多样性变化

苔藓物种多样性变化对苔藓植物保护和森林生态系统健康起着重要的预警作用.基于1977-1980年和2010-2011年对西天目山国家自然保护区苔藓植物的两次详细调查,本文比较了该地区1977-2011年间苔藓植物物种多样性的变化.结果表明:(1)在过去的30年间,该地区苔藓植物的科、属、种数均呈下降趋势,苔类植物的属、种数减少尤为显著;(2)青藓科、曲尾藓科、灰藓科和丛藓科一直为该地区的优势科;(3)科的稳定性均高于属、种;(4)缓冲区的总物种数变化最大,新增物种数最多;核心区(进山门-老殿)苔藓植物种类始终最为丰富,两个时期的物种相似性最高,且苔类占新增物种数百分比最高;核心区(老殿-仙人顶)苔藓物种数最少,相似性最低;(5)核心区的物种多样性要高于缓冲区,是该地区保护苔藓植物多样性的关键区域.     

安徽省苔藓植物名录

物种名录是一个地区生物多样性的本底性资料, 及时更新生物物种名录对生物多样性的保护及促进基础数据共享都具有重要意义。为了及时总结安徽省苔藓植物的分类学研究成果, 本文通过对文献的收集和分析, 整理出安徽省苔藓植物名录。结果显示, 安徽省共有苔藓植物95科253属777种, 其中角苔类3科3属3种, 苔类36科62属185种, 藓类56科188属589种。种数多于25的科为青藓科、细鳞苔科、丛藓科、真藓科、灰藓科、提灯藓科、白发藓科、绢藓科和蔓藓科。种数多于15的属为青藓属(Brachythecium)、真藓属(Bryum)、绢藓属(Entodon)、光萼苔属(Porella)、羽苔属(Plagiochila)、灰藓属(Hypnum)、凤尾藓属(Fissidens)、棉藓属(Plagiothecium)和耳叶苔属(Frullania)。区系成分组成上, 安徽苔藓植物以东亚成分占优势, 达到44.40%, 温带成分占31.53% (其中以北温带型最多, 占25.61%), 热带成分占18.92% (其中以热带亚洲成分最多, 达到10.30%)。安徽省共有中国特有苔藓55种, 濒危种1个, 易危种8个。安徽苔藓植物调查呈现出地区不均衡性, 建议在广泛调查的同时加强名录修订和专科专属研究, 对有条件的地区开展时空变化下物种多样性比较研究。     

浙江天目山国家级自然保护区苔藓植物多样性

苔藓植物因个体普遍细小,更易在野外观察及采集中被忽略,故很难获得一个客观、详尽的地区名录,导致对其多样性的研究和保护受到极大限制。本文以浙江天目山国家级自然保护区为例,采用区系生境调查法和样方法相结合的采样策略,沿海拔梯度对不同生境类型内苔藓植物多样性进行了系统调查,并结合多次历史普查资料整理出该保护区的苔藓植物名录。本研究共获得苔藓植物56科143属394种,包括苔类植物16科30属103种,藓类植物40科113属291种,其中有5种为濒危物种。与该保护区历史数据相比,本研究苔藓植物新增科4个、属31个、种182个,包括浙江省新记录科1个、属8个、种33个。区系生境调查法和样方法分别贡献了总物种数的81%和72%,但当调查范围只限定在树附生生境时,采用样方法所获得的总物种数及新增物种数均大于区系生境调查法。虽然代表更大采样努力程度的8个样方/树的调查获得的物种数显著高于2个样方/树的调查结果,但只针对树干0.3 m和1.5 m的2个样方/树的采样结果贡献了75%的物种数。鉴于本研究采集方法获得的较高苔藓植物物种丰富度及新增物种数以及物种组成在时间梯度上的巨大差异,建议在自然保护地开展...     

安徽石台县与青阳县苔藓植物多样性

生物多样性保护优先区域代表了生物多样性富集区、典型生态系统与关键物种分布区, 对于生物多样性保护具有重要意义, 但优先区域内自然保护地覆盖率通常较低, 存在很大的保护空缺。苔藓植物作为生物多样性的一个重要组成部分, 在生态系统中发挥着重要作用, 但由于个体细小、分类鉴定困难等, 使得其多样性保护成为整个生物多样性保护中较为薄弱的一环。为了了解我国生物多样性保护优先区域苔藓植物多样性及受保护情况, 本文以黄山-怀玉山生物多样性保护优先区域内的石台县和青阳县为例, 通过系统的样线法调查优先区域内自然保护地内、外的苔藓植物多样性, 比较了其物种组成特点及相似性。结果表明, 该区域共有苔藓植物64科140属344种, 包括苔类植物27科40属106种、藓类植物37科100属238种, 其中有5种为濒危物种。自然保护地内有60科120属270种, 保护地外有46科90属185种, 保护地内、外苔藓植物科、属、种的Jaccard相似性系数分别为0.66、0.50和0.32, 表明自然保护地内、外物种组成差异很大。与石台县和青阳县苔藓植物历史数据相比, 本研究新增苔藓植物14科64属273种, 其中包括安徽省新记录2科9属96种, 而且有18种仅分布于自然保护地外。根据对该区域物种累积曲线及外推估计分析, 当采集足够充分时, 基于标本数的物种多样性预测值为485种, 基于样线数的预测值为563种, 说明石台县和青阳县的苔藓植物多样性仍存在被低估的可能。本研究结果一方面表明了自然保护地之外的苔藓植物在保护中有重要价值, 另一方面也反映了苔藓植物的野外就地保护存在空缺。建议在我国其他生物多样性保护优先区域开展类似的调查和研究, 以期为今后对苔藓植物的分布规律及保护研究提供翔实的基础数据。     

祁连山不同景观类型中苔藓植物物种多样性研究

通过对祁连山不同景观类型中的苔藓植物进行样方调查与物种组成统计,采用物种相似性系数、多样性指数对苔藓植物物种多样性进行了分析。结果表明,30个10 m×10 m的样地内共计苔藓植物19科34属48种,其中优势科(≥3种)有6科,含19属31种,分别占本地区苔藓植物总属数和总种数的55.88%和64.58%。在5种景观类型中,针叶林带和高山灌丛带分布的苔藓植物物种相似性最高(相似性系数为0.5357);河岸带和高山草甸带分布的苔藓植物物种相似性最低(为0),表现出祁连山地区苔藓植物分布的丰富性和复杂性;高山灌丛带分布的苔藓植物物种多样性指数最高,但针叶林带苔藓植物最为丰富,是祁连山苔藓物种多样性保护的关键区域。     

中国苔藓植物多样性研究进展

苔藓植物是生物多样性的重要组成部分, 包括角苔植物、苔类植物和藓类植物三大类群, 其物种数量仅次于被子植物, 是高等植物的第二大类群。我国是世界苔藓植物多样性最丰富的国家。自2017年以来, 我国苔藓学者在世界范围发现了10个新属, 40个新种, 建立了新的地钱纲分类系统; 更新了我国苔藓植物物种名录, 完成了数本分类学专著, 并在苔藓系统发育基因组、苔藓植物多样性与环境关系、苔藓植物多样性保护等领域取得了可喜的进展。对未来的研究, 我们提出5点建议: (1)加强对重要生态系统、国家公园和关键类群的物种多样性调查; (2)加快基于基因组的苔藓植物多样性研究; (3)加强苔藓植物保护研究; (4)加强西北地区苔藓植物多样性研究人才的培养; (5)进一步加强国际合作, 努力构建“一带一路”国家苔藓植物多样性平台。     

海南岛苔藓植物研究历史、现状与展望

综述了海南岛苔藓植物的研究历史和现状。目前海南岛已记录的苔藓植物共有87科227属806种,其中苔类33科71属366种,藓类51科152属436种,角苔类3科4属4种;苔藓植物的区系组成以热带亚洲成分为主,与香港、台湾地区的种属相似性高;对海南岛苔藓植物的研究集中在尖峰岭、霸王岭、吊罗山3个国家级自然保护区;叶附生苔是海南热带雨林主要的苔藓生态分布类型之一,共有7科23属123种;初步统计濒危苔藓植物有15种。今后应继续开展广泛和持续的物种多样性调查,从生态学、植物化学、分子生物学等领域进行研究,促进合理的开发利用和推动保护工作。     

喀斯特石漠化区苔藓植物物种多样性变化

为了揭示喀斯特石漠化地区苔藓植物的物种多样性,通过野外实地调查对贵州喀斯特地区不同程度石漠化区域苔藓植物进行研究。结果表明,苔藓的科、属、种数量随着石漠化程度加剧而下降,其中,强度石漠化的科数最少且显著低于其他三种石漠化类型,比潜在、轻度、中度石漠化地区苔藓科数分别降低70.00%、57.14%、33.33%;轻度石漠化地区的真藓科、青藓科、丛藓科、曲尾藓科等包含属数较多,占总属数34.62%;Shannon-Wiener指数和Simpson指数变化基本一致,随石漠化程度加剧而下降,其中苔藓植物在潜在石漠化地区Shannon-Wiener指数为1.9393,高于其他三种石漠化区域,比强度石漠化区高43.97%,Simpson指数以轻度石漠化过渡到中度石漠化地区物种丰富度下降最快,下降26.73%;潜在石漠化区较其他三个区域拥有更高的苔藓数量。说明苔藓植物的分布和石漠化程度密切相关,随着石漠化程度加重,苔藓植物的科、属、种总数均有不同程度下降。     

上海城市公园苔藓植物多样性分布格局及其环境影响因子

城市公园的生物多样性十分丰富,在生物多样性保护方面具有重要价值。苔藓植物是公园生物多样性的重要组成成分,但因其体型小、难以鉴定等,容易被人们所忽略,因此对其多样性的研究和保护也相对薄弱。本文基于文献资料和生态调查数据,整合上海市中心城区和郊区共35个样点的苔藓植物名录,应用聚类分析对公园进行分组,比较了市区和郊区两个区域的苔藓植物相似性;采用典范对应分析(CCA)及层次分割的方法,定量研究环境因子与城市公园苔藓植物多样性分布格局的关系。结果表明, 35个公园共有苔藓植物34科74属164种,包括苔类7科8属9种、藓类27科66属155种,其中有12种中国特有种和4种近危种。根据聚类分析结果, 35个公园可划分为两组,主要与人口密度、与市中心距离、与主干道距离及公园面积等因素有关。市区和郊区两个区域的科、属、种的Jaccard相似性系数分别为0.94、0.89和0.30,表明两个区域的物种组成各有特点。层次分割结果显示,环境因子对城市公园苔藓植物多样性分布格局的解释率从高到低分别为人口密度、公园年龄、与市中心距离、与主干道距离、森林覆盖率、湖泊覆盖率及公园面积。整体上,上海城市公园苔藓植...     

略论棕榈科与新分出的省藤科的系统分类、演化、区系地理及主要的经济用途

棕榈科原省藤亚科因其子房壁及外果皮被倒生、螺旋状排列的鳞片所覆盖,而区别于其他亚科,因而独立分出成一新科--省藤科。作者讨论了棕榈科的祖先种可能在石炭纪时,自原始裸子植物开以顿目在分化、衍生出苏铁目祖先种的进化干上,于白垩纪时分化出的一个分支。在棕榈科的祖先种出现不久后,在其进化的分支上,于白垩纪后期又分化出一旁支,成为棕榈科的姊妹科--省藤科的祖先种。从两祖先种分别再分化、衍生出现今分布地球上该二科的属与种。两科、尤其前者是被子植物、尤其是单子叶植物中最原始的类群之一。作者还提出棕榈科象牙椰亚科与贝叶棕亚科是该科最原始或较原始的两类群;槟榔亚科和腊材榈亚科是较进化的两类群;而水椰亚科祖先种可能源于象牙椰亚科的祖先种,但又演化为该科最进化与特化的类群。省藤科省藤亚科略比鳞果榈亚科原始。作者讨论了两科为泛热带分布的科,指出两科的"现代分布区"在南北两半球热带地区,少数种还延伸分布到两半球暖亚热带、甚至达中亚热带地区,分布区边缘最北达日本中部、中国长江流域及黄河下游的南部,美国加利佛尼亚州与佛罗里达州和地中海北部;最南达智利中部和新西兰南部;而"现代分布中心"在热带与暖亚热带的亚洲,中、南美洲,大洋洲及非洲的东、南、西部;但分布区的"密集中心"则在热带亚洲、热带中及南美洲、南太平洋群岛及非洲东南部。作者还介绍了近50年我国南方引种驯化成功的两科植物近400种(见^*图谱),其中少数为耐寒的种类,有的种已引种到长江流域或更北的地区。引种的大部分种都有其重要的经济用途,包括:1. 食用,如淀粉和树液可制"西米"或制糖,酿酒、醋或作饮料;果或种子榨油,供食用或工业用;某些种的嫩芽作蔬菜,甚至种子代咖啡饮用;2. 药用,有消炎、止血、活血、驱虫、抗癌等用;3. 建筑、工艺与日用品,包括不少种的树干供建普通房子、桥梁、小船;少数种可提制工业用蜡;许多种的纤维制高级缆绳和编织品;还制工艺品与日用品等;4. 代表热带景观的园林工程、绿化及美化环境的观赏树和人行道树及建造园林景观生态类型的树种等。     

Taxonomy of the Genus Oreocharis (Gesneriaceae)

The genus Oreocharis as circumscribed here consists of 27 species including 5 varieties, of which 5 species and 4 varieties are described as new in the present paper. In the work analysed were the external morphology and geographic distribution and examined under SEM were pollen exine of 22 species and seed coat of 16 species. As a result, three types of the corolla, two types of the anther, three types of the pollen exine and three types of the seed coat are distinguished here in the paper. It is discovered that the corolla in the genus is relatively stable, though diverse, and highly correlated with the characters of pollen grains and seeds. The corolla clearly bilabiate but constricted at the throat, occurring in O. auricula, O. cordatula, O. aurantiaca, etc., for an example, is correlated with smooth, reticulate pollen exine and partial tectum and the reticulate and smooth seed coat. For this reason the subdivision of the genus in the paper is mainly based on the characters of the corolla, but combined with those of the anther, pollen and seed coat. The genus is divided into four sections in the present classification. Dasydesmus Craib, based on a single species. O. bodinieri, is reduced here, and the reasons are given. The genus is distributed mainly in the subtropics, and less frequently in the tropics, of China south of 32.5°N and east of 98.5°E, with only two species beyond the border, O. hirsuta in Thailand (only a single locality in Chiengmai) and O. aurea also found in north Vietnam (see Fig. 1, Table 3). Sect. 1. Stomactin (Clarke) Fritsch. Corolla urceolate-tubular, constricted at the throat, with limb distinctly bilabiate; anthers broad-oblong; seed coat reticulate, smooth, rarely minutely tuberculate; pollen exine fine-reticulate, tectum partial and smooth, luminae slightly unequal in size. Sect. 2. Orthanthera K. Y. Pan Corolla campanulate or campanulate-tubular; anthers broad-oblong; seed coat reticulate, muri smooth, rarely spiny-processed; pollen exine fine-reticulate, with partial and smooth tectum and luminae slightly unequal in size, rarely exine insular and fine-tuberculate, tectum perforate. Setc. 3. Oreocharis Corolla thin-tubular; anthers broad-oblong; seed coat densely spinyprocessed, rarely fine-tuberculate; pollen exine insular, densely spiny-processed, rarely finereticulate and smooth, luminae unequal in size. Sect. 4. Platyanthera K. Y. Pan Corolla campanulate; anthers hippocrepiform; seed coat densely spiny-processed; pollen exine fine-reticulate, tectum perforate, luminae small, nearly equal in size. In the section Stomactin, although the constriction of corolla at its throat is a specialized character, the characters of seed coat, pollen grains and anthers are apparently primitive. Therefore it may be said at least that more primitive characters are preserved in the section. In the section Oreocharis, on the contrary, the characters of corolla, seed coat and pollen exine are all advanced. And in the section Platyanthera, the seed coat, pollen (with perforate tectum) and anthers have developed rather specialized characters.     

Effects of Microbial and Other Antagonistic Organism and Competition on Entomopathogenic Nematodes

Antagonistic factors, broadly identified as antibiosis, competition and natural enemies, impact on entomopathogenic nematodes. Antibiosis can occur through the release of plant chemicals from the roots into the soil, which may adversely affect the host-finding behavior of the infective stage nematode, or the presence of these chemicals in the host insect may negatively affect nematode reproduction. In laboratory studies, intra-specific and inter-specific competition reduces nematode fitness, and inter-specific competition can cause local extinction of a nematode species. For example, after concomitant infection of a host, a steinernematid species usually excludes a heterorhabditid species. The mechanism for the steinernematid superiority has been postulated to be a bacteriocin(s) produced by Xenorhabdus, the symbiotic bacterium of the steinernematid, which prevents Photorhabdus, the symbiotic bacterium of the heterorhabditid, from multiplying. Inter-specific competition between two steinernematid species shows that both can co-exist in a host, but one species will eventually prevail in the environment. By having different foraging strategies, however, both steinermatid species may co-exist in the same habitat. An important issue is whether the introduction of an exotic entomopathogenic nematode species will competitively displace an indigenous nematode species. Although the environmental risks are small, the recommended policy is that the introduction of exotic nematodes be regulated. With other pathogens, entomopathogenic nematodes can out-compete entomopathogenic fungi, but not Bacillus thuringiensis, for the same host individual when both the nematode and entomopathogen are applied simultaneously. The best studied natural enemy is the nematophagous fungus, Hirsutella rhossiliensis, which causes higher mortality in Steinernema glaseri compared with Heterorhabditis bacteriorphora. Differential susceptibility to the fungus may be associated with the retention of the second-stage cuticle by H. bacteriophora. Invertebrate predators including mites and collembolans feed on entomopathogenic nematodes. Although a number of studies have been conducted with antagonists, there is a dearth of field data. We suggest that long-term research plots be established where natural populations of entomopathogenic nematodes occur and include antagonists as a component of such studies.     

山东山旺Palaeomeryx化石的初步研究

Palaeomeryx 在含义、性质和分类位置上,一直是一个争论较多的属.最近在山旺发现的 Palaeomeryx 完整骨架,为解决上述问题提供了有价值的资料和证据. Palaeomeryx 雄性具有一对眶上"皮骨角"和单一的"枕顶角".根据共近裔性状的分析,本文作者认为 Palaeomeryx 应该归入长颈鹿,作为这一支中最早分出的一个旁支.长颈鹿和鹿科有较近的亲缘关系,而和牛科的关系较远. Palaeomeryx 大概位于 Blastomeryx 和 Leptomeryx 之间,从反刍类主干中分出.山旺的材料,代表本属中一个较原始的新种: Palaeomeryx tricornis. 它的时代,可能相当于欧洲的 MN4 或 MN5.     

Phylogenetic analysis of the Brachyura (Crustacea, Decapoda) based on characters of the foregut with establishment of a new taxon

The Brachyura, within the decapod crustaceans, is one of the most species-rich taxa with up to 10 000 species. However, its phylogenetic history, evolution and fossil record remain subjects of controversy. In our study, we examined the phylogenetic relationships of the Brachyura based on morphological characters of the foregut. The cladistic analysis supports a monophyletic Brachyura including the Dromiidae and Raninidae. A clade comprising Dromiidae and Dynomenidae forms the most basal assemblage within the Brachyura, followed by the Homolidae and Latreilliidae. As a result, neither Podotremata nor Archaeobrachyura form a clade. In contrast, foregut data suggest that the classical taxon Oxystomata, comprising Calappidae, Parthenopidae, Dorippidae, Leucosiidae, Cymonomidae and Raninidae, is monophyletic. This makes the Heterotremata paraphyletic or polyphyletic. A newly established taxon, Neobrachyura, embraces some representatives of the Heterotremata and the monophyletic Thoracotremata.     

Notulae de Ranunculaceis sinensibus (ⅩⅩⅢ)

(1) In this paper, differences among the five genera constituting the tribe Cimi cifugeae of the family Ranunculaceae are discussed. Beesia, the first genus, with compound cymes and flowers bearing neither petals nor staminodes, is different from the other four genera with simple or compound racemes and flowers bearing either petals or staminodes, and may occupy a primitive position within the tribe. As to the other four genera, Souliea is characterized by the stem without basal leaf but with 2～5 sheath-like cataphylls, the sepals being deciduous but not caducous, moderate in size and petaloid, the petals being much smaller than sepals, but pink in color and more or less petaloid, the pollen grains being pan tocolpate or pantoporate, the carpels being 1～3 per flower, when mature forming dry linear follicles conspicuously reticulate on the surface and dehiscent along the ventral suture, and the seeds being reticulate-foveolate on the surface. These diagnostic characters indicate clear ly that Souliea might have deviated from the lineage formed by the next three genera, i. e. Anemopsis, Cimicifuga, and Actaea, which have their own well-recognizable diagnostic characters. Anemopsis is characterized by the normally developed basal leaf, the racemose inflorescence with sparse and few long pedicellate flowers, the sepals 7～10 in number, mod erate in size, and petaloid, the petals slightly smaller than sepals, the tricolpate pollen grains, the carpels 2～4 per flower, stalked, when mature forming dry oblong follicles with transverse veins on the surface, and the seeds with scaly membranous wings. Cimicifuga is distinguished by the normally developed basal leaf, the caducous, small, often sepaloid sepa ls, the organs of the second floral whorl sometimes with empty sterile anthers being stamin odes not petals, the tricolpate pollen grains, the carpels 1～8 per flower, when mature form ing dry oblong or ovoid follicles with transverse veins on the surface, and the seeds usually with scaly membranous wings. The last genus Actaea is different by the basal leaf trans formed into a small scale, the caducous, small, often sepaloid sepals, the organs of the sec ond floral whorl being clawed petals, the pollen grains with 3(4～6) colpi, carpel 1 per flow er, when mature forming a fleshy indehiscent berry smooth on the surface and without any veins, the seeds roughish or slightly rugose, neither foveolate nor winged on the surface, and the advanced most asymmetric karyotype. According to the diagnostic characters given above, we believe that Beesia, Souliea, Anemopsis, Cimicifuga, and Actaea do represent five independent genera, and the treatment of the tribe Cimicifugeae including these five genera in it by Hutchinson (1923), Janchen (1949) and some other authors, has precisely shown the taxonomic diversity within the tribe. We are therefore unable to accept the treatment published by Compton et al. (1998) to lump the two genera, Souliea and Cimicifuga, into the genus Actaea. (2) Compton et al. (1998, 1997) found out that the Chinese plants previously identified by various authors as Cimicifuga foetida L., in which the terminal and lateral racemes of the compound raceme flower more or less simultaneously, differ from the true C. foetida L. in northern Asia, in which the terminal raceme of the compound raceme flowers before the lateral ones, and thus restored the species name Cimicifuga mairei Lévl. , which was formerly reduced to the synonymy of C. foetida L. , for the Chinese plants. After examining the specimens collected from Siberia and from Southwest China we failed to find out any other differences in both vegetative and reproductive organs between the plants of the two regions, and we consider that it is better to treat the populations in Southwest and Central China as a geographical variety of Cimicifuga foetida L. A new combination, Cimicifuga foetida L. var. mairei (Lévl.) W. T. Wang & Zh. Wang, is thus made. (3) 3 species of Delphinium, 1 species and 1 variety of Clematis are described as new.     

Epididymal compounds and their influence on the metabolism and survival of spermatozoa

Epididymal fluid, which is derived from testicular fluid, contains several unusual compounds. Little information is available on the composition of the testicular fluid of primates, but the fluid of the ram, bull, boar, and rat contains high concentrations of inositol and certain amino acids. Analyses have been made of epididymal fluid collected from the cauda epididymis of the Rhesus monkey and several nonprimate species (e.g., ram, bull, dog, stallion, rabbit, guinea pig, rat, and hamster), but similar information on the human is lacking. Cauda epididymal fluid appears to be similar in composition from one mammalian species to another. However, the epididymal plasma differs considerably from blood, lymph, and other extracellular fluids. The environment of spermatozoa in the epididymis is, therefore, highly specialized, and presumably in some way contributes to the prolonged survival of spermatozoa in this organ, and provides substrates for the metabolism of the spermatozoa. The chief characteristics of the cauda epididymal plasma are the low concentration of inorganic ions and the high levels of several unusual organic constituents namely, glycerylphosphorylcholine, carnitine, sialic acid, amino acids, glycosidases, and phosphatases. At least one antifertility compound, namely, orally administered α-chlorohydrin, appears to be concentrated in the epididymis. Studies on laboratory animals, domestic species, and man, suggest that it inhibits enzymes of the glycyolytic pathway in spermatozoa, and this may be the basis for its antifertility activity.     

Floral elaiophore structure in four representatives of the Ornithocephalus clade (Orchidaceae: Oncidiinae)

Background and Aims A significant number of species assigned to the Neotropical orchid sub-tribe Oncidiinae reward insect pollinators with oil produced in floral glands termed elaiophores. The latter may be glabrous (epithelial elaiophores) or hirsute (trichomal elaiophores). Although the detailed anatomy and ultrastructure of epithelial elaiophores have been studied for a number of genera, such as Oncidium Sw., Gomesa R. Br. and Trichocentrum Poepp. & Endl., hitherto, trichomal elaiophores have been investigated only for a single species of Oncidiinae, Ornithocephalus ciliatus Lindl. Furthermore, this is the only representative of the Ornithocephalus clade to be investigated to date. Here, an examination is made of the elaiophore anatomy and ultrastructure of a further four species currently assigned to this clade (Ornithocephalus gladiatus Hook., Phymatidium falcifolium Lindl., Zygostates grandiflora (Lindl.) Mansf. and Zygostates lunata Lindl.) and the results compared with those obtained for other Oncidiinae. Methods Elaiophore structure was examined for all species at three stages of flower development: closed bud, first day of anthesis and final stage of anthesis, using light microscopy, fluorescence microscopy, scanning electron microscopy, transmission electron microscopy and histochemistry. Key Results Elaiophores of O. gladiatus occur upon the lateral lobes of the labellum and display characters intermediate between those of typical epithelial and trichomal elaiophores, in that they are largely glabrous, consisting mainly of cuboidal epidermal cells, but bear short, unicellular hairs proximally. By contrast, the elaiophores of all the other species investigated occur on the callus and are of the trichomal type. In P. falcifolium, these unicellular hairs are capitate. In all species, oil secretion commenced at the closed floral bud stage. Ultrastructurally, the mainly trichomal elaiophores of the four representatives of the Ornithocephalus clade closely resembled the epithelial elaiophores of other Oncidiinae, in that their cells displayed an organelle complement typical of lipid-secreting cells. However, in some taxa, a number of noteworthy characters were present. For example, the elaiophore cuticle of O. gladiatus and P. falcifolium was bi-layered, the outer layer being lamellate, the inner reticulate. The cuticle of Z. grandiflora and Z. lunata was also lamellate, but here, a reticulate layer was absent. Accumulation of secreted oil resulted in the localized distension of the cuticle. Cuticular cracks and pores, however, were absent from all species. The walls of the secretory cells of Z. grandiflora were also atypical in that they had short protuberances or ingrowths, and contained cavities which are thought to be involved in the secretory process. Conclusions Of the species investigated, most displayed similar anatomical organization, their trichomal elaiophores occurring on the labellar callus. They, thus, differ from many other members of the Oncidiinae, where epithelial elaiophores are found either on the callus, or on the lateral lobes of the labellum. However, ultrastructurally, all elaiophores, whether those of representatives of the Ornithocephalus clade, or those of other oil-secreting Oncidiinae, possessed a similar complement of organelles, regardless of whether the elaiophores were trichomal or epithelial. In view of the latter, and the similar chemical composition of oils derived from all Oncidiinae investigated to date, it is probable that position and type of elaiophore, and possibly the structure of the overlying cuticle, play an important role in pollinator selection in these oil-secreting orchids.     

Tissue specific protochlorophyll(ide) forms in dark-forced shoots of grapevine (<Emphasis Type="Italic">Vitis vinifera</Emphasis>L.)

Cuttings of grapevine (Vitis vinifera L. cv. Chardonnay) were dark-forced at least three weeks. Pigment contents, 77 K fluorescence emission, excitation spectra of the leaves, petioles, stems, transmission electron micrographs of the etioplasts from leaves, the chlorenchyma tissues of the stems were analysed. The dark-grown leaves, stems contained 8 to 10, 3 to 5 μg/g fresh weight protochlorophyllide, its esters, respectively. HPLC analysis showed that the molar ratio of the unesterified, esterified pigments was 7:3 in the shoot developed in darkness. The dark-forced leaves contained carotenoids identified as: neoxanthin, violaxanthin, antheraxanthin, lutein, β-carotene. Detailed analyses of the fluorescence spectra proved that all tissues of the dark-forced shoots had protochlorophyllide or protochlorophyll forms with emission maxima at 628, 636, 644, 655, 669 nm. The 628, 636 nm emitting forms were present in all parts of the dark-forced shoot, but dominated in the stems, which may indicate an organ specificity of the etioplast development. Variations in the distribution of the pigment forms were even found in the different tissues of the stem. The subepidermal layers were more abundant in the 655 nm form than the parenchyma cells of the inner part of the cortex, the pith. In the latter cells, the plastid differentiation stopped in intermediary stages between proplastids, etioplasts. The plastids in the subepidermal layers had developed prolamellar body structures, which were similar to those of etiolated leaves. The results highlight the importance of organ-, tissue specificity of plastid differentiation for chlorophyll biosynthesis, greening of different plant organs. This revised version was published online in June 2006 with corrections to the Cover Date.