鳞毛蕨科3种植物配子体发育的研究

利用光学显微镜详细观察鳞毛蕨科(Dryopteridaceae)3属3种植物,即耳蕨属的棕鳞耳蕨(Polystichum polyblepharum)、鳞毛蕨属的黑足鳞毛蕨(Dryopteris fuscipes)和鞭叶蕨属的鞭叶蕨(Cyrtomidictyum lepidocaulon)配子体发育过程,记录配子体各发育阶段的特征。结果表明:棕鳞耳蕨、黑足鳞毛蕨和鞭叶蕨的孢子都为单裂缝,孢子萌发类型为书带蕨型,配子体发育类型为三叉蕨型,性器官为薄囊蕨型,成熟原叶体为对称的心脏形,具毛状体;3属的属间差异包括孢子颜色、孢子纹饰、萌发时间、丝状体长度、片状体形状、毛状体和假根等特征,上述特征在属间存在交叉现象,因此,孢子形态和配子体发育特征不能作为区分耳蕨属、鳞毛蕨属和鞭叶蕨属的形态依据。     

膜叶铁角蕨属的形态系统学研究

膜叶铁角蕨属隶属于铁角蕨科,全世界约有30种,我国分布有18种,是该属植物的分布中心之一。到目前为止,膜叶铁角蕨属的物种数目和物种分类还存在很大争议,一些物种的界限和定义还模糊不清,为了得到一个自然的膜叶铁角蕨属分类系统,还需要对膜叶铁角蕨属的物种分类做进一步研究。该文在前人研究的基础上,对膜叶铁角蕨属10种植物的形态特征,包括孢子形态特征、叶柄和根状茎上的鳞片形态特征、叶片形态、羽片形状以及叶脉特征等进行详细观察分析,探讨了各个形态特征间的关系以及膜叶铁角蕨属植物的物种分类。结果表明:膜叶铁角蕨属植物的叶片及羽片等形态特征存在很大区别,叶柄和根状茎上的鳞片以及孢子形态的种间差异虽然不大,但其在大小、形状、颜色等方面的细微差别仍可作为部分种类的鉴定依据。该研究结果为膜叶铁角蕨属植物的物种分类及进一步研究提供了重要依据。     

七指蕨科和瓶尔小草科植物的叶表皮特征

在光学显微镜和扫描电子显微镜下,对七指蕨科和瓶尔小草科３个属３种代表植物的叶表皮内外面进行了观察。它们的表皮细胞形状较规则,垂周壁平直或略有弯曲,气孔器长轴与叶片长轴平行或近平行,保卫细胞下陷;但三属叶表皮在表皮细胞形状,     

鳞毛蕨科的孢子形态研究

对鳞毛蕨科及其相近类群的19属65种的孢子形态进行了光学显微镜观察,并对其中12属30种进行了扫描电镜观察。鳞毛蕨科的孢子左右对称,极面观为椭圆形、近球形,赤道观为肾形,极轴/赤道轴的比值为0.60～0.86;单缝孢,裂缝长度约为孢子全长的1/2～3/4,属中至大型孢子。鳞毛蕨科具有多样性的外壁纹饰:不仅包括刺状、瘤状、颗粒状、脊状、窗孔状、耳状、片状及翅状等几种基本类型,而且还存在一些中间过渡类型。根据孢子形态特征,对本科的属间关系进行了探讨。孢子形态特征的相似性支持假复叶耳蕨属、肉刺蕨属、球盖蕨科与鳞毛蕨属的近缘关系,黔蕨属与复叶耳蕨属间的近缘关系。玉龙蕨属的两个种的孢子纹饰与耳蕨属的部分种一致,支持将玉龙蕨属作为耳蕨属的异名处理。拟贯众属独特的翅状纹饰支持将其从鳞毛蕨科中分离出去。     

中国蕨类植物孢子形态的研究ⅩⅢ.叉蕨科

利用扫描电镜对中国产叉蕨科7属34种植物孢子的形态进行了观察。叉蕨科植物孢子为左右对称,极面观为椭圆形,赤道面观为半圆形、超半圆形或豆形;极轴长为18～38μm,赤道轴长为23～57μm;单裂缝,裂缝长度为孢子全长的1/2～2/3;孢子具脊状、翅状、刺状和耳状4种纹饰,孢子表面有时具细刺、颗粒或孔。通过孢粉学分析,叉蕨科依据孢子形态特征和依据孢子体形态特征的分类结果并不一致,孢粉纹饰类型呈现一定程度的属间交叉;支持将叉蕨科和鳞毛蕨科进行重新划分的MAARTEN J.M的新分类系统。     

广西蕨类植物孢子形态的研究Ⅲ.凤尾蕨科

利用光学显微镜和扫描电子显微镜对广西产凤尾蕨科及其近缘科蕨科、姬蕨科和碗蕨科5属9种植物的孢子形态进行了观察研究,详细描述了9种植物孢子的形态及表面纹饰特征.井栏边草、刺齿凤尾蕨、隆林凤尾蕨、剑叶凤尾蕨、林下凤尾蕨、蕨和碗蕨植物的孢子为三裂缝,辐射对称;极面观为钝三角形,赤道面观为半圆形或超半圆形;栗蕨和姬蕨植物孢子为...     

中国水蕨属孢子形态及其系统学意义的研究

利用扫描电镜和透射电镜技术对我国产水蕨属2种的孢子形态进行了观察,对2种的形态结构进行了描述。本属孢子是同型孢子蕨类植物中最大的孢子,三裂缝,肋状纹饰,由外壁形成纹饰的轮廓;具较薄的周壁,在高倍放大的情况下呈颗粒或杆状,我们从孢子形态角度,支持水蕨作为一个独立的科,它与海金沙科的非洲蕨属（Mohria)的亲缘关系较近,是介于海金沙科和裸子蕨科之间蕨群。     

不同蔗糟浓度对蕨精子器释放精子的影响

不同蔗糟浓度对蕨精子器释放精子的影响周云龙,方瑾,刘宁,陈令静（北京师范大学生物系,北京１００８７５）蕨（Ｐｔｅｒｉｄｉｕｍａｑｕｉｌｉｎｕｍｖａｒ．ｌａｔｉｕｓｃｕｌｕｍ）属蕨科,蕨属。从同一个培养瓶中取出用蔗时孢子培养的具成熟精子器的原叶体,将其...     

叉蕨科4属5种植物配子体的发育模式及其系统学意义

利用光学显微镜详细观察了叉蕨科（Aspidiaceae）4属5种植物,即肋毛蕨属（Ctenitis（C．Chr．）C．Chr．）的亮鳞肋毛蕨（C．subglandulosa（Hance）Ching）和海南肋毛蕨（C．decurrenti-pmnata（Ching）Ching）、轴脉蕨属（Ctenitopsis Ching ex Tard-Blot et C．Chr．）的轴脉蕨（C．sagenioides（Mett．）Ching）、黄腺羽蕨属（Pleocnemia Presl）的黄腺羽蕨（P．winitti Holtt．）以及叉蕨属（Tectaria Cav．）的剑叶叉蕨（T.leptophylla（C．H．Wright）Ching）的配子体发育过程,记录了配子体各发育阶段的模式特征,认为这5种植物的孢子、丝状体、片状体、生长点、翼片、细胞、毛状体和假根等具有稳定的系统学意义。检索结果与该科的经典分类结果基本相似,并在此基础上编写了各分类群的检索表。本研究为叉蕨科系统学研究积累了详实的配子体形态学资料。     

中国金毛裸蕨属植物孢子形态的研究

利用扫描电子显微镜对中国产5种金毛裸蕨属（QymnopterisBernb．）植物的孢子进行了观察,对每个种的孢子形态进行描述,并探讨与其它蕨类植物的关系,为本属植物的系统分类和孢粉学研究提供资料。     

Phylogenetic studies of Ophioglossaceae: evidence from rbcL and trnL-F plastid DNA sequences and morphology

Ophioglossaceae are a putatively ancient lineage of ferns in which the aerial portion of the plant is composed of a single leaf. The simplicity of foliar morphology has limited the number of characters available for constructing classifications and contributed to taxonomic difficulties at nearly every level of classification within the family. Analysis of plastid DNA rbcL sequences from 36 species representing the diversity of Ophioglossaceae supported the monophyly of the family. Intrafamilial relationships were examined using rbcL and trnL-F plastid DNA sequences and morphological data. Individual and combined analyses of the three data sets revealed two main clades within the family, here termed ophioglossoid and botrychioid. In the botrychioid clade, Helminthostachys was sister to a broadly defined Botrychium, within which Botrychium in the narrow sense of some authors and Sceptridium were sister. Botrypus was paraphyletic, with Botrypus virginianus sister to Botrychium plus Sceptridium, and with Botrypus strictus sister to all other botrychioid species except Helminthostachys. In the ophioglossoid clade, Ophioglossum in the narrow sense was sister to Cheiroglossa plus Ophioderma, but relationships within Ophioglossum were not well supported.     

Ultrastructural study of spore wall morphogenesis inOphioglossum thermale kom. var.nipponicum (Miyabe et Kudo) nishida

Spore wall morphogenesis ofOphioglossum thermale var.nipponicum was examined by transmission electron microscopy. The spore wall of this species consists of three layers: endospore, exospore, and perispore. The spore wall development begins at the tetrad stage. At first, the outer undulating lamellar layer of the exospore (Lo) is formed on the spore plasma membrane in advance of the inner accumulating lamellar layer (Li) of the exospore. Next, the homogeneous layer of the exospore (H) is deposited on the outer lamellar layer. Both lamellar layers may be derived from spore cytoplasm; and the homogeneous layer, from the tapetum. Then the endospore (EN) is formed. It may be derived from spore cytoplasm. The membranous perispore (PE), derived from the tapetum, covers the exospore surface as the final layer. Though the ornamentation of this species differs distinctly from that ofO. vulgatum, the results mentioned above are fundamentally in accordance with the data obtained fromO. vulgatum (Lugardon, 1971). Therefore, the pattern of spore wall morphogenesis appears to be very stable in the genusOphioglossum.     

GAMETOPHYTES AND YOUNG SPOROPHYTES OF OPHIOGLOSSUM CROTALOPHOROIDES WALT.

The lens-shaped, dorsiventral gametophytes of Ophioglossum crotalophoroides are superficially different from the cylindrical gametophytes of other species of Ophioglossum. However, they have the same features as other Ophioglossum gametophytes (fundamentally axial organization, radially symmetrical apical meristem, radial distribution of gametangia) except that the cylindrical axis is reduced in length. Young sporophyte development is unique in the genus: all primary organs clearly arise from the embryo and develop simultaneously. The length of the life cycle of O. crotalophoroicles is considerably shorter than that of some other species in the Ophioglossaceae. A timetable for gametophyte and young sporophyte development is postulated. Spores germinate soon after they are released in the spring, and mature gametophytes develop by the next growing season. Fertilization occurs approximately one year after spore dispersal, and after two years, the photosynthetic first leaf of the young sporophyte emerges.     

Chromosome evolution in the genus Ophioglossum L.

Cytological observations on eleven species of Ophioglossum revealed low gametic ( n ) chromosome numbers of 30, 34 and 60 in populations of O.eliminatum , contrasting with an earlier report of n = 90 in the same species. The rest of the species is based on n =120.Cytologically studied species of Ophioglossum exhibit a range of chromosome numbers from n = 30 in O.eliminatum to n =720 in O.reticulatum. The weighted highest common factor (HGF) from all the reported chromosome numbers in twelve species was found to be 30. This number is proposed as the palaeobasic chromosome number for the genuS. Reported chromosome numbers which are not multiples of 30 were subjected to sequential analysis, yielding three distinct ultimate base numbers, 4, 5 and 6, which can produce n = 30 in seven different ways. The neobasic number, n= 120, appears to have arisen through various combinations and permutations of these, theoretically 2401 routes; only a relatively few of these routes exist today, suggesting that extreme selection has been exerted against the majority, and further suggesting that Ophioglossum represents an evolutionary dead end through repeated cycles of polyploidy and is possibly at the verge of extinction. The stoichiometric model of evolution, which derives the various chromosome numbers possessed by the twelve species from the basic and ultimate basic chromosome numbers, is used to explain chromosomal evolution in the genus.     

High DNA content of Sprekelia formosissima Herbert (Amaryllidaceae) and Ophioglossum petiolatum Hook. (Ophioglossaceae)

Ophioglossum petiolatum and Sprekelia formosissima root tips were chemically determined to have 170± 12 pg and 180±12 pg DNA/cell respectively, or 2.8 and 3.0 times the 60±4 pg DNA/ cell of Tradescantia sp. clone 02 root tips. These values were compared with those predicted from nuclear volume measurements. General qualifications of the nuclear volume-DNA content relationship are discussed. Microspectrophotometrically determined relative DNA values for Feulgen stained half-telophase root tip nuclei of O. petiolatum and S. formosissima were 2.8 and 2.6 the value for Tradescantia. The value for Sprekelia is among the highest in the angiosperms, and Ophioglossum probably has the highest nuclear DNA content of ferns. O. petiolatum has 131±3 pg DNA per dormant spore.     

The morphological nature of the fertile spike in the Ophioglossaceae

KHANDELWAL, S., 1986. The morphological nature of the fertile spike in the Ophiogiossaceae. A study of a large collection of specimens belonging to 12 species of Ophioglossum revealed the presence of many abnormal structures in the tropophyll and the spike. These anomalous structures suggest that the fertile spike of Ophioglossum is derived from the modified pinnae of a compound leaf. Compound vegetative leaves are possessed by its allies Botrychium and Helminthostachys.     

Arbuscular mycorrhizal and septate endophyte fungal associations in lycophytes and ferns of south India

We studied extent and type of arbuscular mycorrhizal (AM) and septate endophytic (SE) fungal associations in five lycophytes and 50 ferns collected from Eastern and Western Ghats regions. Of the 54 species and one variety (belonging to 31 genera) examined; 54 taxa had AM association and AM fungal structures were absent in Marsilea quadrifolia. This is the first report of AM and SE fungal status for 26 species each. Of the 55 taxa examined, AM morphology has been evaluated for the first time in 51 species. The hydrophytic fern Salvinia molesta was mycorrhizal and non-mycorrhizal at different sites. All the epiphytic and saxicolous species examined were mycorrhizal. The percentage of AM colonization ranged from 22.23 (Christella parasitica) to 82.20 (Adiantum lunulatum) in ferns and 53.46 (Selaginella bryopteris) to 84.34 (Selaginella sp.) in lycophytes. Epiphytic life-forms had the maximum average AM colonization levels, whereas aquatic life-forms had the minimum colonization levels. The percentage root length colonized by septate fungi ranged between 0.59 in Ophioglossum reticulatum and 16.36 in Pteris pellucida. The root length with AM and SE fungal structures as well as their total colonization significantly varied among the taxa examined. Most of the lycophytes and ferns had intermediate-type of AM morphology with a few exhibiting Paris-type. AM fungal spore numbers ranged from 1.0 (Angiopteris evecta, Pteridium aquilinum) to (Nephrolepis exaltata) 9.3 spores per 25 g soil and varied significantly among taxa. AM fungal spore morphotypes belonging to Claroideoglomus, Funneliformis, Glomus and Rhizophagus were recorded.     

Thermotolerance and regeneration in the brittle star species complex Ophioderma longicauda: A preliminary study comparing lineages and Mediterranean basins

Global warming is expected to change marine species distributions; it is thus critical to understand species current thermotolerance. The brittle star species complex Ophioderma longicauda comprises a broadcast spawning lineage L1 and a brooding lineage L3. We collected L1 specimens from Marseilles and Crete, and L3 specimens from Crete. We monitored survival, autotomy and arm regeneration at 17, 26 and 30 °C during 14 weeks. Globally O. longicauda showed good resistance to elevated temperatures compared to other published studies on ophiuroids. The L3 sample displayed a better thermotolerance than L1 samples. Yet, more research is needed to establish whether these differences are due to lineages, geographic origin, or random effects. We provided for the first time individual regeneration trajectories, and showed that regeneration followed a growth curve and was highly influenced by temperature in both lineages. Our results highlight the importance of taking into account the presence of cryptic species when studying the potential effects of global warming.     

Genetic data,reproduction season and reproductive strategy data support the existence of biological species in Ophioderma longicauda

Cryptic species are numerous in the marine environment. The brittle star Ophioderma longicauda is composed of six mitochondrial lineages, encompassing brooders, which form a monophyletic group, and broadcasters, from which the brooders are derived. To clarify the species limits within O. longicauda, we compared the reproductive status of the sympatric lineages L1 and L3 (defined after sequencing a portion of the mitochondrial gene COI) during the month of May in Greece. In addition, we genotyped a nuclear marker, intron i51. Each L3 female was brooding, whereas all L1 specimens displayed full gonads, suggesting temporal pre-zygotic isolation between brooders and broadcasters. Statistical differences were found among lineages in morphology and bathymetric distribution. Finally, the intron i51 was polymorphic in L1 (60 individuals), but monomorphic in L3 (109 individuals), confirming the absence of gene flow between brooders and broadcasters. In conclusion, the broadcasting lineage L1 and the brooding lineage L3 are different biological species.