从无性生殖分析蕨类植物紫萁的原始特征

蕨类植物无性生殖过程中有诸多重要的分类和演化特征,利用光镜和扫描电镜观察紫萁科(Osmundaceae)代表植物——紫萁(Osmunda japonica Thunb.)孢子囊的形态和孢子形态,以及表面纹饰的形成过程。结果显示,紫萁具有如下原始特征:①孢子囊大型,无囊群盖,具盾状环带,孢子叶上的孢子囊同时发育,孢子囊纵向开裂;②孢子囊中孢子数量多;③孢子同型,具三裂缝,为辐射对称的四面体型;④孢子表面由外壁构成的纹饰形成过程复杂。从无性生殖角度显示紫萁科在真蕨类植物中古老的演化地位。     

中国产桫椤类配子体在不同基质胁迫下的形态畸变多样性研究

为了明确土壤污染对中国产桫椤科植物的生殖影响,以探讨中国桫椤类乃至其他濒危蕨类濒危的内在原因。该研究以中国产9种桫椤植物为材料,采用各植物原产地地表土壤培养孢子至配子体成熟,全程比较观察配子体畸变类型,统计畸变率;并分别取3个属的代表种笔筒树、大叶黑桫椤和中华桫椤的孢子,以MS培养基为对照,分别用5mg·kg^-1Pb^2+和1mg·kg^-1Cd^2+单因素胁迫培养配子体,比较观察各组的配子体形态畸变类型,统计畸变率。结果表明:(1)中国产桫椤类9种植物配子体培养过程中共出现17种形态畸变类型,其中4种为分化畸变,7种为假根畸变,4种为细胞畸变,2种为性器畸变。(2)不同培养基——对照组(MS培养基)、原产地土壤、Cd^2+胁迫、Pb^2+胁迫对中国产桫椤科9种植物配子体的平均畸变比例分别是2.28%、12.61%、31.58%和33.58%。(3)9种桫椤的配子体畸变类型及其畸变率均与培养基的胁迫程度呈正相关关系,其配子体发育都受到了产地土壤污染的严重伤害。(4)3种桫椤属植物配子体对土壤环境胁迫的耐受力强弱为黑桫椤属>白桫椤属>桫椤属。(5)桫椤科配子体的形态畸变多样性与胁迫条件之间具有稳定的对应关系。     

双性封印木孢子叶球在内蒙古乌达煤田下二叠统太原组凝灰岩层中的发现

封印木在石炭纪–二叠纪欧美植物群的沼泽森林中占据重要地位,化石记录十分丰富,在华夏植物群中的记录则较为稀少。已知这类植物的孢子叶球都是单性的。本文基于内蒙古乌达煤田下二叠统太原组凝灰岩中的化石材料,报道了一种石松类双性孢子叶球类型,与封印木茎干及叶保存于原位埋藏的火山凝灰岩植物群中,共同构成封印木树冠。该类孢子叶球呈圆柱形,基部具柄;孢子叶紧密螺旋排列,近轴部分为水平伸出的孢子叶柄,远轴部分为上翘的远端叶片,两者转折处具明显的踵;孢子囊单生于孢子叶柄近轴面,大孢子囊位于孢子叶球的中部-基部,小孢子囊位于中部-顶部。该类双性封印木孢子叶球的发现增加了封印木繁殖器官的多样性和复杂性,为进一步探讨这类植物的系统分类与演化提供了重要信息。     

大叶黑桫椤孢子超低温保存

大叶黑桫椤孢子在液氮中长期保存的结果表明：（1）大叶黑桫椤孢子可以保存于液氮中;（2）液氮保存后的孢子萌发率比未用液氮保存的普遍下降,保存90d的用室温慢速化冻的孢子萌发率最高（65.3％）,相对保持率最高可达79.3％;（3）采用室温（22～25℃）慢速化冻的效果优于37℃温水浴快速化冻的。据此认为,液氮超低温长期保存大叶黑桫椤孢子是可行的。     

中国桫椤科植物的分类

本文记载了我国14种和2变种桫椤科植物及其分布。根据叶柄基部的鳞片,叶轴背面 两侧的气囊体,叶轴的颜色,囊群盖以及孢子数目等性状,把它们安排在2属2亚属中,并讨论了各类群之间可能的演化关系。     

蕨类植物孢子囊形态 I. 鳞始蕨科

孢子囊是蕨类植物的繁殖器官, 其形态在蕨类植物的分类和系统发育研究上具有重要意义。用次氯酸钠溶液处理新鲜成熟的孢子囊, 在光学显微镜下获得清晰的孢子囊图像, 系统研究了中国鳞始蕨科4属13种孢子囊的形态特征。结果表明, 鳞始蕨科孢子囊呈椭球形, 孢子囊柄由3列细胞构成, 环带类型为垂直环带。通过分析孢子囊形态数据探讨了中国鳞始蕨科属内及属间差异。结果表明, 乌蕨属(Odontosoria)、香鳞始蕨属(Osmolindsaea)、达边蕨属(Tapeinidium)和鳞始蕨属(Lindsaea)的孢子囊环带细胞数依次减少, 囊蒴体积、唇细胞数和囊壁细胞数的变化由大(多)到小(少)依次为乌蕨属、达边蕨属、香鳞始蕨属和鳞始蕨属。孢子囊属内差异最大的是阔片乌蕨(Odontosoria biflora)与乌蕨(O. chinensis)以及香鳞始蕨(Osmolindsaea odorata)与日本鳞始蕨(O. japonica); 而达边蕨属和鳞始蕨属的属内差异则很小。研究结果为揭示鳞始蕨科系统发育关系提供了形态基础, 特别是提出阔片乌蕨和乌蕨以及香鳞始蕨和日本鳞始蕨在孢子囊形态上的差异值得进一步研究。     

蕨类植物孢子囊形态Ⅰ.鳞始蕨科

孢子囊是蕨类植物的繁殖器官,其形态在蕨类植物的分类和系统发育研究上具有重要意义。用次氯酸钠溶液处理新鲜成熟的孢子囊,在光学显微镜下获得清晰的孢子囊图像,系统研究了中国鳞始蕨科4属13种孢子囊的形态特征。结果表明,鳞始蕨科孢子囊呈椭球形,孢子囊柄由3列细胞构成,环带类型为垂直环带。通过分析孢子囊形态数据探讨了中国鳞始蕨科属内及属间差异。结果表明,乌蕨属(Odontosoria)、香鳞始蕨属(Osmolindsaea)、达边蕨属(Tapeinidium)和鳞始蕨属(Lindsaea)的孢子囊环带细胞数依次减少,囊蒴体积、唇细胞数和囊壁细胞数的变化由大(多)到小(少)依次为乌蕨属、达边蕨属、香鳞始蕨属和鳞始蕨属。孢子囊属内差异最大的是阔片乌蕨(Odontosoria biflora)与乌蕨(O.chinensis)以及香鳞始蕨(Osmolindsaea odorata)与日本鳞始蕨(O.japonica);而达边蕨属和鳞始蕨属的属内差异则很小。研究结果为揭示鳞始蕨科系统发育关系提供了形态基础,特别是提出阔片乌蕨和乌蕨以及香鳞始蕨和日本鳞始蕨在孢子囊形态上的差异值得进一步研究。     

基于群落种间关系的桫椤植物保护策略研究进展

桫椤科植物是古老的孑遗植物,现存的桫椤天然群落极为罕见,为了解桫椤(Alsophila spinulosa)及桫椤科(Cyatheaceae)植物在生物群落的中生存与保育状态研究现状,本文通过搜集国内外关于桫椤及桫椤科植物相关文献进行研究。桫椤科植物分布于高温潮湿、光斑直射的生境,常以斑块状分布于常绿阔叶林林缘。现阶段,桫椤科植物保护面临的主要问题是生态旅游、毁林开荒、环境污染、药材的违法采摘和挖掘等,这导致桫椤科植物的生境遭受干扰和破碎,桫椤科植株数量下降。对桫椤科植物的保护方式主要有就地保护、迁地保护,分子生物学技术在桫椤科植物繁育中应用逐渐增加。生物和非生物因素制约着桫椤科植物的分布和多样性,其中,生物因素特别是种间关系对桫椤植物的生长发育和分布有着重要影响,从种间关系的视角出发探讨桫椤科植物的保护或许不失为新时代桫椤科植物保护的有效方式。讨论了桫椤植科物相关的种间关系：桫椤科植物-微生物互作、桫椤科植物-其他植物互作、桫椤科植物-动物互作,探讨了桫椤科植物面临灭绝的因素以及近年来桫椤科植物相关的保护策略及成效,为桫椤科植物的有效利用和保护提供一定理论基础。     

中国蕨类植物孢子的形态Ⅶ.桫椤科

对中国桫椤科(Cyatheaceae)11种植物的孢子形态进行了扫描电镜的研究。桫椤科孢子辐射对称,三裂缝,裂缝长度达孢子半径的3/4左右,极面观三角形,赤道面观为半圆形或扇形,孢子极轴长为27~42μm,赤道轴长为32~52μm。孢子表面纹饰是由周壁形成的,可分为4种类型,即条纹状、疣状、刺条状、短刺状。根据孢子的形态特征,对中国桫椤科孢子类型进行了划分,对属的划分问题进行了探讨。     

中国蕨类植物孢子的形态Ⅶ . 桫椤科

对中国桫椤科(Cyatheaceae ) 11 种植物的孢子形态进行了扫描电镜的研究。桫椤科孢子辐射对称, 三裂缝, 裂缝长度达孢子半径的3/4 左右, 极面观三角形, 赤道面观为半圆形或扇形, 孢子极轴长为27～42μm, 赤道轴长为32～52μm。孢子表面纹饰是由周壁形成的, 可分为4 种类型, 即条纹状、疣状、刺条状、短刺状。根据孢子的形态特征, 对中国桫椤科孢子类型进行了划分, 对属的划分问题进行了探讨。     

爬树蕨的解剖学研究

本文对爬树蕨（Ａｒｔｈｒｏｐｔｅｒｉｓｏｂｌｉｔｅｒａｔａ（Ｒ．Ｂｒ．）Ｊ．Ｓｍ）孢子体各主要器官进行了解剖学研究及对孢子进行了电子显微镜扫描观察,研究结果表明;茎的中柱具有两个新月形的维管束;幼茎的中部有髓．在较老的茎,髓部及中柱周围的细胞均特化为厚壁细胞．根属二原型中柱．木质分化方式是外始式;在对正后生木质部的两侧的皮层有几层特化为厚壁细胞。叶的叶肉细胞不分化出栅栏组织和海绵组织,为等面对。孢子囊具有纵向环带,孢子的形状、外壁的纹饰和裂缝情况均与以前的研究有所不同。     

Sporangium Exposure and Spore Release in the Peruvian Maidenhair Fern (Adiantum peruvianum,Pteridaceae)

We investigated the different processes involved in spore liberation in the polypod fern Adiantum peruvianum (Pteridaceae). Sporangia are being produced on the undersides of so-called false indusia, which are situated at the abaxial surface of the pinnule margins, and become exposed by a desiccation-induced movement of these pinnule flaps. The complex folding kinematics and functional morphology of false indusia are being described, and we discuss scenarios of movement initiation and passive hydraulic actuation of these structures. High-speed cinematography allowed for analyses of fast sporangium motion and for tracking ejected spores. Separation and liberation of spores from the sporangia are induced by relaxation of the annulus (the ‘throwing arm’ of the sporangium catapult) and conservation of momentum generated during this process, which leads to sporangium bouncing. The ultra-lightweight spores travel through air with a maximum velocity of ~5 m s^-1, and a launch acceleration of ~6300g is measured. In some cases, the whole sporangium, or parts of it, together with contained spores break away from the false indusium and are shed as a whole. Also, spores can stick together and form spore clumps. Both findings are discussed in the context of wind dispersal.     

Systematics of the genus Ceratopteris Brongn. (Parkeriaceae) II. Taxonomy

A revision of the genusCeratopteris is presented based on comparative morphology and geographical distribution. Four species are recognized:C. thalictroides, C. cornuta, C. pteridoides, andC. richardii. Characteristics of taxonomic importance include frond length, shape, and dissection; stipe width; insertion of basal pinnae; bud development; habit; annulus cell number; spore number per sporangium; spore size; and spore surface features. Evolution within species and putative hybridization between species are discussed.     

Permanent dyads in sporangia and spore masses from the Lower Devonian of the Welsh Borderland

Dyads, interpreted as cryptospore permanent dyads, are reported from sporangia and spore masses recovered from fluviatile deposits of Lochkovian (Early Devonian) age from the Welsh Borderland. The morphology, anatomy and ultrastructure of the specimens have been analysed using LM, SEM and TEM. Two specimens consist of a single sporangium terminating an axis: one is cup-shaped and attached to an unbranched axis and named Culullitheca richardsonii gen. et sp. nov., the other comprises an isotomously branching axis with one sporangium preserved and is named Fusitheca fanningiae gen. et sp. nov. Two specimens show dyads adhering to cuticular fragments presumably derived from sporangia. In one the cuticle is of irregular shape, in the other it is elliptical. The final specimen comprises an elongate spore mass. In all cases ultrastructural analysis reveals that the spore walls are essentially homogeneous. Our findings suggest that cryptospore permanent dyads were produced by rhyniophytoid plants of small stature. The affinities of these plants remain conjectural, as is the relationship of the cryptospore permanent dyads with other sporomorph morphotypes (cryptospores and trilete spores). However, the production of dyads by a plant with a bifurcating sporophytic axis is evidence against affinity with extant bryophytes. The mode of formation, adaptive significance, affinities, phylogenetic relationships and stratigraphical history (including demise) of cryptospore permanent dyads is discussed.     

沙棘根瘤内生菌的多型性

用透射电子显微镜观察了春、夏、秋、冬四个季节的沙棘根瘤,以及瘤瓣上、中、下三个部位。结果表明,不同季节,不同部位的瘤瓣内,根瘤内生菌有7种不同形态。即侵染菌丝体、繁殖菌丝体、营养菌丝体、春孢子及春孢子囊、泡囊,冬孢子及冬孢子囊和类菌体。在多年生珊瑚状的根瘤中,它们的世代交替是:春夏季以侵染菌丝、繁殖菌丝、营养菌丝、春孢子囊及春孢子、泡囊为主;秋冬季以衰退的营养菌丝、衰老泡囊、冬孢子囊和冬孢子、类菌体为主。冬孢子和类菌体是休眠体。     

Ultrastructure of laevigate hilate spores in sporangia and spore masses from the Upper Silurian and Lower Devonian of the Welsh Borderland

Spore masses and isolated sporangia, containing laevigate hilate cryptospores attributable to the dispersed taxon Laevolancis divellomedia sensu lato, have been recovered on bulk maceration of Upper Silurian (Pridoli) and Lower Devonian (Lochkovian) deposits from the Welsh Borderland. Detailed morphological, anatomical and ultrastructural analysis, using light microscope, scanning electron microscope and transmission electron microscope techniques, reveals subtle differences between the specimens and they can be grouped into five distinct types. The different groups are distinguished principally by using sporangia-spore mass characteristics, presence or absence of extra-exosporal material and nature of spore-wall ultrastructure. Of the groups, one has a uniformly homogeneous exospore and the other four groups have a bilayered exospore. In the former the spores lack extra-exosporal material and occur in a discoidal sporangium. Of the bilayered groups, two have exospores of homogeneous composition but with the two layers differing in electron density. They occur in discoidal sporangia and spore masses and are distinguished on the presence or absence of extra-exosporal material and differences in the widths of the two layers. Finally, two bilayered groups possess a lamellate inner layer, but vary in presumed sporangial shape. Elongate sporangia have spores with concentric continuous lamellae, lacking further ultrastructure. In contrast, spores from a discoidal spore mass have white-line-centred, presumably tripartite, lamellae which are laterally discontinuous, overlapping and irregularly spaced. These findings, which suggest that morphologically similar spores were produced by a number of plant taxa, have important implications regarding the assessment of early land-plant diversity. The affinities of hilate cryptospore-producing plants are unknown and problematic, particularly as no extant non-angiosperm plants produce dyads, other than through meiotic irregularity, and spore-sporangial characters have no exact counterpart in coeval plants. Studies of specimens with in situ hilate cryptospores suggest that they derive from rhyniophytoids, i.e. plants that resemble the simplest of vascular plants but lack evidence of vascular tissue, although hilate cryptospore-containing examples show no axial branching. It might be argued, based on evidence from spore wall ultrastructure, that some of the plants have more in common with lycopsids and filicopsids than bryophytes, a surprising finding bearing in mind the stratigraphic distribution of hilate cryptospores-dyads and inferences that the producers were bryophyte-like. Detailed studies of wall structure in the hilate cryptospores permit consideration of spore wall development. It is suggested that extra-exosporal material derives from a tapetum and is thus produced by the diploid sporophyte. The white-line-centred lamellae in a single specimen provide the earliest evidence for the presence of such structures in early land plant spores and provide further evidence that sporopollenin deposition on such structures is the most primitive mode of sporopollenin deposition among land plants.     

Competition between species of the aestivo-autumnal group of birch pests for food in Transuralia

The aestivo-autumnal group of birch pests includes 25 species belong to the Notodontidae, Geometridae, Noctuidae, and other families. The larvae of all its species hatch out in mid-July and feed until the end of August. On emerging from the eggs they spread from leaf to leaf, but as the food supply diminishes they crowd together and competition is intensified. The species structure of the group shows some variation over the territory, and only a few species dominate, different species in different places. It is suggested that improvement in the food supply leads to mass reproduction. Biochemical investigations confirmed this hypothesis: different species feeding on the same leaf assimilate different amino acids more completely, and their relative numbers on the leaves vary in different parts and at different times. The composition of secondary metabolites important for resistance of the plants also varies.     

宽带蕨属（水龙骨科）的系统学研究

对喜马拉雅和横断山地区特有的水龙骨科的宽带蕨属Platygyria Ching&S.K.Wu植物进行了形态学、分类学、生态和植物地理学的观察与分析,探讨了该属植物的系统位置、亲缘关系和生态适应性,推测宽带蕨属是随着喜马拉雅山脉的隆升,由瓦韦属Lepisorus（J.Sm.）Ching网眼瓦韦群植物适应高寒生态环境演化而来的新生类群。确定宽带蕨属有5种,即川西宽带蕨P.soulieana（Christ）X.C.Zhang&Q.R.Liu、多变宽带蕨P.variabilis Ching&S.K.Wu、耳基宽带     

中华水韭孢子囊发育研究

采用半薄切片法,连续观察了极度濒危级(CR)植物中华水韭大小孢子囊的发育过程,以期从无性生殖的角度,为探讨其濒危原因提供直观可靠的理论根据。结果显示:(1)中华水韭的大小孢子叶相间排列,无混生孢子囊。(2)隔丝为孢子供给营养,其体积直接影响孢子的大小、产量和育性。(3)大小孢子囊都近半数败育,小孢子囊为整齐发育,大孢子囊为不整齐发育。(4)大小孢子囊均无柄,且都不存在开裂结构,只有孢子囊壁腐烂后才能散播孢子。研究认为,中华水韭的濒危与孢子囊的发育特征密切相关,孢子囊的高频率败育、没有开裂结构以及对环境的依赖,是造成中华水韭濒危的重要因素之一;通过与近缘类群孢子囊的比较,发现仅水韭孢子的散播借助外力,对生境要求较高,即验证了水韭古老的系统学地位,同时说明水韭更具有监测生境地区环境指标的能力。