中泥盆世草本石松植物原始鳞木属的命名问题

草本石松植物原始鳞木属（Protolepidodendron）一名,最初由Krejci根据波希米亚泥盆纪地层中一种具叶的茎干标本所建立,当时为了强调其与石炭纪鳞木属（Lepidodendron）石松植物的相似性,取名为Proto-Lepidodendron。后来,这种以具有二分叉的叶为特征的草本石松植物相继在捷克、德国、比利时、美国、中国、哈萨克斯坦、俄罗斯等地的早、中泥盆世地层中被发现。值得一提的是,对该属及模式种的命名问题存在一定的争议,同时存在多种作者引证,甚至还存在不同拼写的种本名。根据国际植物学命名法规,对化石植物的命名必须依据模式标本。目前,Protolepidodendron的模式标本保存在捷克共和国首都布拉格的国家博物馆。通过对模式标本进行的重新观察,并发现Gothan（1921）首次根据模式标本明确了Protolepidodendron的属征,是该属最早的合格发表作者;后来,模式标本又经过Krausel和Weyland（1929）的研究,唯一合法的种P．scharyanum被确立为模式种,并提出了种征。对Protolepidodendron属及其模式种,尽管后来有大量研究和报道,但都不是基于原始的模式标本。因此。根据国际植物学命名法规,该属及其模式种的合法名称应为Protolepidodendron Krejci ex Gothan和P．scharyanum Krejci ex Krausel et Weyland。     

On Occurrence and Significance about the Fossil Plants from the Yuntaiguan Formation Located between Hunan and Hubei

This paper deals with the fossil plants from the Yuntaiguan formation located between Hunan and Hubei province. There are six genera and ten species (containing a new genus and five new species) to be discussed here, such as Protolepidodendron scha-ryanum Krejci, Barrandeina dusliana (Krejci) Stur, B. contigua sp. nov., B. lixianensis sp. nov., B. multistriata sp. nov., B. laxa sp. nov., Drepanophycus spinaeformis Goepp., “Protopteridium”? minutum Halle, Psilophyti4es sp. and Longostachys latisporophyllus gen. et sp. nov., etc. The appearance of this fossil flora concerned here can be correlated to the Protolepidodendron scharyanum-Barrandeina dusliana Assemblage. Among these fossil plants from Yuntaiguan formation, both the Protolepidodendron scharyanum and Barrandeina dusliana are also the index fossils, the prior was wide spread during the Middle Devonian in whole world and the other was only found at the late Middle Devonian in Europe. In the Yuntaiguan formation the genus Barrandeina containing no less than five species and, the other taxa were also found from the Middle or the late Middle Devonian. So that this formation should be referred to the late Middle Devonian in age and this conclusion corresponds with the result of spore-pollen analysis in the Xiushuigou formation, Xiongzi county, which is similar to the Yuntaiguan formation and has been referred to the Middle Devonian. In this paper, only four species of Barrandeina and one species of Longostachys have been described, those of the former have not been found before in China. The authors think; this will be significant on studying fossil plants and in comparison with the age of the strata.     

The Distribution of Cytoplasmic Vesicles, Multivesicular Bodies and Paramural Bodies in Elongating Sporangiophores and Swelling Sporangia of Thamnidium elegans Link

In Thamnidium elegans Link, cytoplasmic vesicles of variablesize were present in large numbers in sporangiophore apicesin agar and in smaller numbers in sporangiophore apices in air.Golgi-like cisternae were associated with small, sub-apicalclusters of vesicles. Apices in agar contained a nucleus andmitochondrion-free tip zone in which vesicles were concentrated.This zone was almost completely absent from apices in air. Inswelling sporangia, vesicles were sparce and were not concentratedagainst the wall. Rates of surface area increase were similarfor sporangiophores elongating, respectively, in agar and inair. Rates of surface area increase during sporangium swellingwere equal to or greater than rates of surface area increaseduring sporangiophore elongation. Vesicles were associated withformation of a secondary wall layer in swollen sporangia. Paramuralbodies and multivesicular bodies were present at all stagesof sporangiophore elongation and sporangium swelling. Isolatedhalo bodies (apical corpuscles) were present in walls at sporangiophoretips, and clusters of similar bodies were present in side wallsof sporangiophores.     

荔枝霜疫霉的研究

对华南的荔枝霜疫霉(Peronophythora litchii Chen ex Ko et al)的形态和营养特性进行了研究,并和新模式种进行了比较。发现此菌孢囊梗的生长是一种有限-无限生长类型,或称之为多级有限生长。即孢囊梗上的小分枝大多数是有限生长的,在其顶端同时形成孢子囊。但有时在同一孢囊梗上有的小分枝会继续生长,形成二级、三级甚至四级孢囊梗。在营养要求上与疫霉无大差别,能在天然和合成培养基上旺盛生长,需要硫胺素,ca~(++)和有机二元酸,能利用NH_4~+ 或No_3~-为其氮源,并能利用淀粉为其碳源,菌体匀浆中测出淀粉酶活性。根据孢囊梗的独特生长方式,我们认为完全有理由承认这菌是一个新属,并可成为新科,霜疫霉科。本文中已将霜疫霉科作了修改描述。孢囊梗已被修改为:孢囊梗多级有限生长。无疑这菌是腐霉科和霜霉科的中间类型。在营养类型与有性器官上和疫霉相近,而其孢子囊的形成和霜霉相似。但其孢囊梗的多级有限生长方式则和这两科都不相同。     

Positional differentiation for development along the sporangiophore in <Emphasis Type="Italic">Phycomyces blakesleeanus</Emphasis>

 Small segments of Phycomyces sporangiophores regenerate various structures on incubation in a moist chamber. We tested the regeneration capacities of middle sporangiophore segments whose protoplasm had been totally or partially removed and replaced with protoplasm from various segments of a genetically different strain. The structures that were regenerated depended on the source of the injected protoplasm (sporangia of various sizes and segments from middle and basal parts of the sporangiophores), implying a positional differentiation of protoplasm along the sporangiophore axis. Protoplasm from various sources showed a high affinity; that is, they mixed successfully and led, in most cases, to the formation of heterokaryotic regenerating structures. The highest affinity was seen when mixing protoplasm from the middle segments of two different strains. Received: November 29, 2000 / Accepted: March 19, 2002     

Estinnophyton wahnbachense (Kräusel et Weyland) comb. nov., une plante remarquable du siegenien d'allemagne

Specimens collected from the type locality of Protolepidodendron wahnbachense Kräusel et Weyland 1932 (Germany) are studied. The narrow axes, with persistent leaves which are bifurcated and spirally arranged, resemble those of P. wahnbachense. However, the vegetative and fertile leaves bifurcate twice and the four resulting segments are spread in various planes; the fertile leaves support two pairs of stalked elongate sporangia which are directed towards the axis. Estinnophyton wahnbachense (Kräusel et Weyland) comb. nov. is thus proposed as a name for these Siegenian plant remains, the questionable affinities of which are discussed.     

Piromyces citronii sp. nov., a strictly anaerobic fungus from the equine caecum: a morphological, metabolic, and ultrastructural study

Abstract Piromyces citronii sp. nov. was isolated from the caecum of one pony and three donkeys. It differed from other anaerobic fungal species in that it had a filamentous monocentric thallus composed of a globular or elliptic sporangium, which was occasionally bifid or trifid (monocarpic thallus), or several sporangia (polycarpic thallus), with a short sporangiophore. P. citronii also differed from other species in that it did not grow with starch or maltose as carbon source and it did not produce d-lactate. The uniflagellate zoospores presented a standard ultrastructure.     

On Plant-Remains from the Devonian of Yunnan and their Significance in the Identification of the Stratigraphical Sequence of this Region

The present paper treats of three plant-remains recently collected in the district Chu-tsing, East Yunnan. They are Zosterophyllum yunnanicum sp. nov., Protopteridium minuturn Halle and Sporogonites yunnanense sp. nov., and their distinctions from the related species from the other parts of the world are rather fully discussed. In addition, the paper further discusses the geological age of the region wherefrom these and other plant-remains have been collected. Zosterophyllum yunnanicum is preserved in a bed of dark greyish sandy clay in the locality Hsu-Chia-Chong in the district Chuitsing, East Yunnan. It is associated with Drepanophycus spinaeformis Goeppert. This bed belongs to the uppermost layer of the Tsuifengshan Series. The diagnosis of Zosterophyllum yunnanicumsp, nov. is given as follows: A small plant with slender erect axes, about 1-1.3 mm across and sparingly dicho- tomous branches, axis possessing a slender central vascular strand. Sporangia are short-stalked, closely and radially arranged on the upper part of the erect axis to form a compact strobilus, up to 5 cm long. Each strobilus consists of about 40–50 sporangia which are roundish to reniform, about 1.9–2.7 mm across, and about 9.4 mm thick; dehiscence by a slit running along the convex upper edge. Epidermal cells of the axis and the sporangium are elongate-fusiform, about 360 μ long and 45-90μ wide. Zosterophyllum yunnanicum agrees with Z. myretonianum Penh. and Z. australianum in general morphology, but smaller in size. The genus Zosterophyllum has so far been recorded only from the Late Silurian of Australia and England and the Early Devonian of England, Scotland, France, Germany, West Siberia and North America. Remains of axes with H-shaped branching (cf. Zostero- phyllum) have previously been recorded by the present author from the district Chutsing (Hsu 1947, 354-355. Pl. V, Fig. 52 and text-figs. 5 a-c), but the actual locality and horizon were then unknown. So the present discovery of Z. yunnanicum helps to settle the question of the Tsuifengshan Series which is definitely not younger than the Late Devonian in age. Protopteridium minutum and Sporogonites yunnanense were found in a bed of light grey sandstone in the locality Lunghuashan of the same district, from where the type of Protopteridium minutum Halle was collected. From the same bed some fragments of Protolepidodendron scharyanum Krejci were observed. This bed belongs to the uppermost layer of the Lunghuashan Series. From the lower part of the same series fragments of Drepanophycus spinaeformis Goeppert were also collected. It is interesting to note that under a critical investigation by the present author, it conclusively proves that Proto-pteridium minutum is not a small plant, as Halle first described. It attains a height of at least 1 meter. The main axis measures about 1.8 cm in diameter. Both the larger and the smaller specimens show sympodial development. Unequally dichotomous branching has been found only in some primary and secondary lateral branches. Most of the lateral branches are pinnulelike and subdivide 4–6 times, each possessing a slender central vascular strand. If the terminology of Zimmermann is adopted, the type of branching may be described as "Oscillating overtopping". However, some slender branches have been observed. These branches are sparingly unequally dichotomous, forking 6–7 times, and appear to be thinner than those just mentioned. Young branches are circinately coiled. Sporangia are arranged in clusters, 2-4-8 in number, attached to the terminal branches. These sporangia are 0.9 mm long, fusiform or sometimes almost cylindrical. Some larger obovate ones are about 2.5 mm long and borne singly, or in 2 (rarely in 4) in each tassel on the top of the flattened lateral branches. Epidermal cells of the axes are elongate, about 136 Ft long and 45.5 μ wide, while those of the smaller sporangia are oblong-fusiform, about 100–150 μ long and 25 μ wide and those of the larger, about 130–230μ long and 40–70μ wide. No annulus is observed. Sometimes mineral grains, occupying the interior of the sporangia, are observable through a longitudinal slit in the wall and thus give false markings of cells. Evidently, the plant-body of Protopteridium minutum is much more complex than Halle thought. A new reconstruction of it is drawn here to replace that given by Halle in 1936. It is considered that Protopteridium minutum is more closely related to P. hostimense Krejci than to others. The former is also complex in the vegetative branches, but simpler in the fertile ones. Sporogonites yunnanense is represented only by some detached capsules, hich are elongate-obovate, measuring about 3.2–4.5 mm long and 1.4–1.8 mm wide. These capsules are borne on the top of a slender stalk, measuring about 0.4–0.8 mm across. The younger ones look rather smooth, but the mature ones exhibit 12 longitudinal ridges, separated by shallow grooves, 6 ridges being visible on the surface exposed. Epidermal cells of the wall of the capsules are elongate, 150μ long and 50 μ wide. No stomata could be made out among them. Sporogonites yunnanense closely resembles S. exaberans Halle of the Early Devonian, but the capsules of the former exhibit variable forms and the upper end of the capsules is rather more pointed than those of the latter. Owing to the occurrence of Drepanophycus spinaeformis and the general aspect of the flora so far known, the author suggests that the geological age of the Lunghuashan Series is of the Middle Devonian or probably the Early Eifelian. The flora of the Tsuifengshan Series is predominated by Drepanophycus spinaeformis and Zosterophyllum yunnanicum, thus indicating that its geological age is no doubt of the Early Devonian.     

PALAEOSTACHYA DIRCEI N. SP., AN AUTHIGENICALLY CEMENTED EQUISETALEAN STROBILUS FROM THE MIDDLE PENNSYLVANIAN OF SOUTHERN ILLINOIS

Equisetalean strobili normally are encountered as disarticulated organs. This condition has necessitated the creation of 12 form genera to accommodate the various morphological architectures and anatomical configurations. Taxonomically useful characteristics, which are discernable in permineralized specimens, are rarely distinguishable in coalified compressions due to their destruction during diagenesis and coalification. Therefore, genera established on the position of sporangiophore-trace origin, such as Schimperia Remy and Remy, are untenable when dealing with coalified compressions. Although the two largest genera of strobili, Calamostachys Schimper and Palaeostachya Weiss, may be synonymous, it is proposed that these form genera be retained when dealing with coalified compression specimens. Each genus provides a particular architectural concept for specimens which may not be assignable to the species level. Calamostachys and Palaeostachya are highly overspeciated genera. It is suggested that characteristics necessary to delimit new species include bract height, degree of bract fusion, disposition of bracts, bract: sporangiophore ratio, number of sporangia per sporangiophore, and sexual status.     

Cell cycle regulator Cdc14 is expressed during sporulation but not hyphal growth in the fungus-like oomycete Phytophthora infestans

Cdc14 proteins are important regulators of mitosis and the cell cycle. These phosphatases have been studied previously only in yeasts and metazoans, which grow by fission or budding. Here we describe a homologue (piCdc14) from the oomycete Phytophthora infestans, a primitive eukaryote lacking a classical cell cycle. PiCdc14 complements a cdc14ts mutant of Saccharomyces cerevisiae and may function like other Cdc14 proteins, but displays a strikingly different pattern of expression. Whereas previously studied Cdc14 genes are constitutively transcribed, piCdc14 is not expressed during normal growth but instead only during asexual sporulation. In transformants of P. infestans expressing a fusion between the piCdc14 promoter and the -glucuronidase reporter, expression was first detected in sporangiophore initials, persisted in sporangiophores bearing immature sporangia, and later became restricted to mature sporangia. After germination, expression ended a few hours before the resumption of mitosis in hyphae emerged from the spores. Homology-dependent silencing experiments supported an essential role of piCdc14 in sporulation. It is proposed that the function of piCdc14 may be to synchronise nuclear behaviour during sporulation and maintain dormancy in spores until germination. These results help illuminate the process of sporulation in oomycetes and the evolution of the cell cycle in eukaryotes.     

Electron microscopic observation of the sporangial structure of strains of Actinoplanaceae

Lechevalier, Hubert A. (Rutgers, The State University, New Brunswick, N.J.), Mary P. Lechevalier, and Pauline E. Holbert. Electron microscopic observation of the sporangial structure of strains of Actinoplanaceae. J. Bacteriol. 92:1228-1235. 1966.-Eight strains of Streptosporangium spp. and one strain each of Spirillospora albida and an Ampullariella-like Actinoplanes sp. were observed by electron microscopy. The sporangiospores of all these organisms had a smooth surface. All formed their sporangia by the ingrowth of a hypha inside a bag formed by the extension of the outer sheath of the sporangiophore. The sporogenic hypha was not branched in strains of Streptosporangium but was branched in S. albida and the Actinoplanes sp. Spore formation was by septation of the intrasporangial hyphae. When it occurred, septation took place by the same annular ingrowth of the cell wall common in gram-positive bacteria. The septum at the apex of the sporangiophore was formed before the others. Septation was seen to occur between two fully formed septa, indicating almost simultaneous formation of large segments dividing again, almost simultaneously, into smaller spore-sized segments.     

“Lycostrobus” chinleana,an equisetalean cone from the Upper Triassic of the southwestern United States and its phylogenetic implications

Detailed study of the cone Lycostrobus chinleana Daugherty shows that the fossil was incorrectly attributed to the Lycopodiales by the author and to the quillworts by Retallack and that it actually should be assigned to the Equisetales. The cone, which occurs in the Upper Triassic Chinle Formation at several localities in the southwestern United States, is ∼2.5 cm wide and nearly 6 cm long and consists of a stout axis bearing whorls of peltate sporangiophores. Each sporangiophore is composed of a slender stalk and a hexagonal disk, which typically bears a single, generally long, lanceolate, forward-directed leaf-like umbo tip on the outer surface and several recurrent sporangia on the inner surface. Small round to oval trilete spores occur in the sporangia. Since the leaf-like umbo tip is similar to the sterile leaves found in certain calamite cones and the recurrent sporangia are equisetalean-like, it appears that the cone may represent a intermediate stage between Calamites and modern Equisetum. According to this hypothesis, the nonbracteate Equisetum cone could have developed from a bracteate calamite cone, through reduction and fusion of the bracts and the sporangiophores, rather than by the loss of whorls of bracts of the Calamites cone as suggested earlier by others. As a result of this study the cone is assigned to the new Equisetalean genus Equicalastrobus and redescribed under the name E. chinleana (Daugherty) Grauvogel-Stamm and Ash, n. comb.     

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。     

ON THE STRUCTURE OF CALAMOSTACHYS BINNEYANA FROM THE LOWER PENNSYLVANIAN OF NORTH AMERICA

The discovery of specimens of Calamostachys binneyana in Lower Pennsylvanan petrifaction material in North America has provided additional information about the structure of this calamitean fructification. The cones consist of regularly spaced alternating whorls of bracts and sporangiophores. Bracts are fused in a disc except at the margin where the individual units become free. Sporangiophores are inserted at right angles to the cone axis and bear four axially directed sporangia. The vascular system of the North American specimens differs from that in other reports of the taxon in the presence of twelve vascular bundles in the cone axis. Each sporangiophore is supplied by a single vascular trace that departs from one axial bundle. There appears to be no constant relationship between the number of vascular bundles and the number of bracts. Spores are spherical, thin-walled, and of the Calamospora type. Relationships with other structurally preserved members in the genus are discussed in light of the diversity in structure demonstrated by the new specimens.     

Spiral growth in the radially-expanding piloboloid mutants ofPhycomyces blakesleeanus

The growth zone of the sporangiophore of a piloboloid mutant,pil, ofPhycomyces expands radially at an increased rate until the growth zone becomes nearly spherical, in sharp contrast to that of the wild-type sporangiophore which exhibits longitudinal elongation only and is conical. The rotation of thepil sporangiophore reverses its direction from clockwise (CW) to counterclockwise (CCW) during the period of increased radial expansion, and the CCW rotation continues as long as does the radial expansion. The direction of rotation and the time of reversal are correlated with the relative rates of cell-wall expansion in the longitudinal and transverse directions. The CCW rotation of the sporangiophore of this mutant can be explained by the behavior of the microfibrils, as previously proposed to explain the rotation of the wild-type sporangiophore.Abbreviations CW clockwise - CCW counterclockwise — both as viewed from above     

Development of Sporangiophores of Peronospora parasitica (Pers. ex Fr.) Fr.

The morphology of developing sporangiophores of Peronosporaparasitica from wallflower is described, and morphogenesis maybe divided into the following five stages: the sporangiophoreprimordium, unbranched sporangiophore, branched sporangiophore,spore formation and maturation, and formation of the cross wall.The growth of individual sporangiophores in a humidity chamberwas followed under the microscope, and increase in height andincrease in volume measured. The greatest increase in volumewas during spore formation, when the sporangiophore volume mightquadruple within an hour.     

Pressure probe study of the water relations of Phycomyces blakesleeanus sporangiophores

The physical characteristics which govern the water relations of the giant-celled sporangiophore of Phycomyces blakesleeanus were measured with the pressure probe technique and with nanoliter osmometry. These properties are important because they govern water uptake associated with cell growth and because they may influence expansion of the sporangiophore wall. Turgor pressure ranged from 1.1 to 6.6 bars (mean = 4.1 bars), and was the same for stage I and stage IV sporangiophores. Sporangiophore osmotic pressure averaged 11.5 bars. From the difference between cell osmotic pressure and turgor pressure, the average water potential of the sporangiophore was calculated to be about -7.4 bars. When sporangiophores were submerged under water, turgor remained nearly constant. We propose that the low cell turgor pressure is due to solutes in the cell wall solution, i.e., between the cuticle and the plasma membrane. Membrane hydraulic conductivity averaged 4.6 x 10(-6) cm s-1 bar-1, and was significantly greater in stage I sporangiophores than in stage IV sporangiophores. Contrary to previous reports, the sporangiophore is separated from the supporting mycelium by septa which prevent bulk volume flow between the two regions. The presence of a wall compartment between the cuticle and the plasma membrane results in anomalous osmosis during pressure clamp measurements. This behavior arises because of changes in solute concentration as water moves into or out of the wall compartment surrounding the sporangiophore. Theoretical analysis shows how the equations governing transient water flow are altered by the characteristics of the cell wall compartment.     

First Report of Peronospora belbahrii on Sweet Basil in Baja California Sur,México

In Baja California Sur, Mexico, a foliar disease occurred on sweet basil which seriously affected its quality and yield. The most common symptoms were yellowing and necrosis on leaves, caused by a downy mycelium growth on the lower leaf surface. Symptomatic leaves from two sampling sites were collected for morphological studies and molecular analysis of pathogen DNA. Based on morphological characteristics (sporangiophore size of 240–530 × 7–11 μm, branches of 5–8 order and a sporangia size of 27–31 × 21–25 μm) and molecular analysis (the GenBank blast of the PCR assays showed unique rDNA sequence data with 99% similarity to P. belbahrii), the pathogen was identified as Peronospora belbahrii, the causal agent of basil downy mildew. This is the first report of P. belbahrii affecting sweet basil in Mexico.     

The gravireceptor of Phycomyces. Its development following gravity exposure

The gravitropism of a mature stage IV Phycomyces sporangiophore has a shorter and more uniform latency if the sporangiophore is exposed horizontally to gravity during its earlier development (stage II and stage III). This early exposure to an altered gravitational orientation causes the sporangiophore to develop a gravireceptor as it matures to stage IV and resumes elongation. A technique has been developed to observe the spatial relationship between the vacuole and the protoplasm of a living sporangiophore and to show the reorganization caused by this exposure to altered gravity. Possible gravireceptor mechanisms are discussed.