Fertile organs and in situ spores of a new dipteridaceous fern Hausmannia sinensis from the Jurassic of northern China

As a representative fossil member of the dipteridaceous fern, genus Hausmannia was reported worldwide from the Mesozoic strata; however, little is known about the fertile structures, including sporangia and in situ spores, of this genus. In this study, a new species Hausmannia sinensis was identified from the Middle Jurassic of Nei Mongol (Inner Mongolia), northern China. The specimens are compressions and are well preserved with details of sporangia and in situ spores. The leaf laminae are broadly fan-shaped, with an almost entire margin. Primary and lateral veins dichotomously branch to form square or polygonal meshes. Each ultimate mesh bears one to two circular sori of 0.4 mm in diameter. Sori are exindusiate; each sorus contains three to six round to ovoid sporangia. The annulus is developed and oblique, with stomial region present in proximal position. Spores are trilete, circular to oval in shape. Both proximal and distal surfaces are covered with baculate to subverrucate sculptures. Spores range from 20 to 30 μm in diameter (average 28 μm), and are comparable to the dispersed genera Baculatisporites Thomas and Pflug and Apiculatisporis Potonié and Kremp. Hausmannia sinensis represents the first compression species of genus Hausmannia form Eurasia, which shows the combination of well-preserved sori, sporangia, annuli and in situ spore characters, and is therefore helpful for further understanding the diversity and evolution of the Dipteridaceae fern lineage through time.     

A Strategy for the Proliferation of Ulva prolifera,Main Causative Species of Green Tides,with Formation of Sporangia by Fragmentation

Ulva prolifera, a common green seaweed, is one of the causative species of green tides that occurred frequently along the shores of Qingdao in 2008 and had detrimental effects on the preparations for the 2008 Beijing Olympic Games sailing competition, since more than 30 percent of the area of the games was invaded. In view of the rapid accumulation of the vast biomass of floating U. prolifera in green tides, we investigated the formation of sporangia in disks of different diameters excised from U. prolifera, changes of the photosynthetic properties of cells during sporangia formation, and development of spores. The results suggested that disks less than 1.00 mm in diameter were optimal for the formation of sporangia, but there was a small amount of spore release in these. The highest percentage of area of spore release occurred in disks that were 2.50 mm in diameter. In contrast, sporangia were formed only at the cut edges of larger disks (3.00 mm, 3.50 mm, and 4.00 mm in diameter). Additionally, the majority of spores liberated from the disks appeared vigorous and developed successfully into new individuals. These results implied that fragments of the appropriate size from the U. prolifera thalli broken by a variety of factors via producing spores gave rise to the rapid proliferation of the seaweed under field conditions, which may be one of the most important factors to the rapid accumulation of the vast biomass of U. prolifera in the green tide that occurred in Qingdao, 2008.     

Germination and outgrowth of Bacillus popilliae in hemolymph slide mounts

Cabbage looper hemolymph induced rapid germination and outgrowth of spores of Bacillus popilliae. Spores germinated within sporangia but outgrowth occurred from free released spores as well as from spores retained in sporangia. With 37°C, an alkaline pH, and tyrosinase, outgrowth resulted in 1 hr. Of six strains of milky disease bacteria tested, hemolymph mediated germination and outgrowth of only those which are infective perorally for European chafer larvae, indicating a potential use as a screening tool to assess virulence for the chafer.     

A new genus for isolated bivalved sporangia with thickened margins from the Lower Devonian of the Welsh Borderland

A new taxon Sporathylacium salopense gen. et sp. nov . is based on small isolated coalified sporangia from the Lower Devonian (Lochkovian: micrornatus—newportensis spore zone) from the Welsh Borderland. The sporangia have two equal valves with multi-layered walls and thickened borders, and contain trilete crassitate, non-curvaturate isospores that are completely covered by a microgranular ornament with possible distal verrucate/murornate structures. They differ from zosterophyll sporangia in details of the presumed dehiscence zone extending around the entire free convex margin, particularly in the presence of a wedge of amorphous material between the valves, and in spore characters. Absence of any information relating to water-conducting cells prevents further assignment within the embryophytes. Spherical bodies associated with spores and a resilient sporangial lining are compared with similar structures in extant free-sporing plants and with Ubisch bodies. The mode of sporangial dehiscence involving anatomical modifications of the valve margins and the novel wedge of tissue which connects them remains speculative.     

Fossil plants with spores in the sporangia from the Upper Devonian (Frasnian) deposits of northern Timan

Fossil plants from the Upper Devonian (Frasnian) of northern Timan are studied. The sporangia contain well-preserved spores, which were studied in transmitted light using a scanning electron microscope. The genus Gutzeitia S. Snigirevsky, gen. nov. is established. Macroremains and in situ spores of G. timanica (Petros.) S. Snig., comb. nov. and ?Cephalopteris mirabilis (Nath.) Nath. are described. Microspores in Dimeripteris gracilis Schmalh. are identified, and microspores and megaspores in ?Cephalopteris mirabilis are studied for the first time.     

Genetic exchanges in the macrocysts of Dictyostelium discoideum.

Crosses were made between strains of Dictyostelium discoideum involving two drug resistance markers and the mating-type locus. Over 6000 progeny from 263 individual germinated macrocysts from four single-factor crosses, five two-factor crosses and one three-factor cross were characterized. In most cases the progeny from a single macrocyst were of one genotype, although in the population of macrocysts from any two-factor cross all possible parental and recombinant genotypes were recovered. There was no evidence of linkage between any of the markers examined. No selection against progeny carrying the methanol or the cycloheximide resistance markers was found in two-factor crosses, but selection against progeny carrying both resistance markers was found in the three-factor cross. Germination of macrocysts in all crosses was poor, only once exceeding 2.5% of the total macrocyst population. A variety of crosses and back-crosses with different parental strains indicated that germination might be influenced by both extrinsic (environmental) and multiple genetic factors. About 10% of the macrocysts yielded progeny spores that were ambivalent in their mating reactions. After extensive recloning these populations could be resolved to the normal matA (formerly A1) and mata (formerly A2) mating-types and might therefore have represented aneuploids. The results obtained with D. discoideum macrocysts differ from those obtained with other cellular slime moulds--Dictyostelium mucoroides, Dictyostelium giganteum and Polysphondylium pallidum--and are reminiscent of the results reported for germinated zygospores of Phycomyces blakesleeanus.     

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。     

Phycomycetes parasitizing the ovaries of blackflies (simuliidae)

The developmental stages of the fungus in the ovary and freshwater are discussed. Based on the evidence to date the simuliid host is infected in the early larval instars. Parasitism results in a destruction of the ovarian tissues with no or few eggs produced. The fungus replaces the ovarian tissue and produces massive numbers of spores which are released by the female fly at the time of oviposition. After oviposition, infected flies do not seek a blood meal. Longevity of the host does not appear to be affected by the presence of the fungus. The spores released by the fly during oviposition did not withstand desiccation and did not develop on the artificial media tested; development occurs only in water. Development of sporangia takes 5 to 7 days at 4°C, and 2 to 3 days at temperatures above 10°C. The developmental process in spores from S. verecundum was followed from the formation of sporangia to the opening of discharge tubes which zoospores were presumed to be released but not observed.     

TETRAXYLOPTERIS SCHMIDTII: ITS FERTILE PARTS AND ITS RELATIONSHIPS WITHIN THE ANEUROPHYTALES

The fertile branching system of Tetraxylopteris is composed of successive “nodes” bearing opposite and decussately arranged, upcurved sporangial complexes. By means of the transfer technique the morphology of the sporangial complex was revealed. It consists of a main stalk which dichotomizes twice producing four major branches. Each of the four branches is further subdivided three times, the subdivisions being arranged alternately and pinnately. The ultimate divisions bear the sporangia singly and terminally. The sporangial complexes decrease in size distally and are more tightly curved at the apex. The sporangia are oblong-oval with an acute apex. The spores are identical to the dispersed spore taxon Rhabdosporites langii, Richardson. They are spherical, trilete and pseudosaccate with a fine granular ornament on the pseudosaccus. They are 75–176 μ in diameter and show developmental stages from young tetrads to separated, fully mature spores depending on the age of the sporangium from which they were obtained. This is the first account of spores in sporangia of Tetraxylopteris. The diagnosis of the genus and species are emended to include the new information and the order Aneurophytales is redefined.     

Secondary Sporangium Formation in Phytophthora Palmivora (Butl.) Butl

Very few sporangia of Phytophthora palmivora germinated directlyand produced secondary sporangia in distilled water and in solutionsof amino acids and carbohydrates at 30 °C. Although 1.0per cent (w / v) peptone and yeast-extract stimulated a highpercentage of germination by formation of germ tubes, less than1.0 per cent of the germinated sporangia produced secondarysporangia. Secondary sporangium formation was induced by transferringgerminated primary sporangia from a nutrient medium of sufficientlyhigh concentration to either distilled water or dilute solutionsof organic and inorganic compounds immediately after emergenceof the germ tubes. The percentage of germinated sporangia formingsecondary sporangia was influenced by both the nature and concentrationof the medium into which they were transferred. The secondarysporangia were significantly smaller than the primary sporangia. Phytophthora palmivora, germination, sporangium, Theobroma cacao L., cocoa     

Development of the Mycetozoan Echinosteliopsis oligospora*

SYNOPSIS. The mycetozoan genus Echinosteliopsis, resembling the myxomycete Echinostelium in some of its features, is described. The single species, E. oligospora Reinhardt & Olive, forms small sporocarps which consist of a basal disk, stalk and a sporangium with only 1–8 spores. Spores form progressively, not simultaneously, by segmentation. The spores germinate to release non-flagellate amebae which, in liquid, assume a characteristic broad, fan shape. Each ameba has one or more nuclei. The nucleus is distinctive because of refractile, globular to elongate peripheral bodies which cytochemical tests indicate to be primarily RNA. At the time of nuclear division the characteristic RNA bodies disappear and, as observed with the phase microscope and in stained preparations, optically dense material accumulates in the middle area of the nucleus. Threads, either a spindle or actual chromatin, can be seen attached to the nuclear membrane. The threads separate to opposite poles as the nucleus elongates. During this division process the nuclear membrane apparently remains intact. Synchronous binucleate divisions, as well as a tripolar nuclear division, have been observed. Uninucleate and synchronous binucleate divisions may or may not be followed by cytokinesis. The absence of cell division after nuclear division leads to the production of cells with varying numbers of nuclei. Nuclear divisions in early sporangial stages and in spores have not been observed. The spores are uni- to multinucleate. In 8-spored sporangia and in most 4-spored sporangia there is a characteristic small “stalk spore” at the apex of the stalk. The stalk spore germinates slowly, if at all, but the larger spores germinate readily. No evidence of a sexual process has been found.     

Influence of nitrogen and phosphorus on polyphosphate accumulation in Gigaspora margarita during spore germination

Polyphosphate (polyP) is the form in which phosphorus (P) is transferred from extraradical hyphae into arbuscles in the symbiotic stage of arbuscular mycorrhizal fungi. However, polyP dynamics in the presymbiotic stage are less understood. In this study, we aimed to investigate polyP accumulation in Gigaspora margarita as influenced by nitrogen (N) and/or P supply during germination. Spores of G. margarita were incubated on medium with or without P or N addition. PolyP content in the fungal tissue was monitored using a polyP kinase/luciferase system, and polyP synthetic activity was determined with ³²P labeling. The results showed that both N and P were necessary for polyP accumulation in germ tubes. Nitrate increased the polyP content in germ tubes, but ammonium did not. Along with germination, polyP content decreased in spores, but increased in germ tubes. ³²P labeling indicated that polyP synthetic activity increased in germ tubes along with germination, but was negligible in spores. Our results suggest that, in the presymbiotic stage of G. margarita, uptake of environmental N and P increases polyP content in germ tubes, and that polyP synthesis occurs mainly therein, leading to polyP accumulation. The possible mechanism of transfer of polyP from spores to hyphae remains to be elucidated.     

Davallia (Polypodiales: Davalliaceae) macrofossils from Early Miocene Otago (New Zealand) with in situ spores

Fossil fern fronds referable to the extant fern genus Davallia (Polypodiales: Davalliaceae) bearing sporangia with in situ spores are described from the Early Miocene Foulden Maar diatomite deposit, Otago, New Zealand. The fronds are the first published Southern Hemisphere macrofossil record for the family and provide valuable palaeoclimate data supporting warm conditions in Early Miocene New Zealand. The matching of Davallia fronds to the form spore taxon Polypodiisporites radiatus shows that the genus has had a long, apparently continuous history throughout late Cenozoic New Zealand.     

Degree of Completion of 3′-Terminus of Transfer Ribonucleic Acids of Bacillus subtilis 168 at Various Developmental Stages and Asporogenous Mutants

Transfer ribonucleic acids from sporulating cells, spores, sporangia, or stationary-phase asporogenous mutants of Bacillus subtilis all showed a deficiency in the 3′-terminal adenosine moiety.     

Germ Cell Transplantation Using Sexually Competent Fish: An Approach for Rapid Propagation of Endangered and Valuable Germlines

The transplantation of germ cells into adult recipient gonads is a tool with wide applications in animal breeding and conservation of valuable and/or endangered species; it also provides a means for basic studies involving germ cell (GC) proliferation and differentiation. Here we describe the establishment of a working model for xenogeneic germ cell transplantation (GCT) in sexually competent fish. Spermatogonial cells isolated from juveniles of one species, the pejerrey Odontesthes bonariensis (Atherinopsidae), were surgically transplanted into the gonads of sexually mature Patagonian pejerrey O. hatcheri, which have been partially depleted of endogenous GCs by a combination of Busulfan (40 mg/kg) and high water temperature (25°C) treatments. The observation of the donor cells'' behavior showed that transplanted spermatogonial cells were able to recolonize the recipients'' gonads and resume spermatogenesis within 6 months from the GCT. The presence of donor-derived gametes was confirmed by PCR in 20% of the surrogate O. hatcheri fathers at 6 months and crosses with O. bonariensis mothers produced hybrids and pure O. bonariensis, with donor-derived germline transmission rates of 1.2–13.3%. These findings indicate that transplantation of spermatogonial cells into sexually competent fish can shorten considerably the production time of donor-derived gametes and offspring and could play a vital role in germline conservation and propagation of valued and/or endangered fish species.     

Exceptional preservation in Lower Devonian coalified fossils from the Welsh Borderland: a new genus based on reniform sporangia lacking thickened borders

Reniform sporangia, comprising two equal valves and containing retusoid spores, recovered from Lower Old Red Sandstone strata of Devonian age (micrornatus-newportensis Spore Biozone: lower Gedinnian lower Lochkovian) on North Brown Clee Hill in the Welsh Borderland are placed in Resilitheca salopensis gen. et sp. nov. Conventional compression fossils from Targrove, Ludlow of fertile axes showing isotomous branching with limited overtopping are considered conspecific because the terminal reniform sporangia contain the same spores. Spore ultrastructure is described using scanning and transmission electron microscopy. Sections show faint traces of lamellae. Particles associated with spores and sporangium wall are compared with the globules of pteridophytes and Ubisch bodies of angiosperms, and related to the development of the sporangium. The new plants are compared with Cooksonia caledonica Edwards known only from impressions, and with Renalia Gensel showing far more pronounced pseudomonopodial branching.     

Two new species of Kladnostrobus nov. gen. and their spores from the Pennsylvanian of the Kladno-Rakovník Basin (Bolsovian, Czech Republic)

A new lycopsid family Kladnostrobaceae is proposed, based on the type of sporangia, their attachment by a pedicel and the type of reticulate spores enclosed. All these characteristics distinguish the Kladnostrobaceae from all other lycopsid families. A new lycopsid genus Kladnostrobus nov. gen., consisting of two new species Kladnostrobus clealii nov. sp. and Kladnostrobus psendae nov. sp., is described from the Kladno-Rakovník Basin (Lower Bolsovian) of the central and western Carboniferous continental basins of the Czech Republic. Helically arranged distal laminae and pedicels are relatively primitive, suggesting that Kladnostrobus may represent a new, primitive type of lycopsid cone produced by some unknown, probably arborescent lycopsid parent plant. Spores of Kladnostrobus are about 90-100 μm in diameter, and possess reticulate sculpture. The proximal contact area of spores is laevigate. In situ spores can resemble some dispersed species of the genera Convolutispora Hoffmeister, Staplin and Malloy, Camptotriletes (Naumova) Potonié and Kremp, Reticulatisporites (Ibrahim) Neves and mainly Dictyotriletes (Naumova) Smith and Buttterworth.     

HETEROTHALLISM AND HOMOTHALLISM IN TWO MYXOMYCETES

Collins , O'Neil Ray . (Queens Coll., New York City.) Heterothallism and homothallism in two Myxomycetes. Amer. Jour. Bot. 48(8): 674–683. Illus. 1961.—Single-spore studies of 2 Myxomycetes, Didymium iridis and Fuligo cinerea, revealed that the former is heterothallic and the latter is homothallic. In D. iridis, 256 single-spore isolations were made from sporangia which developed in mass-spore cultures. Of these, 101 germinated and 22 yielded plasmodia that later fructified in most cases. The remaining 79 single-spore cultures produced clones of myxamoebae and swarm cells only. When 18 of the 79 clones were mated in all possible combinations, plasmodia developed in a pattern which showed that the clones were either (+) or (–) with regard to mating type. Fructifications were readily obtained from these plasmodia. Fifty-three single spores of the F₁ generation were isolated. Of the 44 that germinated, 9 yielded plasmodia in monospore cultures, and 35 produced clones of myxamoebae and swarm cells only. Twenty-five of the F₁ clones were back-crossed with their parents. Results of the back crosses show that each F₁ clone is capable of yielding plasmodia with either the (+) or the (–) parent, never with both. When 14 of the F₁ clones were mated among themselves, a (+) and (–) mating type system was again revealed. Most of the 22 original single-spore cultures which produced plasmodia, later formed sporangia. From these sporangia, 88 spores were isolated. Seventy-two of these germinated and yielded large populations of swarm cells and myxamoebae, but none produced plasmodia. Twenty of the 72 clones were then mated among themselves. Some matings resulted in plasmodial formation, but the pattern was difficult to interpret. However, when these 20 clones were mated with known (+) and (–) clones, the results appear to be in keeping with a (+) and (–) mating type system. In F. cinerea, 219 single spores were isolated from aethalia derived from mass-spore cultures. Of these, 144 germinated and the same number yielded plasmodia. Fructifications were easily obtained from such plasmodia. Thirty-five second-generation single spores were isolated, of which 15 germinated and 15 yielded plasmodia. These results indicate that F. cinerea is homothallic.     

A diverse assemblage of early land plants from the Lower Devonian of the Welsh Borderland

FANNING, U., EDWARDS, D. & RICHARDSON, J. B., 1992. A diverse assemblage of early land plants from the Lower Devonian of the Welsh Borderland. Nine rhyniophytoid taxa are described from an early Gedinnian locality ( middle micromatus-newportensis spore Biozone) near Ludlow, England. They include Cooksonia pertoni, C. hemisphaerica, C. cambrensis, Tortilicaulis transwalliensis and three new taxa, Salopella marcensis sp. nov., Uskiella reticulata sp. nov. and Tarrantia salopensis gen. et sp. nov. Isolated sporangia of reniform shape, and those subtended by short lengths of axis, contain spores of Apiculiretusispora type and may belong to C. caledonica or Renalia . Morphologically distinctive forking, terminal sporangia lacking identifiable spores are not placed in a new taxon, because evidence based on in situ spores from elsewhere suggests they may belong to Salopella . Structures previously interpreted as clusters of sporangia of Yarravia- type are shown to be ± globular sporangia longitudinally split into valves. Sterile axes are dominated by smooth forms; although rare examples possess small enations. Tracheids have not been seen in axes of fertile specimens nor in sterile coalified compressions. A single pyrite permineralization contains tracheids of zosterophyll type. The assemblage demonstrates diversity among rhyniophytoids in the early Devonian and the existence of low vegetation 'alongside' the much larger zosterophyll dominated type.