PROBABLE ATTACHMENT OF THE DOLEROTHECA CAMPANULUM TO A MYELOXYLON-ALETHOPTERIS TYPE FROND

The discovery of pedunculate specimens of pollen organ Dolerotheca in close association with Myeloxylon-type pinnae and Alethopteris-type pinnules provides evidence for the reconstruction of a petrified medullosan frond and the attachment of the microsporangiate fructification. Specimens of Dolerotheca villosa and D. formosa from Middle and Upper Pennsylvanian age strata of North America are borne on slender peduncles with anatomical features and vascularization identical to those of some level in a Myeloxylon-Alethopteris-type frond. Reconstruction of the frond reveals a large, repeatedly dichotomising organ that bears penultimate pinnae and ultimate pinnules in a pinnate arrangement. Examination of pinnules on the surface of coal ball material indicates that they conform to the compression genus Alethopteris. Identical numbers and arrangement of vascular bundles together with identical anatomical features and multicellular hairs indicate that the Dolerotheca campanulum is borne in the position of a penultimate pinna. A reconstruction of the frond with a proposed polled organ attachment is included.     

HALLETHECA RETICULATUS GEN. ET SP. N.: A SYNANGIATE PENNSYLVANIAN PTERIDOSPERM POLLEN ORGAN

A new structurally preserved synangiate pollen organ is described from the upper Pennsylvanian (Mattoon Formation) of southeastern Illinois. The specimen of Halletheca reticulatus gen. et sp. nov. measures approximately 1.5 cm long by approximately 5.0 mm in diam, and consists of five elongate sporangial tubes equidistantly arranged around a solid central column, and embedded in a thin-walled ground tissue. The vascular system consists of five terete bundles characterized by scalariform tracheids. Sporangia are thick-walled and contain pollen of the Monoletes-type. Ultrastructural studies of the pollen grain wall show it to consist of a uniform network of muri which branch and re-unite to form small lumina. A comparison of the ultrastructure of the pollen grain wall of the new fructification is made with the wall organization found in similar pollen of Dolerotheca. Relationships between the new taxon and other presumed seed fern pollen organs differing in preservation mode are discussed.     

DIMENSIONAL CORRELATIONS IN DEVELOPING SELAGINELLA SPORANGIA

With length of sporangia as a developmental index, the growth relationships of sporangia during differentiation were studied in strobili of Selaginella bigelovii. The strobili usually contain two rows of megasporangia and two rows of microsporangia with a mega- opposite a microsporangium at each node. Prior to the sporocyte stage a sporangium in a megasporangiate row is larger and elongates more rapidly than a sporangium opposite it at the same node in a microsporangiate row. The number of sporogenous cells is similar in sporangia of the same length from both rows until cell multiplication ceases in sporangia of the megasporangiate row, while it continues in sporangia of the same size in the microsporangiate row. The observed growth differences between sporangia of the micro- and megasporangiate rows are interpreted as events in the differentiation of two sporangial types.     

STEWARTIOTHECA GEN. N. AND THE NATURE AND ORIGIN OF COMPLEX PERMINERALIZED MEDULLOSAN POLLEN ORGANS

Stewartiotheca gen. n. is a bell-shaped, unisynangiate pollen organ with eccentric radial symmetry and a single series of about 80 pollen sacs. Infoldings that vary in depth occur circumferentially and extend from the periphery to a point off center. This position also marks the location of a sclerenchyma column (proximally) and a sclerenchyma-lined, conical hollow (distally) that opens onto the distal face of the organ. Plates of ground parenchyma extend inward from the outer covering of the organ at locations of infoldings, while similar plates with sclerenchyma strands occur between these locations. Pre-pollen of Monoletes type was released through distal longitudinal slitlike openings of the pollen sac faces toward the sclerenchymatous ground tissue plates. Vascular bundles entering the organ undergo repeated dichotomies, and lead to numerous bundles both in the cover (one per sac for those sacs that abut directly on cover tissue) and internally (one per pair of pollen sacs that lie opposite one another across the location of an infolding). The most complex permineralized medullosan pollen organs Sullitheca, Stewartiotheca, and Dolerotheca are considered to have evolved from a similar type of cup-shaped organ with a single ring of pollen sacs, broadly open distally, and with a central hollow. Circumferential infoldings of one organ of this type were involved in the origin of both Stewartiotheca and Sullitheca, while four similar organs, each showing infoldings non-circumferentially, fused to produce the Dolerotheca type organ (exemplified by D. formosa), a compound synangium.     

PHILLIPOPTERIS GEN. NOV.—ANATOMICALLY PRESERVED SPORANGIAL FRUCTIFICATIONS FROM THE UPPER PENNSYLVANIAN OF THE APPALACHIAN BASIN

The discovery of a new type of sporangial fructification in coal balls from the Upper Pennsylvanian of Ohio provides the basis for describing Phillipopteris globiformis gen. et sp. nov. Sporangia are borne terminally on up to two orders of branching axes. Penultimate axes branch pinnately to produce irregularly branched ultimate axes. Sporangial wall cells are of a single type and show no specialization for dehiscence. Spores are radial and trilete, and reminiscent of the sporae dispersae genus Dictyotriletes. Phillipopteris increases our knowledge of diversity among fernlike plants from the late Paleozoic, and shares several features with Sclerocelyphus Mamay.     

SPORES OF BOTRYOPTERIS GLOBOSA AND BOTRYOPTERIS AMERICANA FROM THE PENNSYLVANIAN

A study of spores from fertile pinnae of Botryopteris from middle and upper Pennsylvanian coal balls from Iowa, Illinois, and Kansas indicates that there are two distinct species, Botryopteris globosa and B. americana. The organization and attachments of fertile pinnae and the sporangial morphology and dimorphism are identical in the two species. Data are given on fertile pinnae dimensions, attachments of six fertile pinnae, spore counts from individual sporangia, and spore morphology. The ornamentation of B. americana spores is verrucate to rugulate with verrucae fusing to a variable extent to form bars and convolute ridges; B. globosa spores are vermiculate or fossulate to densely rugulate with scattered verrucae. Comparisons are made with B. forensis and a re-interpretation of the spore forms of B. forensis is suggested.     

Evolution of Spore Release Mechanisms in the Saprolegniaceae (Oomycetes): Evidence from a Phylogenetic Analysis of Internal Transcribed Spacer Sequences

Classical studies on spore release within the Saprolegniaceae (Oomycetes) led to the proposition that different mechanisms of sporangial emptying represent steps in an evolutionary transition series. We have reevaluated this idea in a phylogenetic framework using internal transcribed spacer sequences of four genera. These data were compared with the response to osmotic stress exhibited by each taxon.Saprolegniaemerges as the most basal genus, sister toAchlya, Thraustotheca,andDictyuchus. AchlyaandThraustothecaare most closely related, whileDictyuchusappears to have evolved along a separate evolutionary lineage. The resulting phylogenetic framework is consistent with the idea that the mechanism of sporangial emptying exhibited bySaprolegniarepresents the plesiomorphic condition from which the other mechanisms were derived independently. These alternative mechanisms of spore release may have resulted from a small number of mutations that inhibited axonemal development and altered the temporal and spatial expression of lytic enzymes that degrade the sporangial wall.     

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.     

红毛菜丝状体核分裂研究

选择具异型世代交替的福建人工栽培的红毛菜为研究材料,对红毛菜丝状体世代的丝状藻丝及孢子囊枝等阶段进行了较系统的核分裂观察研究,探讨红毛菜核分裂特征.结果显示:红毛菜营养藻丝和孢子囊枝细胞均为二倍体细胞,2n=8,其核分裂显示为有丝分裂的过程;同时,丝状体阶段细胞核分裂至前期末均会出现同源染色体配对现象,显示有丝分裂同源染色体配对行为是红毛菜丝状体核分裂的一个重要特征.     

Chansitheca wudaensis (Gleicheniaceae,fern) from the early Permian Wuda Tuff Flora,Inner Mongolia

A large number of specimens of Chansitheca wudaensis Deng, Sun et Li from the early Permian Wuda Tuff Flora allow an emendation of this species. Characters of the sporangial structure and in situ spores are examined for the first time. Sori are arranged on lateral veins of pinnule lobes, and are 0.61–0.69 mm long and 0.35–0.41 mm wide. Sporangia are sessile and surrounded by an annulus, which is composed of two rows of oblong thick-walled cells. Trilete, smooth in situ spores have diameters of 21.05–26.31 μm. Features of the reproductive organ indicate that this species is similar to Szea Yao et Taylor and some species of Oligocarpia Goeppert and belongs to the Gleicheniaceae. Based on a taphonomical analysis, C. wudaensis was an herbaceous element of the groundcover in the peat-forming coal swamp.     

A NEW PTERIDOSPERM MALE FRUCTIFICATION FROM THE MIDDLE PENNSYLVANIAN OF ILLINOIS

Rhetinotheca tetrasolenata gen. et sp. n. is described from a Herrin #6 coal ball from Illinois. It consists of an ellipsoidal cluster of small synangia bearing spores of the Monoletes type. Although the synangia are partially connected to each other by sparse sterile tissue, evidence indicates that the synangia are immature, and it is presumed that they separated and spread apart at maturity. A small portion of a protostelic axis is present near the center of the cluster. Individual synangia consistently contain four sporangial tubes and measure 2.0–3.6 mm long by 0.7–1.2 mm in diam. A conspicuous central columella is present. When compared with compression forms, Rhetinotheca tetrasolenata compares most favorably with Aulacotheca iowensis. On this basis, arguments are advanced disputing the classical concept of whittleseyan fructifications. It is contended that none of them possessed a hollow central cavity as depicted in most reconstructions.     

Metabolite changes during the life history of Porphyra haitanensis

Plant metabolomics is essentially the comprehensive analysis of complex metabolites of plant extracts. Metabolic fingerprinting is an important part of plant metabolomics research. In this study, metabolic fingerprinting of different stages of the life history of the red alga Porphyra haitanensis was performed. The stages included conchocelis filaments, sporangial branchlets, conchosporangia, discharged conchospores and conchosporangial branchlets after conchospore discharge. Metabolite extracts were analysed with ultra‐performance liquid chromatography coupled with electrospray ionisation quadrupole‐time of flight mass spectrometry. Analyses profiles were subjected to principal components analysis and orthogonal projection to latent structures discriminant analysis using the SIMCA‐P software for biomarker selection and identification. Based on the MS/MS spectra and data from the literature, potential biomarkers, mainly of phosphatidylcholine and lysophosphatidylcholine, were identified. Identification of these biomarkers suggested that plasma membrane phospholipids underwent major changes during the life history of P. haitanensis. The levels of phosphatidylcholine and lysophosphatidylcholine increased in sporangial branchlets and decreased in discharged conchospores. Moreover, levels of sphingaine (d18:0) decreased in sporangial branchlets and increased in discharged conchospores, which indicates that membrane lipids were increasingly synthesised as energy storage in sporangial branchlets, while energy was consumed in sporangial branchlets to discharged conchospores. A metabolomic study of different growth phases of P. haitanensis will enhance our understanding of its physiology and ecology.     

A NEW BOWMANITEAN FRUCTIFICATION FROM THE PENNSYLVANIAN OF KANSAS

Mamay , Sergius H. (U. S. Geological Survey, Washington, D. C.) A new bowmanitean fructification from the Pennsylvania of Kansas. Amer. Jour. Bot. 46(7): 530–536. Illus. 1959.—A new sphenophyllaceous fructification, Bowmanites moorei sp. nov., is described on the basis of coal ball petrifactions from the Fleming coal in southeastern Kansas. One of the simplest species of Bowmanites, B. moorei has only 3 sporophylls in a whorl. Each sporophyll has 3 lobes, the median one fertile, the 2 lateral ones sterile. Each fertile lobe subtends 2 sporangia, resulting in 6 sporangia in a whorl. The sporangia are inverted, being distally attached to separate sporangiophores that arise in pairs, in axillary positions. The sporangial epidermis and epidermis of the lower surfaces of the sporangiophores are characterized by relatively large, thick-walled cells. The spores are small, spherical, and trilete, without distinctive ornamentation of the exine. B. moorei adds to the morphological variation known in Bowmanites, but contributes little toward a phylogenetic interpretation of this morphologically complex genus.     

BARINOPHYTON CITRULLIFORME (BARINOPHYTALES INCERTAE SEDIS,BARINOPHYTACEAE) FROM THE UPPER DEVONIAN OF PENNSYLVANIA

Barinophyton citrulliforme is definitely proven to be a tracheophyte. The vascular cylinder of the main axis is an exarch protostele composed of tracheids having a continuous secondary wall folded into protrusions into the cell lumen. These protrusions delineate the position of annular thickenings which were deposited earlier than the continuous secondary wall. Between successive protrusions, the later-deposited secondary wall is interrupted by minute pitlike structures. It is suggested that the secondary walls of the tracheids were laid down in a two-phase depositional sequence. The fertile system of B. citrulliforme consists of a main axis bearing spirally arranged strobili. The strobilus consists of an axis that bears two alternate rows of sporangiferous appendages. The sporangiferous appendages are borne laterally along the strobilar axis and recurve abaxially around the axis. The sporangia are attached along the inside curve of the appendages, one sporangium per appendage, each containing both microspores and megaspores. This species thus exhibits sporangial heterospory which is considered to be an adaptation to an aquatic habit and the sporangia are considered to be functional analogs of the sporocarps of Marsilea. The interpretation of the strobilus is morphologically identical to Ananiev's interpretation of the strobilus of Pectinophyton bipectinatum; consequently P. bipectinatum is here transferred to Barinophyton as B. robustius comb. nov.     

Sporangila autolysis in Clostridium perfringens type A

The autolytic system functioning in the release of mature spores and enterotoxin from sporangia of Clostridium prefringens was partially characterized. After sporangial autolysis in buffer, the supernatant fluid of the suspension contained autolysin active against purified sporangial walls. The autolysin was most active at pH 8 and 37°C, in the presence of Co²⁺ (0.3 · 10⁻³ M CoCl₂) and trypsin (48 μg/ml). Sodium dodecyl sulfate-treated sporangial walls further extracted with trichloroacetic acid to remove teichoic acid were a better enzyme substrate than walls treated only with sodium dodecyl sulfate. N-Acetylmuramyl-l-alanine amidase activity which released N-terminal alanine, and endopeptidase activity which hydrolysed the d-alanyl-glycine linkage liberating N-terminal glycine and C-terminal alanine, were both functional at pH 8. It is not known if one or two enzyme are involved. Autolysin appeared in cells as early as 2 h after inoculation into sporulation medium. Two asporogenic Stage 0 mutants grown in sporulation medium also produced autolysin identical in mode of action to that of the sporogenic wild type. Although the active cellular autolysin concentration subsequently decreased as cells sporilated, the walls of 8-h-old sporangia containing refractile heat-resistant spores were more susceptible to digestion by autolysin, than those of 2-, 4-, or 6-h-old cells grown in sporulation medium or of 4- or 14-h vegetative cells from growth medium. The results suggest that a progressive change may occur in the structure of the sporangial wall during spore morphogenesis, thus increasing its susceptibility to autolysis.     

FERAXOTHECA GEN. N., A LYGINOPTERID POLLEN ORGAN FROM THE PENNSYLVANIAN OF NORTH AMERICA

The pollen organ Feraxotheca gen. n. is described from Pennsylvanian age coal balls from the Lewis Creek, Kentucky, locality. The fructifications consist of bilaterally symmetrical synangia composed of a basal pad supporting elongate sporangia that are laterally appressed for the entire length of the sporangial cavities. Sporangial tips extend over the center of the synangium and delimit a small open area, while the bases arise from a parenchymatous cushion that is bounded by short tracheid-like cells. Each synangium is borne on the surface of an expanded pinna tip and is surrounded by a small amount of laminar tissue that envelopes the base of the synangium. Ultimate pinnae are rectangular in transverse section, possess an elliptical vascular bundle surrounded by canals containing a yellow froth-like substance, and have a cortex of elongate cells that radiate from the center of the axis. Sporangia contain small (40–64 μm), radial, trilete spores ornamented by regularly spaced coni or blunt tipped grana. Feraxotheca is compared with the compression genus Crossotheca and some new ideas are advanced concerning the morphology of this compression genus. The obvious differences between Feraxotheca and other lyginopterid pollen organs strongly suggests that the Lyginopteridaceae, as it is currently interpreted, is an unnatural family.     

Exploiting medicinal plants and phylloplane microflora for the management of grapevine downy mildew

Abstract

Grapevine downy mildew is the most devastating disease throughout the world causing huge monetary losses. Twenty medicinal plant extracts and six phylloplane microfloras were evaluated for their efficacy against sporangial germination of grapevine downy mildew pathogen Plasmopara viticola in vitro. The results revealed that the Neem Seed Kernel Extract (NSKE) at 5% significantly inhibited the sporangial germination (75.36%) of P. viticola. Among the phylloplane microflora Pseudomonas fluorescens was highly effective in reducing the sporangial germination (64.26%). Post inoculation spraying of NSKE (5%) and P. fluorescens (0.2%) effectively inhibited the disease development in the greenhouse. Three sprays with NSKE (5%) and phylloplane P. fluorescens (0.2%): first spray after initial appearance of disease and the second and third at 10 day intervals were found to be promising in reducing disease incidence in the field.     

DEVELOPMENT OF ENDOPHYTIC FRANKIA SPORANGIA IN FIELD- AND LABORATORY-GROWN NODULES OF COMPTONIA PEREGRINA AND MYRICA GALE

Field-collected nodules of Comptonia peregrina (L.) Coult. and Myrica gale L. (Myricaceae), infected by the nitrogen-fixing actinomycete Frankia sp., were of two types: those that lacked sporangia entirely, designated spore(-), and those that showed extensive sporangial development, designated spore(+). In spore(+) nodules of C. peregrina, sporangia began to develop after the differentiation of endophytic vesicles and the concomitant onset of nitrogenase activity. At the onset of sporangial differentiation, infected host cells appeared healthy. However, endophytic vesicles and host cell cytoplasm and nuclei began to senesce rapidly as sporangia developed. Staining of sectioned material with the fluorescent stain Calcofluor White suggested that vesicles, hyphae and young sporangia were enclosed within a host-derived encapsulation layer, but mature sporangia were no longer encapsulated. In both C. peregrina and M. gale, vesicles were more short-lived in spore(+) than in spore(-) nodules. Field-collected spore(+) M. gale nodules exhibited a pronounced seasonality of sporangial formation. Sporangia began to differentiate in June, after the formation of vesicles and became more prominent in late summer. Inter- and intraspecific cross-inoculations suggest that the ability to form sporangia in the symbiotic state is controlled by endophytic strain type rather than host genotype or host/endophyte combination. The host may, however, influence the number and seasonal appearance of sporangia formed.     

THE ANATOMY AND THREE-DIMENSIONAL MORPHOLOGY OF ANNULARIA HOSKINSII SP. N.

Foliage attached to calamitean shoots is described from coal ball petrifactions of Middle and Late Pennsylvanian age. Leaves correspond to the compression-impression genus Annularia and thus represent the first attached members of this genus to be recognized as petrifactions. Individual leaves contain a single unbranched vascular bundle flanked by wide lateral laminar areas which occupy more than half the leaf cross sectional area. Stomata are confined to broad bands within concave furrows which parallel the vascular bundle on the abaxial leaf surface. Epidermal cells within these furrows are in rows aligned obliquely to the leaf axis, and the rows angle outward at a slight angle towards the leaf margin. Convolutions of the leaf-bearing axes result from nodal diaphragms which are oblique to the shoot axis. Whorled leaves apparently radiate outward in the plane of each obliquely positioned nodal diaphragm. This petrified material helps explain the apparent flattening of entire nodal diaphragms and leaf whorls within the same plane as seen in compression specimens. Annularia hoskinsii sp. n. is proposed, and the systematic position of structurally preserved Annularia foliage relative to the genus Dicalamophyllum is discussed.