scholarly journals II. On the structure and life-history of Entyloma Ranunculi (bonorden)

1887 ◽  
Vol 41 (246-250) ◽  
pp. 318-318
Keyword(s):  
Life History ◽  
Middle Lamella ◽  
White Powder ◽  
Resting Spores ◽  
History Of ◽  
Open Country

The author found plants of Ranunculus Ficaria , the leaves of which were all spotted with white patches; the white patches spread from leaf to leaf, and the disease assumed the nature of an epidemic The rise, progress, and climax .of the disease were observed both on isolated plants and m the open country, and the nature of the lesions in the leaves was made out. Evidence was found to support the view that some plants succumb more rapidly; this evidence was tested, and the circumstances to which the differences are due explained. The white disease-spots contain the extremely delicate mycelium of Entyloma Ranunculi , and the. resting-spores of this fungus (one of the Ustilagineæ) were observed on it. The mycelium is intercellular, and makes its way in the middle lamella between contiguous cells. The white powder on the outside of the disease-spot consisted of conidia, very like those of some Ascomycetes. The author examined the anatomical connexion between the conidia and the resting-spores, and showed that the conidia really belong to the same mycelium —in other words, the conidia are a second kind of spore of the Entyloma .

The life history of Plasmodiophora brassicae Woron

1972 ◽  
Vol 180 (1058) ◽  
pp. 103-112 ◽  
Keyword(s):  
Life History ◽  
Root Hair ◽  
Plasmodiophora Brassicae ◽  
Root Hairs ◽  
Secondary Phase ◽  
Tissue Cultures ◽  
Resting Spore ◽  
Resting Spores ◽  
Seedling Roots ◽  
History Of

Resting spore germination and the root hair stages of the life history of Plasmodiophora brassicae were studied in stained preparations of infected Brassica rapa seedling roots. Naked protoplasts, usually possessing two unequal flagella, were released from resting spores through a small circular pore. They penetrated the root hairs of B. rapa and there developed into plasmodia which, after becoming multinucleate, cleaved to form zoosporangia con­taining incipient zoospores. Biflagellate zoospores were released from root hair zoosporangia and fused in pairs, although karyogamy did not occur. The resulting binucleate zoospores infected the cortical dells of B. rapa to form binucleate plasmodia, the earliest stages of the secondary phase of the life history. These findings are discussed in relation to previous studies on the life history of P. brassicae in Brassica plants and in Brassica tissue cultures, and a new complete life history, including nuclear fusion in the secondary plasmodium, is suggested for the organism.

scholarly journals STUDIES IN THE ENTOMOPHTHORACEAE. I. Observations on the genus Conidiobolus

1969 ◽  
Vol 21 (2) ◽  
pp. 191-200
Author(s):  
Arthur G. Kevorkian
Keyword(s):  
Plant Pathology ◽  
Puerto Rico ◽  
Life History ◽  
New Combination ◽  
College Of Agriculture ◽  
Resting Spores ◽  
History Of ◽  
Biometrical Study ◽  
Infection Experiments

A comparative morphological and biometrical study on artificial media, has been made of strains of Conidiobolus villosus obtained from the Farlow Herbarium, the Centraalbureau door Schimmel-cultures, and isolated directly from termites in Cuba. Furthermore, infection experiments have shown that the fungus which has hitherto been considered a saprophyte may adapt itself to a parasitic habit, especially on termites. The Derx strain from Holland, in contrast to the others, appears to be strictly sapro phytic. Moreover, in the life-history of the species in question an additional stage has been observed which consists of the production of minute conidia borne at the tips of the spiny appendages of the villose conidia or "resting spores". For these reasons a new combination, Entomophthora coronata (Cost.) bas been made and Delacroixia coronata and Conidiobolus villosus have been reduced to synonomy. Department of Botany and Plant Pathology, College of Agriculture, Mayagüez, Puerto Rico.

scholarly journals VIII. On the structure and life-history of entyloma ranunculi (bonorden)

1887 ◽  
Vol 178 ◽  
pp. 173-185 ◽  
Keyword(s):  
Life History ◽  
Careful Observation ◽  
Large Group ◽  
Resting Spores ◽  
History Of ◽  
Established Genus

The attention of mycologists has been long directed to the study of the Ustilagineæ, not only on account of their morphological peculiarities, but even more especially because the economic questions arising from their relations to our crops, &c., have assumed such proportions as to force this group of parasites far into the foreground. Interesting and important as are the parasitic habits of the Ustilagineæ, however, and much as they have been investigated, it has to be admitted that we know as yet very little about them. Two or three of the most common forms, it is true, have been so often studied by different observers that they may be regarded as worked out sufficiently to allow of our regarding them as types; but it needs no very extensive acquaintance with the group to satisfy ourselves that the best known forms are not the simplest, and that much still remains to be accomplished in this large group. It is not only that the Ustilagineæ are so minute, but they are so peculiarly modified, and so specialised as parasites, that the most careful observation is necessary in making out the numerous points in their structure; in addition, observers still differ considerably as to the interpretation of some of the facts of structure which are established. Taking the most recent systems of classification, we may regard the Ustilagineæ as comprising the following genera, Ustilago,Tillertia, Urocystis, Schizonella , and Entyloma , and so far shall be in accordance with all the modern authorities; when we come to such genera as Geminella,Sphacelotheca, Doassansia (Cornu), and Graphiola (Fischer) and some others, the matter becomes more complicated, and special investigations are still needed to determine the limits of the genera and group. Entyloma , however, is a well-established genus, and now includes some fifteen or sixteen species. They are parasitic in the mesophyll of the leaves of various plants, and are characterised by producing rounded resting-spores as intercalary swellings on the very fine, septate, intercellular mycelium; these spores germinate like those of Tilletia . In Tilletia , however, the resting-spores form dense powdery aggregates, which is not the case with the more isolated spores of Entyloma .

Observations on the biology of Afrotropical Hesperiidae (Lepidoptera) principally from Kenya. Part 3. Pyrginae: Celaenorrhinini

Zootaxa ◽  
2011 ◽  
Vol 3033 (1) ◽  
pp. 1 ◽  
Author(s):  
MATTHEW J. W. COCK ◽  
T. COLIN E. CONGDON
Keyword(s):  
Life History ◽  
Life Histories ◽  
White Powder ◽  
Food Plants ◽  
History Of ◽  
Group 2 ◽  
Frontal Projection ◽  
Group 1

Partial life histories for 15 species and two subspecies of Afrotropical Celaenorrhinini (Hesperiidae: Pyrginae) are described and illustrated: Celaenorrhinus plagiatus Berger, C. undescribed nr. dargei Berger, C. proxima proxima (Mabille), C. proxima maesseni Berger, C. zanqua Evans, C. humbloti (Mabille), C. sanjeensis Kielland, C. galenus opalinus Butler, C. galenus biseriata Butler, C. handmani Collins & Congdon, Eretis umbra maculifera Mabille & Boullet, E. lugens (Rogenhofer), Sarangesa phidyle (Walker), S. motozi (Wallengren), S. haplopa Swinhoe, S. maculata (Mabille) and Triskelionia compacta (Evans). The published information on other species of the tribe is summarised, and generalisations are made for the tribe in Africa. All species of Celaenorrhinus, Eretis and Sarangesa spp. reared to date use Acanthaceae as food plants, but T. compacta feeds on a Fabaceae and Ortholexis hollandi Druce feeds on an Apocynaceae. Three groups of Celaenorrhinus spp. are recognised based on their pupae: Group 1 having brown pupae with cephalic projections, Group 2 having green pupae, with no cephalic projections, and a very long proboscis sheath, and a third group based on published illustrations of the life history of C. mokeezi (Wallengren), in which the pupa is generally covered with white powder, and has just a short blunt frontal projection. Loxolexis Karsch is returned to synonomy with Katreus Watson, stat.rev. and Ortholexis Karsh stat rev. is reinstated for the species which had been placed in Loxolexis: O. holocausta (Mabille) comb. nov., O. dimidia (Holland) comb. nov. and O. hollandi Druce comb. rev.

Sequence of events in the germination of the resting spore of Synchytrium endobioticum, European pathotype 2, the causal agent of potato wart disease

1986 ◽  
Vol 64 (9) ◽  
pp. 2144-2150 ◽  
Author(s):  
Michael C. Hampson
Keyword(s):  
Life History ◽  
Causal Agent ◽  
Wart Disease ◽  
Potato Wart ◽  
Synchytrium Endobioticum ◽  
Potato Wart Disease ◽  
Resting Spore ◽  
Sequence Of Events ◽  
Resting Spores ◽  
History Of

Populations of freshly harvested to 4-year-old resting spores of Synchytrium endobioticum (Schilb.) Perc. from sand compost and aqueous immersion cultures were observed, using normal and television microscopy. Germination vesicles were found in aging cultures: at 49 days in sand compost or peaking at the 11th day in aqueous immersion. Freshly harvested spores gave rise to the largest quantity of vesicles in aqueous immersion. The ability to produce vesicles fell off in rapid exponential fashion with time after spore harvest. Release of the sporangia from the enveloping vesicles and discharge of zoospores from sporangia were studied in detail through the use of videotape recordings. This is the first reported description of these phenomena in the life history of S. endobioticum.

Experimental life history of Echinostoma cinetorchis

1990 ◽  
Vol 28 (1) ◽  
pp. 39 ◽  
Author(s):  
S H Lee ◽  
J Y Chai ◽  
S T Hong ◽  
W M Sohn
Keyword(s):  
Life History ◽  
History Of
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