摘要:

SUMMARYThe teliospores ofMelampsorella cerastiiare developed in the lower epidermis of the young leaves ofCerastium arvensein the spring from a systemic perennial mycelium. Hyphae mass up above the cells of the lower epidermis and from certain hyphal cells of the fungus enlarged binucleate primordial cells are formed. Each primordial cell penetrates the host cell wall and the contents flow in to form a teliospore initial which, by growth and differentiation, develops directly into a single-celled thin-walled teliospore.Following nuclear fusion the teliospore immediately germinates, producing a slender recurved promycelium into which the fusion nucleus migrates. Meiosis occurs here and four uninucleate basidiospores are produced.Teliospores completely fill all of the cells of the lower epidermis of the lower leaves, giving the leaf an orange color. Some teliospores are formed in the middle leaves but are lacking in the upper leaves. Teliospore formation is continuous during the first few weeks and new initials are formed in the cells as the teliospores germinate.Comparisons were made with the other rust species with intraepidermal teliospores which have been examined cytologically.Melampsorella cerastiiis similar in its general development but differs principally in that the teliospore is unicellular.

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024073

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024074

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024075

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024076

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024077

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024078

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

摘要:

SUMMARYOf the seven described species ofStomiopeltis(Hemisphaeriaceae)heteromerisSyd.,S. chilensisSyd., andS. philippinensisSyd., because of their radiate structure, are transferred to the Mi-crothyriaceae.The four remaining species,S. rubi(Fckl.) Petr.,S. cassiaeMendoza,S. citriBitancourt, and the type of the genus,S. aspersa(Berk.) Theiss., form a distinct group in the Hemisphaeriaceae characterized by the non-radiate, irregularly pseudoparenchymic structure of the shield of the superficial, dimidiate-scutate ascocarp, the hyalodidymous ascospores, the presence of pseudoparaphyses and ostioles, and the dark-colored superficial mycelium.S. citrivar.minorBitancourt is elevated to the rank of species and becomesS. minor(Bitan.) Luttrell.Stomiopeltella suttoniaeMendoza, because it is pseudoparaphysate, is transferred toStomiopeltisand becomesStomiopeltis suttoniae(Mendoza) Luttrell.A fungus found onArundinaria tecta(Walt.) Muhl. in Georgia which differs from all previously described species ofStomiopeltisin that its ascocarps are polyloculate is added to the genus as a new species,S. polyloculatisLuttrell. The presence of more than one locule in the ascocarp is not considered sufficient basis for the formation of a separate genus.InS. polyloculatisthe thick-walled, bitunicate asci develop within locules created in the dimidiate-scutate ascocarps by the growth of pseudoparaphyses.Presence or absence of pseudoparaphyses might be employed as the primary criterion in the separation of families in the Hemisphaeriales; but in the absence of sufficient data on development of the ascocarps in the Pyrenomycetes, the present classification of the order upon the basis of shield structure should be maintained.

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024079

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

摘要:

SUMMARY1.Structural studies of active and inactive strains ofS. griseuswere made with light and electron microscopes.2.The vegetative mycelium when young is coenocytic and well branched typically in a monopodial form. Transverse septa are formed in practically all cases in the delimitation of the reproductive cells. Also septa occasionally were observed in the older mycelium.3.The basal portions of new mycelial branches were often seen to be constricted.4.The reproduction ofS. griseusoccurs by means of unicellular, asexual spores (conidia) which are exogenously borne in chains on the aerial mycelium.5.The spores ofS. griseuswere found to be of various shapes: barrel, oval, bean, spherical, and cylindrical. Differences in shape and size were found often, even among the spores of the same chain.6.The progressive stages in the development of sporogenous hyphae can be observed easily in a one to three day old culture on a good sporulation media.7.The aerial sporogenous hyphae showed some differences in morphology among strains growing upon the same medium. Differences were found among active strains, as well as among inactive strains.8.Mature aerial spores often show small fragments of transparent film adhering to the outside wall.9.The spores ofS. griseususually germinate at one or both ends, usually from the points at which they were attached to the adjacent spores or to the hypha. Rarely do they germinate by more than two germ tubes.10.Hyphal fusions and germ tube fusions were observed.11.The nucleus ofS. griseusmay readily be demonstrated in the germ tubes, young mycelium, and in the developing spores. The nuclei are well distributed throughout the cytoplasm of the mycelium. The spores may be uninucleate or multinucleate.12.Spore formation of other species ofStreptomyceswas very similar to that ofS. griseus.13.The reproductive processes of most species ofStreptomycesare far more highly developed than those of any of the bacteria.The writer gratefully acknowledges the assistance of Dr. Seth Pope for helpful criticism of the manuscript and of Mr. G. B. Levy and Mr. Denman Shaw for the technical photographic help and the operation of the electron microscope.

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024080

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

摘要:

SUMMARY1.The saprophytic fungusStreptomyces griseushas been isolated from soils, river muds, insects, plant roots, air, foodstuff, animal excreta, water, decomposing plant material, and dust.2.The majority of the strains found were unable to produce streptomycin, but a few did.3.Active strains varied greatly in their ability to produce streptomycin.4.WhenS. griseusstrains were streaked at the same time, perpendicular to various bacterial testers, they were partially inhibited by some of the bacteria, particularly byStaphylococcus aureus, Bacillus subtilis, and E. coli.5.Studies were made of the behavior of several active and inactive strains ofS. griseus.Variations in growth, sporulation, color, soluble pigment production, odor, and other physiological characteristics were found common to active and inactive strains as well.6.The best sporulating agar medium for one strain may be unsatisfactory for another strain.7.Colony variation is found among colonies derived from the same isolate. The active strains may be improved by selection and testing individual colonies.8.Better stability of cultures was obtained by smearing the whole surface of the nutrient agar medium with a heavy suspension of spores rather than by streaking or seeding at one point.9.Lyophilized cultures of active strains ofS. griseuswere found not to differ from the parent cultures in morphological, physiological, or biochemical characteristics.The writer wishes to acknowledge the photographic work which was done by Mrs. Marie Lommel and Mr. G. B. Levy.

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024081

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1946.12024072

出版商:Taylor&Francis    

年代:1946

数据来源: Taylor