摘要:

SUMMARYThe early stages in the development of the oögonium and the antheridium ofSclerospora graminicolawere found to be similar to those described for other members of the Peronosporales. A distortion, which was not attributed to poor fixation, was characteristic of nuclei entering the young oögonium. There were at least two divisions of most, if not all, of the nuclei in the oögonium and antheridium. The fusion of the two sexual nuclei took place very slowly, so that they had not yet fused when the oöspore had reached the resting stage. The haploid number of chromosomes was found to be present at metaphase of all mitoses in the developing sex organs.After the nuclei in the oögonium ceased to divide, all except one were found in the periplasm. The one functional female pronucleus remained within the dark mass of cytoplasm in the center of the oôplasm. The conjugation tube penetrated into the oöplasm and one nucleus left the antheridium, passed through the conjugation tube and into the oöplasm. After the entrance of the male pronucleus, the wall of the oöspore was formed from the oöplasm and at the same time a large central body was formed. In the mature oöspore the wall of the oögonium became wrinkled and came into contact with the wall of the oöspore. The two walls were not observed to have become continuous at any point.A few hours after the oöspores had been placed in the conditions under which they germinated the fusion nucleus divided. Subsequent divisions followed until the oöspore contained typically about 32 nuclei. At late prophase of the division of the fusion nucleus the chromosomes were seen to be associated in pairs. At anaphase the haploid number of chromosomes was found to go to each pole. Late prophase stages of dividing nuclei found during the later development of the germinating oöspore were observed to contain the haploid number of chromosomes. The haploid number of chromosomes was found to be 14. However, the small size of the chromosomes made it difficult to be absolutely certain of the exact number. Meiosis, therefore, occurs during the first two divisions of the fusion nucleus.During the divisions of the nuclei just described the central body was in most cases completely digested and the wall of the oögonium became thin. The germ tube arose at a point near the thin spot in the oögonial wall, at which spot the antheridium was attached to the oögonium. The tube penetrated through the wall of the oögonium at this spot. The cytoplasm and nuclei were observed to enter the germ tube. At the time of leaving the oöspore and entering into the germ tube, the nuclei were elongated and somewhat pointed.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017186

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017187

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

摘要:

SUMMARY1.Phlyctochytrium chaetiferumhas been found on dead cells and filaments ofHydrodictyon reliculatumandOedogoniumsp. which had been growing in battery jars in the laboratory. It is characterized by oval and somewhat pyriform extramatrical zoösporangia on which occur from 3 to 30 elongated, hyaline, continuous, branched, comparatively stiff but flexible hairs which may occasionally attain a length of 200μThe intramatrical portion of the thallus consist of a globular, spindle-shaped, elongated, or irregular apophysis and a fairly extensive rhizoidal system oriented on its base or sides.2.The zoöspores are hyaline, spherical, 2.5 to 4μin diameter, with a large clear refractive globule in the center and a single posteriorly attached cilium which is approximately four times the diameter of the spore in length.3.The resting spores are extramatrical, hyaline, oval to spherical in shape, with smooth thick walls and one or more large refringent globules in the center. So far no gametic fusion has been observed in relation to their development, nor have any germination stages been found.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017188

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

摘要:

SUMMARY1.A new fungus regarded provisionally asArachniotus aureus(Eidam) Schröter, was found on pellets apparently regurgitated by buzzards.2.Upon comparison with Nannizzi's species by the same name, there was found to be no concurrence between the characters of the two fungi.3.A preliminary study of the development showed:(a)a true sexual process to occur, and(b)crosier formation accompanied by conjugate nuclear division in the formation of asci.The stages are compared with figures drawn but not interpreted by Dale (1903).4.Study of single ascospore cultures along with the cytological findings now available show that this species is probably monoecious and self-fertile.5.The significance and importance of the occurrence of croziers and monoeciousness in this and related organisms is emphasized.6.The naming of this apparently new fungus is being left until a more comprehensive study of the family is presented.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017189

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017190

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

摘要:

SUMMARYA decay of citrus fruits caused by a new species ofCandelosporawas found on an orange fruit at Citra, Florida, in 1932. Inoculations showed the fungus capable of decaying lemons, oranges, and grapefruit, mature fruit being more susceptible than immature fruit.The fungus grown on glucose-potato agar has an optimum temperature for growth near 25.0°C., a minimum between 7.7°and 11.8°C., and a maximum between 30.4°and 35.0°C.This fungus differs fromCandelospora ilicicolaHawley, apparently the only other species of the genus described, in having smaller spores, in having fawn to vinaceous-colored mycelium instead of white tufts, in the lack of mucus in the heads, and in having peculiar aerial hyphae which terminate in swollen cells. Conidiophores grow out laterally from these beacon-like hyphae.The fungus is described as a new species under the nameCandelospora Citri.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017191

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017192

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017193

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017194

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017195

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor