ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017174

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017175

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

摘要:

SUMMARYDipodascus uninucleatuswas obtained in culture from a dead pupa ofDrosophila melanogaster.The vegetative growth is yeastlike and no asexual reproduction occurs. The fungus is homothallic. The cells are consistently uninucleate. The asci arise from the fusion of two undifferentiated uninucleate cells and develop after nuclear fusion. The mature asci are elongate, multispored and bear a marked resemblance to those described forDipodascus albidusLag.D.uninucleatuspossesses characters which suggest a closer relationship of the genus Dipodascus with the Endomycetaceae than has hitherto been recognized.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017176

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017177

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017178

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

摘要:

SUMMARYThree species of discomycetes of the family Dermateaceae have been distinguished onNemopanthusand their conidial relations established by cultures.1.Dermatea Peckiana(Peck) Groves of which the imperfect stage isMicropera stellata(Ellis) Jaczewski.2.Godroniopsis NemopanthisGroves of which the imperfect stage isSphaeronema PeckiiSaccardo and Sydow.3.Durandiella Nemopanthis(Peck) Groves of which no imperfect stage has been found.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017179

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017180

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

摘要:

SUMMARY1.The conidia and germ tubes ofHelminthosporium sativumare multinucleate, whereas hyphal cells are uninucleate to multinucleate, and young conidiophores are usually uninucleate. All nuclei in the conidia produced on the same conidiophore are perhaps derivatives of a single nucleus and hence genetically alike.2.True hyphal fusion between races ofH. sativumis common but rare betweenH. sativumand other dark-spored species. However, pseudo-hyphal fusion between species ofHelminthosporiumis not uncommon.3.Cultural comparisons were made of 207 hyphal-tip isolates obtained from 103 germinating conidia taken from colonies giving rise to variants or from mixed colonies on agar drops. All the isolates from a single conidium were identical with the original culture.4.Cultural comparisons were made of 524 conidial isolates obtained from 205 individual conidiophores taken from mixtures of 2 distinct races or species growing on agar drops or from colonies derived from barley tissues infected with 2 or more distinct races or species ofHelminthosporium.All the isolates from the same conidiophore, with two exceptions, were identical culturally.5.Variants occur frequently inHelminthosporiumspp. either in the form of sectors or“patches.”AlthoughH. sativumrace 1 has been cultured for 17 years, it still gives rise, under certain conditions, to numerous variants of different types.6.Potato-dextrose agar rendered stale by certain bacteria was found conducive to the development of variants.7.The results indicate that genetic variation inH. sativumis caused primarily by nuclear change rather than by heterocaryosis.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017181

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

摘要:

SUMMARYProtodontiaandTremellodendronhave the same cytological history as the other genera of the Tremellaceae studied by the writer. The following differences are noted, however. InProtodontiathe epibasidia are definitely affected by the amount of“jelly”surrounding the hypobasidium and vary from very inconspicuous objects found in the flat surface of the fruit-body to long well- developed bodies found in the teeth. In this genus basidia-like sterile bodies occur, each containing only one nucleus and a very scant cytoplasm. InTremellodendron,the fruit-body is composed of three layers: a central mass of densely packed hyphae growing longitudinally in the fruit-body; surrounding this, a layer of radially growing much-branched hyphae; and at the surface a layer of slender tangled hyphae in which are formed the basidia. The basidia do not occur as a continuous layer, but individually. The large fusion nucleus of a mature basidium has the chromatin peripherally located. No abortive structures were observed inTremellodendron.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017182

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor

摘要:

SUMMARYIntensive studies of 208 single-ascospore mycelia ofHypomyces Ipomoeaehave shown each to be self-sterile and to fall into one or the other of two reaction groups. Members of each reaction- group are sterile when matedinter se,and react with only one of the two tester-strains bearing opposite sexual-reaction factors. All matings of members of one group with members of the other group have proved fertile.All single-spore mycelia produce sterile bodies which are with reason assumed to bear the female sex organs. Nearly all such bodies in compatible matings develop into fertile perithecia.Microconidia of members of either reaction-group appear to be capable of“spermatizing”the female sex organs of members of the other reaction-group.It is proposed that each single-ascospore mycelium is hermaphroditic, but self-sterile. Each monoploid nucleus must, then, possess the potentialities of both sexes. Hence, sexual-reaction factors, rather than sex factors or sex chromosomes as such, are segregated at meiosis. The data strongly suggest that a single allelomorphic pair is concerned.

ISSN:0027-5514    

DOI:10.1080/00275514.1937.12017183

出版商:Taylor&Francis    

年代:1937

数据来源: Taylor