摘要:

Flangas, A. L., and J. G. Dickson. (U. Wisconsin, Madison.)The genetic control of pathogenicity, serotypes and variability in Puccinia sorghi.Amer. Jour. Bot. 48(4): 275–285. Illus. 1961.—Four urediospore clones ofP. sorghiwere inbred through the alternate host,Oxalis, and the recombinant lines were compared with the mother clones for changes in pathogenicity and serological reaction. The aecial, inbred recombinant lines were scored for pathogenicity on 6 inbred lines of maize, 4 of which contained single, dominant alleles isolated from a single gene locus each conditioning differential rust reaction and Pop 35 and Pop 36, each with 2 recessive genes. The inbred, recombinant lines from each of the 4 mother clones reflected similar dimensional changes from original pathogenicity, that is, an ultimate gain or loss in host range or specificity. Based on reaction type incited on the 4 allelic differential hosts, continued inbreeding through 3 generations did not segregate homozygous pathogenic complements into distinct pathogenic biotypes. A similar array of pathogenic types was produced after each generation of inbreeding. The suppressed pathogenicity types in the dicaryotic line were revealed only through recombination. Hybridization between dicaryotic lines of selected pathogenic types of sibling and nonsibling pedigree confirmed the indeterminate nature of the pathogenic locus. The genetic basis of the commonly occurring mesothetic‐X reaction (necrotic flecks and uredia of varying size surrounded by chlorotic and necrotic areas) is explained by the heterologous complementarity of fit of the interacting genic systems (genetic units). The heterologous mesothetic‐X reactions offer ambiguous definition to the specificity state of the interaction and cannot be explained on the discrete gene‐for‐gene basis of rust reaction. Antisera produced from the pathogenic types differentiated the homologous from the heterologous combinations and revealed cross‐reactions withP. graminis avenae.The comparative antigen constitution of the urediospore clones and the sibling recombinants thus far reveal a possible parallel existing between the modes of inheritance of pathogenic specificity and antigenic specificity.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11638.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Rosinski, MartinA. (U. Maine, Orono.)Development of the ascocarp of Ceratocystis ulmi.Amer. Jour. Bot. 48(4): 285–293. Illus. 1961.—A study of the development of the perithecium ofCeratocystis ulmiwas conducted using classic histological techniques. This study revealed the presence of a singular combination of primitive and advanced characteristics. The perithecium possesses a simple centrum made up only of ascogenous hyphae and small, spherical asci, but croziers are formed prior to ascus formation, and the ascogenous hyphae are arranged in a hymenium. Since development ofC. ulmicompares closely with most other accounts of development in other members of the genusCeratocystis, it appears thatCeratocystisis a good taxon. In addition, because of its intermediate nature and becauseCeratocystisis the type genus of the family Ophiostomataceae, this family should be placed in a separate order, the Ophiostomatales.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11639.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Goldstein, Solomon. (Yale U., New Haven, Conn.)Studies of two polycentric chytrids in pure culture.Amer. Jour. Bot. 48(4): 294–298. Illus. 1961.—A study was made of some of the chemical and physical factors affecting the growth ofNowakowskiella elegansSchroeter andN. ramosaButler in pure culture. Maximal harvests of the former were obtained at 15°C. and those of the latter fungus at 20°C. Media buffered at pH 6.4 favored their growth; light had no effect upon yields; and harvests increased markedly in response to shaking. Both fungi required an exogenous supply of thiamin with maximum yields obtained upon incorporating 10μg./l. of the vitamin into a thiamin‐deficient medium. Inorganic nitrogen salts and several organic nitrogen compounds were readily metabolized by these water molds. The use of xylose, glucose, or mannose as the sole source of carbon gave optimal yields of both organisms and neither utilized a variety of sugar acids and alcohols.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11640.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Wilson, JamesF. (Hartnell Coll., Salinas, Calif.), LauraGarnjobst, and EdwardL. Tatum.Heterocaryon incompatibility in Neurospora crassa—micro‐injection studies.Amer. Jour. Bot. 48(4): 299–305. 1961.—Heterocaryosis inNeurospora crassais known to be controlled, at least in part, by the genesCDand their alternate allelescd.If either or both genes differ, a lethal, cytoplasmic incompatibility reaction occurs, effectively preventing the formation of a heterocaryon between strains of the same mating type. This reaction has been further investigated, utilizing a micrurgical approach involving micro‐injection of cytoplasm and extracts. The injection of compatible cytoplasm and extracts was harmless to the recipient cells, but injection of incompatible cytoplasm and extracts was lethal. The extracts were subjected to various chemical and physical treatments and tested, using micro‐injection as an assay method. The results of these tests strongly indicate that a soluble cytoplasmic protein (s) is involved in the heterocaryon‐incompatibility reaction.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11641.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Lam, S. L., and A. C. Leopold. (Purdue U., Lafayette, Indiana.)Reversion and reinduction of flowering in Perilla.Amer. Jour. Bot. 48(4): 306–310. Illus. 1961.—Plants ofPerilla crispa(Thunb.) Tanaka ultimately revert to the vegetative state provided that they have received not more than about 20 cycles of short photoperiods. Reversion is markedly promoted by repeated debudding of plants induced with 35 cycles or less. Reverted plants ofPerillacould be reinduced twice by photoperiodic treatment of the originally induced leaves. Timing experiments to measure the flow of flower stimulus from induced leaves suggest a gradual loss of the stimulus, as indicated by increased time to appearance of flowers and decreased flower number. It is concluded that after the inductive treatment is withdrawn, the effectiveness of the flower stimulus coming from the leaf declines with time. It is suggested that reversion is made possible by the decline of effective flower stimulus coming from the induced leaves.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11642.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Sun, C. N. (Washington U., St. Louis, Mo.)Submicroscopic structure and development of the chloroplasts of Psilotum triquetrum.Amer. Jour. Bot. 48(4): 311–315. Illus. 1961.—Aerial stems and stem tips ofPsilotum triquetrumwere used for the study of the fine structure and development of chloroplasts. The chloroplasts ofPsilotumare ellipsoidal, with a principal axis of approximately 13 μ and a short axis of approximately 3.6 μ. They are bounded by a well‐defined outer membrane which consists of 2 layers. Within the laminar system of the stroma, the lamellated grana appear as sharply defined regions. The grana are about 1–1.6 μ in diameter. They are distributed more or less uniformly throughout the entire chloroplast with the exception of a very narrow peripheral zone. Relatively large, osmiophilic globules occur in groups in the stroma. The development of thePsilotumchloroplast may be summarized as follows: (1) in the undifferentiated proplastid, vesicles occur; (2) lamellated layers are formed by the fusion of vesicles; (3) the lamellae multiply by a process of thickening and splitting; (4) the grana are differentiated within a certain area by heterogeneous deposition of material and by further cleavage of the lamellae. Osmiophilic globules are present throughout the developmental stages, and increase in number and size with increase in age of the chloroplast.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11643.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Boke, NormanH. (U. Oklahoma, Norman.)Structure and development of the shoot in Dolicothele.Amer. Jour. Bot. 48(4): 316–321. Illus. 1961.—A study of 2 species ofDolicothelereveals that although they have dimorphic areoles and a pattern of spine development similar to those of certain mammillarias, they share a significant number of ectomorphic and endomorphic characters with coryphanthas of the “vivipara group.” These include a tendency toward a cespitose habit; relatively large flowers; green fruits; pitted seeds; medullary vascular systems; forking of the main tubercle traces in the bases of the tubercles; lack of mucilage cells; thin‐walled epidermis and hypodermis, both devoid of crystals; and large, druse‐like crystalline aggregates in older parts of the pith and cortex. The evidence suggests thatCoryphantha viviparaand closely allied species are the nearest extant relatives ofDolicothele.It would, therefore, seem inconsistent to returnDolicotheletoMammillariaunless an author's viewpoint were so conservative that he was willing also to return most, if not all, coryphanthas and escobarias to that genus.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11644.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Darlington, H. T., and G. P. Steinbauer. (Michigan State U., East Lansing.)The eighty‐year period for Dr. Beal's seed viability experiment.Amer. Jour. Bot. 48 (4): 321–325. 1961.—Seeds of 20 species of plants were buried 80 years ago on the Michigan State University campus. Bottles have been dug up periodically in the intervening years and the seeds tested for viability. A bottle representing the 80‐year period of burial was dug up this spring and the contents distributed uniformly on the surface of sterilized soil in the greenhouse. Of the 20 species whose seeds were buried in 1879, only 3 have survivors as viable seeds. These are the same 3 that had survived the 70‐year burial period, namely: curled dock,Rumex crispus;evening primrose,Oenothera biennis;and moth mullein,Verbascum blattaria.The low percentage survival of curled dock (2%) indicates that the longevity of the buried seeds of this species is nearing the end. The situation is more favorable for evening primrose, with 10% survival. The third, moth mullein, has about as many survivors as 10 years ago, a remarkably high figure of 70% viability. Since there has been no significant drop in viability of the buried seeds over the last 30 years, it seems highly probable that longevity of buried seeds of this species may extend over a century. A brief summary is given of the current status of the behavior of buried seeds, based on this and other buried seed experiments.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11645.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Garber, E. D., EllenG. Wyttenbach, and T. S. Dhillon. (U. Chicago, Chicago, Ill.)Genetics of phytopathogenic fungi. V. Heterocaryons involving formae of Fusarium oxysporum.Amer. Jour. Bot. 48(4): 325–329. 1961.—Heterocaryons involving mutant strains of 4 formae ofFusarium oxysporumwere studied; the strains differed in nutritional requirements, resistance to acriflavine, and colonial morphology and color. Spores from the heterocaryons gave colonies on minimal medium which resembled one component strain in morphology and color; spores from heterocaryons involving f.pisiyielded colonies on complete medium containing a concentration of acriflavine inhibitory to the other component strain.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11646.x

出版商:Wiley    

年代:1961

数据来源: WILEY

摘要:

Tucker, J. M. (U. California, Davis), W. P. Cottam, and R. Drobnick.Studies in the Quercus undulata complex. II. The contribution of Quercus turbinella.Amer. Jour. Bot. 48(4): 329–339. Illus. 1961.—Quercus undulatahas been interpreted as a hybrid complex involvingQ. gambeliiand several other species, includingQ. turbinella(Tucker, 1961). In the present paper, the total distribution of the hybrids betweenQ. gambeliiandQ. turbinellais given. Lacking direct genetic evidence, proof of hybridity is sought in a demonstration of the morphological intermediacy of these putative hybrids. Population samples of both parental species, other samples containing hybrids, and numerous individual hybrids, are analyzed on the basis of 6 differences between the parental species. The data obtained, presented in the form of pictorialized scatter diagrams, clearly show the general intermediacy of the hybrids. Of the various binomials that have been applied to forms in theQ. undulatacomplex,Quercus paucilobaRydb. applies to this hybrid. The appropriate change in status (Quercus×paucilobaRydb.) is made.

ISSN:0002-9122    

DOI:10.1002/j.1537-2197.1961.tb11647.x

出版商:Wiley    

年代:1961

数据来源: WILEY