摘要:

A study of the mycelium and haustoria of certain rusts ofAbieshas been made. It was found that the mycelium of three rusts have distinguishing characteristics. The haustoria ofMelampsorella Cerastii,Hyalopsora PolypodiiandMilesia polypodophilaare so distinctly characteristic as to serve as diagnostic criteria for the species. The haustoria of sixUredinopsisspecies are similar in type; those of two species ofPucciniastrumare of the same type. The haustoria ofCalyptospora Goeppertianaare hyphal and very slender. The relation of the haustoria of the rusts, up to near maturity, is one of high symbiotic nature inAbies balsamea. The haustoria ofMilesia polypodophilaand certain other rusts in their aecial hosts show a contrast in type to the haustoria in their telial hosts. The haustoria ofMilesia ScolopendriiandM.vogesiacaare hyphal or of loose spiral form. The haustoria ofM.Kriegerianaresemble those ofM.intermedia. The haustoria ofM.Polypodiiare usually characteristically branched, serving as an aid in identification. Haustoria were found to occur in the leaves of 19 species of the Pucciniastreae onAbies. Eighteen of these are described in the aecial host for the first time.

ISSN:1923-4287    

DOI:10.1139/cjr48c-021

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Visible response to injection of flower heads of perennial sow thistle plants with herbicidal concentrations of 2,4-D appeared only in the uppermost regions of the plants. The herbicide moved downward through peduncles supporting treated heads, then it moved upward through neighboring peduncles. Apparently this pronounced ascent of herbicide was associated with transport of plant solutions to regions of rapid development and transpiration.On the other hand, response to injection of severed stems of flowering sow thistle plants was not limited to the region of treatment. The herbicide moved downward in treated stems, upward in their intact lateral branches, leaves, and flowers, and extensively downward and laterally in the root system.Significance of this multidirectional movement is discussed.

ISSN:1923-4287    

DOI:10.1139/cjr48c-022

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The lethal dose of P32and Sr90for wheat, barley, and sunflower seeds is approximately 1.4 microcuries per seed (0.05 rd.). Radioautographs indicate that at five weeks' growth the distribution of phosphorus in a wheat plant is fairly uniform whereas that of strontium is very uneven, practically all the strontium being concentrated in the first two leaves.

ISSN:1923-4287    

DOI:10.1139/cjr48c-023

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

White mustard roots when treated with a slightly alkaline solution of silver nitrate (Tollen's reagent) show, on sectioning the meristem, the accumulation of small black stained particles in the intercellular spaces and intervening cell walls. The production of these particles in the intercellular spaces of treated roots and their complete absence in those of untreated roots indicates the presence of a substance capable of reducing alkaline silver. The presence of this substance strengthens the viewpoint that in the meristem radiating rows of intercellular spaces in white mustard roots provide for the more rapid movement of soluble materials from differentiating vascular strands to the outside. Thus cell position as related to a more accessible food supply is an important adjunct to the general problem of cell development and cell behavior.

ISSN:1923-4287    

DOI:10.1139/cjr48c-024

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The large number of isolates ofChaetomiumspecies obtained from agricultural seeds has made possible the critical study of some sections of the genus. In this paper the species with dichotomously branched hairs are considered. Of the six species previously recognized in this group, four have been isolated from seeds,C.elatumKze. ex Fries,C.dolichotrichumAmes,C.funicolumCooke, andC.indicumCorda. Two new species are described,C.erectumandC.reflexum, making a total of eight recognized species in this group.

ISSN:1923-4287    

DOI:10.1139/cjr48c-025

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

A numerical key for the identification of cultures of 126 species of wood-rotting fungi, with accompanying descriptions of the cultural characters of each species, is presented. The list of species includes many of the fungi most frequently encountered in studies of decay in various hosts, the species having been chosen without restriction as to host or locality. The descriptions and key have been based on cultural characters, both macroscopic and microscopic, that can be demonstrated readily without the aid of elaborate equipment or methods. Thus, cultures were grown in Petri dishes on Difco malt agar and on malt agar to which gallic or tannic acid had been added. They were incubated in the dark at room temperature and examined at weekly intervals for six weeks. Host relationships and physiological and morphological characters proved to be of diagnostic value. The physiological characters used in the key include the pigmentation of the mycelial mat, color changes induced in the agar by the fungus, rate of growth, and effect on media containing gallic or tannic acid. Morphological characters used in diagnosis were types and septation of hyphae, occurrence of secondary spores – chlamydospores, conidia, oidia – and of special structures, such as cystidia and setae, and the formation of fruit bodies. The numerical key will permit the interpolation of additional species as they are described and their code numbers prepared.

ISSN:1923-4287    

DOI:10.1139/cjr48c-026

出版商:NRC Research Press    

年代:1948

数据来源: NRC