摘要:

Fertility was induced by means of colchicine treatments in sterile intergeneric hybrids of the following wheat varieties crossed withAgropyron glaucum:T.vulgarevar. Mosida, Ruby, Milturum, and KharkovT.durumvar. Mindum and Black PersianT.turgidumT.dicoccumvar. VernalT.pyramidaleThree methods of applying colchicine were compared and the "capsule" method was found to be the most economical and effective.

ISSN:1923-4287    

DOI:10.1139/cjr42c-013

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

The molecular characteristics of gluten in sodium salicylate solutions were studied by means of sedimentation velocity, sedimentation equilibrium, and diffusion measurements. The proportion of total gluten protein molecularly dispersed increased with increase in concentration of sodium salicylate up to 12%, but the dispersed portions had essentially the same sedimentation constant (2.5 ± 0.15) regardless of the concentration of the dispersing medium.The most soluble 25 per cent of the gluten was all molecularly dispersed, but was definitely inhomogeneous. The weight-average molecular weight of this fraction was 44,000, but there is reason to believe the minimum weight may be about 35,000. None of the other fractions was entirely molecularly dispersed, the proportion decreasing with decreasing solubility of the fractions. Aggregates of many sizes existed in all of these fractions, but only the most insoluble contained aggregates large enough to cause opacity. Sedimentation constants of the molecularly dispersed portions increased slightly with decreasing solubility, while diffusion constants decreased markedly. None of the fractions yielded normal curves (diffusion diagrams) but the more soluble the fraction, the more nearly normal the curve. The inhomogeneity responsible for the varying rates of diffusion was due partly to differences in proportion and properties of the molecularly dispersed gluten and partly to aggregates.All properties showed progressive changes both within and between the arbitrarily produced fractions. These results, therefore, support the hypothesis that gluten is a protein system showing progressive and regular changes in properties with change in solubility.

ISSN:1923-4287    

DOI:10.1139/cjr42c-014

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

The course of respiration during the early stages of germination is recorded for a number of varieties of bread anddurumwheats. Germination is marked by three consecutive respiratory stages which are characterized by the rate at which the acceleration in carbon dioxide output occurs. These stages are (a) a slow rate of acceleration, (b) an increased rate followed by a decreasing rate, and (c) a final uniform and relatively high rate. Water absorption rate under the experimental conditions used does not appear to affect these respiratory stages. The infection of germinating grains by fungi reduces their respiration. Possible physiological explanations of the respiration stages are discussed.

ISSN:1923-4287    

DOI:10.1139/cjr42c-015

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

A thermostable diffusible substance produced by an aerobic spore-forming bacillus in a potato dextrose peptone medium containing 2% dextrose, 1% peptone, and adjusted to pH 6.5 was found to inhibit the growth of 77 out of 81 species of parasitic and saprophytic fungi. Actinomycetes were more tolerant than fungi, though some were completely inhibited. The majority of streptococci, staphylococci, bacilli, lactobacilli, and clostridia tested were suppressed by the toxic medium. Gram negative organisms were unaffected.Bacillus subtilisand, to some extent,B.cereusandB.pumilusproduced thermostable substances toxic toRhizoctonia Solani. Soil, bentonite, and activated charcoal completely adsorbed the toxic agent, agar was less effective and talc not at all. The toxic substance passed through cellophane, parchment, and collodion, resisted autoclavingfor30 to 45 min. at 15 lb., but was destroyed rapidly by heating in alkaline, but less rapidly in acid solutions; it was not inactivated by aeration and retained its potency for many months at 0 °C.; ether, chloroform, benzene, ethyl acetate, andNbutyl alcohol could not remove it from the toxic medium but it could be eluted partially from charcoal with 95% ethyl alcohol. The substance has not as yet been identified.

ISSN:1923-4287    

DOI:10.1139/cjr42c-016

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

An adaptation of the Rossi and Cholodny glass slide technique was found to be an effective means of measuring the growth ofRhizoctonia Solaniin soil. After a 6 day and a 12 day period, the extent of growth of 11 isolates of this fungus was, for each growth period, less in a vertical than in a radial direction. Certain isolates grew faster than others. A comparison of the radial growth of a faster and of a slower growing isolate at soil depth of 2, 4, and 6 in. showed that the extent of growth decreased with depth, being significantly greater for both isolates at the 2 in. than at the 6 in. level.In pathogenicity tests on wheat with 10 of these isolates, the disease rating for each isolate was greater in natural than in steam sterilized soil, and in soil with a proportion of inoculum to soil of one to six than of one to three. The addition of cellulosic organic material, grass- or straw-meal, to unsterilized soil was effective in reducing the parasitic action of all isolates. Two distinct types of injury were observed: the one, a severe form of root injury, resulting in reduced plant growth; the other, a girdling of the coleoptile or lower stem tissue, usually unaccompanied by adverse effects on plant growth. The first type was produced by two slow growing isolates of English origin, the second by faster growing isolates of Canadian origin. On the basis of these differences, it is suggested that the root injuring isolates be regarded as a variety ofR.SolaniKühn.

ISSN:1923-4287    

DOI:10.1139/cjr42c-017

出版商:NRC Research Press    

年代:1942

数据来源: NRC

摘要:

Using the transfer and maceration methods, an analysis of the fructifications ofDactylotheca parallelaKidston has been made to obtain a more adequate description of their structural features for the purpose of revising its systematic position.The results of the analyses show that the fructifications, hitherto believed to be single sporangia inserted superficially on the lateral veinlets of the lower surface of the pinnules, are really stalked, three- to five-component synangia inserted in the marginal regions.The spores extracted were generally smooth and thin-walled, measuring 19 μ in average diameter, and the number per synangium was calculated to be 10,000.On the evidence produced, the plant cannot belong to the genusDactylotheca, and after a comparison with the forms that it most closely resembles it has been concluded that it should belong to the genusAsterothecawhich has been extended here to include the scolecopteroid types.Its fructifications appear to be more marginal than those of all otherAsterothecaspecies, their orientation is comparable only with that inA.hemitelioides, and they resemble the scolecopteroid fructifications in that they are stalked.It has accordingly been regarded as specifically distinct, and namedAsterotheca parallelan. comb.Its affinities have been discussed, and the evidence seems to warrant its classification as a marattiaceous fern.

ISSN:1923-4287    

DOI:10.1139/cjr42c-018

出版商:NRC Research Press    

年代:1942

数据来源: NRC