摘要:

Studies on damp wheat, bin-burned under conditions simulating natural storage and under adiabatically controlled conditions, produced evidence which provides the basis for the belief that: (1) heating and bin-burning of damp grain during storage are caused primarily by microorganisms; (2) many species of bacteria and of fungi, normally present on grain, are associated with this spoilage; (3) these species are mesophilic, rather than thermophilic; (4) under natural storage, although the grain shows evidence of increased combustion, most of the heat is dissipated. Consequently, the temperature does not rise sufficiently high for thermophiles; and (5) if the temperature in isolated pockets in the mass rises high enough, the thermophiles probably are the result rather than the cause of the high temperature.

ISSN:0008-4026    

DOI:10.1139/b52-001

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The fungusPolyporus versicolorwas shown to produce an extracellular polyphenol oxidase system during growth in submerged culture. The enzyme was stable and active in acid solution, and ozidized lignin, vanillin, ferulic acid, and other phenolic substances. Vanillin and ferulic acid were converted to new compounds as a result of enzyme action, whereas lignin absorbed oxygen and appeared to become more water soluble.

ISSN:0008-4026    

DOI:10.1139/b52-002

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Different plots of Olli barley, Thatcher common wheat, and Stewart durum wheat were each sprayed with a single treatment of 2,4-D. The spraying was done at three-day intervals from emergence to heading time in order to study the effect of the herbicide when applied to plants at various developmental stages. An ester formulation equivalent to 12 oz. acid in 40 gal. of water per acre was used in all cases. Meiosis was studied in spikes obtained from plants of treated and untreated check plots. This material was fixed and stored in Carnoy's Fluid A. Meiotic irregularities were induced by the treatment in some plants of each of the three cereals at all stages of growth. The percentages of abnormal metaphases and anaphases ranged from 0.0 to 35.3 in barley, 0.0 to 33.3 in durum wheat, and 0.0 to 25.0 in common wheat. Chromosomal aberrations were of various types including bridges, fragmentation, asynapsis, aneuploidy, polyploidy, chain and ring formation, and in many cases extreme stickiness of chromosomes. These aberrations are similar to those induced by X irradiation or other mutagens. It is important to determine whether chromosomal aberrations in treated plants are transmissible and also whether gene mutations have been induced. Cytogenetical studies are under way on progenies of treated plants.

ISSN:0008-4026    

DOI:10.1139/b52-003

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Using the technique of vacuum infiltration, either a mixture of glucose plus fructose or a solution of sucrose alone was introduced into detached wheat leaves, and the rates of sucrose synthesis or hydrolysis from these infiltrated sugars were observed. It was found that these rates were not constant during 24 hr., but depended on the time of the day or night when the leaves were cut. Synthesis was high in leaves detached in the forenoon, before sunset, and in the first part of the night. Changes in the rate of hydrolysis were usually mirror images of those of synthesis. It has been concluded that in wheat leaves there exists a diurnal rhythm in their synthetic and hydrolytic potential and that the observed diurnal changes in the rates of sucrose synthesis and hydrolysis represent one of the manifestations of such a rhythm. Sodium fluoride, sodium cyanide, iodoacetate, and dinitrophenol always increased hydrolysis, and usually decreased synthesis. When glucose-1-phosphate, fructose-6-phosphate, and fructose-1, 6-diphosphate were substituted for the corresponding free sugar in a mixture of glucose plus fructose, a decrease in sucrose synthesis was observed. After 24 hr. of starvation the rate of sucrose synthesis declined, and eventually dropped practically to zero at the end of five days. In the same time there was a progressive increase in the rate of hydrolysis.

ISSN:0008-4026    

DOI:10.1139/b52-004

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Meiosis was studied in the haploid ofTriticum vulgareand in its second and third generation selfed progenies derived from pollination of the haploid with normal pollen. In the haploid, 57.6% of the metaphase cells showed one to three bivalents. This is assumed to be evidence of a degree of homology between chromosomes of the haploid set. Random distribution of univalents to the poles was apparently restricted by bivalent and secondary associations. Cells with 42 chromosomes were observed in a few instances. In one case the complement was made up of 21 bivalents. A high frequency of trivalents and quadrivalents was observed in the second and third generations. Presumably crossing over between partially homologous chromosomes, occurring in the haploid, resulted in reciprocal translocations which were transmitted to succeeding generations. Plants with chromosomal deficiency or duplication, observed in the second and third generations, probably originated from union of unbalanced gametes in first generation plants heterozygous for translocations or deficient or duplicated for one or more chromosomes.

ISSN:0008-4026    

DOI:10.1139/b52-005

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The respiratory rate, soluble nitrogen content, protein nitrogen content, water content, reducing sugar content, and sucrose content of each of the four quarters of the first leaf of Khapli Emmer wheat have been determined for plants grown with different soil water supplies. Under dry conditions the first leaf of wheat contains a higher concentration of nitrogenous substances than it does under moist conditions. The water content of the first leaf of wheat grown in dry soil or very wet soil is lower than it is for leaves grown in moderately moist soil. The significance of these two observations is discussed. Further support has been obtained for the view that the concentration of none of the substances determined is solely responsible for the respiratory rates and gradients observed in the leaves. The role of leaf anatomy in controlling and producing the observed respiratory gradients is discussed.

ISSN:0008-4026    

DOI:10.1139/b52-006

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Fucus vesiculosus,F.evanescens, andAscophyllum nodosumhave been analyzed monthly for their content of moisture, mineral salts, organic nitrogen, mannitol, laminarin, and alginate over a period of two years. Plants were collected from two localities, St. Andrews, N.B., and Halifax, N.S. In general, when the ash content was at a minimum in the winter months, alginate was at a maximum. The converse was true in spring and summer. Organic nitrogen and laminarin remained relatively constant throughout the year. Mannitol was highest in the summer and autumn, fluctuating with the temperature of the water. No essential difference was detected between the results of St. Andrews and at Halifax, or between the three species examined. Analyses carried out on samples collected at different times on the same day showed no significant differences.

ISSN:0008-4026    

DOI:10.1139/b52-007

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

The Nova Scotia Research Foundation is making an extensive survey of seaweeds of the Province that are of potential commercial importance. The area in which the survey has been completed extends from Cape Sable Island, Shelburne County to Chebogue, Yarmouth County, and includes also a small part of Digby County. The survey includes both quantitative measurements and biological studies of fucoids,Laminariaspp., andChondrus, in all of which the region abounds. Of 325 miles of coastline surveyed for rockweed, 140 miles are harvestable, bearing approximately 200,000 tons. Results obtained at 255 stations, examined in detail, showed the average density to be 37 lb. per sq. yd. The width of the zone is from 2 to 300 yd., the average being 50 yd.Ascophyllum nodosumforms the greatest percentage of rockweed,Fucus vesiculosusranking next.Fucus serratusis recorded for the first time in this part of the Province.Laminariabeds totalling 12,000 ac. in extent and bearing 900,000 tons were charted. Mortality amongLaminariasporophytes is high and the number in a bed varies from year to year. In 1950 7,997,739 lb. ofChondruswere harvested. Density varies from 1 to lb. per sq. ft.Chondrusbeds are listed and their ecology discussed. Recolonization of denuded areas is described and succession of algal cover noted on denuded areas and on concrete blocks placed inChondrusandLaminariabeds. The survey region is compared with regions surveyed in Scotland. A map of the survey region is included.

ISSN:0008-4026    

DOI:10.1139/b52-008

出版商:NRC Research Press    

年代:1952

数据来源: NRC

摘要:

Natural grassland is associated with poplar and willow groves to form parkland areas on dark soils in the generally forested Peace River region of western Canada. The grassland is described as anAgropyron–Stipa–Carexcommunity. Comprising this community are three subtypes or faciations, viz.Agropyron–Carexon low areas,Stipaon dry slopes, andAgropyron–Stipaon mesic sites. For the entire community 154 vascular species are recorded and for theAgropyron–Stipafaciation, which is the most common native grassland of the region, 139 vascular species, consisting of 36 graminoids, 84 forbs, and 19 woody species. The leading grasses areAgropyron trachycaulum,Stipa sparteavar.curtiseta, andKoeleria cristata. TheAgropyron–Stipafaciation is the "climax" grassland of the region and therefore may be classified as an "association". The occurrence of native grassland areas in the boreal forest region is explained in terms of special physiographic and edaphic features of these areas, notably poorly drained and inadequately aerated soils. Therefore, theAgropyron–Stipagrassland may be interpreted as an edaphic climax. Compared with the fescue grassland of south-central Alberta, the Peace River grassland lacksFestuca scabrellabut has many of the other plants of the fescue association, certain of these assuming the role of leading species. Reliable indicators of early stages in grassland retrogression brought about by heavy grazing are the small sedges,Carex obtusataandC.heliophila.

ISSN:0008-4026    

DOI:10.1139/b52-009

出版商:NRC Research Press    

年代:1952

数据来源: NRC