摘要:

Wheat plants grown in culture solutions limited in one or two nutrients were analysed for nitrogen, phosphorus, sulphur, potassium, calcium, and magnesium.Limiting nitrogen reduced the size of plants and the weight of all of the nutrients absorbed except phosphorus. Percentages of phosphorus and sulphur increased.Limiting calcium had the least effect on uptake of nutrients.Limiting potassium had no effect on percentage of anions but decreased the total weight absorbed. The percentages of calcium and magnesium were increased, while weight of calcium was increased in one series.Although limiting nitrogen and calcium had marked effects on the ratios of various ions absorbed, the total anion: cation ratio was not affected. Limiting potassium, however, caused an increase in anion: cation ratio.

ISSN:1923-4287    

DOI:10.1139/cjr44c-007

出版商:NRC Research Press    

年代:1944

数据来源: NRC

摘要:

When root tips ofTrillium erectumL. are exposed to low temperatures the chromosomes contain regions of reduced diameter and staining capacity. The positions of these regions are constant within the species.The number of "differentiated regions" per nucleus changes with the duration of cold treatment, and at 3 °C. reaches a maximum after 96 hr.The visible differentiation produced by cold disappears within a few hours when the material is returned to higher temperatures.Low temperatures cause non-differential parts of chromosomes to be more contracted than in untreated material, while differentiated regions are unaffected or less contracted than in the controls. The amount of "differentiation" observed is apparently determined by the differential contraction of these parts.

ISSN:1923-4287    

DOI:10.1139/cjr44c-008

出版商:NRC Research Press    

年代:1944

数据来源: NRC

摘要:

The determinations of the smut spore loads present on cereal seed samples revealed that, owing to variability in surface tension and viscosity of the washings, and apparently to some electrical effect, the spore counts were unreliable. These sources of error were very largely eliminated by adding to the washing water a proprietary wetting agent that not only is a good electrolyte but also effectively reduces the surface tension, and by adding to the residue a gelatine sol, which, by virtue of its colloidal properties, promotes a better distribution of the spores.

ISSN:1923-4287    

DOI:10.1139/cjr44c-009

出版商:NRC Research Press    

年代:1944

数据来源: NRC

摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr44c-010

出版商:NRC Research Press    

年代:1944

数据来源: NRC

摘要:

A brief review of the application of the electrical conductivity method of estimating carbon dioxide in respiration measurements is given and an apparatus which employs this method is described. The apparatus was designed and constructed by the authors for the purpose of recording respiratory carbon dioxide output of plant material; it comprises an oscillator, amplifier, and vacuum tube voltmeter that work in conjunction with a special type of absorption tube. Sodium hydroxide solution is used as the absorbing reagent. A simple set-up for automatic recording is described.

ISSN:1923-4287    

DOI:10.1139/cjr44c-011

出版商:NRC Research Press    

年代:1944

数据来源: NRC