摘要:

AbstractResults are presented showing differences in the relative toxicity of sodium MCPA (the sodium salt of 2‐methyl‐4‐chlorophenoxyacetic acid) and sodium 2.4‐D (the sodium salt of 2: 4‐dichlorophenoxyacetic acid) toBrassica albasprayed in the field. The apparent toxicity ratio is shown to vary with: (a) the interval after spraying at which observations are made; (b) the dosage applied; (c) the incidence of rain after spraying; (d) the particular salt used.Spray droplets of sodium 2,4‐D dry out relatively completely, leaving a crystalline deposit, whereas those of sodium MCPA tend to dry to a non‐crystalline film. It is suggested that the observed variation in relative toxicity may be due to differences between the two materials in the facility with which they enter the leaf; sodium MCPA penetrates the more readily owing to the non‐crystalline nature of the spray deposit, and thus gives better results when rain follows after an interval which much decreases the efficacy

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031201

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe amount of potassium fixed by four soils as a result of alternate wetting and drying at an elevated temperature (95°) increased with the clay content of the soil. Electrodialysis released about half of the fixed potassium from two of the soils, about two‐thirds from another soil and all the fixed potassium from the fourth. The amount of potassium fixed by an individual soil increased with increasing potassium treatments, but the percentage of the fixed potassium removed by electrodialysis was independent of the amount fixed. It would appear that when potassium is fixed by soils, more than one type of compound or class of compounds of potassium may be form

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031202

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

Abstract1. Cultivation experiments were conducted for two years on four soils in the Midlothians, differing markedly in fertility and other physical and chemical conditions.Cultivation treatments consisted of ploughing to a depth of 8 in. and shallow and deep cultivation with a tined cultivator to depths of 2 and 4 in. respectively.2. The crop removed greater amounts of nitrogen and produced greater growth and greater yields in the ploughed plots than in the tine‐cultivated soil in the unfertilized plots of two of the soils. When the plots were manured the differences between the cultivation treatments disappeared in the richer soils but persisted between ploughing and one or both types of tine cultivation in poor soils, according to the fertility status of the soil.3. The type of cultivation affected the vegetative growth of the crop more than the grain production in the unfertilized plots of the richer soil: straw/grain ratios differed significantly, varying from 1.53 for deep ploughing to 1.42 and 1.35 for deep and shallow tine‐cultivation respectively; the grain yields, however, showed no significant difference due to cultivation treatment.No such cultivation effects on straw/grain ratios were apparent in the poor soil.4. The response of the crop to nitrogenous fertilizer varied with the type of cultivation; in the tine‐cultivated plots, it was twice as great as in the ploughed plots, indicating a greater nitrogen deficiency in the cultivated plots. Factors contributing to this are discussed.5. The level of fertility of a soil seemed to be the determining factor in its response to different types of cultivation. In a well drained and fertile soil, tine‐cultivation to a depth of 4 in., but not to a depth of 2 in., could replace ploughing if an application of nitrogen fertilizer was made to counteract the deficiency in n

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031203

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractTitration curves have been obtained for gelatins prepared by methods designed to show the greatest possible variation. The difference between the curves is fully explained by the loss of amide nitrogen and the consequent increase in free carboxyl groups in passing from one gelatin to the other. Attention has been drawn to an anomaly in the middle portion of the titration curve of native collagen, which can be explained if the substance commonly recognized as collagen is in reality a mixture or a compound of two similar proteins.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031204

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe relative efficiencies of three methods for the determination of peroxide oxygen in fatty materials have been compared using methyl oleate, linoleate and linolenate oxidized under standard conditions to known oxygen‐absorptions. The iodometric method indicated the conversion of 71–91% of the oxygen absorbed to peroxy‐compounds, but the ferric thiocyanate and 2: 6‐dichlorophenolindophenol methods both gave abnormally high results in the presence of atmospheric oxygen, and values which were obviously too low in its absence.Nevertheless, the aerobic ferric thiocyanate method shows excellent reproducibility, requires much less material than the iodometric method, and under any one set of conditions gives results which appear to be directly proportional to the iodometric values.The 2: 6‐dichlorophenolindophenol method behaved similarly in most respects to the ferric thiocyanate method, but reproducibility appeared to be poorer and interference by atmospheric oxygen and by traces of copper when present was mo

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031205

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe method proposed by the authors (see Part II of this series) for the determination of ‘acid‐insoluble lignin’ excludes the humin material which dissolves in 72% (w/w) sulphuric acid but is reprecipitated by dilution. Further work has shown this humin material to possess the properties of lignin. Although it is to be expected that the ‘acid‐insoluble’ lignin will be resistant to the digestive processes and its determination should therefore serve a useful purpose, for the measurement of ‘total’ lignin the method is inadequate. An investigation of the acid‐solubility of lignin has led to the re‐examination of the various separation procedures to obtain a satisfactory method for deter

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031206

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractA rapid differential‐staining method for distinguishing damaged from whole starch granules is described. The method has been applied to plant starches of different origins and to starches damaged by mechanical and chemical means. A relationship is shown to exist between the number of damaged granules, as shown by selective staining, and the susceptibility of the starch to enzymic hydrolysi

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031207

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe relative rates of release during electrodialysis of potassium, calcium and magnesium from field soils, from single‐base soils containing the three cations separately, and from a soil saturated with, equivalent amounts of all three cations, were studied. In all cases potassium was released much more rapidly than either calcium or magnesium. Potassium fertilization of the soil resulted in a quicker release not only of potassium but also of calcium and magnesium. The rates of release of calcium and magnesium were similar from single‐base soils, but the presence of potassium and calcium depressed the rate of release of magnesium. There was little difference in the relative rates of removal of the three bases during leaching of the triple‐base soil with ammonium acetate. The relatively easy release of potassium is possibly connected with the ‘luxury consumption’ of potassium

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031208

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe development of representative salmonellas [Salmonella enteritidis(Gaertner) andSalmonella paratyphi B] and of spore‐forming organisms which resist pasteurization has been studied in synthetic creams. The creams consisted of (a) a vegetable oil emulsified in an aqueous solution of cellulose ethers (‘cellulose ether cream’) and (b) the oil emulsified in a medium containing egg yolk and sodium alginate (‘egg cream’). Rapid growth of the salmonellas to populations of 30–40 × 106cells/g. took place in the egg cream within three days at 18–20°, but practically no growth occurred in the cellulose ether cream. No change in the appearance or odour of the creams was evident. The presence of a heat‐resistant, mixed microflora did not significantly influence the growth of the salmonellas in egg or cellulose ether creams.Growth of the organisms which resisted pasteurization was more rapid in the egg cream than in the cellulose ether cream at 18–20°, and was accompanied by development of putrid odours in the egg cream. No detectable growth took place in either cream after incubation at 1–8° for 22 days.It is recommended that where refrigerated storage is not available, storage periods not exceeding 4–6 days and 3–4 days at 18–20° be adopted for cellulose eth

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031209

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY

摘要:

AbstractThe I : I′‐dianthrimide reagent was tested for determining boron in some plants and soils. A convenient modification of the method of Ellis, Zook&Bandish (1949) is described, permitting the determination of 3 μg. of boron with a standard error of ± 0.48%, using the Biochem absorptio

ISSN:0022-5142    

DOI:10.1002/jsfa.2740031210

出版商:John Wiley&Sons, Ltd    

年代:1952

数据来源: WILEY