摘要:

AbstractThe factors that affect gum formation in stone‐fruit trees share the common feature of stimulating ethylene production in plant tissues. It is suggested that ethylene might play an important role in gummosis. The chemical structure of the exudate gums is similar to that of certain cell‐wall polysaccharides and it is possible that gummosis is caused by excessive formation of these polysaccharides as a result of ethylene production in the tiss

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340102

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe total amounts of C14–C32and their composition in the free and anionic state (fatty acid soaps) in the diet, entering and leaving the small intestine and excreted in the faeces were determined in sheep fed white clover or white clover plus corn oil. Only small amounts of fatty acid soaps were found in the digesta entering the small intestine while the hind gut was the major site of soap formation as 66‐73% of the faecal fatty acids were present as fatty acid soaps. In the digesta and faeces the distributions of the C14and C32, expressed as a percentage of the total fatty acids, within the free and anionic states were similar. In contrast to the C14–C18fatty acids no significant apparent absorption of the C19–C32fatty acids o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340103

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractDepression of percentage emergence of vegetable seedlings was linearly related to the quantity of nitrogen fertiliser applied when the fertiliser was broadcast and worked into the seed bed. Placement of fertiliser at a depth of 8 cm avoided depression of emergence. The extent to which emergence was affected depended on the weather, and on the crop, some species (e.g. lettuce) being sensitive, others (e.g. red beet) being resistant to the effects of nitrogen fertilisers. A computer program was used to calculate the effects of rainfall, evaporation and soil temperatures on the concentration of nitrate in the top 5 cm of soil in a series of 45 field experiments, and this was compared with the seedling emergence records. According to the program this concentration varied widely over short periods. Red beet and radish achieved a high percentage emergence after very brief periods of low nitrate concentration. For most crops, however, transient short periods of low nitrate concentration were insufficient for satisfactory emergence, and most crops exposed to high nitrate concentrations, even if these were not continuous, suffered some reduction of emergence. Spinach was able to resist a high concentration of nitrate during the 3 days after sowing, but not at later periods. The sensitivity of crops varied, and the period of sensitivity was also different for different crops. Methods of application of nitrogen fertilisers likely to avoid depression of seedling emergence are briefly discussed.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340104

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractDimethyl disulphide (DMDS), the main cause of brassica anaemia in ruminant animals, was determined in the blood of steers ingesting S‐methylcysteine sulphoxide (SMCO) present in leafy brassicas. Blood samples were treated with Zn and dilute phosphoric acid and the DMDS reduced to methanethiol which was determined by gas chromatography headspace analysis. DMDS levels increased as the intake of SMCO with the brassicas progressed. They were maximal at the haemolytic crisis; thereafter, with the appearance of young red cells or reticulocytes, they declined sharply, but again increased as the new cells matured. The distribution of DMDS was; red cell 85%, plasma 15%. The distribution reached equilibriumin vitroin about 2

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340105

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractCell walls of barley straw (whole sample and stem), Italian ryegrass (shoot) and lucerne (mature stem) were treated sequentially with NaOH followed by a commercial ‘cellulase’ preparation and, in other experiments, with the cellulase followed by the alkali. The phenolic compounds released by NaOH were determined and related to increases in the degradability of the walls as measured with cellulase. Two sequential treatments of the cell walls of barley straw increased degradability from 11% on treatment with cellulase alone to 87%, compared with increases from 72 to 99% and from 19 to 54% for the ryegrass and lucerne walls respectively. The first alkali treatment released ferulic andp‐coumaric acids from the walls of barley and ryegrass together with other u.v. absorbing compounds, whereas the compounds released by the second alkali treatment did not include these two acids. The treatment with alkali did not release either ferulic acid orp‐coumaric acid from the walls of lucerne and the amounts of other u.v. absorbing compounds that were released were much

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340106

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe excretion of the coccidiostats sulphaquinoxaline and decoquinate has been studied in caged broilers on diets containing 100 and 30 mg kg−1of the drugs respectively. Sulphaquinoxaline reached a maximum excretion of 54 mg kg−1(based on dried excreta) in 18 days and decoquinate a level of 37 mg kg−1after 14 days. When the drugs were withdrawn from the feed the excreta concentration decreased to less than 2 mg kg−1in 3 days. Storage of contaminated excreta at 23°C for 9 days showed contrasting effects; the sulphaquinoxaline content decreased from 56 to 35 mg kg−1whereas the decoquinate concentration increased from 37 to 41 mg kg−1. Both coccidiostats appeared relatively stable when samples of excreta were dried in layers 1 cm thick in an o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340107

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340108

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340109

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractAcetone:water (3:1) extracts of milled barley grains contained simple monomeric, dimeric and trimeric flavanols in addition to higher molecular weight flavanoid tannins. Whereas (+)‐catechin and the simple individual oligomeric proanthocyanidins were readily separated by h.p.l.c. and t.l.c. fine resolution of the tanning components was not accomplished. Adsorption chromatography on Sephadex LH‐20 permitted group separation and measurement of tanning components which were characterised as polymers of (+)‐catechin and (+)‐gallocatechin. Using h.p.l.c. little change in the contents of simple flavanols was detected during the malting of barley, neither were there substantial differences in flavanol contents between five different varieties of barley. The tannins appeared to be formed in the grain prior to harvesting, possibly by oxidation of simple flavanols, and were not artefacts of post‐extraction t

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340110

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe bitterness associated with certain cultivars of Brussels sprouts has been shown to be linked to the presence of the glucosinolates, sinigrin and progoitrin. Whereas the former compound is bitter per se, the bitterness associated with the latter compound is due to its decomposition product, the goitrogen (‐)5‐vinyloxazolidine‐2‐thione. A method is described for the screening of cultivars of this, and other, Brassica vegetables for potential bit

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340111

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY