摘要:

AbstractPost‐germination but pre‐emergence waterlogging of winter wheat for 3 days or more, delayed emergence and decreased the final number of plants in two experiments on sandy loam and clay soils in outdoor conditions. Coating seeds with calcium peroxide improved emergence to a small extent, but would appear to offer only a small benefit to establishment of wheat already treated with insecticide/fungicide dressings and sown under normal conditions in the fi

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341102

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effects of the application of fertilisers, especially N and trace elements, on the content of Co in mixed grassland herbage and its main constituent species, have been studied. Data have been obtained from field experiments on three mineral soils and on a deep acid peat. The herbage was cut at the silage stage of growth three or four times a year for at least three successive years. Without added Co, N applications increased Co content in herbage on peat but reduced it on mineral soils mainly by eliminating clover which had a higher Co content than grasses. Applying 0.5 kg ha−1Co as cobalt sulphate increased herbage Co content, the increase being greater on peat than on mineral soils. These increased levels were unaffected by N applications on mineral soils but were further increased by applied N on peat. The number of years during which the Co additions were effective in producing herbage containing at least 0.1 mg Co kg−1dry matter varied on the different soils, ranging from barely three years on one mineral soil to over five years on peat. Without added Co the last cuts in October usually had the highest Co content and the first cuts in June the lowest. With added Co, the seasonal effects were more variable, but the Co content in the herbage frequently decreased from the first to the last c

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341103

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractIt has been shown that the myrosinase activity in rapeseed and in white mustard seeds is similar and does not depend on the variety of rapeseed. The two molecular forms of rapeseed myrosinase with different isoelectric points, Km values towards sinigrin, response to ascorbic acid and stability were isolated. The enzyme was strongly stimulated by ascorbic acid and had the same hydrolytic potential against rapeseed glucosinolates as the myrosinase from white mustard. However, the rapeseed enzyme was much less stable during storage. The fast inactivation of myrosinase in both, flaked and intact seeds was achieved after incubation at 90–100°C and 90–100% relative humidity. In the flaked seeds, however, a substantial amount of the endogenous glucosinolates had already been decomposed before complete inactivation of the enzyme. Thus, it is suggesting that the enzyme should be inactivated in the intact seeds before proces

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341104

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of various assay parameters on in‐vivo nitrate reductase (NR) activity in coconut leaf tissue was studied andn‐propanol was found to inhibit the activity at all levels. The enzyme activity was higher in air than under nitrogen. Addition of NADH to the assay medium did not increase the activity significantly. Light stimulated the activity and the addition of glucose to dark treated leaves did not restore the activity fully. The 14th leaf on the coconut crown is the most appropriate for sampling. The inducible NR activity showed a high positive correlation with annual yi

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341105

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe contents of extractives, starch, crude protein, non‐starch polysaccharides and Klason lignin were determined in red clover harvested at six different stages of maturity. Chemical analysis of residues after incubation with rumen liquorin vitrorevealed that the degradability of starch was 100% and of crude protein about 80% at all harvest times. The degradability of non‐starch polysaccharides decreased from 76 to 51% during maturation and no degradation of Klason lignin was noticed. At all harvest times xylose was the least degraded non‐starch polysaccharide residue followed by glucose and rhamnose. During maturation the greatest decrease in in‐vitro degradability was noticed for the xylose residues followed by the glucose and the mannose r

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341106

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractEight soil tests for plant‐available copper were used on twenty English soils of moderate to low copper status. The ability of these tests to predict plant copper uptake, tested in a pot trial, was compared using multiple regression analysis including other soil factors such as pH, organic matter and clay content.The EDTA soil test was found to give the best prediction of plant uptake from a regression equation including EDTA extractable soil copper, pH, free Mn and Fe oxide, clay and organic matter conten

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341107

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractA survey of extractable copper, lead, zinc and cadmium in Northern Ireland's top soils was carried out to see if the trace element concentrations could be related to the parent material of the soils and to the influence of human activity.Using ordnance‐survey identification, 1305 samples were selected as representative of the soils of Northern Ireland. Duplicate subsamples of each soil were shaken with 0.05M EDTA (pH 7.0) for 60 min and the supernatant analysed for copper, lead, zinc and cadmium by atomic absorption techniques. Ranges and medians for each trace element are recorded and comparisons with results of copper reported for other countries have been identified.Relative distribution diagrams are presented for each of the elements under investigation and computer‐drawn symbol maps have been produced showing the distribution of the concentration of each element in comparison to the parent geology.Finally correlation coefficients between the concentration of each trace element and the ammonium acetate/acetic acid (pH 4.2) extracted phosphorus and potassium have been calculated and used to show that a specific relationship between the extractable trace elements and man's additions to the soil, as indicated by the soil fertility, is poorly develo

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341108

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe effect of 2,4‐dichlorophenoxyacetic acid (2,4‐D) (4 × 10−5M‐4 × 10−3M) on the growth and physiological activity ofStreptococcus lactissubsp.diacetylactisandLactobacillus caseihas been investigated when cultivated in milk and lactose‐peptone media. The concentrations of 2,4‐D applied in milk did not cause complete growth inhibition of any of the strains. The degree of inhibition was dependent upon the bacterium species and the herbicide dose. Growth of the tolerant strain—L. casei W‐10—was reduced by about 40% (in the presence of 4 × 10−3M 2,4‐D), whereas the the level of lactic acid production remained almost unchanged. Under the same conditions, growth of the sensitive strainS. lactissubsp.diacetylactis 239was reduced by almost 25 times and lactic acid production inhibited by about 40% in comparison with the controls. Cultivation ofS. lactissubsp.diacetylactis 239in lactose‐peptone medium with 2 × 10−3M 2,4‐D was characterised by a lengthened lag‐phase, lengthened generation time (3 times) and an increased rate of herbicide metabolism. In addition, selective or mutative action of 2,4‐D has been shown. Herbicide treatment inhibited the cells of c.f.u. producing the least acid and enhanced the contribution of the active ones. Cells of c.f.u. with activities not found in the control population have also been revealed. Both species of bacteria were capable of meta

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341109

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractSultana berries were treated with alkaline oil‐in‐water emulsion by partial or total immersion, spotting or spraying. Their weight loss during dehyration at 40°C and the colour and extent of surface bloom of the resultant raisins were determined. Approximately 37 μl of emulsion adhere to the berry during immersion but about 85% of this accumulates as a run‐off droplet. Spread of emulsion from treated to untreated parts occurs on mature berries only; it increases with increasing maturity, as shown by its linear relationship with the concentration of total soluble solids in the fruit. Comparable amounts of emulsion are more effective when spotted uniformly instead of distally on the berry surface. Drying accelerates as berries receive more spots of emulsion. Approximately 9 μl of emulsion placed by spotting or part‐immersion give raisins of similar quality to that of raisins dried after total immersion, despite slower drying rates during the first 36–48 h of dehydration. Any further reduction in the amount of emulsion leads to slower drying and darker raisins.The spray emitted by the nozzels used contained droplets of 190 or 440 μm mean diameter. Between 0.5 and 1.5 μl of emulsion was applied per berry. Small droplets were about 20% more effective than large ones. The efficacy of the best spraying treatment, 1.5 μl berry−1and small droplet size, was almost as good as that of immersion.It is concluded that the efficacy of emulsion treatment depends in part on the characteristics of the fruit to be dried. Comparisons between treatments should only be made from several measurements during the course of drying. The cost of drying may be reduced and the quality of the raisins may improve when the emulsion treatment is modified according to the type of Sultana

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341110

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractQuantitative analysis of each of the S‐alk(en)yl‐L‐cysteine sulphoxides was achieved by the following procedure. A methanol: chloroform: water extract of onion tissue was purified by electrophoresis. Alk(en)yl‐L‐cysteine sulphoxides were separated by thin‐layer chromatography (t.l.c.) on commercial silica‐gel plates and were reacted with ninhydrin, the spot intensity being measured by an integrating densitometer. The synthetic analogue (±)‐S‐1‐butyl‐L‐cysteine sulphoxide was used as an internal standard in each extract.In white bulb onion (cv. Southport White Globe), (±)‐S‐1‐propyl‐L‐cysteine sulphoxide is the predominant flavour precursor at a concentration of 2.9 ± 0.4 mg g−1fresh weight. ±‐S‐1‐methyl‐L‐cysteine sulphoxide and (±)trans‐S‐1‐propenyl‐L‐cysteine sulphoxide are present at the lower concentrations of 0.9 ± 0.25 mg g−1fresh weight and 0.6 ± 0.15 mg g−1fresh weight respectively.Stable n‐butyl, trifluoroacetyl derivatives of standards and of the alk(en)yl‐L‐cysteine sulphoxides in extracts, were formed. Subsequent g.c.‐m.s. enabled parent ions and fragmentation patterns to be recorded and allowed the co

ISSN:0022-5142    

DOI:10.1002/jsfa.2740341111

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY