摘要:

AbstractThe relationship between soil and plant selenium has been investigated using two75SeO3spiked silt loam soils from the Hoosfield series with long‐term equilibration pH values of 4.5 and 7.Lolium perenneplants were grown in the soils over a 15‐week period, and seven harvests were made. Plant samples and soil solutions were assayed for radioactivity, and selenium compounds found in the soil solutions separated by high voltage paper electrophoresis. Throughout the 15‐week experimental period selenium speciation was observed to change in soil solution. Samples collected at day 2 from pH 4.5 soil revealed that selenate accounted for 71% and selenite 8% of the soluble selenium compounds present, whereas for the pH 7 soil the relative percentages were 51 and 23% respectively. After 105 days selenate accounted for 22% and selenite 20% at pH 4.5, and 12 and 22% respectively at pH 7. The occurrence of selenoglutathione was noted in the soil solution and its concentration increased significantly with time. Statistically significant correlations (r=0.82) were found between the concentration of selenium inLolium perenneat harvest and selenate selenium removed from the soil sol

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350602

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractSeed coated with a formulation containing calcium peroxide slightly improved establishment and yield of winter wheat direct‐drilled in the presence of straw residues compared with wheat seed coated with a commercial fungicide/pesticide. There was no benefit in the presence of stubble or after burning. Even with the peroxide coating the yield of the crop direct‐drilled into chopped straw was 33% less than where the residues had been bu

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350603

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractForty‐six soil samples from cacao plantations located in South‐western Nigeria were analysed for extractable zinc by four methods, namely, ammonium acetate, dilute hydrochloric acid, magnesium chloride and diethylenetriamine pentaacetic acid (DPTA). Guinea corn (sorghum) was grown as a test crop. Relations among soil test methods, plant zinc uptake, and soil properties were examined by simple and multiple correlation analyses. The Zn extracted was in the following order: 1.0NNH4OAc>0.1NHCl>2NMgCl2>0.005MDTPA. The only correlation between extracts that was significant at the 5% level was between NH4OAc and DTPA extractable Zn. No soil properties except iron and aluminium oxide were significantly correlated with soil test values. Silt, clay and silt plus clay were correlated at 5, 5 and 1% respectively with Zn uptake, but pH was not. Zinc uptake by the plant was more closely correlated with 2NMgCl2extractable Zn (r=+0.389) than with 1NNH4OAc extractable Zn (r=+0.291); 0.1NHCl extractable Zn (r=+0.079); or with DTPA extractable Zn (r=+0.220). The best prediction of uptake by plants was observed in multiple regression analyses involving combination of MgCl2extractable Zn, pH, organic matter, and silt plus clay fraction (r=+0.6

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350604

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractA study was made of the rate of degradation of mimosine to 3‐hydroxy‐4(1H)‐pyridone in harvested leucaena leaf under various conditions. Optimum rates of degradation of an aqueous leucaena slurry were at pH 8.0 and 45°C with virtual total loss of mimosine in 10 min. Heating the intact leaf also reduced the mimosine content with the maximum rate of degradation at 70°C. The results have implications for reducing the toxicity of leucaena used for sto

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350605

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractLipids were isolated from the adrenals of non‐pregnant, pregnant and foetal sheep (ca30 days pre‐parturition). The lipid content of the adrenals from the pregnant sheep was higher than that of the other groups, and most of this was accounted for by triacylglycerols. Little difference was observed in the fatty acid compositions of the various lipid classes between the pregnant and non‐pregnant animals. All the lipids of the foetal adrenals contained substantial amounts of the 20:3(n–9) fatty acid, which is often associated with essential fatty acid deficiency, but only the cholesterol ester fraction contained a higher level of polyunsaturated fatty acids than was present in the adult groups. The adrenals of the pregnant sheep contained significant levels of glycerolether diesters and neutral plasmalogens, which were fully characterised, and four unknown components that were tentatively identified as steroidal esters. These components were present at barely detectable levels in the adrenals of non‐pregnant sheep. The triacylglycerols, glycerolether diesters and phosphatidylcholines from each group were, where possible, subjected to stereospecific analysis. The triacylglycerols were distinctive and resembled those of plasma and lymph in structure. The results are discussed in terms of a putative direct role for cholesterol esters in corticosteroi

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350606

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractHulls from Tower canola (TCH), Regent canola (RCH) and soya beans (SBH) were included at 10 or 20% in soya bean meal based diets for rats, to compare the effects of these fibre sources on growth, feed consumption, feed efficiency and dry matter and protein digestibilities. A soya bean meal based control diet and another diet containing a purified fibre source (Alphafloc) at a 10% level, were included for a further comparison. Each of the diets was fed to six rats in a 4‐week feeding trial. The diets gave similar weight gain, feed consumption and feed efficiency values. The control diet had the highest mean coefficient of dry matter digestibility (80.8%) and the 20% SBH and Alphafloc diets had the lowest (72.4 and 72.2%). The canola hull and 10% SBH and Alphafloc diets had intermediate values (73.2–75.0%). There was a highly significant negative correlation between the dietary fibre content and the dry matter digestibility of the diets. The control and Alphafloc diets showed the highest and similar apparent (81.4 and 79.9%) and true (86.8 and 85.3%) digestibility values for dietary protein. The 20% canola and soya bean hull diets showed the lowest apparent (71.4–73.7%) and true (76.9–79.4%) digestibility coefficients. The 10% canola and soya bean hull diets had intermediate apparent and true protein digestibility values (73.2‐75.3 and 78.4–80.6%, respectively). The chemical analysis of the fibre sources showed that Alphafloc had the highest cellulose content (88%) and the lowest lignin content (0.6%), while canola hulls had the lowest cellulose content (25.4–28.4%) and the highest lignin content (26.6–28.9%). Soya bean hulls had intermediate cellulose (50%) and low lignin (1.3%) contents. The results suggest that cellulose did not have a detrimental effect on the dietary protein digestibility but lignin and/or some other undetermined factors in the hulls had an adverse effect on protei

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350607

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350608

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThe use of hydrogen peroxide as an alternative to catalysts in the determination of nitrogen in plant materials has been investigated. Nitrogen determination in leaf, stem and seed samples of chickpea and pigeonpea was carried out by three digestion procedures, using hydrogen peroxide (H2O2digestion) without a catalyst, and with mercury or selenium as catalysts (catalyst digestions). The nitrogen values obtained by the three digestion procedures did not differ significantly from each other when examined by microKjeldahl (MKJ) using mercury as a catalyst, and by a Technicon auto analyser (TAA) using selenium as catalyst. The gradual addition of H2O2, as recommended previously, was found to be unnecessary. In view of the cost and health hazards implicated with the use of mercury and selenium for digestion, the procedure based on H2O2digestion is preferable for large scale N determinations in plant tissue and seed samples of these pulse crops. The results sugest that the H2O2digestion technique can be conveniently adapted for total N analysis in plant tissues and grain samples by either TAA or MKJ method.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350609

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractIn the Thomas–Mitchell method for the assessment of protein quality, metabolic faecal nitrogen (MFN) and endogenous urinary nitrogen (EUN) are used to adjust faecal and urinary N excretion on test diets so that true digestibility (TD) and biological value (BV) can be calculated. Using an experimental technique where the urine and faeces from young growing rats were collected every 2 days for an experimental period of 28 days, trends in the estimation of MFN and in the determination of TD and BV were examined. A diet containing 20 g egg albumen kg−1on an as fed basis (2.85 g N kg−1dry matter) has previously been found to be most applicable for the estimation of EUN. This diet was also found to be appropriate for the estimation of MFN. To examine the effect of a change from anad libitumintake of a stock diet (containing 150 g protein kg−1) to the restricted intake of a test diet (containing 80–100 g protein kg−1) on the determination of TD and BV, three protein sources (egg albumen, casein+1%L‐methionine and soya bean meal) were fed at two levels of intake: 9 and 15 g day−1. The time taken for the faecal N excretion to stablilise was very similar with all diets at both levels of intake. The TD of all three protein sources at both levels of intake increased gradually with increasing lengths of preliminary period. However, this increase was not great, and had little effect on the determination of the BV. Stabilisation of urinary N excretion with the three diets depended on the quality of the protein and the amount fed. This led to variation in BV with lengthening preliminary periods, especially at the lower level of intake. Urinary N excretion, and consequently BV, stabilised most rapidly with the highest quality protein (egg albumen) at the highest level of intake. However, stabilisation of BV with the lowest quality protein (soya bean meal) did not occur until after a preliminary period of 12 days, even at 15 g day−1. This preliminary period is considerably longer than that usually employed, and thus it appears that for many proteins the BV may have been assessed during a period before N retention has

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350610

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractInsoluble bound phenolic acids were analysed by g.l.c. and by h.p.l.c. in eight abraded fractions of barley grain. Vanillic,p‐coumaric, ferulic and diferulic acids were identified in all the fractions. Ferulic andp‐coumaric acids were quantitatively the most important. The outer layers, comprising husks, pericarp, testa and aleurone cells, contained the highest concentrations of total phenolic acids (0.6–0.9%) while their concentrations were considerably lower in the endosperm layers (0.1% or less). Calculated on the basis of the cell wall content in the fractions, the highest concentration of ferulic acid was found in fractions enriched with aleurone cells while the highest concentration ofp‐coumaric acid was found in fractions containing high levels o

ISSN:0022-5142    

DOI:10.1002/jsfa.2740350611

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY