摘要:

AbstractSampling of cereal foods from bulk samples for analyses of nutrients is a well‐known procedure, but a satisfactory sampling scheme for such analyses from breeding and agronomic trials has not been defined. However, selection of five plants from each experimental plot is a common procedure among agricultural scientists. The validity of using grains from such a sample for analysis of protein was tested in the present investigation. Values obtained by analysis of pooled samples of five randomly selected ear‐heads or the average values of five such ear‐heads were not significantly different from those obtained by analyses of sampled aliquots from net

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370302

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractIn a pot experiment sugar beetBeta vulgarisL. ssp.vulgaris, cv. Kawetina, was grown on alluvial soil (21 mg exchangeable K 100 g−1) containing 0 (K1), 20 (K2), 40 (K3) and 60mg fertiliser K 100 g−1soil (K4). The plants were sown on 15 March 1983 and harvested on 23 June, 14 July and 30 August 1983. At final harvest root dry weight/plant had reached 269 g in K1and between 304 and 310 g in K2‐K4. Sucrose values were 15% (K1) and 17.3–17.7% of root fresh weight (K2‐K4) respectively. The osmotic potential of the storage root decreased with increasing K nutrition and time. At final harvest ψ, was between −1.83 (K1) and −2.26 MPa (K4), 75–79% thereof being contributed by sucrose. Sucrose concentrations in press sap increased from 340–400 mM on 23 June to 475 (K1) and 540–570 mM (K2‐K4) at the end of August. In the same period K concentrations declined from 40–100 to 10–35 mM K+. The sucrose, K and Mg concentrations measured in the press sap were lower than those calculated from sucrose, K, Mg and moisture content of the storage root. This indicates that press sap from thawed storage root tissue is not fully representative. Betaine, analysed only at final harvest, significantly increased with increasing K concentrations in the storage root (r=0.83) and a significant linear regression was found between betaine and sucrose accumulation (r=0.57). This is consistent with the role of betaine as a cytosolic osmoticum for sugar beet storage tissue. Other solutes in the cytosol may also contribute to osmoregulation as sucrose a

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370303

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractWheat straw collected from the soil surface 9 weeks after the 1983 grain harvest contained the plant hormone abscisic acid (ABA). A 10 cm3leachate from 1 g of straw is calculated to have contained sufficient ABA (1.5x10−4mol m−3) to retard seedling root extension. In contrast, straw incorporated into surface soil shortly after harvest contained no detectable ABA 9 weeks after harvest. The concentration of ABA in the flag leaf increased during the 2 weeks before grain harvest in 1984. In this particularly wet autumn, ABA in surface straw decreased steadily to below the level of detection 7 weeks after grain harvest. Sephadex chromato‐graphed fractions of aqueous extracts of fresh straw judged to contain ABA inhibited root extension of barley seedlings. These findings indicate causes of poor growth of cereal seedlings drilled into seed‐beds with surface straw residues from the precedi

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370304

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractData are presented on the chemical analysis of oilseeds and their associated impurities. These data are used to support a discussion of the way different impurities components are currently considered. In particular, it is noted that the oil and free fatty acid contents of shell and fines should be carefully taken into account.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370305

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractCalibrations have been developed for the prediction of moisture (34–71% w/w) and bulk density (193–402 g litre−1) in milled peat. Predictive accuracy was satisfactory in the case of moisture (residual standard deviation (r.s.d.)=1.1) but less so for bulk density (r.s.d.=15.1); values for precision (pooled standard deviation between duplicates) were 0.7 and 12.1 respectively. Variations in milled peat colour had no effect on the accuracy of either calibration although variation in sample temperature (+6 to +27°C) resulted in an increased residual standard deviation and the appearance of a small mean bias; precision was also af

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370306

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370307

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThirty‐five Large White x Landrace sows were housed in individual stalls during gestation and were fed a standard diet (DE, 13.2 MJ kg−1) supplemented with oat hulls (OH), such that the ratios of basal diet to OH were 1:0, 9:1, 7:3 or 1:1. Digestibility and balance measurements were made during 7‐day periods beginning on days 45 and 90 of gestation. During a 3‐week lactation all sows were fed a standard diet (calculated DE, 12.5 MJ kg−1, CP, 152 g kg−1). Increasing OH intake increased mean net maternal weight gains and P2 fat depths during pregnancy and tended to increase total litter weight at birth. Sow‐milk solids content and litter weight gain during the 3‐week suckling period also tended to increase (nonsignificant), following increasing OH supplementation during gestation. Increasing OH intake tended to increase VFA and reduce cholesterol concentration in blood plasma at 56 days of gestation. The time taken to consume the once‐daily feed allowance increased and gastrointestinal transit time decreased as OH intake increased. The apparent digestibilities of the major nutrients were significantly depressed with increasing levels of OH in the diet but the total amounts of nutrients absorbed increased. The following values were calculated for OH by the difference method: apparent digestibility of DM, 0.31; apparent digestibility of ADF, 0.17; DE, 6.25 MJ kg

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370308

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractInterrelationships between the concentrations of total condensed tannin (TCT), free condensed tannin (FCT) and lignin were studied to gain knowledge of how to manipulate nutritive value of fresh herbages containing condensed tannins fed to ruminants. FCT was defined as condensed tannin not bound by macerates of fresh plants, with both FCT and TCT being determined with vanillin HCl. Effects of spraying lotus with polyethylene glycol (mol. wt 3350; PEG) upon the relationship between FCT and TCT was also studied. Increasing soil nutrient and climatic stress caused large and similar increases in the concentrations of TCT and of lignin. Over the range 0–90 g kg−1DM, 10% of TCT inLotussp. was detected as FCT, with increments in TCT above 90 g kg−1DM being released almost entirely as FCT. PEG formed much stronger chemical bonds with condensed tannins than did plant proteins, and did not release FCT; consequently PEG application reduced the concentration of condensed tannin that was detectable with vanillin HCl. After disintegration of plant material, it is proposed that most condensed tannin is bound and co‐precipitated as an insoluble complex with protein, that FCT is in equilibrium with this complex, and that bound and free tannin are indices of nutritionally beneficial and detrimental effects produced by condensed tannins in fresh forages eaten by ruminants. It was concluded that growingLotus pedunculatusunder conditions of stress leads to depressions in nutritive value through simultaneously increasing concentrations of lignin and FCT, both of which depress rumen carbohydrate digestion and voluntary intake, and that treatment with PEG offers a convenient method of separating effects due to condensed tannins from other factors influencing nutritiv

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370309

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe following are summaries of the papers presented at a meeting of the Agriculture Group of the Society of Chemical Industry held on 19 March 1985, at the Society of Chemical Industry, 14–15 Belgrave Square, London SW1X 8PS. The papers published here are entirely the responsibility of the authors and do not reflect the views of the Editorial Board of the Journal of the Science of Food and Agricultur

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370310

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractTwo standard titrimetric procedures for determination of free fatty acids in vegetable oils and in oils extracted from oilseeds were examined using rapeseed oil, illipe nuts and fat, and groundnuts and groundnut oil as test materials. Both procedures involve dissolution of the fat in an organic solvent and titration with standard alkali solution using phenolphthalein as indicator. Results obtained using each of the two methods agree closely in most cases and certainly for commercial contractual purposes the two methods are interchangeable. Suggestions are made for modification of these methods particularly in regard to solvents and allowed variation in analysis results.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740370311

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY