摘要:

AbstractTime‐course changes in the structural and physiological properties of sorghum grain embryo have been investigated in relation to the hydrolysis of the endosperm during germination and seedling growth. Histochemical analysis showed that the reserve food materials of the scutellum tissue were metabolised rapidly during germination and seedling growth. Light microscope analysis of structural changes showed that scutellar epithelial cell elongation was associated with endosperm reserve mobilisation. Electron microscope studies verified preliminary histochemical and light microscope findings and showed that extensive metabolism of subcellular storage materials occurred during early germination and seedling growth. Physiological evidence indicated that both sorghum embryo and endosperm were insensitive to the gibberellic acid, GA3. Other hormones such as indole‐3‐acetic acid and kinetin also failed to induce α‐amylase production. This suggests that the hormonal response of the aleurone of sorghum is different from that of barley aleurone. Dissection of sorghum showed that the whole body of the scutellum was capable of producing

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340202

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe ileal digestibilities of dry matter (DM), nitrogen (N), energy and amino acids were measured using pigs prepared with either re‐entrant or simple ileal cannulae and fed a basal wheat diet, a wheat/lupin diet and a wheat/meat and bone meal (MBM) diet. The same pigs were also used to determine the faecal digestibilities of DM, N and energy in these diets. Addition of lupins to the basal diet had no significant effect on the true digestibilities of amino acids but addition of MBM significantly (<0.01) reduced amino acid digestibility. It was calculated that an average of about 90% of the amino acids in lupin and wheat but only 65% of those in MBM were absorbed from the stomach and small intestine of the pig. Compared to lupin and wheat, a much larger proportion of the protein in MBM disappeared in the large intestine (approximately 4, 6 and 15% respectively). On the other hand, a large proportion of the energy in lupins but little of that in wheat and MBM (32, 8 and 4% respectively) disappeared in the large intestine. There were no significant differences between the re‐entrant and simple cannulae for ileal digestibility values of DM, N and amino ac

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340203

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractPollution ofterra rossasoils from the Karst near Trieste by atmospheric lead from automobile exhaust gases is considered as a function of the distance from the source, an isolated straight road. The asymptotic decrease in lead concentration in soil with the distance on both sides of the road is empirically described by means of an intrinsically linear exponential function. The parameters (asymptote and curvature) of the function are first evaluated by linear regression with the linearised function, and then determined by a nonlinear regression program. The application of this model function allows an evaluation of the asymptotic lead concentration. Statistical analysis shows that fitting improves if lead concentration is referred to on a CaCO3‐free basis, because the calcareous grains fromterra rossa<1 mm‐samples contain only traces (<2 μg−1) of metal. The effect of prevailing winds is also dis

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340204

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractCell wall material from the mature stems of perennial ryegrass (Lolium perenne) was hydrolysed with a commercial cellulase preparation. The residual insoluble material was fractionated by treatment with sodium hydroxide, sodium borohydride and mild trifluoroacetic acid and the carbohydrate and phenolic composition of the resultant fractions were compared with those of the original cell wall material. The susceptibility of the cell wall components to solubilisation by these treatments was found to depend more on their association with each other than on their intrinsic properties. These observations are discussed in relation to the concept of the secondary cell walls of plants as networks of cellulose microfibrils embedded in a ligno‐hemicellulose matri

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340205

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractClostridial activity and nitrate‐reduction during ensiling were monitored in laboratory experiments. Wilted and unwilted grass with different amounts of natural or added nitrate were ensiled. Nitrate, probably by its reduction products nitrite and nitric oxide, prevented clostridial growth during the phase of acidification. In nitrate‐free grass clostridial activity started immediately after ensiling. When ensiling nitrate‐containing grass clostridia did not grow as long as nitrate was pr

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340206

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractThe objectives of this study were to establish factors influencing the absorption, excretion and hydrolysis of vicine and convicine in chicks. Blood vicine, following the oral administration of a single dosage of vicine into the crop of young chicks, reached maximum concentrations within 3 h. It was nearly completely removed from the blood within 12 h and had a half‐life of approximately 4.5 h. The accumulation and excretion patterns of vicine in the liver and kidney were similar to those of the blood except that the concentrations were much higher in these tissues, particularly the kidney. Bile also contained a very high concentration of vicine which tended to accumulate following the decline in other tissues. These results together with the appearance of vicine in the urine of colostomised birds suggest that vicine is excreted in the urine and bile. Convicine in contrast to vicine was not absorbed by the chick. In‐vitro studies were carried out with tissue and digesta homogenates from the chick in order to establish the site(s) at which vicine and convicine were hydrolysed to their aglycone forms. The results demonstrated that neither vicine nor convicine were hydrolysed in the presence of liver, kidney, intestinal wall or caecal wall homogenates, digesta from the large intestine or by enzymes present in whole or ground fababeans. They were, however, slowly hydrolysed in the presence of 0.1N HCl at 37°C and very rapidly hydrolysed by digesta from the caeca. Antibiotic additions to the diets markedly reduced the in‐vitro rate of hydrolysis of these compounds. The latter results suggest that vicine and convicine are hydrolysed by microorganisms in the caeca of the chick but are not hydrolysed by the micro‐organisms in the gastrointestinal tract, by endogenous tissue enzymes or by enzymes present in fababeans and only minimally hydrolysed by the low pH of the

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340207

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

Abstract1,4‐Dimethylnaphthalene, carvone [2‐methyl‐5‐(1‐methylethenyl)‐2‐cyclohexene‐1‐one], pulegone [5‐methyl‐2‐(1‐methylethylidene) cyclohexanone]and citral (3,7‐dimethyl‐2,6‐octadienal) were applied as liquids on an alumina solid carrier to samples of potato tubers stored in boxes. The headspace concentrations of the chemicals were related to the degree of growth regulation found in this and earlier solid carrier application experiments and were compared to studies using constant vapour concentration applications which had been conducted previously by other workers. Headspace concentrations of all four chemicals increased with increasing application rates indicating non‐ideal behaviour. Pulegone (100 mg kg−1), carvone (100 mg kg−1) and citral (100 and 500 mg kg−1) did not prevent sprouting. Headspace concentrations of these treatments were less than the constant vapour concentrations previously shown to inhibit sprouting. Pulegone (500 mg kg−1) and carvone (500 mg kg−1) successfully inhibited sprouting. Initial headspace concentrations of these treatments were within the constant vapour concentration range previously shown to prevent sprouting. Headspace concentrations of all four chemicals decreased during the 14‐week treatment period. Headspace concentrations of 1,4‐dimethylnaphthalene, when applied at the recommended solid carrier application rate of 100 mg kg−1were within the constant vapour concentration range previously shown to prevent sprouting. Headspace concentrations of 1,4‐dimethylnaphthalene between 3 and 6 mg m3would be necessary if the chemical were to be successfully applied as a vapour. For these experiments a gas chromatographic (g.c.) analytical method using porous polymer adsorbents was developed. The meth

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340208

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractLow‐resolution proton magnetic resonance (p.m.r.) has been investigated as a rapid screening method for the determination of rubber in guayule. Regression equations have been derived relating p.m.r. measurements to rubber content in the original material and in acetone extracted material, and to the amount of rubber extracted. Linear relationships have been established for all three variables withr2values of 0.92, 0.94 and 0.92 (P<0.001) respectively. Sample pretreatment was found to be important, with grinding and heating resulting in a loss of rubber, as determined by both p.m.r. and extractio

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340209

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractA Neotec Scanning Infrared Analyser was used to generate predictive equations for the rapid estimation of kale digestibility. The most successful of these equations gave estimates of digestibility of samples in a calibration population that correlated highly (r=0.95) with the manual estimates. When this method was applied to additional kale samples, not included in the calibration set, it was again successful in screening for high digestibility, despite lower correlation coefficients and increases in standard errors as compared to the equivalent results for the calibration set. Absorption peaks in the spectral scans of cell wall components were compared with the wavelengths used in the best prediction equation in an attempt to gain a clearer understanding of the factor or factors that limit kale digestibility.

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340210

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY

摘要:

AbstractNeutral volatiles present in the air of a mushroom house during the spawn running phase of commercial production of the mushroomAgaricus bisporushave been identified and their source has been investigated. A group of polychloroanisoles emanated from broiler‐house sweepings used in making wheat straw‐chicken manure compost. Most of the straw volatiles were lost during the process of composting. With certain exceptions, most of the volatiles identified were metabolic products ofA. bisporus, but the source of some cyclic monoterpenoids remains uncertain. Preliminary information suggests that someA. bisporusC8aliphatic alcohols and ketones are attractive to gravid females of the phoridMegaselia halter

ISSN:0022-5142    

DOI:10.1002/jsfa.2740340211

出版商:John Wiley&Sons, Ltd    

年代:1983

数据来源: WILEY