bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of temperature and diet on the water and energy metabolism of growing rabbits
Authors: Jin L. M. , Thomson E. , Farrell D. J. 
Published: March 2009

SUMMARYWater and energy metabolism were measured in six growing female New Zealand White rabbits placed individually in metabolism cages within chambers at 20 or 30 °C and offered a diet high (H) or low (L) in roughage. For water balance measurements, feed intake was higher at 20 °C than at 30 °C; mean water balance of rabbits on diet L was 7 g/day at 20 °C and 36 g/day at 30 °C. Total daily water consumption was 84–96 g/kg body weight (W), and the ratio of free water to feed intake was 1·6:1 at 20 °C and 2·3:1 at 30 °C.Calorimetric measurements showed no differences in energy metabolism of rabbits due to diet or temperature. Metabolizable energy needed for maintenance was 357 kJ/kg W0·75 per day and was used with an efficiency of 0·44 for weight gain.
Differences in barley grain yields as a result of soil variability
Authors: Finke P. A. , Goense D. 
Published: March 2009

SUMMARYField scale variability in the grain yield of barley in 1989 was investigated in 62 field plots in a Dutch polder area, and compared to soil- and simulation-type characteristics. Total grain mass varied between 3409 and 6019 kg/ha, and grain moisture content between 131 and 14·7%. Soil profile descriptions and soil characteristics were used as basic input data for simulations. Soil water flow was simulated at 119 locations with the LEACHM model, for the purpose of quantifying spatial variability in transpiration deficits in the growing season. Both soil- and simulation-type characteristics were translated from point values to spatial averages for the harvested fields, using kriging. Kriged characteristics were correlated with yields, and used to construct transfer functions. Simulated transpiration deficits during sensitive crop development phases showed negative correlations with grain yield. Transfer functions explained at maximum 68·2% of the variance in the yields.
Influence of planting seed tubers with gangrene(Phoma foveata) and of neighbouring healthy, diseased and missing plants on the yield and size of potatoes
Authors: Hide G. A. , Welham S. J. , Read P. J. , Ainsley A. E. 
Published: March 2009

SUMMARYPotato seed tubers infected or not infected with gangrene (Phoma foveata) were planted at Rothatnsted in 1987 to measure the effect of the disease and of neighbouring plants on yield. The experimental design was constructed so that the effect on growth of six adjacent plants (two nearest neighbours in each direction within rows and one nearest neighbour in each direction across rows) could be estimated for each plant. Total yield, ware (> 150 g) yield and tuber number from individual plants were affected most by the disease but also, in decreasing importance, by the two plants on either side within the same row (first neighbours), the two plants adjacent to the first neighbours (second neighbours) and the two adjacent plants in the rows on either side. Yield and tuber numbers increased as the different combinations of neighbouring plants contained increasing proportions of plants from diseased seed and missing plants; plants compensated for decreasing competition. Tuber size distributions showed that numbers of ware tubers decreased with increasing competition whereas numbers of small tubers were less affected. The fitted model was used to predict yields from crops planted with different proportions of diseased or missing seed tubers.
Effect of chronic cold exposure and underfeeding on hind-limb tissue metabolism in pregnant sheep
Authors: Symonds M. E. , Lomax M. A. 
Published: March 2009

SUMMARYMuscle metabolism was studied in pregnant sheep over the final 4 weeks of pregnancy, between January and March 1985 and between December and March 1986, to investigate the effect of (i) chronic cold exposure, induced by shearing pregnant ewes 8 weeks before lambing and (ii) undernutrition in shorn and unshorn ewes. This was achieved by measuring hind-limb tissue metabolism using a combination of isotopic and arterio–venous difference techniques.The rates of blood flow, oxygen uptake, carbon dioxide production and calculated heat production were all significantly higher across the hind-limb tissues in shorn than in unshorn ewes. The increase in hind-limb energy metabolism in the shorn group was such that 65% of the difference in wholebody heat production between shorn and unshorn groups could be attributed to muscle tissue. Following underfeeding, all of the difference in whole-body heat production between the two groups was completely attributable to muscle tissue.Nonesterified fatty acid (NEFA) oxidation by muscle accounted for 46% of the difference in whole-body NEFA oxidation rate between fed shorn and unshorn groups. Underfeeding significantly increased the mean arterial plasma concentration of NEFA in shorn and unshorn ewes and the rate of NEFA oxidation across the hind-limb tissues in shorn ewes. The difference in whole-body NEFA oxidation between shorn and unshorn groups could, therefore, be completely accounted for by muscle. No significant differences in the arterial plasma concentrations of glucose, lactate or 3-hydroxybutyrate were recorded between shorn and unshorn ewes, although the rate of glucose uptake across the hind-limb tissued was significantly higher in the shorn group. Calculation of the maximum potential contribution of these substrates to hind-limb metabolism demonstrated that NEFA were the predominant energy source in all experimental conditions studied in all ewes. When data from fed and underfed shorn ewes were pooled, regression analysis revealed a significant negative correlation between the arterial plasma concentrations of glucose and 3-hydroxybutyrate, and significant positive relationships between the arterial concentrations of both glucose and 3-hydroxybutyrate and their rate of uptake across the hind-limb tissues. These relationsips were not observed in unshorn ewes.It is concluded that the muscle mass plays a major role in the nonshivering thermogenic adaptation to chronic cold exposure in shorn pregnant sheep and that NEFA are the major substrate utilized for oxidative metabolism in this tissue.
Estimation of plant cell wall thickness and cell size by image skeletonization
Authors: Travis A. J. , Murison S. D. , Chesson A. 
Published: March 2009

SUMMARYA system for automatically measuring the mean cell-wall thickness in a user-defined area of plant tissue has been developed using image analysis. The digitized grey-level image of a tissue section is first segmented using a histogram-partitioning algorithm. The resulting binary image is then repeatedly thinned until the minimum connected set of pixels, or ‘skeleton’, remains. A nearestneighbour length estimator is used to calculate the total length of the skeleton which approximates to the location of the middle lamella in the original section. The length of the skeleton and the number of nodes it contains are used to estimate the mean cell radius, and mean cell-wall thickness using the area of cell-wall material in the segmented binary image. The method has been used to estimate mean cell-wall thickness along a newly extendedZea maysinternode, and the results are compared to measurements obtained manually using a micrometer ‘line’. The techniques of rapidly assessing mean cell-wall thickness and cell dimensions using image analysis are needed to assess how much of the variation in nutritive value between forage cultivars can be ascribed to changes in cell-wall chemistry and how much to anatomical differences.
Cross resistance between water and oxidative stresses in wheat leaves
Authors: Pastori G. M. , Trippi V. S. 
Published: March 2009

SUMMARYSeven-day-old leaves of two wheat cultivars, one resistant (Cruz Alta) and one sensitive (Leones) to water stress were subjected to 100% O2 and water stress in the light for 72 h. The aim of this work was to analyse the effects of both types of stress on the chloroplast antioxidant enzymes, glutathione reductase (GR) and ascorbate peroxidase (AP) and their relationship with stress resistance.Both GR and AP increased following 100% O2 and water stress in the resistant cultivar Cruz Alta only. Sulphydryl (SH) groups increased in the resistant cultivar and decreased significantly in the sensitive one under both stress treatments. Measurement of stress parameters (chlorophylls, proteins, lipid peroxidation and conductivity) revealed that oxidations caused by stress treatments appeared to be higher in the sensitive cultivar Leones than in the resistant Cruz Alta.It is suggested that there may be a link between GR, AP and oxidative protection. Some cross resistance between water and oxidative stresses in wheat leaves is also indicated.
Digestion by sheep of silages prepared from mixtures of tropical grasses and legumes
Authors: Tjandraatmadja M. , MacRae I. C. , Norton B. W. 
Published: March 2009

SUMMARYFour silage diets were prepared from tropical grass and legume mixtures and fed to intestinally fistulated sheep to determine the sites and extent of digestion of the different silage components in the digestive tract. Pangola grass (Digitaria decumbens) was ensiled either alone or with the addition, 33% (w/w), of leucaena (Leucaena leucocephala cv. Cunningham), gliricidia (Gliricidia sepium) or cowpea (Vigna unguiculata cv. Caloona). All forages were grown at the University of Queensland farm in 1985. All silages were well preserved as indicated by low pH (< 4·1), ammonia N (< 9% total N), acetic acid (< 13 g/kg dry matter (DM)) and ethanol (< 19 g/kg DM) contents, and high DM (> 290 g/kg) and lactic acid (> 41 g/kg DM) contents. The inclusion of leucaena and gliricidia significantly increased the total N content of the silages. The addition of legumes at ensiling significantly increased rumen ammonia N (pangola 59 mg N/l, legume diets 110–115 mg N/l) and the proportion of propionic acid in rumen fluid. Sheep given pangola + leucaena silages had significantly higher DM intakes (66·3 g/kg W0·75 per day) than sheep given pangola and pangola + cowpea silages (52·4 and 53·2 g/kg W0·75 per day respectively). The inclusion of gliricidia significantly depressed silage intake (43·1 g/kg W0·75 per day). There were no significant effects of diet on DM (551–609 g/kg) and organic matter (550–612 g/rkg) digestibility. Sheep given pangola + leucaena silages had higher N intakes, N balances, rates and efficiencies of microbial N synthesis and total non-ammonia N (NAN) flows to the small intestine than did sheep given the other silages. Apparent degradabilities of silage N in the rumen were similar for all diets (0·491–0·559 g N/kg N intake), but sheep given pangola + leucaena silages had lower true (corrected for endogenous N) N degradabilities (0·648 g N/kg N intake) than those given the other diets (0·751–0·775 g N/kg N intake). The values obtained in this experiment were compared with those reported for temperate grass silages, and it was concluded that whilst the digestibility of tropical grass/legume silages was low, intakes and rumen fermentation characteristics were similar to those found for temperate grass silages.
Grass yield in relation to potassium supply and the concentration of cations in tissue water
Authors: Barraclough P. B. , Leigh R. A. 
Published: March 2009

SUMMARYA long-term field experiment on permanent grass at Rothamsted (UK) was studied between 1988 and 1991 to determine the relationship between soil and plant K and to identify critical soil and plant concentrations for grass yield. Maximum dry matter yield was obtained at a soil exchangeable K concentration (Kex) of 114 mg/kg dry soil (45 μм-K in the soil solution). Grass well-supplied with K maintained an average concentration ofc.200 m м-K in the tissue water of whole shoots in spring, although individual measurements varied in the range 140–320 mм, depending largely on the soil water availability. These tissue concentrations were not exceeded in soils with Kexvalues up to 800 mg/kg. Yield was reduced by 60% on plots low in K (Kexin the range 60–90 mg/kg). The yield reductions were probably due to low turgor because tissue osmotic pressures were low and potassium concentrations in tissue water (which averaged 64 mм) were probably too high to disrupt the biochemical functions of K. The results suggest that there is no universal critical tissue water concentration for K in the biophysical role of turgor maintenance, as other cations and solutes are able to substitute for it. The ultimate determinant of turgor-dependent yield loss is tissue osmotic pressure. The critical tissue osmotic pressure in grass shoots in a typical season at Rothamsted wasc.400 mosm/kg. No universal critical osmotic pressure can be expected however, as this will depend on the availability of water and therefore on growing conditions.
Internodal invertases and stalk maturity in sugarcane
Authors: Sehtiya H. L. , Dendsay J. P. S. , Dhawan A. K. 
Published: March 2009

SUMMARYAcid and neutral invertase activities in the stem of an early (CoJ 64) and a late cultivar (Col 148) of sugarcane were estimated by incubating stem slices in buffered sucrose solution and measuring the production of reducing sugars. High enzyme activity occurred in young tissue but the activity of both enzymes was considerably lower in the mature internodes. Acid and neutral invertase activity was highest in the midinternode position, corresponding to the region of cell expansion.
Effects of subsoiling and associated incorporation of fertilizer on soil rehabilitation after opencast mining for coal
Authors: Scullion J. , Mohammed A. R. A. 
Published: March 2009

SUMMARYA trial was set up in South Wales in 1980 on land replaced in 1972 after opencast coal mining, to assess the effects on soil rehabilitation of regular subsoiling, through an established sward, with and without incorporation of a ‘semi-organic’ fertilizer into subsoiling slots. Treatments were assessed on the basis of yield, soil structure indices, root and organic contents and earthworm population densities. Apart from yields, data are for the eighth year of the experiment (1987), 18 months after the fourth programme of treatments.Treatments did not markedly affect productivity, although it tended to be higher with subsoiling and fertilizer incorporation. Subsoiling had little effect on root and organic content, but fertilizer incorporation increased the latter, particularly at depth. Earthworm population densities were markedly higher on subsoiled areas, the increase in the deeper burrowing speciesAporrectodea caliginosabeing largest. Fertilizer incorporation increased abundance ofLumbricus rubellus, but had little effect on other species. Subsoiling reduced surface wetness, but did not result in any significant improvement in structure. Fertilizer incorporation reduced clay dispersion at depth and, with subsoiling, also increased pore space.Treatment responses in term of soil structure were not large, but the incorporation of fertilizer did markedly accelerate structure rehabilitation at depth. Subsoiling alone contributed to land rehabilitation by controlling surface wetness and encouraging an increase in earthworm populations.
Use of n-alkanes for the estimation of herbage intake in sheep: accuracy and precision of the estimates
Authors: Vulich S. A. , O'Riordan E. G. , Hanrahan J. P. 
Published: March 2009

SUMMARYTwo experiments at Belclare, Co. Galway, in late autumn 1988, evaluated the use of herbage and dosed n-alkanes for estimating herbage intake by sheep. The first experiment examined faecal recoveries of dosed and herbage n-alkanes. The second experiment assessed the accuracy and precision of herbage intake estimates obtained using the n-alkane technique, and tested the effect of supplying n-alkanes to animals either in gelatine. capsules (containing different ratios of n-alkane: cellulose fibre) or in pellets prepared from shredded paper onto which the n-alkanes had been adsorbed. Individually penned wether lambs were offered freshly cut herbage ad libitum (+ 10%) and actual dry matter intake was recorded daily. Intake was estimated using the C31:C32 and C33:C32 (natural:dosed) n-alkane ratios.There was no significant effect of n-alkane chain length on faecal recovery rate for either the dosed n-alkanes (C32 and C36), the herbage odd-chained n-alkanes (C29, C31, C33 and C36) or those used for the estimation of herbage intake (C31, C32 and C33). The accuracy and precision of the n-alkane technique for estimating herbage intake were unaffected by whether the dosed n-alkane was supplied in capsules or pellets or by the n-alkane:cellulose fibre ratio in the capsules. The bias in the estimated intake was – 8% (± 1·1%) and + 3% (± 1·2%) for estimates based on C31:C32 and C33:C32 ratios, respectively. The estimates based on C31:C32 and C33:C32 exhibited similar precision in the estimation of herbage intake, with a R.S.D. of 6% in actual intake when adjusted for variation in estimated intake and a correlation of +0·92 between actual and estimated herbage intake. The C.V. for actual herbage intake was 17%. The repeatability of actual dry matter intake over three consecutive 6-day periods was 0·54 while those of estimated intake were 0·57 and 0·60 for estimates based on C31:C32 and C33:C32, respectively. The results show that the n-alkane technique can provide an accurate and precise estimate of herbage intake.
Controlling manganese deficiency in sugarbeet with foliar sprays
Authors: Last P. J. , Bean K. M. R. 
Published: March 2009

SUMMARYField experiments in 1987 and 1988 on peaty-loam, Mn-deficient soils of the Adventurers series in Cambridgeshire, UK, tested the response of sugarbeet to three forms of manganese fertilizer supplied as foliar sprays. The influence of a wetter and an adjuvant on manganese absorption and growth was also investigated.Cutonic and chelated forms of Mn, when applied at standard rates, were inefficient at increasing Mn concentrations in plants and alleviating deficiency symptoms during early summer. Mn concentrations in foliage increased rapidly after spraying with manganese sulphate, and most of the deficiency symptoms disappeared. These benefits were usually enhanced when manganese sulphate sprays were used with an adjuvant.Averaged over both years, yield without Mn was 8·83 t sugar/ha; the largest yield, 9·56 t/ha, was obtained with manganese sulphate plus adjuvant. Smaller benefits were obtained with the other forms of Mn. The adjuvant, when used with chelated Mn, appeared to depress sugar yields in both years. The likelihood of reducing the number of sprays required to control Mn deficiency on Fen soils was improved by using an adjuvant with manganous sulphate sprays.
In saccodegradation of organic matter and crude protein of fresh grass (Lolium perenne) in the rumen of grazing dairy cows
Authors: van Vuuren A. M. , Tamminga S. , Ketelaar R. S. 
Published: March 2009

SUMMARYIn three experiments, carried out in 1985 and 1986 in the Netherlands, the effects of herbage maturation and rate of nitrogen fertilization on rumen degradability of organic matter (OM) and crude protein (CP) in fresh herbage (Lolium perenne) were studied using the nylon bag technique. Experimental farms at Lelystad and Swifterbant (clay soil) and Achterberg (sandy soil) provided the herbage samples. From the results, the content of digestible CP entering the small intestine (DPI) was estimated.Crude protein content andin saccodegradability of OM and CP decreased with increasing grass maturity and with decreasing rate of N application. With every 100 g/kg DM decrease in CP content, the estimated content of DPI decreased by 19 g/kg DM, no matter how the CP content was manipulated.
Leaf and flower initiation in potato (Solanum tuberosum) sprouts and stems in relation to number of nodes and tuber initiation
Authors: Firman D. M. , O'Brien P. J. , Allen E. J. 
Published: March 2009

SUMMARYExperiments were conducted in controlled environment cabinets and in the field at Cambridge, UK, in 1987–90 and in Valencia, Spain 1989–90 with several varieties of potato. The initiation of leaf primordia and flowers was recorded in sprouts stored for long periods at 13°C with constant illumination and in sprouts exposed to different photoperiods and periods of cold storage. In field experiments, the effects of a wide range of planting dates, differences in physiological age, the time at which seed tubers were sprouted and of imposing an 8 h photoperiod were investigated.More than 40 leaf primordia were initiated in the sprouts of Home Guard and Arran Comet stored at 13 °C, but, in other varieties, fewer leaves were initiated. Flowers were initiated in the sprouts of some varieties. In field-grown plants, the number of nodes to the first flower differed between varieties and was increased by ageing sprouts before planting. Stems from physiologically old seed of all varieties had more nodes below ground than young seed but the number of aerial leaves to the first flower increased only slightly with increasing physiological age. The number of aerial leaves to the first flower was lower and less variable in Estima than in Maris Piper.Initiation of flowers usually occurred before tuber initiation and within two weeks of emergence but was earlier in some varieties than others. There was little influence of photoperiod on the time to initiation of flowers and tubers in most experiments but, with low levels of radiation, flowering was completely inhibited in the variety Maris Piper.
Effect of nitrogen on nodulation and yield of soya beans under two systems of production in Sudan
Authors: Khalifa F. M. 
Published: March 2009

SummaryTwo experiments were run over a 3-year period in the central rainlands of Sudan under two systems of production, rainfed and irrigated, to assess the effects of system of production, inoculation and nitrogen fertilizers on plant and nodule development and grain yield of soya beans. Nodulated plants could fix more than 80 kg N/ha under irrigation whereas under rainfed conditions nodulation was neither effective nor efficient. Soya bean was responsive to nitrogen fertilizers under both systems of production giving significant increments in grain yields. Non-nodulating plants with added nitrogen fertilizers produced more total dry matter than nodulating plants during the vegetative phase until flowering time. At 2 weeks after flowering total dry-matter production for both types was equal and from then on to maturity nodulating plants outyielded non-nodulating ones in total dry-matter production. In 1979 and 1980 yield of irrigated nodulating soya-bean grain was 0·53 and 1·54 t/ha higher than rainfed yields whereas the difference in grain yields of the non-nodulating soya beans was 0·21 t/ha and zero during the same two seasons, respectively. There was a contrasting inverse relation between the number of nodules and dry weights under the two systems of production. Fewer and heavier nodules were produced under irrigation whereas under rainfed conditions nodulation was profuse and nodules were light. On the evidence available 1–4 g/m length of the granular form of soil implant inoculant (Nitragin), i.e. 16·6·66.4 kg/ha, is to be recommended for irrigated soya-bean production in Sudan.