bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of radiation and nitrogen on number of grains in wheat
Authors: Abbate P. E. , Andrade F. H. , Culot J. P. 
Published: March 2009

SUMMARYThe possible interacting effects of shading and N supply on number of grains ofTriticum aestivumL. (cv. Buck Ñandú) were investigated at Balcarce, Argentina, during the 1988/89 and 1989/90 growing seasons. Shading was imposed fromc.13 days before anthesis to 6 days after, and four rates of N fertilization were supplied within each shading treatment around the date of terminal spikelet formation. Water and other nutrients were not limiting.Total grain yield was strongly correlated with grain number/m2, regardless of shading or N supply. At the highest N rates, grain number and dry weight of spikes at anthesis were linearly related to a photothermal quotient, i.e. the ratio of intercepted photosynthetically active radiation (PAR) to mean temperature minus 4·5 °C, during the period from 20 days before anthesis to 10 days after. The response of grain number to the photothermal quotient was interpreted in terms of the supply of assimilates to the spike at anthesis, which determined flower survival. The response of dry weight of spikes to photothermal quotient was interpreted in terms of crop growth rate since there was a linear relationship between crop growth rate and intercepted radiation. The lowest N rates reduced the number of grains/m2, at any given photothermal quotient. Since the reduction in grain number also occurred at any given dry weight of spikes, it cannot be explained by a reduced supply of assimilates to the spikes. Grain number responded directly to the supply of N to the spike, probably through the survival of differentiated flowers. The relationship between spike growth rate and crop growth rate was not affected by N supply. Crop growth rate was reduced by reduced N supply, because less radiation was intercepted and because radiation-use efficiency was lowered. These results indicate that current models for determining yield and number of grains/m2, based on crop growth, are not adequate when N is deficient.
Sugarbeet seedling growth from germination to first leaf stage
Authors: Durr C. , Boiffin J. 
Published: March 2009

SUMMARYThe growth of sugarbeet (Beta vulgaris L.) seedlings was investigated under laboratory conditions in 1990 and 1991. Three phases were identified during heterotrophic growth in the dark, based on the changes in dry weight, carbon and nitrogen contents. The perispermic reserves were first transferred to the young seedling. All the components of the seedling (cotyledons, hypocotyl, radicle) began to elongate and their dry weights increased. The seedling separated from the seed at the end of this first period, 4 days after imbibition had started at 20 °C. During the second period, there was a major redistribution of material between organs, mainly from cotyledons to the hypocotyl. The different organs elongated rapidly. From the start of the third period, 6 days after sowing at 20 °C, the organs began to lose weight and gradually ceased to elongate. The dry weights of the whole seedlings and of each organ were proportional to the initial seed weights. The elongations and changes in dry weights obtained at different temperatures coincided when time was expressed as thermal time using a base temperature of 3·5 °C. The growth of the seedling after illumination depended on the heterotrophic growth duration. If emergence occurred after 100 °Cd, the relative growth rate of the seedling decreased. In field conditions, plant variability at the end of sugarbeet establishment is due not only to variations in seed weights but also to environmental conditions that control emergence delay.
Edge effects on yield, yield components and other physiological characteristics in cereals and oilseed crops
Authors: Hadjichristodoulou A. 
Published: March 2009

SUMMARYThe edge effect (calculated as the mean of the two outer rows as a percentage of the mean of the four central rows of 6-row plots) was measured in ten comparative trials conducted in Cyprus during 1987–90, with two cultivars each of rapeseed, safflower and sunflower, and one cultivar each of barley and durum wheat. Grain, straw and total biological yields obtained from the outer rows were usually higher than those obtained from the central rows by 1–384%. In one trial with sunflower, the grain yield of the outer rows was only 64% of that of the central rows, which could not be explained, considering all the other data. Differences in edge effects between species and trials were significant. Grain yield estimated from the central rows was on average 53% of that estimated from whole plots, and this varied with species and season. Therefore, in comparative trials, the outer rows should be removed before harvesting. There was no significant edge effect on the oil content of the oilseed crops. Edge effects on harvest index, volume weight, 1000-grain weight and nitrogen content were generally smaller than those on yield, and on average ranged from 100 to 113, thus the values computed from the outer rows were only 0–13% higher than from the central rows.
Effect of species composition and sward structure on dietary quality in cattle and sheep grazing South African sourveld
Authors: O'Reagain P. J. , Owen-Smith R. N. 
Published: March 2009

SUMMARYThe effect of sward structure and species composition on dietary quality in cattle and sheep grazing a mesic, low quality grassland (sourveld) in South Africa was investigated over the 1990/91 and 1991/92 grazing seasons. Species composition had no measurable effect on dietary quality in either cattle or sheep but this variable could affect quality over grazing periods longer than those used in the study. In contrast, sward structure, and in particular sward greenness, had a major effect on dietary quality in both animals. Dietaryin vitrodigestibility (IVD) was positively correlated (P< 0·001) with sward greenness but negatively correlated (P< 0·05) with herbage mass and sward height. Dietary IVD in sheep was consistently higher (P< 0·001) then in cattle but both species reacted in a similar manner to changes in sward structure and season. Dietary quality declined over the grazing season, with IVD being highest in spring (> 60%) and lowest in winter (< 45%). Marked intra-seasonal fluctuations in quality also occurred in response to sward structure and apparent variation in soil moisture. Fire also appeared to have a significant effect on quality, with IVD being higher (P< 0·001) in the first year following the burn than in the subsequent year. It is suggested that on sourveld, dietary quality in the growing season is determined by a combination of environmental and management factors. Conversely, in the dormant season, dietary quality is largely determined by environmental factors beyond the control of the grazier.
Laboratory study of the availability of nutrients in physical fractions of cattle slurry
Authors: Díaz-Fierros F. , Villar M. Carmen , Gil F. , Leirós M. Carmen , Carballas M. , Carballas Tarsy , Cabaneiro Ana 
Published: March 2009

SummaryThe characteristics of three fractions obtained by physical separation from each of 19 cattle slurries are reported, with the aim of investigating their behaviour in the soil. The fraction retained on a 1 mm sieve (F1) was the poorest in nutrient content. The fraction passing through a 1 mm sieve but retained in Richard's apparatus on a cellulose membrane of 2·4 nm pore radius (F2) contains most of the slurry's organic N and Pand most divalent cations (Ca2+ and Mg2+). F3, which passes through the cellulose membrane, contains most of the slurry's inorganic N and most monovalent cations.The individual fractions are both chemically and physically much more homogeneous than the slurry as a whole, and their relative proportions are well correlated with the slurry's density and dry-matter content (P < 0·001), so that this kind of fractionation may confidently be expected to provide an analytical scheme facilitating research on the behaviour of slurry after its application to soil.
Effect of nitrogen and phosphorus on the production potential of pearl millet–cow pea or green gram intercropping systems under rainfed conditions
Authors: Kaushik S. K. , Gautam R. C. 
Published: March 2009

SummaryResults are described of an experiment involving various pearl millet–cow pea or green gram planting and interplanting systems under four levels of nitrogen and two levels of phosphorus. Planting of pearl millet in paired rows of 30 and 70 cm gave as much yield as normal planting in uniform rows of 50 cm. The productivity per unit area was increased considerably when pearl millet was interplanted with one row of cow pea or green gram. Cow pea gave higher yield than green gram. Nitrogen fertilizer increased pearl millet as well as intercrops yield significantly. Pearl millet responded up to 60 kg N/ha and intercrops up to 30 kg N/ha. Phosphorus fertilizer did not produce marked improvement in either growth or yield of pearl millet. Application of 40 kg P2O5/ha increased grain yield of intercrops significantly
Effect of green manuring and mineral fertilizer on growth and yield of crops in rice-based cropping on acid lateritic soil
Authors: Sharma A. R. , Mittra B. N. 
Published: March 2009

SummaryGreen manuring in situ with sunnhemp (Crotalaria juncea) and dhaincha (Sesbania aculeata) significantly improved growth and yield of transplanted rice. Giving the green manure crops 15 kg N/ha or 15 kg N and 30 kg P2O5/ha further increased yield. Interaction between green manuring and N fertilizer revealed that a considerable quantity of fertilizer N (45–60 kg N/ha) applied to rice could be replaced by incorporation of green manure crops to which a small amount of fertilizer had been applied. Residual fertility in terms of organic carbon and available N, P and K increased under green manuring, whereas N fertilizer made no impact on fertility build up. Grain yield of wheat and gram increased when grown after rice in plots which had grown green manure.
Growth and gastrointestinal nematode parasitism in lambs grazing either lucerne (Medicago sativa) or sulla (Hedysarum coronarium) which contains condensed tannins
Authors: Niezen J. H. , Waghorn T. S. , Charleston W. A. G. , Waghorn G. C. 
Published: March 2009

SUMMARYTwo grazing experiments were undertaken to evaluate the effects of sulla (Hedysarum coronarium) which contains condensed tannins (CT) and lucerne (Medicago sativa), which does not contain CT, on the performance of parasitized and non-parasitized lambs. The work was carried out near Palmerston North, New Zealand in 1992 and 1993.Experiment 1 used lambs which were either genetically ‘conventional’ or ‘resistant’ to gastrointestinal nematodes and which had a naturally acquired heavy parasite burden (faecal egg count (FEC) 1300–2500 eggs per gram faeces (epg)). They were either drenched to remove all the parasites or remained undrenched when allocated to pure swards of either sulla or lucerne for the 28-day experimental period. Liveweight gains of drenched lambs were higher with sulla (mean 302 g/day) than with lucerne (mean 245 g/day; P < 0·02) and rates of gain were not reduced (P = 0·10) by genetic resistance to nematodes. Undrenched lambs had mean faecal egg counts of 1090–2220 epg after 28 days, with higher counts in lambs grazing lucerne than in those grazing sulla (P < 0·05). Lambs grazing lucerne also had a much lower average daily gain (ADG) (mean 50 g/day) than those grazing sulla (mean 206 g/day; P < 0·0001). Resistant lambs had reduced (P = 0·07) ADG in the sulla treatment only.In Expt 2, lambs with a relatively low worm burden (average FEC 250 epg) were either drenched to remove all worms or dosed with 20 000 Trichostrongylus colubriformis infective larvae and grazed on pure sulla or lucerne swards for 42 days. Drenched lambs had a similar liveweight gain (mean 190 g/day) and wool growth when grazing either sulla or lucerne. Undrenched lambs grazing sulla had a greater ADG (mean 129 g/day) than those grazing lucerne (mean −39 g/day; P < 0·0001) and a higher rate of wool growth from mid-side patches (P < 0·009) and larger wool fibre diameter (P < 0·05) than those grazing lucerne. Undrenched lambs grazing sulla had lower FECs (P < 0·05) on days 14, 21, 35 and 42 than those grazing lucerne and lower (P < 0·05) Trichostrongylus colubriformis worm burdens at slaughter. Undrenched lambs had less perineal faecal contamination when grazing sulla rather than lucerne. Parasite-induced anorexia was evident in the lambs grazing lucerne but not in those grazing sulla.These findings demonstrate that the performance of lambs infected with nematode parasites can vary substantially when given feeds of a similar chemical composition. The superior performance of lambs grazing sulla was probably caused by condensed tannins, which decrease protein degradation in the rumen and can increase post-ruminal protein availability.
The effect of rate, form and timing of fertilizer N on nitrogen uptake and grain N content in spring malting barley
Authors: McTaggart I. P. , Smith K. A. 
Published: March 2009

SUMMARYField experiments were carried out on six sites in eastern Scotland between 1987 and 1989 to determine the effect of nitrogen on the yield, N uptake and grain N concentration of spring barley grown for malting. The effects of fertilizer applications at rates from 0 to 150 kg N ha-1and the timing of application were studied, using three fertilizer forms: calcium nitrate, ammonium sulphate and ammonium nitrate. Calcium nitrate applications significantly increased grain N concentrations (P< 0·05), and grain yields (P< 0·01 and 0·05) at two sites, above the values obtained with the other fertilizers, but there was no effect at the other sites. Split applications of calcium nitrate increased yields above those from single applications in some treatments at two sites. At low rates, recovery of15N-labelled fertilizer was greatest when applied as calcium nitrate. Recovery fell at higher rates in calcium nitrate treatments, but rose in ammonium sulphate treatments. Uptake of fertilizer N, during the period of stem elongation in June, was significantly greater (P< 0·05) in the calcium nitrate and ammonium nitrate treatments. Maximum uptake was usually reached by the time of anthesis. Uptake of soil N was not as great during the early sampling periods, but continued up to harvest in most treatments. There was evidence of losses, between anthesis and harvest, of fertilizer N previously taken up by the crop. The uptake of soil N remained constant over the range of fertilizer treatments except with ammonium sulphate, where there was evidence of increased uptake at higher fertilizer rates, possibly due to ‘pool substitution’ of15N-labelled fertilizer. The variation in soil N uptake between sites was greater than the variation in fertilizer N uptake caused by different forms of fertilizer and different application times.
A reassessment of the part played by rapid intracellular ice formation in producing frost damage in the field
Authors: Habeshaw D. 
Published: March 2009

SUMMARYObservations made on freezing tissue show that the appearance of extracellular freezing can occur in tissues which have been initially frozen intracellularly. Since the evidence for the assumption that intracellular freezing is of rare occurrence in the field is based on the microscopical observation of ‘naturally’ frozen tissue it can no longer be assumed that this process is unconnected with the survival of plants overwintering in the field.
Soil compaction in permanent pasture and its amelioration by slitting
Authors: Davies A. , Adams W. A. , Wilman D. 
Published: March 2009

SUMMARYIn a field which had been grazed by dairy cows for 26 years, the bulk density of both total soil and fine earth increased rapidly with depth down to 10–12 cm, but decreased below this depth. The bulk density was approximately twice as great in the 10–12 cm as in the 2–4 cm layer. Total porosity in the 10–12 cm layer was only 22%.Slitting the soil to penetrate the compacted layer approximately doubled net herbage accumulation and the net uptake of N, P and K, raising herbage production and uptake of nutrients from a low level to an acceptable one. Slitting tended to increase the concentrations of nitrate-N and K in herbage, but had little effect on the concentration of total N. Slitting increased the weight of ash-free root in the 10–20 cm depth range.
Plant height and width inheritance and their correlation with some of the yield components in chickpeas (Cicer arietinum L.)
Authors: Khosh-Khui M. , Niknejad M. 
Published: March 2009

SUMMARYTwo chickpea pure lines, one being short and wide in stature and the other tall and narrow, were crossed. Parents, F1 and F2 generations were grown in the field to study the inheritance of plant dimensions, as well as their correlation with seed yield. Heritability, in broad sense, for plant height and width was 36 and 20% respectively. Estimated minimum number of genes for plant height was two and for plant width was three pairs of genes. Plant height showed correlation values of 0·43 and -0·67 with yield of seed and 1000 seed weight respectively. There were no significant correlations between plant width and the same two yield components.
Studies in the physical properties of soil. V. The hysteresis effect in capillary properties, and the modes of moisture distribution associated therewith
Authors: Haines William B. 
Published: March 2009

A recapitulation of the main features of the moisture distribution in an ideal soil is given in order to emphasise a point previously neglected, namely, that the changes are not in the main strictly reversible, but fall into two series corresponding to the two directions of moisture change. The cellular nature of the soil pore space imposes a quantum character on the moisture changes over a great part of the higher moisture range. The individual cell does not fill or empty by smooth reversible changes but shows two unstable stages at which filling or emptying is completed at a bound. For falling moisture the suction level is that at which a meniscus can invade a cell through one of its narrow entries, which gives a value in the neighbourhood of 12 T/r for close packing. For rising moisture the suction level is that for which water returns to the cell by the collapse of a bubble in it, giving a lower value in the neighbourhood of 6·9 T/r. A still lower value of 4·5 T/r can be reached for a particular type of distribution confined to the lower moisture range.All the above suction values are closely verified by measurements made with bronze balls and paraffin oil. A detailed exploration of the case for glistening dew and water has been made, which verifies the theory while illustrating more nearly the behaviour of an irregular soil. The two values which rule the two halves of the “hysteresis loop” for this case of natural or common packing are 6·0 T/r for falling moisture and 4·0 T/r for rising.The new considerations resolve the differences of opinion raised by R. A. Fisher. It appears that the author has throughout supported a case which belongs correctly to the falling moisture series. Fisher considered a very limited series for the rising moisture case and a hypothetical reversible series, and has been in error in so far as his treatment was regarded as exclusive.
Making Friends at Court: Slow and Indirect Media in US Public Diplomacy in Norway, 1950–1965
Authors: DANIELSEN HELGE 
Published: March 2009

AbstractThis article explores why slow and indirect media were regarded as particularly appropriate means in the US public diplomacy efforts towards Norway in the period 1950–65. The article traces how these strategies were carried out in practice by using as examples exchange programmes and the setting up of American Studies in Norway. The Norwegian case is seen in relation to similar efforts elsewhere, and the article discusses whether this case should be seen as a singular one or as a local variation of more general US public diplomacy strategies. In conclusion, it is suggested that the Norwegian case appears to be an almost ideal-typical example of how ‘culturalist’ public diplomacy approaches were mobilised for political purposes.
The relationship between international humanitarian law and human rights law from the perspective of a human rights treaty body
Authors: Hampson Françoise J. 
Published: March 2009

AbstractThe debate about the simultaneous applicability of international humanitarian law and human rights law also affects human rights treaty bodies. The article first considers the difficulty for a human rights body in determining whether international humanitarian law is applicable; second, it examines the problems in practice in applying thelex specialisdoctrine and the question of derogation in this particular context. The author finally outlines the impact of the debate as to the extent of extraterritorial applicability of human rights law.: : : : : : :
The Mechanisms Involved in Seed Dormancy Alleviation by Hydrogen Cyanide Unravel the Role of Reactive Oxygen Species as Key Factors of Cellular Signaling during Germination
Authors: Oracz Krystyna , El-Maarouf-Bouteau Hayat , Kranner Ilse , Bogatek Renata , Corbineau Françoise , Bailly Christophe 
Published: March 2009

AbstractThe physiological dormancy of sunflower (Helianthus annuus) embryos can be overcome during dry storage (after-ripening) or by applying exogenous ethylene or hydrogen cyanide (HCN) during imbibition. The aim of this work was to provide a comprehensive model, based on oxidative signaling by reactive oxygen species (ROS), for explaining the cellular mode of action of HCN in dormancy alleviation. Beneficial HCN effect on germination of dormant embryos is associated with a marked increase in hydrogen peroxide and superoxide anion generation in the embryonic axes. It is mimicked by the ROS-generating compounds methylviologen and menadione but suppressed by ROS scavengers. This increase results from an inhibition of catalase and superoxide dismutase activities and also involves activation of NADPH oxidase. However, it is not related to lipid reserve degradation or gluconeogenesis and not associated with marked changes in the cellular redox status controlled by the glutathione/glutathione disulfide couple. The expression of genes related to ROS production (NADPHox, POX, AO1, and AO2) and signaling (MAPK6, Ser/ThrPK, CaM, and PTP) is differentially affected by dormancy alleviation either during after-ripening or by HCN treatment, and the effect of cyanide on gene expression is likely to be mediated by ROS. It is also demonstrated that HCN and ROS both activate similarly ERF1, a component of the ethylene signaling pathway. We propose that ROS play a key role in the control of sunflower seed germination and are second messengers of cyanide in seed dormancy release.
RNAi‐mediated resistance to Potato spindle tuber viroid in transgenic tomato expressing a viroid hairpin RNA construct
Authors: SCHWIND NORA , ZWIEBEL MICHÈLE , ITAYA ASUKA , DING BIAO , WANG MING‐BO , KRCZAL GABI , WASSENEGGER MICHAEL 
Published: March 2009

SUMMARYBecause of their highly ordered structure, mature viroid RNA molecules are assumed to be resistant to degradation by RNA interference (RNAi). In this article, we report that transgenic tomato plants expressing a hairpin RNA (hpRNA) construct derived from Potato spindle tuber viroid (PSTVd) sequences exhibit resistance to PSTVd infection. Resistance seems to be correlated with high‐level accumulation of hpRNA‐derived short interfering RNAs (siRNAs) in the plant. Thus, although small RNAs produced by infecting viroids [small RNAs of PSTVd (srPSTVds)] do not silence viroid RNAs efficiently to prevent their replication, hpRNA‐derived siRNAs (hp‐siRNAs) appear to effectively target the mature viroid RNA. Genomic mapping of the hp‐siRNAs revealed an unequal distribution of 21‐ and 24‐nucleotide siRNAs of both (+)‐ and (–)‐strand polarities along the PSTVd genome. These data suggest that RNAi can be employed to engineer plants for viroid resistance, as has been well established for viruses.