THE RATE OF WATER LOSS FROM GRASS SAMPLES DURING HAY-TYPE CONSERVATION

The loss of water from small bulk samples of five grass species was studied under constant conditions of humidity, temperature and lighting. A logarithmic curve was fitted to the data and the different species compared on the basis of a loss coefficient derived from the fitted curve. The species varied significantly in this aspect; those with high surface-area to dry-weight ratios generally lost water fastest The presence of stem material appeared to increase the rate of water loss considerably. High humidity during drying caused the grasses to lose water more slowly and to retain much more water at equilibrium with the surrounding air. Chemical treatments to speed water loss, using a solvent and a fungal toxin were tested. Both appear to have some promise. Selection for high water loss in grass breeding may also be possible.     

RESPITE--a computer-aided guide to the prevalence of pneumonia in pig herds

An interactive computer-based guide (termed RESPITE) was developed to demonstrate to pig producers the expected level of pneumonia in pig herds which follow specified management practices known to influence the severity of pneumonia problems. A program was used to evaluate the combined effect of known risk factors present in the particular herd on the prevalence of lung lesions in slaughter pigs. The expected prevalence was estimated using formulae that were derived from observations and data in the published literature. Eleven risk factors considered are the number of pigs in the same room, all-in/all-out versus continuous flow of pigs, closed versus open herd, temperature fluctuation ratio, width of the buildings, space allotted per pig, the type of partitions separating adjacent pens, the presence or absence of diarrhoea as a clinical problem, liquid versus solid manure disposal, ascarid control efficiency, and the presence or absence of active Aujeszky's disease in the herd. Each of the factors can be assessed in the farrowing, nursery and grow-finish stages of production and the appropriate observations are entered. The computer uses the data to calculate the expected prevalence of pneumonia in animals leaving that stage of production. Of the pneumonia developing in the farrowing, nursery and grow-finish stages, 90 per cent, 75 per cent and 25 per cent respectively is considered to resolve before slaughter inspection at 100 kg. Adjusting for this degree of resolution, the program then estimates the expected final prevalence of pneumonic lesions in slaughter pigs. Comparison of predictions with slaughterhouse data from four herds indicated that the guide was realistic in its estimates.     

Perinatal piglets under sublethal concentrations of atmospheric carbon monoxide

Perinatal exposure to atmospheric carbon monoxide at sublethal concentrations affected neonatal piglets negatively. Low total hemoglobin concentration and oxyhemoglobin saturation ratio were present at birth in piglets farrowed by gilts that had been exposed to carbon monoxide at 250 ppm from gestation d 109 on, but stillbirth rate was only 4.8%. Carboxyhemoglobin saturation ratio increased from .0 to 19.8 and 22.4% as carbon monoxide concentration rose from background (less than 5 ppm) to 200 and 250 ppm. Carbon monoxide affected neonatal piglets' behavior. Piglets exposed to atmospheric carbon monoxide at 250 ppm perinatally took longer to nurse for the first time than did counterparts under background or 200-ppm concentrations. Those under carbon monoxide at 250 ppm had compromised performance in behavior tests that measured a piglet's ability to orient itself in, maneuver in and investigate its environment, respectively.     

Identification of interleukin-1 in equine osteoarthritic joint effusions

Interleukin-1 (IL-1) is a protein secreted by stimulated cells of the monocyte-macrophage line, which has a number of important biologic activities. Interleukin-1 has been implicated in the induction and augmentation of the pathologic processes involved in arthritis and articular cartilage destruction. Horses develop osteoarthritis with a frequency and degree of severity similar to human beings. To further document the similarity of the osteoarthritic process in people and horses, the synovial fluid from 5 horses with clinical osteoarthritis was tested for IL-1 bioactivity. Interleukin-1 activity was found in all tested synovial fluids. Upon column chromatography, the synovial fluid-derived factor had a molecular weight consistent with that of IL-1 in other mammalian species. Ion exchange chromatography of osteoarthritic synovial fluid revealed the principal peaks of bioactivity to be in the fractions with isoelectric points of 7.2, 5.4, and 4.7, which are characteristic of IL-1. A considerable degree of homology between human and equine IL-1 was demonstrated by the cross hybridization of human IL-1 beta cDNA probe with RNA derived from IL-1-producing equine adherent monocytes. These results indicate that equine IL-1 is in all of the osteoarthritic equine joints tested and that equine IL-1 has many of the characteristics of IL-1 isolated from other species.     

Some effects of off-road vehicles and sheep grazing on lizard populations in the mojave desert

The effects of two environmentally disruptive activities were determined using the numbers and biomass of lizards. Sheep grazing reduces ground cover necessary for some lizard species. The use of vehicles on the desert also eliminates vegetation and adversely affects lizard populations.     

Integrating in situ quantitative geographic information tools and size‐specific,laboratory‐based growth zones in a dynamic river‐mouth estuary

• 1. The ultimate determination of coastal habitat suitability requires the integration of both dynamic (i.e. water mass characteristics) and stationary (structural) habitats. An approach using real‐time streamed data collection, remote sensing, and GIS modelling to compare and contrast seasonal and spatial patterns in these habitat components of the eastern and western distributaries of the lower Pascagoula River estuary is described.
• 2. Structural and dynamic habitat characteristics are described using GIS and integrated with published growth data on juvenile mullet (Mugil spp.) and spot (Leiostomus xanthurus) to reveal zones of accelerated growth. Both mullet and spot had their greatest growth when water temperature and salinity (dynamic habitat) were physiologically optimal. The lack of spatial difference in the dynamic habitat between distributaries resulted in no growth zone differences for both species.
• 3. The integration of the growth zones with the structural habitat component showed that the west distributary, with its greater availability and reduced fragmentation of main channel marsh edge, should provide a greater area of essential fish habitat than the east distributary for juvenile spot, a marsh‐edge associate. Because juvenile mullet are less associated with structural wetland habitat, growth zones and the stationary (structural) habitat were not integrated.
• 4. The approach of integrating real‐time geo‐referenced water quality data with regional fish growth‐rate data is an important step towards a quantitative understanding of the hierarchical nature and inherent variability of dynamic coastal environments. The use of this holistic approach should lead to more effective management of estuarine systems, especially in regard to potential impacts within the estuary's watershed and to its coupling with offshore environments.

Copyright © 2007 John Wiley & Sons, Ltd.     

Intersprout competition in the potato II. Competition for nutrients during pre-emergence growth after planting

Summary The influence of temperature, number of sprouts per tuber and concentration of supplementary inorganic nutrients on sprout growth and intersprout competition for tuber substrates during emergence was investigated in the potato varietyArran Pilot. The rate of sprout growth was found to be a positive function of initial tuber fresh weight. Dry weight data at emergence indicated that individual sprouts on multi-sprout tubers exhibited mutual interference for substrates from the tuber. The intensity of this interference increased with temperature in the range 7 25 C, but interference was reduced, and in some cases eliminated, by supplying inorganic nutrients in the rooting medium. It was concluded that a component of the inorganic nutrient solution used could replace the tuber factor the supply of which limited sprout growth. The effects of temperature and inorganic nutrient concentration on the partitioning of dry matter within the plant are deseribed and diseussed.

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Zusammenfassung Die Einflüsse von Temperatur, ursprünglichem Knollengewicht, der Anzahl Keime pro Knolle und der Konzentration zus?tzlicher anorganischer N?hrstoffe auf das Keimwachstum sowie die Konkurrenz zwischen den Keimen um das Knollensubstrat w?hrend des Auflaufens wurden an der KartoffelsorteArran Pilot untersucht. Ween Knollen in ein n?hrstofffreies Medium gepflanzt wurden (Versuch 1), glich die Auflaufrate der Keime einer positiv linearen Funktion der Temperatur über einen Bereich von 7 C bis 25 C, aber sie war nicht signifikant beeinflusst durch die Zahl der Keime pro Knolle (Tabelle 1 und 2). Die einzelnen Keime von Knollen mit vielen Keimen konkurrierten um das Substrat der Mutterknolle, und die St?rke dieser Interferenz nahm mit steigender Temperatur w?hrend des Auflaufens zu (Abb. 1 und 2). In den Versuchen 2 und 3 wurde die Auflaufzeit durch die Beigabe einer anorganischen Volln?hrl?sung zum Wurzeln?hrboden verkürzt, aber sie wurde nicht signifikant beeinflusst durch die Zahl der Keime pro Knolle (Tabelle 4). Eine Erh?hung der N?hrstoffkonzentration in der anorganischen L?sung hatte eine Erh?hung des durchschnittlichen Trockengewichtes der Keime und des durchschnittlichen Trockengewichtes der Keime pro Knolle beim Auflaufen zur Folge (Abb. 4 und 5). In Versuch 2 setzte die Gabe von anorganischen N?hrstoffen die Intensit?t der Konkurrenz zwischen den Keimen um das Substrat aus der Knolle betr?chtlich herab, was darauf hindeutet, dass ein Bestandteil der verwendeten N?hrl?sung den “Knollenfaktor”, der das Keimwachstum begrenzt, ersetzen k?nnte. Im Versuch 3 dagegen wurde die Interferenz um die Substrate aus der Knolle durch die Konzentration der verwendeten N?hrstoffe nicht beeinflusst. Diese Abweichung zwischen den zwei Versuchen dürfte mit dem unterschiedlichen Grad der Interferenz zwischen den Wurzelsystemen der einzelnen Keime für die Zufuhr der verwendeten N?hrstoffe in Zusammenhang stehen (Tabelle 5). Die Temperatur nach dem Auspflanzen übte einen betr?chtlichen Einfluss auf die Verteilung der Trockensubstanz innerhalb des Stengel-systems aus. Anzahl, L?nge und Trockengewicht der Stolonen pro Keim (Abb. 3) und das Verh?ltnis des Stolonentrockengewichtes zum gesamten Trockengewicht der Stengel (Tabelle 3) waren in umgekehrter Bezichung von der Temperatur abh?ngig, in den Versuchen 1 und 3 stand das Verh?ltnis des Stolonentrockengewichtes zum gesamten Stengelgewicht in umgekehrter Bezichung zur Anzahl Keime pro Knolle: in Versuch 3 war diese Beziehung aber nicht signifikant beeinflusst durch die Konzentration der mineralischen N?hrstoffe. Diese Ergebnisse wiesen darauf hin, dass neben der Temperatur ein spezifischer Faktor in der Mutterknolle auf das Stolonenwachstum einwirkte und dass dieser Faktor nicht durch eine den Knollen zur Verfügung stehende mineralischen N?hrstoffl?sung ersetzt werden kann. In den Versuchen 2 und 3 erweiterte sich das Stengel/Wurzel-Verh?ltnis mit der Erh?hung der Konzentration der verwendeten anorganisehen N?hrstoffe, aber es war nicht signifikant beeinflusst durch die Zahl der Keime pro Knolle.

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Résumé L’auteur a recherché, sur la variété de Pomme de terreArran Pilot, l’influence de la température, du poids initial du tubercule, du nombre de germes par tubercule et de la concentration en éléments nutritifs inorganiques supplémentaires sur la croissance du germe et la compétition entre les germes pour les réserves du tubercule pendant la levée. Quand les tubercules sont plantés dans un milieu dépourvu d’éléments nutritifs (expérience 1), la vitesse d’émergence d’un germe est une fonction linéaire positive de la température dans les limites de 7 C à 25 C mais n’est pas significativement influencéc par le nombre de germes par tubercule (tableau 1 et 2). Les germes des tubercules à plusieurs germes rivalisent individuellement pour les réserves du tubercule-mère et il se révèle que l’intensité de cette interférence s’accro?t avec l’augmentation de la température pendant l’émergence (Fig. 1 et 2). Dans les expériences 2 et 3, le temps d’émergence est réduit par l’application au milieu d’enracinement d’une solution nutritive complète inorganique, mais n’est pas significativement influencé par le nombre de germes par tubercule (Tableau 4). Une augmentation de la concentration en éléments nutritifs inorganiques entra?ne, lors de l’émergence, une augmentation du poids sec moyen d’un germe et une augmentation du poids sec moyen de tous les germes du tubercule (Fig. 4 et 5). Dans l’expérience 2 l’application d’éléments nutritifs inorganiques réduit l’intensité de la compétition entre germes pour les réserves du tubercule, ce qui signifie qu’un composant de la solution nutritive utilisée remplace le facteur du tubercule qui limite la croissance du germe. Cependant, dans l’experience 3, la compétition pour les réserves du tubercule n’est pas influencée par la concentration des éléments nutritifs appliqués. La différence dans les deux expériences peut provenir des différences dans le degré d’interaction entre les systèmes radiculaires des germes individuels pour les approvisionnements en éléments nutritifs appliqués (Tableau 5). La température après plantation exerce une influence considérable sur la répartition de la matière sèche dans le système radiculaire. Le nombre, la longucur et le poids sec de stolons par germe (Fig. 3) et le rapport du poids sec des stolons au poids total sec des germes (Tableau 3) sont des fonctions inverses de la température. Dans les expériences 1 et 3 le rapport poids sec des stolons au poids total des germes est inversément relié au nombre de germes par tubercule, mais dans l’expérience 3 ce rapport n’est pas significativement influencé par la concentration externe des éléments minéraux. Ces résultats indiquent qu’en plus des effets de la température, un facteur spécifique provenant du tubercule-mère influe sur la croissance du stolon, et que ce facteur ne peut être remplacé par un apport externe d’éléments nutritifs minéraux. Dans les expériences 2 et 3 le rapport bourgeon/ racine augmente avec l’accroissement de la concentration en éléments nutritifs inorganiques appliqués mais n’est pas significativement influencé par le nombre de germes par tubercule.

     

Performance of ponderosa pine seedlings under four herbicide regimes in northeast Oregon

The herbicide, hexazinone, was applied four ways over ponderosa pine, 2–0 seedlings planted in northeast Oregon. The four treatments were two broadcast applications, a single broadcast application, a large spot application, and a small spot application. Seedling survival and growth were monitored for five growing seasons. Results indicate that survival more than doubled with either large or small spot applications compared to no application, and either one or two broadcast applications can increase survival an additional 30% over spot applications. Differences in stem volume were substantial, with two broadcast applications yielding more than twice the volume of a single broadcast treatment and more than five times the volume of seedlings treated with spot applications. Trees in small spots were still three times bigger than surviving seedlings in the control. These results are consistent with the concept of competition threshold. Management implications were considered in terms of cost of established seedlings. Although broadcast applications cost more per acre than spot applications, gains in seedling survival, growth and quality offset the additional cost and translate into lower established seedling costs. The cost effectiveness of broadcast applications also may be seen in the elimination of replanting or in-planting requirements and increases in long-term growth potential of the established trees.     

光肩星天牛对干旱胁迫下复叶槭挥发物的嗅觉反应

对干旱胁迫下3a生复叶槭的挥发物进行了鉴定。当复叶槭受到干旱胁迫时，9种化合物释放量升高(包括：丁醇、戊醇、反—2—己烯—1—醛、顺—3—己烯—1—醇、戊醛、戊酸、己醛、己酸、苯乙酮)，而长叶烯释放量降低：复叶槭复水后苯乙酮升高，但其他挥发物释放量降低。通过GC—EAD检测了光肩星天牛对其中某些化合物的触角电位反应，并使用诱捕器和人工合成单体进行了田间生测实验。丁醇、戊醇和顺—3—己烯—1—醇能引起光肩星天牛的触角反应，这一结果在田间实验中得到了证实。这表明干旱胁迫在光肩星天牛选择寄主植物方面起着重要作用。