Inheritance of Aluminum Tolerance and its Effects on Grain Yield and Grain Quality in Oats (Avena Sativa L.)

Summary Aluminum toxicity due to the cation Al⁺³ is a major factor limiting yields in acid soils. Wide genetic variability to aluminum tolerance is found in oat genotypes. The objectives of this study were to determine the number of genes controlling aluminum tolerance in oats and to verify if any detrimental effects were present of the aluminum tolerance genes on grain yield and grain quality in Al⁺³free soils. Aluminum tolerance was estimated as the average regrowth of the main root after exposure to toxic levels of Al⁺³ in a hydroponic solution under controlled conditions. The number of genes controlling that trait was estimated from the distribution of the average root regrowth frequencies in a population of 333 recombinant inbred lines (RIL's) in generations F_5:6 and F_5:7. The effects on grain yield and grain quality were assessed in a subpopulation of 162 RIL's chosen based on their aluminum tolerance response. Aluminum tolerance in the evaluated population was controlled by one dominant major gene with the tolerant genotypes carying Al _a Al _a and the sensitive ones al _a al _a alleles. No detrimental effects of the Al _a allele on grain yield or grain quality were detected.Part of the Master of Science dissertation of the first author     

Time-resolved spectral studies of blue-green fluorescence of artichoke (Cynara cardunculus L. Var. Scolymus) leaves: identification of chlorogenic acid as one of the major fluorophores and age-mediated changes

Synchrotron radiation and the time-correlated single-photon counting technique were used to investigate the spectral and time-resolved characteristics of blue-green fluorescence (BGF) of artichoke leaves. Leaves emitted BGF under ultraviolet (UV) excitation; the abaxial side was much more fluorescent than the adaxial side, and in both cases, the youngest leaves were much more fluorescent than the oldest ones. The BGF of artichoke leaves was dominated by the presence of hydroxycinnamic acids. A decrease in the percentage of BGF attributable to the very short kinetic component (from 42 to 20%), in the shape of the BGF excitation spectra, and chlorogenic acid concentrations indicate that there is a loss of hydroxycinnamic acid with leaf age. Studies on excitation, emission, and synchronized fluorescence spectra of leaves and trichomes and chlorogenic acid contents indicate that chlorogenic acid is one of the main blue-green fluorophores in artichoke leaves. Results of the present study indicate that 20-42% (i.e., the very short kinetic component) of the overall BGF is emitted by chlorogenic acid. Time-resolved BGF measurements could be a means to extract information on chlorogenic acid fluorescence from the overall leaf BGF.     

大豆根构型在玉米/大豆间作系统中的营养作用

 运用根构型不同的大豆品种与玉米进行间作，比较大豆根构型在玉米/大豆间作系统中的营养作用。结果表明，玉米与大豆间作具有明显的间作优势，间作作物的生物量、氮磷含量都显著好于单作。玉米与浅根型大豆品种巴西10号间作，间作优势大于与深根型大豆品种本地2号。说明大豆根构型在玉米/大豆间作系统中具有十分重要的作用。间作系统的氮磷养分竞争比率表明，玉米/大豆这类豆科/禾本科间作组合的优势主要来自对氮的优势性吸收，而玉米与不同基因型大豆间作的优势差异则主要来源于对土壤磷吸收的差异。浅根型大豆品种不仅有利于两种间作作物对土壤磷的吸收，同时还有利于对氮的吸收。     

Morphological variability of Atlantic salmon Salmo salar and brown trout Salmo trutta in different river environments

Abstract – The morphologies of sympatric juvenile Atlantic salmon Salmo salar parr and brown trout Salmo trutta parr were compared between Irish rivers with contrasting hydraulic environments – a high‐gradient and a low‐gradient tributary from the River Barrow catchment, south‐east Ireland and a high‐gradient river from the Burrishoole catchment, west of Ireland. The two catchments differ markedly in mean annual precipitation (849.0 mm year^?1 and 1370.3 mm year^?1 for the Barrow and Burrishoole catchments, respectively). Parr of both species demonstrated morphological variation between and within catchments. Changes in metrics such as pectoral fin length, body depth and body length between and within catchments suggest that hydraulic forces were a major determinant of morphological variation. Both species from the Burrishoole catchment had relatively larger pectoral fins, longer heads, larger eyes and shallower bodies than conspecifics from the Barrow catchment. In rivers subject to frequent rainfall‐driven high discharges, such as those in the Burrishoole catchment, a more fusiform body and head shape coupled with larger pectoral fins may reduce the energetic cost of maintaining position in the water column, as well as increase stability and manoeuvrability. The larger eyes in both parr species in the Burrishoole catchment could further be a response to the lower visibility of the more turbid and peat‐stained waters or to the reduced prey availability. The results of this study demonstrate that local adaptation to flow conditions can yield morphologically distinct populations and that multiple species can exhibit parallel phenotypic responses to changing environmental conditions.     

Recent advances in external skeletal fixation

While the use of external skeletal fixation was once associated with substantial postoperative morbidity, clinical and experimental studies have led to technological advances and modifications in application techniques that have greatly improved the results obtained with this treatment modality. The past decade saw numerous advances in external skeletal fixator implants, components and instrumentation, including improvements in fixation pin design, and the development of new linear external skeletal fixation systems and economical circular external skeletal fixation systems specifically engineered for use in dogs and cats. In addition, a greater understanding of fixator biomechanics and the pathobiology of the bone-fixation pin interface have improved fixator application practices. This article reviews many of the more significant recent advances in external skeletal fixation.     

Oxidative responses in ferret macrophages

Although the basic function of T and B lymphocytes in ferrets has been known for some time, the function of mononuclear phagocytes has not been described in this species. The present study has characterised basic oxidative responses in ferret macrophages, and has investigated the effects of endogenous and exogenous modulators of macrophage function on oxidative capacity in vitro. Macrophages derived from the blood or lungs of ferrets were shown capable of generating the reactive oxygen intermediate (ROI) molecules superoxide and hydrogen peroxide, and secreting a lysosomal enzyme (acid phosphatase), in response to appropriate stimuli. A T cell supernatant (derived from mitogen-stimulated peripheral blood lymphocytes) was able to activate both blood- and lung-derived macrophages for enhanced ROI production, while specific ROI inhibitors (superoxide dismutase and catalase) were able to partially ablate ROI activity. The accumulation of nitrite in culture supernatants, as an indicator for the production of reactive nitrogen intermediates, could not be demonstrated by ferret macrophages derived from either tissue source. In contrast to the enhancing effects of TCS on the oxidative function of blood-derived macrophages, exposure to bacterial LPS caused marked suppression of ROI and lysosomal enzyme production by these cells. Finally, the generation of superoxide anion, following phagocytosis of live or heat-killed Mycobacterium bovis or zymosan, indicated that ROI production in response to phagocytic stimulation was relatively weak in ferret blood-derived macrophages. These results are discussed in relation to the study of immune function in a novel species, and with particular reference to research into tuberculosis (Tb), since ferrets are important wildlife vectors of bovine Tb in New Zealand.     

In vitro effects of osteotomy angle and osteotomy reduction on tibial angulation and rotation during the tibial plateau-leveling osteotomy procedure

OBJECTIVE: To determine the effect of osteotomy angle, reduction technique, and tibial plateau rotation angle on angular and rotational limb deformities. STUDY DESIGN: Geometric comparison using bone models. METHODS: Rotational osteotomies were made in the proximal metaphysis of artificial tibias at 0 degrees, 10 degrees, 20 degrees, -10 degrees, and -20 degrees from perpendicular with respect to either the proximodistal and craniocaudal tibial axes. Negative-numbered angles represented osteotomies made from distal to proximal or caudal to cranial. Changes in tibial angulation and torsion were measured using a 3-dimensional digitizing instrument at tibial plateau rotation angles from 0 degrees to 30 degrees at 5 degrees increments. Two osteotomy reduction techniques were used: complete osteotomy reduction and alignment of the medial cortex. The mean of 5 measurements of torsional and angular tibial deformity for each of the 9 osteotomy orientations in each reduction technique group was obtained. RESULTS: All had increasing angular and rotational deformity as tibial plateau rotation angle increased. In the medially aligned cortex group, all tibias had valgus deformity, and 8 of 9 tibias were internally rotated. In the reduced osteotomy group, minimal angular deformity was seen in tibias with osteotomy variation along the proximodistal axis; however, tibias with osteotomy variation along the craniocaudal axis had angular deformity ranging from 6.0 degrees of varus deformity to 14.3 degrees of valgus deformity. Rotational deformity was affected similarly by osteotomy variation along either axis. Reduction technique had greater affect on angular and rotational deformity than osteotomy angle variation. CLINICAL RELEVANCE: These results suggest that osteotomy reduction may play a greater role in angular and rotational deformity than osteotomy angle, although extreme osteotomy angles should be avoided. To decrease the severity of deformity, we recommend that the osteotomy be made perpendicular to the craniocaudal and proximodistal axes and be completely reduced with less regard for alignment of the medial cortex.