TRANSLOCATION OF AMINOTRIAZOLE AND DALAPON IN AG ROPY RON REPENS (L.) BEAUV.

Summary. Tracer studies using single drops of solutions containing 3–amino-1,2,4–triazole-5–¹⁴C (aminotriazole-¹⁴C) or 2,2–dichloropropionic acid-2–¹⁴C (datapon-¹⁴C) revealed that in couch plants (Agropyron repens (L.) Beauv.) growing under field conditions in the autumn and at the stage where the aerial shoots were 40–50 cm long, both compounds moved in both symplast and apoplast. Dalapon was less mobile in the symplast than aminotriazole and only negligible amounts of dalapon were translocated to the rhizomes. The nodes of the treated shoots appeared to act as barriers to translocation, a phenomenon more pronounced for dalapon than for aminotriazole.
Application to a basal green leaf led to a more uniform distribution of the compounds within plants and rhizomes than when the application was made to the youngest fully-expanded leaf.
In couch plants with aerial shoots 10–15 cm long treated in the stubble, the distribution of both aminotriazole and dalapon was mainly restricted to the treated shoots. Even 15 days after application only trace amounts of radioactivity could be found in the rhizomes and untreated shoots.     

Examination of the consistency of plant traits driving oil yield and quality in short-rotation coppice cultivation of Eucalyptus polybractea

The value of eucalyptus oil for medicinal purposes is based largely on its cineole content. The prime commercial species for cineole production in Australia is Eucalyptus polybractea (blue mallee). Despite the long history of blue mallee harvesting in Australia, there has been little research on the establishment of plantations of the species or on the efficacy of short-rotation coppice cultivation with respect to the consistency of oil yield and quality from rotation to rotation. This study aims to assess if subsequent coppice oil traits reflect sapling traits and if the coppice oil traits under short-rotation cultivation are consistent from one rotation to the next. A trial plantation was established in a key eucalyptus oil harvesting district in Victoria. Firstly, the oil-related traits of 20 saplings harvested 3.5 years after planting were compared with those of their subsequent coppice harvested after 12 months regrowth. Despite the expected differences in total biomass, the oil-related traits of blue mallee saplings were mostly well reflected in their subsequent coppice. Total above ground biomass and foliar oil concentration were significantly related between saplings and coppice, and cineole proportion showed a Pearson's correlation of 0.93 between harvests. Nevertheless, the mean foliar oil concentration in the coppice was 148 mg g⁻¹ dw compared with 107 in the saplings, and the coppice foliage, on average, showed significantly reduced cineole with a mean of 87% in the saplings (maximum of 95.6%) compared to a mean of only 80% in the coppice (maximum of 87.0%). Secondly, the oil traits of 20 coppice plants from one 12-month harvest rotation to the next were compared. Again, total above ground biomass, foliar oil concentration and cineole proportion were significantly related between the harvests, with cineole proportion having a Pearson's correlation of 0.90 between rotations. The coppice between rotations were remarkably consistent in terms of biomass and oil traits and indeed mean coppice cineole yields were 28.6 and 29.7 g in rotations 1 and 2, respectively. The results support the screening of key oil-related traits in saplings for the selection of elite genotypes for plantations, and the use of short-rotation cultivation of the plantations for continued oil harvesting. Furthermore, no relationship was observed between biomass and oil concentration in the blue mallee saplings or coppice, suggesting selection gains in a given key oil trait will not result in losses in another.     

Three different levels of dietary vitamin D3 fed to first-feeding fry of Atlantic salmon (Salmo salar L.): effect on growth, mortality, calcium content and bone formation

Atlantic salmon ( Salmo salar L.) fry were reared on a fishmeal-based diet with three different levels of vitamin D₃ (0.2, 5 and 57 mg vitamin D₃ kg^–1 feed, ww) from first-feeding for 14 weeks. No significant differences were recorded in weight, length, specific growth rate, mortality, or kidney calcium concentration between the different dietary groups. No skeletal malformations or histopathological changes were recorded in any of the dietary groups. These results suggest Atlantic salmon fry to be highly tolerant of megadoses of vitamin D₃ over a limited period of time.     

Biosolids,mycorrhizal fungi and eucalypts for phytostabilization of arsenical sulphidic mine tailings

The effect of the addition of biosolids combined with a native arbuscular mycorrhizal inoculum on growth of a eucalypt (Eucalyptus cladocalyx), and on trace element stabilization of arsenical sulphidic gold mine tailings was tested. A glasshouse trial was established using four substrates: tailings (T); tailings with a layer of topsoil (TS); tailings amended with 100 t ha⁻¹ biosolids (LB), and tailings amended with 500 t ha⁻¹ biosolids (HB). Half of the pots were inoculated with a mixture of Glomus sp. (WUM51–9227), Scutelospora aurigloba (WUM51–53) and Acaulospora laevis (WUM46) culture mix, and others were uninoculated controls. Two seeds per pot were sown. Leaf and stem weights, leaf area and plant height were measured for each plant. Nutrients and trace element concentrations in leaves and stems were determined. Addition of biosolids significantly increased mycorrhizal colonization (both ectomycorrhizal and arbuscular mycorrhizal) in roots. Biosolids clearly increased the very early establishment and growth of the eucalypts. In general, mycorrhizal inoculum increased plant biomass production and nutrient uptake. Trace element concentrations in trees of the biosolid-amended pots were in general high, however, mycorrhizal inoculation could reduce the uptake of toxic elements by plants.     

Associations of Leptin and Pituitary‐Specific Transcription Factor Genes’ Polymorphisms with Reproduction and Production Traits in Dairy Buffalo

This study aimed to detect the genetic variability in Leptin and Pit‐1 genes using polymerase chain reaction–restriction fragment length polymorphism and DNA sequencing also to explore their possible associations with reproductive and productive traits of Egyptian buffaloes. Regarding Leptin gene, three genotypes (AA, AG and GG) were identified with frequency of 0.54, 0.40 and 0.06, respectively, and the genotypes were distributed according to the Hardy–Weinberg equilibrium. Allele A was comparatively higher than G with frequency of 0.74 and 0.26, respectively. For Pit‐1 gene, the association could not be performed due to the monomorphism (BB). The results showed that AA genotypes were found to be superior in most of production and reproduction traits. AA genotypes yielded more milk (2332.34 kg, p = 0.04) with higher fat% (6.10, p = 0.004) and fat yield (155.75 kg, p = 0.06), reach peak milk production at 42.19 days and required 2.19 services for conception in comparison with GG genotypes. Birthweight of animals with AA genotype was lesser than with GG genotype (39.35 and 43.67 kg, p = 0.02, respectively). The days open is numerically better in AA genotype animals (99.35 days), but the difference between the three genotypes was non‐significant. The distinct significant associations reported in this study suggested that Leptin is reputable candidate genetic marker, which might be used to enhance animals’ genetic potential for milk production in conjunction with reproduction.     

Intra-plant variation in cyanogenesis and the continuum of foliar plant defense traits in the rainforest tree Ryparosa kurrangii (Achariaceae)

At the intra-plant level, temporal and spatial variations in plant defense traits can be influenced by resource requirements, defensive priorities and storage opportunities. Across a leaf age gradient, cyanogenic glycoside concentrations in the rainforest understory tree Ryparosa kurrangii B.L. Webber were higher in young expanding leaves than in mature leaves (2.58 and 1.38 mg g(-1), respectively). Moreover, cyanogens, as an effective chemical defense against generalist herbivores, contributed to a defense continuum protecting foliar tissue during leaf development. Chemical (cyanogens and phenolic compounds) and phenological (delayed greening) defense traits protected young leaves, whereas mature leaves were largely protected by physical defense mechanisms (lamina toughness; explained primarily by leaf mass per area). Cyanogen concentration was considerably higher in floral tissue than in foliar tissue and decreased in floral tissue during development. Across contrasting tropical seasons, foliar cyanogenic concentration varied significantly, being highest in the late wet season and lowest during the pre-wet season, the latter coinciding with fruiting and leaf flushing. Cyanogens in R. kurrangii appear to be differentially allocated in a way that maximizes plant fitness but may also act as a store of reduced nitrogen that is remobilized during flowering and leaf flushing.     

Comparative plasma pharmacokinetics of ceftiofur sodium and ceftiofur crystalline‐free acid in neonatal calves

The objective of this study was to compare the plasma pharmacokinetic profile of ceftiofur crystalline‐free acid (CCFA) and ceftiofur sodium in neonatal calves between 4 and 6 days of age. In one group (n = 7), a single dose of CCFA was administered subcutaneously (SQ) at the base of the ear at a dose of 6.6 mg/kg of body weight. In a second group (n = 7), a single dose of ceftiofur sodium was administered SQ in the neck at a dose of 2.2 mg/kg of body weight. Concentrations of desfuroylceftiofur acetamide (DCA) in plasma were determined by HPLC. Median time to maximum DCA concentration was 12 h (range 12–48 h) for CCFA and 1 h (range 1–2 h) for ceftiofur sodium. Median maximum plasma DCA concentration was significantly higher for calves given ceftiofur sodium (5.62 μg/mL; range 4.10–6.91 μg/mL) than for calves given CCFA (3.23 μg/mL; range 2.15–4.13 μg/mL). AUC_0‐∞ and Vd/F were significantly greater for calves given CCFA than for calves given ceftiofur sodium. The median terminal half‐life of DCA in plasma was significantly longer for calves given CCFA (60.6 h; range 43.5–83.4 h) than for calves given ceftiofur sodium (18.1 h; range 16.7–39.7 h). Cl/F was not significantly different between groups. The duration of time median plasma DCA concentrations remained above 2.0 μg/mL was significantly longer in calves that received CCFA (84.6 h; range 48–103 h) as compared to calves that received ceftiofur sodium (21.7 h; range 12.6–33.6 h). Based on the results of this study, CCFA administered SQ at a dose of 6.6 mg/kg in neonatal calves provided plasma concentrations above the therapeutic target of 2 μg/mL for at least 3 days following a single dose. It is important to note that the use of ceftiofur‐containing products is restricted by the FDA and the use of CCFA in veal calves is strictly prohibited.     

Defense chemistry of cyanogenic Eucalyptus cladocalyx seedlings is affected by water supply

Cyanogenesis is a widespread and effective defense mechanism in plants. Published evidence suggests that cyanogenic capacity (i.e., cyanogenic glycoside concentration) is enhanced in response to water stress, although potentially confounding variables preclude a definite conclusion. We used highly cyanogenic Eucalyptus cladocalyx var. nana F. Muell. seedlings grown with varying amounts of water and nitrogen (N) to determine the relationship between cyanogenic capacity and water stress. We also examined whether variation in cyanogenic capacity affects phenolic biosynthesis because both pathways use phenylalanine as a substrate. Cyanogenic capacity in fully expanded leaves increased 70% in response to moderate water stress when N availability was high but only 30% when growth was N-limited. Absolute cyanogenic capacity also increased with increasing N supply. Total phenolics and condensed tannins decreased with increasing N supply, but these compounds were unaffected by water stress. We conclude that, under the influence of water stress, the enhanced demand for phenylalanine for cyanogenic glycoside biosynthesis can be sustained by enhanced shikimate pathway flux without affecting phenolic metabolism.     

Effects of salt stress on ion accumulation and antioxidative enzyme activities of Oryza sativa L. and Echinochloa oryzicola Vasing

The effects of salt stress on physiological factors, such as inorganic ion absorption and antioxidative enzyme activities, of rice ( Oryza sativa L. cv. Anapurna) and Echinochloa oryzicola Vasing were investigated. Although having similar morphology, rice and E. oryzicola possessed considerably different salt-tolerance mechanisms. Echinochloa oryzicola was more salt-tolerant than rice. When exposed to salt stress (100 mmol L⁻¹ sodium chloride, NaCl; six days), E. oryzicola had the ability to limit the accumulation of sodium ions (Na⁺), maintained high potassium ion (K⁺) content and had a constantly higher K⁺/Na⁺ ratio than rice. Rice was not effective in limiting Na⁺ absorption but had a higher antioxidative capacity than E. oryzicola . The constitutive activities of superoxide dismutase (SOD) and catalase of rice were three and five times higher than that of E. oryzicola, respectively. Induced activities of SOD, ascorbate peroxidase and glutathione reductase were also higher in rice than in E. oryzicola . The high antioxidative capacity was one of the tolerance mechanisms used by rice to cope with salt stress. Therefore, the salt tolerant-mechanisms are different between the two plants.