Effect of Foliar Application of Phosphorus on Winter Wheat Grain Yield,Phosphorus Uptake,and Use Efficiency

ABSTRACT

One would expect foliar applied phosphorus (P) to have higher use efficiencies than when applied to the soil, but limited information is available concerning this. Experiments were conducted in 2002, 2003, and 2004 to determine the effect of foliar applications of P on winter wheat grain yields, P uptake, and use efficiency. Twelve treatments containing varying foliar P rates (0, 1, 2, and 4 kg ha^{? 1} in 2002 and 2003 and additional 8, 12, 16, and 20 kg ha^{? 1} in 2004) with and without pre-plant rates of 30 kg ha^{? 1} were evaluated. Foliar applications of P at Feekes 7 generally increased grain yields and P uptake versus no foliar P. Use efficiency was higher when P was applied at Feekes 10.54. Results from this study suggested that low rates of foliar applied P might correct mid-season P deficiency in winter wheat, and that might result in higher P use efficiencies.     

Lethal critical body residues as measures of Cd,Pb, and Zn bioavailability and toxicity in the earthworm<Emphasis Type="Italic">Eisenia fetida</Emphasis>

Background. Earthworm heavy metal concentrations (critical body residues, CBRs) may be the most relevant measures of heavy metal bioavailability in soils and may be linkable to toxic effects in order to better assess soil ecotoxicity. However, as earthworms possess physiological mechanisms to secrete and/or sequester absorbed metals as toxicologically inactive forms, total earthworm metal concentrations may not relate well with toxicity. Objective  The objectives of this research were to: i) develop LD₅₀s (total earthworm metal concentration associated with 50% mortality) for Cd, Pb, and Zn; ii) evaluate the LD₅₀ for Zn in a lethal Zn-smelter soil; iii) evaluate the lethal mixture toxicity of Cd, Pb, and Zn using earthworm metal concentrations and the toxic unit (TU) approach; and iv) evaluate total and fractionated earthworm concentrations as indicators of sublethal exposure. Methods  Earthworms (Eisenia fetida (Savigny)) were exposed to artificial soils spiked with Cd, Pb, Zn, and a Cd-Pb-Zn equitoxic mixture to estimate lethal CBRs and mixture toxicity. To evaluate the CBR developed for Zn, earthworms were also exposed to Zn-contaminated field soils receiving three different remediation treatments. Earthworm metal concentrations were measured using a procedure devised to isolate toxicologically active metal burdens via separation into cytosolic and pellet fractions. Results and Discussion  Lethal CBRs inducing 50% mortality (LD₅₀, 95% CI) were calculated to be 5.72 (3.54-7.31), 3.33 (2.97-3.69), and 8.19 (4.78-11.6) mmol/kg for Cd, Pb, and Zn, respectively. Zn concentrations of dead earthworms exposed to a lethal remediated Zn-smelter soil were 3-fold above the LD₅₀ for Zn and comparable to earthworm concentrations in lethal Zn-spiked artificial soils, despite a 14-fold difference in total soil Zn concentration between lethal field and artificial soils. An evaluation of the acute mixture toxicity of Cd, Pb, and Zn in artificial soils using the Toxic Unit (TU) approach revealed an LD₅₀ (95% CI) of 0.99 (0.57-1.41) TU, indicating additive toxicity. Conclusions  Total Cd, Pb, and Zn concentrations in earthworms were good indicators of lethal metal exposure, and enabled the calculation at LD₅₀s for lethality. The Zn-LD₅₀ developed in artificial soil was applicable to earthworms exposed to remediated Zn-smelter soil, despite a 14-fold difference in total soil Zn concentrations. Mixture toxicity evaluated using LD₅₀s from each single metal test indicated additive mixture toxicity among Cd, Pb, and Zn. Fractionation of earth worm tissues into cytosolic and pellet digests yielded mixed results for detecting differences in exposure at the sublethal level Recommendation and Outlook  CBRs are useful in describing acute Cd, Pb, and Zn toxicity in earthworms, but linking sublethal exposure to total and/or fractionated residues may be more difficult. More research on detoxification, regulation, and tissue and subcellular partitioning of heavy metals in earthworms and other invertebrates is needed to establish the link between body residue and sublethal exposure and toxicity. Keywords: Bioavailability; Cd; critical body residues; earthworms; metals; Pb; soil; Zn An erratum to this article is available at .     

Honey as a protective agent against lipid oxidation in ground turkey.

Lipid oxidation is a major deteriorative factor in meats. Sources of natural antioxidants that are as effective as commercially available antioxidants are desired. The objective of this research was to investigate honey as an inhibitor of lipid oxidation in ground poultry. The antioxidant content of different varieties of honey was investigated spectrophotometrically and honey's effectiveness in reducing oxidation of ground poultry determined by monitoring thiobarbituric acid reactive substances (TBARS). Buckwheat honey had the highest antioxidant content and acacia honey the lowest. Honeys of different floral sources differed in their protection against lipid oxidation. Buckwheat honey (5%, w/w) reduced TBARS approximately 70%, whereas acacia honey reduced TBARS approximately 34% at 3 days of storage at 4 degrees C. In comparison to butylated hydroxytoluene and tocopherol (0.02% of total fat), honey (at 5% of the weight of the meat) was much more effective at preventing oxidation. Honey has great potential as an antioxidant source and may result in greater acceptability of meat products and prevent negative health implications of oxidized meats.     

Growth response of Ficus benjamina to limited soil volume and soil dilution in a skeletal soil container study

The interactive effects of rooting volume and nutrient availability in a skeletal soil medium designed to meet street tree and pavement needs were observed in a containerized experiment. Benjamin fig (Ficus benjamina L.) was grown in a stone-soil blended skeletal soil material (CU-Soil™) and compared to a loam soil. The same topsoil used as the soil component in the skeletal soil material was used as the sole component in the comparison soil-only treatment.Plants grown in the skeletal soil material had reduced leaf tissue N content and depressed growth compared with plants grown in non-diluted soil. No other mineral deficiencies were found. Leaf number, chlorophyll concentration, shoot weight, and root characteristics were all affected.Reduced growth from soil dilution could be offset by the provision of an enlarged rooting volume for root development. Large containers of skeletal soil were observed to have smaller root systems compared to equivalent net volumes of loam soil at the first two harvest dates of the study. By the end of the study, the large containers of skeletal soil were observed to have developed larger root systems compared to equivalent net volumes of loam soil; resulting in comparable leaf N levels and total plant dry matter. Plants in skeletal soil had lower shoot: root ratios at the end of the study. Investing resources to further root growth in times of nutrient shortages is a probable plant reaction as evidenced by differences in specific root length between treatments. The study allowed a method for directly partitioning the containerization effect by having equivalent amounts of soil over two volumes.     

Closed fluoroscopic-assisted spinal arch external skeletal fixation for the stabilization of vertebral column injuries in five dogs

Objective— To evaluate outcome after closed fluoroscopic-assisted application of spinal arch external skeletal fixators in dogs with vertebral column injuries.
Study Design— Retrospective case series.
Animals— Dogs with traumatic vertebral column injuries (n=5).
Methods— Medical records of dogs with vertebral column fractures and/or luxations stabilized with spinal arch external skeletal fixator frames applied using a closed fluoroscopic-assisted technique were reviewed. Owners were contacted to obtain long-term clinical outcomes.
Results— Five dogs (age range, 6–72 months; weight, 10–54 kg) had traumatic vertebral column injuries stabilized with spinal arch external skeletal fixators applied in closed fashion. Injuries involved vertebral segments of the thoracolumbar junction, lumbar spine, and lumbosacral junction. Immediately postoperatively, 4 dogs had anatomic alignment of their vertebral fracture/luxation; 1 dog had 1 mm of vertebral canal height compromise. Time to fixator removal ranged from 65 to 282 days (141±87 days). All dogs had regained satisfactory neurologic function by 3 months. At long-term follow-up (range, 282–780 days; mean 445±190 days) all dogs were judged to have good to excellent return of function by their owners.
Conclusion— Successful closed fluoroscopic-assisted application of external skeletal fixators using spinal arches provided satisfactory reduction with few complications in 5 dogs. Return to function was judged to be good to excellent in all dogs at long-term evaluation.
Clinical Relevance— Closed fluoroscopic-assisted application of ESF using spinal arches provided satisfactory reduction and effective stabilization of spinal fractures with few complications and should be considered as a treatment approach.     

Sesame oleosin and prepro-2S albumin expressed as a fusion polypeptide in transgenic rice were split, processed and separately assembled into oil bodies and protein bodies

A recombinant polypeptide containing the precursor protein of a sesame storage protein, 2S albumin, fused to the C-terminus of a sesame oleosin was expressed in transgenic rice seeds under the control of a rice glutelin promoter. The recombinant polypeptide of 32 kDa, equivalent to the resultant molecular mass of sesame oleosin (15 kDa) and prepro-2S albumin (17 kDa), was detected in the endoplasmic reticulum fraction of maturing transgenic rice seeds, but not in the purified oil bodies or the soluble extract of transgenic seeds. However, sesame oleosin presumably fused with a 2 kDa C-terminal appendix originating from the signal sequence of prepro-2S albumin, was found in the purified oil bodies, and mature sesame 2S albumin apparently processed into two subunits (9 and 4 kDa) linked by disulfide bonds was detected in extracts of transgenic seeds. Immunogold labeling revealed that the sesame oleosin and 2S albumin were separately located in oil bodies and protein bodies of embryo cells of transgenic rice seeds. While sesame 2S albumin was also detected in protein bodies of endosperm cells of transgenic seeds, the co-expressed sesame oleosin, probably degraded due to the lack of oil bodies in this tissue, and was not detected. The results provide a new technique for introducing two recombinant polypeptides separately into rice oil bodies and protein bodies from one expression construct.     

Evaluation of main-crop stubble height on ratoon rice growth and development

Rice (Oryza sativa L.) ratooning is the production of a second rice crop from the stubble left behind after the main-crop harvest. Lowering the main-crop stubble height by harvesting the main crop at a lower than traditional height is believed to alter growth parameters and increase ratoon yields. The objectives of this study were to evaluate the effect of main-crop stubble height on ratoon grain yield, agronomics, and cumulative/weekly panicle growth parameters (density, point of origin, and weight). Main-crop ‘Cocodrie’ and ‘Trenasse’ rice cultivars were harvested to leave either a 40- or 20-cm stubble height. When the main-crop stubble was harvested at 20 cm, ratoon rice grain yield in 2007 was increased by 375 and 190 kg ha⁻¹ for Cocodrie and Trenasse, respectively. Yield was not improved in 2006 using the low (20 cm) harvest height. The yield advantage in 2007 was associated with the increased weight of the basal panicles when the main crop was harvested at 20 cm. When the main-crop stubble was 20 cm, basal and axial panicle points of origin were numerically similar 5 weeks after main-crop harvest (WAH), while panicles originating from basal nodes were predominant 6 WAH and beyond. In contrast, when the main-crop stubble was 40 cm, approximately 75% of the emerged panicles originated from axial nodes 5 WAH, panicles from both axial and basal points of origin were nearly identical 6 WAH, and basal panicles were dominant thereafter. Results from this study indicate that when the initial stubble height is reduced from 40 to 20 cm the growth of the ratoon crop is altered by shifting panicle point of origin during the early growth period and delaying maturity.     

Use of state‐space modelling to identify ecological covariates associated with trends in pinniped demography

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Predicting use of habitat patches by spawning horseshoe crabs (Limulus polyphemus) along a complex coastline with field surveys and geospatial analyses

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Use of formulated diets as replacements for Artemia in the rearing of juvenile American lobsters (Homarus americanus)

American lobsters, Homarus americanus, have been successfully reared in hatchery operations for over a century, yet formulated diets have never been commercially produced. In recent years, commercial Artemia replacement (CAR) diets have been developed and marketed for use in aquaculture production of marine shrimp. Three separate experiments assessed the utility of rearing American lobsters on these shrimp CAR diets. First, survival and growth of stage IV American lobsters fed one of three CAR diets (Artemac 5, CAR1; Economac 4, CAR2; and Progression 3, CAR3) were compared to those of animals fed frozen adult n-3 fatty acid enriched Artemia. Survival to 3 months was highest for animals fed CAR3 (85%), while animals fed Artemia had the greatest weight gain (> 6 % day^− 1). A cost / benefit ratio analysis showed that CAR2 was the most cost efficient for juvenile production because of its low overall purchase cost. Second, stage IV lobsters were fed either CAR2 or frozen adult n-3 fatty acid enriched Artemia exclusively, or in combination (2 : 5, and 5 : 2). Again, CAR2 was a cost effective feed to use, even as a partial replacement for Artemia. Survival was higher in diets that included CAR2, and feeding it two days per week compensated for low quality Artemia. Finally, 1.5 year old lobsters fed a gelatin-bound mix of 80% CAR2 and 20% frozen Artemia for five months survived and grew equally well compared to lobsters fed gelatin-bound frozen adult Artemia, and better than a custom formulated maintenance diet. The benefits of incorporating formulated feeds into American lobster rearing programs to increase the effectiveness of enhancement programs is discussed.