Foliar and yield response of Santa rosa plum to saline water spray

Summary Canopies of 22-year-old Santa Rosa plum trees irrigated with mini-sprinklers below the canopy with nonsaline (0.3 dS/m) water were sprayed weekly during one irrigation season with water having six levels of salinity (0.3, 1.1, 2.1, 3.3, 4.5, and 6.8 dS/m) to evaluate the extent of leaf injury, foliar absorption of Cl and Na, and yield response. Recognizable leaf injury was caused by spray water containing 29 mol/m³ of chloride and 15 mol/m³ of sodium. Severe leaf damage occurred when the leaf chloride and sodium concentrations exceeded 300 and 125 mmol/kg (dry weight), respectively. These concentrations were higher than those causing foliar damage on other trees in the same orchard which had been irrigated below the canopy with water having the same salinity as that sprayed on the canopy. No residual foliar injury was observed during the irrigation season following the year when the spray treatments were applied. Fruit yield measured six weeks after treatments were initiated was unaffected. In the following 2 years, yield was reduced by the highest salinity levels, even though the salt spray treatments were not continued and no foliar injury was visible.     

Cat scratch disease: U.S. clinicians' experience and knowledge

Cat scratch disease (CSD) is a zoonotic infection caused primarily by the bacterium Bartonella henselae. An estimated 12,000 outpatients and 500 inpatients are diagnosed with CSD annually, yet little is known regarding clinician experience with and treatment of CSD in the United States. Questions assessing clinical burden, treatment and prevention of CSD were posed to 3,011 primary care providers (family practitioners, internists, paediatricians and nurse practitioners) during 2014–2015 as part of the annual nationwide DocStyles survey. Among the clinicians surveyed, 37.2% indicated that they had diagnosed at least one patient with CSD in the prior year. Clinicians in the Pacific and Southern regions were more likely to have diagnosed CSD, as were clinicians who saw paediatric patients, regardless of specialty. When presented with a question regarding treatment of uncomplicated CSD, only 12.5% of clinicians chose the recommended treatment option of analgesics and monitoring, while 71.4% selected antibiotics and 13.4% selected lymph node aspiration. In a scenario concerning CSD prevention in immunosuppressed patients, 80.6% of clinicians chose some form of precaution, but less than one‐third chose the recommended option of counseling patients to treat their cats for fleas and avoid rough play with their cats. Results from this study indicate that a substantial proportion of U.S. clinicians have diagnosed CSD within the past year. Although published guidelines exist for treatment and prevention of CSD, these findings suggest that knowledge gaps remain. Therefore, targeted educational efforts about CSD may benefit primary care providers.     

Superfast muscles set maximum call rate in echolocating bats

As an echolocating bat closes in on a flying insect, it increases call emission to rates beyond 160 calls per second. This high call rate phase, dubbed the terminal buzz, has proven enigmatic because it is unknown how bats are able to produce calls so quickly. We found that previously unknown and highly specialized superfast muscles power rapid call rates in the terminal buzz. Additionally, we show that laryngeal motor performance, not overlap between call production and the arrival of echoes at the bat's ears, limits maximum call rate. Superfast muscles are rare in vertebrates and always associated with extraordinary motor demands on acoustic communication. We propose that the advantages of rapid auditory updates on prey movement selected for superfast laryngeal muscle in echolocating bats.     

Improving seedbed conditions using a winged sowing point for direct drilling of wheat

Suitability of a winged point for sowing to improve early growth of wheat crops using direct drilling on a hardsetting soil in Cowra, New South Wales, Australia was evaluated. Soil physical conditions, including bulk density, shear strength, water content, water potential and porosity close to the seedlings, were monitored. Comparisons were made between the winged point and the conventional combine point.Results indicate that on a compacted soil (bulk density = 1.7 Mg m⁻³), use of the winged point encouraged downward growth of roots. Sowing with the winged point doubled the root length density in the 25–50 mm layer below seed level compared with that of the combine point 18 days after sowing. Bulk density and shear strength measurements did not explain this difference. However, analysis of epoxy-resin-impregnated seedbeds revealed the presence of more large voids (> 4 m) at 50- and 75-mm depths in the plots sown with the winged points. These large voids were in the form of fracture planes possibly created by the wing. Sowing with a combine point caused compaction, especially on a previously loosened soil (bulk density = 1.4 Mg m⁻³), and this was found to restrict downward growth of roots.     

Identification and characterization of serum complement activity in the American crocodile (Crocodylus acutus)

Incubation of unsensitized sheep red blood cells with serum from the American crocodile (Crocodylus acutus) resulted in a concentration-dependent hemolysis. The hemolytic activity was heat-sensitive, and inhibited by EDTA in a concentration-dependent manner. The EDTA-inhibited SRBC hemolysis could be restored by the addition of excess Ca²⁺ or Mg²⁺, but not Ba²⁺ or Cu²⁺, revealing the specificity of this activity for these two divalent cations. The hemolytic activity of crocodile serum was titer-dependent, with 329 μL producing 50% of maximal SRBC hemolysis. The complement activity was also temperature-dependent, with decreased activity at lower temperatures (5–15 °C) and maximal activity occurred at 30–40 °C. The hemolysis occurred relatively slowly, with near zero activity after 10 min, 40% of activity observed within 15 min of exposure to SRBCs, and maximal activity at 30 min.     

Spatial variation and understorey competition effect of Pinus radiata fine roots in a silvopastoral system in New Zealand

In designing agroforestry systems, the combination of tree genotype (orspecies) and pasture species and the spatial arrangement of trees are importantconsiderations. The spatial variation of fine root length density (FRLD) ofthree radiata pine (Pinus radiata D. Don) genotypes,referred to here as clone 3, clone 4 and seedlings, was studied in athree-year-old temperate silvopastoral experiment. The genotypes were plantedwith three understorey types: ryegrass (Lolium perenne)mixed with clovers (Trifolium spp), lucerne(Medicago sativa), and control (bare ground). Also fineroot distribution of both tree and pasture species with soil depth and inrelation to tree row (0.9 m north or south of and within the rippedtree row) was studied. Greater FRLD was found in clonal than in seedling treesin the bare ground treatment but not in the two pasture treatments, and in the0–0.1 m but not in the 0.1–0.2 or 0.2–0.3m soil layers. Clonal trees had a greater ability to develop a moreextensive root system, especially in the 0–0.1 m soil layer,but that advantage disappeared when they were planted with pasture species sincecompetition from the pasture species was most severe in the 0–10cm layer. The FRLD of lucerne was greater than that ofryegrass/clovers, consistent with the greater aboveground biomass production oflucerne. Pasture species FRLD was greater on the south (wetter) than on thenorth side of the ripline or in the ripline. The interception of prevailingsoutherly rain-bearing wind by tree crowns resulted in the south side beingwetter than the north side. Results indicated that production and distributionof fine roots of both tree and pasture species responded to changes in themicroclimate. We suggest that to optimize pasture/tree biomass productionplanting trees in the north-south direction is better than in the east-westdirection at the studied site. This revised version was published online in June 2006 with corrections to the Cover Date.