Occurrence and turnover of atmospheric mercury over the nordic countries

A seasonal variation of both particle and gaseous Hg concentrations in the atmosphere is present in south-western Sweden. An average gaseous Hg level of 3.7 ng m^?3 is found in winter, compared to 2.8 ng m^?3 in summer. A weak decreasing south-north gradient for gaseous Hg in air over the Nordic countries is also present, with yearly average values from 3.2 to 2.8 ng m^?3. A gradient for particulate Hg is less clear. An air parcel trajectory sector classification of gaseous Hg levels in air, and to some extent the particulate associated Hg, clearly demonstrates the increased concentrations in the southern sectors, especially in south-western Sweden where the gaseous Hg increase is about I ng m^?3. These observations are consistent with an influence from the European continent. The average concentrations of Hg in precipitation at the various stations show a pronounced decreasing south-north gradient. A major portion of the total Hg present in precipitation is associated with particles. For the southern stations, a strong correlation between Hg and sulfate, or pH, is present suggesting a connection between Hg in precipitation and anthropogenic activities.     

Suckler cow efficiency – breed by environment interactions in commercial herds under various natural production conditions

ABSTRACT

The significance of breed by environment interaction on suckler cow efficiency traits was investigated, using production data from the Norwegian Beef Cattle Recording System and data collected (feed regimes, etc.) from 27 commercial suckler cow herds. Two statistical approaches were used; mean breed performance in extensive/intensive environments (mixed models), or as within breed regressions of cow performance on modelled cow energy intake. Aberdeen Angus produced higher weaning weight than Hereford below 12,000?MJ NE (241?kg) and Charolais below 13,000?MJ NE (244?kg) cow energy intake in the suckler period, after which the breeds re-ranked. The corresponding re-rank between Hereford and Charolais was at 14,500?MJ NE (263?kg) cow energy intake. Overall, breed by environment interactions were observed for calving interval, number/kg calves weaned/mated cow/year and energy efficiency, which emphasise that choice of cow breed should be dependent on the natural production resources available.     

Extracellular Matrix, Esterase and the Phytotoxin Prehelminthosporol in Infection of Barley Leaves by Bipolaris sorokiniana

Light microscopy and cryo-scanning electron microscopy showed that hyphae of Bipolaris sorokiniana adhered to the wax surfaces of barley leaves by means of an extensive extracellular matrix (ECM). Prehelminthosporol, the major non-host specific phytotoxin formed by B. sorokiniana was immunolocalized in large amounts in the ECM surrounding the hyphae. Similarly, esterase activity involved in degradation of the cuticular wax surface was found in the ECM. Therefore, it appears that the ECM is not only important for adhesion of the fungus to its host, but also functions as a sink of phytotoxins and lytic enzymes important for infection of the host plant.     

The Potential of High-Oil Oats under Cool Temperate Conditions

Abstract

Genetic and growth temperature effects on the oil content of oats have been studied. A line with high oil content was crossed to a line with low oil content, and the progenies from parental and F₂ plants were studied in two replicated experiments, one in the field, the other combined field/greenhouse. Interactions between greenhouse and field were found for oil content as well as for other characters. High heritability estimates and additive gene action were found for oil content. Insignificant genetic correlations were found between oil content and grain yield. F₃ families which on average had the same oil content as the highest parent were recovered. The results from two independent phytotron experiments indicate that genes conferring high oil content and low temperatures during grain filling seem to work additively towards higher oil content.