Wood properties of Scots pines (Pinus sylvestris) grown at elevated temperature and carbon dioxide concentration

Impacts of elevated temperature and carbon dioxide concentration ([CO2]) on wood properties of 15-year-old Scots pines (Pinus sylvestris L.) grown under conditions of low nitrogen supply were investigated in open-top chambers. The treatments consisted of (i) ambient temperature and ambient [CO2] (AT+AC), (ii) ambient temperature and elevated [CO2] (AT+EC), (iii) elevated temperature and ambient [CO2] (ET+AC) and (iv) elevated temperature and elevated [CO2] (ET+EC). Wood properties analyzed for the years 1992-1994 included ring width, early- and latewood width and their proportions, intra-ring wood density (minimum, maximum and mean, as well as early- and latewood densities), mean fiber length and chemical composition of the wood (cellulose, hemicellulose, lignin and acetone extractive concentration). Absolute radial growth over the 3-year period was 54% greater in AT+EC trees and 30 and 25% greater in ET+AC and ET+EC trees, respectively, than in AT+AC trees. Neither elevated temperature nor elevated [CO2] had a statistically significant effect on ring width, early- and latewood widths or their proportions. Both latewood density and maximum intra-ring density were increased by elevated [CO2], whereas fiber length was increased by elevated temperature. Hemicellulose concentration decreased and lignin concentration increased significantly in response to elevated temperature. There were no statistically significant interaction effects of elevated temperature and elevated [CO2] on the wood properties, except on earlywood density.     

The role of competitors for <Emphasis Type="Italic">Chrysomela lapponica</Emphasis>, a north Eurasian willow pest,in pioneering a new host plant

The Palaearctic leaf beetle Chrysomela lapponica usually feeds upon willows in the northern region of its occurrence. However, in Central Europe, some populations are known that have specialised on birch. In this study, we investigated the significance of other herbivores occurring together on the same host plants as possible exploitative competitors of C. lapponica. Two populations were studied: a population from Finland specialised on the willow Salix borealis, and a population from the Czech Republic, specialised on the birch Betula pubescens. Abundances of folivorous and suctivorous insects on both host plants were recorded at both population sites. The willow leaf beetle Phratora vitellinae was the most abundant herbivorous insect at both study sites on willow. A field study was conducted to examine the effects of P. vitellinae on the performance of C. lapponica. The presence of P. vitellinae larvae on the same twig upon which C. lapponica larvae were feeding did not affect increase of body weight in C. lapponica larvae. Thus, the high resource availability of both willows and birches suggest that interspecific competition is unlikely to be a selection factor driving the evolution of host shift in C. lapponica.     

Crystallinity of wood and the size of cellulose crystallites in Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis>)

X-ray diffraction was used to study variations in the crystallinity of wood and the average thickness and length of the crystallites of cellulose as a function of the number of the year ring in Norway spruce [Picea abies (L.) Karst.]. The crystallinity increased from ring 4 to ring 10 from the pith and was constant after ring 10. The crystallinity of mature wood was about 30% ± 5%. The average thickness and average length of the crystallites were 3.2 ± 0.1nm and 28 ± 2nm, respectively; and no systematic variation of these values with the number of the year ring was observed. The mean microfibril angle decreased near the pith but was constant in the mature wood.     

Diameter growth of Scots pine (Pinus sylvestris) trees grown at elevated temperature and carbon dioxide concentration under boreal conditions

We investigated the impacts of elevated temperature and carbon dioxide concentration ([CO2]) on diameter growth of Scots pine (Pinus sylvestris L.), aged about 20 years, grown with a low nitrogen supply in closed chambers at (i) ambient temperature and [CO2] (AT+AC), (ii) ambient temperature and elevated [CO2] (AT+EC), (iii) elevated temperature and ambient [CO2] (ET+AC), and (iv). elevated temperature and [CO2] (ET+EC). Each treatment was replicated four times. Diameter growth was monitored with a band dendrograph at 15-min intervals throughout the growing seasons of 1997, 1998 and 1999. Over the monitoring period, diameter growth began 2-3 weeks earlier in trees in the ET+EC and ET+AC chambers than in trees in the AT+AC and AT+EC chambers. However, the cessation of growth occurred about a week later in trees in the ET+EC, ET+AC and AT+EC chambers compared with the AT+AC chambers. The duration of the growing season was 115 and 108 days in the ET+EC and ET+AC chambers, respectively, and 95 and 84 days in the AT+EC and AT+AC chambers, respectively. The ET+AC and ET+EC treatments enhanced diameter growth most early in the growing season, whereas in trees in the AT+AC and AT+EC treatments diameter growth rate was highest in the middle of the growing season. Diameter growth rate leveled off more slowly in trees in the ET+EC and AT+EC treatments than in the other treatments. The growth response to elevated T, elevated [CO2] or both decreased with time and it was less than the maximum observed in other studies for small seedlings and under optimal growth conditions. Nevertheless, cumulative diameter growth for the 3-year period was 67% greater in trees in the ET+EC treatment, and 57 and 26% greater in trees in the AT+EC and ET+AC treatments, respectively, compared with trees in the AT+AC treatment. Over the 3 years, [CO2] had a statistically significant (P < 0.10) effect on both absolute and relative diameter growth, but the interaction between [CO2] and temperature was not significant.     

Identification of somatic hybrids of dihaploid Solanum tuberosum lines and S. brevidens by species specific RAPD patterns and assessment of disease resistance of the hybrids

Summary Symmetric somatic hybrids were produced by electrofusion of protoplasts of two dihaploid tuber-bearing potato (Solanum tuberosum L.) lines and Solanum brevidens Phil., a diploid non-tuber-bearing wild potato species. A total of 985 plants was obtained. Verification of nuclear hybridity of putative hybrids was based on additive RAPD patterns, general morphological characteristics and chromosome counts. 53 (90%) calli regenerated into plants which were identified as somatic hybrids. Most of the hybrids were aneuploids at the tetraploid (4×) or hexaploid (6×) level. The 20 hybrids tested expressed a high level of resistance to potato virus Y (PVY ^N ) characteristic of the S. brevidens parent. Resistance to late blight (Phytophthora infestans (Mont.) de Bary) varied between hybrids, but was on average better than that of the fusion parents. Resistance of hybrids to bacterial stem rot (Erwinia carotovora subsp. atroseptica (van Hall) Dye) was not superior to that of commercial potato cultivars.     

Effect of glucose in removal of microcystin-LR by viable commercial probiotic strains and strains isolated from dadih fermented milk

The removal of the cyanobacterial peptide toxin microcystin-LR at 4 and 37 degrees C by six commercial probiotic strains and Lactobacillus plantarum strains IS-10506 and IS-20506 isolated from dadih, Indonesian traditional fermented milk, was assessed in this study. The aim was to evaluate the main factors influencing the viability and metabolic activity of the probiotic strains, as well as their capacity to remove microcystin-LR. Both L. plantarum strains isolated from dadih, as well as Bifidobacterium lactis strains Bb12 and 420, were shown to be more resistant, and >85% remained viable in phosphate-buffered saline (PBS) solution for 48 h of incubation at either temperature, while the viability of the other four commercial bacteria decreased markedly over time. The effect of glucose on viability and removal of toxin was shown to be a strain-specific and strain-dependent property, but in general, the efficiency of microcystin-LR removal increased when glucose was added to the solution. A maximum removal of 95% was observed for L. plantarum strain IS-20506 (37 degrees C, 10 (11) colony-forming units mL(-1)) with 1-2% glucose supplementation and 75% in PBS alone.     

Impacts of the Management of Radioactively Contaminated Land on Soil and Phosphorus Losses in Finland and Scotland

Although radioactive contamination of agricultural land mayrequire food production to cease, in many situations food contamination can be kept below the intervention limits throughapplication of countermeasures. However, the radiological benefits of these measures may be accompanied by negative impacts on the environment. The aim of this work was to assessthe impacts of selected countermeasures on water quality via losses of soil and phosphorus in river catchments in Scotland and Finland. Four countermeasures, suitable for different levelsof radioactive deposition, were studied: deep ploughing, skim and burial ploughing, changes in the feeding of livestock andcessation of production. The assessments were performed using adeterministic mathematical simulation model capable of estimatingthe impact of changes in management practices and land use on thehydrology and on soil and phosphorus losses from land to water.Skim and burial ploughing had the least impacts. Deep ploughinggenerally reduced phosphorus losses but had variable effects on soil loss, which depended on the erodibility of the subsoil. Changes in the dairy feeding regime from roughage-dominated (local grass production) to more concentrates (local cereal production or imported) had variable impacts, depending on the local agricultural systems and management practices. The worstimpacts on erosion and phosphorus losses may occur where large areas of grassland are converted to cereal production. Cessationof agricultural production resulted in large (50–90%) reductions in soil and phosphorus losses. The most recommended ofthe assessed countermeasures is skim and burial ploughing, but its wider use depends on the availability of specialized technical equipment.     

A comment on the membrane filter technique for estimation of length of fungal hyphae in soil

A simple direct method is described to measure the length of fungal hyphae in soil. The accuracy of the method is discussed and comparison is made with other methods recommended for assaying fungal biomass in soil. Some results showing the seasonal fluctuation of mycelial length in soil are presented.     

Detection of a red supergiant progenitor star of a type II-plateau supernova

We present the discovery of a red supergiant star that exploded as supernova 2003gd in the nearby spiral galaxy M74. The Hubble Space Telescope (HST) and the Gemini Telescope imaged this galaxy 6 to 9 months before the supernova explosion, and subsequent HST images confirm the positional coincidence of the supernova with a single resolved star that is a red supergiant of 8(+4)(-2) solar masses. This confirms both stellar evolution models and supernova theories predicting that cool red supergiants are the immediate progenitor stars of type II-plateau supernovae.     

Pathogenic,Enterotoxin-Producing Staphylococci in Mink Feed and Mink Feed Raw Materials

Samples of 51 mink feeds and 101 raw material batches were analysed for pathogenic staphylococci. Of the feed samples 37 % were contaminated with pathogenic staphylococci, the mean count being 3.02 log CFU (colony forming units)/g and the highest count being 4.48 log CFU/g of feed. Of the raw materials investigated, slaughter-house offals were most frequently contaminated and contained highest counts of S. aureus, 60 % of the samples being positive with a mean log count of 3.86/g and a maximum of 5.70/g. Forty-eight staphylococcal isolates were tested for eniterotoxin production. Toxin A, B or G were produced by eight isolates, A being the most common. None of the isolates produced B or E toxins.