A coat protein transgene from a Scottish isolate of potato mop-top virus mediates strong resistance against Scandinavian isolates which have similar coat protein genes

Resistance tests were made on seedlings of transformed lines of Nicotiana benthamiana which contain a transgene encoding the coat protein (CP) gene of a Scottish isolate of potato mop-top virus (PMTV). This transgene has been reported to confer strong resistance to the PMTV isolate from which the transgene sequence was derived and also to a second Scottish isolate. Plants of lines of the transgenic N. benthamiana were as resistant to two Swedish and two Danish PMTV isolates as to a Scottish isolate, and of five lines tested, greater than 93.5% of transgenic plants were immune. The coat protein gene sequences of these four Scandinavian isolates were very similar to those of the two Scottish isolates. The greatest divergence between the isolates was three amino acid changes and there was less than 2% change in CP gene nucleotide sequence. It is concluded that the PMTV CP transgene used in these experiments could confer resistance against isolates from different geographical areas because it is becoming apparent that the CP genes of PMTV isolates are highly conserved.     

Changing stock of biomass carbon in a boreal forest over 93 years

The growing stock more than doubled from 1.6 to 3.4 million m³ between 1912 and 2005 in forests on an area of 387 km² in southern Finland. The stock expansion continued for 93 years noting interim results, which were available for 1959, 1982, 1994 and 1999. Forested area in the region hardly changed. Carbon sequestration was mainly a result of a long-term recovery from forest degradation, a legacy of land use in the 18th and 19th centuries. Tree demography responded to management change especially of mature stands: Average tree size and stocking density of stands increased. On average the expanding biomass stock sequestered 18 tons C annually per km² (18 g C per m²). In comparison, the emissions of fossil carbon in the region were estimated at 12 tons C per km² (12 g C per m²) on average. However, fossil CO₂ emissions exceeded biomass sequestration in recent decades. The powerful and persistent expansion of the carbon stock was an unintended co-benefit of forestry, which was motivated by the intention to improve timber yield. On the more negative side the change in management introduced clear-cuts, and a loss of diverse elements of the pre-industrial biota.     

Polymerisation of added coniferyl alcohol by inherent xylem peroxidases and its effect on fungal decay resistance of Norway spruce

It is known that active peroxidase isozymes exist in mature wood of Norway spruce (Picea abies L. Karst.) and that they remain active for years and are found even in the heartwood (in Scots pine), where all cellular activity has ceased. This peroxidase activity was utilised in the impregnation of wood blocks with a natural monolignol, coniferyl alcohol and hydrogen peroxide. The hypothesis was that the internal wood peroxidases would oxidise the added monolignol and bind it stably into the cell wall matrix, which could hinder fungal decay. Since coniferyl alcohol is not very soluble in water, the impregnation was done under vacuum with an acetone–water solution containing 10% coniferyl alcohol and 0.4 mM H₂O₂ at room temperature (ca. 0.02 g of coniferyl alcohol was added to 1 g of wood). After impregnation, dimers of coniferyl alcohol and free coniferyl alcohol were found in acetone extracts with GC–MS analysis. Penetration of coniferyl alcohol and non-extractable reaction products were studied from the wood blocks with FTIR PAS technique. The wood samples treated were also subjected to a fungal decay test with Coriolus versicolor. This treatment hindered fungal decay in a 60-day experiment and led to a dry weight loss of 8.8% in comparison with 19.9% in the control. The reactions of coniferyl alcohol and H₂O₂ in the presence of peroxidases are discussed as well as the use of monolignols to increase wood decay resistance.     

Effects of temperature and nutrient availability on plasma membrane lipid composition in Scots pine roots during growth initiation

We studied the effects of root zone temperature (RZT) and nutrient availability on free sterols and phospholipids in the plasma membrane (PM) and on PM-ATPase activity in roots of 1-year-old Scots pine (Pinus sylvestris L.) seedlings during growth initiation in the spring. Seedlings were grown for 6 weeks in hydroponic cultures with low (0.5 mM N; LN) or high (3 mM N; HN) nutrient availability. The root zone was subjected to slow warming (SW) and fast warming (FW) treatments while maintaining similar air temperatures in both treatments. Decreases in the amount of phospholipids and in the phospholipid/free sterol ratio, an increase in the degree of saturation of phospholipid fatty acids and changes in free sterol composition were observed during root growth initiation. Changes in lipid composition of the PM associated with the cold deacclimation process were detected at RZTs above 9 degrees C. Nutrient availability affected the lipid composition of the PM only when RZT was increased slowly. When RZT increased from 4 to 6 degrees C in the SW treatment, the degree of saturation of phospholipid fatty acids decreased, especially in HN seedlings. The sitosterol/stigmasterol ratio remained higher in HN seedlings than in LN seedlings. After an RZT of 9 degrees C had been reached in the SW treatment, HN caused increases in the saturation of phospholipid fatty acids and root PM-ATPase activity, and a decrease in the phospholipid/free sterol ratio. Possible effects of changes in PM lipid composition on root growth and PM-ATPase activity are discussed.     

Influence of forage harvesting regimes on dynamics of biological dinitrogen fixation of a tropical woody legume

Effects of three forage harvesting regimes-total removal of foliage and branches once (T-12) or twice a year (T-6) and 50% removal every 2 months (P-2)-on growth and biological dinitrogen fixation of Gliricidia sepium (Jacq.) Walp were studied under subhumid tropical conditions in Guadeloupe, French Antilles. Gliricidia sepium was grown in association with the perennial C(4) grass Dichantium aristatum (Poir) C.E. Hubbard in a two-storied fodder production system. The medium-term effects of pruning on N(2) fixation were assessed by the (15)N natural abundance method. Gmelina arborea Roxb. was used as the non-fixing reference. The trees in the T-12 regime followed the natural phenological cycle, and flowering and podfilling at the beginning of the dry season reduced both foliage and nodule biomass. The T-6 regime impeded flowering, and only a few flowers, on older branches, were produced in the P-2 regime. In trees in the T-12, T-6, and P-2 regimes, fixed N comprised 54-87, 54-92, and 60-87%, respectively, of the total N in aboveground biomass, depending on sampling date. Total annual accumulation of N in harvestable aboveground biomass was highest in trees in the T-6 regime at 313 kg ha(-1), of which 204 kg ha(-1) of N was fixed from the atmosphere. In all treatments, about 70% of the N exported per year from the plot in the fodder harvest came from N(2) fixation. Thus, N(2) fixation makes an important contribution to the N economy of the G. sepium-D. aristatum forage production system, and greatly reduces the need for fertilizer application.     

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.     

Effect of temperature and compression on the mechanical behavior of steam-treated wood

The mechanical behavior of steamed spruce wood changes dramatically with compression along the grain, the change being much more moderate perpendicular to the grain. The stiffness decrement due to increased temperature is greatest in the tangential material direction. The stiffness decrement due to compression is greatest along the grain. Compression to 80% compressive strain at 131°C inverts the order of the material directions regarding stiffness, the stiffness being the least along the grain. Plastic strain due to compression is greater at higher temperatures. The compression-induced decrement of stiffness along the grain is greater at higher temperatures, but the off-axis decrement of stiffness is less at higher temperatures.     

Mixing methods – assessment of potential benefits for natural resources planning

Multi-objective forest planning is a multi-methodological endeavor whose success largely depends on how well the combined use of different methods contributes to the goals of the planning. This review assessed the benefits of mixing methods in natural resources planning. A sample of 30 peer-reviewed research articles was analyzed using an evaluation framework, designed based on democracy and planning theories, and participatory planning literature, including four dimensions: transparency, flexibility, consensus building, and operability. According to analyses, mixing different types (i.e. qualitative and quantitative) of methods generally yields greater benefits than the combination of similar methods. The subsample of 12 planning cases that utilized simulation-optimization software (SOS) appeared operable and moderately transparent, whereas flexibility and consensus building were often lacking. In comparison to the wide scholarly discussion on multi-methodology and mixing methods, it was observed that successful mixing examples in natural resource planning are still scarce and there are weaknesses in bridging the methods together. There is an evident need to pursue and to better communicate the benefits of mixing. Some good mixing examples utilizing SOS provided evidence that forest planning processes would make an excellent venue for studying the benefits and caveats of using mixed methods.     

Effects of liming on chemical properties of soil, needle nutrients and growth of Scots pine transplants

The effects of limestone (2.0 and 4.0 Mg ha⁻¹) on chemical properties of soil, nutrient concentrations of needles and growth of Scots pine (Pinus sylvestris L.) transplants were investigated on three reforestation areas on infertile acidic sites in southern Finland. The limestone was applied either on the soil surface (unploughed plots) or was mixed into the topsoil (ploughed plots). All the treatments were replicated four times. Surface broadcast of lime elevated the pH in the organic layer and in the 0-10 cm layer of mineral soil. The increase in the pH of the organic layer after 21 years was, on average, 0.7 and 1.1 pH units, with a dose of lime 2 and 4 Mg ha⁻¹, respectively. On the ploughed plots, the pH in the uppermost 0-10 cm soil layer was 0.4-0.5 units higher than on the corresponding unlimed plots. Both doses of lime significantly increased the amount of exchangeable Ca and the base saturation (BS) in the topsoil on the ploughed plots, and the amount of exchangeable Ca and Mg, as well as the base saturation (BS) in the organic layer + the 0-10 cm layer of mineral soil on the unploughed plots. Regardless of the techniques used for application of lime, after 21 growing seasons the Ca and Mg concentrations in needles were significantly higher on the limed plots than on the controls. In needles, the Ca/Mn ratio was the best indicator for measuring the response to liming. Only on the unploughed plots did liming increase stand volume and dominant diameter of pines. Intensive disc ploughing produced significantly more stems and increased both stand volume and the dominant height of pines compared to unploughed plots.