Measuring compression wood severity in spruce

As the severity of compression wood influences the mechanical and chemical properties of wood it is desirable to be able to measure compression wood severity. However, so far no satisfactory method has been reported in the literature. Here we describe how scanning FTIR micro-spectroscopy can be employed to achieve CW severity measurements on increment cores of Norway spruce (Picea abies (L. Karst.) and Sitka spruce (Picea sitchensis (Bong.) Carrière). Radial wood strips were converted into sawdust by a process that maintained their spatial orientation. Samples prepared in this way were scanned with an FTIR-microscope in reflective mode and from the spectra obtained a CW-indicator was calculated representing aromatic and carboxyl signals. This FTIR CW-indicator correlated well with alternative CW identification techniques (namely microfibril angle, transmitted light and immunolabelling of beta 1–4 galactan), which have been used to validate the method. Repeatability of the measurements was good and no systematic difference between spruce species was found. The achievable resolution of the measurements was of sub-mm order. The CW indicator described offers the opportunity to correlate CW severity with mechanical wood properties in spruce.     

Traditional seed management and genetic diversity in barley varieties in high-hill agro-ecosystems of Nepal

Chawali and Lekali are two common farmer’s barley varieties or landraces in Jumla, Nepal (2,240–3,000 m) with small to bold grains and wide adaptation from irrigated low lands to high hills. This study was undertaken to test whether features of the traditional seed system can significantly influence the diversity of a crop and its conservation on-farm. In Jumla (high-hill), the barley seed system is completely informal and is mainly from farmer to farmer. In the present study, the seed flows and the pattern of genetic diversity in barley were investigated to detect differences between the two varieties and test the divergence among populations of each variety These data suggested that Chawali, the more common variety, was less subject to homogenising gene flow between farms than was Lekali. A total of 128 farming households were surveyed for seed supply information and 128 populations for each landrace from two villages: Kartikswami and Talium were collected for SSR diversity analysis. Some 92 SSRs were screened in an initial sample of 20 barley populations of both landraces and 2 improved varieties (LG-51 and Soluwa). Of the 81 SSRs that consistently amplified, only 15 SSRs (19%) were polymorphic with gene diversity values ranging from 0.09 to 0.71. A medium to low diversity was detected among the landrace populations of barley varieties. Chawali populations were less polymorphic within ecological groups, and more divergent between than were Lekail populations. This result accords with Chawali having a more conservative local seed system.     

Wound healing in potato tuber tissue. 2. Varietal and anatomical variation

Summary The wound healing potential of 15 UK maincrop potato cultivars was assessed from the ability of discs of cortical and medullary tissue to become resistant to the loss of water vapour, as their surfaces suberized. Varietal rankings were moderately consistent over four experiments in two years, with cvs Désirée, Bintje and Pentland Hawk showing rapid healing and Majestic, Redskin and Pentland Crown rather slow healing. Wound healing rates in cortical and medullary tissue were generally similar. Since fast wound healing is not the dominant mechanism of resistance to disease, correlations with established ratings for resistance to individual diseases were not found, but some protection against a broad spectrum of storage diseases is likely. Wound healing rankings correlated with varietal resistance to mechanical damage.

---

Zusammenfassung Die Versuche sollten sortenbedingte Unterschiede bei Wundheilungs-Raten demonstrieren. Ausserdem galt es herauszufinden ob sich Unterschiede im Wundheilungs-Potential zwischen Rinden- und Markgewebe ergeben, wodurch sich die relative Bedeutung von flachen gegenüber tiefen Wunden darstellen würde. Der Anstieg in der internen Widerstandsf?higkeit im Hinblick auf Verlust von Wasser-Dampfdruck von Scheiben von Knollengewebe, ein Mass für die Suberinisierung an Wundoberfl?chen, wurde über 6–9 Tage in vier Versuchen über zwei Lagerperioden verfolgt. Die 15 untersuchten sp?ten Kartoffelsorten zeigten betr?chtliche sortenbedingte Abweichungen in allen vier Experimenten (Tabellen 1 und 2). Zwischen den beiden Perioden waren die Schwankungen nur gering, ebenso zwischen den Untersuchungen im Herbst und im Frühjahr (Tabelle 3). Die H?he des Wasserverlustes bei Rinden- und Markgewebe waren im wesentlichen gleich (Tabelle 2) und korrelierten zwischen den Sorten (r=0,84,P<0,001). In den ersten 4–5 Tagen der Inkubation entwickelte sich die interne Widerstandsf?higkeit gegen Wasserverlust z?gernd, bei ungef?hr 6 Tagen dann schneller (Abb. 1). Sowohl das Ausmass des schnelleren Anstiegs als auch die Zeit des Beginns bestimmten den generellen Grad an Resistenz gegen Wasserverlust über die gesamte Inkubationsperiode (Abb. 1). Sorten mit rapider Wundverheilung in diesen Untersuchungen, z.B. Désirée und Bintje, befanden sich unter denjenigen, welche von Blight & Hamilton (1974) mit geringer Anf?lligkeit gegen mechanische Besch?digung eingestuft worden waren.

---

Résumé Le but de cette étude est de mettre en évidence l'importance des variations dans le taux de cicatrisation des blessures selon les variétés et de rechercher s'il existe une différence dans le potentiel de cicatrisation entre les tissus corticaux et médullaires qui pourraient déterminer l'importance relative des blessures légères et profondes. L'augmentation de la résistance interne à la perte en vapeur d'eau à partir de lamelles de tissus de tubercules, comme mesure de subérisation des surfaces blessées, a été suivie pendant 6 à 9 jours dans 4 expérimentations au cours de deux campagnes de conservation. Les 15 principales variétés testées ont montré un degré variétal important dans les 4 essais (tableau 1 et 2). Le classement des variétés n'a guère varié d'une année à l'autre et entre automne et printemps (tableau 3). Les taux de perte en eau des tissus médullaire et cortical sont en général équivalents (tableau 2) et correlés avec les variétés (r=0,84,P<0,001). La résistance interne à la perte en eau évolue lentement les 4–5 premiers jours d'incubation, et plus rapidement après 6 jours environ (fig. 1). La variation dans la phase rapide, et dans sa date de démarrage détermine le niveau global de résistance à la perte en eau pour toute la période d'incubation (fig. 1). Les variétés qui montrent une évolution rapide de cicatrisation dans cette étude, telles que Désirée et Bintje, sont parmi celles estimées par Blight & Hamilton (1974), qui présentent une faible sensibilité à l'endommagement mécanique.

     

Riverine Flux of Metals from Historically Mined Orefields in England and Wales

Water, Air, &; Soil Pollution - The flux of metals at the tidal limits of major rivers are an important metric of freshwater contaminant transfer to marine habitats, reported in Northeast...     

Drying and wetting of Mediterranean soils stimulates decomposition and carbon dioxide emission: the "Birch effect"

Observations on the net carbon exchange of forests in the European Mediterranean region, measured recently by the eddy covariance method, have revived interest in a phenomenon first characterized on agricultural and forest soils in East Africa in the 1950s and 1960s by H. F. Birch and now often referred to as the "Birch effect." When soils become dry during summer because of lack of rain, as is common in regions with Mediterranean climate, or are dried in the laboratory in controlled conditions, and are then rewetted by precipitation or irrigation, there is a burst of decomposition, mineralization and release of inorganic nitrogen and CO(2). In forests in Mediterranean climates in southern Europe, this effect has been observed with eddy covariance techniques and soil respiration chambers at the stand and small plot scales, respectively. Following the early work of Birch, laboratory incubations of soils at controlled temperatures and water contents have been used to characterize CO(2) release following the rewetting of dry soils. A simple empirical model based on laboratory incubations demonstrates that the amount of carbon mineralized over one year can be predicted from soil temperature and precipitation regime, provided that carbon lost as CO(2) is taken into account. We show that the amount of carbon returned to the atmosphere following soil rewetting can reduce significantly the annual net carbon gain by Mediterranean forests.     

Species differentiation of Leptospira interrogans serovar hardjo strain Hardjobovis from strain Hardjoprajitno by DNA slot blot hybridisation

Slot blot hybridisation studies with total genomic DNA probes were used to compare Leptospira interrogans serovar hardjo strain Hardjoprajitno, strain Hardjobovis and a number of other Leptospira interrogans serovars. Strains Hardjoprajitno and Hardjobovis were found to have little genetic relationship with each other when compared to some of the other serovars tested. Hardjoprajitno is closely related to serovar icterohaemorrhagiae and not to Hardjobovis whereas Hardjobovis is closely related to serovars vietnam, balcanica and javanica but not to serovar icterohaemorrhagiae; this places strain Hardjoprajitno in the species L interrogans and strain Hardjobovis in the species L borgpetersoni. Because of this lack of genetic relatedness between strains Hardjoprajitno and Hardjobovis, it is proposed to remove the prefix Hardjo from the strain name Hardjobovis and call it L borgpetersoni serovar hardjo strain Bovis.     

Epidemiological study of pasture-associated laminitis and concurrent risk factors in the South of England

A retrospective study of laminitis was carried out to identify risk factors associated with this disease on an East Anglian farm with approximately 1000 animals living in an area of 1000 acres. Medical records between January 1997 and May 2000 and between April 2005 and March 2008 were reviewed, and the age, sex, weight (kg), height (inches [in] and hands [H]) and weight-to-height ratio (kg/in) was recorded. The prevalence, incidence and seasonality of laminitis were determined and their relationship to the monthly temperature, rainfall and hours of sunshine was evaluated. Averaged over the six years, the highest prevalence (2.6 per cent) and incidence (16 cases/1000 animals) of laminitis occurred in May. The findings of a multivariate analysis revealed that females (P=0.007, odds ratio [OR] 1.46, 95 per cent confidence interval [CI] 1.1053 to 1.9646) and light animals (P ≤ 0.001, OR=0.995, 95 per cent CI =0.9932 to 0.9963) had the greatest risk of developing laminitis. A positive association was found between hours of sunshine and incidence (P=0.007, relative risk [RR] 1.009, 95 per cent CI 1.001 to 1.012) and prevalence (P=0.002, RR 1.008, 95 per cent CI 1.003 to 1.012) of laminitis. The data suggest that there is a relationship between season, sex of the animal and the development of laminitis.     

A review of non-equilibrium water flow and solute transport in soil macropores: principles, controlling factors and consequences for water quality

This review discusses the causes and consequences of ‘non‐equilibrium’ water flow and solute transport in large structural pores or macropores (root and earthworm channels, fissures and interaggregate voids). The experimental evidence suggests that pores larger than c. 0.3 mm in equivalent cylindrical diameter allow rapid non‐equilibrium flow. Apart from their large size and continuity, this is also due to the presence of impermeable linings and coatings that restrict lateral mass exchange. Macropores also represent microsites in soil that are more biologically active, and often more chemically reactive than the bulk soil. However, sorption retardation during transport through such pores is weaker than in the bulk soil, due to their small surface areas and significant kinetic effects, especially in larger macropores. The potential for non‐equilibrium water flow and solute transport at any site depends on the nature of the macropore network, which is determined by the factors of structure formation and degradation, including the abundance and activity of soil biota such as earthworms, soil properties (e.g. clay content), site factors (e.g. slope position, drying intensity, vegetation) and management (e.g. cropping, tillage, traffic). A conceptual model is proposed that summarizes these effects of site factors on the inherent potential for non‐equilibrium water flow and solute transport in macropores. Initial and boundary conditions determine the extent to which this potential is realized. High rain intensities clearly increase the strength of non‐equilibrium flow in macropores, but the effects of initial water content seem complex, due to the confounding effects of soil shrinkage and water repellency. The impacts of macropore flow on water quality are most significant for relatively immobile solutes that are foreign to the soil and whose effects on ecosystem and human health are pronounced even at small leached fractions (e.g. pesticides). The review concludes with a discussion of topics where process understanding is still lacking, and also suggests some potential applications of the considerable knowledge that has accumulated in recent decades.     

Long-term effects of elevated carbon dioxide concentration and provenance on four clones of Sitka spruce (Picea sitchensis). I. Plant growth, allocation and ontogeny

Four clones of Sitka spruce (Picea sitchensis (Bong.) Carr.) from two provenances, at 53.2 degrees N (Skidegate a and Skidegate b) and at 41.3 degrees N (North Bend a and North Bend b), were grown near Edinburgh (55.5 degrees N), U.K., for three growing seasons in ambient (~350 micromol per mol) and elevated (~700 micromol per mol) CO2 concentrations under conditions of non-limiting water and nutrient supply. Bud phenology was not affected by elevated [CO2] in the second growing season, but in the third year, the duration of shoot extension growth in three of the four clones (North Bend clones and Skidegate a) was significantly shortened, because of the suppression of lammas growth. Saplings in elevated [CO2] had significantly greater dry masses of all components than saplings in ambient [CO2]. However, comparison of relative component dry masses between plants of similar size showed no effect of [CO2] treatment on plant allometric relationships. This finding, and the observed suppression of lammas growth by high [CO2] during the third growing season suggests that the main effect of increasing [CO2] is to accelerate sapling development. Clonal provenance did not affect dry mass production in ambient [CO2]. However, in elevated [CO2] the more southerly clones significantly out-performed the more northerly clones when grown at a latitude close to the latitudinal provenance of the Skidegate clones. As atmospheric carbon dioxide concentration rises, such changes in the relative performance of genotypes may be exploited for economic gain through appropriate selection of provenances for forest plantings.