Seasonal changes in bud dormancy in relation to bud morphology, water and starch content, and abscisic acid concentration in adult trees of Betula pubescens

Annual cycles of change in bud morphology, bud burst ability, abscisic acid (ABA) concentration, and starch and water content were studied in mid-crown terminal buds of short shoots and underground basal buds of Betula pubescens Ehrh. In particular, we investigated the roles of ABA and bud water content in the regulation of bud growth. Basal buds differed morphologically from terminal buds of short shoots in that their leaf initials did not develop into embryonic foliage leaves and their total size did not increase significantly during summer. Bud burst ability, measured by forcing detached short shoots and stumps under controlled conditions, was maintained in the basal buds throughout the year, whereas the terminal buds of short shoots remained dormant until October, thereafter their bud burst ability increased gradually and reached a maximum in March-April. The ABA concentration of the basal buds was relatively constant throughout the sampling period (1-3 micro g g(DW) (-1)), whereas that of the terminal buds of short shoots, which was much higher (5-10 micro g g(DW) (-1)), showed a distinct seasonal cycle with a maximum from August to November. Bud ABA concentration decreased during the first 10 days of forcing, especially in basal buds. In both bud types, the amount of starch increased toward the autumn, declined in November, and was negligible in the terminal buds of short shoots between January and March, but in April, the amount was high again in both bud types. Water content varied characteristically in both bud types, although more distinctly in the terminal buds of short shoots, with an increase in spring before bud burst and a decrease during the summer until September. The significant morphological and physiological differences between the mid-crown terminal buds of short shoots and the underground basal buds may partly explain the characteristic growth habit of the basal buds and their development into coppice shoots after cutting the tree. The results also indicate a role for ABA in maintaining dormancy of the terminal buds of short shoots and emphasize the relationship between tissue water status and ABA concentration.     

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.     

Evaluation of the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication

OBJECTIVE: To compare the perioperative stress response in dogs administered medetomidine or acepromazine as part of the preanesthetic medication. ANIMALS: 42 client-owned dogs that underwent elective ovariohysterectomy. PROCEDURE: Each dog was randomly allocated to receive medetomidine and butorphanol tartrate (20 microgram/kg and 0.2 mg/kg, respectively, IM) or acepromazine maleate and butorphanol (0.05 and 0.2 mg/kg, respectively, IM) for preanesthetic medication. Approximately 80 minutes later, anesthesia was induced by administration of propofol and maintained by use of isoflurane in oxygen. Each dog was also given carprofen before surgery and buprenorphine after surgery. Plasma concentrations of epinephrine, norepinephrine, cortisol, and beta-endorphin were measured at various stages during the perioperative period. In addition, cardiovascular and clinical variables were monitored. RESULTS: Concentrations of epinephrine, norepinephrine, and cortisol were significantly lower for dogs administered medetomidine. Concentrations of beta-endorphin did not differ between the 2 groups. Heart rate was significantly lower and mean arterial blood pressure significantly higher in dogs administered medetomidine, compared with values for dogs administered acepromazine. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that for preanesthetic medications, medetomidine may offer some advantages over acepromazine with respect to the ability to decrease perioperative concentrations of stress-related hormones. In particular, the ability to provide stable plasma catecholamine concentrations may help to attenuate perioperative activation of the sympathetic nervous system.     

Experimental testing of rust fungus‐mediated herbivory resistance in Betula pendula

Correlative evidence suggests that pathogenic leaf rust fungus, Melampsoridium betulinum, in late summer may negatively affect folivorous insects in the following summer. Correlative association does not necessarily, however, reveal causality. Alternatively, other interconnected plant characters may determine rust densities and herbivore performance. In this study, we used birch clones and rust fungus inoculations to manipulatively test the effects of birch rust and birch genotypes on the growth performance of folivorous moth larvae of Epirrita autumnata (Lep. Geometridae) in the subsequent year. The inoculation treatment increased rust densities (three‐ to 60‐fold) compared with natural infection levels. E. autumnata performance varied among birch clones and showed 4% lower growth performance on rust‐inoculated trees. However, the larval performance did not differ between rust‐treated shoots and untreated control shoots and the use of tree‐specific rust densities as a covariant in statistical analyses failed to reveal any negative association between rust fungus and larval performance. As the slight difference in larval growth performance also levelled until pupation, we propose that rust infection has biologically insignificant importance to the performance of E. autumnata.     

CO2-defatted oats: Solubility,emulsification and foaming properties

Functional properties of conventional oat materials are relatively poor with respect to foam and emulsion formation and stabilization. This is largely due to the poor solubility of oat proteins and the presence of lipids in aqueous extracts of oats. In the experimental part of this study, extracts were prepared from different type oat flours (oat endosperm flour, oat fine flour, CO₂-defatted whole oat flour and CO₂-defatted oat flour) with a buffered aqueous extraction procedure at acidic (pH 4.5 and 6.5) and basic (pH 8.5 and 10.5) regions. The solubility of proteins was the highest at pH 10.5 and NaCl concentration of 2%. Among the extracts, CO₂-oat flour showed improved foaming and emulsifying properties at basic pH values. The presence of 0.1% NaCl resulted in the lowest foam volumes, but the emulsion activity and stability values being the highest. Sucrose addition resulted in increased foam and emulsion stability of suspensions. Heat treatment at 80 °C impaired foam properties, whereas the stability of emulsions increased with the increase in temperature from 20 °C to 80 °C. CO₂-extracted oats can be useful raw materials in beverages and other aqueous applications where protein functionality plays an important role.     

Ultrahigh-density nanowire arrays grown in self-assembled diblock copolymer templates

We show a simple, robust, chemical route to the fabrication of ultrahigh-density arrays of nanopores with high aspect ratios using the equilibrium self-assembled morphology of asymmetric diblock copolymers. The dimensions and lateral density of the array are determined by segmental interactions and the copolymer molecular weight. Through direct current electrodeposition, we fabricated vertical arrays of nanowires with densities in excess of 1.9 x 10(11) wires per square centimeter. We found markedly enhanced coercivities with ferromagnetic cobalt nanowires that point toward a route to ultrahigh-density storage media. The copolymer approach described is practical, parallel, compatible with current lithographic processes, and amenable to multilayered device fabrication.     

Kemira肥料在茶树上的应用研究

对茶树施用3种不同配比的Kemira肥料，结果表明，经过不同氮、磷、钾配比的Kemira肥料处理，土壤中有效磷，有效钾的水平和茶叶中氮、磷、钾各养分元素的含量均比仅施用氮肥的对照高，而土壤有效氮的含量低于对照，施用Kemira肥的各处理均改善了春茶某些生理生化指标，提高了茶叶的品质，同时增加了茶叶的产量和茶叶生产的经济效益。茶叶产量比对照增加5．44％～13．88％，经济产值增加3635～5717元／hm^2，增幅达到10．00％～15．72％。     

Peat Biofilters in Long-Term Experiments for Removing Odorous Sulphur Compounds

Peat was employed as a biological filter material for the removal of hydrogen sulphide (H_2> S) dimethyl sulphide (Me₂S) and methyl mercaptan (MeSH) from odorous ventilation air. Removal of H₂S was possible without the need to inoculate the filter material with oxidizing microbes whereas Me₂S required inoculation for degradation. The removal of Me₂S was decreased as a result of MeSH addition. Liming of the filter material, i.e., addition of calcium hydroxide, increased removal efficiency and activated the oxidation of H₂S without any adaptation period. As a consequence of the poor Me₂S removal efficiency of natural peat, a limed and inoculated biofilter was needed to purify mixtures of gases containing sulphur. The highest H₂S load tested with limed but otherwise natural peat was 136 g-S m^-3 day^-1, yielding a 99 % reduction. The maximum Me₂S elimination capacity with limed and inoculated peat was 175 g-S m^-3day^-1, but removal became unstable when the load exceeded 150 g-S m^-3day^-1. The maximum MeSH load tested was 107 g-S m^-3day^-1, yielding 98 % removal.