Emissions of isoprene,monoterpene and short-chained carbonyl compounds from Eucalyptus spp. in southern Australia

Eucalypts are among the highest emitters of biogenic volatile organic compounds, yet there is relatively little data available from field studies of this genus. Emissions of isoprene, monoterpenes and the short-chained carbonyls formaldehyde, acetaldehyde and acetone were determined from four species (Eucalyptus camaldulensis, Eucalyptus globulus, Eucalyptus grandis, and Eucalytpus viminalis) in Australia. A smaller comparative study was conducted on E. camaldulensis in south-eastern Australia. Carbonyl emissions, reported here for the first time from eucalypts, were generally comparable with rates reported for other species, with diurnal emissions peaking at about 4, 75 and 34 nmol m^?2 min^?1 for acetone, formaldehyde and acetaldehyde respectively. There was wide variation in diurnal isoprene and monoterpene emissions between species, but under standard conditions, isoprene emissions were much lower than previous reports. Conversely, standard emission rates of monoterpenes were as much as six times greater than previous reports for some species. Emission of each carbonyl was correlated with its ambient concentration across different species, but more weakly related to temperature. Acetaldehyde emission in particular was significantly correlated with transpiration, but not with sap flow or with ethanol concentrations in xylem sap, suggesting fermentation within the leaf and stomatal conductance are primary controlling processes. Differences in acetaldehyde exchange velocities between sites, in addition to transpiration differences, suggest stomata may indeed exert long term emission regulation, in contrast to compounds for which no biological sink exists.     

SNOW AND ICE ALBEDO MEASURED WITH TWO TYPES OF PYRANOMETERS1

ABSTRACT: In order to obtain total short-wave albedos of snow and ice, both incident and reflected solar radiation were measured over a frozen lake surface using two different types of radiation measurement devices: a Kipp and Zonen thermopile pyranometer with a spectral sensitivity of 300 to 2800 nm and a LI-COR photovoltaic pyranometer with a spectral sensitivity of 400 to 1100 am. The spectral response of the LI-COR pyranometers limits its use as a short-wave radiation measurement device. Therefore, two equations were developed to adjust both the daily incident radiation data and the daily reflected radiation data measured by the LI-COR instrument to total short-wave radiation values, i.e., to the waveband of 300 to 2800 nm (visible to near-infrared spectrum). The LI-COR data were then adjusted, and a total short-wave adjusted albedo was calculated with a modeling efficiency of 0.97.     

Dynamics of skeleton formation in the Lake Baikal sponge Lubomirskia baicalensis. Part I. Biological and biochemical studies

In ancient Lake Baikal (East Siberia), freshwater sponges have diversified to an extraordinary degree. The skeleton of Lubomirskia baicalensis, which attains a size of up to 1 m, is constructed from spicules, which are cemented into longitudinal bundles. Our X-ray analysis revealed that the architecture of the specimens follows a highly ordered radiate accretive growth pattern. The spicules have a central axial canal with an axial filament inside. This organic filament is composed of silicatein, the major enzyme involved in silica formation of the spicules. We found that the specific activity of silicatein in samples from the non-growing (basal) zone is much lower than in those from the growth zone (tips) and that even the composition of this molecule differs in these regions. The present study shows for the first time that the turnover of silicatein, the major element of the axial canal of sponge spicules, changes within a sponge specimen depending on the region in which it is found.     

Photo-Akustik-Spektroskopie an festen Stoffen

A short historic introduction into the subject and the basics of the generation of a photoacoustic signal with the emphasis upon the particularities of solid samples are given. The set-up of a two-beam photoacoustic spectrometer is described. For a better understanding of the investigations of solid samples the basic theory is presented. Specially treated subjects are: the saturation effect and how to overcome it; depth profiles of thin layers as a nondestructive method used in the investigation of a green leaf and a sheet of color reversal paper; the investigation of solid solutions in a polymer matrix with the determination of the thermic data of the matrix itself, and the fluorescence quantum yield of organic dyes solved therein. Finally a summary of numerous other applications of the PAS is given.     

The influence of chlordecone and oestrogen on the secretion of proteinaceous molecules of the mouse uterus

Ovariectomised mice were treated with sesame seed oil, oestradiol, or one of three different levels of the insecticide chlordecone (1, 1a, 3, 3a, 4, 5, 5a, 6-decachloro-octahydro-1, 3, 4-metheno-2H-cyclobuta[cd] pentalen-2-one). After 9 days of treatment, the uteri were injected with (35)S-methionine and radiolabelled proteins were flushed from uteri 4 h later. Reproductive tract weights and the total amount of radioactivity in uterine flushings were measured. Reproductive tract weights increased significantly only in animals treated with the highest dose of chlordecone tested and oestradiol-treated animals. Trichloroacetic acid (TCA) precipitated radioactivity was increased by all doses of insecticide chlordecone tested but increases were significant only at one level. The greatest stimulation of (35)S-methionine incorporation occurred in ovariectomised animals treated with oestradiol. Radioactive proteins were analysed by fluorography of two-dimensional gels. The fluorograms showed that the proteinaceous uterine secretions, as influenced by chlordecone, were greatly reduced in number as compared with those secreted under the influence of oestradiol. Chlordecone appears to cause the secretion of proteinaceous material from the uteri of mice in a qualitatively different manner than does oestradiol.