Pfropfmethodische Untersuchungen im Freiland für die Anlage von Samenplantagen

Ohne ZusammenfassungMit 10 TextabbildungenNach einem Vortrag, gehalten auf der Arbeitstagung für forstliche Samenplantagen vom 24.–26. Okt. 1955 in Waldsieversdorf.     

Bioavailability of hydrocarbons during microbial remediation of a sandy soil

The microbial degradation of hydrocarbons was studied in an artificially contaminated sandy soil, using a pilot-scale percolator system. After a short lag period, an intensive degradation occurred, which diminished in time and completely stopped in the end, despite large residual contaminations (residues of 56% diesel fuel, 20% n-hexadecane and 3.5% phenanthrene at the initial loadings of each 3000 mg/kg). The remaining pollutant content was influenced by the kind of hydrocarbon but was nearly independent of its initial loading. According to a model-aided analysis of the carbon dioxide production during remediation, the observed stagnation of degradation was caused by a limited bioavailability of the pollutants. The degradation in the soil-free aqueous phase was more extensive than in the soil, which suggests that the limited bioavailability in the soil can be attributed mainly to matrix-dependent rather than substrate-dependent influences. Generally, fine particles and organic matter are mainly responsible for the adsorption of pollutants to the soil matrix. Our sandy soil also bound hydrocarbons adsorptively although it contained neither silty material nor significant amounts of organic matter. As shown by Brunauer Emmett Teller (BET) analysis, the soil particles were covered by micropores, which enlarged the soil surface by a factor of 120 in comparison with the macroscopic surface area. The microporosity is the reason for the hydrocarbons being more strongly adsorbed to the sandy soil than expected. Received: 13 July 1998 / Received revision: 22 September 1998 / Accepted: 26 September 1998     

Testicular endocrine function, seasonality and semen quality of the stallion

To gain further information on gonadal function of the stallion, concentrations of testicular steroids in blood plasma (bpl) and seminal plasma (spl) and their distribution in the ejaculate were determined. Blood and semen samples from a total of 11 stallions were collected from November to July. Estrone (E1), estrone sulfate (E1S), estradiol-17beta (E2beta) and testosterone (T) were determined in bpl and spl, and in addition androstenedione (A), dehydroepiandrosterone (DHEA) and 5alpha-dihydrotestosterone (5alpha-DHT) were measured in spl. At certain points of time, aliquots of an ejaculate were centrifuged, washed and the distribution of E1, E1S, E2beta and T into seminal plasma and the sperm fraction was assessed. Hormone assay was by RIA, partly after prior separation by HPLC. Mean concentrations (X(g) x DF) were as follows: E2beta (bpl) 31.1 (1.16), (spl) 24.2 (1.42) pg ml(-1); E1 (bpl) 143.3 (1.21), (spl) 117.7 (1.53) pg ml(-1); E1S (bpl) 157.3 (1.44), (spl) 2.92 (1.42) ng ml(-1); T (bpl) 570.6 (1.43), (spl) 23.1 (1.68) pg ml(-1); A (spl) 17.9 (1.39) pg ml(-1); DHEH (spl) 12.4 (1.51) pg ml(-1); 5alpha-DHT (spl) 9.7 (1.29) pg ml(-1). Except for E2beta and A in seminal plasma, a seasonal pattern was established for all other steroids with lowest mean values occurring from November to April. From the semen parameters determined, only motility was correlated to season. There was a higher correlation among oestrogen in blp than in spl and the only correlation identified between oestrogenic and androgenic steroids was between T and E2beta in blp. In spl, T was correlated with A and 5alpha-DHT. T was the dominant free steroid in bpl while it was E1 in spl; T and E1S concentrations were about 23- and 54-fold lower in spl compared to bpl with E1S, however, showing the highest absolute values in both fluids. In the fractionated ejaculate an association of free oestrogens, particularly E2beta, with spermatozoa was observed.     

Identification of aphid species (Hemiptera: Aphididae: Aphidinae) using a rapid polymerase chain reaction restriction fragment length polymorphism method based on the cytochrome oxidase subunit I gene

Abstract  The identification of immature aphids is often difficult or impossible. This can be a problem when there is a need for a rapid and accurate diagnosis of any aphid life stage, such as for quarantine inspections and horticultural surveys. A polymerase chain reaction restriction fragment length polymorphism technique is described on the mitochondrial cytochrome oxidase subunit I (COI) gene to develop a molecular identification key for immature aphids from Victoria, Australia. The restriction enzymes HpyCH4 IV, Dra I, Hinf I, Taq I and Ssp I characterised 26 haplotypes that corresponded to 25 aphid species commonly found in southern Australian aphid surveys, including the currant-lettuce aphid Nasonovia ribis-nigri (Mosley) that has recently invaded Australia, presumably from New Zealand. Overseas specimens of Aulacorthum solani (Kaltenbach) and N. ribis-nigri showed no significant sequence difference when compared with their Australian counterparts. The COI gene provides a useful marker for diagnostic aphid surveys.     

Is there genetic structure in populations of Helicoverpa armigera from Australia?

Recent studies suggest that populations of the pest moth Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) may be genetically differentiated over short distances and time periods within Queensland, Australia. To test for genetic structure in another region of Australia, we characterized population differentiation in Victorian samples of H. armigera using eight microsatellite loci. We found no evidence of genetic structure among samples from different locations or among samples collected at different times. Moreover, Victorian samples were not differentiated from other samples of H. armigera from Queensland and New Zealand. All samples showed substantial deviations from Hardy–Weinberg equilibrium, suggesting a high frequency of null alleles typically found in microsatellites of Lepidoptera. These results indicate that populations of H. armigera are not strongly structured among regions in south‐eastern Australia.     

Determination of the triplet state energies of a series of conjugated porphyrin oligomers.

We report a systematic study of the photophysical parameters relevant to photodynamic therapy (PDT) by a new type of sensitizers, conjugated porphyrin oligomers. Due to the strong nonlinear properties of oligomers containing 2, 4 and 8 porphyrin units, these molecules are attractive candidates for PDT via multiphoton excitation. The triplet state energy levels for all molecules have been determined by the triplet quenching method, phosphorescence measurements and DFT calculations. We find that the triplet energies of all the oligomers are sufficient to generate singlet oxygen, >94 kJ mol(-1). However, low singlet oxygen quantum yields are observed for the tetramer and the octamer, as compared to the conjugated dimer and monomeric porphyrin, reflecting the decrease in triplet yield. Thus the conjugated porphyrin dimer is the most promising core structure for PDT applications via multiphoton excitation.     

Fine-scale genetic structure of grape phylloxera from the roots and leaves of Vitis

Patterns of variation at microsatellite loci suggest that root populations of the pest grape phylloxera (Daktulosphaira vitifoliae) are largely parthenogenetic in Australian vineyards. To investigate reproduction in leaf galling phylloxera and the association between these individuals and phylloxera on roots, we examined in detail genetic variation in phylloxera from a vineyard block. Some genotypes found on leaf galls within this block were not present on roots, whereas others spanned both zones. There was no evidence that genotypes on roots were the product of sexual reproduction in leaf galls. mtDNA variation was not associated with the location of the phylloxera clones. The spatial distribution of genotypes within a root population was further investigated by intensively sampling phylloxera from another vineyard block. Join-count spatial autocorrelation statistics were used to explore fine-scale spatial structure. Clones were nonrandomly distributed within the block and there was evidence that the distribution of clones followed rows. These findings suggest firstly that there is limited dispersal of root and leaf feeding phylloxera, and secondly that factors, other than vine host, are likely to be important and contribute to clonal structure within populations.