Zur Prüfung vom Holzschutzmitteln gegen die marinen Holzhobrasseln der GattungLimnoria im Laboratorium

Zusammenfassung Die Durchführung von Schußmittelprüfangen gegen Holzschädlinge im Meerwasser unter Laboratoriumsbedingungen wird erörtert und eine Abänderung des von G.Becker und B.Schulze (1950) beschriebenen Verfahrens vorgeschlagen. Durch die Benußung kleinerer Versuchsgefäße und kleinerer Holzproben wird die Wahrscheinlichkeit des Befalls der Klößchen erhöht und der Material- und Arbeitsaufwand verringert. Als Versuchstier wirdLimnoria tripunctata Menzies verwendet, eine als besonders widerstandsfähig gegen Steinkohlenteeröl bekannte Bohrassel-Art.

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Summary The testing of preservatives against marine wood borers under laboratory conditions is discussed. It is proposed to alter the testing method described by G.Becker and B.Schulze in 1950. By the use of smaller test material (dishes and wood blocks) the probability of attack is increased whereas test material and work are diminished.Limnoria tripunctata Menzies, being known as an especially creosote-resistant species of the gribble, is used as test animal.

     

Kurzer Beitrag zur Biologie vonBrachycaudus amygdalinus (Schout.) (Homoptera,Aphidae) im Libanon

Summary A short note on biology of Brachycaudus amygdalinus (Schout.) (Homoptera, Aphidae) in Lebanon In the July issue of this journal (Talhouk, 1972) it was stated on page 101 that not onlyBrachycaudus helichrysi but alsoB. amygdalinus is living on almond leaves. Some new observations showedPolygonum aviculare being the summer host ofB. amygdalinus. This weed is distributed all over the country.     

Die Entomofauna der Fichtenzapfen [Picea abies (L.)Karst.] des europäischen Teiles der UdSSR

Zusammenfassung Aus den Fichtenzapfen [Picea abies (L.) Karst.] in der UdSSR wurden 91 Insektenarten gezüchtet, die sich zum Teil oder vollständig in den Zapfen entwickeln. Diese Insekten gehören zu 7 größeren Ordnungen dieser Klasse. Nach ihrer Ernährung kann man unter ihnen Phytophagen, Entomophagen, Mycophagen, Saprophagen und Koprophagen unterscheiden.Die Populationsschwankungen der Phytophagen-Schädlinge sind von den Schwankungen der Zapfenerträge abhängig. Das Vorhandensein und die Zahl der Zapfen des Baumbestandes gehören zu den Grundfaktoren der Verbreitung und der Populationsgröße der Konobionten. Einfluß der äußeren Umweltfaktoren (Besonderheiten der Waldbestände), sowie die Tätigkeit der Parasiten und Krankheitserreger beeinflussen auch die Zahl der Phytophagen, sind jedoch von zweitrangiger Bedeutung. Bei dieser Gelegenheit möchte ich meinen Dank für die Bestimmung der Insekten aussprechen: M. N.Nikolskaja, W. A.Trjapizin, M. A.Koslow, W. I.Tobias, M. I.Falkowitsch, O. K.Krishanowski, D. R.Kasparjan, G. A.Wiktorow, B. M.Mamajew (UdSSR) Herrn Dr. A.Bakke (Norwegen), Hern Dr. P.Hochmuth und Herrn Dr. S.Bouek (Tschechoslowakische Sozialistische Republik).     

Indole-3-carbaldehyde: a tyrosinase inhibitor from fungus YL185

Indole-3-carbaldehyde (1) was isolated as a tyrosinase inhibitor from the ethyl acetate-soluble fraction of extracellular fluids of unknown fungus YL185. The partial sequencing data of 18S ribosomal DNA (18S rDNA) indicate that this isolate belongs to the family Polyporaceae or Corticiaceae sensu lato. Indole-3-carbaldehyde inhibited the oxidation of l-3,4-dihydroxyphenylalanine (l-DOPA) by mushroom tyrosinase with a 50% inhibitory concentration (IC₅₀) of 1.3mM and showed inhibitory activity on melanin production in B16 melanoma cells. The aldehyde group of 1 plays an important role in eliciting tyrosinase inhibitory activity.     

Microwave pyrolysis of cellulosic materials for the production of anhydrosugars

Large-scale microwave rapid pyrolysis of cellulosic materials has been investigated. Levoglucosan (1,6-anhydro--d-glucopyranose) was obtained from a larch log as the main anhydrosugar in 2.6% yield on the basis of dry wood weight. This yield would be much higher than that obtainable by conventional pyrolysis in the largescale reaction. Levoglucosenone (1,6-anhydro-3,4-dideoxy--D-glycero-hex-3-enopyranos-2-ulose) was found to be produced in one-quarter the amount of levoglucosan. Other anhydrosugars, such as mannosan (1,6-anhydro--D-mannopyranose), galactosan (1,6-anhydro--d-galactopyranose), and xylosan (1,4-anhydro--d-xylopyranose), were also confirmed to be produced as minor components depending on the proportion of the monosaccharide content in the larch. When microwave pyrolysis of used papers and filter papers was performed, the yields of levoglucosan were about 6% and 12%, respectively, suggesting that a higher content of cellulose gives a larger amount of levoglucosan.     

Hallimasch (Armillaria mellea Vahl ex Fr.) Kumm.) als Kernfäule-Erreger an Fichte (Picea abies Karst.)

Zusammenfassung In Fichtenbest?nden (Picea abies) tritt der Hallimasch (Armillaria mellea) h?ufig als Erreger einer Kernf?ule im Stamm lebender B?ume auf. Die F?ule geht von der Basis des Wurzelstockes aus. Im Vergleich zu einer durchFomes annosus verursachten F?ule breitet sich die Hallimaschf?ule in radialer Richtung etwas langsamer, in axialer Richtung aber erheblich langsamer aus, so da? sie meist nur eine sehr geringe H?he erreicht. Die Bedingungen für das Auftreten der Hallimaschf?ule sind noch nicht bekannt.

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Summary In spruce forestsArmillaria mellea frequently is the cause of a butt rot in living stems. The decay starts in the center of the stem base. Compared toFomes annosus theArmillaria rot does grow in the radial direction slightly more slowly, but in the axial direction much more slowly. Corresponding theArmillaria rot reaches only a slight high in the stem. The conditions which promote theArmillaria rot are not yet known.

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Gef?rdert mit Hilfe von Forschungsmitteln des Landes Niedersachsen.—Dr.L. Dimitri, Dr.R. Siepmann undR. Kliefoth danke ich für ihre Mithilfe bei den Au?enarbeiten und bei den Pilzdiagnosen.     

The effects of drying on the structure and permeability of the wood of Abies grandis

Summary The effects of air-drying and solvent-drying on the sapwood of Abies grandis have been investigated by a new method for the determination of the size and number of conducting tracheid lumina and pit membrane pores which involves the measurement of gaseous permeability at various mean pressures. Both earlywood and latewood tracheids (83% of the total) were found to be conducting in solvent-dried wood, but in air-dried wood only latewood tracheids (32% of the total) were conducting. In solvent-dried wood there were on average 27,000 pit membrane pores per conducting tracheid compared with only 600 in air-dried wood. In both, the average pit membrane pore radius was about 0.1 m.Liquid permeabilities have been predicted from the calculated radii and numbers. The liquid permeability of solvent-dried wood was 31 times greater than that of air-dried wood in which the lumina were responsible for 13% of the total resistance to flow. The lumina were responsible for 39% of the resistance in solvent-dried wood and it is suggested that in first-formed earlywood the lumina may cause more than half the total resistance.A new method is described for the cleaning of direct carbon replicas of wood. In this the cellulose is removed by cellulase instead of sulphuric acid, and no wax backing is required. This provides much cleaner replicas. Electron micrographs have been obtained of both earlywood and latewood dried by the two methods.The authors wish to thank Mr. A. R. Sayers for preparing the computer programme used in this work, Dr. R. Ph. C. Johnson for his help and advice regarding the electron microscopy and Professors Matthews and Weatherley for their advice and encouragement.     

Sulfated glycofuranans as inhibitors of melanoma lung metastasis

Chemically synthesized (1 5)--d-glucofuranan, (1 5)--d-galactofuranan, (1 5)--d-xylofuranan, (1 5)--L-arabinofuranan, natural xylan, and curdlan were sulfated to investigate their inhibitory activities on B16-BL6 lung metastasis and anticoagulant activities. (1 5)--d-Glucofuranan sulfate, (1 5)--d-galactofuranan sulfate, xylan sulfate, and curdlan sulfate had binding abilities with B16-BL6 melanoma lysate. The inhibitory activities of sulfated polysaccharides on B16-BL6 lung metastasis selected by heparin binding assay were in the order (1 5)--d-galactofuranan sulfate > (1 5)---d-glucofuranan sulfate > xylan sulfate curdlan sulfate. Furthermore, (1 5)--d-galactofuranan sulfate, (1 5)--d-glucofuranan sulfate, and xylan sulfate had not only high inhibitory activity on B16-BL6 lung metastasis but also low anticoagulant activity. The correlation between chemical structure and biological activity is discussed.Part of this paper was presented at the 10th International Synposium on Wood and Pulping Chemistry, Yokohama, Japan, June 1999     

Influence of altitude on adult emergence and dynamics ofKaltenbachiola strobi (Winnertz) (Diptera: Cecidomyiidae) populations and its parasites in the Tatra National Park, Poland

A field study onKaltenbachiola strobi (Winnertz) (Diptera: Cecidomyiidae), was carried out between 1987 and 1993 in the highest mountain range in the Western Carpathians located within the Tatra National Park, in southern Poland. Rearing and analysis of 5 780 cones ofPicea abies (L.)Karst., collected from trees growing at different altitudes, yielded 30,478 individuals ofKaltenbachiola strobi, which infested 89.10% of the cones. In case of 29.81% of cones there were more than 20 larvae ofK. strobi per cone. It was shown thatK. strobi in the Tatra Mts. is more abundant in spruce stands of the upper mountain forest zone. Significant connections between the time of cone infestation byK. strobi and its parasitoids and characteristic phenophases in spruce foliage and cone development, and also the development of selected vegetation of the forest floor at different heights above sea level were determined. It was shown that the population dynamics ofK. strobi had tendency to alternate the increase and decrease in numbers every two years. It was also discovered that every two years spruce cones were inhabited by the population ofK. strobi with increased percentage of individuals having prolonged diapause. In total, the parasitoids reduced the population ofK. strobi by about 16–22.63%. Parasitism ofK. strobi in the lower mountain forest zone was higher than in the upper zone.Triplatygaster contorticornis Ratz. (Hymenoptera: Platygasteridae),Torymus azureus Boheman (Hymenoptera: Torymidae) andTetrastichus strobilanae Ratz. (Hymenoptera: Eulophidae) were most effiecient in reduction of the population ofK. strobi, and in the lower mountain forest zoneT. azureus was the dominant parasitoid species, while in the upper zoneT. contorticornis andT. strobilanae. It was shown that a considerable part of the populations ofT. azureus, T. contorticornis andT. strobilanae have their diapause prolonged and highly synchronized with the diapause of their host.     

Stiffness and wood variation of 3-year old<Emphasis Type="Italic"> Pinus radiata</Emphasis> clones

The objective of this study was to explore wood variation, especially modulus of elasticity ( moe), density, and microfibril angle ( mfa), in a three-year old Pinus radiata tree clone trial. Moreover, the study examined the potential for genetic selection of radiata pine clones with high moe using current acoustic technology. The clone selection criteria were based on growth traits, basic density, and sound velocity indices to mirror the range in wood density and moe amongst c. 1000 clones. The selected 22 clones, represented by two trees each, were measured for moe, spiral grain, wood density, compression wood percentage, and mfa. Good agreement was found between static moe and dynamic moe. Both static and dynamic moe measurements were found to be primarily dependent on mfa (clonal range 28–39 degrees). Although wood density (clonal range 300–400 kg/m³) did not have a significant influence on moe alone, it was significant in combination with mfa. Compression wood tended to reduce moe and inflate wood density. The opportunities for genetic selection of radiata clones with high stiffness seem promising as the 22 selected clones exhibited a two-fold range of static moe (2.2–4.7 GPa) and the clonal heritabilities ( ) for moe, density and mfa were high.     

Holzbiologische Untersuchungen über den Einfluß von Auftausalz auf Hamburger Straßenbäume

Zusammenfassung Aus dem Stadtgebiet von Hamburg wurden 341 Stra?enb?ume der GattungenAcer, Aesculus, Betula, Fraxinus, Platanus, Quercus, Robinia, Sorbus undTilia hinsichtlich ihrer Empfindlichkeit gegenüber Streusalz untersucht. Als Untersuchungsmethoden dienten Jahrring-analyse sowie Histometrie und energiedispersive R?ntgen-Mikroanalyse. Auf Standorten mit hohem Bodensalzgehalt zeigten die meisten B?ume seit Mitte der 60er Jahre Zuwachsrückg?nge von über 50%, was zu einer Verringerung der wasserleitenden Querschnittsfl?che in den St?mmen und vermutlich zu den Blattnekrosen in der Krone führte. Alle an streusalzbelasteten Stra?en lebenden Ahornb?ume, Linden und Ro?kastanien zeigten eine starke Vitalit?tsminderung. Lediglich die Eichen und Robinien lassen keine streusalzbedingten Wachstums?nderungen erkennen. Zur Erholung der gesch?digten B?ume sowie zur Sicherung der toleranten Baumarten müssen eine weitere Salzzufuhr verhindert und die bereits angereicherten Salzmengen aus dem Kreislauf Boden-Baum-Boden entfernt werden.

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Wood-biological investigations on the influence of deicing salt on roadside trees in Hamburg

Summary From the urban area of Hamburg, 341 roadside trees of the generaAcer, Aesculus, Betula, Fraxinus, Platanus, Quercus, Robinia, Sorbus andTilia have been investigated concerning their sensitivity to deicing salt. The methods used were tree-ring analysis, histometrical studies, and X-ray microanalysis. Since the middle of the Sixties the radial growth of most tress decreased more than 50% on all sites with a high salt content in the soil, leading to a reduction of the water-conducting area in the stems. The necrosis of the leaves is presumably a result of this situation. All maples, horsechestnuts, and limes growing along roads affected by deicing salt showed a highly decreased vitality. Only oak and black locust do not exhibit any saltinfluenced growth responses. For the recovery of the injured trees as well as for safeguarding the more tolerant tree species a further salt transport to the roots must be prevented, and the amount of salt already accumulated must be removed from the soil-tree-soil cycle.

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Wir danken Dr.H. Meyer-Spasche, Ordinariat für Bodenkunde der Universit?t Hamburg, für die Bereitstellung der bodenchemischen Standortsdaten, Prof. Dr.N. Parameswaran für die energiedispersive R?ntgen-Mikroanalyse sowie Frau Dipl.-HolzwirtS. Wrobel und FrauF. Quiehl für ihre Mithilfe bei der Laborauswertung. Die Arbeit wurde von der Beh?rde für Bezirksangelegenheiten, Naturschutz und Umweltgestaltung (BBNU) der Freien und Hansestadt Hamburg finanziell unterstützt. Die Baubeh?rde stellte Informationen über die Intensit?t der Streusalzanwendung zur Verfügung.     

A rapid method for estimating longitudinal growth stresses in logs

Summary A method of rapidly determining the longitudinal growth stress present on the surface of logs and standing trees is described. Application of the technique will enable detailed examination of stress present about the circumference and along the length of trees and logs. In addition it will enable comparisons to be made between trees, as well as monitoring changes occurring in a particular log as the result of treatment to reduce stress. Finally, its use will enable the selection of low stressed trees for genetic studies and propagation trials.The author would like to thank members of the staff of the Division, and in particular Mr. J. Barnacle, for valuable discussion relating to this work. In addition, thanks are due to Mr. K. Murray for participation in the design and construction of the equipment described.     

Inhibitory effects of <Emphasis Type="SmallCaps">l</Emphasis>-pipecolic acid from the edible mushroom, <Emphasis Type="Italic">Sarcodon aspratus</Emphasis>, on angiotensin I-converting enzyme

The aqueous extract of the edible mushroom Sarcodon aspratus showed inhibitory effects against angiotensin I-converting enzyme (ACE). l-Pipecolic acid (l-piperidine-2-carboxylic acid) was isolated from a hot-water extract in a 0.02% yield as an active principle. The mode of inhibition of l-pipecolic acid was found to be competitive, whereas its d-isomer showed no significant inhibitory effects against ACE, suggesting that the configuration of the carboxyl group in the molecule plays an important role in the enzyme inhibition.     

Structural unit of xylans from sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) and hinoki (<Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis>)

Arabinoglucuronoxylans (AGXs) isolated from the holocellulose of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa) contained one 4-O-methyl-d-glucopyranosyluronic acid (4-O-Me-d-GlcAp) residue per 6.2 d-xylopyranose (d-Xylp) residues and one 4-O-Me-d-GlcAp residue per 3.8 d-Xylp residues. These AGXs were subjected to partial acid hydrolysis. Analyses by size exclusion chromatography and electrospray-ionization mass spectroscopy of the neutral sugar fractions in the hydrolysates showed the presence of xylooligosaccharides having a degree of polymerization of 2-8 in addition to d-Xyl, suggesting that the AGXs from sugi and hinoki contained unsubstituted chains consisting of at least eight d-Xyl residues. The acidic sugars in the hydrolysates were separated into two series of aldouronic acids composed of 4-O-Me-d-GlcAp and d-Xylp by ion-exchange chromatography. The first series included aldouronic acids from aldobiouronic acid (4-O-Me-d-GlcAp-Xyl) to aldopentaouronic acids (4-O-Me-d-GlcAp-Xyl₄). The second series were aldouronic acids composed of two 4-O-Me-d-GlcAp residues and 2-4 d-Xyl residues. In these acidic sugars, the uronic acid side chains were located on two contiguous d-Xyl residues. These facts indicated that AGXs from sugi and hinoki had a structural unit containing two 4-O-Me-d-GlcAp residues on two contiguous d-Xyl residues as well as AGXs from spruce and larch.     

Wettability and the hysteresis effect in the sorption of water vapor by wood

Summary The hysteresis effect in the adsorption and desorption of water vapor by wood has been variously explained as a consequence of differences in (1) the availability of bonding sites for sorption on molecular surfaces, (2) the degree of aggregation of a swelling or shrinking cellulosic gel system, and (3) the wettability of submicroscopic capillaries within the cell wall.The wettability hysteresis of 28 tropical woods, calculated as the ratio of cosines of advancing and receding contact angles made by water, has been determined by the inclined plate method.For 13 of these species the availability of complete sorption isotherms permitted analysis by means of the Hailwood-Horrobin model to differentiate between monomolecular and polymolecular sorbed moisture. In the upper range of relative humidities, total sorption hysteresis is primarily the result of hysteresis in polymolecular sorption.Positive relationships found in this study between polymolecular sorption hysteresis and wettability hysteresis are consistent with the Kelvin equation with respect to the effect of varying contact angle and give at least partial support to Zsigmondy's explanation of hysteresis as a phenomenon of capillary condensation.Total sorption hysteresis for all 28 species in the upper range of relative humidities was also positively correlated with wettability hysteresis due to the predominant effect of polymolecular sorption hysteresis. It may be concluded that in the range of relative humidity above 60 percent, hysteresis shown by typical sigmoid isotherms is to a considerable degree a phenomenon of capillary condensation explainable by the Kelvin equation in its complete form including cosine of contact angle.

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Zusammenfassung Die Hysterese bei Adsorption und Desorption von Wasserdampf in Holz wird in der Regel als Folge von Unterschieden bei 1. der Zugänglichkeit von Bindungsstellen für die Sorption an molekulare Schichten, 2. des Aggregatzustandes eines quellenden oder schwindenden Cellulose-Gel-Systems und 3. der Benetzbarkeit der submikroskopischen Kapillaren innerhalb der Zellwand erklärt. Die Benetzbarkeits-Hysterese bei 28 tropischen Holzarten wurde durch das Verfahren mit geneigter Ebene bestimmt durch die Berechnung des Verhältnisses der cos-Werte des vorderen und hinteren Kontaktwinkels von Wasser.Bei 13 der geprüften Holzarten erlaubte das Vorhandensein der vollständigen Sorptionsisothermen eine Analyse mit Hilfe des Hailwood-Horrobin-Modells zur Unterscheidung zwischen monomolekular und polymolekular sorbierter Feuchtigkeit. In den höheren Bereichen der relativen Feuchtigkeit ist die Gesamtsorptionshysterese vorwiegend das Ergebnis der polymolekularen Sorption.Die in dieser Untersuchung gefundenen positiven Zusammenhänge zwischen der Hysterese der polymolekularen Sorption und der Benetzungshysterese stehen in Übereinstimmung mit der Kelvinschen Gleichung hinsichtlich des Einflusses des variierenden Kontaktwinkels und sie unterstützen, zumindest teilweise, die Theorie von Zsigmondy über die Hysterese als einer Erscheinung der Kapillar-Kondensation.Im oberen Bereich der relativen Feuchtigkeiten korrelierte die Gesamt-Sorptionshysterese für alle 28 Holzarten ebenfalls positiv mit der Benetzungshysterese infolge des überwiegenden Einflusses der polymolekularen Sorptionshysterese. Hieraus kann geschlossen werden, daß im Bereich der relativen Feuchtigkeit über 60% die Hysterese, die sich in einem typischen S-förmigen Verlauf der Sorptionsisothermen zeigt, zu einem wesentlichen Grade eine Erscheinung der Kapillarkondensation ist und durch die gesamte Kelvin-Gleichung, einschließlich des cos-Kontaktwinkels, erklärt werden kann.

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This research is part of a comprehensive study being conducted at the Yale School of Forestry in cooperation with the Office of Naval Research, U.S. Navy, under Contract No. 609(13), Project NR 330-001, Properties of Tropical Woods.     

Über die Wirkung vonBacillus thuringiensis var.thuringiensis-Exotoxin auf Wachsmotten-Raupen (Galleria mellonella)

Zusammenfassung Es werden die kürzlich (1966) vonVaková publizierten Befunde bestätigt und ergänzt, wonach Exotoxin vonBacillus thuringiensis var.thuringiensis aufGalleria mellonella-Raupen nach peroraler Applikation wirksam ist. Die Tatsache, daß andere Autoren bisher mit ihren Exotoxin-Präparaten keine Wirksamkeit gegenüber diesem Wirt erzielen konnten, kann verschiedene Ursachen haben. Die bisher vorliegenden Versuchsergebnisse bringen allerdings auch weiterhin noch keinen Entscheid in der Frage, obB. thuringiensis var.thuringiensis qualitativ verschiedene Exotoxine zu produzieren vermag oder nicht.

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Summary Laboratory trials withGallelia mellonella have shown that the caterpillars are susceptible to peroral application of the exotoxin ofBacillus thuringiensis var.thuringiensis. These results confirm and complete findings ofVaková (1966) which were obtained with another application technique. The fact that other authors could not find any reaction ofG. mellonella. larvae against exotoxin may be based on several reasons: The results presented here cannót decide whetherB. thuringiensis var.thuringiensis is able to produce qualitatively different exotoxines or not. Such a decision can only be made by an adequate comparison of different exotoxin-preparations on the same test-insects.

     

Über die Wirkungen der sauren Niederschläge in Waldökosystemen

Zusammenfassung Die Theorie vonB. Ulrich über Wechselwirkungen zwischen sauren Niederschl?gen und natürlicher Bodenversauerung sowie potentielle Gefahren für die W?lder werden er?rtert. Eine Literaturübersicht und pers?nliche Beobachtungen des Verfassers vor allem in Süddeutschland führen zu dem Schlu?, da? Sch?den der sauren Niederschl?ge in Waldb?den bisher nicht nachgewiesen sind. Gro?fl?chige Kompensationskalkungen zur Vorbeugung werden zum jetzigen Zeitpunkt wegen der damit verbundenen Risiken abgelehnt. Dafür empfiehlt der Verfasser, die Emission der beteiligten Schadstoffe (SO₂, NO_x) in die Atmosph?re einzuschr?nken und die Forschung über die Wirkungen saurer Niederschl?ge in W?ldern zu intensivieren. Meliorationsma?nahmen sind nur auf solchen Standorten angezeigt, wo auch herk?mmliche Entscheidungskriterien dafür sprechen.

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On the impact of acid precipitation of forest ecosystems

Summary The paper dicusses the theory ofB. Ulrich concerning the interactions of acid precipitation with natural soil acidification and the resulting potential dangers for forests. A literature review and personal oberservations made by the author mainly in southern Germany lead to the conclusion, that damaging effects of acid rain on forest soils so far are not yet documented. Liming operations on vast areas as a prophylactic measure presently are not recommended because of certain risks that are connected with this technique. Instead, the author suggests to reduce the emission of the pollutants involved (SO₂, NO_x) and to intensify basic investigations on the effects of acid rain in forests. Amelioration is only recommended for those soils, where conventional criteria support this decision.

     

Produktion von Präparaten auf der Basis von Bacillus thuringiensis var. israelensis mit UV-inaktivierten Sporen zur biologischen Bekämpfung von Mückenlarven

Zusammenfassung Zur Bekämpfung von Stechmücken-Larven geeignete Präparate vonBacillus thuringiensis var.israelensis (B. t. i. = Serotyp H₁₄) enthalten Sporen und parasporale Toxinkristalle. Um die Belastung von Oberflächenwasser mit aktiven Sporen bei einer solchen Bekämpfung möglichst gering zu halten, wurden Untersuchungen durchgeführt mit dem Ziel, die Keimzahl des Biopräparates zu reduzieren. Bei Versuchen mit einem UV-Entkeimungsgerät für Trinkwasser wurde eine 99,99%ige Inaktivierung der Sporen erzielt. Im Biotest bewirkte das bestrahlte Präparat nahezu den gleichen Effekt gegenüber Mückenlarven wie die nichtbestrahlte Suspension. Bei der Anwendung dieses neuenB. t. i.-Präparates in der kalkulierten Aufwandmenge in Oberflächenwasser wird nicht einmal die Toleranzgrenze für die Trinkwasser-Qualität überschritten. Das bedeutet, daß der Einsatz eines UV-behandeltenB. t. i.-Präparates zur Mückenbekämpfung hygienisch unbedenklich ist.

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Production of preparations based on Bacillus thuringiensis var. israelensis with UV-inactivated spores for biological control of mosquito larvae

Preparations ofBacillus thuringiensis var.israelensis (B. t. i.= serotype H₁₄) contain spores and toxic parasporal crystals. To minimize the loading of surface water with active spores in connection with mosquito control, studies were carried out to reduce the germination index of the spores using an UV equipment for sterilization of drinking water. With this method an inactivation rate of 99.99% could be obtained. In our biotest with mosquito larvae the irradiated preparation induced the same effect as the non treated one. For use ofB. t. i. in the calculated dosage in surface water the tolerance limit for drinking water will not be exceeded. Therefore, application of an UV-treatedB. t. i.-preparation for mosquito control should not be hampered by safety considerations.

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Mit 2 Abbildungen und 2 Tabellen

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Arbeitsgruppe Prof. Dr.H. W. Ludwig und Dr.W. Schnetter.     

Antihyperglycemic effects of Japanese maple Acer amoenum leaf extract and its constituent corilagin

The antihyperglycemic effects of the leaves of Acer amoenum and purification and identification of an active compound were investigated. In screening experiments for α-glucosidase inhibitory activity, methanolic extracts of A. amoenum leaves showed potent inhibitory action. This extract showed antihyperglycemic effects in sucrose-loaded mice. Fractionation of the crude extract gave the active compound corilagin [β-1-O-galloyl-3,6-(R)-hexahydroxydiphenoyl-d-glucose] by spectroscopic analysis. This is the first report about the possibility of novel utilization of the Japanese maple tree as a source of compounds for prevention or treatment of diabetes mellitus.     

Zur Frage der Wurzelentwicklung von Kiefern auf Sand und auf Pseudogley

Von allen einheimischen Baumarten liegen über die Bewurzelung der Kiefer (Pinus silvestris) die meisten Untersuchungen vor (Liese, 1926;Hilf, 1927;Vater, 1927;Laitakari, 1929;Wagenhoff, 1938). Das Interesse hierbei galt bisher besonders der Wurzelentwicklung auf Sandböden. In jüngster Zeit erfuhren die Erkenntnisse eine wesentliche Vertiefung durch Arbeiten vonEhwald (1948),Köstler (1956),Wagenknecht (1960) undKreutzer (1961). Trotzdem sind die Vorstellungen von der Bewurzelung der Kiefer auf verschiedenen Standorten, ihrer genetischen Veranlagung und ihrem Wachstum noch lückenhaft. Die folgenden Ergebnisse stammen aus Untersuchungen, die im Rahmen eines größeren Forschungsvorhabens über die Wurzeltracht der einheimischen Baumarten, an dem im Münchener Waldbauinstitut gearbeitet wird, erhoben wurden.