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1.
Summary The pressure membrane and pressure plate techniques were used to establish the moisture content-water potential (M-) relationship of red pine (Pinus resinosa Ait.) sapwood in desorption above the fiber saturation point. The moisture content-water potential relationship is required for the development of a model of drying considering the gradient of water potential as the driving force of moisture in wood. This relationship was established at 18, 56 and 85 °C for radial desorption. The results obtained demonstrate that water potential increases with temperature T at a given moisture content M. There is no significant variation of /T with temperature. Also, there is no plateau at intermediate moisture contents as was the case for the M- relationship of aspen sapwood established in a previous work. The effective integral and differential pore size distributions inferred from the M- relationship are also presented. The largest proportion of effective pore openings was found for a radius of 0.2 m. This value can be related to the pit membrane openings of red pine.This research project is currently supported by the Natural Sciences and Engineering Research Council of Canada under grant no. OGP0121954  相似文献   

2.
Zusammenfassung Aphelenchoides ritzemabosi wurde erstmals auch anFicus elastica undRodgersia aesculiformis nachgewiesen. Schäden und typische Befallssymptome werden beschrieben und abgebildet. Die Infektion erfolgte wahrscheinlich durch Erde, in der im Jahr zuvor Chrysanthemen wuchsen, die vonAphelenchoides ritzemabosi befallen waren.
Summary Aphelenchoides ritzemabosi has been recognised for the first time atFicus elastica andRodgersia aesculiformis too. Damages and typical symptoms of affected leaves are described. The infections atFicus elastica probably were due to the earth in which the year before grew Chrysanthemum attacked byAphelenchoides ritzemabosi.Samenvatting Aphelenchoides ritzemabosi werden voor het eerst ook vastgesteld aanFicus elastica enRodgersia aesculiformis. De schade en de typische symptomen van de aangevallen bladeren wordt beschreven. De infecties aanFicus elastica zijn waarschijnlijk te wijten aan de aarde in welke het jaar daarvoor Chrysanthemum groiden, die doorAphelenchoides ritzemabosi aangevallen waren.
Résumé Aphelenchoides ritzemabosi était constaté premièrement auxFicus elastica etRodgersia aesculiformis. Des dommages et des symptomes typique aux feuilles affectées sont déscrits. Les infections auxFicus elastica sont dues probablement à la terre dans laquelle l'année passée étaient planté des Chrysanthèmes saisis parAphelenchoides ritzemabosi.
(Aphelenchoides ritzemabosi) (Ficus elastica) (Rodgersia aesculiformis). . (Aphelenchoides ritzemabosi).
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3.
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  相似文献   

4.
Zusammenfassung Die Altlarven 2. Generation der AmpferblattwespeAmetastegia glabrata Fall. sind im Obstbau als Schädling bekannt. Die Schäden entstehen bei dem Versuch der Larven, in Früchten Puppenkammern anzulegen.Üblicherweise verpuppen sich die Larven in den trockenen Stengeln der Nährpflanzen(Polygonaceae) oder anderem trockenem oder verholzten Pflanzenmaterial.Es wird über einen gesicherten Fall berichtet, in demAmetastegia glabrata-Larven in verarbeitetem Nutzholz (Plakattafel) schädlich geworden sind. Ein weiterer Fall konnte nicht völlig geklärt werden; jedoch waren auch hier Blaltwespen-Larven in einer Wohnung in verarbeitetes Nutzholz (Türrahmen) eingedrungen.Nach dem geringen Umfang der Schäden, die nur durch die Anlage kurzer Puppenkammern in weichen Holzteilen entstehen, istAmetastegia glabrata in die Gruppe der gelegentlichen Holzzerstörer einzureihen. Allerdings kann durch diese Art völlig gesundes Holz im Freiland angegriffen werden.Holzschutzsalze vom U-Typ genügen zur Vorbeugung nicht. Vorbeugungs- und Bekämpfungsmaßnahmen werden besprochen.
Summary Attack on wood by larvae of the dock sawfly Ametastegia glabiata Fall. (Hym., Tenthiedinidae) Normally the mature larvae of the last brood of the dock sawfly bore themselves for pupation into dry stems of plants.By the gnawing efforts in certain years of appearance in masses, however, they may attack fruit too, especially apples, and cause considerable damage by numerous gnawing spots.Besides these known injuries on fruitA. glabrata has now been stated in two cases as an occasionally dangerous animal to dry timber too.The damage caused is described by word and picture; preventive and curative measures are discussed.
Résumé Attaque du bois par des larves de la Tenthrenidé Ametastegia glabrata Fall. (Hym., Tenthredinidae) Normalment les larves adultes de l'A. glabrata se forent dans les tiges sèches des plantes pour la mé tamorphose.Cependant aussi des fruits, surtout des pommes, sont attaqués par le ronger pendant les anées quand ces insectes paraîssent en masse. Des dommages considérables sont provoqués aux points d'attaque nombreux.A côté de ces dommages connus aux fruits l'A. glabrata a été constaté en deux cas comme causeur de dommage par occasion en bois sec de construction.Les dommages sont décrits et figurés; des methodes preventives et curatives sont discutées.
? Ametastegia glabrata Fall. (Hym., Tenthredinidae) . , , , . Ametastegia glabrata Fall. ( ) . , .

Mitteilung aus dem Holzschutzlaboratorium der Farbenfabriken Bayer AG., Werb Uerdingen  相似文献   

5.
Zusammenfassung Die SalatwurzellausPemphigus bursarius (L.)(Aphidoidea, Pemphigidae) gehört wegen ihrer unterirdischen Lebensweise zu den schwer bekämpfbaren Schädlingen, die in Salatkulturen regional starke Schäden verursachen können und von zunehmendem Interesse sind. In einem Befallsgebiet in Wolfenbüttel bei Braunschweig werden daher mehrjährige Untersuchungen zur Ermittlung der Bedeutung und geeigneter Bekä mpfungsmöglichkeiten der Salatwurzellaus durchgeführt. Bisher können über das Auftreten und die Bedeutung dieses Schädlings folgende Aussagen gemacht werden: Es besteht kein ursächlicher Zusammenhang zwischen dem Auftreten der Salatwurzellaus und zweier Salatvirosen (Salatmosaikvirus und Gurkenmosaikvirus). Sie alle traten unabhängig voneinander auf. Im Untersuchungsgebiet überwintertP. bursarius ausschließ lich an Pappeln, nicht dagegen im Ackerboden oder an Wurzelresten. Die Anfälligkeit verschiedener Salatsorten gegenüberP. bursarius ist nach den bisherigen Ergebnissen an 30 Sorten recht unterschiedlich, wobei die Sorten Hilmar, Kordaat, Unico, Kloek, Viktoria und Winter Butterkopf einen geringen oder gar keinen Befall zeigten, während die Sorten Wunder von Voorburg, Kagraner Sommer und Winter Mombacher stark befallen wurden. Diese Versuche müssen weitergeführt werden, bevor eine abschließende Beurteilung möglich ist. Die Schäden durch die Virosen, speziell das Salatmosaikvirus, sind in den Salatkulturen wesentlich schwerwiegender als die durchP. bursarius verursachten Verluste. Über Bekämpfungsversuche wird später berichtet.
Summary The lettuce root AphidPemphigus bursarius (L.)(Aphidoidea, Pemphigidae) belongs to the difficult controlable pests because of their subterranean mode of life. In lettuce cultures of certain regions this aphid can cause serious damages and therefore it is of increasing interest. In an area severely attacked byP. bursarius at Wolfenbü ttel near Braunschweig investigations are going on for several years to get to know the importance of this insect and to find out appropriate possibilities for its control. Up to now the following statements can be made concerning the appearance and the importance of this pest: There is no causal association between the lettuce root Aphid and two viroses of lettuce (lactuca virus 1 and cucumis virus 2). These pests appear independent from each other. In the investigated areaP. bursarius does hibernate only on poplars but not in the soil or on remaining roots. According to the hitherto existing results of 30 lettuce sorts the susceptibility of the various sorts againstP. bursarius is very different. The sorts Hilmar, Kordaat, Unico, Kloek, Viktoria and Winter Butterkopf did show a low or no attack, during the sorts Wunder von Voorburg, Kagraner Sommer and Winter Mombacher were severely attacked. These experiments must be continued before a definitive decision is possible. The damages in the lettuce cultures caused by the viroses, especially by lactuca virus 1, are more serious than those caused byP. bursarius. The control experiments are reported later.
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6.
Summary It is stated that in the spreading of epizooties among small wild animals, a factor of biocoenosis played a main role, first of all some phenomena among small rodents, the field mice. In the spreading of rabies infection, a role is ascribed to an insect, theNecrophorus vespillo.The author suggests a research work to be done in that respect, and perhaps in the regions where rabies was never registered and are still free of rabies, as to establish what in a such biocoenosis is lacking that could be a factor of rabies epizooty.
Résumé A l'extension de grandes épizooties chez les animoux féroces, on considère que le grand rôle joue le facteur de biocenose, tout d'abord certains phénomènes entre les menus rongeurs, souris de champs. On attribute surtout le rôle de l'extension de l'épizootie de rage à l'insectNecrophorus vespillo. On recommende de faire des recherches dans ce but avec les autres branches de sciences naturelles et peut-être dans ces regions du monde où il n'y en avait pas et il n'y a pas aujourd'hui de rage, pour établir ce qu'il manque dans une telle biocenose et que peut être pourrait on prendre en considération comme le facteur des épisooties de rage.
, — . Necrophorus vespillo L. . , .
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7.
Summary This paper studies the influence of the used creep function, and the duration of the experimental sustained loading from which the creep function was derived, in modelling the long-term buckling strength of timber columns. The sensitivity of this buckling strength to creep and initial deflection is numerically studied using an energy approach that takes into account the initial deflection. Various creep functions — power laws as well as exponential laws — derived from bending experiments of different durations are used for the numerical simulation. The crucial need for experimental results issued from very long load period experiments is identified. Such experiments may lead to a more credible creep analysis of timber structures.Symbols i radius of giration - s stress level - EL effective MOE - E0 instantaneous MOE - I inertia moment - K,K geometrical matrices - L length of beam or column - Lf effective length - Ncr axial force, buckling load - U elastic strain energy - W external forces work - t time variable - u moisture content (m.c.) - v total deflection - vc, ve, v0 creep, instantaneous elastic and initial deflections respectively Greek Letters (t) time function - , e, 0 total, instantaneous and initial strains respectively - twist rotation - (t) creep coefficient or fractional creep or relative creep - (x) shape function - load factor - longitudinal shortening - total potential energy - creep factor - relaxation time  相似文献   

8.
Cortes  Pilar  Espelta  Josep Maria  Savé  Robert  Biel  Carme 《New Forests》2004,28(1):79-88
The use of an enriched CO2 atmosphere in tree nurseries has been envisaged as a promising technique to increase productivity and to obtain seedlings with a higher root/shoot ratio, an essential trait to respond to water stress in Mediterranean-type ecosystems. In that framework, we have analyzed the effects of three levels of atmospheric CO2 concentration (350, 500 and 700ppm) on the germination rate, growth and morphology of seedlings of two Mediterranean oaks used in reforestation programs: the evergreen Quercus ilex L. and the deciduous Quercus cerrioides Wilk. et Costa. CO2 enrichment increased the germination rate of Q. cerrioides (from 70±7 to 81±3%) while it decreased that of Q. ilex (from 71±10 to 41±12%). Seedlings of both species increased approximately 60% their total biomass in response to CO2 enrichment but at two different CO2 concentrations: 500ppm for Q. cerrioides and 700ppm for Q. ilex. This increase in seedlings biomass was entirely due to an augmentation of root biomass. Considering germination and biomass partitioning, an enriched CO2 atmosphere might not be appropriate for growing Mediterranean evergreen oaks, such as Q. ilex, since it reduces acorn germination and the only gains in root biomass occur at a high concentration (700ppm). On the other hand, a moderate CO2 enrichment (500ppm) appears as a promising nursery technique to stimulate the germination, growth and root/shoot ratio of deciduous oaks, such as Q. cerrioides.  相似文献   

9.
Wood-based composites (medium density fiberboard, hardwood plywood, softwood plywood, particleboard, and oriented strand board) treated with a mixture formulation of 3-iodo-2-propynyl butylcarbamate (IPBC) and silafluofen using supercritical carbon dioxide as a carrier solvent were evaluated for their resistance to biological attack in a laboratory study. The formulation was pre-pared by mixing 10g of IPBC and 1g of silafluofen in ethanol solution (20ml). Treatments were conducted at 35°C/7.85MPa, 35°C/9.81MPa, and 55°C/11.77MPa with the direct introduction of 20ml of the formulation into the treatment vessel with a capacity of ca. 2000ml at a rate of 2ml/min. Laboratory tests indicated that the treatment conditions used significantly enhanced the resistance of the treated wood-based composites against fungal and termite attacks. Because no significant difference in efficacy against both biodegrading agents was noticed regardless of the treatment conditions, the treatment at 35°C/7.85MPa was thought to be the most economical in terms of energy consumption and performance of treated materials. However, the amount of biocides in a formulation must be carefully selected in accordance with the required treatment condition to ensure satisfactory performance of the treated wood-based composites against any biological agent.  相似文献   

10.
Zusammenfassung 1. Es wurden Hydroponikkulturen der Ziernessel mit 11 verschiedenen Insektiziden (Chlorierten Kohlenwasserstoffen, Phosphorsäureestern und Carbamaten) behandelt.2. Die Insektizide wurden bei bewurzelten und unbewurzelten Sprossen über die Nährlösung appliziert und nach verschieden langer Dauerkultur Extrakte von Blättern, Sprossen und Wurzeln auf ihre insektizide Wirkung im Biotest(Drosophila melanogaster) überprüft.3. Allgemein war die Kontaktwirksamkeit der Wurzelextrakte hoch, während Sproß- und Blattextrakte nur bei systemischen oder ähnlich wirkenden Mittein Wirkungen beobachten ließen. Hierbei erwies sich das Carbamat Isolan als besonders blattwirksam.4. Durch Vergleich mit Kontrollextrakten unbehandelter Pflanzen konnte eine unterschiedliche Maskierung der WS durch die Lipoide gezeigt werden. Blattlipoide waren erheblich wirksamer bezüglich der Abfangpotenz als Wurzelextrakte.5. Da jedoch diese Kontrollextrakte eine Eigentoxizität fürDrosophila beobachten ließen, wird die Beachtung solcher Störwirkungen gefordert und auch bei Modellversuchen, wie den hier angestellten, eine Reinigung der Extrakte vor den Biotesten vorgeschlagen.
Summary Bioassay with crude plant extracts(Coleus blumei) after basal treatment with insecticides in hydroponic culture resulted differenciated contact activity. 11 insecticides (and acaricides) have been investigated in commercial formulation (emulsion and wettable powder, application of different concentrations via mineral salt solution). Apical treatment with insecticides (spray- application) will be reported in later papers.Leaf, stem and root of isolatedcoleus developed contact reactions in extracts forDrosophila melanogaster M. (Rutshurel, sensitive and Göttingen, sensitive). Leaf-extracts after basic treatment with Isolan, Parathion, Diazinon, Demeton-o-methyl and Malathion caused high contact effects. Lower intensities are recovered in leaves after application (via roots) of Lindane and Trichlorphon (Dipterex®). Additions of DDT-formulations and Phenkapton are causing poisoning action of root extracts only and Chlorobenzilate was not effective onDrosophila. All other insecticides showing high poisoning in root extracts, resulted insecticidal actions in stem extracts regarding the degree of systemic properties. Thiodan is less active in that response than Lindane and the typical systemic substances as Isolan, Demeton-o-methyl etc.Some of the reactions could be regarded as well as action of the insecticidal substance as possible effect of formula. The bioassay of pesticides residues in crude extracts is serviceable under certain circumstances. It is proposed that better and more instructive information should be obtained by tracer-substances or by cleaning and separating procedures of the extracts (chemical methods) and subsequent bioassay.
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11.
Zusammenfassung DurchRickettsiella melolonthae (Krieg) PHILIP infizierte Maikäfer-Engerlinge wandern während des Spätherbstes und Winters im Freiland absterbend auf die Erdoberfläche. Als Begleitarten inMelolontha Larvenpopulationen kamen im Gebiet vor:Amphimallon solstitiale (L.),Anomala dubia aenea (DeG.) undMaladera brunnea (L.). MitR. melolonthae künstlich infiziert, zeigten sie im Orientierungsversuch die gleiche Aufwanderungstendenz wie kranke Maikäferengerlinge, am deutlichsten die vonM. brunnea. Auf dem Waldboden fanden sich kranke Larven dieser Art in einigen Fällen.
Summary Larvae ofMelolontha spp. infested withRickettsiella melolonthae (Krieg) PHILIP move during October– January to the top of the soil where they eventually die. Larvae ofAmphimallon solstitiale (L.),Anomala dubia aenea (DeG.) andMaladera brunnea (L.) are susceptible forR. melolonthae, too. In experiments, artificially infested individuals showed a similar tendency to move upward. This was most pronounced inM. brunnea, of which some infested larvae were found on the forest floor.
Résumé Larves du hanneton, infectées parRickettsiella melolonthae (Krieg) PHILIP, se rendent à la surface de la terre au fin de l'automme et dans l'hivers. Comme espèces accompagnant les populations larvaires deMelolontha nous avons trouvés:Amphimallon solstitiale (L.),Anomala dubia aenea (DeG.) etMaladera brunnea (L.). Ils out démonstré, après une infection artificielle avecR. melolonthae, la mème tendence dans les essais d'orientation comme les vers blancs malades deMelolontha. Le phé nomène etait le plus prononcé parmi les larves deMaladera. De cette espèce nous avons trouvés plusieurs larves malades à la surface de la terre en plein champs.
Rickettsiella melolonthae (Krieg) Philip Melolontha- . . Melolontha- :Amphimallon solstitiale (L.),Anomala dubia aenea (De G.) Maladera brunnea (L.). R. melolonthae , Melolontha-, M. brunnea. .
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12.
To quantify the nitrogen (N) use by Pinus densiflora trees growing on an infertile lava surface, N pools, N requirement and N uptake through fine roots and N deposition from the atmosphere were estimated. The N requirement and the N uptake of fine roots were 55.5kgNha–1year–1 and 39.7kgNha–1, respectively. Thus, the ratio of N uptake to N requirement of the fine roots was 71.5%. Including fine-root contribution, the total N requirement of the P. densiflora trees was 98.6kgNha–1year–1, and the total N uptake was 64.2kgNha–1year–1. Thus, the N uptake of the P. densiflora trees was 64.1% of the N requirement, indicating that P. densiflora trees growing on an infertile lava surface obtain some of their N from below-ground organic material layers every year and the contribution of N storage in trees for their growth is not any higher than indicated in previous reports that excluded fine-roots contribution. The wet N deposition of our research forest was only 5.8% of the N requirement of the P. densiflora trees and only 8.9% of the N uptake. Movement of the below-ground organic material layer N concentrations in the F- and L-layers coincides with needle development and fine-root growth, suggesting the possibility that P. densiflora trees extract N from the organic N of those layers for growth.  相似文献   

13.
Summary An analysis is given which enables the shear strain in a piece of timber to be specified in terms of the difference between tangential and radial strain, herein termed the angular strain. The angular strain is then evaluated in terms of the orientation of two lines at right angles prior to deformation. The equations involved are simple and facilitate the evaluation of strain parameters which would otherwise require numerical computation.Symbols a, b, c length parameters, Fig. 2 - C half chord length - k constant of proportionality - r radial coordinate (distance from pith) - x length coordinate (board) - , angle parameters, Fig. 1 - shear strain - width of segment - angular strain - #x025B; tangential strain - r radial strain - 1, 2 components of shear strain, Fig. 1 - angle parameter, Fig. 2 - angle parameter, Fig. 3 - angle parameter, Fig. 2 The author wishes to thank Mr. J. W. Sutherland for his assistance with the presentation of this paper.  相似文献   

14.
Summary Larvae ofErnobius spp. and adults ofBrachyderes incanus were serious pests of shoots ofPinus silvestris andP. contorta at several localities of Rhine valley and near Meppen/Ems.In the same areas aphids(Lachninae) and their predators were very abundant.Protolachnus agilis Kltb. became very harmful on young pines in experiment field cages where predators had been excluded.Pineus sp. was frequent in the field cages and in young pine plantations near Meppen.
Résumé En divers endroits de la vallée du Rhin et près de Meppen/Emsland, des larves d'Ernobius spp. et des adultes deBrachydeles incanus furent observés comme étant de sérieux pour les jeunes pousses dePinus silvestris et deP. contorta.Dans les mêmes régions des pucerons(Lachninae) et leurs prédateurs étaient très abondants.Protolachnus agilis Kltb. divint très nuisible aux jeunes pins placés dans des cages expérimentales où les prédateurs avaient été enfermés.Pineus sp. é tait aussi abondant dans cages expérimentales et dans les plantations de jeunes pins près de Meppen.
Meppen/Emsland Eronobius spp. Brachyderes incanus, Pinus silvestris P. contorta. (Lachninae) Protolachnus agilis Kltb. , - .Pineus sp. - Meppen.
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15.
Summary Natural enemies of Euproctis chrysorrhoea in orchards in Yugoslavia During an outbreak ofEuproctis chrysorrhoea in orchards near Kosovo, Yugoslavia, several parasites (Larvaevoridae and Ichneumonidae especiallyApanteles), predators (Coleoptera of the generaCantharis andMalachius) as well as a protozoic disease were observed attacking the pest. The disease agent was recognized to be a new species:Nosema kovaevii sp. n. (Microsporidia). The cycle of development of the new species is described. Opposite to related species the spores ofN. kovaevii show a great variety in length.  相似文献   

16.
Zusammenfassung In einer zweijährigen Versuchsserie wurde die Wirkung der Schutztauchung von Nadelholzpflanzen in DDT, Lindan WP und Lindan EC (1% a. S.) gegen Befall des Rüsselkäfers (Hylobius abietis L.) untersucht. Die Versuche wurden auf 43 Forstkulturen in ganz Schweden ausgeführt.Die Versuche bestätigten, daß der Rüsselkäfer im allgemeinen im südlichen und mitteren Schweden wesentlich stärker auftritt als in kälteren nördlichen Gebieten. In allen geographischen Regionen hatten die Insektizidbehandlungen gute Schutzwirkung während 2 Vegetationsperioden. Die Unterschiede in der Wirkung der 3 Präparate waren relativ gering. Lindan schützte die Pflanzen in beiden Vegetationsperioden mindestens ebenso gut wie DDT. Das beste Mittel war im allgemeinen Lindan WP. Nachhaltig ungü nstige Einflüsse der Präparate auf die Pflanzen wurden nicht nachgewiesen.
Summary Field experiments with insecticides against pine weevils (Hylobius abietis L.) in Sweden.The protection of conifer plants against attacks of the pine weevil (Hylobius abietis L.) by dipping in DDT, lindane WP and lindane EC (1% a. i.) was studied during two years. The experiments were carried out in 43 reforestation areas all over Sweden.The experiments confirmed that pine weevil attacks as a rule are considerably heavier in Southern and Central Sweden than in cooler, more northerly regions. In all regions the treatments with insecticides had a good protective effect during two vegetation periods. The differences in effect between the three insecticides were comparatively small. In both vegetation periods lindane gave at least as good protection as did DDT. Lindane WP was generally the best formulation. The experiments did not reveal any persistent negative effects of the treatments on the plants.
(Hylobius abietis L.) . (Hylobius abietis L.) 43- . (1% ). , , . . - . . . - .

Forstliche Hochschule, S 10 405 Stockholm 50/Schweden.  相似文献   

17.
Five heavy metals in the propagules of 10 mangrove species in China have been investigated. The results revealed that the levels of five heavy metals in most of the propagules were lower than the background levels of the soil. The levels of copper, manganese, zinc, cadmium, and lead in the propagules varied at about 2.1–7.8 g/g, 3.9–28.0 g/g, 5.7–60.0 g/g, 0.014–0.057 g/g, and 0.018–0.038 g/g, respectively. On average, the levels of five heavy metals were in the order Zn > Mn > Cu > Cd > Pb. The biological absorption coefficients were 0.02–1.30 for copper, manganese, zinc, and cadmium and about 0.0007–0.0020 for lead in propagules, showing the following order: Zn > Cd > Cu > Mn > Pb. The above results indicate that the five heavy metals have low accumulation in most of the propagules of 10 mangrove species and are at safe levels for the effective utilization of mangrove resources.  相似文献   

18.
Zusammenfassung In Freiland- und Laborversuchen wurde die Wirkung des Pflanzenschutzmittels Sevin auf Regenwürmer untersucht. Dieser Stoff ist in Pulverform und als Suspension für diese Organismen außerordentlich gefährlich. Schon der Kontakt mit sehr geringen Mengen bewirkt schwere Lähmungserscheinungen und irreversible histopathologische Schäden.
Summary Experiments in the field as well as in the laboratory showed up the effect of the pesticide Sevin on rainworms. In the form of powder as well as a suspension this material is extremely toxic for them. Contact with smallest quantities even causes severe paralysis and irreversible histopathologic damages.
Résumé Aussi bien dans la nature que au laboratoire nous avons étudié l'activité de l'insecticide Sevin sur les vers de terre. Ce produit est en poudre ou en suspension extrémement dangereux pour ces organismes. Le seul contact avec des quantités minimes de ce produit provoquent des phénomènes de paralysie et des troubles histopathologiques irreversibles.
SEVIN . . .
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19.
A new relaxation property is discussed on the basis of creep behavior of wet wood specimens pretreated with heating at various temperatures followed by quenching. The treated samples showed more marked relaxation than that of an untreated sample. The relationship between relaxation time and heating history was represented by an equation ln() = –( f – k 1)T + [ln( g) + k 2], where ln() is the logarithmic relaxation time of wet samples after quenching, T is the difference between the heating temperature and the glass transition temperature (T g), ln( g) is the logarithmic relaxation time at T g, is a constant, f is the coefficient of thermal bulk expansion, and k 1 and k 2 are constants. It was concluded from the analysis of experimental results that the change in the relaxation property caused by heating and the following quenching is due to the temporary free volume created by freezing of molecular chain motion of wood components, most probably lignin, during quenching.This work was presented at the 52nd Annual Meeting of Japan Wood Research Society, Gifu, April 2002  相似文献   

20.
The effect of a fogging system on interactions between Tetranychus urticae and Phytoseiulus persimilis was studied in two cucumber greenhouses in northern Italy. The greenhouses were divided into two compartments, one (referred to as fog area) was humidified using a fogging system and the other was not humidified (no fog area). Four cultivars were investigated: Akito and Frontera during 2000, Dinero and Jazzer during 2001. Tetranychus urticae was released on a number of plants in both compartments. The release of P. persimilis was planned in both compartments at definite T. urticae thresholds. Phytoseiid releases failed, and the colonization by other predators was scarce.Thus, the effect of the fogging system was evaluated only on T. urticae populations. During the first experimental year, spider mite populations reached low densities in the fog area of both cultivars. Higher densities were found in the no fog area, especially in late June and early July. One year later, spider mites were more abundant in the no fog area of the Dinero cultivar. On the Jazzer cultivar, where most plants were infected by powdery mildew, spider mites were less abundant and differences between the two areas were less marked. Since relative humidity values exceeding 90% (considered as effective on T. urticae) were recorded during the night when the fogging system was not active, we suggest that contact with misty water was the main factor responsible for the reduction of T. urticae populations in the fog area.  相似文献   

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