Über neue Wirtspflanzen der BlattälchenAphelenchoides fragariae undA. ritzemabosi,mit Bemerkungen zu den Wirtspflanzenkreisen beider Nematodenarten

Zusammenfassung Bei Untersuchungen, die an mehreren Orten im bayerischen Gebiet durchgeführt wurden, konntenAphelenchoides fragariae undA. ritzemabosi an zahlreichen Pflanzen als Parasiten festgestellt werden. FürA. fragariae wurden 46, fürA. ritzemabosi 31 vermutlich noch unbekannte Wirtspflanzen gefunden. Insgesamt sind damit vomA. fragariae mindestens 256, vonA. ritzemabosi mindestens 160 Wirtsarten bekannt. Eine Zusammenstellung s?mtlicher Wirtspflanzenfamilien beider Blatt?lchenarten mit Anzahl der zugeh?rigen anf?lligen Pflanzenarten la?t eine Bevorzugung bestimmter Pflanzenfamilien und-gattungen erkennen.A. fragariae bef?llt vorwiegend Farne, Liliaceen, Ranunculaceen, Primulaceen, wogegen A. riB emabosi vor allem die Compositen bevorzugt. Welche Faktoren die Wirtswahl und das unterschiedliche Verhalten beider Blatt?lchenarten bestimmen, ist noch weitgehend ungekl?rt. Die Auspr?gung der Befallssymptome h?ngt im Wesentlichen von Bau- und Reaktionsweise der befallenen Pflanzenteile ab und ist zwischen beidenAphelenchoides-Arten nicht wesentlich verschieden.     

不同密度杉木幼林系统生产力和生态效益研究

杉木幼林系统是由４个不同密度级处理系列小区组成,栽植密度为１６６５、３３３０、４９９５和６６６０株／ｈｍ＾２（以下分别用Ａ、Ｂ、Ｃ和Ｄ代替）。这些小区土壤质地及地形别无二致,都是用１年生实生苗１９８７年春天定植。８年生时调查了这些幼林系统林木生长、冠层厚度、枝下高以及生态效益等。随着密度由Ａ增加到Ｄ：平均胸径生长量从８．１ｃｍ降到６．６ｃｍ;平均树高生长量由５．９ｍ降至５．４ｍ;平均冠层厚度自４．     

Influence of mixed biocide GCSC-BtA on the pupae and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host. Plutella xylostella (L.) (Lep., Plutellidae)

This paper deals with the influence of the mixed biocide GCSC-BtA on the pupal and adult stages of Apanteles plutellae Kurd. (Hym., Braconidae) and its host, Plutella xylostella (L.) (Lep., Plutellidae). The results show that mortalities of the pupae of P. xylostella in the direct-dip bioassay were 84.67?%, that of the adults in the residue bioassay at 1.2500?mg/ml concentration of GCSC-BtA were 78.00?% which were significantly higher than the mortality values for the pupae with 54.62?% and adults with 48.13?% of A. plutellae. In contrast, cypermethrin showed extremely high toxicity to the pupae with 94.58?% and adults with 86.00?% mortality values of A. plutellae as compared to the low mortality values of 42.14?% for the pupae and 32.11?% for the adults of P. xylostella, with the same concentrations and bioassay methods. The LC₅₀ values of GCSC-BtA were 0.3402, 0.5516 and 1.2405, 1.9480?mg/ml for the pupae and adults of P. xylostella and A. plutellae, respectively, while the LC₅₀ values for cypermethrin were 1.5652, 2.3471 and 0.1096, 0.1152?mg/ml, respectively. GCSC-BtA was found more toxic to the pupae and adults of P. xylostella and safer to the pupae and adults of A. plutellae than cypermethrin. The possibilty of using GCSC-BtA against P. xylostella under partial control by A. plutellae in vegetable fields is discussed.     

Erfahrungen bei der Bekämpfung der RübsenblattwespeAthalia colibri Christ (=A. rosae L.) mit Toxaphen,E 605, Systox und Metasystox

Zusammenfassung Die Wirkung der Mittel Toxaphen, Systox, Metasystox und E 605 f gegen die Larven der RübsenblattwespeAthalia colibri Christ wurde geprüft. Elne einmalige Spri?ung mit 0,5%igem Toxaphen t?tete nur wenige Larven ab, hatte aber eine deutlich abschreckende Wirkung. Durch eine zweite Behandlung mit 0,2%igem Toxaphen konnte der Fra? nur soweit beeinflu?t werden, da? die Senfpflanzen etwa 50–60% ihres Blattwerkes verloren, v?lliger Kahlfra? also nicht zustande kam. Das gleiche Ergebnis wurde bei Verwendung von Systox (0,05%) und Metasystox (0,1%) erzielt. E 605 f (0,02%) schnitt weitaus am besten ab; schon am Tage nach der Behandlung war eine 100%ige Abt?tung derA. colibri-Larven zu verzeichnen. Das zule?t genannte Mittel ist nach wie vor das cinzige gebr?uchliche, das zurA. colibri-Bek?mpfung empfohlen werden kann. Bei der Behandlung von blühendem Senf sind jedoch Vorsichtsma?nahmen zur Vermeidung von Bienenverlusten erforderlich. Die Spri?ung von Metasystox und Systox in den blühenden Senf hatte keine Bienenverluste zur Folge, wenn die Mittel am Abend nach Aufh?ren des Bienenfluges angewendet wurden.     

孟加拉国Madhupur林区内不同森林树种中丛枝菌根多样性的研究

从 Madhupur 林区的不同地点采集了 Acacia auriculi-formis A. Cunn. ex Benth., A. mangium Wild., Artocarpus het-erophyllus Lamk. C., Dalbergia sissoo Roxb. ex A. P. D., Euca-lyptus camaldulensis Dehnn., Hevea brasiliensis (Wild. ex Juss) Muell. Arg., Swietenia macrophylla King. and Tectona grandis L. 8个树种的根和根际土。采用简单常规的根围土壤真菌孢子分离、形态鉴定和树木细根染色、显微镜观察等方法,进行了孟加拉国Madhupur林区内不同森林树种中丛枝菌根多样性的研究。图2表2参46。     

Nachweis der GattungArmillaria (Fr.:Fr.) Staude undHeterobasidion annosum (Fr.) Bref. in Fichte (Picea abies [L.] Karst.) und Erfassung der klonalen Ausbreitung vonA. ostoyae-Genotypen unter Verwendung molekularer Methoden

Zusammenfassung Methoden zur Entwicklung molekularer Marker mit Hilfe der Polymerase-Kettenreaktion (PCR) werden beispielhaft an den beiden forstlichen PathogenenArmillaria spp. undH. annosum erl?utert. Unter Verwendung der aus „internal transcribed spacer“ (ITS)-DNA-Sequenzen abgeleiteten Primerpaare ARM-1/ARM-2 bzw. HET-7/HET-8 konntenArmillaria spp.- bzw.H. annosum-spezifische DNA-Abschnitte mittels PCR amplifiziert werden. Diese PCR-Diagnosemethode erlaubt einen schnellen und effizienten Frühnachweis dieser beiden forstlich relevanten Wurzel- und Stockf?uleerreger in verschiedenen Substraten bzw. Pflanzengeweben. Die genetische Variabilit?t von 20A. ostoyae-Isolaten aus verschiedenen geographischen Herkunftsgebieten wurde untersucht. Die UPGMA-Clusteranalyse der unter Verwendung von 10 Decamer-Zufallsprimern (OPA 01-10) erhaltenen „random amplified polymorphic DNAs“ (RAPDs)-Muster gruppierte die Isolate in Untergruppen mit 40–96% ?hnlichkeit, was auf eine hohe intraspezifische genetische Variation hindeutet. Die potentielle Rolle der historischen und gegenw?rtigen Ausbreitung von Fichtenpflanzen für die genetische Variation vonA. ostoyae in Europa wird diskutiert. Die aufgefundenen polymorphen DNA-Marker wurden für die Erfassung der Populationsstruktur bzw. -dynamik sowie der r?umlichen Ausbreitung vonA. ostoyae-„genets“ in ausgew?hlten Befallsgebieten genutzt. Erste Untersuchungen haben unterschiedliche Ausbreitungsstrategien vonA. ostoyae in Abh?ngigkeit von Klima-, Standort- und Immissionsfaktoren aufgezeigt.      

How does drought tolerance compare between two improved hybrids of balsam poplar and an unimproved native species?

Poplars are one of the woody plants that are very sensitive to water stress, which may reduce the productivity of fast-growing plantations. Poplars can exhibit several drought tolerance strategies that may impact productivity differently. Trees from two improved hybrids, Populus balsamifera?×?Populus trichocarpa Torr. & Gray (clone B?×?T) and P. balsamifera?×?Populus maximowiczii A. Henry (clone B?×?M), having P. balsamifera L. as a parent and trees from native and unimproved P. balsamifera were subjected to a 1-month drying cycle in a growth chamber and then rewatered. The unimproved and native B clone maintained higher stomatal conductance (g(s)) than the hybrids, and high photosynthetic activity and transpiration, even when soil water content was nearly zero. As a result, both instantaneous water use efficiency (WUE(i)) and leaf carbon isotope composition (δ(13)C) indicated that this clone was less affected by drought than both hybrids at maximal drought stress. However, this clone shed its leaves when the drought threshold was exceeded, which implied a greater loss of productivity. The B?×?M hybrid showed a relatively conservative response to water stress, with the greatest decrease in transpiring versus absorbing surface (total leaf area to root biomass ratio). This clone was also the only one to develop new leaves after rewatering, and its total biomass production was not significantly decreased by drought. Among the two hybrids, clone B?×?T was the most vigorous, with the greatest transpiration (E(i)) and net CO(2) assimilation (A) rates, allowing for high biomass production. However, it had a more risky strategy under drought conditions by keeping its stomata open and high E(i) rates under moderate drought, resulting in a lower recovery rate after rewatering. The opposite drought response strategies of the two hybrids were reflected by clone B?×?T having lower WUE(i) values than clone B?×?M at maximal drought, with a very low Ψ(min) value of -3.2 MPa, despite closed stomata and stopped photosynthetic activity. Positive linear relationships between A and g(s) for the three hybrids indicated strong stomatal control of photosynthesis. Moreover, the three poplar clones showed anisohydric behaviour for stomatal control and their use under long-term drought should be of interest, especially the B?×?M clone.     

Investigations on side-effects of the mixed biocide GCSC-BtA on different predators of Plutella xylostella (L.) (Lep., Plutellidae) in southeastern China

The present paper deals with laboratory studies on side-effects of the mixed biocide GCSC-BtA on Plutella xylostella (L.) (Lep., Plutellidae) and its predators, e.?g. Amblyseius longispinosus (Evans) (Acari, Phytoseiidae), Erigonidium graminicola (Sundvall) (Araneae, Linyphiidae), Orius similis Zheng (Het., Anthocoridae) and Coccinella septempunctata L.(Col., Coccinellidae), in comparison to the commercial insecticides, e.?g. Abamectin, Tebufenozide, Dichlorvos, Cartap and Lambda-cyhalothrin. The results showed that GCSC-BtA was highly toxic to the 3^rd instar of P. xylostella with 91.18?% mortality, followed by Cartap with 84.38?%, Abamectin with 78.00?%, Tebufenozide with 75.57?%, Lambda-cyhalothrin with 63.75?% and Dichlorvos with 50.86?% mortality. On the other hand, GCSC-BtA was found to be comparatively less toxic to the predators, causing 31.11?%, 13.33?%, 11.54?% and 6.00?% mortalities in A. longispinosus, E. graminicola, O. similis and C. septempunctata, respectively. For comparison, the mortalities recorded for Abamectin, Tebufenozide, Dichlorvos, Cartap, Lambda-cyhalothrin were 72.94?%, 55.55?%, 70.00?%, 53.26?% and 98.85?% in A. longispinosus, 46.51?%, 55.10?%, 60.00?%, 46.00?% and 73.68?% in E. graminicola, 22.00?%, 16.00?%, 35.71?%, 26.78?% and 81.03?% in O. similis, 15.55?%, 19.64?%, 28.00?%, 16.66?% and 41.79?% in C. septempunctata, respectively. Cluster analysis was introduced to group the mortalities caused by the treatments into three toxicity groups with the distance of D?=?4.1. The 1^st group consisted of GCSC-BtA characterized with low toxicity to all the predators tested with 15.49?% mortality on average (highest 31.11?% and lowest 6.00?%). The 2^nd group consisted of Abamectin, Tebufenozide, Dichlorvos and Cartap with moderate toxicity to the predators with 39.96?% mortality on average. The 3^rd group included Lambda-cyhalothrin with high toxicity to the predators with 73.83?% mortality on average (highest 98.85?% and lowest 41.70?%). The susceptibility of the pest and its predators to GCSC-BtA and the insecticides is discussed. GCSC-BtA as a biological control agent is recommended for use in the integrated pests control programs in the vegetable fields.     

木荷优良家系的组织培养研究

以新选育的木荷（Schima superba）优良家系为试材,开展组织培养。结果表明,木荷适宜的初代培养基为GD+6-BA 1.50 mg·L-1+NAA 0.50 mg·L-1,继代培养基为GD+6-BA 1.00 mg·L-1+ IAA 0.30mg·L-1,生根培养基为1/4 MS+ IBA 1.00 mg·L-1+IAA 0.40 mg·L-1。芽苗增殖倍数为3.1倍,生根率达96.67％。探索出适宜的驯化、移栽和后期管理技术,使优良家系生根苗的移栽存活率达到92.2％。     

Effect of shading by baobab (Adansonia digitata) and néré (Parkia biglobosa) on yields of millet (Pennisetum glaucum) and taro (Colocasia esculenta) in parkland systems in Burkina Faso, West Africa

An experiment was conducted in Nobéré, Burkina Faso to assess the effect of shade of two indigenous fruit trees, Adansonia digitata (Baobab) and Parkia biglobosa (Néré), on a shade-tolerant crop called taro (Colocasia esculenta) in comparison with millet (Pennisetum glaucum) a shade-intolerant crop. Photosynthetically active radiation (PAR) and performance of crops under trees and in the open field were assessed during three cropping seasons. Millet performed better under baobab (806.1?±?121.48?kg?ha^?1) compared to the control plot (595.8?±?83.43?kg?ha^?1) and néré (320.2?±?59.91?kg?ha^?1). In contrast, the yield of taro was higher under néré (4124.0?±?469.05?kg?ha^?1) compared to the control plot (2336.9?±?617.04?kg?ha^?1) and baobab (2738.3?±?595.61?kg?ha^?1). There was a strong relationship between the amount of PAR intercepted by trees and crop yields under trees. As PAR decreased the yield of millet decreased whereas the yield of taro increased. Hence, it was concluded that parkland productivity could be enhanced by cropping taro under néré where light reduction was 83, 56 and 18% in zones A, B and C, respectively. An efficient association of baobab with crops could be the production of taro in zone A and millet in zones B and C where PAR reduction was 62, 38 and 15%, respectively.     

Populations of aphids, whiteflies and associated predators and parasites on different vegetables cultivated in plastic greenhouses

During 1996 and 1997, populations of aphids and whiteflies and their parasites were studied in plastic greenhouses under a chemical control program and in those free of pesticides. In the greenhouses free of pesticides, the parasite A. colemani destroyed 14.7?% of the aphids. B. tabaci had no effect on the cucumbers during the spring cultivation. However, it attacked the autumn cultivation. The parasite E. mundus killed 30?% of these nymphs. The parasite A. colemani parasitized up to 10?% of aphids on tomato plants in greenhouses free of chemical pesticides. The parasite E. mundus killed 15.7?% of whitefly nymphs. In greenhouses under a chemical pesticides program, aphids and whiteflies were found on the plants at the end of the plantation season, after the pesticide spraying had stopped. Although the pest population was low, the parasite A. colemani parasitized 8?% of the aphid population. Whiteflies were not found on tomato plants in greenhouses under extensive pesticides use.     

The thermal constant for timing the emergence of the Red Palm Weevil, <Emphasis Type="Italic">Rhynchophorus ferrugineus</Emphasis> (Oliv.) (Coleoptera,Curculionidae)

The pupal duration of the red palm weevil, Rhynchophorus ferrugineus (Oliv.) at two different temperatures revealed that the thermal threshold is –?2.3?°C, while the thermal constant is 423 degree days. Around 20.7 cycles of weevil emergence per year have been predicted in Egypt. A temperature between 44?–?45?°C was found to be the higher threshold at which the pupae are killed. The heat units required for the pupal development were utilized to predict the dates of adult emergence throughout the year.     

Ecophysiology of Acacia species in wet–dry tropical plantations

Selected tropical Acacia species are used extensively for short-rotation plantation forestry in many parts of Asia and, to a limited degree, in Australia. We explored leaf-level photosynthetic activity and leaf water potential (Ψleaf) of three field-grown Acacia tree species (aged between 7 and 18 months) in contrasting wet–dry tropical plantations in southern Vietnam and northern Australia. Light-saturated photosynthetic rate (A1500) declined throughout the morning and early afternoon in the dry season; in the wet season, levels remained high and relatively constant throughout most of the day. Maximum daily A1500 at 09:00 ranged from 22.2 μmol?m?2?s?1 in the wet to 10.4 μmol?m?2?s?1 in the dry season. At both locations, trees were able to extract soil water such that pre-dawn leaf water potential (Ψpd) remained>?1.5?MPa even at the end of the dry season. Stomatal conductance to water vapour (gs) did not respond to decreasing Ψleaf during the wet season but was sensitive to changes in Ψleaf in the dry season. Species comparisons of the relationships between A1500 and Ψleaf revealed different strategies to balance carbon uptake and water loss in a wet–dry environment. Acacia crassicarpa and A. mangium regulated Ψleaf to a greater extent than the A. mangium×A. auriculiformis hybrid such that ?Ψleaf (determined as Ψpd?midday Ψleaf) was unaffected by season. This result suggests that the hydraulic regulation of tree water status varies amongst young tropical Acacia species. From a management perspective, for Acacia species that tend to strongly regulate water loss in environments with an extended dry season, overall productivity at the end of a rotation may be less than for species that prioritise carbon gain.     

Ergebnisse einer Probebekämpfung verwilderter Haustauben

Zusammenfassung Bei einer Probebek?mpfung verwilderter Haustauben an 7 verschiedenen ?rtlichkeiten von West-Berlin wurden 418 Tiere get?tet, von denen anschlie?end durch Sektion Geschlecht und Alter festgestellt wurde. Bei den Jungtauben war das Geschlechtsverh?ltnis fast ausgeglichen, w?hrend unter den alten Tauben die M?nnchen stark in der überzahl waren. Diese einseitige Verschiebung der Geschlechtsproportion beruht vornehmlich darauf, da? z. Zt. der Bek?mpfung noch viele Weibchen auf ihren Nestern sa?en und nicht zur Futterstelle gekommen waren. Das verschiedene Verhalten der einzelnen Taubenschw?rme w?hrend der Fütterung wird beschrieben.

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Summary A campaign against feral pigeons on 7 public places in Berlin-West has had a result of 418 dead animals. The carcasses were sexed and aged. In the entire sample each sex of the young pigeons was represented in a fairly eaqual proportion. Among the mature pigeons the males dominated considerably. This is a result of the breeding behaviour in so far, as during the control measures early in the morning the doves were still sitting on their nests and did not appear on the feeding places. The different behaviour of the flocks during their feeding was discussed.

     

Changes in topsoil, standing litter and tree nutrient content of a Pinus patula plantation after phosphorus and potassium fertilization

A major goal for sustainable forestry management is to prevent a decline in soil fertility over time. The impact of phosphorus (P) and potassium (K) fertilization on the nutrients in the foliage, standing litter and topsoil (0 to ?10?cm) at the end of the third crop rotation (at age 15?years) was determined. Three quantities (20/20, 40/40 and 80/80?kg?ha^?1) of both P and K fertilizer was applied at different stages of stand development (all at planting, all post-pruning at age 5?years, or applying 20/20 at planting and the rest post-pruning). The results showed that the effect of P fertilizer was more pronounced than the effect of K fertilizer. Compared to the control, the application of 80/80 PK fertilizer increased the concentration of plant available P (Bray II) in the first ?10?cm of the topsoil from 3 to 12?mg P kg^?1 and increased the foliar P level to 0.13%. The foliar P as well as the concentration of plant available P in the topsoil increased when the fertilizer was applied post-pruning. The split application of either 40/40 or 80/80 PK fertilizer increased the stemwood P concentration by 50%, compared to the 23?mg P kg^?1 on the control plots. Application of the 40/40 and 80/80 quantities of fertilizer increased the dry mass (DM) of the standing litter layer by 27?Mg DM ha^?1 (35%), which also affected the P and K content per hectare. A larger proportion of the applied fertilizer-K than fertilizer-P was removed from the site in stemwood and stembark, indicating that the re-application of K in the subsequent rotations will be important for sustainable production.     

Seasonal fluctuations and temperature dependence in photosynthetic parameters and stomatal conductance at the leaf scale of Populus euphratica Oliv

A combined model to simulate CO? and H?O gas exchange at the leaf scale was parameterized using data obtained from in situ leaf-scale observations of diurnal and seasonal changes in CO? and H?O gas exchange. The Farquhar et al.-type model of photosynthesis was parameterized by using the Bayesian approach and the Ball et al.-type stomatal conductance model was optimized using the linear least-squares procedure. The results show that the seasonal physiological changes in photosynthetic parameters (e.g., V(cmax25), J(max25), R(d25) and g(m25)) in the biochemical model of photosynthesis and m in the stomatal conductance model should be counted in estimating long-term CO? and H?O gas exchange. Overall, the coupled model successfully reproduced the observed response in net assimilation and transpiration rates.     

Untersuchungen zur natürlichen Verjüngung der Buche (Fagus silvatica)

Zusammenfassung Die Untersuchung des Reifevorgangs bei Buchenfrüchten durch Verfolgung von Frischgewicht, Trockengewicht und Fettgehalt ergibt, da? der Reifeproze? erst Anfang bis Ende August beginnt und sechs bis acht Wochen dauert. Eine Beurteilung der Bucheckern auf Keimf?higkeit ist daher frühestens Mitte September m?glich. Auf Standorten mit Auflage von Moder oder Rohhumus wird die Entwicklung der Keimlinge durch eine Bodenbearbeitung nach dem Samenfall wesentlich gef?rdert; bew?hrt hat sich die Scheibenegge Rome TAH 14/28 und der Scheibenpflug TTS. Die schlechtere Keimlingsentwicklung bei fehlender Bodenbearbeitung wird auf eine Sch?digung der Keimpflanze beim Wurzelkontakt mit der obersten stark versauerten Mineralbodenschicht zurückgeführt. Zur F?rderung des Buchenaufschlags hat sich eine Düngung kurz vor oder nach dem Buchenaufschlag nicht bew?hrt; empfehlenswert scheinen dagegen Kalkungen 10 bis 30 Jahre vor Bestandesverjüngung.

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Investigations regarding the natural regeneration of beech (Fagus silvatica)

Summary The ripening process of beech seeds as followed by the measurement of fresh weight, dry weight and fat content starts beginning to end of August and takes 6 to 8 weeks. A judgement of the germination ability is possible not earlier than mid of September. At sites with mor or raw humus the development of the seedlings can be improved substantially by soil cultivation. The unsatisfactory development of seedlings if soil cultivation is missing is caused by a damage of the seedling after beeing in root contact with the uppermost strongly acid mineral soil layer. A fertilization shortly before or after the seed fall has no positive effect on the development of seedlings; liming should be done 10 to 30 years before regeneration of the stand.

     

Die Hymenopteren und Dipterenfauna in Pflanzungen dep Ölhaltigen Rose (Rosa damascena Mill.) in Bulagarien

Zusammenfassung Im Rahmen der z?nologischen Untersuchungen in den Pflanzungen derRosa damascena Mill. in Bulgarien wurden 128 Hymenopteren- und 64 Dipteren-Arten erfa?t. Nach der Ern?hrungsweise wurden die festgestelltenHymenoptera-Arten m sch?dliche, parasi?re, Pr?datoren und indifferente eingeteilt. Die sch?dlichen Arten wie auch 54 Arten Parasiten wurden auch unter Laborbedingungen bis zum Imago gezü chtet. Die T?tigkeit der Pr?datoren wurde durch unmittelbare Beobachtungen im Freien erfa?t. (Syrphidenarten wurden ebenfalls im Labor bis zum Imago gezüchtet). Die sch?dlichen Hymenopteren-Arten lassen sich in Abh?ngigkeit von ihrem trophischen Zusammenhang mit derRosa damascena Mill. in spezifische, st?ndige und zuf?llige Sch?dlinge (Nikolova, 1968) einteilen. Die Aphiden-Arten wurden den indifferenten Arten zugeordnet, weil die ?lhaltige Rose nicht zur Gewinnung der Früchte, sondern der Blüten angebaut wird. Trotzdem wird jedoch ihr Best?uberwert nicht untersch?tzt. Die Ergebnisse werden von z?nologischem. Aspekt diskutiert. Für die Bestimmung der Hymenoptera- und Dipteraarten m?chte ichJ, Pádr, J. Sédivy, M. Čapek, Z. Boucek, L. Masner, I. Ćepelak, M. Slamečkova, K. Samšiňák (Tschechoslovakische sozialistische Republik),A. Jelochovtsev, N. Talenge (UdSSR) undF. Mihályi (Ungarn) meinen Dank aussprechen.     

Radon—Ein neuer analytischer Ansatz zur “In-situ-Bestimmung” der Gasleitf?higkeit von B?den

Vorliegende Arbeit beschreibt ein neuartiges Verfahren zur “In-situ-Bestimmung” der Gasleitf?higkeit von B?den. Es bedient sich des natürlich vorkommenden, radioaktiven Edelgases Radon. Hierbei wird in einer Me?kammer, die auf dem Boden aufsitzt, die H?he der Radonexhalation registriert. Sie ist u. a. direkt von der Gasleitf?higkeit des Bodens abh?ngig. Da das Verfahren zerst?rungsfrei arbeitet. er?ffnen sich eine Vielzahl von Applikationsm?glichkeiten, wie z. B. Beobachtungen befahrungsbedingter Strukturver?nderungen w?hrend und nach Holzerntema?nahmen sowie Untersuchungen zur Regeneration strukturell ver?nderter B?den. Dies kann beliebig oft und zu beliebigen Zeitpunkten am identischen Bodenausschnitt geschehen. The paper describes a new analytical tool for the “in situ” measurement of the gas permeability of soils. It uses on the exhalation of the redioactive rare gas radon. A chamber covering a certain surface area on the ground registers the amount of radon exhald. One of the factors, which directly controls the exhalation rate is the gas permeability. As this is a non-destructive method several possibilities for applications arise, as for example observation and analysis of changes in soil structure during and after regular timber harvesting, i.e. such caused by forest machines, as well as investigations about the regeneration of damaged sites. These investigations can be repeated as often as desired, at any time and, moreover, on the identical spot.     

银叶金合欢组织培养技术

为建立银叶金合欢（Acacia podalyriifolia）组培快繁技术体系,本文对其外植体类型的选择与灭菌处理方法以及不定芽诱导、增殖和生根培养基进行了优化筛选。结果表明,组培最适外植体为半木质化枝条上部;灭菌处理方式以75%酒精（10 s）＋0.1%升汞（5 min）为宜,其污染率为38.67%,诱导率达54.33%;最适宜诱导培养基为MS+6-BA 0.5 mg?L-1+ IBA 0.01 mg?L-1 + GA3 0.3 mg?L-1,诱导率为64%;最佳增殖培养基为MS+6-BA 0.6 mg?L-1+ IBA 0.05 mg?L-1+ GA3 0.1 mg?L-1,增殖系数为3.44;最佳生根培养基为l/4 MS+NAA 0.2 mg?L-1+ IBA 0.8 mg?L-1,生根率为67.1%;移栽基质为黄心土+沙（V黄心土：V沙=2:1）,移栽成活率可达85%以上。