Pathogene Mikroorganismen als Begleiter und Mortalitätsfaktoren des SchwammspinnersLymantria dispar L. und des amerikanischen WebebärenHyphantria cunea Drury

Ohne Zusammenfassung     

Die Nahrungswahl und das Auftreten der Pflanzenschädlinge

Ohne Zusammenfassung     

Dothistroma pini—Eine Gefahr fürPinus sylvestris?

Zusammenfassung Dothistroma pini wurde auf einer ganzen Reihe von Kiefernarten festgestellt. Sporenl?nge und das gelegentliche Auftreten der HauptfruchtformScirrhia pini belegen das Vorhandensein der var.linearis. Konidien wurden von M?rz bis in den November gefunden, besonders zahlreich von April bis Juni. Erstmals, festgestellt wurde das Pathogen aufPinus cembra, P. aristata, P. koraiensis undP. tabuliformis, allerdings ist anzunehmen, da? die Infektion dieser Arten nur unter starkem Infektionsdruck stattfindet und die wirtschaftliche Bedeutung des Pilzes in diesen F?llen sehr begrenzt ist. Gleiches gilt offensichtlich auch fürPinus sylvestris. Diese Kiefernart wird nach unseren Beobachtungen auch bei engem Kontakt mit sehr stark infizierten Schwarzkiefern nur unbedeutend oder überhaupt nicht befallen. In diese Richtung deuten auch die ersten Ergebnisse eines Infektionsversuches, bei demP. sylvestris symptomfrei blieb, w?hrendP. nigra z. T. sehr starke Symptome einer Infektion zeigte. Eine nennenswerte Sch?digung vonP. sylvestris konnte bei Freilandbeobachtungen in keinem Falle festgestellt werden. Gegenteilige Hinweise in der Literatur sind auf Verwechselungen (des Pathogens oder des Wirtes) zurückzuführen.

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Dothistroma pini—a danger for Pinus sylvestris?

Summary Dothistroma pini was found on several different pine species. The length of the conidia and the existence of the teleomorph, which sometimes could be noticed, prove the presence of the var.linearis of the fungus. Conidia were detected between March and November, in high quantities especially from April to June. For the first time, the pathogen has been mentioned onPinus cembra, P. aristata, P. koraiensis andP. tabuliformis. It must be assumed, however, that these species only become infected under high infection pressure. That means, that the economic importance of the pathogen is very limited in these cases. Obviously the same is true withPinus sylvestris. After our observations this pine species was little or not at all infested even when in direct contact with heavily attackedP. nigra-plantations. The result of an infection experiment, in whichP. sylvestris did not show any symptoms whereasP. nigra was partly heavily attacked, points in the same direction. Damages toPinus sylvestris worth mentioning could not be found during observations in the field. Opposite indications from the literature can be explained by mistaking pathogens or host species.

     

Antimicrobial activity of Chenopodium botrys essential oil

Essential oil, isolated by hydrodistillation from Chenopodium botrys aerial parts, expressed significant bactericidal and fungicidal activity against selected strains of microorganisms.     

Free radical scavenging activity of Achillea alexandri-regis extracts

The antioxidative potential of Achillea alexandri-regis has been studied by measuring the influence of herb extracts on hydroxyl and superoxide radicals' quantity in different in vitro systems. The ethyl acetate extract exhibited hydroxyl radical scavenging activity in all tested biological system (liver homogenate, hemolyzed blood, serum and postmitochondrial liver fraction), whereas butanol extract reduced hydroxyl radicals significantly only in the postmitochondrial liver fraction. Both extracts showed superoxide radical scavenging effect only in hemolyzed blood.     

Influence of cytokinins on in vitro morphogenesis in root cultures of Centaurium erythraea—Valuable medicinal plant

The purpose of this work was to acquire more information on the capacity of in vitro grown Centaurium erythraea Gillib. normal and hairy root cultures to simultaneously regenerate adventitious buds and to evaluate the variations induced on regeneration response by treatments with six cytokinins. Explants from normal and hairy root cultures were cultured on half-strength MS medium (1/2 MS) with kinetin (KIN), N⁶-benzylaminopurine (BA), 6-γ,γ-dimethylallylaminopurine (2IP), N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU), 1-Phenyl-3-(1,2,3-thiadiazol-5-yl)urea (TDZ) and 6-[4-Hydroxy-3-methyl-but-2-enylamino]purine (ZEA), used alone in six different concentrations. The average number of adventitious buds per explant was promoted by all of cytokinin treatments. Urea-type cytokinins, TDZ and CPPU were more effective for the induction the morphogenesis of adventitious buds than adenine-type cytokinins. We found that the 1.0 μM CPPU induced the largest number (25.6, 18.2, respectively) of adventitious buds in normal and hairy root culture. TDZ-supplemented media induced highest number of adventitious buds (24.2) from normal root explant, but from hairy root explant average number of buds is lower (20.5). Regenerated shoots were excised and placed on 1/2 MS medium without hormone. The rooted plantlets were successfully acclimatized in greenhouse conditions.     

Editorial

Skadar Lake, a large, shallow, subtropical lake on the Albanian frontier in south-western Yugoslavia, supports a commercial fishery which annually yields nearly a thousand metric tons. Examination of catch statistics plus documentation of increasing effort during 1947 through 1973 reveals a declining catch per unit of effort. Water quality has not changed since 1952. However, changes in gear, effort, and exploitation have apparently caused major shifts in species composition and size of the catch. Rapid technological changes in gear coupled with potential environmental degradation may lead to decreased stocks and over-exploitation. Only by instituting a comprehensive management programme, within the context of international cooperation and sound ecological information, can a high sustained yield be maintained and over-exploitation of commercially important fish stocks in Skadar Lake be presented.     

Eighty-year review of the evolution of landscape ecology: from a spatial planning perspective

Landscape Ecology - Sustainable spatial development requires the establishment of a balance between rational land use and the protection of nature, ecosystems and biodiversity on various spatial...