Chemisch-mineralogische und mikromorphologische untersuchung einer eutrophen (Ramann-) braunerde des Budapester Hügellandes

In spite of the fact that Ramann's concept of Braunerde was extensively used throughout the world, some pedogenic processes and soil properties which are important for the formation and existence of Brown Forest Soils (eutrophic brown earths) are still not well known. Hence, a soil was investigated which was classified as a “Braunerde” by Ramann in 1909. The main question was, whether there might be soil constituents such as inorganic amorphous substances (allophanes) which are able to stabilize the brown-earth fabric, or to inhibit clay migration. From chemical data as well as from the magnitude of the pH-dependent CEC, it was deduced that there are no appreciable amounts of allophanes within the soil. The fabric, however, seems to be stabilized by colloid-chemical flocculation of the clay particles caused by large amounts of carbonates and silicates deposited with the parent material (loess). The decalcified solum is still rich in silicates, especially sand and coarse-silt-sized micas and feldspars (60–200 and 20–60 μm fractions, respectively). Since - in comparison - loesses and loess-derived soils of the Central German mountain region contain less silicates, mainly in fine and medium silt fractions (2–6 and 6–20 μm diameter, respectively), the coarser-grained silicates were assumed to be important for maintaining the Ca²⁺ and Mg²⁺ saturation of the soil by continuous weathering and thus stabilizing the brown-earth fabric.Although the soil is saturated predominantly with Ca²⁺ and Mg²⁺ ions, clay migration proceeds within the upper horizons. This was shown by calculation of the amounts of clay formed by breakdown of micas originally present in the parent material (“clay formation balance”), as well as by micromorphological studies. Furthermore, micromorphological studies and x-ray diffraction data gave some evidence for the migration of preferably finest grained montmorillonitic clays (smectites) penetrated by organic substances (humus). This kind of “selective clay migration” was assumed to be caused by high Ca²⁺ (or Mg²⁺) concentrations in soil solution required for flocculation of humus-penetrated (humus-coated) smectites. From the occurrence of these “humus-smectites” the possibility was assumed that the soil studied has been developed from a former Chernozem type.Quantitatively, clay migration does not reach the amounts of clay formation (breakdown of micas) accompanied by precipitation of iron oxides on mineral surfaces (“Verbraunung”). Thus, the soil profile visually and macromorphologically clearly exhibits the features of brown earths. On the other hand, however, some clay migration was observed. Hence, the soil was classified as a “brown earth with some clay migration” (“schwach durchschlämmte Braunerde”).Judging from the results of the “clay formation balance” an appreciable pedogenic (autigenic) clay formation from weathering products of feldspars was excluded for the soil studied.     

Inhibition of potato sprout growth by carvone enantiomers and their bioconversion in sprouts

Summary The monoterpenes (R)-(−)-carvone and (S)-(+)-carvone inhibited sprout growth in a model system consisting of sprouts growing from potato eye pieces. The sprout tissue was not necrotic after carvone treatment and the inhibition was reversible, since after treatment the sprouts showed regrowth either by continued top growth or by branching. However, the effect of both isomers on sprout growth differed, and (S)-(+)-carvone inhibited the elongation of the sprouts sooner than did (R)-(−)-carvone. This might be explained by a faster uptake of the former, since the concentration of (S)-(+)-carvone and its derivatives was twice as high during the first 4 days compared with (R)-(−)-carvone-treated sprouts. The sprouts were able to reduce (R)-(−)-carvone mainly into neodihydrocarveol, and (S)-(+)-carvone into neoisodihydrocarveol; in addition hydroxylated compounds were also detected. To whom correspondence should be addressed     

Control of Dutch elm disease by the sterol biosynthesis inhibitors fenpropimorph and fenpropidin

Sterol biosynthesis inhibitors that inhibit the yeast-hyphae conversion inOphiostoma ulmi suppressed Dutch elm disease development in two elm clones. After curative treatment with fenpropimorph-sulphate of 27 Vegeta elms which had previously been inoculated withO. ulmi, 25 trees did not show disease symptoms by the end of the second season. All 41 control trees, inoculated withO. ulmi only, were clearly diseased. In an experiment with Commelin elms three fenpropimorph salts and thiabendazole were compared. Injection of the trees three weeks after inoculation withO. ulmi gave by the end of the second season no symptoms of Dutch elm disease in any of the trees injected with fenpropimorph-phosphate or thiabendazole, and in most trees injected with fenpropimorph-acetate or-sulphate. Similar treatments with the free base of fenpropimorph and fenpropidin-sulphate were less effective due to insufficient uptake of the fenpropimorph emulsion and phytotoxicity of fenpropidin-sulphate, respectively. Injection of fenpropimorph-sulphate or thiabendazole six weeks after inoculation withO. ulmi did not result in significant differences from the control group inoculated withO. ulmi only.Fenpropimorph-phosphate and-sulphate completely suppressed Dutch elm disease upon injection of only 7.5 or 10 g per tree (average tree diameter 28 cm). Residue analyses showed only a slow decrease in concentration of the fungicide over two growing seasons and an apparent transport into the new annual ring, other prerequisites for a possible future use for control of Dutch elm disease.Samenvatting De iepeziekte kan onderdrukt worden door sterolbiosyntheseremmers die de overgang vanOphiostoma ulmi van de gistvorm in de hyfevorm remmen. Aan het eind van het tweede seizoen na een curatieve behandeling van 27 Vegeta iepen met fenpropimorfsulfaat bleken 25 bomen geen symptomen van iepeziekte te vertonen. Alle controlebomen, die alleen metO. ulmi geïnoculeerd waren, waren duidelijk ziek. In een proef met Commelin iepen werden drie fenpropimorfzouten en thiabendazool vergeleken. De zouten werden drie weken na de inoculatie metO. ulmi geïnjecteerd. Aan het eind van het tweede seizoen vertoonden geen van de bomen die met fenpropimorffosfaat of thiabendazool geïnjecteerd waren en slechts enkele bomen die met fenpropimorfacetaat of-sulfaat geïnjecteerd waren iepeziektesymptomen. Behandelingen met fenpropimorf (vrije base) en fenpropidinsulfaat werkten minder goed door de slechte opname van de fenpropimorfemulsie en de fytotoxiciteit van fenpropidin. Injectie met fenpropimorfsulfaat of thiabendazool zes weken na inoculatie leidde niet tot significante verschillen met de controlegroep die alleen metO. ulmi geïnoculeerd was.Een dosis fenpropimorffosfaat of-sulfaat van 7.5 of 10 g per boom met een gemiddelde boomdiameter van 26 cm bleek de iepeziekte volledig te kunnen onderdrukken. Uit residue-onderzoek bleek dat de concentratie van het fungicide gedurende de twee groeiseizoenen slechts langzaam afnam en dat het middel naar de nieuwe jaarring werd getransporteerd, twee voorwaarden voor een toepassing op praktijkschaal van fenpropimorf voor de bestrijding van de iepeziekte.     

Pseudomonas for biological control of dutch elm disease. I. Labeling,detection and identification of pseudomonas isolates injected into elms; comparison of various methods

To understand the mechanisms involved in biological control of Dutch elm disease byPseudomonas, data were needed on the distribution of the introduced bacteria within elm and on the development of the bacterial population over a period of time.As traditional biochemical identification techniques are not suitable for distinguishment between individualPseudomonas isolates, three alternative approaches were compared.

Pseudomonas for biological control of Dutch elm disease. III. Field trials at various locations in the Netherlands

The prophylactic effect in elm of one treatment with aPseudomonas isolate was monitored in two types of field trials. In one type only natural Dutch elm disease infections were monitored and hence large numbers of trees were necessary due to the low incidence of natural occurring infections. In the other type trees were artificially infected.The large-scale field trials in which only natural infections were monitored, were based on expected annual losses due to Dutch elm disease of approximately 2%. As a result of the Dutch sanitation program, which was based on the prompt removal of every weakened or diseased elm, the actual losses were generally threefold lower. Dutch elm disease incidence was 22–45% lower in the trees treated with aPseudomonas isolate in the year of treatment and the year after. The results of the biocontrol treatment were negatively influenced because on several locations trees were felled that showed initial signs of Dutch elm disease, which probably would have disappeared during the season.The advantage of artificial infections withOphiostoma ulmi was a reproducable development of symptoms and the possibility to maintain diseased trees, at least till the first signs of elm bark beetle breeding. For Commelin elms an increase in symptoms was observed with increasingO. ulmi dose till 3000 conidia per tree; the standard 500 000 conidia used for most experiments was well above this critical value. No decrease in effectiveness of the bacterial pre-treatment was observed with increasingO. ulmi inoculum. Different bacterial treatments suggested that injections at a smaller interval (i.e. more injections per tree) may result in a better prophylactic effect, but the significance of the correlation remained doubtful. A comparison of several elm species and clones showed the importance of the host tree. Prophylaxis as a result of one bacterial treatment was shown repeatedly in Commelin elms; the numbers of trees showing symptoms by the end of the second year were 10 to 85% lower in the bacteria-treated groups in comparison with the controls. Also in one experiment with Belgica elms prophylaxis was observed, resulting in a 84% decrease in the number of trees showing symptoms by the end of the second year after the prophylactic treatment followed by inoculation withO. ulmi. In Vegeta symptom development was only less severe and in field elms (Ulmus carpinifolia) some prophylactic effect was observed in one experiment, but no effect in two others.Samenvatting De mogelijke bescherming tegen de iepeziekte, verkregen door injectie van de boom met bacteriën van het geslachtPseudomonas, werd gemeten in twee soorten experimenten. In het ene soort werden natuurlijke infecties gemeten, waardoor grote proefgroepen nodig waren. In het andere soort werden de iepen kunstmatig geinfecteerd.De grootschalige veldexperimenten waarbij natuurlijke iepeziekte-infecties werden gemeten, waren gebaseerd op een verwachte jaarlijkse uitval van 2%. Als gevolg van de landelijke bestrijdingscampagne bleken de verliezen slechts ongeveer een derde hiervan te zijn. Er kwam minder iepeziekte voor in de metPseudomonas geïnjecteerde bomen in het jaar van injectie en in het jaar daarna. Een storende invloed op de resultaten had het effect dat ook met bacteriën geïnjecteerde bomen soms beginnende symptomen vertonen na infectie metOphiostoma ulmi, symptomen die in de loop van het seizoen soms weer verdwijnen. Als gevolg van de bestrijdingscampagne werden zulke bomen toch geveld.Het voordeel van kunstmatige infecties metO. ulmi was een voorspelbaar verloop van de symptoomontwikkeling en de mogelijkheid om zieke bomen te laten staan tot er iepespintkevers in kwamen. In Commelin iepen bleken de symptomen toe te nemen met een tot 3000 conidiën per boom toenemende dosisO. ulmi. De gebruikelijke 500000 conidiën die in de meeste experimenten werden gebruikt lagen ver boven deze kritische waarde. Er werd geen effect van een toenemende dosisO. ulmi op de effectiviteit van een bacteriebehandeling waargenomen.Uit variaties in de diverse bacteriebehandelingen kwam naar voren dat injecties met een kleinere tussenruimte (dus meer injecties per boom) mogelijk het effect verbeterden, maar de significantie van deze correlatie bleef twijfelachtig.Vergelijken van diverse iepen toont dat soort en kloon type een belangrijke rol speelt bij deze bestrijdingsmethode. Bescherming tegen de iepeziekte als gevolg van een bacteriebehandeling werd diverse malen aangetoond in Commelin iepen; het aantal bomen met iepeziekte-symptomen was aan het eind van het tweede seizoen in de met bacteriën behandelde groepen 10 tot 85 % lager dan in de controlegroepen. Ook in een experiment met Belgica iepen werd een goede bescherming gemeten. In Vegeta werd slechts een verminderde symptoomontwikkeling gemeten en in veldiepen (U. carpinifolia) werd enige bescherming gevonden in één experiment, maar geen effect in twee andere.     

Production in vitro of phytotoxic compounds by non-aggressive and aggressive isolates of Ophiostoma ulmi, the Dutch elm disease pathogen

Development in shake culture of two non-aggressive and two aggressive isolates of the Dutch elm disease fungus, Ophiostoma ulmi, was monitored in a time course study. The time sequences for the production of total biomass, spores, polysaccharides and phytotoxic compounds were followed, but none of them showed a clear correlation with aggressiveness. The same parameters were examined for nine non-aggressive and 11 aggressive isolates after 10 days growth. Of two phytotoxic compounds, a glycopeptide and the protein cerato-ulmin, only the latter was generally produced in larger quantities by aggressive isolates. However, variability in production and a number of exceptions to the trend made cerato-ulmin production an uncertain criterion for assessing the aggressiveness of an individual isolate.Immunofluorescence of sections of infected elms treated with an anti-glycopeptide serum showed intense fluorescence only in the cell walls of the fungus. Apparently the glycopeptide is abundantly present in or on fungal cell walls.The roles of the different compounds in relation to Dutch elm disease symptom development are discussed.     

Über Zucker in grünen Erbsen bei unterschiedlicher Kali- und Phosphorsäureversorgung der Pflanzen

Zusammenfassung In zweijährigen Gefäßversuchen mit sterilem Sand als Bodensubstrat und Kaliumsulfat und Calciumdiphosphat in Differenzdüngung wurden Erbsen Kleine Rheinländerin in drei gleichen Versuchsreihen herangezogen, von denen die erste bei Aufgang der ersten Blüten, die zweite in der Grünreife der Samen und die dritte in der Vollreife geerntet wurden.Im methodischen Teil werden die Vegetationsversuche, die Ernte und die Konservierung des Pflanzenmaterials, die Extraktion der Zucker und die papierchromatographische Analyse erörtert.Die Erträge an Hülsen und Samen zeigen in beiden Versuchsjahren in ihrer Höhe unterschiedliche Tendenzen, die vor allem auf die verschiedenartigen Klimabedingungen im Zusammenwirken mit der Düngung — besonders hoher Kalidüngung — zurückgeführt werden. Quantitativ wurden im Erntematerial des 1. Schnittes und in Stroh und Hülsen der 2. Ernte Saccharose, Glucose und Fructose, in den Samen der 2. Ernte nur Saccharose ermittelt. Zwischen den Gehalten an einzelnen Nährstoffen und den Zuckergehalten in der oberirdischen pflanzlichen Substanz sind keine direkten Beziehungen erkennbar. Lediglich ist eine deutliche Depression der Hexosengehalte bei hoher Kalidüngung sichtbar. Die Mangelverhältnisse wirken sich je nach Alter der Pflanzen unterschiedlich aus, wie auch aus der Literatur zu ersehen ist. Eine düngungsbedingte Reifeverzögerung der Pflanzen zum Zeitpunkt des 2. Schnittes durch höchste P-Gaben wird aus den unterschiedlichen Tendenzen in der Ertragshöhe der einzelnen Erntekomponenten zum 2. und 3. Erntetermin geschlossen. Sie wirkt sich in den Zuckergehalten des Erntematerials kaum aus. Diese Reifeverzögerung und die mögliche Wirkung hoher Kaligaben werden näher erläutert.

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Summary In pot experiments with sterile sand as ground substratum and potassium sulphate and calcium diphosphate in differential fertilising peas were grown in three equal experimental rows, of which the first was harvested at the appearance of the first blossoms, the second when the seed was green ripe and the third at full ripeness.The methodical part discusses the vegetation experiments, the harvesting and preserving of the plant material, extraction of sugar and paper-chromatographic analysis.The yields in pods and seed show in the two experiment years different tendencies in quantity, which can be mainly ascribed to the different climatic conditions combined with fertilisation — especially with heavy potash fertilising. Quantitatively there were traced in the harvested material of the first cut and in straw and pods of the second harvest saccharose, glucose and fructose, in the seed of the second harvest only saccharose. Between the contents in individual nutritives and sugar contents in the above-ground plant substance no direct relations are recognisable. Visible is merely an obvious depression of the hexosen contents when there is heavy potash fertilising. Deficiency conditions appear varyingly, according to the age of the plants, as the literature also shows. A fertilisation-conditioned delay in maturity of the plants at the time of the second cut through maximum P-dosing is deduced from the varying tendencies in the amount of yield of the individual harvest components at the date of the second and third harvest. This has scarcely any effect on the sugar contents of the harvested material. This delay in maturity and the possible effect of heavy doses of potash are discussed in detail.

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Résumé Dans le cadre d'essais en vase clos rempli de sable stérile remplaçant le sol naturel et de sulfate de potassium et de diphosphate de calcium comme engrais différencié, on a cultivé des pois dans une série de trois expériences analogues: la récolte a été effectué pour la première lors de l'éclosion des premières fleurs, pour la deuxième lors de la maturité des graines encore vertes, et pour la troisième lors de la maturité pleine.Dans la partie méthodique, il est question des expériences de développement de la végétation, de la récolte et de la conservation des plantes, de l'extraction des sucres et de l'analyse chromatographique sur bande de papier.Les récoltes des graines et des gousses démontrent, quant à la quantité, dans les deux années sur lesquelles portaient les essais, des résultats différents, dépendant, en particulier, des conditions climatiques différentes, qui sont dues surtout à l'apport d'engrais, et particulièrement à celui élévé de potassium. En considération des quantités, l'analyse de la première coupe et des pailles et des gousses de la deuxième récolte a relevé l'existence de saccharose, de glucose et de fructose, mais dans les graines de la deuxième récolte seulement de la saccharose. On ne peut donc pas établir des rapports directs entre les teneurs en engrais particuliers et les teneurs en sucres de la substance végétale croissant au dessus du sol. La seule chose évidente, c'est la dépression en teneur d'hexoses en cas d'existence élevée d'engrais de potassium. La situation résultant d'un manque quelconque, a une influence bien différente suivant l'âge des plantes ce qui ressort de la littérature connue. Le retardement de la maturité dépendant de l'apport maximum d'engrais de phosphates à la date de la deuxième coupe est déduit des données variant pour les quantités récoltées des différentes parties faisant l'objet de la récolte à la date de la deuxième et troisième récolte. Toutefois, il n'y a guère une influence sur les teneurs en sucres pour les corps végétaux récoltés. Ce retardement de la maturité et l'influence possible des apports en potassium élevés sont étudiés plus exactement par la suite.