ÜBER DIE URSACHEN DER UNTERSCHIEDLICHEN RESISTENZ VON VICIA FABA L. GEGENÜBER DER BOHNENBLATTLAUS,APHIS (DORALIS) FABAE SCOP

Zusammenfassung Fruchtbarkeit und Wachstum von vier auf Ackerbohnen (Vicia faba) lebenden Aphiden-Arten (Aphis fabae, A. craccivora, Acyrthosiphon pisum, Megoura viciae) werden von den Sorten Schlanstedter und Rastatter in gegensätzlicher Weise gefördert bzw. gehemmt. Post-infektionelle Resistenzeffekte treten daher einerseits bei Rastatter gegen A. fabae, andererseits aber bei Schlanstedter Ackerbohnen gegen Erbsen- und Wickenläuse auf, während sich A. craccivora auf beiden etwa gleich gut entwickelt.

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Summary Aphis fabae, Aphis craccivora, Acyrthosiphon pisum, and Megoura vicae (abbreviated Af, Ac, Ap and Mv, respectively) were allowed to develop under similar uncaged conditions on Rastatter (R) and Schlanstedter (S) field beans. Large, sometimes contradictory, differences in the fecundities and weights attained by adult apterous virginoparae on these plants were recoreded and ascribed to postinfestation resistance effects.Ap, which feed only on leaves, and Mv, which feed exclusively on internodes, weigh significantly more (17–18%) on R than on S. In contrast, Af, which feed on various plant parts, are 61% heavier on the leaves and 33% heavier on the stems of S than on the corresponding parts of R.However, Ac, which have a distribution on the plants similar to that of Af, are somewhat heavier (12%) on R-leaves and on S-stems than on the corresponding plant parts of the other variety. Such differences are greatly diminished if the aphids are reared on excised leaves and stems immersed in water. In this case growth of the aphids on excised parts of the resistant varieties (on which they previously grew poorly) closely approaches that on the intact satisfactory varieties (on which they grew well). Only small (Af, Ac) or no (Ap, Mv) improvement in growth results when the aphids are reared on excised parts of the satisfactory variety. Thus, the weights of apterous adults of Ap on excised S-leaves were only 17% greater than on intact S-leaves, whereas they were similar on excised and intact R-leaves. For Af, adult weights were 81% greater on excised R-leaves, 51% greater on excised S-leaves, and only 19% or no greater on excised R- and S-stems, respectively, than those on the corresponding intact plant parts.The possibility is discussed that these contradictory effects result from a mobilization and increase of proteinaceous constituents in the excised plant parts. Whereas the nutrition and growth of aphids on the resistant variety may thus become optimal, such an increase above an already optimal nutrient level on the satisfactory variety would not increase growth beyond the limit already achieved by a species. It is further deduced that postinfestational resistance to aphids of field beans depends on the nutrient value of the sap available to the aphids. However, since the nutritional demands of different aphid species may also differ, it is unlikely that a single plant species will be resistant to aphids in general.

     

ÜBER DIE URSACHEN DER UNTERSCHIEDLICHEN RESISTENZ VON VICIA FABA L. GEGENÜBER DER BOHNENBLATTLAUS APHIS (DORALIS) FABAE SCOP.*

Zusammenfassung Unter der Voraussetzung, daß die Größe ungeflügelter virginoparer Bohnenläuse, Aphis fabae Scop., ein besser geeigneter Parameter für antibiotische Wirkungen ihrer Wirtspflanzen sein dürfte als ihre Tochterproduktion oder Lebensdauer, werden die Faktoren untersucht, welche das larvale Wachstum beeinflussen könnten. Die Größe der Imagines sowie Umfang und Sequenz ihrer Nachkommenproduktion stehen in enger Beziehung zu den Ernährungsverhältnissen, unter denen die Mütter während ihrer Larval- und Imaginalphase leben. Die Entwicklungsgeschwindigkeit nimmt von 5° bis 30° — immer langsamer — zu, das Wachstum aber nur bis 14°; höhere Temperaturen ergeben zunehmend wieder kleinere Imagines. Die Imaginalgröße, die von Läusen auf ausgestanzten Blattscheiben erreicht wird, vermindert sich mit sinkendem Durchmesser bzw. bei ansteigender Populationsdichte. Auf wachsenden Blättern (in situ) entstehen um so größere Imagines, je größer der prozentuale Zuwachs der Blattfläche während der Postembryonalentwicklung ist. Abschneiden und Bewurzeln von Primärblättern beeinflussen die Größe der auf ihnen aufgezogenen Bohnenläuse bei der Ackerbohnensorte Schlanstedter fast nicht, während sie auf Rastatter größere bzw. wieder so kleine Adulte ergeben wie an intakten Pflanzen. Als Ursache aller dieser Wachstumsreaktionen der Bohnenläuse wird die Wüchsigkeit, speziell die Höhe des Aminosäurespiegels im Substrat, angesehen. Die ökologischen Folgen für den Wirtswechsel und die Resistenzerscheinungen werden diskutiert.

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Summary Using the adult size (length, weight, frontal projection of surface) of young virginoparous bean aphids as a parameter for antibiotic effects of the host plant, detailed knowledge is wanted of postembryonic growth reactions of the aphids to different environmental factors.On the same food material daughters of small mothers grow bigger, those of big ones smaller than their mothers, but they still differ significantly from each other. Direction and scope of the size modification between two generations depend on the nutritional difference of the substratum on which mothers and daughters develop.On a substratum of high value and with 20°, big mothers produce nearly two-thirds of their total offspring during the first week and another third in the second week, while the small ones begin only with a quarter. But then they recover with 40% in the second and a quarter in the third week and so they finally reach 84% of the total production of big mothers, though with a retardation of one week. Also the quantitative proportions of embryogenesis during pro- and postmetamorphic development and therefore the sequence of births are results of the nutritional situation during the larval and imaginal stages, respectively, of the virginoparae.Whereas with rising temperature the developmental speed increases in the usual manner —with the minimum at 5° and the maximum not much above 30° —, growth is already optimal at 14–15° and decreases promptly with temperatures above the optimum. Obviously with temperatures too high or too low the surplus of high energy material (amino acids) necessary for growth processes is consumed by the maintenance metabolism or blocked under these conditions. Aphis fabae-virginoparae grown on leaf discs floating upside down on tap water develop into smaller adults as diameters (22–16–10.5 mm) decrease or population density (2, 6 or 20 larvae on 200 mm² leaf disc each) increases (differences significant at the 0,1% level). While on leaves in situ such differences do not prove significant, young virginoparae grow the bigger, the more the leaf area increased relatively during their larval development. Therefore the differences in the antibiotic aphid resistance of young Rastatt and Schlanstedt field bean plants of the same age may be reduced to a difference in phase of the growth of their leaves.On leaf discs of different age the biggest adults develop on discs from mature assimilating foliage, which after isolation may evidently mobilize more protein reserves than younger or older ones, probably as the young leaf itself yet depends on an influx of amino acids, and the old leaf already is more or less exhausted of them.Bean aphids developing on normal intact, detached, or detached and re-rooted primary leaves of the susceptible field bean Schlanstedter show nearly no significant differences in adult size, but on corresponding leaves of the resistant Rastatter they react with increased and decreased growth respectively (in comparison with their normal diminished size). The Schlanstedt field beans provide an uniform and equivalent feeding basis for the growth of black bean aphids during nearly all stages of their physiological development. They represent a main host (host of class I in the sense of Mosbacher). The Rastatt field beans on the other hand are secondary hosts (hosts of class II), which guarantee a sufficient promotion of aphid growth (in the sense of Kennedy et al.) only in stages of an increased mobility of soluble protein elements in growing or senescent organs.

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Quedlinburger Beiträge zur Züchtungsforschung Nr. 72.

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DIE WIRKUNG VON PHYTOHORMONEN AUF KEIMUNG UND ENTWICKLUNG VON FARNPROTHALLIEN IV. DIE WIRKUNG VON UNTERSCHIEDLICHEN GIBBERELLINE UND VON ALLO-GIBBERINSAURE AUF DIE AUSLOSUNG DER ANTHERIDIENBILDUNG BEI ANEMIA PHYLLITIDIS L. UND EINIGEN POLYPODIACEEN

The relative activities of seven gibberellins have been testedin their ability to induce antheridia in prothallia of Anemiaphyllitidis. The spectrum of activities differs from the spectradescribed for other gibberellin reactions. Allogibberic acidproved to be highly active in the Anemia test. Additionallyit causes a change in the polarity of the germinating spore.Under the influence of this compound the primary rhizoid istransformed into an additional chloronema. In high concentrationsof allogibberic acid more than 80% of the prothallia developinto those "twins". Out of the polypodiaceous ferns only fewspecies respond to gibberellin application. The relations between chemical structure and activity of differentgibberellins are discussed. (Received January 17, 1966; )     

DIE WIRKUNG KOMBINIERTER ANWENDUNG INSEKTIZIDER PHOSPHORSÄUREESTER UND CARBAMATE AUF DROSOPHILA MELANOGASTER1

Zusammenfassung Die Kontaktwirkung von Phosphorestern, Carbamaten und Kombinationen beider Wirkstoffgruppen auf Drosophila melanogaster wurde untersucht.Auf Grund bestimmter Merkmale der Zeit-Wirkungskurven lassen sich drei verschiedene Typen von Phosphorestern unterscheiden.In Kombination mit subletalen Dosen des reversibel wirkenden Carbamats Isolan werden die Wirkungen der Phosphorester in unterschiedlicher Weise verändert.Die möglichen Ursachen für diese Wirkungsunterschiede und Wirkungsveräderungen werden diskutiert.

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Summary Sixteen organic phosphorus insecticides and three insecticidal carbamates were tested per se and in combinations against Drosophila melanogaster.Sublethal doses of the carbamate at first accelerated the effect of parathion, paraoxon, chlorthion, malathion, DDVP, trichlorphon, phosphamidon, and mevinphos (type 1). However, later on the time-response curves indicated retardation of mortality and even recovery of the poisoned flies. Similar results were obtained in combinations with guthion, endothion, G 24747, G 24746, diazinon, and diazoxon (type 2), a group of phosphorus esters the timeresponse curves of which under our conditions are not sigmoidal like type 1, but broken and partly showing a tendency to recovery of the flies.The recovery phenomenon in combinations occurred only when the phosphorus ester uptake by the flies was stopped after a fixed time; thus supplies were cut off, degrading systems could inactivate free phosphorus ester and acetylcholinesterase regenerated from carbamate-blockage was not inhibited anew.The typical sigmoidal time-response curves of EPN and thiometon (type 3) were not altered by combination with carbamates; that may indicate absence of effective enzymes for degrading these compounds.

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Kurzfassung der gleichnamigen Dissertation der landwirtschaftlichen Fakultät.     

ÜBER DEN SITZ DER CO2-REZEPTOREN BEI DER LARVE VON OTIORRHYNCHUS SULCATUS

Zusammenfassung Mit Hilfe bilateraler Exstirpation der Kopfanhänge der Larve von O. sulcatus wurde der Sitz der Chemorezeptoren lokalisiert, welche bei der Orientierung im CO₂-Gradienten beteiligt sind. Diese CO₂-Rezeptoren liegen hauptsächlich auf den Endgliedern der Maxillarpalpen, wahrscheinlich auf deren Spitze. Fühler und Labialpalpen sind an der Orientierung nur in sehr geringem Masse beteiligt, die letzteren möglicherweise gar nicht.Unilaterale Exstirpation aller drei Kopfanhänge führte zu Wendungen nach der intakten Seite hin, häufig auch zu ganzen Kreisbewegungen. Der gleiche Effekt wurde durch unilaterale Entfernung eines einzelnen Maxillarpalpus erzielt.Die Orientierungsversuche erfolgten in CO₂-Gradienten mit bekanntem Verlauf (Abb. 2).

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Summary By means of bilateral amputation of the head appendages the chemoreceptors involved in the orientation to a CO₂-gradient were located. These CO₂-receptors are mainly situated on the terminal joints of the maxillary palpi, presumably on their apex. Antennae and labial palpi are of little importance, the latter possibly of none at all. Unilateral amputation of all three head appendages caused the larvae to turn to the intact side and to perform circus movements. The same effect was obtained if only a single maxillary palpus was removed.The orientation experiments were carried out in measured CO₂-gradients (Fig. 2).