Translocation of 14C-glyphosate in johnsongrass (Sorghum halepense L. Pers.) as affected by growth stage and rhizome length

Studies were conducted in the green house on ¹⁴C-methyllabelled glyphosate translocation in johnsongrass as affected by rhizome length and growth stage. The amount of ¹⁴C measured by the liquid scintillation technique in the rhizomes (2-8%) increased with rhizome length (10, 20 or 30 cm) and tended to increase with growth stage (15-30 cm tall, 45-60 cm tall, or at seedhead), but the amount of ¹⁴C per g fresh rhizome weight was almost similar in all cases. Of the total amount applied per plant (0·2 μCi) about 1/3 or less remained on the treated leaf area, while another 1/3 was a absorbed into the treated leaves. Autoradiographs showed that the ¹⁴C label moved to all plant parts, basipetally and acropetally. Migration du glyphosate ¹⁴ C chez le sorgho d'Alep (Sorghum halepense L. Pers.) en relation avec le stage de croissance et la longueur du rhizome Des recherches ont été effectuées en serru sur la migration du glyphosate marqué au ¹⁴C sur le méthyle, chez le sorgho d'Alep, en relation avec la longueur du rhizome et le stade de croissance. La quantité de ¹⁴C mesurée par la technique de scintillation liquide dans les rhizomes (2 à 8%) s'est accrue avec la longueur du rhizome (10, 20 ou 30 cm) et elle a eu tendance à augmenter avec le stade de croissance (Hauteur 15-30 cm, hauteur 45-60 cm ou épiaison), mais la quantité de ¹⁴C par gramme de poids frais de rhizome est restée Presque identique dans tous les cas. Environ 1/3, ou moins, de la quantitéà la surface des feuilles traitées par plante (0,2 μCi), est restéà la surface des feuilles traitées cependant qu'un autre 1/3 a été absorbé dans less feuilles traitées Les autoradiographies ont montré que le ¹⁴C marqueur a migré dans toutes les parties de la plante, dans le sens basipète et dans le sens acropète. Translokation von ¹⁴C-Glyphosat in Johnsongras (Sorghum halepense L. Pers.) in Abhängigkeit vom Wachstumsstadium der Pflanzen und der Rhizomlänge Im Gewächshaus wurden Versuche über die Translokation von ¹⁴C-Glyphosat in Johnsongras (Sorghum halepense L. Pers.) in Abhängigkeit vom Wachstumsstadium der Pflanzen und der Rhizomlänge durchgeführt. An den Rhizomen stieg der Gehalt von ¹⁴C(2–8%), gemessen mit der Flüssig-Szintillationstechnik, mit zunehmender Rhizomlänge (10, 20 oder 30 cm) an und nahm tendenziell auch mit fortschreitendem Pflanzenwachstum zu (15–30 cm und 45–60 cm Sprosslänge oder nach dem Rispenschieben); jedoch blieb die Menge pro g Rhizomfrischgewicht beinahe konstant. Von der insgesamt ausgebrachten Menge pro Pflanze (0.2 μCi) blieben bis zu 1/3 auf der behandelten Blättern absorbiert wurde. Die Autoradiographie zeigte, dass der ¹⁴C markierte Teil in alle Pflanzenteile sowohl basipetal wie auch akropetal transportiert wurde.     

Absorption and translocation of 14C fosamine by three woody plant species

Absorption and translocation of ¹⁴C fosamine (ethyl hydrogen (aminocarbonyl) phosphonate) and/or fosamine metabolites were monitored in intermediately susceptible seedling black cherry (Prunus serotina Ehrh.) and resistant seedling rhododendron (Rhododendron sp.) and magnolia (Magnolia sp.). The mid two-thirds of the third leaf below the apical bud of each plant was treated with 0·5 μCi ¹⁴C fosamine (carbonyl carbon labelled). Plants were harvested 3, 7 and 14 days following treatment. In black cherry the majority of ¹⁴C absorption and translocation occurred during the second week following treatment, while magnolia and rhododendron translocated and absorbed most of the ¹⁴C within 3 days after treatment. Retention of ¹⁴C in the treated portion of the treated leaf did not differ between species. However, total translocated ¹⁴C was greatest in black cherry, less in magnolia, und minimal in rhododendron. Magnolia translocated ¹⁴C basipetally, while black cherry translocated acropetally, as well as basipetally. Absorpiion et migration de la fosamine ¹⁴C chez trois espèces de plantes ligneuses L'absorptlon et la migration de La ¹⁴C fosamine ((amino carbonyl) phosphonate d'éthyle hydrogène) et/ou de ses métabolites, ont étéétudiées chez des plantules moyennement sensibles de Prunus serotina (Ehrh.) et chez des plantules résistantes de rhododendron (Rhododendron sp.) et de magnolia (Magnolia sp). Les deux tiers moyens de la troisième feuille en-dessous du bourgeon apical de chaque plant ont été traités avec 0.5 Ci ¹⁴C de fosamine (marquée sur le carbone du carbonyl). Les plantes ont été récoltées 3, 7 et 14 jours après le traitement. Chez P. serotina, la plus grande partie de l'absorption et de la migration du ¹⁴C a eu lieu durant la deuxième semaine après le traitement, alors que chez le magnolia et le rhododendron, le maximum d'adsorption et de migration s'est situé dans les trois jours qui ont suivi le traitement. La rétention du ¹⁴C dans la partie traitée n'a pas variè d'une espèce à l'autre. Toutefois, la quantité totale de ¹⁴C qui a migré a été plus grande chez P. serotina, moindre chez le magnolia et minimaie chez le rhododendron. Chez le magnolia, la migration du ¹⁴C s'opere dans le sens basipète, alors que chez le P. serotina. elle s'effectue aussi bien dans le sens acropète que dans le sens basipète. Aufnahme- und Trunstokaiion von ¹⁴C-Fosaminc bei drei Gehölzpflanzen Es wurde die Aufnahme und die Translokation von ¹⁴C Fosamine (O-Äthyl-aminocarbonylphosphonsäure) und/oder seiner Abbauprodukte bei drei Gehölzarten beobachtet. Verwendet wurden Sämlinge der Traubenkirsche (Prunus serotina Ehrh.), die eine mittlere Empfindlichkeit zeigt und Sämlinge des resistenten Rhododendron (Rhododendron sp.) und der ebenfalls resistenten Magnolie (Magnolia sp.). Die mittleren zwei Drittel des dritten Blattes unterhalb der Endknospe wurden bei jeder Pflanze mit 0.5 μCi ¹⁴C-Fosamine (markiert am Carbonylkohlenstoff) behandelt. Die Pflanzen wurden nach 3, 7 und 14 Tagen nach der Behandlung geerntet. Bei der Traubenkirsche wurde während der zweiten Woche am meisten ¹⁴C aufgenommen und transloziert, während dies bei der Magnolie und dem Rhododendron bereits innerhalb der ersten drei Tage der Fall war. Bezüglich der Retention von ¹⁴C in der behandelten Blattfläche unterschieden sich die drei Arten nicht. In der Traubenkirsche wurde aber am meisten ¹⁴C transloziert, weniger in der Magnolie und am wenigsten im Rhododendron. Die Magnolie translozierte das ¹⁴C basipetal, während die Traubenkirsche akropetal wie basipetal translozierte.     

Effect of canopy cover,seeding depth,and soil moisture on emergence of Centaurea maculosa and C. diffusa*

The effects of canopy cover, seeding depth, and soil moisture on emergence of Centaurea maculosa Lam. and C. diffusa Lam. were studied. Canopy cover had no effect on ermergence rate (seedlings/day/100 seeds) of either species. Seeds of both species emerged faster when placed on the soil surface. Emergence rate decreased as seeding depth increased. Both species required more than 55% initial soil moisture to initiate emergence, with 65–70% being optimum. Percentage emergence followed exactly the same trend as emergence rate. C. maculosa had better emergence characteristics over a wider range of conditions than C. diffusa, possibly being some of the reasons for the former having a wider geographical distribution in the United States and Canada.     

Metabolic fate of [14C]endrin in bluegill fish

Bluegill absorbed 85% of 1 ppb of endrin from water within 48 hr under static exposure conditions. The absorbed radiocarbon was eliminated linearly with a half-life of about 4 weeks. Analyses of eliminated radioactivity revealed only conjugated metabolites. 12-anti-Hydroxyendrin and 12-syn-hydroxyendrin were tentatively identified by cochromatography using thin-layer chromatography/autoradiography and gas chromatography. These metabolites were also present as conjugates in the fish organs. Seventy-three percent of the absorbed radioactivity recovered from fish extracts was in the form of unchanged endrin.     

Comparative inhibition of the juvenile hormone esterases from Trichoplusia ni,Tenebrio molitor, and Musca domestica

Twenty-seven compounds were screened as potential inhibitors of juvenile hormone esterases. Of these compounds O-ethyl-S-phenyl phosphoramidothiolate provided the best inhibition for the cabbage looper, Trichoplusia ni (Hubner), and the yellow mealworm, Tenebrio molitor L., while the juvenile hormone esterases of the house fly, Musca domestica L., were best inhibited by a juvenoid carbamate (1-(m-phenoxy-N-ethyl carbamate)-3,7-dimethyl-7-methoxy-2E-octene). The inhibition patterns of T. ni and T. molitor are similar, while those of M. domestica are relatively different. Further studies on the juvenile hormone and α-napthyl acetate esterases of T. ni showed that they could be differentially inhibited. Diisopropyl phosphorofluoridate and an alkyl trifluoromethyl ketone selectively inhibit the hydrolysis of α-naphthyl acetate and juvenile hormone, respectively, while O-ethyl-S-phenyl phosporamidothiolate inhibits both enzymes. The juvenile hormone esterases of T. ni also appear to be unique enzymes that are selective for juvenile-hormone-like molecules. The in vivo inhibition of T. ni juvenile hormone esterases by O-ethyl-S-phenyl phosphoramidothiolate slows the in vivo hydrolysis of juvenile hormone and results in delayed pupation and malformed larvae that resemble larval-pupal intermediates. Thus, the esterases involved in juvenile hormone metabolism appear to be important in juvenile hormone regulation.     

Physiological actions of dinoterb,a phenol derivative: 2. Effects on isolated plant mitochondria and chloroplasts

Dinoterb, a contact herbicide, affects respiration and photosynthesis of mitochondria and chloroplasts. On mitochondria, at low concentrations, it acts as an uncoupler of oxidative phosphorylation; at higher concentrations, it inhibits the electron transport chains, probably before cytochrome c. On chloroplasts, dinoterb has a stimulatory effect on oxygen uptake in the reduced dichlorophenol-indophenol→methyl viologen couple; however, it is also an inhibitor of the Hill reaction and its site of inhibition is located before plastoquinone, near photosystem II.     

Studies on bovine demodecosis in northern Nigeria

Summary The study reported in the present paper discusses the clinical and histological picture of bovine demodecosis and the morphology of Demodex mites as seen in four cows suffering from generalized demodecosis. There were no clinical signs of other skin affections. Changes in both the number and the appearance of visible skin lesions were seen and related to the level of nutrition and the exposure to sunshine of the cattle. Histological sections of some skin nodules showed the presence of mite colonies in the hair follicles. Only adults were seen in the sebaceous glands. Microscopical study of the morphology of the mites revealed the presence of two types of demodicids in the skin lesions and three types from epilated eyelashes. Morphological criteria are presented to aid in identification of species and of life stages.     

Precocene II metabolism: Comparative in vivo studies among several species of insects,and structure elucidation of two major metabolites

Several species of insects, exhibiting varying responsiveness to the juvenile hormone antagonist precocene II (6,7-dimethoxy-2,2-dimethylchromene), were challenged topically with a tritiated preparation of the title compound. Metabolism of [³H]precocene II was subsequently examined by withdrawing hemolymph samples from treated animals at appropriate time intervals and characterizing the extractable radiolabel chromatographically. Quantitative (or qualitative) differences observed between the respective metabolic profiles were found not correlative with specimen sensitivity to precocene. Production of two heretofore unreported metabolites, identified by spectral and chemical means as O-β-glucosides of 6- and 7-monodemethylated precocene II, was demonstrated in both sensitive and insensitive species. No evidence for the presence of a hemolymphborne, biologically effective “activated metabolite” produced in vivo by precocene-susceptible insects could be found. The latter finding may well argue for in situ bioactivation of precocene at the target tissue(s) by these sensitive insects.     

The effect of some Frescon analogs on the aquatic snail,Lymnaea stagnalis: II. Correlation of neurotoxicity to Molluscicidal effectiveness

Although the molluscicide Frescon is a strong neurotoxin to the Lymnaea stagnalis central nervous system in vitro, it is probable that the exposure of the whole animal to this molluscicide fails to result in central nervous system abnormalities: Frescon does not appear to reach the brain in sufficient quantity to disrupt its normal activity. However, only those Frescon analogs found to be neurotoxic were molluscicidal, suggesting some related mode, if not site, of action. Frescon and its analogs may act by affecting excitable tissues other than the nervous system (e.g., the snail musculature) by altering certain functional and/or structural membrane properties.