ALBERT

Notes: Summary. White ash (Fraxinus americana L.) trees, 2 years of age, treated continuously with 10 ppm picloram (4-amino-3,5,6-trichloropicolinic acid) in nutrient culture were only slightly injured after 4 weeks whereas red maple (Acer rubrum L.) trees were killed after only 2 weeks treatment.When the roots were exposed to 10 ppm 14C-picloram, the rate of root uptake, acropetal translocation in the stem, and accumulation in the leaves was much lower in the susceptible red maple than in the tolerant white ash. The foliar penetration and translocation of 14C-picloram applied to the leaves was very slight but similar in both species. Although a radiolabelled picloram metabolite was isolated from plant extracts, it was formed at equal rates in both species.It was concluded that the tolerance of white ash was not related to lower rates of picloram uptake or faster rates of picloram detoxication. It was postulated that the high susceptibility of red maple was due to a blockage of the xylem by picloram which caused death by a dessication of the leaves and upper stems. Action sélective du piclorame sur Fraxinus amerieana L. et Acer rubrum L.

Notes: The anatomy of the shoot system of red maple and white ash was examined at various times after treatment with picloram. Xylem blockage, enlargement of cortical and pith cells and eventual necrosis of the shoot apex, parenchymatous and phloem tissues of red maple plants were features shown by picloram treatment. Red maple shoots were desiccated and dead by 22 days after treatment commenced. White ash shoots showed some increased mitotic activity but at the end of 22 days of picloram treatment, the leaves were still turgid and the internal anatomy of the shoot system scarcely altered. It is suggested that the susceptibility of red maple plants can be explained in part by the effects picloram has on xylem blockage and necrosis of parenchymatous tissues in the shoot system of this species.Effects du piclorame sur l'analomie de la partie aérienne de l'erable rouge et du frêne blancL'anatomie de la partie aérienne de l'érable rouge et du frêne blanc a été examinee i diverses dpoques aprés un traitement au piclorame. Le blocage du xyléme, le grossissement des cellules corticales et médullaires, ainsi qu'une Éventuelle nécrose des apex des tiges, des tissus parenchymateux et du phloéme des Arables rouges furent les effects consécutifs au traitement par le piclorame. La partie aérienne des Arables rouges se déssécha et mourut 22 jours aprés le déA but du traitement. La partie aérienne du Fréne blanc manifesta un accrolssement d'activité mitotique. mais, 22 jours aprés le traitement au piclorame, les feuilles étaient encore turgesccntes et l'anatomie interne des organes aériens k peine altérte. II est suggéré que la sensibility de rérable rouge peut être expliquée en partie par les effets du piclorame sur le blocage du xyléme et les necroses des tissus parenchymateux dans les organes adriens de cette espèce.Die Wirkung von Picloram auf die Anatomic des Sprosses von Acer rubrum L. und Fraxinus americana L.Es wurde die Anatomie des Sprosssystems von Acer rubrum L. und von Fraxinus americana L. zu verschiedencn Zeiten nach einer PJilorambehandlung untersucht. Bei Acer rubrum traten als Sympiome auf: Verstopfen des Xylems, VergröBerung der Rinden-und Markzellen und schliesslich Absterben der Sprossspitze, des parenchymatischen und des Phloemgewebcs. 22 Tage nach der Behandlung waren dis Sprosse ausgelrocknet und tot. Bei Fraxinus americana zeigten die Sprosse erhohte mitotische AktivitSt, aber 22 Tage nach der Piclorambehandlung waren die Blotter noch turgeszent und der innere Auf bau des Sprols systems war kaum verSndert. Die Befunde deuten darauf hin, daβ die Empfindlichkeit von Acer rubrum gegenuber Pictoram zum Teil mit seiner Wirkung auf das Xylem und das parenchymatische Gewebe im Sproβsystem erklärt werden kann.

Notes: Summary. The efficacy of NN-diallyl-αα-dichloroacetamide (R-25788) as an antidote for reducing the injury of various herbicides in corn (Zea mays L.) was tested under controlled conditions in growth rooms. The application of R-25788 to the soil as a pre-plant incorporated treatment to corn significantly reduced the toxicity often out of twenty-two herbicides tested. These ten herbicides were, in order of decreasing effectiveness of the antidote, EPTC, barban, sulfallate, vernolate, molinate, butylate, alachlor, pebulate, linuron and di-allate. In quartz sand nutrient culture, R-25788 was more effective as an antidote for barban applied to the foliage of corn than it was for barban applied to the roots. Le NN-diallyl-αα-dichloroacétamide comme antidote de I'EPTC et autres herbicides dans le mais.

Notes: Summary In 2 separate experiments, solutions of DDT, 2,4-D + picloram and 2,4-D + 2,4,5-T were sprayed on fertile chicken eggs preceeding incubation. No treatments were found to cause any adverse effect on hatching success, incidence of malformed embryos or subsequent chick mortality relative to control groups. Weight gain of male chicks from eggs treated with DDT (1.1 kg/ha) and the 2,4-D + 2,4,5-T combination (1.1 and 11.2 kg/ha) was found to be greater than that of control chicks. No changes were noted with the females. Residue analysis verified pesticide penetration into the egg.