ALBERT

Notes: The foliar penetration of four alkyl oleates (methyl to butyl) and their influence on the penetration of phenmedipham and quizalofop-P-ethyl was studied in barley (Hordeum vulgare L.), cleavers (Galium aparine L.) and pea (Pisum sativum L.). Loss of alkyl oleates from glass and plant surfaces was inversely related to the length of the alkyl chains and was assumed to be due to volatilization. All four alkyl oleates after application alone, readily penetrated into pea and barley leaves but much less into G. aparine. Penetration of methyl oleate appeared to be faster than that of butyl oleate. Both alkyl oleates were completely metabolized in barley and pea in 27 h, but not in G. aparine. The penetration of herbicides was from 2% to 10% in the absence of alkyl oleates. The penetration of phenmedipham was increased in the presence of all four aikyl oleates: to the greatest extent into pea (55-80% after 27 h), to the lowest into G. aparine (20-45%). In all three species, the effect of butyl oleate was higher than that of methyl oleate. The penetration of quizalofop-P-ethyl was increased to 10%, 30-35% and 50% on G. aparine, pea and barley respectively. The length of the alkyl chains did not influence the effects of the alkyl oleates on the foliar penetration of quizalofop-P-ethyl.

Notes: The action of 23 herbictdal substituted ureas on the growth of excised tomato roots was studied in order to détérmine whether there is a link between the effects of these herbicides on oxidative phosphorylation and on the growth of non-photosynthetic tissues. Fourteen of these herbicides were inhibitory; chlortoluron and TBU were stimulatory but only in the light. Substituted ureas known to affect plant mitochondria inhibited root growth but to a lesser extent than some which had no action on mitochondria. No clear relationship was found between actions on mitochondria and on root growth. It is suggested that targets other than photosynthesis and oxidative phosphorylation exist for some substituted ureas.

Notes: Methyl ester derivatives of seed oils have a greater effect on graminicide efficacy than the parent oils. To explain this difference, we investigated the penetration of the radiolabelled oils, triolein (TRI) and methyl oleate (MEO), in maize leaves, and their influence on diclofop-methyl penetration. Over a period of 3 h 30% of applied TRI penetrated maize leaves, but no further penetration was observed. In contrast, MEO entry proceeded regularly to 72% over a period of 27 h. The amount of oil found in epicuticular wax (chloroform wash) was generally less than 4% of the recovered label, and was even lower (〈1%) in ‘glossy 1’ hybrids which have no crystalline epicuticular wax. In the latter plants, TRI and MEO penetration over 27 h was only 1 and 27%, respectively. Addition of an emulsifier did not modify the behaviour of the oils. The initial rate of penetration of radiolabelled diclofop-methyl into maize leaves was dramatically increased by both oils (7-5-fold by TRI, 11.8-fold by MEO). The penetration of diclofop-methyl in the leaves of ‘glossy’ hybrids was low (4% over 27 h), and it was not affected either by TRI or by the emulsifier, whereas MEO increased it sevenfold. This preliminary study shows the differences in behaviour and effect that may exist between seed oils and their methyl ester derivatives, and it emphasizes the importance of cuticular structure with regard to oil action. Utilization des huiles végétales comme adjuvants: pénétration dans les feuilles de maïs de la trioleïne, du méthyloleate et du diclofop-méthyl Les dérivés méthylestérifiés d'huiles végétales ont un effet plus important sur l'efficacité des herbicides antigraminées que les huiles d'origine. Pour expliquer cette différence, nous avons étudié la pénétration de deux huiles radioactives, la trioléine (TRI) et le méihyloléate (MEO) dans les feuilles de maïs, ainsi que leur effet sur la pénétration du diclofop-méthyl. En 3 h, 30% de TRI appliquée pénétrait les feuilles de maïs mais aucune pénétration ultérieure n'était observée. Au contraire, la pénétration de MEO se poursuivait régulièrement jusqu'à 72% en 27 h. La quantité d'huile trouvée dans les cires épicuticulaires (lavage au chloroforme) était généralement inférieure à 4% de la radioactivité récupérée, et inférieure à 1% chez les maïs ‘glossy 1’ qui n'ont pas de cires épicuticulaires cristallines. Dans ces dernières plantes, la pénétration de TRI et MEO était, respectivement, de seulement 1 et 27% en 27 h. L'addition d'un émulgateur ne modifiait pas le comportement des huiles. La vitesse initiale de pénétration du diclofop-méthyl radioactif dans les feuilles de mais était augmentée de manière importante par les deux huiles (TRI: × 7,5; MEO: × 11,8). La pénétration du diclofopméthyl dans les feuilles des hybrides ‘glossy’était faible (4% en 27 h). Elle n'était affectée ni par TRI ni par l'émulgateur alors que MEO l'augmentait (×7). Cette étude préliminaire montre les différences de comportement et d'effet qui pourraient exister entre huiles végétales et leurs dérivés méthyl ester; elle souligne aussi l'importance de la structure cuticulaire dans l'action des huiles. Aus Samen gewonnene Öle als Additive: Penetration von Triolein, Methyloleat und Diclofopmethyl in Maisblätter Methylester von aus Samen gewonnenen Ölen verbessern die Wirksamkeit von Graminiziden mehr als die Grundstoffe. Um diese Unterschiede genauer zu erkennen, wurde die Penetration der radioaktiv markierten Ole Triolein (TRI) und Methyloleat (MEO) in Maisblätter und ihr Einfluβ auf die Aufnahme von Diclofop-methyl untersucht. In 3 h wurden 30% des applizierten TRI von Maisblättern aufgenommen, aber eine weitere Aufnahme wurde nicht festgestellt. Im Gegensatz dazu wurde MEO innerhalb 27 h kontinuierlich bis zu 72% aufgenommen. Die Menge des in der epikutikularen Wachsschicht gefundenen Öls (Lösung in Chloroform) war allgemein 〈4% der wiedergefundenen Radioaktivität und war sogar geringer (〈 1%) in ‘Glossy-1’-Hybriden, die kein kristallines epikutikulares Wachs haben. Bei solchen Pflanzen lag die TRI- und die MEO-Penetration in 27 h bei nur 1 bzw. 27%. Durch Zugabe eines Emulgators konnte das Verhalten der Öle nicht geändert werden. Die anfängliche Aufnahmerate für das radioaktiv markierte Diclofop-methyl in Maisblättern wurde durch beide Öle auβerordentlich gesteigert (TRI: 7,5 mal; MEO: 11,8 mal). Die Penetration von Diclofop-methyl in die Blätter der ‘Glossy’-Hybriden war gering (4% in 27 h). Durch TRI oder den Emulgator wurde sie nicht beeinfluβt, mit MEO jedoch gesteigert (7mal). Diese vorläufige Untersuchung zeigt Unter-schiede in Verhalten und Wirkung der Öle und ihrer Methylester, und sie unterstreicht die Bedeutung der kutikularen Strukturen für die Wirkung von Ölen.

Notes: I‘activité biologique d'un résidu de synthese du diuron, identi-fiéåla 1.3-his-(3,4-dichlorophényl) urée. a éiéétudiée sur E. coli. mitochondries de pomme de terre. chloroplasies et lipo-somes.Ce composé inhibe la croissanee d'E. coli et semble modifier les permétions membraires. II ayit comme un découplant trés actif des oxydations phosphorylames: il bloque la réaction de Hill de chloroplastes isoles et modifie les pro-priété des membranes liposomales. Cette activité est comparée à celle dea diuron technique et purifié et peut †tre responsablede certames actions du diuron technique.

Notes: L'action de 24 urées substituées et du propanil a étéétudiée sur mitochondries de tubercules de pommes de terre et sur membranes phospholipidiques artificielles (liposomes). Tous les produits sont actifs sur mitochondries á 10−3m. Le néburun, le siduron, le chlorbromuron, le buturon, le linuron, le fenobenzuron, le monolinuron et le propanil sont découplants á 10−4m; le chloroxuron et le TBU agissent comme inhibiteurs du transfert d'électrons. La concentration diminuant de 50% la valeur du P/O est 50 μm pour le néburon, 65–70 μm pour le siduron, 150–200 μm pour le chlorbromuron et 100 μm pour le chloroxuron; les autres produits ont un effet moindre.Seuls les produits découplants sur mitochondries (auxquels il faut ajouter le chloroxuron) augmentent la perméabilité de la membrane des liposomes au pottassium et dans certains cas aux protons. II existe une bonne corrélation entre les activités découplantes sur mitochondries et sur liposomes. Die Wirkung substituierter Harnstoffe auf die oxidative Phosphorylierung der Mittochondrien von Kartoffelknollen (Solarium tuberosum L.). Vergleich mit der Wirkung auf Liposomen.Es wurde die Wirkung von 24 substituierten Harnstoffen und von Propanil auf Mitochondrien von Kartoffelknollen und auf künstliche phospholipidhaltige Membranen (Liposomen) untersucht. Alle Verbindungen sind bis 10−3m auf Mitochondrien wirksam Bei 10−4m wirken die folgenden Verbindungen als Entkoppler: Neburon, Siduron, Chlorbromuron, Buturon. Linuron, Fenobenzuron. Monolinuron und Propanil; Chlortoluron und TBU wirken wie Hemmer des Eiektronentransports Die Konzentration. die zu einer Verminderung des P/O-Werts führt, betràt 50 μm für Neburon, 65–70 μm für Siduron, 150–200 μm für Chlorbromuron und 100 μm für Chloroxuron; die anderen Verbindungen haben eine geringere Wirkung.Nur die Verbindungen. die bei Mitochondrien entkoppelnd wirken (hierzu muss auch Chloroxuron gerechnet werden) erhöhten die Permeabilität der Liposomenmembranen für Kalium und in bestimmten Fällen für Protonen. Es besteht eine gute Korrelation zwischen der entkoppelnden Wirkung bei Mitochondrien und bei Liposomen The effects of substituted urea herbicides on phosphorilant oxidations of mitochondria of potato tubers (Solanum tuberosum L.): comparisons with the effect on liposomes.The action of twenty-four substituted urea herbicides and of propanil on mitochondria of potato tubers and on artificial phospholipid membranes (liposomes) was studied. All the products were active on mitochondria at 10−3m. At 10−4m, neburon, siduron, chlorobromuron, buturon. linuron, fenobenzuron, monolinuron and propanil were decoupling: chlorotoluron and TBU behaved as inhibitors of electron transfer. The concentration causing 50% drop in the value of P/O was 50 μm for neburon, 65–70 μm for siduron, 150–200 μm for chloro-bronuron and 100μm for chloroxuron. The other products had less effect, Only the products decoupling on mitochondria (to which must be added chloroxuron) increased the permeability of the liposome membrane to potassium and in certain cases to protons. There was a good correlation between decoupling activity on mitochondria and on liposomes.† Avec la collaboration technique de J. L. Dufour. Abréviations utilisées. ADP; adénosine 5’diphosphate; ATP: adénosine 5’triphosphate; SAB: sérum albumine bovine; EDTA: acide éthylénediaminotétracétique; DMSO: diméthylsulfoxyde; TBU: terbutyl N 4-phényl, N'diméthylurée, R.C.R.: rapport de contrôle respiratoire.

Notes: It has long been known that calcium ion antagonizes glyphosate, but it was not clear whether the stoichiometry of their interaction is 1:1 or 1:2. Two independent methods were used to determine which stoichiometry was the most probable. First, dose–response curves of barley (Hordeum vulgare L.) plants treated with glyphosate were determined in the presence of 0, 1.25, 2.5, 5 and 10 mM CaCl2. The doses of ‘free’ glyphosate (=not inactivated by calcium ion) were computed using the assumptions of 1:1 and 1:2 stoechiometries. The response curves were redrawn as a function of ‘free’ glyphosate. Analysis showed that the 1:2 hypothesis could be rejected, whereas the 1:1 hypothesis was highly probable. Second, kinetics of glyphosate penetration into barley leaves were determined in the presence of 0, 2.5 and 10 mM CaCl2. The concentrations of ‘free’ glyphosate were computed as above. The kinetics of glyphosate penetration at these concentrations were established and were compared to the kinetics of glyphosate penetration in the presence of CaCl2. Again, the 1:2 hypothesis was rejected, whereas the 1:1 hypothesis was more probable. These results strongly suggest that the stoichiometry of the Ca2+:glyphosate association is 1:1 in deposit residuals on the leaf surface.

Notes: The foliar surface of 4-leaf maize plants was found to be poorly wettable and retained 106 μl g−1 dry matter when sprayed with a U46D (2,4-D formulation) blank. The third leaf retained 141 μl g−1. A 7-day cold spell (17/9°C) increased retention per unit dry matter by 53% (135% on the third leaf). Cold stress lowered epicuticular wax quantity by 29% on the third leaf. Contact angles of formulated 2,4-D lay between 115 and 125° and were not significantly affected by cold stress. 2,4-D rapidly entered into maize third leaf (66% in 24 h) but migration from it was less than 1.5%. 2,4-D was readily degraded in maize (80% in 72 h). The most abundant metabolite was probably an ester conjugate; little of the hydroxy derivatives were found. Cold stress reduced 2,4-D degradation, and 72 h after treatment the amount of undegraded 2,4-D was 78% higher in cold-stressed maize plants. It was concluded that 2,4-D selectivity in maize results from low spray retention per unit dry matter and active degradation of penetrated herbicide. Cold stress affects both factors.

Notes: The action of chlorfenprop-methyl, chlorfenprop and its cysteine conjugate was studied on potato tuber mitochondria. Chlorfenprop-methyl altered membrane structure at 250 μM. leading to a loss of membrane integrity. Chlorfenprop and its cysteine conjugate were without any significant effects. From what is known about the rapid hydrolysis of chlorfenprop-methyl in plant tissues and from the results presented in this paper, it was deduced that alteration in intra-cellular membrane integrity is not a mechanism of phytotoxic action for chlorfenprop-methyl.