摘要:

Summary.The effect of paraquat (l,1′‐dimethyl‐4,4′‐bipyridylium‐24) on the ultra‐structure of mesophyll cells of honey mesquite (Prosopis juliftora (Swartz) DC. var.glandulosa(Torr.) Cockerell) was studied by means of electron microscopic techniques. The first visible change induced by the herbicide was a rapid disintegration of the plasmalemma, followed by rupturing of the chloroplast membranes and loss of chloroplast turgor. Changes that occurred in plants treated and sampled in the dark were similar to those in plants treated and sampled in the light.The only change of a biochemical nature detected was a marked reduction in the quantity of starch deposits in chloroplasts. No changes were noted in the mitochondria, Golgi bodies, endoplasmic reticulum or nucleus, or in the composition of the cytoplasm or cell walls of treated tissues.Effets du paraquat sur I'ultrastructure des cellules du mésophylle de ProsopisResumeL'action du paraquat (1,1′‐diméthyle‐4,4′‐bipyridylium‐2A) sur l'ultrastructure des cellules de mésophylle deProsopis (P. juliflora (Swartz) DC. var. glandulosa(Torr.) Cockerell) a été eatudiée au moyen des techniques de microscopie électronique. Le premier effet visible provoqué par l'herbicide fut une deasintegration rapide de la membrane cytoplasmique suivie de la rupture des membranes des chloroplastes et de la perte de la turgescence des chloroplastes. Les transformations qui apparurent dans les plantes traitées et conservées a l'obscurité, furent analogues á ceux des plantes traitées et exposées a la lumière.Le seul changement de nature biochimique deacelé fut une reduction marquée de la quantité des dépôts d'amidon dans les chloroplastes. Aucun changement ne fut observe dans les mitochondries, l'appareil de Golgi, le réticulum endoplasmique ou le noyau, pas plus que dans la composition du cytoplasme ou des parois cellulaires des tissus traités.Der Einfluss von Paraquat auf die Feinstru

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01456.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.Field experiments were conducted to find a herbicide for complete control of nutsedge (Cyperus rotundusL.). We applied seventeen herbicides and some of their combinations as chemical fallow. EPTC and CP‐31675 (6‐tert‐butyl‐2‐chloro‐o‐acetotoluidide) gave good but only temporary control of nutsedge. Dichlobenil at 2·5 or 5 lb/ac gave fair control for 1 year. Rates of 10 or 20 lb/ac of dichlobenil controlled nutsedge completely for 1 year but severely reduced the yield of oats planted 5 months after application. The highest rate completely killed tubers and prevented reinfestation for 1 year. Analyses indicated no residue of dichlobenil or of its metabolite, 2,6‐dichlorobenzoic acid, in vegetative parts and seeds of oats planted 5 months after application of 2.5, 5 or 10 lb/ac of dichlobenil. At equivalent rates the herbicide TH‐073‐H (N‐hydroxymethyl‐2,6‐dichlorothiolbenzamide) gave control of nutsedge similar to that with dichlobenil. The combinations of 8 lb/ac amitrole‐T and 10 lb/ac dichlobenil or TH‐073‐H were just as effective in controlling nutsedge shoots and tubers as dichlobenil or TH‐073‐H applied alone. The mixture of dichlobenil plus CP‐31675, each at 5 lb/ac, gave excellent control of nutsedge and tubers for 1 year. The herbicides terbacil (3‐ter‐Nbutyl‐5‐chloro‐6‐methyluracil) or Du Pont 733 (3‐tert‐butyl‐5‐bromo‐6‐methyluracil) at 10 lb/ac provided almost complete control of nutsedge. Application of terbacil to plants aged 4–6 weeks gave better results than application t

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01457.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.The growth of wild oat (Avena fatuaL.) was accompanied by an increase in the amount of spray retained per plant and per unit weight of plant, probably because the projected area (plan view) increased as the plant became larger. Flax (Linum usitatissimumL.) retained a fairly constant volume of spray per plant from the 8‐leaf to the 35–40‐leaf stages, so that the spray retained per unit plant weight decreased considerably as the plants grew. This was related to the decrease in projected area as a proportion of the whole. There was also a difference in retentivity between the cotyledons and true leaves; the cotyledons retained ten to twenty times more spray per unit weight. These results suggest that maximum selectivity would be achieved by spraying at an advanced stage of growth.Wild oat at the 3‐leaf stage retained more than half the aqueous spray in the two leaf axils, while flax retained most on the cotyledons. Distribution was shown to be a probable reason for selectivity. Addition of a surfactant greatly increased retention by both species, but although the effect of a spray on wild oat might thereby be increased, under certain conditions injury to flax might be increased and the margin of selectivity reduced.Croissance et retention des bouillies herbicides par la folle‐avoine et le lin en rapport avec la s

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01458.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.Model adsorbents were prepared by treating cellulose phosphate powder with a series of alkyltrimethylammonium compounds in which the size of the alkyl group was varied from C8to C18. The adsorption of linuron, atrazine and EPTC by these materials was found to increase logarithmically with increasing chain length. The extent of the adsorption was large compared with the adsorption of these herbicides by a humic acid and by a preparation made by removing the bulk of the inorganic constituents of a peat soil with a mixture of HCl and HF. Since soil organic matter is thought to contain alkyl groups, it is concluded that the possible influence of such groups should be considered in any discussion of the mechanisms involved in the adsorption of organic molecules by soils.Adsorption du linuron, de I'atrazine de l'EPTC par des adsorbants de la série aliphatique et des préparations organiques de s

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01459.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.In field screening trials for bananas (Musa acuminatavar. Dwarf Cavendish) in Hawaii, ametryne (2‐methylthio‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) was less phytotoxic to bananas than atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine). Sand culture experiments showed that both herbicides were equally injurious to banana plants. Differential degradation of the herbicides by the plants did not account for the phytotoxicity observed. Both herbicides were partly metabolized by the plant to their common hydroxyl derivative (hydroxyatrazine) and two other unidentified metabolites after 3 and 7 days of exposure to nutrient solution containing14C‐labelled ametryne and atrazine.Phytotoxicity was directly related to leachability of the herbicides and negatively related to adsorption capacity of each soil for the herbicides. Organic matter content seemed to be correlated to the response observed. It was postulated that phytotoxicity in the field may have been attributed to differential location of the herbi

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01460.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.The application of fluometuron, a phenylurea herbicide, at rates of up to 80 kg/ha a.i., to Shamouti orange, Washington Navel orange and Marsh Seedless grapefruit trees; and in rates of up to 16 kg/ha a.i. to young Sour orange seedlings, did not affect photosynthesis, respiration (as measured using the Warburg apparatus), dry weight and chlorophyll content of the leaves. Leaf‐disc experiments showed that when application is given more directly to the site of action, photosynthesis can be inhibited up to about 70% by 80 mg/1 of fluometuron. The level of inhibition is related to the application technique (shaking or infiltration), age of leaves and size of discs. The ability to inhibit photosynthesis was decreased in the demethylated derivatives of fluometuron. Translocation studies with14C‐fluometuron indicated that most of the radioactivity is accumulated in the root system and in the lower part of the stem. The citrus tree can be considered to be resistant to fluometuron; either the lack of translocation, or demethylation, or both may be the cause.RésuméLe fluométuron, herbicide à base de phénylurée, a été appliquéà des doses allaiit jusqu’à 80 kg/ha (m.a.) à des orangers ‘Shamouti’,‘Washington Navel’ et des pamplemoussiers ‘Marsh Seedless’, Pt jusqu'à 16 kg/ha (m.a.) sur de jeunes plantulas d'orangers ‘Sour’. La Photosynthèse, la respiration (mesurée avec l'appareil de Warburg), le poids sec et la teneur en chlorophylle des feuilles, n'ont pas été: modifiés. Des expériences faites sur des feuilles découpées en disques montitrèrent que si l'application est faite plus directement, la Photosynthèse peut être inhibée jusqu'à 70% par 80 mg/1 de fluométuron. Le degré d'inhibition est en relation avec la technique d'application (trempage ou infiltration), l'âge des feuilles on la taille des disques. Le pouvoir d'inhiber la Photosynthèse fut diminué dans les dérivés diméthylés du fluométuron. Des études de migration avec le fluométuron marqué au14C montrèrent que la plus grande part de la radioactivityé est accumulée dans le système racinaire et la plus faible part dans l'appareil aérien. Les citrus pcuvent être considérés comme résistants au fluométuron; la cause peut en etre soit l'absence de migration, soit la déméthylation, ou les deux à la fois.ZusammenfassungPhotosynthese, Respiration (gemessen mit dem Warburgapparat), Trockengewicht und Chlorophyllgehalt der Blätter wurden nicht beeinflusst durch die Applikation von Fluometuron, einen Phenylharnstoff, in Aufwandmengen bis zu 8o kg/ha A.S. bei Bäumen von Shamouti Apfelsinen, Washinglon Navel Apfelsinen und Marsh Seedless Grapefruit, sowie in Aufwandmengen bis zu 16 kg/ha A.S. bei jungen Keimpflanzen von Sour‐orange. Untersuchungen an Blattausschnitten ergaben, dass die Photosynthese durch 80 mg/1 Fluometuron bis zu 70% gehemmt werden kann, wenn die Applikation in der Nähe des Wirkungsorts erfolgt. Die Stärke der Hemmung ist abhängig von der Applikationstechnik (Schütteln oder Infiltration), dem Alter der Blätter und der Grösse der Blattausschnitte. Demcthylierte Derivate von Fluometuron hatten eine geringere Befähigung zur Photosynthesehemmung. Translokationsstudien mit14C‐Fluometuron liessen Erkennen, dass der grösste Teil der Radioaktivität in den Wurzeln und den unteren Sprosspartien angereichert wurde. Der Citrusbaum kann als resistent gegenüber Fluometuron gelten. Die Ursache hierfür kann entweder mange

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01461.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.When seeds of lettuce (Lactuca sativaL.) were placed on small squares of filter paper moistened with solutions of picloram (4‐amino‐3,5,6‐trichloropicolinic acid), the degree of inhibition on of root and hypocotyl elongation 72 hr later was related to picloram concentration. Inhibition was a useful parameter in determining quantities of picloram ranging from 0·03 to 7·2 μg. (Growth stimulation occurred from 0·00072 to 0·0072 μg. After paper chromatography of plant exudates containing14C‐labelled picloram, location and quantities of picloram on the chromatograms were determined by the lettuce bioassay and compared with determinations by the methods of ultraviolet light sensitivity,14C 4π strip scanning and14C dilution calculations. Rfvalues determined lay all methods were identical, and the quantitative determination by the bioassay agreed closely with the calculations based on the amount of14C detected by liquid scintillation counting.Un essai biologique rapide d'idntification et de dosage de piclorame en s

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01462.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

摘要:

Summary.Uptake, distribution and fate simazine (2‐chioro‐4,6‐biserthylamino‐s‐triazine) in 4‐year‐old seedlings of Norway spruce (Picea abies) are discussed. Simazine was found to be readily absorbed and distributed in the spruce seedlings. A positive relationship between the amount of simazine absorbed and the growth intensities of the plants indicates an active mechanism of uptake. A fixation of simazine in roots and sterm was observed.Simazine was degraded by roots and stem to hydroxysimazine and two other unknown metabolites. No simazine and only metabolites could be traced in the needles, indicating a very rapid rate of metabolism in the root system. The glucose derivative of benzoxazinone was extracted from all parts of the spruce seedlings and is probably responsible for the hydrolysis of simazine.The results indicate a very slow degradation of the metabolites to CO2as one of the f

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01463.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01464.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY

ISSN:0043-1737    

DOI:10.1111/j.1365-3180.1969.tb01465.x

出版商:Blackwell Publishing Ltd    

年代:1969

数据来源: WILEY