共查询到20条相似文献，搜索用时 281 毫秒
1.
Post-emergence applications of glyphosate [N-(phosphonomethyl)glycine] have been shown not to eradicate purple nutsedge (Cyperus rotundus L.) in the field. It was not known if this was due to failure to control emerged plants or if dormant tubers produced new plants after application. Studies with individual plants were conducted in screenhouse facilities to determine the effects of glyphosate rate, time for translocation, area of foliage treated, and shade on the sprouting ability of tubers attached to treated plants. Rates of 1.5–2.0 kg/ha glyphosate inhibited tuber sprouting; 72 h were required for complete translocation at 1.0 kg/ha whereas 36 h were sufficient at 2.0 kg/ha. Treating less than all of the foliage reduced foliar control and increased tuber sprouting. Shading treated plants reduced control of the foliage but did not affect glyphosate translocation to the tubers. These studies showed that glyphosate kills C. rotundus foliage and the tubers attached to treated plants. Therefore, regrowth after glyphosate application under field conditions is due to dormant tubers which sprout after treatment. 相似文献
2.
Established Greenhouse grown plants of cogongrass Imperata cylindrica (L) Beauv.) and purple nutsedge (Cyperus rotundusL.) were given three different soil moisture regimes; field capacity, moderate stress and extreme stress, followed 6 weeks later by glyphosate [(N-phosphonomeihyl) glydne] applications to the shoots at 0.2,0.4 and 0.8 kg/ha for Imperata and 0.3,0.6 and 1.12 kg/ha for Cyperus. Field capacity watering stimulated most vegetative growth in hoth species. Glyphosate given at field capacity decreased shoot dry weight in both species, and rhizome length, rhizome dry weight and total carbohydrate in Imperata and total number of tuber-bulbs in Cyperus. In contrast. at extreme soil moisture stress, glyphosate showed reduced activity which appeared to be related to the physiological and morphological behaviour of the plants arising from the drought trealment. Application of waier to the roots of the plants grown at soil moisture stress. I week before and I week afler glypbosate spraying, enhanced glyphosate activity, probably because of the recovery of processes disturbed by ibe soil moisture deficit. 相似文献
3.
MENASHE HOROWITZ 《Weed Research》1972,12(4):348-363
Summary. Single tubers of Cyperus rotundus L. were planted at intervals over the year. Plant growth was slow and sprouting of tubers was inhibited at temperatures below 20°C, but tubers overwintered at temperatures above freezing point. In the warm season, plant growth and tuber formation rate closely followed air temperature and tubers were forming within 1 month from planting. No inflorescence appeared during the cool season. In autumn-planted C. rotundus grown in containers, the ratio of aerial to subterranean weight decreased from 1·1 in December to 0·2–0·4 in summer. The weight of tubers in mid-summer was about 10 times more than that present in December. Tubers formed at ail times of year and at various locations on plants sprouted readily in laboratory tests (76–100% sprouting). C. rotundus planted in March at wide spacings was grown in field conditions free of other plant competition for 20 months. Within 2 months the plants had spread to 90 cm. At the end of the first and the second summer of growth, the mean area of one plant was 7·6 m2 and 56·7 m2, respectively, and patches had expanded then by 2·8 m and 5·4 m, respectively, from the initial shoot. After 20 months of growth all tubers were present within the 0–40 cm soil depth, 60–70% of them in the 0–20 cm layer. About 30% of the tubers were within 1 m and 60% within 2 m of the plant centre. Under the patch centre there were about 1000 tubers per m2 with 0·3 kg dry weight; in the upper 20 cm more than 3500 tubers weighing 0·9 kg were present per m3 of soil. Croissance, formation de tubercules et propagation de Cyperus rotundus L. issu de tubercules uniques 相似文献
4.
Naptalam applied to yellow nutsedge (Cyperus esculentus L., var leptostachvus Boeck.) plants through nutrient culture, as a foliar spray or to the soil surface significantly stimulated the transformation of rhizomes into new shoots when the plants were grown under a 20-h photoperiod. Applications of naptalam to plants grown under short-day conditions inhibited tuber production. Applications of glyphosate to yellow nutsedge foliage at 0·3 and 0·6 kg ha resulted in 57 and 68% dormant tubers respectively, compared to 27% in untreated plants. These lower rates did not significantly increase the number of nonviable tubers. The application of 1·1 and 2·2 kg ha resulted in 47 and 52% dormant tubers, respectively and approximately 40% nonviable tubers. When production of new shoots of yellow nutsedge was induced by soil treatment with napialam and followed later with glyphosate significantly greater control of the nutsedge was observed than from either herbieide alone. Effets du naptalame sur la crossance du experus aune et efficaeite ulterieure du glyphosate. Le naptalame appliquè sur des plantes de cypérus jaune (Cyperus esculentus L. var leptostachyus Boeck) a vee des éléments nutritifs, en pulvérisation fobaire ou à la surface du sol a significativement stimulé la transformation des rhizomes en nouvelles pousses forsque les plantes ont été soumises à une photopériode de 20 h. Les applications de naptalame aux plantes pousant dans des conditions de jours courts ont inhibe la production des tubercules. Des applications de glyphosate sur le feuillage du cypérus jaune à 0.3 et 0.6 kg ha ont donné respectivement 57 et 68% de tubercules dormants contre 27% chez les plantes non traitées. Ces doses plus faibles n'ont pas augmente significativement le nombre de tubercules nonviables. L'application de 1.1 et 2.2 kg ha a donné respectivement 47 et 52% de tubercules dormants, et approxativement 40% de tubercules non viables. Lorsque la production de nouvelles pousses de cypérus jaune a été induite par un traitement du sol au naptalame. suivi ulterieurement d'une application de glyphosate. l'efficacite observée sur le cypérus a été significativement meilleure qu'avee l'un ou l'autre de ces herdicides employé soul. Der Einfluss von Naptalam auf das Wachstum von Cyperus esculentus L. und nachfolgender Bekämpfung mit Glyphaxate Wird Naptalam in die Nähelösungskultur oder auf das Blatt von Cyperus esculentus var leptostachyus Boeek, sowj?e auf die Bodenoberfläche appliziert so stimulieri es die Bildung von neuen Trieben aus Rhizomen, wenn die Pflazen einer Photoperiode von 20 Std. ausgesetzt werden. Unter Kurztagshedingungen hemmt Napralam die Bildung von Knollen Wurde Naptalam auf die Blätter mít 0.3 und 0.6 kg ha appliziert so stieg die Zahl der dormanten Knollen von 27% bei unbehandelt auf 57% und 68% bei behandelt. Diese niedrigen Aufwandmengen steigerten die Zahl der keimfähigen Knollen nicht significant. Die Applikation von 1.1 und 2.2 kg ha resultiere in 47 und 52% dormanten und 40% nicht keimfähigen Knotlen. Wenn die Bildung von Trieben durch eine Behandlung mit Naptalam über dem Boden induziert wurde und diese nachfolgend mit Bekämpfungserfolg als wenn jades Herbizid allein angewandt wurde. 相似文献
5.
Research conducted in El Salvador, Central America, demonstrated that an interval of 3 days between application of glyphosate and tillage was sufficient to cause 90% reduction in purple nutsedge (Cyperus rotundus L.) plants, while delays of 11–23 days generally gave slightly less reduction. à second application to the same plots 35 days following tillage resulted in more than 90% reduction with all intervals. Approximately 3 months after the initial treatment, tuber numbers had been reduced to half the original population. Germination of the remaining tubers was reduced by more than 50%. Glyphosate applied during the dry season caused an average of 79% reduction in plant numbers compared with 88% in the rainy season. However, in the dry season, the remaining plants had no competition from other weeds and after 5 months there was only à 40% reduction in nutsedge population. During the rainy season, 1, 2 and 3 kg/ha were equally effective, but 1 kg/ha was not sufficient in the dry season. 相似文献
6.
Various control strategies for Achillea millefolium L. (yarrow) were investigated in a dense stand of the weed at Lincoln College in 1977–1978. In early spring plots were either rotary cultivated or left undisturbed. In late spring, plots of both previous treatments were either left undisturbed, rotary cultivated or sprayed with glyphosate at 1·5 kg ha?1. The whole experiment was rotary cultivated twice 1 week later and sown with Hordeum vulgure L. cv. Zephyr (barley) at 144 kg seed ha?1. MCPA + dicamba at 0·9+0·15 kg ha?1 was applied to half of each plot when the second node was detectable (Zadok 32). Rotary cultivation and glyphosate both substantially reduced the regrowth of A. millefolium but glyphosate reduced regrowth by a greater proportion when applied to undisturbed plants than when applied to plants regenerating after cultivation. Both gave a more than 95% reduction compared to the control (rotary cultivation only at sowing time) in the amount of A. millefolium present in the barley stubble in the autumn. MCPA + dicamba caused seedling mortality but did not affect the numbers of primary shoots from rhizome fragments. The grain yield of the barley increased from 2·91 t ha?1 when A. millefolium was not controlled to 4·23 t ha?1 with good control. The barley yield appeared to be restricted by competition from regenerating A. millefolium and by a nitrogen deficiency induced in some regimes by nitrogen immobilization in decaying rhizomes. 相似文献
7.
E. W. STOLLER 《Weed Research》1973,13(2):209-217
Summary. The response of tubers to low temperatures was investigated to gain insight into a physiological basis for the differential distribution of Cyperus esculentus L. (yellow nutsedge) and C. rotundus L. (purple nutsedge) in the United States. Only C. esculentus tubers survived the winter of 1968–69 in the field at Urbana, Illinois. Less than 10% of C. rotundus tubers survived at 2°C for 12 weeks, whereas more than 95% of C. esculentus tubers survived this treatment. Exposures to -2°C for 4 h or longer killed 50% of C. rotundus tubers, whereas - 6·5°C was required to kill 50% of C esculentus tubers. C. rotundus distribution is restricted to regions where the soil seldom freezes, whereas C. esculentus is distributed in regions where the soil temperatures often get below freezing. Survival of C. esculentus tubers in soil which frequently freezes may account for its wide distribution. Death of C. rotundus tubers in soils which freeze apparently is the reason why the species is restricted to the southeastern and southwestern regions of the U.S.A. L'Influence de la température du sol sur la répartition différentielle de Cyperus rotundus et de Cyperus esculentus aux Etats-Unis 相似文献
8.
ROBERT D. WILLIAMS 《Weed Research》1982,22(3):149-154
The growth of both species (as characterized by their total dry weight, inflorescence dry weight, root and rhizome dry weight and number of shoots per pot) was similar, but they differed in the manner in which the dry weight was partitioned to reproductive structures. Each species partitioned less than 2% of its dry weight into floral formation. However, yellow nutsedge (Cyperus esculentus L.) partitioned only 28% of its dry weight to tubers, whereas purple nutsedge (C. rotundus L.) partitioned 50% of its dry weight to fewer and larger tubers. The allocation of dry weight to reproductive structures was related to changes in day-length. Yellow nutsedge tuber formation increased as day-length decreased from 14.5 to 12.5 h, while floral formation did not begin until the day-length dropped below 14 h. Purple nutsedge formed inflorescences earlier and production continued throughout the remainder of the study, but tuber formation was curvilinear and accelerated as the day-length decreased. 相似文献
9.
Potato (Solanum tuberosum) production in Africa is rapidly expanding and becoming increasingly important. As its geographical production range broadens, so does its potential to host new pests and diseases. Following the discovery that potato can be affected by Scutellonema bradys, further studies were undertaken to assess its potential pathogenicity on potato under screenhouse and field conditions, and on marketed tubers. Potato plants inoculated with S. bradys produced tubers with substantial cracking and evident tuber rot, compared with tubers from uninoculated plants. Symptoms of nematode infection on tubers included a scaly appearance, surface cracking as well as deeper tissue cracks, distortions, and darkened surface patches. In most cases these patches were related to sub‐surface rot. Nematodes were recovered from the soil, roots and tubers of inoculated plants. Eight weeks after inoculation, the reproduction factor of the nematode was greatest (2·0) at the lowest inoculation rate assessed (1000 nematodes per 2·5‐L pot) and least (0·4) at the highest inoculation rate (5000 nematodes per pot). In the screenhouse, potato tuber weights were low and mostly unaffected by nematode inoculation rate, except at 5000 nematodes per pot. In the field, non‐inoculated plants yielded over nine times more tubers than plants inoculated with 2000 S. bradys. Low densities of S. bradys were also recovered from 10 of 15 (67%) samples collected from market stalls, indicating field infection. This study confirms that potato can host and be damaged by S. bradys, raising its prospect as a likely significant biotic constraint to the crop. 相似文献
10.
N.C.B. PETERS 《Weed Research》1985,25(1):67-77
A study was made of the caryopsis weights of Avena fatua grown in the field and in pots and of the competitive ability of A. fatua from heavy seed (≥18 mg) and light reed (≤11 mg) grown at a depth of either 25 or 75 mm with spring barley sown at 25 mm. The weight of field- and pot-grown caryopses of A. fatua types fA, fB and fC ranged from 3 to 25, 5 to 23, and 5 to 25 mg respectively. With one exception, both the field- and pot-grown samples showed a double normal distribution pattern. The mean weights of pot-grown primary and secondary caryopses of fA, fB and fC were 15 and 9, 19 and 11, and 18 and 11 mg respectively. In a competition experiment, A. fatua grown from heavy seeds sown at 75 mm depth with an equal number of barley produced 47% more panicles, 54% more seed and 56% more dry weight per plant than plants from light seeds. When barley and both seed weights of A. fatua were sown at 25 mm depth these differences were smaller, being 21, 28 and 34% respectively. When the barley was at Zadoks stage 87, and when the barley and A. fatua were grown at equal densities at 25 mm depth, the dry weight of barley was reduced from 10·4 to 7·7, and to 5·8 g per plant by light- and heavy-seeded A. fatua, respectively. When the barley was grown at 25 mm and the A. fatua at 75 mm, the weight per barley plant was reduced to 9·5 and 7·2 g by A. fatua plants grown from light and heavy seeds respectively. Reductions in numbers of grain were caused mainly by a reduction in the number of fertile heads. 相似文献
11.
JOHN L. HAMMERTON 《Weed Research》1975,15(3):177-183
Soil-incorporated butylate, EPTC and vernolate had only small effects on nutgrass (Cyperus rotundus L.) shoot numbers and the germination of recovered tubers. MSMA, 2,4-D, glyphosate and cyperquat all killed top growth and reduced the germination of recovered tubers in both field and pot trials. Naptalam increased shoot number and tuber production. Foliar sprays of abscisic acid, chlorflurenoi and CCDP (3-carboxy-1-(p-chlorophenyl)-4,6-dimethyl-2-pyridone) had little or no effect. Ethephon slightly increased the number of attached tubers with shoots, but NIA 10637 (.ethyl hydrogen-1-propylphosphonate) had inconsistent efl'ects. MH inhibited tuber bud germination, TIBA increased shoot numbers slightly, and daminozide reduced tuber production and the germination of detached tubers. None of the growth regulators tested appears potentially useful for nutgrass control. Expériences avec le Cyperus rotundus L. II. Action de quelques herbicides et substances de croissance Le butylate, l'EPTC et le vernolate incorporés au sol n'ont eu que peu d'efficacité contre le cyperus (Cyperus rotundus L.) en ce qui concerne le nombre de pousses et la germination des tubercules récoltés. Le MSMA, le 2,4-D, le glyphosate et le cyperquat ont tous détruit la zone terminale de croissance et réduit significativement la germination des tubercules récoltés dans les essais, soit au champ, soit en pots. Le naptalame a augmenté le nombre de pousses et la production de tubercules. Des pulvérisations sur les feuilles d'acide abscissique, de chlorflurénol et de CCDP (3-carbo.xy-1-(p-chlorophényl)-4,6-diméthyl-2-pyridone) n'a eu que peu ou pas d'effets. L'ethéphon a légérement accru le nombre de tubercuies fixés aux racines, mais le NIA 10637 (hydrogéne-1-propylphosphonate d'éthyle) n'a eu que des effets incohérents. L'hydrazide maléique a inhibé la germination du bourgeon du bulbe, le TIBA a accru légérement le nombre de pousses, et le daminozide a réduit la production des tubercules et la germination des tubercules détachés. Aucune des substance de croissance essayées n'apparait potentiellement utilisable pour la lutte contre le cyperus. Versuche mit Cyperus rotundus L. II. Wirkung einiger Herbizide und Wachstumsregulatoren In den Boden eingearbejtetes Butylat, EPTC und Vernolat hatte nur eine geringe Wirkung auf die Anzahl der Sprosse und den Austrieb der Knollen von Cyperus rotundus L. MSMA, 2,4-D, Glyphosate und Cyperquat toteten die oberirdischen Pflanzenteile ab und verringerten den Austrieb der Knollen in Feld- als auch in Gefässversuchen. Naptalam bewirkte eine Zunahme der Sprosszahl und erhöhte die Knollenbildung. Blattspritzungen mit Abscisinsäure, Chlorflurenoi und CCDP (3-Carboxy-1-(p-chlorphenyl)-4,6-di-methyl-2-pyridon) hatten eine geringe oder gar keine Wirkung. Durch Ethephon nahm die Anzahl der Knollen mit Sprossen zu, NIA 10637 (Äthyl hydrogen-1-propylphospho-nat) hingegen zeigte widersprüchliche Wirkungen. MH hemmte den Austrieb der KnoUenknospen, TIBA förderte leicht die Zahl der Sprosse und Daminozid verringerte die Knollenbildung und den Austrieb abgetrennter Knollen. Von den gepruften Wachstumsregulatoren scheint keiner fur die Bekampfung von Cyperus rotundus geeignet zu sein. 相似文献
12.
In order to clarify the growth and reproductive success of seed‐derived Sagittaria trifolia individuals emerging at different times within a season, seeds were sown on May 16, June 16 and July 22 2010 and allowed to grow in pots under shaded and unshaded conditions. The timing of when the first inflorescence of each seedling appeared was recorded, as well as the number of seeds and tubers produced and the dry weight of each organ. In total, 220 seedlings were used, 23–59 in each treatment. As the sowing time was delayed, so too was the appearance of the first inflorescence. Additionally, the number of inflorescences, fruits and seeds produced by the unshaded plants significantly decreased with the sowing time. The total dry weight was significantly greater in the unshaded than in the shaded plants: the July‐sown, shaded plants grew very poorly. The relative resource allocation to the tubers was greater in the late‐emerging, shaded seedlings. Even in the shaded groups, except for the July‐sown plants, most of the plants set seed. Therefore, when addressing weed control in paddy fields, one should keep seedlings in mind, in addition to plants that have grown from tubers. 相似文献
13.
Yellow nutsedge variants from California, Georgia, Illinois, Maryland, Minnesota and Oklahoma were analysed for intraspecific differences in tuber composition. Tuber size varied from 70 to 710 mg. Carbohydrates ranged from 45 to 77% of tuber dry weight. Starch was the most abundant carbohydrate in all the tubers. The saccharides, fructose, glucose, sucrose and melibiose were found at least in trace quantities in all the tubers; only tubers of the Georgia and Maryland variants contained significant quantities of all four saccharides, and the other three variants containted principally sucrose. Triglycerides constituted more than 80% of the lipids in the tubers. The major acid present in all tubers was oleic. Composition du tubercule chez divers biotypes de Cyperus esculentus (L.) Des biotypes de Cyperus provenant de Californie, de Géorgie, de l'Illinois, du Maryland, du Minnesota et de l'Oklahoma ont été analysés en vue de rechercher des différences intraspécifiques dans la composition du tubercule. Le poids du tubercule a varié de 70 à 710 mg. Les hydrates de carbone représentaient de 45 a 77% du poids sec du tubercule. L'amidon a été l'hydrate de carbone le plus abondant dans tous les tubercules. Les saccharides: fructose, glucose, saccharose et mélibiose ont été trouvés au moins à l'état de traces dans tous les tubercules; seuls les tubercules des biotypes de Géorgie et du Maryland contenaient des quantités significatives des quatre saccharides et les trois autres biotypes contenaient principalement du saccharose. Les triglycérides constituaient plus de 80% des lipides des tubercules. Le principal acide gras présent dans tous les tubercules était l'acide oléique. Inhaltsstoffe der Knollen verschiedener Herkünfte von Cyperus esculentus (L.) Herkünfte von Cyperus esculentus aus Kalifornien, Gorgia, Illinois, Maryland und Oklahoma wurden auf Unterschiede in ihrer Knollenzusammensetzung untersucht. Die Knollenge-wichte variierten zwischen 70 und 710 mg. Die Kohlenhydratgehalte schwankten von 45 bis 77% des Knollentrockengewichtes. Stärke war in alien Knollen das häufigste Kohlenhydrat. Die Saccharide Fructose, Glucose, Sucrose und Melibiose waren in alien Knollen zumindest in Spuren festzustellen. Lediglich Knollen aus Gorgia und Maryland enthielten größere Mengen aller 4 Saccharide. DieTestlichen 3 Herkünfte enthielten haupt-sächlich Sucrose. Triglyceride bildeten mehr als 80% der Knol-lenlipide. Die häufigste Fettsäure war Ölsäure. 相似文献
14.
为明确刈割对油莎豆（Cyperus esculentus L.）地上部碳氮积累、生物量、地下部块茎产量和品质的影响,寻求适宜留茬高度,以新疆沙区油莎豆为研究对象,比较6个不同留茬高度（LC10、LC20、LC30、LC40、LC50和未刈割）下油莎豆地上部碳氮积累及产量和品质的差异。结果表明：刈割后第1天,LC50有利于叶片碳氮含量的积累,碳、氮含量分别达到 22.79%和1.65%;刈割后第5天至20天,LC10和LC20叶片碳氮含量急剧下降;刈割后第5天和第10天,LC40的全碳和全氮含量高于其他处理,分别为39.78%、38.39%和1.48%、2.12%。LC40地上部干草质量和干豆质量最大,分别为4 310.39 kg·hm-2和8 208.90 kg·hm-2,且LC40块茎淀粉、粗蛋白、粗脂肪含量以及含油量显著高于其他处理,增幅分别为38.6%、28.8%、6.0%、22.44%,此外,该留茬高度下油莎豆块茎中不饱和脂肪酸油酸含量高达74.10%,明显高于其他处理。LC10 块茎中总糖与粗灰分含量最高,分别达到44.4%和2.3%,且块茎中棕榈酸、硬脂酸、棕榈油酸、亚麻酸和亚油酸含量相对其他处理较高,分别为14.00%、2.99%、0.28%、0.42%、11.21%。综上所述,留茬高度40 cm为适宜刈割高度,利于提高新疆沙区油莎豆的产量和品质。 相似文献
15.
MENASHE HOROWITZ 《Weed Research》1972,12(3):207-220
Summary. Early development of Cynodon dactylon (L.) Pers, was studied on one-node rhizome fragments planted at successive dates over a year. Aerial growth followed the changes in external temperature; in the cool season tops grew very slowly but remained alive. New rhizomes were formed only at temperatures exceeding 15–20°C. Flowering occurred in the warm season from May onwards. No relationship was found between flowering and rhizome formation. The age of plants forming new rhizomes decreased from 5 months for the January planting to less than 2 months for the May-September plantings. Rhizome bud germination was maximal between 23 and 35°C, slow below 20°C and inhibited at 10°C. The weight ratio of tops to subterranean parts of established plants was near 1 in winter, declined in March-April and remained at 0·5–0·6 from May onwards. An established sward of C. dactylon was sampled from September to November of the following year. Dry weight was lowest from January to mid-April, rose in spring and decreased in late summer. Almost no rhizomes were found deeper than 45 cm. Underground parts from the 0–15, 15–30 and 30–45 cm horizons constituted 62, 26 and 12% of the total weight, respectively; rhizomes formed more than 90% of the total underground dry weight. In the warm season the dry weight of the subterranean organs amounted to 2, 0·7 and 0·4 kg/m3 of soil in the three horizons, respectively. Percent dry matter in tops and subterranean parts was about 35–45% in the winter and 50–65% in the warm season. Up to 2% reducing sugars was found in various parts of the plants. The water-soluble sugar content of rhizomes was high in November-December, decreased in late winter, rose again in spring, and decreased in late summer. Percent germination of rhizome buds fluctuated greatly during the year, but complete dormancy was never recorded. Newly-formed rhizomes showed a high germinative capacity. Similar germination percentages were found on fragments with one node and those with several nodes. Développement du Cynodon dactylon (L.) Pers. 相似文献
16.
Control of Cyperus rotundus with glyphosate: the influence of ammonium sulphate and other additives 总被引：1，自引：0，他引：1
Glyphosate was applied to Cyperus rotundus L. in combination with a range of other herbicides and certain non-herbicidal additives. Most herbicides tended to have an antagonistic effect with glyphosate, especially those which inhibit photosynthesis. On the other hand 2,4-D amine and aminotriazole showed at least additive and sometimes synergistic effects. Striking activation was obtained with ammonium sulphate added at rates between 1·25 and 10 kg/ha. Other compounds causing almost equal activation were several ammonium phosphates, ammonium butyl-phosphate and urea. The activity of glyphosate on C. rotundus was considerably greater when applied 3 weeks after planting than at 9 weeks. The activation was also greater at 3 weeks but was still apparent at 9 weeks. Lutte contre le Cyperus rotundus avec el glyphosate: influence du sulfate d’ammonium et d'autres adjuvants Le glyphosate a été appliqué au Cyperus rotundus L. en association avec une série d'autres herbicides et certains adjuvants non-herbicides. La plupart des herbicides manifestèrent un effet antagoniste avec le glyphosate, particulièrement ceux qui inhibent la photosynthèse. D'autre part, le 2,4-D sel d'amine et l'aminotriazole montrérent des effets au moins additifs et quelquefois synergiques. Une activation frappante fut obtenue avec le sulfate d'ammonium ajoutéà des doses comprises entre 1,25 et 10 kg/ha. D'autres produits ont provoqué une activation à peu près équivalente: plusieurs phosphates d'ammonium, le butylphosphate d'ammonium et l'urée. L'efficacité du glyphosate sur C. rotundus a été considérablement plus élevée lorsqu'il a été appliqué 3 semaines après plantation, au lieu de 9 semaines. L'activation fut aussi plus grande à 3 semaines, mais était encore apparente à 9 semaines. Bekämpfung von Cyperus rotundus mit Glyphosate: Der Einfluss von Ammoniumsulfat und anderen Zusätzen Cyperus rotundus L. wurde mit Glyphosate in Kombination mit einer Reihe anderer Herbizide und bestimmter nicht-herbizider Zusätze behandelt. Die meisten Herbizide zeigten mit Glyphosate die Tendenz einer antagonistischen Wirkung, insbesondere solche, die die Photosynthese hemmen. Andererseits wirkten 2,4-D-Amin und Aminotriazol zumindest additiv und manchmal auch synergistisch. Eine beeindruckende Aktivierung wurde mit Ammoniumsulfat bei Aufwandmengen zwischen 1·25 und 10 kg/ha erreicht. Andere Verbindungen, die eine fast gleichwertige Aktivierung bewirkten, waren verschiedene Ammoniumphosphate, Ammoniumbutylphosphat und Harnstoff. Die Aktivität von Glyphosate war beträchtlich höher, wenn es 3 Wochen, statt 9 Wochen nach dem Pflanzen angewendet wurde. Die Steigerung war zwar nach 3 Wochen grösser, war aber auch noch nach 9 Wochen festzustellen. 相似文献
17.
The effect of glyphosate on leaves and basal bulbs of yellow nutsedge (Cyperus esculentus L.) plants was studied. Treatment with glyphosate did not affect leaf anatomy, although light necrotic spots were seen on the veins. In contrast, basal bulb organization was greatly affected with large necrotic zones and disorganization in the vascular cylinder due to herbicide accumulation. Depletion or disappearance of vacuolar phenols was observed in bulbs of plants treated with the highest doses of glyphosate. The most remarkable effect of glyphosate was the appearance of one layer of sclerenchymatic cells between root and rhizome primordia and the cortical tissues which could play an important role in the inhibition of rhizome and root emergence by the herbicide. 相似文献
18.
19.
Metoxuron was more active when Bromus sterilis L. (sterile brome) plants were kept under cool (10/6°C day/night) compared with warm (26/16°C) temperatures after spraying. The effect of warmer temperatures required exposure for more than 3 days. Metoxuron activity was unaflected by a cold exposure (0/-2°C or 4/2°C) for a 24-h period shortly before or after spraying. Greater damage occurred when plants were kept in high relative humidity (r.h.) (95/98% r.h. day/nighl) after spraying than at 75/86% r.h. or at 50/75% r.h. Increasing soil moisture from 11.5 to 21.5 g water 100 g?1 dry soil also resulted in increased metoxuron activity. Metoxuron was less active under severe shading. There was little evidence in these studies that metoxuron activity resulted from foliar uptake. Results are discussed with reference to field reports of metloxuron use against B. sterilis. L. 相似文献
20.
Structure-concentration–foliar uptake enhancement relationships between commercial polyoxyethylene primary aliphatic alcohol (A), nonylphenol (NP), primary aliphatic amine (AM) surfactants and the herbicide glyphosatemono(isopropylammonium) were studied in experiments with wheat (Triticum aestivum L.) and field bean (Vicia faba L.) plants growing under controlled-environment conditions. Candidate surfactants had mean molar ethylene oxide (EO) contents ranging from 5 to 20 and were added at concentrations varying from 0·2 to 10 g litre?-1 to [14C]glyphosate formulations in acetone–water. Rates and total amounts of herbicide uptake from c. 0·2–μl droplet applications of formulations to leaves were influenced by surfactant EO content, surfactant hydrophobe composition, surfactant concentration, glyphosate concentration and plant species, in a complex manner. Surfactant effects were most pronounced at 0·5 g acid equivalent (a.e.) glyphosate litre?-1 where, for both target species, surfactants of high EO content (15–20) were most effective at enhancing herbicide uptake: surfactants of lower EO content (5–10) frequently reduced, or failed to improve, glyphosate absorption. Whereas, at optimal EO content, AM surfactants caused greatest uptake enhancement on wheat, A surfactants gave the best overall performance on field bean; NP surfactants were generally the least efficient class of adjuvants on both species. Threshold concentrations of surfactants needed to increase glyphosate uptake were much higher in field bean than wheat (c. 2 g litre?-1 and < 1 g litre?-1, respectively); less herbicide was taken up by both species at high AM surfactant concentrations. At 5 and 10 g a.e. glyphosate litre?-1, there were substantial increases in herbicide absorption and surfactant addition could cause effects on uptake that were different from those observed at lower herbicide doses. In particular, the influence of EO content on glyphosate uptake was now much less marked in both species, especially with AM surfactants. The fundamental importance of glyphosate concentration for its uptake was further emphasised by experiments using formulations with constant a.i./surfactant weight ratios. Any increased foliar penetration resulting from inclusion of surfactants in 0·5 g litre?-1 [14C]glyphosate formulations gave concomitant increases in the amounts of radiolabel that were translocated away from the site of application. At these low herbicide doses, translocation of absorbed [14C]glyphosate in wheat was c. twice that in field bean; surfactant addition to the formulation did not increase the proportion transported in wheat but substantially enhanced it in field bean. 相似文献