bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biology of Commelina benghalensis L. in south‐eastern Queensland. 1. Growth, development and seed production
Authors: WALKER S. R. , EVENSON J. P. 
Published: July 2006

SummaryExperiments conducted at Kingaroy in southeastern Queensland, investigated growth, development and seed production of Commelina benghalensis L. a weed of field crops, which produces aerial and underground flowers. Plants were grown from four seed types (large and small seeds from the two types of flowers) in pots exposed to the weather and in the field.Development was faster, and growth and seed production were greater in the field than in pots. Plants grown from aerial seeds were smaller, developed aerial flowers earlier, and produced more aerial fruits than plants grown from underground seeds. Rhizomes and underground flowers began to develop 6 weeks after emergence on plants from all seed types, prior to the development of aerial flowers. Seed production in the field was 8000 m−2 for plants grown from underground seeds and 12000 m−2 for plants grown from aerial seeds. Small aerial seeds represented 73–79% of the total seed production, large aerial seeds 19–22%, and underground seeds only 1–3%.
Germination, emergence and seedling growth of Hypericum perforatum L.
Authors: CAMPBELL M. H. 
Published: July 2006

SummaryGermination of new seeds (1–6 months old) of Hypericum perforation L. was restricted by high temperatures (16h/8h, 20/30°C), darkness and a chemical inhibitor in exudate from the capsule, whereas germination of old seeds (9 years) was only restricted by the inhibitor. The effect of the chemical inhibitor and high temperatures was overcome, respectively, by washing seeds in water and by reducing temperatures to constant 15°C. Calcium in solution from CaCO3 and from three different soils did not prevent the germination of new or old seeds or of seeds collected from five different locations. There were differences in the germination characteristics and dormancy mechanisms of seeds collected from different localities, Restriction of the emergence of seedlings by a covering of > 2 mm of soil appeared to be due to lack of seedling vigour rather than to lack of light. Seedling growth was much slower than in other pasture species. Thus the requirements for germination of H. perforatum of low temperature and moisture to wash away the chemical inhibitor favour its establishment but the slow growth of its seedling restricts its emergence and renders it extremely susceptible to competition from other plants.
Effect of mixed function oxidase inhibitors on the toxicity of chlortoluron and isoproturon to wheat
Authors: GAILLARDON P. , CABANNE F. , SCALLA R. , DURST F. 
Published: July 2006

SummaryGrowth responses of wheat plants to combined treatments of four mixed function oxidase (MFO) inhibitors and chlortoluron were determined. Analysis of interactions showed that piperonyl‐butoxide and especially ABT (1‐aminobenzotriazole) increased the toxicity of chlortoluron. Metyrapone and 2,4‐dichlorophenoxypropyne were phytotoxic and did not exert any clear interaction. ABT also increased the toxicity of isoproturon to wheat.Our results suggest that ABT Strongly inhibits the breakdown of chlortoluron and isoproturon in wheat. Since ABT is known to act as a suicide substrate for plant cytochrome P‐450, wheat enzymes involved in the metabolism of these two herbicides are likely to belong to this class. It thus appears that compounds designed to inhibit plant cytochrome P‐450 enzymes may interact with herbicide metabolism and are potential synergists of herbicide activity.
Control of Sorghum halepense (L.) Pers. in cotton with post‐emergence herbicides and trifluralin
Authors: KURTZ M. E. 
Published: July 2006

Summary: Résumé: ZusammenfassungA field experiment was conducted in 1981 and 1982 to evaluate five post‐emergence herbicides applied alone or following a preplant incorporated application of trifluralin for the control of Sorghum halepense (L.) Pers. in cotton (Gossypium hirsutum). One application of the methyl ester of haloxyfop [methyl 2‐ (4‐ ((3‐chloro‐5‐trifluoromethyl)‐2‐pyridinyl)oxy)phenoxy)pro‐panoate], trifluralin plus the ethyl ester of DPX‐Y6202 [ethyl[2‐[‐4‐(6‐chloro‐2‐quinoxalinyl)oxy]phenoxy]propionate], the butyl ester of fluazifop and trifluralin plus haloxyfop resulted in over 90% control of S. halepense just prior to harvest in 1981 and 1982. Sorghum halepense control was similar whether the post‐emergence herbicides were applied alone or following preplant incorporated trifluralin at 0.8 kg ha−1. La lutte contre Sorghum halepense (L.) Pers. en culture de cotonnier moyennant des herbicides de post‐levée et la trifluralineUne expérience a été installée en plein champ en 1981 et 1982 dans le but d'évaluer cinq herbicides de post‐levée, appliqués seuls ou suite à la trifluraline incorporée avant le semis, dans la lutte contre Sorghum halepense (L.) Pers. en culture de cotonnier (Gossypium hirsutum). Une seule application de l'haloxyfop ester de méthyle [méthyle 2‐(4‐((3‐chloro‐5‐ (trifluorométhyle)‐2‐pyridinyle) oxy)phénoxy)propanoate], de trifluraline + DPX‐Y6202 ester d'éthyle (éthyle[2‐[4‐(6‐chloro‐2‐quinoxalinyle)oxy]phénoxy)propionate), de l'ester butylique du fluazifop et de trifluraline + haloxyfop a permis en 1981 et 1982 une bonne maîtrise (90%) de S. halepense juste avant la récolte. La maîtrise de Sorghum halepenseétait semblable, que les herbicides de postlevée aient été précédés ou non d'une application de trifluraline à 0,8 kg ha−1 incorporée avant le semis. Bekämpfung von Sorghum halepense (L.) Pers. in Baumwolle mit Nachauflaufherbiziden und TrifluralinIn den Jahren 1981 und 1982 wurden Feldversuche zur Bekämpfung von Sorghum halepense (L.) Pers. in Baumwolle (Gossypium hirsutum) mit fünf Nachauflaufherbiziden durchgeführt. Die Herbizide wurden allein oder nach einer vor der Baumwollsaat erfolgten Einarbeitung von Trifluralin appliziert. Eine Applikation des Methylesters von Haloxyfop [Methyl‐2‐(4‐((3‐chloro‐5‐(trifluormethyl)‐2‐pyridinyl)oxy)phenoxy)propanoat]. Von Trifluralin + Aethylester von DPX‐Y 6202 [Aethyl[2‐[‐4‐(6‐chlor‐2‐quinoxalinyl)oxy)phenoxy)propionat], des Butylesters von Fluazifop und Trifluralin + Haloxyfop ergaben in beiden Jahren kurz vor der Ernte eine über 90 ige Kontrolle von S. halepense. Der Bekämpfungserfolg war ähnlich, gleichgültig ob die Herbizide allein oder nach der Einarbeitung von Trifluralin (0,8 kg ha−1) appliziert worden waren.
Diversité floristique et biologie des adventices de la région du Tadla (Maroc)
Authors: TANJI A. , BOULET C. 
Published: July 2006

Résumé: Summary: ZusammenfassungDans le but d'inventorier les adventices des cultures de la région du Tadla (Maroc Central), 345 champs cultivés ont fait l'objet de relevés phytoécologiques. Trois cent trente espèces adventices appartenant à 50 familles botaniques ont ainsi pu être identifiées: 84% sont des dicotylédones (essentiellement Compositae, Leguminosae, Cruciferae, Caryophyllaceae, et Umbelliferae) et 73% sont des annuelles. Une brève étude agronomique a permis de distinguer 70 espèces ayant une nuisibilité non négligeable vis à vis des différentes cultures de la région. Inventory and biology of cropland weeds of the Tadla region (Morocco) An inventory of cropland weeds of the Tadla region (Central Morocco) was made, based on samples from 345 cultivated fields. Three hundred and thirty species were identified, belonging to 50 botanical families: 84% of the species were dicots (mainly Compositae, Leguminosae, Cruciferae, Caryophyllaceae, and Umbelliferae), and 73% were annuals. Seventy species are important cropland pests. Ueber die Floristik und Biologie der Unkräuter in der Region von Tadla (Marokko) Ziel dieser Studie war eine Inventaraufnahme der Ackerunkräuter in der Region Tadla (Zentral‐marokko); zu diesem Zweck wurden in 345 Feldkulturen phytoökologische Bestandesaufnahmen durchgeführt. Dabei wurden 330 Unkrautarten aus 50 Familien identifiziert; davon waren 84% Dikotyledonen (hauptsächlich Compositen, Leguminosen, Cruciferen, Caryophyllaceen und Umbelliferen) und 73% Anuelle. 70 Arten verursachten in verschiedenen Kulturen starke Schädigungen.
Abscisic acid as a protectant of Avena fatua L. against diclofop‐methyl activity
Authors: FIELD R. J. , CASELEY† J. C. 
Published: July 2006

SummaryThe imposition of water stress before or al the time of spraying diclofop‐methyl reduced efficacy against wild oat (Avena fatua L.). Similar reductions in herbicide performance were obtained by application of 20 μg of the methyl ester of abscisic acid (ABA) to plants with three to four leaves before spraying with I kg ha−1 diclofop‐methyl. Application of 40–100 μg ABA per plant effectively protected plants against damage from diclofop‐methyl applied at 1 5–2 0 kg ha −1. The application of 20 μg ABA induced rapid stomatal closure and a reduction in leaf extension rate, which were sustained for 7–8 days after treatment. These changes were associated with an overall reduction in shoot growth. ABA‐treated plants that were additionally sprayed with diclofop‐methyl sustained ABA symptoms, but no additional weight loss or leaf chlorosis. The mechanism of the protective action of ABA on diclofop‐methyl has not been determined.
Effects of drying and dl‐strigol on seed conditioning and germination of Striga asiatica (L.) Kuntze
Authors: HSIAO A. I. , WORSHAM A. D. , MORELAND D. E. 
Published: July 2006

SummarySeeds of Striga asiatica (L.) Kuntze required 7 and 14 days at 30°C to become conditioned when they were immersed in water and 10−8mdl‐strigol, respectively. At least 80% of seeds so conditioned germinated with 10−8mdl‐strigol as a terminal stimulation treatment. Seeds that were first immersed in water for 2 days, then subjected to one to three drying periods of 2 days each, either separately or continuously, required only 2 days of water immersion to become conditioned. Seeds first immersed in 10−8mdl‐strigol, then subjected to one or two drying periods, required only 3–4 days of water immersion as compared to a 14 days’requirement without drying treatments. The seeds first immersed in water or 10−8mdl‐strigol and then dried, plus one or two 10−8mdl‐strigol immersions, required 4 days of water immersion to become conditioned. However, the seeds immersed in various combinations of water or 10−8mdl‐strigol solutions plus one, two or three drying periods of 2 days each required 6 days of water immersion to become conditioned. The results indicate that the interaction of prolonged drying treatments and dl‐strigol immersions delay conditioning processes in the seeds. Both water immersion and short drying treatments, however, seem to enhance certain required processes that occur during conditioning, thereby reducing the time required for the seeds to become conditioned when re‐immersed in water.
Influence of environmental factors on the performance of sethoxydim against Elymus repens (L.)
Authors: COUPLAND D. 
Published: July 2006

SummaryThe performance of sethoxydim on Elymus repens (L.) Gould was studied under contrasting levels of humidity, light intensity, temperature, soil moisture and simulated rainfall using controlled environment chambers. Over a 24‐h post‐spraying period, increases in humidity and temperature markedly enhanced herbicide performance, while effects of light intensity were less pronounced. Soil moisture deficit significantly reduced herbicide performance, but there were no adverse effects of wet soil conditions (twice field capacity) on activity. The effects of simulated rain depended upon herbicide dosage, time interval between spraying and the onset of rain, and rain intensity. A low rain intensity of 0.5 mm h−1 did not reduce herbicide performance even when applied 10 min after spraying. The longer term studies, over 4 weeks, showed increases in herbicide activity with higher temperatures but lower light intensities.
Joint action of root‐absorbed mixtures of auxin herbicides in Sinapis alba L. and barley (Hordeum vulgare L.)
Authors: STREIBIG J. C. 
Published: July 2006

SummaryThe efficacy of some binary mixtures of MCPA, 2,4‐D dichlorprop, mecoprop and dicamba was evaluated in water culture experiments. Within each of seven assays, two dose‐response curves described the phytotoxicity of the herbicides administered separately and three curves described the phytotoxicity of mixtures in fixed ratios. A non‐linear regression model of dry matter on the logarithm of the dose, assuming the five response curves to be mutually parallel, was fitted and a reference model, the Additive Dose Model (ADM) to assess the efficacy of the mixtures, was also incorporated into the regression. The biological interpretation of ADM is often associated with mixtures of compounds having similar mode of action. Mixtures of dicamba with dichlorprop or 2,4‐D were more potent than expected under ADM in two Sinapis alba assays. In one assay with mixtures of MCPA and dichlorprop the parallel‐line model fitted somewhat better than did the ADM regression. This also applied to a barley assay with mixtures of dicamba and MCPA. On the basis of the results obtained it is suggested that the analogy between the implicit assumptions of the parallel‐line assay can be extended to the ADM. Parallel dose response curves are a necessary but not a sufficient condition for assuming similar mode of action Similarly, it can be argued that mixtures of compounds following ADM are a necessary but not a sufficient condition for assuming a similar mode of action for the herbicides in a mixture.
Persistence of GR7 and Striga germination stimulant(s) from Euphorbia aegyptiaca Boiss. in soils and in solutions
Authors: BABIKER A. G. T. , IBRAHIM NADIA E. , EDWARDS W. G. 
Published: July 2006

SummaryThe activity of GR7 and Striga germination stimulant(s) from Euphorbia aegyptiaca Boiss. showed adequate persistence (6–8 days) in acidic soils (pH 5·0–6·3), but residual activity was short (1–3 days) in alkaline soils. The compounds tended to lose activity at a faster rate in the alkaline clay Gezira soil (pH 7·8), than in its sandy equivalent (pH 8·1). In solution, pH had no influence on initial activity, but residual action was reduced more rapidly by alkalinity and high temperature. However, the rate of loss of activity in solution was slower than in soils.
Effects of some commercial herbicides on rhizobia and their symbiosis with peanuts
Authors: KISHINEVSKY B. , LOBEL RINA , LIFSHITZ N. , GURFEL DEBORA 
Published: July 2006

SummaryFour herbicides commonly used in Israel for controlling weeds in peanuts were evaluated under field and screenhouse conditions. Terbutryn (Terbutrex 50, w.p.), ethalfluralin (Sonalan 333, e.c.), dinitramine (Cobex 240, e.c.) and alachlor (Alapaz 480, e.c.), used at recommended levels, had no adverse effect on nodulation rate, nitrogenase activity, total nitrogen of peanut tops or pod yield, compared with control (inoculated but herbicide non‐treated) plants. Studies were conducted to determine the relative toxicity in vitro of the herbicides on each of four Rhizobium strains used for commercial peat inoculant production. The results showed that at up to 94 μg g−1 the herbicides has no inhibitory effect on the growth of rhizobia. The sensitivity of Rhizobium strains to different rates of the chemicals decreased in the order: dinitramine>alachlor>ethalfluralin>terbutryn. It was found that various strains differ in their sensitivity to the herbicides tested.
Survival and growth of seedlings of Rumex obtusifolius L. and Rumex crispus L. in newly sown grassland
Authors: HONGO A. 
Published: July 2006

SummaryThe survival and growth of seedlings of Rumex obtusifolius L. and Rumex crispus L. were investigated from 1982 to 1984. A sward was established by the sowing of seeds of Dactylis glomerata and Trifolium repens and managed under two cutting frequencies. Five hundred seeds of each Rumex species were sown m−2. The total number of emergent seedlings of each Rumex species over two seasons was 230–360 m−2. About 85% of them emerged within 3 months of sowing. Both Rumex species showed the same pattern of survivorship. Survival was clearly enhanced by frequent cutting during the second season. About 20% of the emerged plants survived through to the third season. Plants that emerged during the first season only flowered during the second season. The flowering percentage of total surviving plants was significantly higher in R. obtusifolius than in R. crispus. Rumex obtusifolius was higher in dry matter of aerial parts defoliated during the second season and more individual plants survived through to the third season than for R. crispus. Moreover, dry matter production of grass and clover was depressed by 25–30% in mixtures with R. obtusifolius. compared with production in mixtures with R. crispus.
On robust weed population models
Authors: MORTIMER A. M. , SUTTON J. J. , GOULD P. 
Published: July 2006

SummaryDifference equation models incorporating density dependence are considered in the context of the description of the dynamics of weed populations over discrete generations. Their applicability is assessed in relation to modelling yield loss, two species and three species interactions and the influence of density independent control practices. Analysis indicates that whilst plant populations may show simple dynamical properties around equilibrium levels, convergent oscillations to equilibrium may result from the application of control measures. Such models are argued to have potential as robust qualitative predictors of weed species abundance.
Adsorption and degradation of chlorsulfuron and metsulfuron‐methyl in soils from different depths
Authors: WALKER A. , COTTERILL E. G. , WELCH SARAH J. 
Published: July 2006

SummaryAdsorption and degradation rates of chlorsulfuron and metsulfuron‐methyl were measured in soil taken from depths of 0–20, 20–40 and 40–60 cm at eight sites. Adsorption of both herbicides was negatively correlated with soil pH, and positively correlated with soil organic matter content. When two soils with very high organic matter were excluded from the calculations, the correlations with organic matter content were no longer statistically significant but those with soil pH were affected only slightly. Degradation rates of both herbicides generally decreased with increasing depth in the soil and were positively correlated with microbial biomass and negatively correlated with soil pH. The possible significance of the results to persistence of the herbicides in the field is discussed.
Effects of the safeners CGA 154281, oxabetrinil and fenclorim on uptake and degradation of metolachlor in corn (Zea mays L.) seedlings
Authors: KREUZ K. , GAUDIN J. , EBERT E. 
Published: July 2006

Summary. The influence of three crop safeners on the uptake and degradation of 14C‐metolachlor was investigated in two corn varieties. Following application of herbicide and safener together to seedling shoots the concentrations of non‐metabolized 14C‐metolachlor in the tissues was found to be lower in the tolerant variety LG 9 than in the susceptible variety 211A. The difference between varieties was due to differences in both uptake and degradation of 14C‐metolachlor.Following shoot application most of the radioactivity was retained in the coleoptile and the mesocotyl. Two hours after application 95% of the herbicide had been degraded in coleoptiles and mesocotyls, whereas approximately 20% of non‐metabolized 14C‐metolachlor was present in the enclosed developing shoot leaves. In both corn varieties the safener CGA 154281 caused a substantial lowering of tissue levels of parent 14C‐metolachlor. This was primarily due to an enhanced degradation. Glutalhione‐S‐transfer‐ase (GST) enzyme activity in shoot tissues was found to be enhanced in both varieties by CGA 154281. Oxabetrinil and fenclorim were less effective than CGA 154281 both in reducing tissue levels of non‐metabolized 14C‐metolachlor and in enhancing GST activity in either variety.
Abbau von Metsulfuron–methyl an verschiedenen Mineralien
Authors: SABADIE J. , BASTIDE J. 
Published: July 2006

Résumé:La dégradation chimique en phase séche du metsulfuron méthyle a étéétudiée à température ambiante au contact de trois solides minéraux (Kaolin, silice, Montmorillonite K10). L'acidité du support favorise l'activité. Deux grandes voies de dégradation ont été observées: hydrolyse directe de la fonction urée du metsulfuron méthyle; déméthylation du substituant méthoxy puis hydrolyse. La formation d'isocyanate intermédiaire est postulée dans tous les cas. La fonction carboxyméthyl demeure généralement inchangée.
Potentiel semencier et propriétés de sol des terres arables en Baviére
Authors: ALBRECHT H. , BACHTHALER G. 
Published: July 2006

Zusammenfassung:In der vorliegenden Arbeit wurden 140 Ackerfláchen aus 7 Regionen Bayerns auf ihr Samenpotential und ihre Bodeneigenschaften untersucht. Dabei zeigte sich, daß die Samendichte eng mit Faktoren der Bodenökologie korreliert ist. So fanden sich in basischen Substraten zumeist niedrige, in schluffigen und sandigen Böden mit mäßig saurer Reaktion mittlere und in stark sauren Sanden hohe Samengehalte. Sehr hohe Samenkonzentrationen wurden außerdem in saisonal vemäßten Äckern festgestellt. Diese Ergebnisse lassen sich dadurch erklären, daß sich unter bestimmten Bodenverhältnissen charakteristische Artenkombinationen entwickeln. Über eine artspezifische Samenproduktion entsteht somit auch ein für den Standort typisches Samenpotential.
Uptake, translocation and phytotoxicity of imazapyr and glyphosate in Imperata cylindrica (L.) Raeuschel: effect of herbicide concentration, position of deposit and two methods of direct contact application
Authors: TOWNSON JANE K. , BUTLER RUTH 
Published: July 2006

Summary:The activity of imazapyr and glyphosate against Imperata cylindrica was studied in field and glasshouse experiments using two methods of direct contact application; a rope‐wick wiper and a cloth soaked in herbicide solution. The effect of concentration and position of application on herbicide uptake and translocation was also measured. At the lowest dose of imazapyr (5 mg acid equivalent (a.e.) per plant), phytotoxicity was greater from applications by a rope‐wick wiper than by a cloth. However, when the dose of imazapyr was increased, the cloth applicator was more effective than the rope‐wick wiper. At all doses of glyphosate, rope‐wick application was more effective than wiping with a cloth. Herbicide performance in the glasshouse was similar to that in the field. Radiotracer studies showed that increasing the concentration of imazapyr, while keeping herbicide dose constant, decreased uptake and translocation of radiolabel. In contrast, the rate of uptake of 14C‐glyphosate increased with increasing herbicide concentration. Position of application did not significantly affect the amount of uptake and translocation of radiolabel to the rhizomes. It is concluded that rope‐wick wipers are more effective than wiping with a cloth for applying imazapyr and glyphosate to I. cylindrica, provided that the concentration of imazapyr does not exceed 10 g a.e. l−1.
Phenological development and biomass allocation inSilene vulgaris(Moench) Garcke
Authors: WALL D. A. , MORRISON I. N. 
Published: July 2006

Summary:Silene vulgaris (Moench) Garcke, grown from seed or from crown buds, exhibited three dis tinct growth phases; establishment, reproduc tive and post‐reproductive. The establishment phase was characterized by rapid accumulation of shoot biomass, high relative growth rates (RGRs) and leaf area ratios (LARs). The sexual reproductive phase was characterized by a rapid increase in floral and seed biomass, minimal root development, and declining RGRs and LARs. In the post‐reproductive phase, root and crown biomass increased rapidly concomitant with the development of regenerative buds; low RGR and LAR values occurred during this phase. Although similar growth phases were identified in both the first (grown from seed) and second years (grown from crown buds) of growth, LARs and RGRs were lower in the second than in the first year. In the second year of growth, plants exhibited a continual increase in below‐ground biomass throughout growth, including the flowering period, a feature which was absent in the first year of growth.