Bud inhibition of Cyperus rotundus L. tubers by inhibitor β or abscisic acid and the reversal of these effects by N-6-benzyl adenine*

The acidic ether fraction of methanol extracts from Cyperus rotundus L. (purple nutsedge) tubers contained inhibitory substances described hereafter as inhibitor β. Inhibitor β inhibited sprouting of excised C. rotundus buds and also the elongation of wheat coleoptiles. The inhibition of bud sprouting by inhibitor β was reversed by the application of N-6-benzyl adenine (BA). Applications of abscisic acid (ABA) also inhibited sprouting of the excised buds and this was similarly reversed by BA applications. Chromatographic evidence suggested that inhibitor β mainly consisted of phenolic materials and possibly ABA as a minor component. The role of BA in enhancing sprouting of C rotundus tubers is discussed. Inhibition des bourgeons de bulbes de Cyperus rotundus L. par I'inhibiteur β ou l'acide abscissique et réversion de ces effects par la N-6-benzyl adénine La fraction éther acide d'extraits, par le méthanol. de bulbes de Cyperus rotundus L. contient des substances inhibitrices decrites ci-après comme I'inhibiteur β. Cet inhibiteur β a inhibé la germination de bulbes isolés de C. rotundus ainsi que l'élongation de coléoptiles de blé. L'inhibition de la germination des bourgeons par I'inhibiteur βété renversée par l'application de la N-6-benzyl adénine (B.A.). Des applications d'acide abscissique (ABA) ont également inhibé la germination de bourgeons isolés et cet effet a été lui aussi renversé par des applications de B.A. Les chromatogrammes suggèrent que l'inhibiteur β est principalement constitué par des composés phénoliques et peut-être par I'ABA comme composant mineur. Le rôle de la B.A. dans l'inhibition de la germination des bulbes de C. rotundus est discuté. Knospenhemmung der Knollen von Cyperus rotundus L. durch Hemmstoff β oder Abscisinsäure und die Umkehrung dieser Effekte durch N-6-Benzylmlenin Die saure Fraktion aus methanolischen Extrakten von Cyperus rotundus L.-Knollen enthielten Hemmstoffe, die im folgenden als Hemmstoff β bezeichnet werden. Hemmstoff β hemmte das Sprossen isolierter C. rotundus-Knospen und die Streckung von Weizenkoleoptilen. Die Hemmung der Knospensprossung durch Hemmstoff β wurde durch An-wendung von N-6-Benzyladenin (BA) aufgehoben. Abscisinsäure (ABA) hemmte auch das Sprossen isolierter Knospen; durch BA wurde es auf ähnliche Weise aufgehoben. Der chromatographische Befund deutet darauf hin. Daß Hemmstoff β sich hauptsächlich aus phenolischen Verbindungen zusammensetzt und möglicherweise in gering-em Unfang ABA enthält. Die Rolle von BA auf die Förderung der Keimung von C. rotundus-Knollen wird diskutiert.     

Tolerance of adzuki bean to preplant-incorporated, pre-emergence, and post-emergence herbicides in Ontario, Canada

Weed management options for adzuki-bean growers in Ontario, Canada are limited due to few herbicide registrations. Four field trials were conducted at three locations in south-western Ontario in 2007 and 2008 to determine the tolerance of adzuki bean to several preplant-incorporated (PPI), pre-emergence (PRE), and post-emergence (POST) herbicides. All the herbicides were applied at the doses registered for use in soybean. The application of pendimethalin, cloransulam-methyl, and halosulfuron-methyl (PPI), flumetsulam, cloransulam-methyl, and halosulfuron-methyl (PRE), and acifluorfen and fomesafen (POST) caused ≤15% crop injury; however, the injury was transient and did not reduce the adzuki bean yield. The POST application of cloransulam-methyl and imazethapyr caused ≤23% crop injury and reduced the biomass by ≤50%, but did not reduce the plant height or crop yield. Metribuzin, flumetsulam, atrazine, and pyroxasulfone (PPI), metribuzin, linuron, pyroxasulfone, and atrazine (PRE), and bentazon, imazethapyr plus bentazon, halosulfuron-methyl, and thifensulfuron-methyl (POST) caused ≤61% crop injury. These treatments reduced the biomass, plant height, and crop yield. Based on these results, pendimethalin, cloransulam-methyl, and halosulfuron-methyl applied PPI, flumetsulam, cloransulam-methyl, and halosulfuron-methyl applied PRE, and acifluorfen and fomesafen applied POST might be potential weed management options for weed management in adzuki bean. Cloransulam-methyl and imazethapyr applied POST will need further evaluation due to phytotoxicity concerns. Metribuzin, flumetsulam, atrazine, and pyroxasulfone applied PPI, metribuzin, linuron, atrazine, and pyroxasulfone applied PRE, and bentazon, imazethapyr plus bentazon, halosulfuron-methyl, and thifensulfuron-methyl applied POST did not have an adequate margin of safety.     

The Intercarpal Ligaments of the Equine Midcarpal Joint, Part 2: The Role of the Palmar Intercarpal Ligaments in the Restraint of Dorsal Displacement of the Proximal Row of Carpal Bones

Objective— To determine the relative contributions of the palmar intercarpal ligaments in the midcarpal joint to the restraint of dorsal displacement of the proximal row of carpal bones.
Study Design— A biomechanical study of cadaver equine carpi.
Animals or Sample Population— Eight equine forelimbs from six thoroughbred horses.
Methods— With joints in full extension, the radius was dorsally displaced while midcarpal joint displacement was measured. The restraining force at a joint displacement of 1.5 mm was determined from the load-displacement curve. A ligament or pair of ligaments was then cut and the testing procedure repeated. Their contribution to restraining force was calculated as the percentage change in restraining force after the ligament was sectioned. Relative cross-sectional areas of the ligaments tested were measured at the level of the midcarpal joint.
Results— The collateral ligaments were the major contributors to the restraint of dorsal displacement ( P <.001). In all joints, the palmar intercarpal ligaments contributed a greater proportion than the palmar carpal ligament (PCL) ( P <.05). The mean percentage (±SEM) contributions to the restraint of dorsal displacement were 62.8 ± 3.4 for the collateral ligaments, 14.5 ±1.4 for the PCL, and 22.7 ± 2.2 for the palmar intercarpal ligaments. Mean cross-sectional area expressed as a percentage (±SEM) of the total ligamentous area were 9.0 ± 0.3 for the palmar intercarpal ligaments, 27.1 ± 3.0 for the PCL, and 63.8 ± 2.8 for the collateral ligaments.
Conclusions— Despite the small size of the palmar intercarpal ligaments, they play an important role in the restraint of dorsal displacement of the proximal row of carpal bones.
Clinical Relevance— Interpretation, as well as prevention and treatment of intercarpal ligament tearing requires an understanding of their function.     

A Preliminary Survey of the Public's Concepts of Amenity in British Forestry

The increasing recreational use of forests makes their appearanceof greater importance than ever. Varying, and often conflicting,opinions on forest amenity have been expressed by the forestryprofession and the public. In an attempt to quantify publicopinion, a postal questionnaire survey was conducted with regardto the desired appearance and permissible public access anduse of forest areas. The results were analysed statistically,and indicated a strong bias towards woodlands of natural appearance.There was a widespread demand for greater access into stateforests but for limited commercial developments. Afforestationwas generally acceptable, and it was considered that managementought to be a compromise between timber production and amenityconsiderations. In view of the Forestry Commission's commitmentto take account of amenity, it is urged that a definite policybased on the users' wishes be formulated and effected.     

The influence of sward species composition on the rate of organic matter decomposition in grassland soil

To examine the influence of different plant materials on the rate of organic matter (OM) decomposition in soil, respiration and N mineralization/immobilization were measured during incubation of a test soil to which the plant materials were added. Amendments consisted of sward material either from grassland plots with different amounts of OM accumulation, or material from plants associated with soils having markedly different OM contents. Evolution of CO₂ from the test soil plus herbage from an experimental plot showing OM accumulation was greater than that from the same soil amended with herbage from plots without accumulation. Apparently, grass species had no significant effect on OM turnover; differences in accumulation in grassland soils must be related to other environmental factors. Decomposition of young Calluna vulgaris was, however, slower than that of young grass material and in this case species could affect organic matter accumulation.     

Suppression of Sumatra disease symptoms in cloves treated with antibiotics

Repeated infusions of a mixture of oxytetracycline and streptomycin into the wood of initially symptomless clove trees exposed to natural infection by Sumatra disease resulted in a delay in symptom onset and slower rates of symptom development compared with untreated trees. The numbers of bacterially occluded vessels in root samples of treated trees were significantly fewer than those from controls. These results strongly support the hypothesis that a xylem-limited. Gram-negative bacterium, known to be consistently associated with Sumatra disease symptoms, is the causal agent. The productive life of treated trees was usefully extended but some phytotoxicity was observed, resulting in leaf scorching and stunted flower buds. In view of the high value of the crop, antibiotic therapy merits further investigation as a short-term control measure.     

Yield and nitrogen utilization by Lolium perenne and Trifolium repens on a limed stagnohumic-gley soil in a pot experiment

In a pot experiment the pH of a hill peaty soil was adjusted to cover the range 3.8 to 6.8 with Ca(OH)₂. Yield and N content of the harvested plant material was greatest at pH 6.8 in pots sown with only Lolium perenne , and greatest at soil pH 6.1 in pots sown with Trifolium repens and L. perenne. T. repens established only at soil pH between 4·3 and 6·1. A small reduction in sward yield and a large and highly significant decrease in total N recovered by the harvested material, which occurred with increase in soil pH from 3·8 to 4·3, was attributed to a combination of increased N immobilization in the soil microbial biomass and to the poor performance of both sown and self-propagating indigenous species around pH 4·3.