Comparative study on the characteristics of knitted fabrics made of vortex-spun viscose yarns

Murata vortex spinning system is based on the air jet spinning system. The vast majority of previous works deal with the properties of vortex spun (VS) yarn and the spinning system. In this study, we investigated knitted fabrics from VS yarn in comparison with fabrics from ring (RS), compact (CS) and open-end rotor (OES) spun yarns made from viscose. The effect of yarn spinning system on dimensional and physical properties of knitted fabrics was explained with specific attention to fabrics from VS yarn. Shrinkage of fabrics from VS yarn has the lowest at widthwise direction, while having the highest at lengthwise direction. It is shown that the order of fabric spirality and twist liveliness for yarns from different spinning systems are quite similar. However, relation between loop shape factor and angle of spirality is inconsistent. Angle of spirality of fabrics from VS yarn is higher than fabrics from OES yarn, but lower than that of others. The bursting strength of fabrics from VS yarn is lower than that of those from RS and CS yarns and higher than that of those from OES yarn. From this study, it is also evident that fabrics from VS yarn have the lowest pilling tendency and highest resistance to abrasion.     

The effect of twist liveliness on the woven fabric distortion

This paper deals with the grey fabric deformation during relaxation. It investigates the effect of twist direction and twist liveliness on the 2/2 twill weave woven fabric distortion, during relaxation This experimental work shows that twist liveliness increases the natural tendency of the twill weave woven fabric to skew. In addition when the twist direction of the warp and weft is opposite to each other the bias curling occurs too.     

The effects of operating parameters on the fabrication of polyacrylonitrile nanofibers in electro-centrifuge spinning

Introduced recently, electro centrifuge is a new method for nanofiber production. In the electro-centrifuge method, fibers are produced by the simultaneous use of electrical and centrifugal forces. In this research, the effective parameters in the production of PAN nanofibers diameter and the influence of each of them have been discussed. These parameters are voltage, rotation speed, flow rate of exiting solution from nozzle and viscosity of solution. Also the capability of fiber production by this method is compared with the conventional electrospinning system. Results show that a significant enhancement can be achieved by proper adjustments of the polymer solution viscosity, applied voltage, and rotational velocity in fiber production rate. To exemplify, in a PAN polymer solution, the increased production rate of electro centrifuge varied from 193 to 1200 percent, as compared with a similar electrospinning method in which the polymer concentration and applied voltage varied in a range of 13 to 16 wt% and 15 to 10 kV, respectively.     

The effect of different factors on the content of nitrate in some potato varieties

Summary The ability for nitrate accumulation in potato tubers as affected by mineral fertilisation (N, K₂O and MgO), genotype and the site of cultivation was studied in a three-year-long field experiment. Fertilisation with potassium chloride and potassium sulphate increased nitrate concentration in the tubers while additional magnesium fertilisation reduced nitrate concentration. Significant differences in nitrate concentrations were observed in potato tubers depending on genetic conditions as well as on the cultivation location (with the same soil and climatic conditions, varieties and tillage). The nitrate content decreased as the result of storage at 4 °C. Concentration of these ions in tubers of table and industrial potatoes did not exceed Acceptable Daily Intake level determined by WHO.     

The investigation of life cycle cost on the basis of functional diagnosis in Tha Ngon project in Laos

In recent years, the deterioration of irrigation facilities has been progressing in the countries of Southeast Asia, as well as Japan. Hence, it is vital to introduce the concept of stock management, which decreases their life cycle costs. Life cycle costs of each scenario that combined construction methods and timing of implementation were compared by using single curves degradation prediction model and the Markov chain model as method of degradation prediction based on the result of the functional diagnosis executed in Laos Tha Ngon project area. Scenarios were made from combined types of frequency of operation and maintenance (O&M) of facilities, which were low-frequency, medium-frequency and high-frequency, with types of quality of construction method, which were low-quality, medium-quality and high-quality. As a result, in case of Laos Tha Ngon, a scenario combined middle-frequency of O&M with middle-quality of construction method has become the lowest cost in the four scenarios. This process was shown as a method in stock management which attempts to maintain long life for irrigation facilities and contributes to efficient budget implementation through the reduction of the rehabilitation and the renewal of projects expense.     

The influence of genotype on the effects of impact damage on the accumulation of glycoalkaloids in potato tubers

Summary The effects of impact damage on the accumulation of glycoalkaloids in tubers were studied in a wide range of potato genotypes. Damage, caused by drop tests, resulted in increased glycoalkaloid levels, which sometimes exceeded the toxic limit of 20 mg/100 g fresh weight; there were large differences in levels between genotypes. When the total damage index was high, the severe damage types—shatter cracks and splits—were responsible for the initiation of glycoalkaloid synthesis in stressed tuber tissue, whereas the less severe damage types—bruises and black spot—were not. Genotypes which had the highest shatter crack indices often had the greatest increases in glycoalkaloids. The high correlation between the initial glycoalkaloid level and the increased level after damage showed that selection for low glycoalkaloid potato clones is important.

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Zusammenfassung Der Einfluss von Stossverletzungen auf die Glykoalkaloide in Knollen wurde an 18 bis 21 Sorten und Zuchtklonen untersucht. Die Knollen liess man von 150 cm H?he (1981) bzw. 100 cm H?he (1982) herabfallen, um Stossverletzungen unterschiedlicher Typen (Schwarzfleckigkeit, Quetschungen, Schlagrisse, Brüche) und unterschiedlicher St?rke hervorzurufen. Der Gehalt an Glykoalkaloiden (α-Solanin und α-Chaconin) wurde an unbehandelten und besch?digten Knollen bestimmt. In unbehandeltem Material wurden wechselnde Glykoalkaloidgehalte aufgefunden (Tab. 1). Die Falltests ergaben grosse Sorten-differenzen hinsichtlich der Verletzungsemp-findlichkeit. Eine Fallh?he von 150 cm verursachte hohe Indizes für die Gesamtbesch?digung (Tab. 2). Unter den einzelnen Besch?digungs-typen waren Brüche und Schlagrisse am h?ufigsten. Der Glykoalkaloidgehalt erh?hte sich signifikant in den Knollen mit Stossverletzungen, und in einer Sorte wurde die toxische Schwelle von 20 mg/100 g Frischgewicht überschritten (Tab. 1). Die Glykoalkaloidbildung war signifikant korrelliert mit dem Schwellenwert in unbehandelten Knollen. Sorten und Klone mit den h?chsten Schlagriss-Indizes zeigten die gr?ssten Zunahmen. Eine zweimalige Fallbehandlung ergab h?here Verletzungsindizes und die Glykoalkaloidgehalte stiegen weiter an. Die Werte schwankten dabei zwischen 4 und 53 mg Glykoalkaloid/100 g Frischgewicht. Drei Sorten/Klone überschritten 20 mg/100 g und drei andere waren nahe an der toxischen Schwelle. Eine Fallh?he von 100 cm bewirkte auff?llig niedrigen Anteile an Stossverletzungen (Tab. 3). Schwere Verletzungenstypen, z.B. Schlagrisse und Brüche, waren hier nicht so h?ufig als weniger schwere, wie Quetschungen und Schwarzfleckigkeit. Der Glykoalkaloidgehalt war verglichen mit demjenigen in unbehandelten Knollen nur geringfügig h?her (Tab. 1). Das Glykoalkaloidniveau der besch?digten Knollen war gut korrelliert mit dem ursprünglichen Niveau, es stand aber weder zum Gesamtindex der Stossverletzungen noch zum Index irgendeines besonderen Besch?digungstyps in Beziehung. Der Grund dafür lag vermutlich in der geringen Anzahl von Verletzungen, insbesondere in der geringen H?ufigkeit von Schlagrissen. Eine zweimalige Fallbehandlung erh?hte signifikant den Gesamtverletzungsindex und die H?ufigkeit der Quetschungen. Dabei ergab sich ein geringer Zuwachs an Glykoalkaloiden mit einer sortenbedingten Differenz von 2–20 mg/100 g Frischgewicht. Der Glykoalkaloidgehalt war jedoch nicht korrelliert mit dem Index der gesamten Stossverletzungen oder, vielleicht mit Ausnahme der Quetschungen, mit dem Index irgendeines besonderen Besch?digungstyps. Die Untersuchung zeigte, dass schwere Stossverletzungen eine Erh?hung des Glykoalkaloidgehaltes in Kartoffelknollen verursachen. Die Pflanzenzüchtung ist ein m?glicher Weg, um die Resistenz gegenüber mechanischen Besch?digungen zu erh?hen, wenngleich stets eine sorgf?ltige Behandlung notwendig ist, um die Besch?digungsh?ufigkeit in der Handelsware zu reduzieren. Die hohe Korrellation zwischen dem ursprünglichen Glykoalkaloidniveau und dem erh?hten Niveau nach der Besch?digungsinduktion zeigt, dass es wichtig ist, Kartoffelklone mit geringem Glykoalkaloidgehalt zu selektieren.

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Résumé L'influence des endommagements par impacts sur les glycoalcalo?des dans les tubercules a été étudiée sur 18–21 variétés et clones de sélection. Les différents types d'endommagements (noircissement interne, meurtrissures, cavernes et fissures) ainsi que leur gravité sont analysés après une chute des tubercules d'une hauteur de 150 et 100 cm, respectivement en 1981 et 1982. La teneur en glycoalcalo?des (α-solanine et α-chaconine) est déterminée dans les tubercules n'ayant subi aucun traitement et dans les tubercules endommagés. Une grande variété de teneurs en glycoalcalo?des est observée dans les tubercules non endommagés (tabl. 1). Les tests d'impacts ont montré des différences variétales importantes, quant à la sensibilité à l'endommagement. La hauteur de chute de 150 cm a causé des indices d'endommagements élevés (tabl. 2). Les fissures et les cavernes sont les types d'endommagements les plus fréquents. La teneur en glycoalcalo?des augmente de fa?on significative dans les tubercules endommagés et pour une variété, le seuil de toxicité de 20 mg/100 g de poids frais est dépassé (tabl. 1). La réponse dans la formation de glycoalcalo?des est correlée de fa?on significative à la teneur initiale, dans les tubercules non endommagés. Les variétés et clones qui présentaient le plus grand nombre de cavernes ont eu les augmentations les plus fortes. Les traitements comprenant deux chutes ont donné les indices d'endommagements les plus élevés et des teneurs en glycoalcalo?des encore plus importantes. Celles-ci variaient entre 4 et 53 mg/100 g de poids frais. Trois variétés/clones ont dépassé les 20 mg pour 100 g et trois autres étaient très proches de ce seuil de toxicité. La hauteur de chute de 100 cm a conduit à des niveaux d'endommagements beaucoup plus faibles (tabl. 3). Les types d'endommagements graves, c'est-à-dire les cavernes et les fissures, furent moins fréquents que les autres types d'endommagements moins graves: les meurtrissures et le noircissement interne. Il n'y eut qu'une légère augmentation des teneurs en glycoalcalo?des, comparée à celles des tubercules non endommagés (tabl. 1). Le niveau de glycoalcalo?des dans les tubercules endommagés est fortement correlé au niveau initial, mais n'est pas lié à l'indice total d'endommagements ni à l'indice d'un quelconque type d'endommagement. Ceci est probablement d? au faible niveau d'endommagement et notamment à la faible quantité de cavernes. Les traitements comprenant deux chutes ont donné un indice total d'endommagements plus élevé avec davantage de meurtrissures. La teneur en glycoalcalo?des a légèrement augementé, avec des différences variétales de 2–20 mg/100 g de poids frais. Toutefois, les glycoalcalo?des ne furent pas correlés à l'indice total ou à l'indice d'un des types d'endommagements, excepté peut être les meurtrissures. Cette recherche montre que les endommagements graves par impacts provoquent l'augmentation des teneurs en glycoalcalo?des dans les tubercules de pomme de terre. La sélection des variétés est un moyen pour augmenter la résistance des tubercules à l'endommagement, bien que des précautions dans les manutentions sont nécessaires pour réduire les fréquences d'impacts des pommes de terre de commercialisation. La forte corrélation entre le niveau initial de glycoalcalo?des et son augmentation après endommagement montre que la sélection des clones à faible teneur en glycoalcalo?des est importante.

     

The long-term effects on upland sheep production in the UK of a change to extensive management

Extensification (a reduction in fertilizer inputs and stocking rate of grassland) is seen as one way of increasing the conservation value and of reducing the environmental impact of upland sheep production in the UK, but little is known about the consequences of such a change. This study determines the changes in animal production over ten years following the introduction of four extensive grazing management strategies to perennial ryegrass/white clover pastures at two upland sites. Fertilizer‐free treatments were maintained with sward heights of: 4 cm (treatment 4/4U) or 8 cm (8/8U) during the whole of the grazing year, 4 cm during summer and 8 cm during autumn (4/8U) and 8 cm during summer and 4 cm during autumn (8/4U). A control treatment that received 140 kg N ha^?1 year^?1 was also maintained with a sward surface height of 4 cm (4/4F). Scottish Blackface sheep grazed all treatments. The 4/4F treatment carried the greatest number of animals (3746 grazing days ha^?1 year^?1); the 4/4U and the 8/8U treatments carried 0·73 and 0·43 of this number respectively. The number on the 4/8U treatment was similar to that on the 4/4U while the 8/4U treatment carried 1·41 of that on the 8/8U treatment (0·61 of 4/4F). Mean individual animal performance was greatest on the 8 cm swards and tended to be lowest on the 4/4F treatment. However, the 4/4F treatment produced the greatest live weight of lamb (623 kg ha^?1 year^?1) with the 4/4U producing 0·77, and the 8/8U producing 0·55, of this amount. Although there was year‐to‐year variation in agricultural output, it was concluded that the lower levels of sheep production that result from a change to extensive systems of grazing management can be maintained for at least 10 years.     

The effects of extrusion on the content and properties of dietary fibre components in various barley cultivars

Wholemeal flour from five Czech spring barley materials was processed in a single-screw extruder at 130 °C, addition of 20% water and a screw speed of 220 rpm. Two barleys (AF Cesar, AF Lucius) were hulless cultivars with a standard starch composition, while three barleys (KM 2624, KM 2460-1, KM 2460-2) were hulled waxy lines. The effect of extrusion on content of different dietary fibre fractions was determined. Also the changes of the molar mass of β-glucan were studied. Regardless of the barley genotype (standard starch or waxy), the extrusion had no significant effect on arabinoxylan content. A significantly higher beta-glucan and soluble dietary fibre content in barley cultivars with standard starch composition was observed after extrusion. The content of insoluble dietary fibre decreased significantly in all extruded flours. The molar mass of water-extractable beta-glucan increased independently of the barley variety after extrusion. But the increase in beta-glucan extractability due to extrusion was not observed.     

细柱五加果实提取物对四氯化碳致小鼠急性肝损伤的保护作用

目的研究细柱五加果实乙醇提取物对四氯化碳致小鼠急性肝损伤的保护作用。方法将60只小鼠随机分成细柱五加果实的高、中、低剂量组以及阳性对照组、模型对照组、空白对照组共6组。6组小鼠ig给药20 mL/(kg.d)。连续14 d。第14 d给药1 h后,除空白对照组外,其余各组均ip 0.1%CCl4 0.2 mL/20g。所有小鼠在ip CCl4 16 h后采用眼球取血并脱颈椎处死。然后离心取血清,剖腹取肝。分别将各组肝脏取出0.1 g,加0.9 mL生理盐水进行匀浆。检测血清中丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转氨酶(AST)活性及肝匀浆中丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性的变化。结果与模型对照组相比,不同剂量的细柱五加果实乙醇提取物均能显著降低血清中丙氨酸氨基转移酶(ALT)、天门冬氨酸氨基转氨酶(AST)的活性及肝组织中丙二醛(MDA)的含量,提高超氧化物歧化酶(SOD)的活性。结论细柱五加果实乙醇提取物对四氯化碳致小鼠的急性肝损伤有保护作用。     

The effects of high-concentrate diets and pasture on the concentration of conjugated linoleic acid in beef muscle and subcutaneous fat

Abstract In view of the evidence indicating several potential benefits of high intakes of conjugated linoleic acid (CLA) on human health, an experiment was conducted to examine the effects of the diet of beef cattle on the total CLA concentration in muscle and subcutaneous fat. High‐concentrate [steers consumed 515 g concentrates and 485 g grass silage kg^?1 dry matter (DM) for 8 weeks followed by 887 g concentrates and 113 g grass silage kg^?1 DM for 14 weeks until slaughter] and high‐forage (steers consumed 803 g grass silage and 197 g concentrates kg^?1 for 8 weeks followed by grass silage only for 10 weeks and then grazed perennial ryegrass‐based pasture for 23 weeks until slaughter) treatments were imposed on 48 steers, which were crosses of continental beef breeds (initially 414 kg live weight) The concentrates were based on barley, extracted soyabean meal, molassed sugarbeet pulp and maize meal. The silages were of medium to low digestibility and contained 117–137 g crude protein kg^?1 DM and 83–158 g ammonia‐N kg^?1 total N. The pasture was of high quality and contained 168 g crude protein, 234 g acid‐detergent fibre and 222 g water‐soluble carbohydrate kg^?1 DM. Samples of muscle were taken post slaughter from the m. semimembranosus, m. gluteobiceps, m. longissimus and m. deltoideous muscles, and subcutaneous fat was taken from over the m. longissimus. Concentrations of total CLA in the tissues were for the high‐concentrate and high‐forage treatments, respectively (mg 100 g^?1 fresh tissue), m. gluteobiceps 18 and 47 (s.e. 3·5); m. semimembranosus 9 and 20 (s.e. 1·6); m. longissimus 15 and 35 (s.e. 3·2), m. deltoideous 20 and 59 (s.e. 4·3); subcutaneous fat 584 and 1975 (s.e. 138·7). It is concluded that muscle and subcutaneous fat tissue from grass‐fed cattle contained three times as much CLA as those from concentrate‐fed cattle, and that the consumption of beef from grass‐fed cattle should be effective in increasing the intake of CLA by humans.     

CRMS诱导水稻雄性不育的研究：Ⅱ．CRMS诱导水稻雄性不育的生理效应

 于水稻花粉母细胞减数分裂期每丛施用20～30 mg CRMS(有效成分)，可诱导水稻高度雄性不育。CRMS诱导水稻雄性不育与CRMS诱导花粉畸形，败育有关，原因是施用CRMS，缩短花药的长度和花药中的花粉数，降低花粉粒充实度和花粉发芽力，降低花药呼吸作用，干扰蛋白质和淀粉的积累，抑制花药发育与花粉活力。     

The USDA trypsin inhibitor study. IV. The chronic effects of soy flour and soy protein isolate on the pancreas in rats after two years

In two year feeding trials, histologic changes in the pancreas of the Wistar rat were evaluated after chronic dietary exposure to raw and heated, dehulled, defatted soy flour and soy protein isolates which provided a range of trypsin inhibitor (TI) concentrations from 93 to 1271 mg/100 g diet. Also investigated was the nutritional interaction of level of dietary protein with the development of pancreatic pathology. Graded levels of TI were achieved from mixtures of raw and heated soy flour or protein isolate. Dietary protein levels were 10%, 20%, and 30%; the two higher levels obtained in some diets through casein supplementation. A total of 26 diets, including casein controls, were fed to groups of 40 male rats. Growth rates with these diets were commensurate with protein quality and level. Mortality rates tended to be slightly greater in the higher protein diets, and rats fed only raw soy as a source of protein survived well.Two lesions, nodular hyperplasia (NH) and acinar adenoma (AA) constituted the major pathological findings in the pancreas, and the incidence rates of both were positively associated with the concentration of dietary TI. The incidences of pancreatic NH and AA compared to those of the corresponding casein control were significantly elevated in rats fed heated soy flour supplying 10% protein and the lowest level of TI investigated (93 mg/100 g diet). At low levels of TI (215 mg/100 g diet), supplementation by casein to raise the concentration of protein from 10% to 20% and 30% reduced the frequency of NH and AA. When the dose-response data for NH and AA was linearized by plotting the probit of percent incidence against log of TI concentration per gram of dietary protein, the response to soy flour and soy protein isolate was not significantly different. Numerous lesions commonly found in the aging rat were diagnosed, and modulation of their rate of occurrence by nutritional factors associated with the diets was apparent in some instances.Reference to a company and/or product named by the Department is only for purposes of information and does not imply approval or recommendation of the product to the exclusion of others which may also be suitable.     

The effects of temperature and light on the symptom expression and viroid concentration in tomato of a severe strain of potato spindle tuber viroid

Summary Indexing on tomato of dilution series prepared from young tomato seedlings infected with a severe strain of potato spindle tuber viroid (originally isolated from wild tuber-bearingSolanum and later used for cross-protection tests to detect mild strains) indicated that viroid concentration rose more quickly in tomato at 31°C than at 23°C at various light intensities. At either temperature, low light intensity for 17–18 hours each day did not critically limit synthesis. At 31°C, symptoms which were otherwise severe by 2 weeks were delayed and less obvious under low light. At 23°C, symptoms were delayed at low or higher light intensity and did not appear if the temperature was allowed to fall to 15°C at night. Leaf vein necrosis which was favoured by moderate rather than by high temperature, possibly was similar to necrosis induced by viruses or other infection.

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Zusammenfassung Für die Aufgabe, Kartoffelpflanzen und andere knollentragende Arten vonSolanum auf Befall mit Kartoffel-Spindelknollenviroid (PSTV) zu testen (Vorkommen in handelsüblichen Kartoffelposten in Grossbritannien nicht bekannt), wurde ein auffallender, ursprünglich ausSolanum commersonii Dun. isolierter PSTV-Stamm für einen Pr?munit?tstest an Tomatenpflanzen verwendet in der Absicht, einen durch milde St?mme angebotenen Schutz zu entdecken. Die Symptome variieren je nach den Wachstumsbedingungen. Die Tomatenpflanzen mussten gut ern?hrt werden. Bei der Sorte Sheyenne, inokuliert im 2–3-Blattstadium und in einer Wachstumskammer bei 31°C gehalten, zeigen sich nach 2 Wochen schwere Symptome, wenn genügend Licht vorhanden ist. (Volles Licht: 55 W m⁻² oder 550 μE m⁻²s⁻¹ photosynthetisch aktive Strahlung (PAR) w?hrend 17–18 Stunden t?glich: Tabelle 1.) Die Symptome sind: Rauhbl?ttrigkeit, Epinastie und Chlorose am Wipfel der Pflanze und, charakteristischerweise, Kümmerwuchs. Bei einer niedrigen Lichtintensit?t von 25 W m⁻² PAR wird die Symptomausbildung bei 31 °C verz?gert, und anstelle des Kümmerwuchses wird allgemeine Chlorose sichtbar. Die hohe Temperatur begünstigt die Nekrose an Blattadern nicht. Ein m?ssige Temperatur von 23°C bei niedriger oder h?herer Lichtgabe bringt sp?tere und weniger augenf?llige Symptome (Tabellen 1 und 3), neigt aber zur F?rderung von Nekrosen. Eine Nachtabsenkung von 23°C auf 15°C w?hrend 24 Tagen verhütet die Ausbildung von Symptomen an Pflanzen sowohl bei hoher wie bei niedriger Lichtintensit?t (Tabelle 1). Bringt man Pflanzen, die anf?nglich bei mittlerer oder hoher Temperatur und gutem Licht gewachsen waren, in ein Verfahren mit wenig Licht und mittlerer Temperatur und-wie in Tabelle 2 zusammengefasst-zu 23°C Tag-und 15°C Nachttemperatur, so erh?lt man bei gut infizierten Pflanzen starke Nekrosen. Eine erfolgreiche Infektion scheint bei 23°C mehr Zeit zu beanspruchen als bei h?herer Temperatur (Tabelle 2). Messungen der Infektiosit?t von Homogenaten der ganzen Pflanzen, dargestellt als die maximale Verdünnung jedes Homogenats, die mindestens bei 2 von 3 Tomatenpflanzen (Tabelle 3) Symptome hervorruft, zeigen, dass die Viroid-Konzentration bei 31°C rasch ansteigt. Dies kann mit dem frühen Erscheinen von Symptomen, sobald genügend Licht vorhanden ist, in Zusammenhang gebracht werden. Eine niedrige und eine mittlere Lichtintensit?t (35 W m⁻²) bewirken keine signifikante Reduktion viroider Konzentrationen bei 31°C, obwohl sie die Symptomausbildung verz?gern. Die Konzentration steigt bei 23°C oder 31°C über einen Zeitraum von 2–3 Wochen weiter an, auch wenn die Lichtintensit?t w?hrend 17–18 Stunden t?glich nur gerade genügt, das Wachstum zu erhalten (Tabelle 3). In der Diskussion wird darauf hingewiesen, dass ein niedrigerer Lichtstand w?hrend 17–18 Stunden t?glich die Synthese nicht entscheidend begrenzt, w?hrend l?ngere Lichtperioden und h?here Lichtintensit?t eine erh?hte Viroidsynthese ergeben k?nnten. Es wird auch vermutet, dass die temperaturabh?ngige Nekrose, die durch dieses Viroid induziert wird, ?hnlich sein dürfte wie die Nekrose, die durch Viren oder eine andere Infektion ausgel?st wird. Nicht ver?ffentlichte. Beobachtungen von Fluoreszenz in UV-Licht rund um die L?sionen inScopolia sinensis Hemsl., die mit PSTV befallen sind, werden zur Stützung dieser Ansicht angeführt. Als Teil eines neuen Verfahrens zum Nachweis von PSTV wurden die Tomatensorten Sheyenne und Ailsa Craig verwendet, um Viroid-Konzentrationen aufzubauen.

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Résumé Afin de sélectionner des pommes de terre et d’autres espèces deSolanum ‘tubérifères’ résistantes au viro?de du ‘Spindle tuber’ (PSTV) (inconnu au Royaume Uni), on a utilisé une souche différente de PSTV isolée à partir deSolanum commersonii Dun. pour surinfecter des plantes de tomate, dans un test de protection croisée de manière à détecter l’effet de protection apporté par des souches peu virulentes. Les sympt?mes varient avec les conditions-de culture, et les plantes de tomate doivent recevoir une alimentation correcte. Pour la variété Sheyenne, inoculée au stade 2–3 feuilles et maintenue à 31°C, des sympt?mes sévères apparaissent en 2 semaines si la lumière est suffisante (une forte luminosité correspond à une radiation photosynthétiquement active (PAR), de 55 W m⁻² ou à 550 μE m⁻²s⁻¹, pendant 17 à 18 h par jour: tab. 1.) Les sympt?mes correspondent à une rugosité, une épinastie et une chlorose au sommet de la plante, on a également un rabougrissement caractéristique. Une faible intensité lumineuse de 25W m⁻² PAR, retarde l’ expression des sympt?mes à 31°C, et le rabougrissement est contrecarré par un étiolement. La haute température ne favorise pas la nécrose des nervures. Une température modérée de 23°C, à éclairement faible ou plus élevé donne des sympt?mes plus tardifs et moins évidents (tab. 1 et 3), mais ces facteurs tendent à favoriser la nécrose. Une chute de température à 15°C, chaque nuit, empêche l’expression des sympt?mes pour des plantes placées à 23°C pendant 24 jours, et soumises à une intensité lumineuse élevée ou faible (tab. 1). Des plantes initialement cultivées à des températures modérées ou élevées, en luminosité correcte, et soumises ensuite à un régime de faible luminosité et de température modérée, respectivement 23°C le jour et 15 °C la nuit, extériorisent des nécroses sévères si la contamination a été réussie (expérimentations qui ont été résumées dans le tableau 2). L’infection semble prendre plus de temps pour s’installer à 23°C, qu’à température plus élevée (tableau 2). Des mesures du pouvoir infectieux d’homogenats de plantes entières, considérées comme étant la dilution maximale de chaque homogenat infectieux sur au moins 2/3 des plantes de tomate (tab. 3), indiquent que la concentration en viro?de augmente rapidement à 31 °C. Cela peut être corrélé avec l’apparition précoce des sympt?mes chaque fois que la lumière est suffisante. Une faible intensité lumineuse et une intensité lumineuse moyenne (35 W m⁻²) bien que cela retarde l’expression du sympt?me, ne semble pas réduire significativement les concentrations en viro?de à 31°C. La concentration continue à augmenter durant une période de 2 à 3 semaines à 23°C ou 31°C, même quand l’intensité lumineuse de 17 à 18 h chaque jour est juste capable de maintenir la croissance (tableau 3). Dans la discussion, les auteurs émettent l’hypothèse que les périodes d’éclairement plus longueus et l’intensité lumineuse plus élevée peuvent se traduire par une augmentation de la synthèse viro?de; un éclairement faible pendant 17 à 18 h chaque jour ne limitera pas de manière critique la synthèse. On suppose que les nécroses dépendant de la température et induites par le viro?de, peuvent être identiques aux nécroses induites par les virus ou par d’autre infection. Des observations non publiées sur la fluorescence en lumière UV, autour des lésions surScopolia sinensis Hemsl. contaminé par PSTV, sont citées pour défendre ce point de vue. Dans le cadre d’un nouveau procédé de détection du PSTV, les variétés de tomate Sheyenne et Ailsa Craig ont été utilisées afin d’augmenter la concentration en viro?de.

     

The effects of lactic acid bacteria strains isolated from various substrates on the fermentation quality of common vetch (Vicia sativa L.) in Tibet

Eight lactic acid bacteria (LAB) strains isolated from five naturally fermented silages of different ensilage materials on the Tibetan Plateau were characterized, and their effects on the silage quality of common vetch (Vicia sativa L.) were studied. These LAB isolates were evaluated using morphological, physiological and biochemical tests. The eight isolated strains and one commercial inoculant (Lactobacillus plantarum MTD‐1) were subsequently added to common vetch for ensiling 60 days. All the isolated strains (LW4, M1, WG27, O30, I2, LCG3, LCG9, CG35) could grow normally at 5–20°C, pH 3.5–6.0 and NaCl (3.0%, 6.5%), and they were identified as Lactobacillus plantarum and Pediococcus pentosaceus by sequencing 16S rDNA. All the LAB inoculants improved the silage quality of common vetch, indicated by significantly (p < .05) higher lactic acid (LA) contents and ratios of lactic acid to acetic acid (LA/AA), and significantly (p < .05) lower pH and ammonia nitrogen (NH₃–N) contents. Strain LCG3 performed best among all LAB inoculants, indicated by the highest (p < .05) LA content and ratio of LA/AA, and the lowest (p < .05) pH and NH₃–N content. Strain LCG3 is recommended as starter culture for common vetch silage.     

The effects of rate and timing of application of fertilizer nitrogen in late summer on herbage mass and chemical composition of perennial ryegrass swards over the winter period in Northern Ireland

A small‐plot experiment was carried out in Northern Ireland on a predominantly perennial ryegrass sward over the period July 1993 to March 1994 to investigate the effect of timing and rate of fertilizer nitrogen (N) application on herbage mass and its chemical composition over the winter period. Eighty treatment combinations, involving four N fertilizer application dates (28 July, 9 and 30 August and 20 September 1993), four rates of N fertilizer (0, 30, 60 and 90 kg N ha^?1) and five harvest dates (1 October, 1 November, 1 December 1993, 1 February and 1 March 1994), were replicated three times in a randomized block design experiment. N application increased herbage mass at each of the harvest dates, but in general there was a decrease in response to N with increasing rate of N and delay in time of application. Mean responses to N applications were 13·0, 11·5 and 9·5 kg DM kg^?1 N at 30, 60 and 90 kg N ha^?1 respectively. Delaying N application, which also reduced the length of the period of growth, reduced the mean response to N fertilizer from 14·3 to 7·4 kg DM kg^?1 N for N applied on 28 July and 20 September respectively. Increasing rate of N application increased the N concentration and reduced the dry‐matter (DM) content and water‐soluble carbohydrate (WSC) concentration of the herbage but had little effect on the acid‐detergent fibre (ADF) concentration. Delaying N application increased N concentration and reduced DM content of the herbage. The effect of date of N application on WSC concentration varied between harvests. A decrease in herbage mass occurred from November onwards which was associated with a decrease in the proportion of live leaf and stem material and an increase in the proportion of dead material in the sward. It is concluded that there is considerable potential to increase the herbage mass available for autumn/early winter grazing by applying up to 60 kg N ha^?1 in early September.     

The effects of nitrogen uptake before and after heading on grain protein content and the occurrence of basal- and back-white grains in rice (Oryza sativa L.)

Chalky rice (Oryza sativa L.) grains are induced by high temperature during the grain-filling period. Plant nitrogen status also affects the occurrence of basal- and back-white grains (BBWG). The objective of this study was to elucidate the relations between nitrogen availability per spikelet during the grain-filling period (N_GF) and each of the percentage of BBWG and grain protein content (GPC). We further compared the effect of the components of N_GF determined before heading (N_BH) and after heading (N_AH) on BBWG and GPC. We grew the rice cultivar ‘Koshihikari’ in pots in 2012 and 2013, and top-dressed nitrogen at the panicle formation and heading stages, under two (2012) or three (2013) temperature regimes during the grain-filling period. GPC was explained well by N_GF, but BBWG was not. BBWG was best explained in a multiple-regression equation by mean air temperature after heading and by N_BH and N_AH. The partial correlation coefficients for N_BH were 1.6 and 3.0 times those for N_AH in 2012 and 2013, respectively. On the other hand, in a multiple-regression equation for GPC, the partial correlation coefficients for N_BH were 0.91 and 0.71 times those for N_AH in 2012 and 2013, respectively. These results suggest that rice grains are most sensitive to plant nitrogen status before heading for BBWG but after heading for GPC, and that there is an optimal timing for nitrogen top-dressing that would maximize the reduction in BBWG per unit increment of GPC.     

The effects of nitrogen rate and the ratio of NO3:NH4 on Bemisia tabaci populations in hydroponic tomato crops

Nitrogen fertilization is one of the factors that influences Bemisia tabaci (Gennadius) population density. The aim of this study was to determine the effects of three N application rates (75, 205 and 335 mg/l) and three ratios of NO₃⁻:NH₄⁺ ions (92:8, 75:25 and 55:45) in standard nutrient solution (205 mg/l N) on the population density of B. tabaci. The experiments were conducted on spring-summer hydroponic crops of tomato. The effect of plant stratum on the whitefly population was also determined. The aggregation of B. tabaci adults as well as their oviposition rate was higher at 205 and 335 mg/l N than on plants grown at 75 mg/l N. By the end of the experiment (60 d after infestation), the number of nymphs on plants at 205 mg/l N was higher than on plants at 75 mg/l N. The number of pupae was lowest on plants supplied with 75 mg/l N. An increase in NH₄⁺ percentage in standard nutrient solution (from 25% to 45% of the total N) reduced adult population density and oviposition rate. The density of nymphs and pupae, at 60 d after infestation, was lower on the tomato plants grown at 75:25 and 55:45 NO₃⁻:NH₄⁺ ratios compared to the 92:8 ratio. The 75:25 and 55:45 NO₃⁻:NH₄⁺ ratios resulted in a higher incidence of blossom-end rot of tomato fruit, with a lower incidence of disorder at 75:25 than at the 55:45 ratio. Plant stratum influenced adult whitefly distribution in two years of the study. Middle stratum leaves were more attractive to adults in both years. The results demonstrate the effects of N fertilization (N rate and the ratio of NO₃⁻:NH₄⁺) and plant stratum on B. tabaci population density.