A RAPID BIOASSAY FOR PEBC AND ITS APPLICATION IN VOLATILIZATION AND ADSORPTION STUDIES

Summary. A rapid bioassay for PEBC ( S -propyl- N -butyl- N -ethylthiolcarbamate) has been developed, based on the measurement of shoot elongation of oat seedlings in Petri dishes in a nearly vertical position. Results are obtained after 48 hr.
The bioassay was used to study the relationship between soil moisture and volatilization and adsorption of PEBC. When PEBC was applied to air-dry soil, no appreciable loss of activity occurred even after 36 days of exposure to a continuous air-flow. The residual activity of PEBC applied to soils of various moisture contents appears to be related to the initial moisture level. A substantial amount of the compound was adsorbed by air-dry soil after an exposure of 24 hr to vapours of PEBC. The amount of PEBC adsorbed from the vapour phase after 24 or 72 hr appears also to be related to the moisture content of the soil.
Un essai biologique rapide pour U PEBC et son utilisation dans l'étude dt la volatilisation et de l'adiorption du produit     

VARIATION IN BIOASSAY ATTRIBUTES AS QUANTITATIVE INDICES OE PICLORAM IN SOILS*

Summary. Symptom ratings were more effective than fresh weights or oven-dry weights of field beans or sunflowers to quantify nanogramme quantities of picloram in river sand. Fresh weights, dry weights or symptom ratings of soybeans effectively quantified nanogramme quantities of picloram in river sand or sandy clay loam. From 92 to 97% of the variation in bioassay reaction was attributed to variation in picloram concentration with the species studied, except cucumber, for which the functional relationship log concentration versus symptom rating was developed. Results from gas-liquid chromatographic analyses and the sensitive bioassay methods were closely correlated, but GLC demonstrated less inherent variability than the bioassay methods. By utilizing the proper functional relationship and indicator variable, regression analyses of bioassay reaction were used to determine picloram residues of 0–250 ng/g soil on a statistical basis. La variation des reactions biologiques considée comme un indice quantitatif du piclorame dans les sols Résumé. L'évaluation des réactions visiblcs a été plus efficace que la mesure des poids frais ou des poids sees de haricots ou de tournesols pour déceler des quantitfe de piclorame de l'ordre du nanogramme dans un sable de riviére. Les poids frais, les poids sees ou l'évaluation des réactions du soja ont été efficacement employés pour déceler des quantités de piclorame de l'ordre du nanogramme dans un sable de riviére ou un limon silicoargilcux. La variation des réactions observées dans les essais biologiques a été attributée dans une proportion de 92 à 97%à la variation de la concentration du piclorame selon les espéces étudiées, le concombre excepté; pour ces variations la fonction des relations entre le log de la concentration et l'éaluation des syinptômes a (étéétablie. Les résultats des analyses par chromatographic gaz-liquide et ceux des méthodes sensibles des essais biologiques se sont révélés en étroitc corrélation, mais la chromatographie gaz-liquiide a montré moins de variabilité propre que les méthodes biologiques. En utilisant la fonction appropriée et la variable indicatrice convenables, l'analyse de regression des reactions biologiques a été employée pour la determination, sur des bases statistiques, de réidus de piclorame entre 0 et 250 ng par gramme de sol. Veränderung von Eigenschaften im Biotest als quantitative Indices von Picloram im Boden Zusammenfassung. Die Bewertung von Symptomen erwies sich als besser als die Ermittlung von Frisch- oder Trockenmasse von Feldbohnen oder Sonnenblumen, um Nanogrammquantitäten von Picloram in Flussand zu bestimmen. Frisch-, Trockengewichte und Symptombewertung von Sojabohnen gestatteten eine effektive Bestimmung von Picloram im Nanogranimbereich in Flussand und sandigem Lehm. Die bei der Biotestreaktion aufgelretenen Schwankungen liessen sich bei den untersuchten Arlen zu 92 bis 97% auf die unterschiedliche Konzentration von Picloram zurückführen, mit Ausnahme der Gurke, für die eine Beziehung zwischen Symptombewertung und Logarithmus der Konzentration ausgcarbeitet wurde. Die Ergebnisse der gaschromatographisdien Analyse und der empfindlichen Biotests waren gut korreliert, die methodischen Schwankungen bei der Gas chromatographic geringer als bei den Biotests. Unter Verwendung der jeweiligen funktionalen Beziehung und der Indikatorvariablen konnten mit Hilfe der Regressionsanalyse der Biotestreaktion Picloramrückstände von 0–250 ng/g Boden auf statistischer Grundlage bestimmt werden.     

用PhastSystem电泳仪快速鉴定根结线虫种类

 应用瑞典Pharmacia Biotech.公司开发的全自动快速水平电泳仪(PhastSystem)进行酯酶和苹果酸脱氢酶电泳,对云南省烟草和观赏植物一串红上的根结线虫进行快速鉴定,得出4种根结线虫:花生根结线虫(Meloidogyne arenaria)、爪哇根结线虫(M.javanica)、南方根结线虫(M.incognita)和北方根结线虫(M.hapla)。文章提供电泳方法,认为PhastSystem电泳仪是根结线虫种类快速鉴定的理想设备。     

OCCURRENCE AND PERSISTENCE OF PICLORAM IN GRASSLAND WATER SOURCES

Summary. At 2 weeks following application, concentrations of picloram in surface runoff water collected adjacent to a South Texas grassland treated with 1·1 kg/ha ranged from 0·055 to 0·184 ppm as detected by gas chromatography. Picloram in surface runoff water diminished with time and amount of rainfall as a decay function. Picloram was not detectable in a flowing stream 0·8 km below a 32-ha area treated with 1·1 kg/ha. Residual picloram was not detected in domestic water wells at any time up to 2 years following treatment of adjacent areas with 1·1 kg/ha.
Dissipation of picloram from treated livestock-watering ponds was concentration-dependent, with the final losses resulting largely from dilution. Initial loss rates in the ponds ranged from 14 to 18%/day but decreased to less than 1%/day at 100 days following treatment. After 100 days, when the concentrations were less than 0·005 ppm, the primary changes in picloram content appeared to be due to dilution from rainfall or to concentration by runoff from adjacent treated areas.     

THE SELECTIVE ACTION OF PICLORAM IN RED MAPLE AND WHITE ASH

Summary. White ash ( Fraxinus americana L. ) trees, 2 years of age, treated continuously with 10 ppm picloram (4-amino-3,5,6-trichloropicolinic acid) in nutrient culture were only slightly injured after 4 weeks whereas red maple ( Acer rubrum L.) trees were killed after only 2 weeks treatment.
When the roots were exposed to 10 ppm ¹⁴C-picloram, the rate of root uptake, acropetal translocation in the stem, and accumulation in the leaves was much lower in the susceptible red maple than in the tolerant white ash. The foliar penetration and translocation of ¹⁴C-picloram applied to the leaves was very slight but similar in both species. Although a radiolabelled picloram metabolite was isolated from plant extracts, it was formed at equal rates in both species.
It was concluded that the tolerance of white ash was not related to lower rates of picloram uptake or faster rates of picloram detoxication. It was postulated that the high susceptibility of red maple was due to a blockage of the xylem by picloram which caused death by a dessication of the leaves and upper stems.
Action sélective du piclorame sur Fraxinus amerieana L. et Acer rubrum L.     

生测法测定甲草胺在土壤中的残留量

根据甲草胺对敏感植物的幼根或幼茎有抑制作用的原理,采用培养皿土培方法,通过测量发芽种子的根、茎长度来测定甲草胺在土壤中的残留量。实验室筛选试验表明,豌豆、黄瓜幼根及燕麦、小麦幼茎是测定甲草胺在土壤中残留量的敏感试材。豌豆及黄瓜的根部对甲草胺的敏感浓度线性范围较宽,为0.1—8.0微克/克土,IC_(50)(在草甸黑土中抑制根长50％所需要的甲草胺浓度)为3.23ppm±0.20及2.3ppm±0.16;燕麦及小麦茎部的敏感范围较窄,为0.5—5.0微克/克土,IC_(50)为1.3 ppm±0.10及2.8 ppm±0.15。用豌豆根生测法测定甲草胺在田间土壤中的消解动态表明,甲草胺在花生田草甸黑土中降解较快,半衰期为3天左右,其结果与气相色谱法接近。     

鳞翅目昆虫血细胞鉴定与分离纯化的几种方法

昆虫的细胞免疫包括吞噬作用和包囊作用,要分析哪些血细胞参与其中的作用,就必须能准确鉴定血细胞的种类并将其予以分离、纯化。本文就鳞翅目Lepidoptera昆虫血细胞的鉴定与分离纯化的几种方法进行了简单的介绍。     

利用BIOLOG鉴定系统快速鉴定菜豆萎蔫病菌的研究

 本研究利用美国Biolog公司生产的MicroStation^TM V3.5系统对我国一类危险性病害菜豆萎蔫病菌及其相关菌进行了快速鉴定研究。研究结果表明,来自不同国家和寄主的24株菜豆萎蔫病菌及其相关致病变种,23株准确鉴定至种水平,其中13株鉴定至致病变种水平,种水平的鉴定准确率为95.8%,另外1株至属水平。同时2株苜蓿萎蔫病菌和2株番茄溃疡病菌均鉴定至致病变种水平。经聚类分析研究,结果支持了对格兰氏阳性植病细菌在属、种水平的分类。本研究是首次使用该系统对格兰氏阳性植病细菌进行鉴定研究,试验证明Biolog鉴定系统用于快速鉴定菜豆萎蔫病菌是一个很有用的工具,且由于其标准化程度高、快速准确,符合我国口岸植物检疫的要求。     

棉铃虫作供试虫的Bt毒力生物测定感染饲料的研究

研究表明,酵母粉、黄豆粉和维生素C是棉铃虫生长发育的必需成分;仅用醋酸即可达到防腐的目的。本研究确定生物测定感染饲料配方为:黄豆粉7g、酵母粉4g、维生素CO.5g、36％醋酸1.25ml、琼脂1.5g,水100ml.醋酸用量占饲料重量的1～1.5％为宜。     

杀虫双水剂对稻田食虫瘤胸蛛和拟水狼蛛的影响

本文在室内和稻田研究了１８％杀虫双水剂对稻田蜘蛛优势种食虫瘤胸蛛和拟水狼蛛的毒杀作用。时间－死亡率曲线表明，食虫瘤胸蛛死亡高峰出现在药后３－６天间，拟水狼蛛死亡率曲线相对平缓，两类蜘蛛主要死亡时期均在药后１０天内；测定用药后１０天的致死中浓度，食虫瘤胞蛛为３６６．１０ｍｇ／ｋｇ（１９９３年）和５３８．５６ｍｇ／ｋｇ（１９９４年）拟水狼蛛为３４０．７４ｍｇ／ｋｇ（１９９３年）。田间试验也以应药后７天     

苏云金杆菌制剂标准化的程序和方法

本文对以小菜蛾为供试虫,测定苏云金杆菌制剂标准化的程序和方法进行了详细描述。按此程序,以美国标准品HD-1-S-1980作对照,对中国标准品CS5ab—87进行效价标定。17次生物测定的平均效价为8633±915IU/mg,变异系数10.6％。表明使用该生物测定程序和方法测定的结果重复性好,易于推广应用。     

小麦抗秆黑粉病快速鉴定方法研究

 小麦秆黑粉病近年在我国北方一些地区严重发生,引人注目。利用抗病品种防治该病最经济有效,但为鉴定品种抗病性创造带菌均匀的土壤条件,需大量要菌粉,而且鉴定周期很长;本研究为鉴定抗病性提供了快速方法。     

NOTE ON THE BIOASSAY OF CHLORPROPHAM IN SOIL

Summary. A method for the bioassay of chlorpropham in soil from field plots is described which involves the preparation of mixtures of treated soil with untreated soil and the determination of the dilution required to produce 50% inhibition of primary root growth in buckwheat ( Fagopyrum esculentum Moench). Using this method, it was found that the period required for 90% disappearance of chlorpropham from a sandy foam ranged from 3 to 14 weeks, according to the prevailing temperature and soil moisture conditions. When applications of 1 and 2 lb/ac were compared, the percentages of chlorpropham remaining at any one time were similar.
Dosage biologique du chlorpropham dans le sol     

THE EFFECTS OF PICLORAM AND 2,4-D ON PLANT CELL MEMBRANES

Summary. The herbicide Tordon 50D (picloram + 2,4–D) caused severe shrinkage of the protoplasts of all cells of Pinus radiata needle segments within 24 h of treatment. Measurements of the resistance of these tissues to low-frequency and to high-frequency electrical currents showed a loss in the integrity of the plasmalemma within 4–8 h of treatment. Tordon 22K (picloram) had no such effects. The results with Tordon 50D could be attributed solely to the 2,4-D content.
Both Tordon 50D and Tordon 22K disrupted chloroplast structure in leaf discs, and the integrity of cell membranes in stem tips, of Eucalyptus viminalis.     

飞虱虫疫霉的培养贮存和生测试验

飞虱虫疫霉是水稻褐飞虱及其它飞虱、叶蝉的寄生性天敌。在我国南方稻田分布很广,每年9月下旬至11月上旬可造成害虫流行疫病,有的地区寄生率高达70—80％.本文报道该菌的人工培养、菌种保存和杀虫试验。     

新疆、甘肃甜瓜病毒病的鉴定及防治

对甘肃、新疆两省(区)186个厚皮甜瓜病毒病标样的鉴定结果表明,病毒种类有黄瓜花叶病毒(CMV)、西瓜花叶病毒2号(WMV-2)和南瓜花叶病毒(SqMV)。其中WMV-2是主要病毒种类。不同地区或同一地区不同年份各个病毒的消长有较大的变化。桃蚜(Myzus persicae)、豆蚜(Aphis craccivora)及麦二叉蚜(Schizaphis graminum)可传播WMV-2,其中桃蚜的传毒效率最高。棉蚜(Aphis gossypii)可传CMV。种广可传带SqMV,其带毒率为7.6%。对1300个甜瓜品种及材料的抗病性试验结果没有发现任何免疫和抗病类型,但白兰瓜类型较哈密瓜类型抗病,薄皮甜瓜较厚皮甜瓜抗病,其中中国梨瓜龙田一号发病很轻。覆盖银灰膜、喷高脂膜及种植高粱隔离诱杀带等综合防治措施可使发病率减少82.0%,增产15.7—40.5%。     

IDENTIFICATION OF MANAGEMENT OPTIONS FOR A NITISOL OF SEMI-ARID AREA OF KENYA

<正> The objective of this study is to identify the management options for a Nitisol ofKibwezi area, Machakos District, Kenya. The management problems identified were: highexchangeable sodium percentage (ESP), 6-30; low organic carbon, 0.73-1.0; compactB-horizon; and low moisture retention capacity, 70 mm/ m. More than 40% of the total volume of the topsoil contained pores of effective diameter     

新疆哈密瓜病毒病毒源的分离和鉴定

新疆哈密瓜是驰名中外的特产,是我国重要的外销产品之一。五十年代末,六十年代初,由于病毒病的感染,使哈密瓜产量降低,含糖量下降,严重地影响了哈密瓜的产量和质量。 1980～1981年,在新疆石河子,吐鲁番和昌吉等地进行调查时,在哈密瓜和其它瓜类上采集病毒病标样19个,通过鉴别寄主,血清学和电子显微镜的鉴定,把19个标样分为两大类。一类寄主范围广,除侵染葫芦科外,还侵染豆科、茄科、藜科、菊科等多种植物,与黄瓜花叶病毒(CMV)血清发生明显沉淀反应,电镜下观察为球形粒体,确定为CMV的一个株系,另一类寄主范围狭窄,除侵染葫芦科外,还侵染豆科、藜科。电镜下形态为长线条状。与WM-V-2血清发生反应,应为西瓜花叶病毒2号(WMV-2)。WMV-2是哈密瓜病毒中发生最严重的毒源。占田间病株90％以上。