黄杜鹃提取物对亚洲玉米螟生物活性的研究

本文报道了闹羊花素 - ( Rhodojaponin- ,简称 R- )和黄杜鹃花乙酸乙酯 ( Et OAc)提取物对亚洲玉米螟 Ostrenia furnacalis Guenée3龄幼虫的拒食、生长抑制和毒杀作用。以饲料柱法测定 R- 和 Et OAc提取物的非选择性拒食作用 AFC50 为 77.0 2和 384 .30 mg/ kg,而以虫重法表示时 ,则分别为15.60和 2 55.4 4 mg/ kg。以 R- 2 0 0 mg/ kg连续饲喂 4天后 ,换为无毒饲料至 15天 ,试虫死亡率为86.67% ,L T50 为 2 .99天 ;以 Et OAc提取物 2 0 0 0 mg/ kg处理时 ,同期的死亡率 66.67% ,LT50 为 3.85天。R- 和 Et OAc提取物的生长抑制中浓度 IC50 分别为 9.30和 39.64mg/ kg。文中还讨论了亚洲玉米螟拒食作用的测定方法和 R- “取食后效应”等作用特点     

川楝素与青虫菌等农药混用对菜青虫增效作用的试验

川楝素分别与苏芸金杆菌(B.t. Var.galleriae)、青虫菌6号、雷公藤根粉乙醇抽提物以及化学农药乐斯本混用,对保护作物避免菜青虫(Pieris rapae L.)幼虫的取食为害有明显的增效作用,而且对幼虫的化蛹及蛹重都有明显的仰制作用,具有理论和实际意义.     

松突圆蚧的化学防治

经过应用10多种化学农药及其与植物油、矿物油的混合制剂进行室内药效筛选、林间地面喷雾试验和两年的飞机防冶试验,我们研制出能有效地防冶松突圆蚧(Hemiberlesia pitysoPhila Takagi)的药剂配方-植物油与矿物油的混合油剂。 这种混合油剂在小区试验巾用5甲。浓度,防治效果可达98.5%;用20%浓度进行飞机喷雾,药量折合5千克/亩,防治效果也达70%以上。这种混合油剂对松突圆蚧的重要天敌红点唇瓢虫(Chilocorus Kuwanae)成虫和丽蚜小蜂( Encasia sp.)安全,对环境一般无不良影响,同时乳化效果好,配制方便,值得开发应用。     

荔枝蝽象的化学不育试验

在广东省,荔枝蝽象(Tessaratoma papillosa Drury)雄虫生殖细胞对噻(口替)派(硫代三乙烯磷胺)的不育作用有二个敏感期,即生殖细胞受伤害的敏感期和对显性致死突变诱发的敏感期。这二个敏感期分别在7月中旬和翌年2月中旬,只有在生殖细胞对显性致死突变诱发的敏感期对荔枝蝽象雄虫进行不育处理才有实际意义。2月中旬被0.6%噻(口替)派水溶液浸渍的雄虫和正常雌虫配对后,卵的不孵化率达99.5%。2月中旬被哔噻兹[P,P-双(1-氮丙啶基)-N-甲基硫代磷酰胺]熏蒸2.6小时后再被0.2%噻(口替)派水溶液浸渍的雄虫和正常雌虫配对后,卵的不孵化率为99.3%。这二种处理方法对雄虫的交配竞争能力和死亡率基本没有影响。雄虫被0.6%噻(口替)派水溶液浸渍后24小时才出现较大的不育效应。进行不育雄虫大笼(2.2×2.2×3M³)释放试验,当不育雄虫、正常雄虫和正常雌虫的比例为80:10:10时,上述二种方法处理的不育雄虫分别导致94.4%和96.5%的卵不孵化率。初步观察到不育卵对跳小蜂(Ooencyrtus sp.)的产卵量和羽化率没有影响。上面试验结果表明,在华南地区应用不育剂防治荔枝蝽象看来是一种有希望的方法。扫描电子显微镜观察2月中旬0.4%噻(口替)派水溶液浸渍的雄虫的贮精囊中精子,发现精子密度降低、排列不整齐。浸渍雄虫的噻(口替)派水溶液浓度为1.8%时,透视电子显微镜观察处理雄虫睾丸精子横切面,可见部分精子的轴丝遭到损伤。     

Cardiac Responsiveness to Chronotropic Agents in the Cobra, Naja naja L.: Effect of Temperature and Thyroid Hormones

Cardiac responsiveness to isoproterenol, phenylephrine and parathyroidhormone have been studied in isolated cobra snake atria. Thepositive chronotropic responses to these agents are increasedunder elevated metabolic conditions: high temperature and tri-iodothyroninetreatment. The enhanced cardiac reactivity provides greatercardiac output in animals with increased metabolic demands.In view of the different receptors being stimulated by theseagents, theenhanced cardiac responsiveness is a general oneand, most likely, a result of increased metabolism.     

Life stage‐dependent effects of experimental heat waves on an insect herbivore

1. Worldwide concern about the consequences of climate change has prompted efforts to understand and predict the responses of populations to changes in temperature. 2. A heat wave can adversely affect organisms, may affect different life stages differently, and could decrease populations. In this study, green peach aphid [Myzus persicae (Sulzer)] nymphs, reproductive adults, and late‐reproductive adults were exposed to a heat wave, defined as 5 °C above the control temperature regime for five consecutive days. 3. The negative effects of experimental warming on development, reproduction, and survival negatively affected population growth. Nymphs and reproductive adults were more severely impacted than late‐reproductive adults. 4. Experiments designed to mimic temperature regimes can assess the direct effects of climate change on individuals and populations. Our study highlights the importance of assessing the life stage‐specific responses to heat stress.     

A Method for Material Parameter Determination for the Human Mandible Based on Simulation and Experiment

In cranio-maxillofacial surgery planning and implant design, it is important to know the elastic response of the mandible to load forces as they occur, e.g., in biting. The goal of the present study is to provide a method for a quantitative determination of material parameters for the human jaw bone, whose values can, e.g., be used to devise a prototype plastic model for the mandible. Non-destructive load experiments are performed on a cadaveric mandible using a specially designed test bed. The identical physiological situation is simulated in a computer program. The underlying mathematical model is based on a two component, linear elastic material law. The numerical realization of the model, difficult due to the complex geometry and morphology of the mandible, is via the finite element (FE) method. Combining the validated simulation with the results of the tests, an inverse problem for the determination of Young's modulus and the Poisson ratio of both cortical and cancellous bone can then be solved.     

隔指孢属一新种

在对北京郊区果园捕食线虫真菌的季节性分布的研究中,常观察到一种隔指孢属中的真菌,经对其形态研究确定为一新种一北京隔指孢(Dactylella beijingensis Liu, Shen et Chiu),其主要特征为分生孢子梗分枝,每个分枝顶产生单一的分生孢子,分生孢子梗向顶渐细,长79-108-137 μm,基部宽2.5-3.0 μm,顶宽1.5-2.0 μm,产孢细胞菌丝型发育,分生孢子无色,纺锤形,4-6个分隔,在分隔处稍缆缩,大小为33.5-38.0-42.0 × 7.0-8.0-8.5 μm,未见厚垣孢子产生,未见捕食线虫器官。