EARLY DIAGNOSIS OF STRANGULATION OBSTRUCTION OF THE SMALL INTESTINE

Early recognition of strangulation obstruction of the small intestine is important in order that surgical relief may be undertaken before the bowel has been irreversibly damaged or the condition of the patient has so deteriorated as to make immediate operation unreasonably hazardous.In the presence of other symptoms, an operative scar, particularly on the lower abdomen, should alert the examining physician to the possibility of strangulation obstruction. (In a series of 100 cases, the greatest single cause of strangulation was adhesive bands subsequent to abdominal operation.)Other hallmarks of aid in diagnosis and in distinguishing early from advanced strangulation are discussed.X-ray evidence varies in accord with the rapidity of development and the stage of strangulation.Abdominal puncture may be utilized as a means of diagnosis with little risk.     

ABSORPTION OF HERBICIDES BY ROOTS

Crafts , A. S., and S. Yamaguchi . (U. California, Davis.) Absorption of herbicides by roots. Amer. Jour. Bot. 47(4): 248—255. Illus. 1960.—Many herbicides are used through soil. When 2,4-D*² was applied to culture-solution barley, bean, cotton, and Zebrina plants, there was evidence that the herbicide is held at high concentration by the roots. Very little of the labeled compound moved into the tops of barley, Zebrina and bean; a fair quantity was found in cotton foliage. Barley seedlings allowed to absorb 2,4-D*, ATA*, MH*, urea*, monuron*, dalapon*, simazin*, P³² and IAA* showed interesting differences. All chemicals were highly sorbed by roots, 2,4-D* was moved to tops in least amount, urea was next; the other seven were moved in larger quantities. ATA*, MH*, IAA*, P³², and dalapon* seemed readily phloem mobile; monuron* and simazin* seemed limited to xylem movement. Results are discussed in relation to the mechanism of root uptake.     

高水位条件下池杉根系的生态适应机制和膝根的呼吸特性

  池杉(Taxodium ascendens)属于典型的耐水树种, 掌握其根系对淹水环境的生态适应机制对于研究林木耐水机理十分重要。通过对江苏省里下河低湿地17年生池杉在高水位(6～10月淹水, 全年平均地下水位-5 cm)、中水位(8～9月淹水, 全年平均地下水位-18 cm)和低水位(常年不淹水, 全年平均地下水位-41 cm)条件下的根系进行调查, 结果表明, 池杉在高水位条件下形成细长的气生根, 气生根依附于树干北侧或潜伏于树干外表皮内侧和纵裂的树皮缝隙中; 中水位池杉能形成直径(7.9±2.2) cm、高(7.7±2.7) cm的膝根, 每株立木拥有膝根数(5.8±1.7)个; 低水位池杉也能形成膝根, 但个体小、数量少。林木地下和地上生物量均呈现出明显的高水位<中水位<低水位的趋势, 但是地下/地上生物量的比值却呈相反趋势, 表明池杉耐水性虽然很强, 长期处于较高水位时生长会明显受抑, 尤其是地上生物量生长受抑更显著。高、中和低水位池杉的地径/胸径之比分别是2.66±0.11、2.08±0.10和1.75±0.08, 说明水位较高的环境能促进树干基部的相对粗生长。长期淹水导致地下根的容重降低, 但是气生根和膝根的容重却明显大于地下根。高、中水位池杉细根的Fe和Mn浓度显著高于低水位, 其中Fe的浓度相差10倍以上, 但是叶的Fe、Mn浓度在不同水位之间没有显著差异。膝根的呼吸具有明显的季节差异, 8月和9月平均每个膝根的呼吸速率为2.1～2.5 mgCO₂&#8226;h^–1, 6月和11月为0.7～0.9 mgCO₂&#8226;h^–1, 3月为0.4 mgCO₂&#8226;h^–1; 膝根吸收O₂的摩尔数是释放CO₂摩尔数的4.6倍, 说明膝根吸收的O₂除了供自身呼吸, 大部分是提供给地下根利用。池杉之所以具有较强的耐水性, 与其在缺氧环境中能形成气生根和膝根、树干基部膨大和根系容重降低等有利于改善根系通气条件的生态适应机制密切相关。     

棉蚜在棉田中的发生和扩散

棉田中的棉蚜是由棉蚜的越冬寄主植物上迁移而来,这已由试验证明。但当棉蚜到达棉田以后,如何由少成多地扩散开来,造成棉田的灾害,是我们防治棉蚜工作中极需了解的问题。大家知道当早期治了极少数的棉蚜便可以防止了它的大批发生,更重要的是免得棉株受害影响产量。由於棉蚜的繁殖力强大,在短期内便可由少成多由点及面,往往使人不易察觉它的发展过程和规律。同时便可以搅乱了我们的防治措施,而造成我们工作中的很大损失。