RESEARCH: Shrub Propagation Techniques for Biological Control of Invading Tree Species

Cornus stolonifera, Salix petiolaris, and Spiraea alba clones already located within the corridor of an electrical power line. To establish the efficiency of treatments, we examined the statistical differences of growth traits between species and treatments. An analysis of the effects of layering shows, after the first growth season, differences for all growth traits in only one species, Spiraea alba. After the second growth season, we observed the development of new aerial stems. Layering favors horizontal expansion of shrubs over height development. The third year after treatment, the effect of layering is reduced except for Cornus stolonifera, which continuously increases, as shown by the significant progression of the clone issued from the layer even five years after treatments. With the cutting back technique, we expected a distinct vertical growth of the shrubs at the expense of increasing the crown diameter. This technique would be best associated with the rejuvenation of clones, followed by a layering of new shoots to allow a horizontal expansion of the shrubs. Therefore, the formation of a dense shrub community by layering should be considered a valuable approach for the biological control of undesirable trees in powerline rights-of-way.     

萃取分光光度法测定工业废气中的游离溴

用萃取分光光度法测定工业废气中的游离溴，并对样品的采集与保存，萃取条件的选择进行了研究。结果表明，当溴的含量在１８．０－４５０．０μｇ／ｍＬ范围同时，吸光度与浓度具有良好的线性关系，方法的采样效率大于９９％，精密度和准确度较好当采集气体为１００Ｌ时，最低检出肖度为０．１４ｍｇ／ｍ＾３。     

Citrulline in amniotic fluid and the prenatal diagnosis of citrullinemia

We report relatively high citrulline concentration in amniotic fluid of a citrullinemic fetus suggesting that prenatal detection of this condition could be done on this basis in conjunction with a direct or an indirect determination of argininosuccinate synthetase activity in amniotic fluid cells.     

特种劳动防护用品实施安全标志管理的重大意义

特种劳动防护用品目前存在的“三乱”现象必须根治，国家采用“安全标志”管理特种劳动防护用品，必将促进保护劳动者职业安全与健康的防护用品质量的提高，对构建和谐社会产生深远意义。