Enkele waarnemingen over versmelten van zoösporen bij Phytophthora infestans (Mont.) de Bary

Summary Zoospores ofPhytophthora infestans were seen to fuse in pairs. Generally within 30 min. after zoospore discharge, fusion started by the formation of a connection between touching zoospores. Gradually the connection became shorter and thicker (fig. 1,2 and 3), and within 30 min. the two zoospores united to form a spherical body (fig. 4). The flagella were thrown off just before the compound zoospore assumed the spherical shape. The compound zoospores germinated by a germ tube within 30 min. after their formation. The analogy withCritopoulos' observations on zoospore fusion inP. capsici is discussed.     

DDT与穆勒

DDT化学名称为2,2—双(对氯苯基)—1,1,1—三氯乙烷,一般指各种以此化合物为原药的杀虫制剂。20世纪DDT曾广泛应用于卫生害虫和农林害虫的防治,为预防疾病和防治农业害虫作出了巨大贡献,因此首次发现DDT杀虫活性的Paul Hermann M櫣ller(穆勒)获得了诺贝尔奖。但是很多中文文献中,在涉及穆勒的贡献以及获奖情况时,存在许多简单的错误。如《世界发明》(2002年第11期)中“DDT的兴衰史”一文认为是瑞典化学家穆勒因为发明农药DDT,于1944年获得了诺贝尔化学奖;而《图形科普》引自“21世纪科学与技术”一文中“昆虫学家提出建议重新启用DD…     

关于666、DDT的降解问题

七十年代开始,不少国家相继宣布禁止生产和使用666、DDT。但残留在土壤中的666、DDT仍为数不少。以天津汉沽区为例,该区7.2万亩耕地中6万亩种植粮食,平均含666为0.1732ppm;DDT为0.031ppm,7.2万亩土壤中(以耕作层计算)666残留达1871