Die Postulate von Koch und ie Luftverschumtzung

In 1891, the pathologistKoch postulated that injecting a pathogen into a plant (an animal, etc.) must result in damage identical to that caused by the same one under field conditions. This postulate has to be valid also for research on all aspects of air pollution and its “environment”: air pollutants applied to healthy plants during an experiment must cause the same damage as they do under field conditions. This postulate, however, has not been considered in research concerning air pollution and its effects on plants. Therefore, in part contradictory results may be found today in the voluminous literature on this problem. On the basis of visible symptoms of injury to plants it has been possible to establish grades of sensitivity of tree species to air pollution. Daily and annual mean values of air pollutants for certain areas were obtained; foliar analyses aimed at finding out about particular air-borne harmful substances helped—but regardless of all, there is no clear perception about the nature of air pollution. The authors presents a comprehensive literature review. At the same time they also point out that the “air pollution environment” is a many-layered system which is dependent on other facts, too, especially in regard to potential injuries to plants. The major harmful substances and their chemical compounds are discussed including the sphere of the plant cell, and biochemical questions. Research now not only has to consider parts of the problem (e. g. effects of mean levels of a certain damaging agent), but must rather focus on the problem in its entirety with all its ramifications. It is not sufficient to investigate just the physiological effects of air pollutants on tree growth; the effort to perceive the “air pollution environment”, too, has to be included as being equally important.