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2003
Poster
Titel
Development and validation of a method to determine threshold values for effects of genetically modified plants on the habitat function of soils
Titel Supplements
Poster at the 13th SETAC Europe Annual Meeting, Hamburg, 27.4.-1.5.2003
Abstract
The safe cultivation of genetically modified plants (GMP) requires a comprehensive investigation of possible harmful soil changes - especially with respect to the natural habitat function of soils for soil organisms, as mentioned in ยง2 of the BBodSchG (Bundesbodenschutzgesetz; German Federal Soil Protection Act). This study outlines a concept for a multi-stage test that can be used to investigate the effect of transgenic active molecules on the habitat function of the soil. Moreover, the general feasibility of the approach is examined. Test strategy: Genetically modified plants can principally influence the soil via two major pathways. On the one hand gene products (e.g. proteins) encoded by foreign DNA may be secreted as root exudates by the living plant, while on the other hand either these gene products or the foreign DNA itself can reach the soil through the decomposition of plant material. The concept elaborated in the study is a stepwise approach to examine the effect of 1) the pure gene product, 2) the root exudates, and 3) the necromass of genetically modified plants on the habitat function of the soil, using Bt corn as an example. To determine any potential effects, standardized ecotoxicological methods will be used in combination with modern molecular biology techniques. So far, no limitations in the feasibility of the methods used have been detected. It was shown that the reproduction tests could be modified to take into account the use of dried plant material as a food source (increased exposure of the soil organisms). The material was accepted as food by the test animals and was sufficiently nutritive to yield reproducible results regarding survival and reproduction rates. At present, the selected test strategy seems to be suitable to assess the effects of transgenic active molecules on the habitat function of the soil.
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