AN HPLC METHOD TO STUDY THE UPTAKE AND PARTITIONING OF THE ANTIOZONANT EDU IN BEAN-PLANTS

The chemical compound EDU -[2-(2-oxo-1-imidazolidinyl)-ethyl]-N'-pheny lurea) has long been used as an antiozonant to protect plants from ozo ne damage. However, as there is no assay available to determine its co ncentration in plant tissues its mode of application is still a matter of controversy. In the present study the uptake and distribution of E DU in bean plants (Phaseolus vulgaris L.) grown hydroponically in the greenhouse (August-September and January-February) with 3 mg EDU l-1 n utrient solution was investigated. EDU was analysed by a newly develop ed HPLC technique using reversed phase separation and UV-detection at 240 nm. Two methods were developed for the quantitative analysis of ED U in the nutrient solution and in different plant organs, respectively , and the identification of the EDU peak in the various samples was co nfirmed by the UV spectrum recorded with a photodiodearray detector. E DU could be detected in the range of 8-700 ng. There was no change of the EDU concentration in the nutrient solution without plants and with plant culture indicating the compound to be taken up with the nutrien t solution. EDU was also detected in the stem exudate of decapitated p lants. After two weeks of EDU treatment, only 4% of the EDU lost from the nutrient solution were found in the plant tissue. Of the EDU conte nt of a total plant (63 mug) 17% were found in roots, 4% in stems and 79% in leaves. The EDU concentration was highest in the intercellular washing fluid of the leaves and values for the apoplastic fluid were c alculated to be about 37 mg l-1 and 15 mg l-1 in plants grown in summe r and winter, respectively.