EASY DETERMINATION OF PLOIDY LEVEL IN ARABIDOPSIS-THALIANA PLANTS BY MEANS OF POLLEN SIZE MEASUREMENT

Cytogenetic examination of transgenic Arabidopsis thaliana (L.) Heynh. plants obtained by Agrobacterium-mediated gene transfer to cotyledon- and root-explants or by direct gene transfer into protoplasts reveale d a high percentage of tetraploid or aneuploid transformants. Dependin g on the transformation procedure used, 13% (root explant transformati on), 33% (cotyledon explant transformation), or 38% (direct gene trans fer) of the transformants showed aberrant ploidy levels. A good correl ation between the ploidy level of a plant and the size of its pollen g rains was observed. This allows quick and simple testing of the ploidy level of transgenic Arabidopsis plants.