Flower production, stamen-hair growth, and spontaneous and induced somatic mutation frequencies in Tradescantia cuttings and shoots with roots cultivated with nutrient solutions

For establishing more efficient blue /pink heterozygous Tradescantia testers of mutagenicity, the young inflorescence-bearing nodal and/or axillary cuttings of clones BNL 02, KU 27, KU 7 and KU 20 were cultivated with nutrient solutions, and the flower production, stamen-hair growth, and spontaneous and induced somatic pink mutation frequencies in the stamen hairs observed in the cuttings of each clone were compared with those in the potted plants of the same clone. The cuttings tended to show poorer flower productions, smaller flower sizes and decreases in the number of hairs, as compared with potted plants, but the spontaneous and X-ray-induced somatic mutation frequencies were comparable to those in potted plants. Using the BNL 02 cuttings, however, the mutagenic effect of nitrofurazone was detected for the first time in higher plants. On the other hand, the shoots with roots of clone BNL 4430 divided from the potted plants and cultivated with a nutrient solution exhibited excellent results in all aspects; i.e., the flower production, flower size, stamen-hair growth, and X-ray-and MMS-induced mutation frequencies being almost identical with those in the potted plants, and the spontaneous (background) mutation frequency being lower than that in the potted plants. The shoots with roots of clone BNL 4430 were thus judged to be the best Tradescantia tester of mutagenicity, requiring much smaller space than using the potted plants and supplying much larger samples much more constantly than the cuttings of other clones.