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 te sters of mutagenicity, the young inflorescence-bearing nodal and/or ax illary cuttings of clones BNL 02, KU 27, KU 7 and KU 20 were cultivate d with nutrient solutions, and the flower production, stamen-hair grow th, and spontaneous and induced somatic pink mutation frequencies in t he stamen hairs observed in the cuttings of each clone were compared w ith 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 sponta neous and X-ray-induced somatic mutation frequencies were comparable t o those in potted plants. Using the BNL 02 cuttings, however, the muta genic effect of nitrofurazone was detected for the first time in highe r plants. On the other hand, the shoots with roots of clone BNL 4430 d ivided from the potted plants and cultivated with a nutrient solution exhibited excellent results in all aspects; i.e., the flower productio n, flower size, stamen-hair growth, and X-ray- and MMS-induced mutatio n frequencies being almost identical with those in the potted plants, and the spontaneous (background) mutation frequency being lower than t hat in the potted plants. The shoots with roots of clone BNL 4430 were thus judged to be the best Tradescantia tester of mutagenicity, requi ring much smaller space than using the potted plants and supplying muc h larger samples much more constantly than the cuttings of other clone s.