Abstract:

The effects of colchicine concentration and treatment time duration on the apical meristems of the seedlings in three species of Lagerstroemia indica have been conducted in this study, and the ploidy level was identified by morphological trait, chromosome number and flow cytometry techniques. The results showed that treated L.indica or L.indica var.alba with 0.5%-0.8% colchicine for 48-96 h lead to a high mutation rate, and the highest mutation rate (up to 54.17%) was achieved in the L.indica by treatment of 0.5% colchicine for 72 h. All the three tested species of L.indica have obtained a number of tetraploidy plants. The choromosome number of mutated plants was 2n=4x=96, while that of the control plants was 2n=2x=48. The tetraploid plants exibited some morphological and cytological variations, including larger and thicker leaves, darker leaf color, larger stomata, fewer stomata per unit area, more chloroplasts in stomata guard cell and longer pollen diameter. The ornamental value of single flower had also been greatly improved by increasing of flower diameter, petals and basal claw length.

Key words: Lagerstroemia indica, colchicine, polyploid, induction, identification