Abstract:

Objective: Polyploid varieties have very good performance in phenotype, nutrient content and stress resistance. The method of polyploid breeding was used, hoping to overcome the difficulties encountered in current breeding of Phyllostachys edulis, and to create new germplasm resources of polyploid varieties. Method: The imbibed seeds of P. edulis after soaking were treated with colchicine of different concentrations at different durations for mutation induction. Seed hypocotyl expansion was used as the indicator for early detection of mutation, and then DNA content of these candidates was identified by flow cytometry. The morphological, physiological and biochemical comparisons between diploid and homologous polyploid were performed. Result: 0.5 g·L^-1 colchicine could induce chromosome doubling of bamboo seeds after swelling, and 5% induction rate could be obtained by soaking with 0.5 g·L^-1 colchicine for 72 h and 1 g·L^-1 colchicine for 24 h. The flow cytometry detected that the relative DNA content of tetraploid P. edulis leaves was 2 times of diploid. Compared with diploid, the stomata density of the epidermis of the tetraploid was significantly decreased, the size of the stomata was significantly increased(P < 0.05), and the plant height, leaf length and leaf width of the tetraploid bamboo increased significantly, and the photosynthesis of the tetraploid plants was higher. Conclusion: The treatment of swelled seeds with colchicine can successfully induce tetraploid for P. edulis, and there are significant differences in physiological and biochemical characteristics between the tetraploid and the diploid.

Key words: Phyllostachys edulis, polyploid induction, colchicine treatment, flow cytometry, phenotypic characteristics