Abstract

The immature embryos of Clivia miniata Regel. cv. Ranchang were in vitro induced with 0.00, 0.01, 0.03 and 0.05% colchicine treatment for 10, 20 and 30 d, respectively on Murashige and Skoog (MS) medium supplemented with 2.0 mg L^-1 a-Naphthaleneacetic acid (NAA) and 1.5 mg L^-1 6-Benzylaminopurine (BA). A total of 14 tetraploids were obtained with an average induction rate of 16.1%. The most effective treatment was 0.03% colchicine for 20 days with an induction rate of 30.0%. The stomata size (37.24 × 12.31 μm) of tetraploids was significantly larger than that of diploids (22.51 × 7.43 μm). The stomata density of tetraploids (13.80 mm²) was significantly lower than that of diploids (30.78 mm²). The chloroplast number of guard cells of tetraploids (41.53) was significantly more than that of diploids (28.00). Compared with diploids, tetraploids had thicker, wider, shorter, rougher and deeper-colorful leaves, fewer roots and slower growth. The leaf and stoma characteristics could be regarded as helpful indexes to identify colchicine-induced tetraploids in C. miniata.

Key words: Clivia miniata Regel., chromosome doubling, colchicine, tetraploid, stoma, chloroplast number.